Spray Application Methods for Furniture Finishing - …infohouse.p2ric.org/ref/25/24064.pdf · Spray Application Methods for Furniture Finishing November lo, ... Automatic Spray Equipment

Spray Application Methods for Furniture Finishing

November lo, 1994 Greensboro-High Point Marrion

Greensboro, North Carolina

Sponsored by the Society of Manufacturing Engineers in cooperation with the Association for Finishing

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SPRAY APPLICATIONS

FOR

FURNITURE FINISHING I B Y

JERRY P. H U N D

SPRAY APPLICATIONS FOR FURNITURE FINISHING

TABLE OF CONTENTS

SUBJECT

Introduction .................................................... Spray Application Processes ....................................

Viscosity .......................................................

A i r Nozzle Selection ............................................ High Volume Low Pressure - HVLP ............................. Fine Tuning Your HVLP System ................................ Hose and Fittings .............................................. Compressed Air Supply ........................................ Material Supply ................................................ Plural Component Spray Systems ............................... Airless Spraying ............................................... A i r Assisted Airless ............................................ High Transfer Efficiency Spray Application Systems ............

Automatic Spray Equipment ..................................... Safety Considerations in Paint Application ...................... Paint Curing By Infrared Catalytic Thermoreactors ............. Spray Booths .................................................. Operator Techniques ............................................ How To Maintain A Spray Gun .................................. Guide To Finishing Technology ................................. Notes .............................................. ; ............

Dirt Is A Four Letter Word to Furniture Finishers ..............

Compressed A i r Spray Gun Principles ...........................

Hot Spraying ...................................................

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SPRAY APPLICATIONS FOR FURNITURE FINISHING Jerry P. Hund

INTRODUCTION

Since the days of the cave man, man has applied materials of one type or another to protect and/or decorate his possessions. Furniture has always been one of man's most prized possessions. Although many materials have been used, wood has remained the most popular material for furniture. Many people down through history have worked with wood in one form or another - the most famous of which being the one referred to as "The Carpenter's Son". One thing that has always posed itself as the most difficult challenge is how do we finish our furniture in order to give it that protection and decoration that will make it out-sell the . competion. @, Q! kLl&G - J=Y

a4-Q -p-+-F Man has developed many coatings and methods of applying these coatings to furniture down through history, many of which remain in use today, and rightly so. With the dawn of the Industrial Revolution, newer coatings and processes emerged. Compressed air atomization became popular in the early part of the twentieth century. This process allowed furniture finishers to speed up production in order to keep up with demand. In the middle part of this century, newer finishing processes emerged to compete with compressed air. Airless and electrostatic spraying proved worthwhile to many furniture manufacturers and other manufacturers as well.

What's new in spray equipment for furniture finishing? Really, the last major breakthrough was the invention of the spray gun to replace the brush. In .the decades since that time changes have been in the form of continuous improvements and refinements in the equipment to obtain better atomization of the coatings, better finishes, improved production and lower cost.

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As new and improved coating materials have entered the market, spray application equipment has been adapted to spray them. As production became mechanized, finishing equipment met the challenge with automatic equipment. When regulations called for reduced emission of volatile organic compounds (VOC), manufacturers of spray equipment found new ways to improve the transfer efficiency of spray equipment and to clean exhaust air.

Today, this evolution in spray equipment continues unabated as new coating materials and manufacturing methods come into use.

Although the basic principle of operation remains unchanged, spray equipment has become highly refined and diversified. New manual and automatic spray gun designs and nozzle combinations meet the requirements for optimum coverage of an almost endless range of paints, lacquers, stains, two- component materials , adhesives, and other materials.

The application of coatings by computer operated vertical and horizontal reciprocators, spindle and rotary machines, and similar automatic devices remains a major method of increasing production and controlling the quality of the finish. These systems can be varied to meet many requirements. Overspray and paint consumption are minimized by electronic sensors to control the triggering of the guns in conformance with the shape, size and movement of the product being finished.

Electrically driven robots are probably the latest addition to the wide array of finishing equipment on the market today. Their adaption to spray finishing operations solves many problems beyond the capability of standard automatic equipment. Because a robot can reach into and around a product, it is ideal for painting irregular shapes and the interior of enclosed areas. Prior to the use of robots, these operations required manual finishing, frequently with considerable operator discomfort or hazard.

Robots offer economies where the conveyor in the finishing department carries a variety of products, each requiring its own spray pattern. Thanks to today's advanced electronic equipment, a robot can sense the product in front of it and select the right program from its memory to finish the product uniformly. A robot is also an ideal substitute where the health and safety of workers is in question. However, most furniture lines still require the skill of trained sprayers to "read the surface" of the wood before manually spraying the furniture.

Recent development in finishing equipment include a process which combines two finishing processes into one. Air Assisted Airless, when used under ideal conditions, employs the best features of compressed air and airless spraying. This method uses a specially designed gun and pump. The fluid is delivered to the spray gun at low airless pressures (150-800 psi) where it is partially atomized by an airless tip. Atomization is completed by introducing low amounts of atomizing air (5-30 psi) into the airless pattern. The result is a finely atomized pattern that closely resembles that of compressed air. This process also reduces fog and overspray, allows spraying into cavities, provides a higher film build per pass, while consuming up to 50% less air that an ordinary compressed air finishing system. All this adds up to improved transfer efficiency and costs savings.

We can also include the process of electrostatic air assisted airless for even greater transfer efficiencies. Although most wood furniture finishers would select air assisted airless, many metal finishers may want to consider the electrostatic options available to them.

Recently, the need for furniture finishers in many areas of the country to comply with stricter emissions regulations has forced them to change to more efficient spray systems. Several new processes have recently emerged that offer great Potential for furniture finishers.

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The first process is commonly referred to as high volume low pressure (HVLP) atomization. HVLP atomization works similarly to conventional air spraying with several notable exceptions. First, jets of high pressure low volume air exiting the nozzle are now replaced by soft columns of high volume low pressure air. Secondly, larger interior diameter air hoses feed specially constructed spray guns which may restrict the atomizing air pressure within the spray gun, or have its pressure restricted prior to its entry. Finally, air used to atomize the coating can originate from high speed turbine operated blowers or from existing air compressors. Regardless of the manufacturer, all HVLP systems use between 15-30 cfm (volume) and 1-10 psi (air pressure) to atomize a soft highly efficient air spray. Although exceptions exist, many turbine operated HVLP systems have found a home in smaller wood finishing operations due in part to their portability. Air conversion HVLP systems have made a dominant showing in larger furniture plants mainly because of their ability to use existing shop air.

Newly released HVLP air assisted airless spray guns allow high speed furniture lines to keep up with production while still achieving the benefits of HVLP.

The second process is known as low pressure low volume (LPLV) air atomization. It can also be considered a low pressure air assisted airless system. LPLV atomizes material with jets of low pressure low volume compressed air strategically impinged into a flattened cross sectional fluid stream exiting the spray gun.

Fluid pressures range from 20-70 psi, air pressures from 5-15 psi and air volume consumption between 3-8 cfm. When compared to air assisted airless and compressed air atomization the figures illustrated here demonstrate that it truly is a low pressure low volume atomization process. As with turbine

operated HVLP sprayers, LPLV systems are also very portable. LPLV is ideal for spraying low viscosity coatings such as Stains, sealers and some top coats on a low production finishing line or custom finishing operation.

Both methods described here offer unique advantages such as high transfer efficiency (65 -75%) , sprays well into recesses without excessive bounce back, reduced material costs, lower emissions, reduced booth maintenance and hazardous waste and are easy to operate. As improvements are made in both systems, look for improved atomization quality.

In some cases, these newer systems may not match the ultimate finish quality of compressed air atomization. However, most furniture finishers are finding both systems to adequately meet their needs and the EPA's.

R A new process, developed by Union Carbide, called the Unicarb process substitutes carbon dioxide for a substantial quantity of the fast evaporating solvent (up to two thirds) normally used in the spray application of certain coatings.

The UnicarbR process uses carbon dioxide that has reached a super critical state. When C02 is heated to a critical temperature of @ 00'F and a super critical pressure of @ 1070 psi the gas turns into a dense fluid which is used as a substitute for a large portion of the solvent. Delivery equipment is used to accurately meter and mix the C02 with. the coating concentrate. Finally the mixture is sprayed under airless conditions either manually or automatically.

The furniture industry is targeted as a major end user for this process for obvious reasons. As improvements are made and costs reduced, the UnicarbR process will become a major player in this industry as well as other industries.

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Electrostatic application of coatings has ushered in new economies in the finishing of furniture. This method has long been an advantage in finishing metal desks, filing cabinets, and other metal furniture, but recent developments make it practical for use with wood furniture when the surface is properly prepared. The high transfer efficiency of electrostatic spray finishing not only saves material but is a major help in reducing VOC levels (due to the reduction of the coatings used) in the exhaust from spray booths.

As with other spray equipment, electrostatic applicators are constantly undergoing improvements. Smaller, safer, more maneuverable hand guns are now in use. Some even use air operated turbines mounted directly on the spray gun which provide the necessary voltage. This eliminates the power supply and cable to the gun.

Electrostatic HVLP is now available for those operations that require high transfer efficiency along with electrostatic "wrap".

The development of compact high speed, electrostatic rotary bells and discs are adding a new dimension to this method of applying coatings. Some of the first electrostatic rotary' disc installations involved the coating of spindles, gun stocks and other long cylindrically shaped wood components.

Transfer efficiencies as high as 95% are possible with these units. This equipment also makes it possible to effectively atomize the new high solids and water borne coatings which are becoming popular in furniture finishing.

The rapid growth in the use of two-component materials such as polyesters (i.e. Wet Look), epoxies, polyurethanes, etc. has given rise to new equipment for precise metering, mixing and dispensing of the two components. Such equipment ranges from fairly simple but accurate metering pumps delivering a given

ratio, to highly sophisticated computerized permit selection of a wide range of component

systems that ratios which

accurately monitor and report each step of the finishing operation.

A new generation of color changers now make it easier, faster and more economical to shift from one color or material to another in operations where products are finished in a range of colors or coatings. The change is quick, and eliminates the time-consuming job of purging one material before another can be sprayed.

Circulating systems, serving'from two to many spray stations, deliver coatings to all spray guns in the plant at the same uniform viscosity and color, assuring that parts finished in different work areas match in the final assembly.

Such a system offers greater safety by eliminating the handling and clutter of individual material containers located at the spray stations. The development of improved paint pumps make circulating systems more efficient.

Pumps, used to supply coating to spray equipment and to move it through circulation systems, have also been subject to evolution. New designs and materials contribute to extended service life and greater efficiency. Abrasive and corrosive fluids can be pumped for longer periods without pump maintenance. Air motors used on such pumps are now much quieter, operating at noise levels under those required by OSHA. Hydraulic power supplies have replaced air motors at many locations with little or no maintenance. Diaphragm pumps cah handle most coatings with less down time and is simple to repair.

There will continue to be many and constant changes and mergers in existing equipment and methods as new materials and technologies come from the research and development

laboratories of the world. developments in electronics adapted to product finishing quality, and lower cost.

Many of the revolutionary and computerization will be to improve automation, finish

Spray booths have undergone some major changes of late. For many companies the spray booth may still be the dirtiest place in the shop. For some spray operators, the feeling is the sooner they could transfer out of this area the better. Often it is unclean, noisy, poorly ventilated and illuminated. Coupled with this is the problem of what to do with the hazardous waste at clean up time. Those purchasing water wash spray booths soon realized they also purchased a problem with waste disposal. Those converting to or purchasing dry filter spray booths were not exempt from these problems either. OSHA

inspectors continue to find more violations in the spray booth and adjoining areas than anywhere else on their inspections. Finally, dirty finishes are usually attributable to poor housekeeping in the spray booth.

Spray booth suppliers understand these concerns and are busy developing alternatives. systems can now turn 12 drums of hazardous liquid waste into 1 or 2 drums of dry waste which in some cases can be considered landfill. Quiter fans help keep noise levels within OSHA levels. Easy to spray water based strippable white and clear booth coatings help keep walls and windows clean. Improved holding capacity of dry filter media can now reduce filter Cost. Long lasting galvanized or stainless steel booth panels have replaced the rust prone black iron panels of several years ago. Carbon adsorbtion and incenerators may become more popular as costs are reduced.

Newly improved centrifuge cleaning

When spray booth manufacturers find a way to easily remove solvent emissions from coating materials before being discharged into the atmosphere, EPA guidelines could become almost extinct.

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As we approach the 21st Century, the furniture industry will see a major emphasis placed on cutting emissions, (through the reduction or elimination of solvent based coatings) improving quality while cutting costs, and improving the transfer efficiency of its finishing operations. Improving transfer efficiency will not only cut material and disposal costs, but also allow furniture plants in many states to remain open for business. Recently enacted EPA regulations in some states now require methods of application to provide a 65% transfer efficiency. Thus many furniture plants will want to re- examine their finishing operations to see if they can switch to more efficient and less polluting methods of atomization.

Regardless of the hype associated with today's spray application systems, all have their advantages and limitations. What may be suitable in one plant or operation may not be suitable in another.

Equally important is the idea that regardless of the process selected, and the equipment supplier, all require maintenance. There is not maintenance free spray equipment in existence for sale today.

The purpose of this manual is to introduce you to the most current and popular forms of spray finishing and its related equipment used in the furniture field today, to show each one's advantages and limitations, and to reinforce . the 1ettureJdiscussions of the workshop. Although limited

I discussion on coating materials is made, this manual will deal I I primarily with the proper selection, operation, and I

maintenance of the spray finishing equipment.

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Although many illustrations and references are of non- furniture related trades, my purpose is to show you that regardless of the product, or ware, our objective is to put that material onto the product in the most successful and cost efficient

The spray equipment and materials you're using today may also be found in other trades.

Armed with this knowledge and a little common sense, you should be able to examine your own furniture finishing operations and see what improvements can be made to save you money, improve quality and allow you to meet EPA emissions requirements. I hope you will try out some of the ideas suggested in this manual.

Many thanks go out to those assisting me and contributing to the contents of this manual.

Spray Application Processes

Rd. No. hOGe8B -8WS Umltrtloni

1. Air Atomizatii-Most m m o o l y Ccmplete pattem control. Uses m m air. Creates most fog. used for industrial finishing. Finest atmizalim. Low transfer effiiancy.

1.1 Siphon Fed-Uses vacuum created Lcwest cost. Operata canies w g h t of material at mzzle to draw material from Less maintenam. a gun. cup. External atomizati. Change colon q u w . Sprays lght materials only.

One qi. max. Spray position limited,

Creales moa log. I 12 Pressure Fed (extemal atomi- Delivers m m material than 1.1. Cwumes most air. zalloo)-Uses external pressure source. tank or pump, to force material f r m nozzle. Material and air mix outside of nozzle.

tion)-Material and air mix inside

Wider viscoriiy range. Sprays mosi materials. No air nozzle Mer. Spray in any posiiim. Mependent control over air and fluid pressures.

Larger pattems. 1.3 Pressure Fed (internal atomiza- Less fog than 12. Coarse a tm iza t i . Fixed pattems.

Nozzles war. Fast drying coatings

Not all materials can be heated. with heated material-Same as 1.2 Special paint fmulatms are except material is heated to reduce required. A d d t i equipment to viscosity. a better finish. Better adhesion. maintain. Equipment must be

explosion proof (el%arical). Hgh electrical demand. Reduces pot lib for catalyzed coatings.

Atomizatin not as fine as that of air spray. Not recommended fa heavy materials Q where hqh pfoduciicm is Rquired.

noule. Less air msumpiion. not reCo"ende4.

1.4 Pressure Fed (external atomization) Better control. Fledumd air and fluid pressures. Limits overspray and rebound. Finer stomizatm for

More film build per coat. Reduced Mushing. Reduced soknt use.

Hgh lrdnsfer efficiency (65% to 75%). Sprays well into recesses and cavities. Very portable -em.

1.5 Low Fmssure Low Volume Atomization-Material is atomized by LPLV jets of air optimumly positioned to impinge onto Me fluid stream of elleptical cross section (inslead of the cowentiara1 round me) exiting the spray gun.

Atomizatm-Similar to that described in 1.2 except higher d u m e and l m r pressure (HVLP).

Atomization caused by release of hgh fluid pressure through small oriflce. Most widely used by painting UXltraCtors & maintenance painters. Equipment requires top

1.6 Hgh Volume Low Ressure Same advantages as described in Same disadvantages as described 1.5 plus cDmpties with most air quality regulations.

in 1.5 plus m e systems fa generating HVLP air may be expensive.

injection. Hgher rate of werspray Sharp patterns: dHKuit to blend. Expensive nozzles (tips). Coarse atomizatm may flood surface.

maintenance.

Same limitations as 2.

2. Airless (hydraulic) Alomizatim- Hgh fluid capability. Large Potentially hazardous hydraulic patterns. Fastest spray applicatm process. Low air m s u m p i h . Limited fog and "bounce back -permits spraying into cavities.

2.1 Airless A l m i z a t i (heated)- Better Row of material. Strki maintenance. same as 2 except with heat to reduce viscosity. Used by furniture manufacturers and industrial finishers.

pressures than airless (normally below 1OM) PSI). Low pressure air IS added via the air nozzle to furlher atomize the already pre-atomized spray Used by furniture and industrial finishers.

Hgher solids per pass of gun. Viscosity control. Finer atomization than 2.

2.2 Air-Assisted Airless-lower fluid Material savings 50% better than Atomization not as fine as air spray plus lower overspray and fog. Less tip wear: longer pump life ihan airless. Hgher film build per pass than air spray.

Air Spray. Hydraulic injecton may occur. Tip plugging. Stra maintenance.

Rd. NO. h..r Adnnla9.r Umitatlonr

2.3 Air Assisted Airless (Heated). Better flow of material. Stnct matntenarce. Same iimitatlons as 2.2. Uses same principle as 2.2 with the

a d d i l i of heat to reduw viscosity and improve flow.

differem between paint dispenser flow s~eed rotatino disc or bell) and

Higher solids per pass of gun. Viscosity mlrol. Finer atanizatm than 2.2.

3. Electrostatic Atmiraton-VoHage Hgh transfer efficiency @ 65-95%. Parts must be conductlw. "Wrap" around effect. waling other surfaces.

Limit to shapes that may be coated. Hiah oroductlcn rate reouired.

*ran causes paint-to be attract& to the grounded work. Used by most

Minimum overspray. . ~.

HGh &Itage andspinning cup or disc may be hazardous.

appiiance manufacturers. Hgh production of uniformly shaped pa*.

3.1 Electrostatic Attractim-Material "Wrap" around effect. Scme COnductive materials will is atomized using t W B n t i i a l require special equipment, air. airless. or air-assisted airless overspray. Parts must be cwductiw. principles. Particles are electrically Difficult to penetrate cavities or charged and attracted to the work. recesses with power supply on. Electeity may be turned olf to permit normal spraying.

Heated Materials)-Same as 3.1 except materials are heated.

Material savings through minimized

Use with or without e lec td l Charge.

3.2 Electrostatic Attraction (Using Ahiliy to usa systems coupled Same l imitat is as in 1.4. 2.1 together to get all the advantages as in 1.4.2.1.2.3 and 3.1.

and 3.1.

3.3 Hgh Speed Rotataral Atanizers- High transfer efficiency. Par& must be conductive. HQh speed (10K-70K RPM) rotating disc a bell gives exiting paint particles veloctty and directiar. Voltage differential then takes m r and allows etectriiy charged paint particles to attract themselves to a grwnded part.

"Wrap" around effect. waling other surfaces. Works wll with hgh solids coatings. Minimum overspray

Limit to shapes that may be coated. Hgh productm rate required. HQh voltage and spinning cup or disc may be hazardous.

1. URATOMUATION

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TYPICAL SPRAY SYSTEMS

13 PRESSUREFEEDTANK HOOKUP (Extanml atomizatlon)

011 L Wstar

1.1 SIPHON FEED HOOKUP (External atomization)

1.3 PRESSURE FEED TANK HOOKUP (Intenul atomization)

Slphm Cup

1.4 PRESSURE FEED HEATED MATERIAL (ExtomI atomization)

1.5 LOW PRESSURE LOW VOLUME ATOMIZATION (LPLV)

1.6 HIGH VOLUME LOW PRESSURE ATOMIZATION (HVLP)

Fluid Fnssurc lank

2. AIRLESS (Hydraulic atomization)

2.1 AIRLESS ATOMluTlON (Hutod)

Air Suaa1v

uu . . I 8.sk Pmssum Valva

22 AIR ASSISTED AIRLESS ATOMlZATlON

2.3 AIR ASSISTED AIRLESS (Heated)

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Paint Film Defects ~

APPEARANCE CHALKING

Pwdcry coaling on Ihe vlriace of I& pain1 tilm

CHECKING. CRAZING. CRACKING crovioa reprratm Ichccki Irregular line spanlion

Furmnuun l A c dried mud icrxkmpl

Lou of p1-r

~slll$alor chccli

w b c c

FISHEYES. CRATERING

CAUSE Wuthertng ul paint tilms lndficicnt panni apilailan U s of p r l y balanced thrnning d W " l <

In.witic~en1 drying of films prlor IO

mcoriing Ealnme lemperriurc chanpn Cum roo huvy lcheckingi lnpredicnlr n u thoroughly mixed Adding i m p p c r mucrtals

Rccoaimg checked linish Thinner rolicning acrylk i n u r n p i Rut . oil or g m under suriace Moirlvrc in spny line Tnppd rolvenis Eapzmun of film 10 conrlinl or rrperted high humidity

lmpmper w i v e clunrng lmpmpr undercoats Unbalanced thinning wIyent>

lmproperduning of old wrlvc Spraying m r finirhn that conuin sil icm. oil. m o r w e r

t inrmpalibiliiy 1

h r l thinnm an high humsdu? Unbdanced thinncn Cundcnwlmn on d d surface

3VCrKdUClwn E a t n 4~ thinning \dveni* XI burface being painted lmvmxrlr cleaned surfxc

REMEDY &mow pourdcry tilm with A mild pule rbnrive

CDndltWll Sand and rcfinah a chronic fallme

I L m m f inirhdwn IhNvgh Ihc checked pain! film and rchnirh Ux )oIvcm recommcndcd by Ihc punt rmnufaaurer

Sad and ntinirh dimrgrd area)

S'nd and rctinirh dnmrpcd a r m

Wash off p r m while wll WCI

Rub WI hnirh with P prlishtng

Snd and Kfinirh mnpwrnd

Rcmmc lilted surlaco and rcnnirh

Add rcllrdcr IO lhinncr and mprr! %nd d ntinlrh

PREVENTION Apule pin1 thomughl! UX d y Kcamended thmning solvents OT a d d i l m

Thoroughly clean and irwi rubsirale Dram water Imm air i tnn often Thinpmdunspropcrl) A l l w wlfincni drvine iime beiwccn

INCREASING PRODUCTIVITY

IS A FOUR-LETTER WORD

FINISHERS DIRT TO FURNITURE

Isolating the sources of contamination is the h t step m getting dirt under control in fKIing operations.

F o r ~ d o a n u l G f iUshcul thepvl 'S hnd pasawways mm r o l ~ n t Fu m e mum@ ckannp. remove rorrltr and w needles and soak the a n e m areas wipe dorm the exterm 01 the gm mm soivent. bnah and mpe SV " D e r . do not SDak me entire spray gun n wlvdnt. pst &an the affected areas

Plpmo used m air Iims mll ususliy MI of moa as a reWn 01 mOatue laden air entermg the canpenor ll the compesxx uses 04 as a lubncant. chances are as d wears cul. ah. along wm cwdematlon. mll Unmteiy attunulate m the an supply hcs F h t m d e w k K m as 011 and water extractors. must be use3 to renwve lhese n n p n l ~ ~ s lrom the air betore at"- mg the coawg These filters mll remove wbd partculate matter down to 5 m m orless WenwasthelasltmSomeone drained the mislue of totally cleaned oul snd replaced the disposable Mer n the extractcfs7 An examtion 01 meSe hlters mlt tell yw a lot abeut the condmcn ot the an svstem n use Don't l ~ g e t to r6p1?~t the low secbon of the an regulatms (of &'I as well Never lutxicate a regu!atot or extractu - p s t clean them

ma worklng arm. h dirty More often than not. the qxay area 01 a f W e Plant IS a n m but a clean and dni-free mnnronment Good haackeepnp K a must n order to rcduce ds, wntam~- bon Raove &I and pant acummton from wak. (bcrs &ags. m-d Qll la- Mer regularly Pn~W~cally wet down nWrr and walls n and a r m the w a y area to captule and hold dust The tpray boom W i d be properly wsc and e q ~ l p ped mm an aulunatc damper to p e m t back dralts Do rxlt saw M sand n u rear me w a y area kawr gcd n " t K usmp &an. mliaammable papn on me l b ? s n and arand the spray area M t forgel to keep un~Umo(ued pnsornel aR 01 me spray area and spray boom They may be ds, caners

1mprop.r omration of ma rpray booth The owra lm of a spray boom IS a mpk ConCePt its purpose K to exhaust I w s and overspray away I ran the spray opera tor and hnished pan However as me air IS reptaced there IS a teMency to draw dtrt mto the lx" from wrrDvnding areas n a w a y boom telles cn unhllered rnop ar as its an swce. men din m the hrush may never be mder COntIOl

One soidon 15 to emlose the booth ard use s~eual Intake hlters to remove the dirt belore it enters the spray area These hI- ters must be kept clean and should be me ~ecanmended type Ch some booms mese Inlake hltefs are cn the main 03M5 mlcn o w to allow the pans to be k q h t n a m wi

~ , ~ ~ m u s l t e ~

cul Q a d r m C ~ o f h c x l u a k ~ mfsbywyng ascnppn. and h l e It S SWI Wet. PrSU d drsCtly *I the make-up u Ibw Then. " c t d for dirt Otten nbratlom n the bruldinp or from bocm Ccus mll allow sure din to escape hm hcre Men and mto the fmsh When m dcubt. rwlace thasc Anen

The deal h~lulm n any spray m m K to have an mdepadsnt lwced an make up system tor your encloKd boom The air eemanded by tkd booth comes lrom a =parate aw replacement vw( wixh pcr ndes the unect m t 01 heated M

p l y q a m 10 percent m e air nto the booth man IS beinp exhawsted. a poslhve paaue mll ds~elop hat and dirt mll not enter wn rrmce doors are opened of hrwph seam and cracks 01 Me structure hstead they mll be forced away

Ma~pemmt may want 10 contldn svvltchmg to an e k t m a t c hnlshtnp system when pracbcal Donp so allows a 40 percent reducten of the amount 01 exhast at! requned by the 0ccupalional Salety and Health Admrustram Not my mll thls draw ~ n s a t and 6n mrwphtwi me spayarea b u l a ~ a i w s a v e o n m e avm'r haw and coolinp bilk and c m W emw01-6 and redm costing co51s

Don't OW the "riame 01 the exhast fiiim H IS an OSHA rcpulatun mat an 6, finer spray booms have a ww.1 p i g e or maTyyM)ter. ndicatiq when It e WU to change the exham Mters Tho draft gauw measures air resistance tha@meFdle!sWnoperatm Not cnly K 0 &gal to untrme to operate a boom mm the filters LXVW their capacity bul it a h u n ~ t e s t o dul m me fmnh

poor oporator tochnlqua The operator WM sprays mm ex- pcuues 01 excetsrvs Ian patters wiU untrlbute lar!piy to &st and overspray n the boom IMQ proper apraytrq tech rnques WII put m e of the coahng cm me pDdut and less on the walk lkcf. bases. extractors. etc Eventually mo dned mate- MI wdl Wodpe from tnese Uaces and m u p a s dKI n me hnrsh

sues K to always use the lowest DfeSSWeS mat will rwn n a satslactcq spay pattern The operator can improve Ius tech N Q U ~ by controllng these five vanabk

mainminng me pcper dsIance be weenme gun and the work.

ovefIapping each pecediq stroke by 50 Percent. 0 keeplnp the pun perpendrcular 10 the w&.

mamtaimng thc wnett gun movement. and

trmring the gun betote and after each pa=

Mula tplw IW U s system to keep dul

c&Sd au wtuchKatJofWed By S u p

A 9pod rule to follow when Setting pes-

17

Mhouph it M y te unwssible to control lhese a r u m s a11 the mn. try to teach gcca habits to w a y pctmnei m wotr to reduce reject.% AnomCr pood &a IS to nan sMayiq

areas of the praduct farlhest lrom the exhaust Ian. TI% w m i ~ the overspray and onspray to move wim the air I!OW over mnmtshea Maces mto the exhaust.

Dlrt and lint on tho clothing IS often overbked. M ckny overalls

mm dust and Imt m cuffs. pockets. etc.. may destroy a perlect I". Disposable or wash and wear overalb made 01 an ana- static matenal may be necessary to control din n the finsh. Many operattons are r o w prowdinp sprayers mth paper crommg.

strue .Iectflclly electrluty IS often hard to accept as

a culpit in the hishmp rcinn. Static elec- Wily. erpeclally when me humidity is low. will amact h o t parlicks like a macnet. Stabc newvaluers of eliminators may be requited. especial$ when s p a y q plastic pam. Tha best way to conuol statlc elec- mny is to neuualue M g~ound au e k t r r calk conductive objects m the spray booth. T ~ I S includes the pan. the spray boom. the unveyu. the w m hoiders. and don't fofcet. the sprayer.

The sprayer is gcweed by homg the way gm h the owfatot's bare hand. A" way IS to use cOMUttlve air a m Ikud W s m the system. h ' t l o r p i 10 Drounj thc matenal w p l y pump wim a pornd mre:

Funlture mohen may fnd it IS almost impcasMc to cnmpktely eliminate din in the frrsh. kR by lollowinp some 01 me atow recommendatm. my S W d . at bast. be aMe to get it under control

yar matenal wpller as well as your e q U l W t WrpplnW VI order 10 fight con- tarrmatun of your fintsnea Drffluct Don't omlook the pwrbiltty 01 payins an IC&.

hshnp cmttant to examine me Wnl's fauship operaton. Not only will he be aMe to troubleshocl the din problem. bul he can show you how to improve me overall applicatm enrlency as well.

!

n waddbe very ww to ask the help 01

FINISHING

VIScosm Briefly, thc viscosity of a mutrial is an indicaticm of its ability to rrri,r flow. The now characteristics of liquids relate directly to the degree of internal friction, therefore, uything that will influence the internal friction (such as solvents- thinners-or temperature change) will influence flow. Simi- Lily. it is the flow characteristics that determine how well a material will atomize. how well it will "flow out" on the work. and the lype of equipment necusary to mow it. Viscosity control, therefore. is essential in obtaining a uniform &ish quality fmm day to day or job to job. Your material supplier will recommend the best viscosity 10 apply the material chosen for your job-stick with it. There arc many methods by which viscosity determinations are made and each method may have one or more units of measurement: I . The measurement of resistance to movement of a device

through the material in a rotary maim (such L( a paddle or fork). is expressed in Krebs Units (KUS).

2. The resistance offered by the material to a falling body passing through it. usually a ball of specific size and weight. is Poise or Centipoise (100 poises).

3. The lime necessary for an air bubble to rise through a quantity of the material in a tube is the Gardncr-Holt Bubble Method.

4. The time necessary lor a given quantity of thc nutcrirl to flow through M orifice of a specific size in thc batan of a special cup is thc Efflux Method.

The paint user will find the EFFLUX Method (14) the most ;enerally employed. Bah Zlhn ud Ford cups are available with different size orifices to p i d e a wide nngc'of viscosity measurements. However. the two most widely used for print are he zrhn #2 and Ihc Ford #4.

EOUIPMENT Viscosity cup. stopwatch. ucaroria as illusmted. PROCEDURE I . Rcplrr merial to be tested. Mix. suain, ctc. 2. Insure that cup is dean and orifice is free of residual dried

3. Raise (or h e r ) temperature of test material to standard murial.

I d (ll deg. F nxanmcndcd). 4. Fill cup:

a. khn-submerge cup in material. b. Ford-Pour material from container into cup until it

overflows into surrounding reservoir while simul- tanmusly holding a linger at the orifice IO prevent flowout. Place conuim under cup.

5. Release flow of material and simuluncously trigger stop watch. Keq eyes on the flow, nu the watch. a. Zlhn-Raise cup out of the material. vertically, by

b. Ford-With quick movement remove finger from

6. When solid stream of material pouring from orifice 'brutr" (indicating p w g e of sir through orifice). slop the vuch.

7. Record slopwnch elapsed time, e.&. 20 xcads . No. 2 wn.

8. Rcfer to the ctun (opposite page). 10 determine viscosity fclatedtoclpedtimc. --/

IYlmns of split key ring.

mi6a

18

VISCOSITY CONVERSION CHART FOR MATERIALS AT 77" E WITHOUT SPECIAL THIXOTROPIC CHARACTERISTICS

HEAVY CONSISTENCY Fluffy cream or slow pouring syrup type materials with medium lo coarse mind color

MEDIUM CONSISTENCY

Light creamy or thin syrup t y ~ materials I lucent or very line grind mlor. I with medium to fine color or filler orind.

L IGHT CONSISTENCY

Watery or light oil IVIK malerials with trans-

CAUTION Your ~iscosimeter i s a precision instrument requiring careful handling, cleaning, and storage. Improper care will adversely affect i t s accuracy.

Compressed air spray gun principles

1 GENERAL DESCRIPTION OF AN AIR ATOMIZING SPRAY GUN ~- The b i c function of an air atomizing spray gun ir to use compressed air to break up material into s m d droplets and give these droplets direction. The spray gun itself rovides taro convenient valves to start and ntop t ie flow of com ressed air and fluid. The mixing of air and m a t e d m take lace outside the s ray g u n between the "horns" o P the air nozzle. T?h is is described as "external mix atomization". If the mixinn of air and material rpkes dace inside the a i r nozzh of the y a y gun. we 'use the term, "intemd mix nozzle . Material can be brought to the spray gun by creating a vacuum at the face of a siphon type extemd mix nozzle. This vacuum draws the material through a tube coming from an open top m a t e d container to the air nozzle of the spray gun for atomL0tian. This method of atomizPtion and material delivery is d e d *si hon spraying". See Fig. Y1. When heavier fluids or !&her production rates are requirrd. the material can be pressurized and forced up to the air n o d e for atomization. This method is then called "pressure feed Sprayhf.

- I

n. SPRAY GUN SELECTION The selection of a spray gun is determined by its function or end use. The most common t y p e s of air atomizing spray guns and their. features are listed beloar. A. Heavy Duty Production Spray Guns:

1. High volume of materid output, 2 Rugged construction. 3. Must be able to handle a wide range of materials, 4. Rovide the widest range of controls. 6. E w of operation, 6. Modular design of components.

B. Standard Production Spray Guns: 1. Performs the m e as heavy production spray

guns; normally tokes the same air and fluid

2. Lighter construction

1. Light weight, 2. Light construction. 3. Handle only light materials, 4. Small physical nize.

D. Heavy Fluid S p y Guns: 1. Rugged ermrtruetim, 2 High apreity nodes, 3. Handle heavy materials.

1. h e requirements and nodes as for produc-

2 Spray gun is operated by remote mtrol.

nozzles,

C. TouCh-Up Spray Guns:

E. Automatic Spray Guns:

tion type sprny guns listed plwiwsly,

F. Special Purpose Spray Guns: 1. Air blow guns, 2 Caranshingguns. 3. En* dealling guns, 4. Rold muking,

7. Flock spray guns,

6. Extension pole guns, 6. Flora guns,

8. Plural component spray guns. G. Special Spray Gun Attachments:

1. Fluid strainers, 2. CirmLting connections. 3. N o d e extensions, 4. Extension arms.

20

A

B

C

D

E

F

G

H I

J

ni. mms of A SPRAY GUN The basic parts of a modem production spray gun are outlined as follows: Item Description

The air nouk of a S D ~ Y run is the most im- . _ - portant part of the entire spray gun. The air n o d e directs air jets to ptomim tbe Buid and to give the particles velocity to reach the product surface. Thtprrid nouk is the a e c d m a t i " (mt part of a spray gun, for this part pmvidea a mhl for metering matvinl delimy. Needle assembly acts aa a s t o g s u r t valve for the mated flow thmugh the s p n y gun in emjunction with the duid n d . sidc porl tonhol or fan control reguhtas the spray pattern width by controlling the air supply to the % o m " of the air d e . Fluid control aasembly pmvidas mechanical pressure on the needle valve so that it will dose when the trigger is released. The m y gun body hod& is deaigned fa hold d the oprts and mve the owntorahnlanmi and cothonpble L d l e for-sprayiug. Air inlet to provide a connecting point for the air hose. nonnallv 114 in. N.P.S. Triggcrectivatds and controls the air and material movement to the nodes. The air valve controls t he air movement through the spray gun. Fluid inlef connecting point for siphon cup or material hose. normnllv 318 in. N.P.S.

The versatilit? of using compressed air to atomize material has made this type of spray gun the main means of applying a mating in the hishing industry today. These spray guns can handle all types of sprayable liquid materials and can be controlled to such a degree as to pmluce the hest possible 6nish on a product, with lowest possible equipment cost. This type of spray gun is a precision tool. The rpray operating efficiency is dependent upon a knowledge of proper s p r q gun selection, spraying techniques and maintenance.

W. SPRAY GUN DESIGN A. Bleeder or non-bleeder type spray gun. Most

production spray guna are non-bleeder type. Air flow thmu h spray gun only by the action of the

used with d portable air mnpreMor to maintain eonatant pressure, and prevent the pol- aibility of rtOrtiag up tbt compresror against a load. Air discharges from the air nozzle continuously.

B. CMStruction Features: 1. Removable head, 2 M d g e type valve rssemhlies, 3. Adjutable needle .ssembly, 4. Triggw bearings and a wear plate.

Gun: 1. utr", 2 Bnss, 3. st.inless steel.

1. Drop forging, 2. Die asting, 3. h g h ensting.

1. Weight, 2 Location of controls ( h t or rear of spray gun), 3. Handling ehpReteristics, 1. BPLnce.

1. Number of pnru, 2 Ease of air flow through spray gun (pressure

3. Air nozzle and 5uid n o d e desim.

trigger. B 'i eeder type spray guns are normally

,

C. bterid Used In Tbe Gmatruction Of The Spray

D. Method of Construction:

E. Spray OpeRtms Features:

F. Design Features:

drop), -

4. Protective finish. 5. TvDe of material used in construction of fluid

~ ~ _ . Compare these points to the expected service one may receive as compared to the initial cost of the spray gun Seleaed.

21

V. UR NOOLES

porig: A. Airspnypm n d u fall into tkfolla6iingate

AIR NOZZLES

i r EXTERNAL 1 SIPHON FEED PRESSURE FEED

B. The control and operation of these air nozzles depend on many factha such u: 1. Pmper trpe of air n d e , 2 The 8k.e selected, 3. SPnY gun d. 4. Method of feeding m a t e d to the n d w . 6. Material to be sprayed. 6. Setting of p r e s ~ ~ r r s air and fluid, 7. Adjustment of spray gun controls.

The most common type of air n o d e used today is the external mix node . The reason for ita wide acceptance is that it will produce the best atomization which, if controlled properly, wiU gin p u the best possible finish. These air nozzles u e

C. External Mix Air Node.

designed~to put compressed air to work in the following m e r 1. The annular ring, the space between the fluid

nozzle and the air n o d e , provides a column of air to s m d the fluid stream. (See Fig. A-1).

2. The fluid 6tream expands and mixes with the air coming from the annular ring of the air nozzle. This is d e d first r b g c atomization.

3. The holes which we in a straight line with the “wings”, “ears” or “horns” of the air nozzle are containment holes (See Fig. A-2). a To keep the spray pattern f” expanding

b. To keep the %oms” dean. too rut.

22

4. On p m u u m feed air noules, a second set of holei may be indexed 90’ from the containment holes. Theae holes are called angular converging holes. This i, &led second stage atomization. (See Fig. A 4 , these air pas- -a d d additional force to help atomize the duid stream since in a pressure system. the fluid comes aut of the n o d e at a higher velocity than a siphon sptem. The air mmment a t thia point, creates an air cushion at the face of thc nozzle; thh helps to keep the face of the air d e dun.

6. The air piwagmap in the “horns” (sometime all4 ”wings” or uears”h are d e d side port jeb. (See Fig. A-3).

6. The side port j e t s of air, strikes the fluid stream just ahead of the second stage atomization point. The primary purpose of these

rt air jets is to form or shape the air ?%Kid stream into a “fan” shape. Some additional atomization may nlso result.

7. The &e of the “fan” width a n be controlled by regulating the amount of air diverted to the side-port je ts (See Fig. B, Side Port Cootrol Stem).

FIGURE A - EXTERNAL MIX ATOMIZING HOLES SIDC.COR?

COUTROLKNOW

0 ANNULAR RING ARWNO THE FLUID NCZZU TIP.

@ *‘CONTAINMENT MOLES” @ ‘WNCS“. “HORNS’* OR ”EARS” @ SIDE*PORT HOLES @ ANGULAR CWVERGING HOLES

D. The Evolution Of An Extend Mi Air Nozzle spray Pattem.

The above illustration represents the evolution of a spray pattern h m "round" to "fan". Assum- ing that the fluid and air pressures remain constant for aIl the patterns, the mwt of fluid deposited in each instance will remain constant. "Ius, it can be noted that as the area of the pattern increpses, the fluid fiLn coating thidmess must deerense. The duid film coating (or fluid deposit) is measured as mil thickness (1 mil equals .001 inches). For example, if the pattern on the extreme left hns an area of .800 square inches and a thicknw coating of 4 mils, the pattern on the extreme right with an area of 1,600 square inches will have a thickness mating of 2. mils. Gencrplly, proper atomizn- tion can be achieved in any pattern, dthatgh with some nozzles and fluids. minute adjustments of fluid and air pressure may be necessary since more overspray and solvent flash-off will occur with the fan pattern thu, with themud putern. Since this fluid is 'lost" and not deposited on the surface being ~ p ~ y e d , n c t d 5lm thickness in di cases should be determined by measurement. Also a dry Alm will memure leu than a m t 5lm because only the "solids" remain after the solvents have enprated in drying.

E. Determining Siphon And PRsSure Feed Extend Mix Air Nodes. External mix air nozzles break down into tam types. They are either siphon or pressure feed. The siphon feed n o d e can be determined by the fluid n o d e protruding beyund the face of the air nozzle. The angle at which the side port jet holes are drilled in a siphon n o d e is different from that in a pressure nozzle because a vacuum must be created at.the face of the siphon air n d e . (See illusvations at right) .

Pressure nozzles can and s h d d be used with lmer atomizing air pressure since the vacuum condition is not required as in the case of the siphon node. Pressure spraying is more efficient, faster and cleaner. Siphon spraying is best suited when s d quantities of materkl are being used such as in an automotiw body shop. Resure feed &e horns are shorter and the face hns additional air holes to help keep the face of the nozzle clean. The side port jet angles can be drilled at a closer angle be cause no vacuum must be created at the face of the pressure feed node . The numbering designa- tion will indicate whether or not they are siphon or presIurr ~ o r ~ l e s by the letters "S" or " P stamped 3:. the node .

SIPYON

F. Requirements. Advantages And Limitations For External Mix Nodes. 1. Equipment requirements. a An air supply capakde of meeting the repuire-

ments of the air nozzle. There a r e many different types of external mix air nozzles available. These nozzles difIer by the amount of air they consume, spray pattern size and materials they uill atomize. Sales literature and engineering data must be checked for

23

thlinlomstim b. The sLr no& m& be dedi& for liphm m for praanac rpnying.

c Pressure feed nozzles require that the material be supplied under pres." to the s p n y P.

d. Pressure feed nozzles omnot be wed for dphon feed spmyinp.

e. Siphm feed nodes can be used for prranm apraying hut the spray patem drc wi l l k smaller. Siphon feed nozzles are often used tor p~surr feed &g of sdbwivea.

ExtunJmixnoszlasernpmdueethe~oest possible hi&. mnldng it ideal for furniture Md epT finishing.

b. This air nozzle baa great flexibility in eon- bullingthe spmypattemsize and thedegree of paint u0"L

c A siphon nozzle can be us€d for drawing motelinl hum a container and atomizing it.

2 Mvmt.gas.

3. Limitations. a. Theyrequirelnrger~titieaofair. b. Tbeyoprpteunlntivelyhighair~. e. They maycreate large amounts of over- . spray a d rebound if air md flnid pressure

-e+Y-.

VI. INTERNAL MIX AIR NOZZLES In M intend mix air nomle or l w preasrne &e, air and fluid a r e mixed in a cavity inside the air nozzle before being released to the atmosphere. These air n o d e s have eitber s round hole or a slot from which the mated sprays. When tbe mate4 lesrns the air n o d e it will "fsn cut"sndumf0rm toa ahape as determined by the air node ope*.

INTERNAL nix AIR NOZZLE

nozdea do not produce very 5ne atomization but bvc bigb production apabiitiea and am Nitable for mwt msintcmn punting work. Not dl materide un be sprayed taith thin type of nozzle. They are limited to dower drying materials becruse fast dqing matednh tend to plug the exit bole. A. The equipment requirements, advantages and limitstiia~ for intend mix air node pre: I. E&"t Rqimmta:

a. Thin type of air nozzle can only be used witb a premre feed system.

h. The nozzle requires the use of low air and duid p r r s w t k

c Tbe lir and 5uid pressures must be closely rrgul.ted.

d. The air .ad fluid preu8w-e mt be appmx- W y equal ai tbe node .

e. Intemd mix n o d e s are available in many rizes and constructed of many types of mate* the choice is dependent upon the kind of materid you arish to spray and the rate at wbihieh p~ wish to apply it. (Refer to dcs .ad enginering bulletins for selection daw.

2 Advantages. a. Lorp volume air emsumptian (cubic feet per

b. Lorpsirpraaure(paundspersqunrrinch), c By ruing law air p ~ a s u r r and fluid pmsure

tbemrapmy or rebound will k minimal, d. clp.bsity of higb Rtc of fluid cutput, e. Cm produce Lge spray pattenul. t Hw the ability to break up heavy, filled

moterkb, g. Noarle tip can be replaced at low east.

8. Limitrtioas: a. Thia sir n o d e produees coarse atomhtion

and is not recommended for extra fine -9

b. Some fast drying fluids have a tendency to dog tbe exit slot or bole,

e. Tbere is no control except by n o d e selec- lim for the spray ppttem size or shape.

d. Noak wesm due to abrasion. Tips must be rrplsced.

B. Stutup proeedurc fw internal mix sir nozzle. For maximum efficiency, both the fluid pressure and the air pressure should be the same at the nozzle. To initially adjust, always start with the air p m u r e . Tben dwly Rise the fluid pressure, gradually lowering rhe air pressure until the desired flow rate and spray is reached. NEVER open tbe duid valve &ut, since without air atomization pressure. the fluid will tend t o back up into the air psaages of the gun.

minute).

These air n d e s find wide acceptance in the maintenance psinting market for applying mating to Lge s reas very rspidly. These internal mix .a i r

24

M. S P E C U E F F E C T U NOaLES specid rffect l l r Wrrles ue gelnnlly prrawe fed These nouls are upd to meate rpckl effectr rlth certdn types of mrtnirk by using extremely low ah mi fluid p m s u m which have been accuntely COP

trolled. These spedd effects .I( m d y sprayed to a t e exotk type rlndom rpng patterm mch n wiling. iprtter and dWeadng (sometimes called "fly

changeable with d.adud production spny pas No rpeid cpny p n LC requlrrd

A. Eguipment Requizemnu:

rpeeking"). Th- MZZlS UC M h b k Md &tW-

1. A specid mix nozzle kit for the tjp of effect you want to achieve, mounted in your rpny

2 Two air ~ e g ~ h t ~ ~ for precis control of both

3. A one or two quut p n w r e cup, or pressure Unk. depending on the amount of material that is required to be sprayed.

Iun,

lir lnd fluid preasums is required.

B. Advmtapa: 1. The ability to n u s produce a rpeid effect, 2 Added rsles appeal to a product, 3. Hiding ibUlty to cover defect&

The spray opentor must be more highly skilled when applying these eftear. in order to iru&Wn @me uniformity.

C. Limitations:

WII. PROPER AIR NOZZLE SELECTION . A The following points must be *en into oonridm.

tion when m k a i an ah n d e :

1. The type of matexid you M Eoingto spray will determine the spny pattern size .n well u how it atomize& B w u w diffmnt nvtcrkls rill cheu or tea^ spur according to their cohaivr

2 The volume of air you have available In C.F.b!.- not prasure. Do not choose UI air wale r l t h a cubic foot per minute r a t i i wbich k luger than that which your mmpnsor a n supply. A ruleof thumb you a n foilow is that a one home power electric mL0r driven comprrsDr W~II provide four cubic feet of .ir per minute at a hundred pounds per square inch

3. All air nozzles will not physically flt over Iu fluid nozzles so it b nerrs6vp to select thee item LI I matched set. hpr nutching of air and fluid nozzles mud be checked out on a chat propided by the equipment mlnufictum which shows 111 avallable mmbirutiow

4. The higher the C.F.M. rating of M air nozzle, the m a t e r the volume of matn*l that the air nozzle k upable of atomizing.

N I U R .

Siphon and wmura mzzln .milable

LIMITATIONS Rquira mors C.F.M. 01 air Worbwrirh hi$! air pmure only Hximum onnpav Minimum lilm build P Pfl U n i r " size rpw m6Il

L Thaefote an .It nonle with a larger C.F.M. rating wP1 provide a fwer nt. of application of the uumiJ on the Nbrtnte.

b. The &her the Ilr pi- i t which the air mt2k must operate, the mter the air

l n o a a . rir volume (C.F.M.) re. putted llm Lacrgwr

Rmurs f n d only

ADVANTAGES Rquiri 1 6 s C.F.M. of air Rqui rn low air P.uuII Minimum owmcay hbiimum film build PIPE hiin'" size I P ~ V p n n n

EXTERNAL MIX INTERNAL MIX AIR NOZZLF. n AIR NOZZLE

r

ADVAMAOES LIMITATIONS Coaru atomtauon Fixd m y pnnn

Fim Atomiution Control of spay p n r n

.U*

Fluid N e t d m 0 1 H k s Rang# Idnmtn)

.022-.028

.w .o52

.059-.070

.o86.110

.115.5w

Air m I a t i p will v m r

v i w U.

VIV Thin A C n O M Thin Water

h i l u m 5 A E No. 10 oil Hrrl SAE No. K ) oil

v w b v y VSChnC

25

4. TO d e t w i n e nuid now nt. for p-m fw spriylnl, &ut off the itomiring air and puU the rpny gun triggn to bleed the nuid Into a graduated container for OM minute. The following flow nte chuI for i 20 rcond mta*l wing I number 4 Ford cup, tt t ternpentwe of 75oF, m y be of some help In pndkting now ntar

Delivery in Ounca Pn Minuta

.059 24.0 3l.O 40.0 28.0 48.0

5. For i more =curate reading of fluid delivery and prcrsurr i t the inlet of a rpriy gun for i puticulu size fluid wzzk otUice i t i certain IMtRirl viscosity, the following folu c h u t ~ showing the most common &e nuid nozzle orifices used will be of ulstanca, To use theae graphs one must measure tbe fluid d d i r a y and riscohity to find out the pr- i t the inlet of the spray gun When the rqulnd delivery b known for i particukr vimsity mitdul, the fluid plegurr rad nuid nozzle oriflee dzc in i spray gun a n be determined by drawing &sight lines connecting the known nlua to find the unknown dues. Example. wb.1 &e fluid nozzle will give i 28 fluid 02. per min delivery i t 12 P.S.I. fluid prrrsum with 4 15 m n d material? Answer.052 om-.

6. Material from which the nuid nozzle k m d e will nry depending on the ehurc(crlLia of the fluid to be sprayed: L SUndud p h t s use hardened rbcl norrla. b. Corroave mtnws (water hued, 4- etc.)

c Abrrzivc materials (mamkr. etc.) use tung-

*

use Iwnles steel nozzles

sten arbide quipped w a k C. Control of nuid flow:

1. Siphonspraying. L The nuid noa le orifice. h. The idjuament of the nuid control on the

L The nuid nozzle orifice. b. The nuid presure setting. Note: Not to ex.

ceed 18 P.S.I. i t the spray gun inlet for standard type of materials, excesive nuid pressure causes high fluid velocities which prevent the lir nozzle from itomking the nuterial properly. Always ur the west possible nuid nozzle orifce urd the low& possibiefluid pressure to give you the mrteri- aI delivery you require.

E. The adjustment of the fluid control knob on the spray gun should be in the maximum open position on I pressure feed systems This is just about that point where the screw threads appear on the nuid wntml knob. The nuid control knob is the irrt Item tht is adjusted for fluid delivery.

"Y gun. 2. Reswrerpnying.

d. A NIU of thumb t h t a n be followed with clandud rmterbk wben rtting resum k t h t rlth the rL ~ p p l y cut off the p i n t rill flow In i mlld acma T h t fluid strum lhouid begin to bend down ahout thm feet from the spray pa Anyrbl In m e % of thm fwt mu Loo higb i%id velocity. (see r i m below).

X. NEEDLE ASSEMBLY The bu ic function of the needle is to shut off the h i d flow. It rL0 can be wed to meter the makrinl pming thmugh the fluid no&. (c2s above) Needle lelcaim t bwd m: 1. Th &le must be nude of the proper mpterid

and the right *Le to match the fluid nouie. L Standard needles i r e corrosion resistant.

b. Abrasive resktant needles ue tungsten car-

c. Needies which require positive shut ofr u e

2 Tbc d e is part of amrtrhed et urd if not the ight *Le it aill caw problem: L Leak at tbe h i d n d e . b. Split the d of the fluid node. c. Turnmtbeduidheforetherir. d E x d n prorwion of the needle tip which

rill mIrkt fluid deli-, e. A nqcdk tip which Q too *rge will not dun

out tbe fluid d e sri5n when luted. 3. Needle idjultment is mquimd on certain spray

gum to compensate for wear. The adjustment is accomplished by changing the position of the lboulder .nd locking nu& (See right band figure belW.) a. Determine the amount of adjustment re.

qulcd-lund guns should hove an ur stroke of 3132 of an inch (ipprox.) and automatic 8pny gum .bout 1/16 of an inch (see figures helm).

h. Looren the lock nut and move the shoulder forayd to shorten the air stroke or rearward to kng'tben the stroke. Try the needle in the r p n Y gun.

c. Adjustment is by trial and ermr-when correct position is found tighten the lock nut to hold the shoulder nut.

huded stainless &el.

bide tippd.

nude of nylon.

1/16'.

26

XI. SPRAY GUN CONTROLS A. Operator Spraying Techolqua

The ntrr ? q u i z " Y propa handling of tbe spny pa The spray p a should be held papen- dieulu to the ruzfece being covered. and movd In even s troke p a d e l with the ruzfrec. The stroke rhould be stuted kfore the tzigger k pulled Md reluvd belore the stroke k flnkhed. Thk is easy ud gives accurate control of the ~ p m y p n and m t e W The distance the spray gun is held I" d a c e is determined by the materid a d a t o m . tion praacre, and may wry from 6 to 12 lncbq but the material deposited should always be om ud wet. Overlap each stmke by 50 per cent over tbe preceding stroke to ohmin a unlform llnih For additional information on rpnyitq techniques see Training Divkion Bulletin No. TD49.1 per. taining to this subject

WRONG

RIGHT

E. Adjustment of Spray Gun Controls a. The proper adjustment of spray gun controls

permit a spray operator to control the size of the rpny pattern and the m o u n t of material coming out of the spray gun

h. The spray gun controls will he louted on most spray guns in one of the three following positions:

Spmy -,I+ odiu.tn.nt. Turn v q h t for round. 1.h lor Ion

Ya.*i.l cmnw I.2I.l.

Spray * width

*i""lM"I.

C. Siphon Spraying. Set atomhtion pressure at appmxinutely 25 P.S.I. and kst spray pattern with fluid control knob opened. If material atomization k tea come, in. crease air pressure by 10 P A L and est spny pattan 4Jn Continue this untll you have 50 to 60 P.S.I. at the spray p n If material rtomiwtion is ctii too muse dose (turn dockwise) the fluid control knob on the spny gun slightly. Adjust the rpny pattern width and repeat adjustment until a proper spray pattern is achieved using the lowest possible ah premtre that will produce the desired fin& Additional thinning of material m y a h be WUind.

D. Rnarre Spray@ Select conect fiuid n o d e orifice size using the previous fluid nozzle seiectin charts and set nuid presure for required materid delivery. Set atomi. a t ion air at about 25 P S I . and test spray pattern. If spray pttern is too come, n*e ah prepsure. Adjust desired spray pattern width, repeat spray gun adjustments and nuid pressure fating if n m s u y . In some inrtuKes material m y require addltbnd thinning. Remember keep fluid control mew in "open" position Use mmct fluid nozzle size and pmper fluid pressure setting to obtain pmper flyid delivery. NOTE: To reduce "over. spray" and obtain muimum efflciency. always spray with the lowest posihle atomization air pressure and the lowest possible fluid presrure that will give y w the required finish you ue seeking.

The spray panem of M external mix nozzle on a spray gun quipped with a fan control k variable from rwnd to fan with all spny patterns in between

E. Spray httm

In normal operation, the wings on the nozzle are positioned horizonrally IS illustrated here. Thic provides a verticai ~UI shape spny pattern which gives maximum coverage IS the spray gun is moved hack and forth pmliel to the wrface being

27

M. S P W Y GUN INSTALLATIONS There uc nuny ways in which a apny p n CUI k in-

amount of material )w wish to sptay, che fluid viscosity and the atomizing air MI haw ~ i l a b l e . SIPHON FEED HOOKUP For limiud spraying md toudwp. Atomization air is Icgulated at exmaor. Amount of fluid and alomiutitm is adjusted by fluid contcol ccmw on gun. cmsiamcy of paint ud air presuuc.

lulled .nd used. Ihe rynun I c l d will *nd on the

PRESSURE FEED CUP HOOKUP Atomization air is regulated at exmc~or. Fluid p m ~ ~ r e at cup regulator. Atomization air pas= thmugh cup replator. T h i s method is ideal for fine finishing with limited spraying. Pressure cup also available las cup Icgulator. Fluid pm- SUR q u a l to atomization pressure. For heavy fluids ud internal mix nozzle spraying, fluid adjuned by conml screw on gun.

PRESSURE FEED TANK HOOKUP (Si& R r g h o r ) Atomization ur is regulated .t exa-". Fluid pressure at tank regulator. This system is ideal for medium productm spraytng.

PRESSURE FEED TANK HOOKUP (Double Regulaior) Atomizatioi6 air and fluid pressure is regulated by two individual air regulators on unk. This is proven highly efficient for portable painting operations.

PRESSURE FEED CIRCULATING SYSTEM HOOKUP Atomization air rcguhtcd at extractor. Ruid pressure regulated at nuid regula~or. Recommended for heavy

INITIALLY-Always prepare paint to be sprayed in accordmce with MnnuJncrurrr's Insrrucrionr. Material should always bc h n e d h.

F" s*.

. .".I E

PRESSURE FEED INTERNAL MIX NOZZLE SET LIP For maximum efficiency. nuid and air pressure should k idendul at the nozzle. To set up chis caditton easily. Jwys introduce air p s u r r fim. Then. slowly inuoduce fluid pressure while simultaneously lowcring air pmsurc until UK desired flw rau and spray p a " are achieved. " E R introduce fluid pressure first since, without air pmsure. fluid will back up into.the air passages of the guo and caw subsequent malfunaioning.

XIII. MAINTENANCE PROCEDURES FOR THE AIR NOZUE. FLUID NO=€ AND NEEDLE ASSEMBLY

A. All air nozzles, fluid nozzles and aecdla. regardlas of he i r cost, LIC prccisicn made and care must be

' taken when handling thcw puu. 1. Do nol makc m y Illeratioar. howcwr slight; these

could Uuy finishing difficultia (with the exception of d l e adjuament).

2. To dun air and fluid nozzles. soak the parts in rolvcnt to dissolvc the dried material on them and blow dean with air only.

3. Do nu probe m y of the holes of the nozzles wth mcul insnuments. If you feel probing is necessary. w mly I tool that is softer than brass.

4. The needle assembly m u be adjusted so that the lir turns on bcfore the fluid docs.

8. To chcck out a spray gun properly and be certain that the air and fluid nozzle uc functioning correctly. a sene$ of spray panem checks should bc made. Stan by opening the side port control io the maximum open position. Turn on the air supply using B h air pressure setting. then turn on the fluid supply if needed. In- crease air pressure in 5 P.S.I. increments until che de. sired spray pattern is created. Increase fluid prcrsulr slwly if needed to hel,p balance out the spray pattern. Trigger the spray gun in short bums on a dean surface and wtch the spray pattern lake shape. (See Page 41.

TYPICAL FAULTY AIR NOZZLE SPRAY PATTERNS

RtfWl cluu

1. Drld paint in ow of the dde port bola of air male.

cmlction I 1. DMive print in dde pod hole with

thinner; do not probe iu any of the bola with a tool buder than brui.

.I e”’? -9 e:*:- ‘- c,, -‘.

1. Fluid build up on side of fluid mule.

2 D u ~ p a d fluid wuk b u m spny v drop@.

Lhprrrurrtoobu. 2 Spny pattern too ride. I 8. Fluid n l c a u ~ too low.

I fluid ... . ... I

~

1. Remove llr m a l e and rip male.

2 Replace damaged fluid mnle .

1. Reduce rir pressure. 2. Reduce fan width.

2 Usesmrlln fluid nozzle n r l l i , lower fluid mcuuw.

1. Air mtahg tbe fluid supply could be auaed by: L Loor fluid nozzle, or mt sating

pmpedy due to dbt. b. Loose or missing packing nut or

dried nuid packing. E Fluid connection l-.

L Tahten fluid wzzk. or dun fluid nozzle 8eat area.

b. Tighten packing nut. or replace missing or dried fluid packing.

E Tighten 111 fluid supply mnnec- tions Inding to m n y gun.

XIV. GENERAL MAINTENANCE PROCEDURES FOR SPRAY GUN A. Pointers on cleaning a apny gun

When a spny gun b umd r i t b a riphon cup. thinner or suihble alvent should be dpboned through the spray gun by inserting t h cup tube into an o p n top container of that wlvent. “rigger repeatedly to thoroughly nu& the pastageway and c l a n the tlp of tbe needle. Ckani~rpraygun used with ap- t0-m

b. It dissolves the lubriatlon on the spray gun awing the purr to wear Iura.

L It causes dbt or rolkds to build up or become bose In the dr pasages wbicb will m n t i m h t e tbe linkb.

6 It h p h thc opntion of the spray gun. 4. Wash down the outside of the equipment with

mlvent dampened rag%

n n t on t.+ and l o o m air nozzle. Hold a pi& of v l h L- clotb wadded in tbe hand over the llr nozzle and pull the trigger. The llr wlu back up through tbe nuid nozzle and force the fluid in tbe hose back into the t.d (mmetimes r d e m d to as ”blowing back”). Next, put enough clean thinner or solvent into the tar& to wash the inmior of tbe bore and spray gun thoroughly and spray this througb the spray gun until it NN clean.

B. NOTE: It ic extremely poor pnctice to h m e m the entire spray gun in thinner. When this is done, the mlvent removes the oil In the leather packings and causes the spray gun to “spit and leak”. 1. Immerse the rpray gun herd untll the solvent

just covets the nuid inlet connection. 2. Use a hau briale brush with solvent to wash or

scrub off any accumulated paint on the spray gun.

3. Do not place the entire spny gun in solvent beau=: L It dirsolves the o h in the leather packhgs,

ausing them to dry out.

29

5. Lubrkatbn of cpny gun &odd be done d e (preferably before using). Oil parts (a) thmugh (d) with l i h t machine oil. CAUTION: Neva use lubricants containing silicone, 15 ailimae m n o t mtisfrtorily be flushed from cpny (un or ho ra once contaminated. L Fluid needle packing. b. Air nlve packing. e Side port control packing. d. m e r pivot points e. Cort the needle vdve " b l y spring with petroleum jelly.

C. All put sheets packed with spray equipment should be retained for future reference for the purpose of odering spare parts and performing rmintemee operatiom When corresponding with the equip ment manufacture In the event of difficultis, to aide in the solution of your problem p l u v indL a t e the following points whenever poarible. 1. Spray gun model number 2. Nozzle r t up. Air-Fluid- Needle- 3. -re feed- Siphon f+- 4. Bleeder- Non bleeder- 5. Air S o w * CFM- PSI - 6. Type paint used I . Type reducer used 8. Vismsity or reducing ratio 9. Type product being punted

10. Production ntc 11. Any other Information felt p a t i i n t , rucb u

prrrarre SettingE. XV. LIST OF COMMON TERMS USED WHEN

DESCRIBING SPRAY GUN PRINCIPLES SPRAY GUN: A precision mol desicned to spny rpply a mteri.1 using one of the thm brdc principles to atomize the material. AIR NOZZLE: (Air-Chp) The put of the spray gun which utilizes comprersed air to atomize and dimc the material to the work surface. FLUID NOZZLE: (Fluid Tip) That put of a spny gun which directs the fluid into the ah e", md du, rmes to porition the air nozzle. NEEDLE VALVE: That part of a spny p a wbicb regulates the material pasing through the nuid nozzle. TRIGGER: O p m t e s the ab vdve id fluid needle valve. FLUID CONTROL: Controls the volume of fluid by restricting the movement of the needle vdve. SIDE-PORT CONTROL: (FM Control) Controls ab flow to the h o m or wings to regulate pattern size and h p e . AIR VALVE: Turns the air on and off. FLUID PACKING NUT: Provides controlled pesp~re on the packing. preventing air from entering the fluid pasage or fluid from leaking out of spray gun dong

LUBRICATION POINTS OF A SPRAY GUN: . the needle.

a. Trigger pivot, b. Fluid needle packing.

e AlrnJVrpctinl. 6 Fluid needle sprlng, e. Sidcport control packing.

SIPHON SPRAYING: When mter id ls fed into a spny gun by atmospheric pressure due to a putial slcuum created by the design of the air and fluid nozzle. PRESSURE FEED: Term used to describe the procm of force feediw material to the spny gun using a pressure cup, tsnk or materLI pump, used for luge volume spraying or when the numid is too heavy to riphoe BLEEDER GUN: Fmvides uniform ih prmure at the ah mule of spny gun; air constantly flows through 41 nazzle of spmy g u e (Recommended when small portable ab mmprePors are to be used.) Has no air vdve unully.

spray gun only when trigger is actuated. EXTERNAL MIX AIR NOZZLE: Accomplisher a. tomization by mixing compressed air and fluid out. side tbe air nozzle by the action of air jets from holes which ue drilled Into the air nozzle. This method k normrlly used when fine finishes are required. SIPHON NOZZLE EXTERNAL MIX: Designed to cmie a vacuum in front of the fluid nozzle and draw rmteri.l from a cup by atmospheric prwure. This nozzle un u s l d y be identified by the fluid nozzle protruding beyond tbe air nozzle. Most Binks siphon nozzles of this type CUI be identKHd by the letter "S" in tbeh nomenclature. (Example: 66SF.) PRESSURE NOZZLE EXTERNAL MIX: Requires qrrzcure to feed the rmterbl to the fluid nozzle. May be i d e n t K i by the Iztm "P" in the nozzle d w tioe The fluid M Z ~ k flush with the air nozzle.

INTERNAL MIX AIR NOZZLE: Atomization k obuinedmd spray panern k formed by tbe mixing of compressed air and fluid ilcjde the air nozzle. These noaks usually a n be i d e n t i f i by a dot or round hole in the center of the air node . Up~dIy used to spray heavy mintemnee paints where a fine finish is not required. ADJUSTABLENEEDLE ASSEMBLY: One where the rhouldn of the needle is moveable to compenvte for wenr as in the Binks spny gum MUSHROOM NEEDLE, A needle with I flat tip instad of a tapred (point) one u d with fluid nozzles with luge openings, which are made to spn? henry mteri.lr FLUID CONNECTION: The point where fluid hose or ripbon cup connects to the spray gun. usually 318" &ugh1 pipe thread. AIR CONNECTION: The point where the air hose mnnects to the spny gun norrmlly at the bottom of tbe cpny gun handle. Urudly k 114" straight pipe thrud. AUTOMATIC SPRAY GUN: Used for automatic spraying applicatiorrr where the work k carried past the spray gun.

NON-BLEEDER SPRAY GUN: Air flows through

(Example: 66PE)

I

Fluid Nozzle Selection

made e r m m ~ .

practical lvlwkdge a d experknce with the nuny &ea of nui8 nozzles available and the tremendous variety of coating materiaIa.Howewr.forthe haa info“,me p r o p o r ~ k m u n M quite a myaiery.

The choice of a fluid nozzle b dictaled bythe amount of coating mdlarkl to be apmyad per minute, and the virc0aHy.Th. greater VM amount to be sprayed or the heavbr the viscosny, the larger me fluid nome orhic. must M.

Two primary mahodr of wntmlling the amount oi finbhhg malerial 10 be ~ p m W are by th. proper choice of th. nuld nome orihm and bythe preuure exrrt.d on me material bye preuure 1.nh or pump. Although most spray gun mnnuhctunrs have quRe I raw ol fluid orifice aizes. 0.022 to 0.500 In.. generally, this e r t i i deals with t h w common tothe spraying Of l a q u a n , O M ~ ~ i s and umihr coatings. As a guide m M+ accurate ulection of a nuldnord..me chart ahwid be helplul.The chart ir In “a n d i w according to

N O t t W m u c h t r o u b k i a r ~ ~ u n t e r e d f ~ v ~ m a o ~ ~ ~ l o ( O ( Each horizontal bar on the chart npnsents the range of nuid p~rruns that can M u608 lw each size of fluid nozzle for optimum apnying. The 18-psi maximum m u w e listed in uch bar wu ChOMn bcuutr. h moat -a, any higher prosrum brings poor atomkation at the eir nozzle. a6 the axil mlocny olthe finishing malerial leaving the nua n m e oMce b axmaaiw.

An eumpk of uring th. chart follows: H a 20-w~ 4 1 Ford matrri.1 ia lo M used an8 26 01 per m h llcy rata b deairee. 10lloWthe26-02lineuplntothemiddl~~iono~tnsctmrttor mint when il intenMtl wlth th. three ban tor me 0.046-In.. 0.052-In. end 0.059-ln. (luM -a. The 2&02 vertical line mms “ u g h a11 three banb best cho~m ofe nua nome lor them wndabnr would be th. 0.052-in. &e, M me ms- sum to give IM 2 6 a fiow rate ia abcul mamy between me pi minimum and maximum owraling nnge. Soiecting the 0.046-h. nozzle would be umirr. as the r e a u l d operating p n u u n wwM ba too hmh. chooring th. 0.059-in. n e e wwldalw ~ i n c w n c ~ u ~ n c a b w r y o p e r a t i n g p n u u n nwldMwIlar.

FLOW RATE IN OUNCES PER MINUTE

k b

,I i

"-

Air Nozzle Selection

AIR NOZZLES A spray gun nunuf.cturar'8 norria ch l r l l oHar nunmrous comblnatlona 01 air and Wid nozzles. Ju8118 in me wlac- tlon 01 a fluid nozzle, discuaaad in an earlier brua. ma uiedion 01 an air nozzle can also k confuaing. An air no?zle. Of courae. is that device which break8 UP the solid column 01 paint exiling from me fluid nozTle Into a finely alomizad and wall delined ahapad p. t tm. The dagrw 01 slomlution and dimanlion 01 lha p.tIWII are related 10 air noule I y w and lo impoaad air pmaura. For air atomizing spray guns them are two typrr of air nozzles usad. wllhvarialionrin bolhtypo~.Thase tw01yp.a are termed 'internal mix. and 'external mix' air nozzles. Tho external mix type la the moa1 commonly uaed: however, the inlernal mix is jual as important. Tho Charta indiuta mare each lype is appliubla. The menulec~urer's nozzle and needla charta should k your guide and will furniah Wch Intormallon as follows: e A series ot eir nozzlaa that will physiufly In ow a given wriea 01 fluid noaka. A manuladwar may have lhrw or lour physically dIHaran1 fluid noalaa and M.ralon special air nculas for U c h or( Wad.

auraor aiphon typeand OlanaxlarnaIorinteriuI miX1ypo.A prassura type air nozzla. olenharan exlam1 or 1nt.rrul mix type. isonathatrequireathe p ~ i n ~ t o k l e d ~ o m r w r a y g u n under praaaure provided by a preuurized vassal or e pump. A aiphon lypc nozzle. exlarnal m u only, k daaignad IO u u a e a vacuum lo be lormad on !ha fluid n m and merelore u u a e the paint to r i ~ up lromavesaalaltachad 10 the apray gun.

0 Tho Cham Wlll lndiula wtmther M. alr IWZZh h pres-

1. Annular rinp around the fluid nouie tip. 2. Containment holes. 3. Wings. horns or arm. 4. Side-port holes. 5. Anpular converpinp holes.

Siphon typo air nozzlas u n be used under fluid pressure wndllions bul prossun *pr air n o m unnot k made

e Siphon lype air noztlaa are uaed mostly where amall quantttiea of paint are used lor normal apraying only. Deco- rallve work auch as veiling. apatler and normal high production apraylng must be done wllh pressura type nozzles. 0 The charta will also serve aa 8 guide 10 what types 01 air no~Ie.8 aragenarillyuued~ilhmcvarioustypeaol coatinp materials. il should be noled that internal mix nozzles are recommended lor very alow drying paintr only 0 Some charla will provide a column lhal Indicates !he maximum width of fen pattern that u n be expected at some specific diatanca hom me work

fliully. me chart will normaliy have three columns devoted 10 air consumplion. Thaw are very importan1 as mey raiate IO me sha 01 the comprasaor rewired. Nozzle conaumflion of air ia usually reted d 30 psi, 50 psi. and 70 pai. ThB higher ma Dreaaura ma greater lha amounl of air. lhla .mount b 1.rm.d cubic In1 per minula (clrn). il a n be a6aum.d ma1 s compreuor will dallver k l w w n 3 and 5 ctm. Theralora. Il an air nozzle thn -8 ratad at 10 cfm and 70 psi were chosen, a ~ o o d compressor ot no iers lhan two horwpowar would k nMdOd. R u n be raid mal the higher me ctm rating of an air nozzle. me more volume 01 fluid per minula u n k atomized. In this win,~lollowslh.tIhalowcknno~lerun beowraledwilh small compraaaon by virtue 01 their having law orifice holaa. Those nozzlea with many orifices I r e high air uaera and must k u u d wllh large u ~ c t t y compreuors.

SIDE PORT

t0 dPhon.

.

NEEDLEVAWE 2 STEM INLET

3 3

.

AIR ATOMIZING NOZZLE 8 N E E D L E SELECTION

There are three basic components to consider when selectmg the proper nozzle and needle set-up lor y o u gun: ( 1 ) the air nozzle. (2) the nuid nozzle. and (3) the nuid needle valve assembly. AIR NOZZLES are 01 the following types: External Mix Nozzles may be siphon or pressure fed. They are the mosl commonly used and produce me finest finishes. Exlernal mix nozzles dim3 air into the Ruid after it has leh the gun to accomplish atomization.

External Mix

Air Nouls

External Mix-Siphon Fed ere Bed to siphon mateital trom a gun cup. Primarily used when small wlumas 01 low viscosity paint are required. Designated ty me loners 'SE" in the "TYPE" column d me foliowhg cham. Extenul Mix-P~rrun kd require pressure to supply me paint to Me gun. uwally a pmssure cup. pressure lank. or a pump. Used when large quantities d fluid am sprayed in production won. This nozzle type has a la rgeraw 01 selection lor fluid Row and does no( limit paint container size. Designated by the ldtleK 'PE" in the WPE: column of the lollnving cham.

Internal Mix

Needle Valves Fluid Nozzles

8ase

Internal Mix Nozzles must be pressure led either with pressure cup. Pressure tank, or pump. The spray pattern is determined by the nozzle shape and cannot be changed. These are recommended lor maintenance spraying where fine firujhes am not required. internal mix ryuzles cause the air and A u d (0 be mred inside the nozzle. therefore are no1 recommended tor fast dry malerials such as lacquers. Less lcg is reahed man with external mix nozzles. Designated by the lelters 'PI" m the "TYPE mlumn 01 the following d a m .

VeilinglDistressing

Needle Valve Spiral Fluid "Z!+

Au" core Special Efled Nozzles are generally 01 internal mix tyDe. They use vary closely regulated. low lluid and air pressures. These are usee lor such effects as: veiling, spatter, and distressing. They interchange with standard noxles on Bin& production guns. Reler to following charts. FLUID NOPLES perform these lunctions: (a) meter the fluid volume by the orifice size, (b) direct me fluid into the air stream. (e) form a sea1 lor the lluid needle lor shut olf and. (d) align tha air nozzle lor attachmenl to the gun. FLUID NEEDLE VALVE ASSEMBLIES are used to shut on fluid now and 10 meter the nuid to some degree Needle adjustment is provided on some guns to compensate for weer.

Nozzle and Needle Selection Air Nozzle H Reler to the 'Tvue of Fiui to be Srmved" columns lor . .

exemph of n&e types. ioiiowee by iecommenoed nozzle setups m me -nuid x Air Nozzles wiJmn

(2) Determine tha method of atomizalion. I e siphon or pressum Ibbdaxternal or internal mix

(3) Select air n o d e with an alr demand within the output limit 01 your compnrror. Remember to conrlder lhe air rwqulnmnt of omer equipment also rupplkd by the compnrror.

(4) Internal mix air nozzles are 01 nvo primary malerials '100 senes are 01 tungsten caroioe and 200 series a n 01 nnnlloy

Fluid Nozzle (1) Choose me fluid nozzld by determining the apDiarton

speed you want and the approximate flu0 VISCOSII~ The tancr Me speed or the heavlcr the I uid Ihe l a r y

none onhce sue snould be Reter lo page 19 for an orifice sue reterenm chan

the chan (2) Match the fluid nozzle to Ihc oesired air nozzle Der

(3) SeW the material 01 wnslruction: Standard lluid nozzles are hardened steel. Add "SS to nozzle number if stainless steel is desired or "VT if tungsten carbide is desired. Reler to Fluid Nozzle Reference

Fluld Nweie Vatve ( 1 ) Select the proper needle size number per the cham (2) I1 needle number is no1 shown in the than wtumn.

nozzle setup listed lhereto is not applicable lor that gun

34

Air Atomizing Nozzle Extensions

7 A

Nozzle Extensions designed to reach oul-of-*way places. Models for general use and for specific applications.

Ex(efn8l u 6.9,12,15.16,24 "na MIX 30.36.48.w.72.84

ERX

1 7~

2%

1 Y.

1%

3 4

38 -+a

30' sc

tarrml u 6.9,12,15.18.24 h"l Mu 30.36, 48. 80.72.84

Sld.ExtUWof 6.9.12.15.18.24 lnleml Mix 30. 36. 48. w. 72. 84

"1 of 6.9.12.15.18.24 Inumrl Mix 30.36.48. w.72.84

EnemI of 6.9.12.15.18.24 lnteml MIX 30.36.48.60.72, 84

Circular (360') 6.9.12.15.18.24 30.36.48. MI. 72.84

Cimlar (W) 9.12,15.18.21,27 33.39.51.63.75.87

I s!d. bloflul of 6.9.12.15.18.24 lnWnul MIX I 30.36.48. W72.84

High Volume Low Pressure - HVLP

HIGH VOLUME LOW PRESSURE SPRAYING Hw (high volume low pressure) spraying has quickly become the biggest trend in Anishing today. uses approximately the same volume of air p1 a conventional spray p.m. but at lower p r e y u r e ~ to atomize the fluid. Reducing air pressure at the noale reduces the velocity of the air stream and atomized fluid. This in tun has a positive effect by reducing the “bounce back’ of material from the surface being coated. The resulting spray is high in m f e r efetiency.

REASON FOR HVLP World-wide concern over air quality and hazardous emissions has generated an enormous interest in HVLP spray eqwpmenr Assuming a leading role in mandating more environmentally sound painting operations, the cplifomia South Coast Air Quality Management Disaict (SCAQMD) has spccised HvLpspray guns as one ofonlytwo types of spray equipment approved for w within im disuict (the Los Angeles bppin).

Similar legislation has been adopted, or is now under consideration. in many other i nduu iaked are= thmughout the United States. As these areas i n d u c e their own rules, the EPA will require them to be as rrrin. or stricter, as the California legislation. High -fer eficient equipment may ultimately be a requirement of operaring in the finishing industry.

Recognuing that the essential channerktic of HVLP is low air velocity created by low atomidng prrssum. the SCAQMD d e h e s HVLP as any device that atomizes paint with an operaring pressure at the air noale between 0.1 and 10 B I G .

Ovenpray IS a mqor problem for many compmes m the finuhing industry Vutuaily all spray fituslung opemom can be advenely affected by overspray and ttus can result m costly mamtenance and downume

operators of painting equipment are ais0 directly afrected by overspray. The fumes emitted into the air can be hazardous to their health. Visibility in the spraying area is also reduced by fumes and this contributes to mistakes and low productivity.

TRANSFER EFflClENCY A higher uansfer efeciency improves the quality of the work place by reducing unnecessary pollution and it improves the quality of products by providing an excellent finish.

Baseline Tnruter Eltlci.ny

w ...... -..- ..................... ...... w m s s ” i c .... - w. -m- .I-” ..-.-.. I A i r E h ” i 2 .--I__......- - Air-AuDwUrbs ........ ..-.. - HVLP spraying can be two to three times as efscient as conventional air spray which can cut material costs and waste.

Conventional air spray usually proves to be 30% to 40% eiecient This means that over two gallons of paint ye

w u t e d due to overspray. for every three gallons that ye

sprayed. With H” spraying at an efetiency rate of 6j% to Bw4 p1 Ilde as one pint of paint would be wasted for every gallon sprayed.

Another major problem for finishers u waste dsposal. By uaing m.HVLP system. with its high -fer emciency, wasti disposal costs are lowered.

Productivity will likely increase with an HVLP system became fewer passes are needed to build up the same Blm chicheu since more material is applied with each pa!w due to HvLp’s high transfer efedency.

HVLP vs. ELECTROSTATIC When comparing HVLP and electrostatic spraying you must consider the part that is to be sprayed. Unlike electrostatic. HVLP works equally as well with nonconductive pans like plastics and Woad as it d m with me@ substrates.

No special prrp.ndon or- ofthaaprrr b to MIR condnuio to mrmd m ea3llwrdn,

of the put is also a faaorrhen mMng chb eo" U the pan is @e a n U o r h t an Hvtp system M neet or exceed the rrpruler emaeneg of most clacmaudc spny systcmr On the olhcr hand Kthe pur hm a lot of CYUP &id shapes or open rp.ca. U e bicycle m a or chain Unk fences. electmwic syxtem wiU provide be= mans- fer emaency than an HVLP -em due to the 5mp' eUecr An HVLP system eliminua the pmblem of Fanday cage effm which a n p-t eleetmstPdc rysturu from pencaving into mared MIL

operatan tend to accept an HVLP ryncm mote readily than an 'c m m for severdl rew~nr. The main "on for iu quick acceptance is there is no high voltage 'stignu" associated with KvLp like there L somerimes connecccd to eleemrrun 'c handguns. Another major mason for high accepunce for an HVLP system is that it can be used with waterbawd coatinp without the need to Isolate marenal supply wk, or the circukh g system from the electncai muna HVLP uw onen berm dpke orienrarion control when applying metdlics.

The fact that an HVLP ~m h pacer adapubiliry and it is genenlly leu ucpendve than an e l e c t " ' system rlso makes it v u p popular with Enishing Opvnrlons on a tight budger

One advYluge of an elecmmrtic syncm ptprrxnf may lie in iu ability to hand& tugh solid rmfcripI?I and pmvide higher flow r&m to keep up mth dcmMdfag pmducrion SChcdulU

HVLP VS. AIRLESS AND AIR-ASSISTED AIRLESS Spray from high prusure. n o n - e l e " 'Cyn*ruchP1 airless or air-8sist.d airless, we gm.uy in ita owfu edicienrl from rppUcadon IO apptieadoa 'h performance of each apptierdon muR be documentad on a cmc by-case basis because many MI not meet the mmi" 65% udnsfer emaency requiremenu For thir won air-

w l l y accepted u complying with mini" murex eficiency sunduds u dnucd by gownmmnlwenaea On the other hm4 the 'soft spray' &om an HMp gun wil l provide a genenlly higher Udnsfer etliaency with a k n e r overall tinrrh. Recently. a study wu made of print droplet sizes. Three methods of atomization, working u peak ef8ciennes. were meamred for droplet sizes. Compressed air. including HVLP. produced droplets ranging in size from less than 1 micron to 150 microny. ~ - u s i m n l Ww produced droplets ranging in &e I" IWZtYl microns. Airless produced drupleu ranging in size from IO0403 microny. Needless IO say, the method of aromirvion chosen will g'eaUy effect the dnish For this reason airless spray untplly is not considered the Ultirna~ pmens for applying a high grade tlnirh mas and air-&ed airless aUow for an haeased working speed due to theu higher flow We. bur lack the Ene &rish cPprbilitiia of HvLp spraying.

I ~ S S a d =-- P i r l ~ system hpvc not ka univer-

The m f e r elllciency and llnish quality of M pirltss and air-assisted airless system m a y be improved by udliring a heated m a t e d supply system

u -- Whenit coma to selecting M HVLPswm that is bet for a parfieulpr job the facton tha! affect thir decision are the that should inauence the seleedon of any W h - ins-

Some ofthe most important components in rhir decision umking p m c a are the RVLP system' uomizPrion quality, mbabllity. the mpplien technical support and the avail- abiIity hxrvlce and spare par?s from the supplier. Among &me, a m e o n L.r probably the most c r u d element @the system Remember. Property selected air caps and h i d t&n are needed IO aswe proper atomization with an W g r m

W e m c y p e r of air so- are available aith WVLP -nu rhnt will provide a wide range of delivery volumes andprrmvaThexsoUnaBnbecenmlized,xrving multiple guns. or can be dedicated to sindngltgun w. Genenlly,maximum~rrmycisben,buttheairprmurr measured at the n o d e should be h r e d to 10 PSI, It's volume, ~t pres" rhat atomizes the coarink

RVLP sysuem hm a d e t y Of%Y¶ in which material h supplied to the gun Among these are siphon cups. pressure wks pumps and other " m t i o n a l fluid supply systems. now n!quiremenu are Usurll~ lower with HvLp than with air spray higher " f e r efEaCnCY. As a "UIt muller onfice fluid n ~ ~ ~ ~ e s a r e u n t p l l y c h m e n

TURBINE va. AIR RESfRlCfED HVLP'SYSTEMS The moa imponam decision h e n choosing an HYLP JYS- tan is be*seen the two U C air supply designs. One wes a mrbine generator tD m d e air flow and the other con- VCN GOPSIshop air 10 10 PSI air Uthe gun node . Both mnh& have their own advMuges and limirariorui.

for simiiar rppticatioru because of the

ADVANTAGES AND UMl lAT lONS OF TURBINE HVLP SYSTEMS When luing the turbine a V P W YOU get W a r pon- hdcy

an unlirmted supply Of COmPrrued w. m g shop UT

u not paprible when YOU'R Cotltlecrcd to shop pLT tines. NO^ d naushmg done III a s p n y booth wth

sources a h may not be able to oRer suBlaent v o h w for an Hvtp system.

U the UT make m e m and Its ater are well designed and mrunurned. turbine pu generaton pmvlde nkuvely dean. otl-he and dry UT.

Mcdon from a nubine wt can generate enough heat to p m d e m o d e m m temperdturm. but the t emper" of the au depends on the d e w of the nubine, its distance from the gun and the m h g value of the m conduL T~IS f r i m o d heat IS not always conaollable however. One must also consider the inconveruence of large and bulky ax hoses connccang the m i n e to the spray gun

7he nvo msJor drawbacks of most turbme synenw are that they offer uuufEclent pressure to a t o m some hgh m- mity or hgh solid matenals properly. Turbma EM also be m t e n a n c e prone.

Many tests conEm rhnc atomization of some matine from a turbine unit can be d e q u a r e with lerr than 10 PSI.

M e n you reduce the coating material with solvents m y of its expected qualities like coverage or hiding wiu be lost Doing so may also violate local air quality maictions. With turbines that generate less than 4 PSI of pressure Enish quality may be greatly affected.

The friction that results from the w of a turbiie CM atso be the source of serious maintenance problems. Many tur. bines are not designed for continuous sprayylg, therefore. the higher the t e m p e m gets. the higher the friction gets. and higher friction m e w shon bearing life. Because of the possibility for increased temperuurrs. mon turbines that are to be used inside a spray booth must be of a m t l y multi-stage explosion-proof design.

Remember, most turbine IWnUtacturen supply performance data independent of 'load" use. For example. a unit rated at 7 PSI may only deliver 3 PSI under load. Ask your vendor to d e m o n s m e Pressure at the gun n o d e of any system you are interested in.

ADVANTAGES AND UMITATIONS OF W AIR RESTRICTED AND AIR CONVERSION SYSTEMS A L ~ mad HVLP spnY gunt are desiped to m a aw pressure within the gun body. Ihe d t u a low p m s w &charge of UI unpmgurg into the dud sueam mulung III an " u e d spmy pycem wlth Im rurbulence and w m e AU " n e d models M the most popular HVLP guns in we. (See R p . 14).

&r convenlon wrs take hgh p~essure compressed w a n d mmct its flow so low PFessure u u delivered IO the spray gun. As with aar mtncted HVLP systems. the volume of au Irmrunmed.

The use of air restricted and air convenion uniu enable you to conml imporlant variables. such as hear and pres-

' sure, which aaect application p e r f o m e ~ .

Air resuicted and air conversion units can be outRtted with optional air heaters which pmvide the operator toul con- m1 over the air temperature. The heat can be varied or it can be turned off completely.

An HVLP system which uses exbthg shop air always d o m the user to add conmlled heated air which may improve tack or dssh m e . which reduces ~ l l s and sags. Uncontrolled heaced air may upsel the balanced chenusuy of the material and interfere with the proper leveling of the 6Jm

The p m ~ u r e of the air m atso be regulated with air maid and air convemion units. They can be adjusired to deliver pressures mging from several pounds to 10 PSI or more.

The inadequacies of air restricted and air conversion mts pnmyily revolve around its relationship with the air sup ply. Most H" spray Buns will require a 3 H.P. compressor or larger per gun to satisfy the CFM demand of the air nozzles. Edsting shop airlines and flexible hose must be capable of delivering a sufecient volume of clean. dry, oil-free air in order for the spray gun to work emciendy.

U the existing system is adequate for conventional air spray syscems. it will sufRce for an WLP system as well. It is ako recommended chat HVLP gum w a minimum of 5/16' ID. air hose.

38

OCMionrl nuintnunce pmcedura and ddiclorul esuip menrnuy be rrquued to UNR rhuthe sirir dan. dry and oil-free. If conrnminued air d o u dor thm@ the s p tem it could ruin the appLia(l0n. If the e m sir supply system is pmpedy mainmined for conventionrl air spray Mhing, however, these same procedures and equipment dl s d c e for an XVLP syrr~m.

Roblems WDClofed ' with either type of air supply method, turbine units or air rrrroined units are manageable. An educated buyer should be aware of potenrial pitinlL of any given approach and look for the solution that will offer the fewest o v M n Ilmitations.

HVLP IS EASY TO USE No specid haining is required to use an "em Operyors will m n lean the subtle difference between spnying with an HVLP synem and spraying with a m v e n - tiond air m e m XVLP, like mnvendond spraying, is available in siphon, @miry and presswe feed spaem* As with conventional air atomization, operatOK should learn to use the lowest p ~ w that is necessuy to produce a SaIiSfactOry spray ppncrn

hother difference is in openuor technique. 'Ihe gun should be held closer to the surface of the work piece when using HVLP equipment because of the slower forward weed of the atomized particles. Greater dimnee from the p M results in euyI.dyc dryspny and lackof tllm A good rulcof-thumb is to hold the gun 6'to 8 ' b m the PM that is to be sprayed

M y llrs~ time HVLP w m get the impression chu BVLP spraying b slower than convendond air spny. Genually, this b not the cpx. However, because the dlm thkhm with HVLP is often greater than air spray rynemr. fewer total passes are needed for the desired build Sometimes HVLP appticadon might be slower, but chis is g e n d y due to operaton who prefer a h e r dnish aver speed of npplicodor~ M e n who require fvrcr applicafioru HCZP compliance and higher -fer emdency m y want to examine HVLP air-assisted airless. See Binbs TD113 for funher deu i t .

Figuru 1-6 show typical air resuicted HVLP spray synuns.

In conclusion. HVLP spraying has become a viable proem in the Enishing industry, so. like any new approach, it can present many pitfalls for the unwary user. M o n of these IWS can be avoided with a thorough understanding of the process. The end result is a spray appticadon p m a s that will quickly pay for itself and lead to a better environment. due to the fact that HVLP system create less waste.

HVLP should not be considered as the cure for all Bnuhing problems. Remember. all methods of a m e o n will have their advantages and limitations. This include the process h o m as HVLP.

39

HVLP OPERATORS CHECKLIST 1. Is your compressed air MlDcc large enough? A typical

air Rspicted HVLP spny gun rquiru at lerrr a 3HP c o m p m r .

2. whrr is the lengfhand inside dipmctv o.) dthe air hose? It Is " m e n d e d that the shona length and largest LD. air hose that is pracricd for the job be used 5/16" LD. minimum air hwe is recammendcd

3. Are you using quick disconnects on yournirhau? II your air mppiy s)" Is borderhe, stpy away tram rhea Although these items are a convenience, they also ~~~unw~tedp-drop3whichmaymbbuable AiIp-

1. Have you seleetcd the pmper .ir and fluid d e ? Your csuipment SllpPliv should be able m give pmper rrcommendrdom. Remunberasyourllownta incrrw.youratomizacioncluali(ymrydeaeme. Experiment with a v a r i e ~ of n d e c o m b ~ o n i to 6nd the combindon that works kn

5. Checkyouratoznizationairp-alth.nairnde M gauge assembly. 'Ibis should tell you the pctrul .(omizadon air pnrnve being used as well p1 if you meet anyspeallc airpuPUry ngullnom (Ste F& ;3

AIR PRESSURE Atonunng pressurr must be set to pllow lor the dmp m au premtre between the regulator and the spray gun with 60 PSI applied at air supply:

Only41 PSI at gun inkt 25fsetof 1/4' I.D. hose cswesadrop of 16 PSI batween the au supply and the gun.

*aamx.bPSI h 54 PSI at gun inlet

25 feet of 5/16' I.D. hcse has a drop of only 5 PSI. For ths reason we mommend the use of 5/16' h e . (RECOMMENDED1

& NOT RECOMMENDED)

Cross section view showing companson of mlde nose diameters (actual me).

5/16'

40

OPERATOR TECHNIOUES The 8114 conridemion for a pruperly o p e d n g HVLP gun h operacar technique Mthoush no apecui ttduuques UT requtnd a m i e w of m e common faulty spny patterns and spray technique is u followa:

L 1. Air enlenng Me fluid supply could be

a. Loose fluid nozzle. or not seating properly due to dirt.

b. Loose or missing packing nut or dried fluid packing.

c. fluid connection loose.

caused by:

TYPICAL FAULpl AIR NOZZLE SPRAY PAITERNS Pattem Cause Correction

1. Dned pant in one of Me side port 1. Dissolve paint in side port hole with thinner; do not probe in any of the holes with a tool harder than brass.

holes of ar nozzle.

a. Tighten fluid nozzle. or clean fluid nozzle seat area.

b. Tighten packing nut, or replace missing or dried fluid packing.

c. TigMen all fluid supply connec-

3. Fluid pressure too low. 3. Increase fluid sup~ly.

1. Air pressure too low. 2. Excessive fluid velocity or loo much

1. Increase air pressure. 2. Use smaller fluid nozzle orifice, lower

fluid. fluid pressure.

I tions leading to spray gun. SPITTING

SPRAY TECHNIQUE The Bnt requirement for a good resultant f h h b the prop er handling of the gun. The gun should be held perpendicular to the surface being covered. and mmedpuallel with i t The m k e should be Raned before the uigger is pulled. and the trigger should be released before the make is ended. This grves ac-e m n w l of the gun and material.

The distance between gun and surface should be 6 to I? inches depending on mated and atomizing pressure. The material deposited should always be wen and weL k p each m k e over the preceding moke to obtain a uniform Bnrsh.

t 6bllhdm

c- %ti N - 9 W w

v -F-

GENERAL SPRAY INSTRUCTIONS To reduce overspray and ob- "um efUaency, d w a p spray mth lowest possible flulcvlv p ~ s u r e thu produces M . m p u b l e S P ~ Y paaem

Excanve vomrnng air PrruUra can Increase ovenpray, reduce " f e r eficiency, and w ~ t h some maten&. m u t t in poor &ush Wry f" dry spray. Atormnng ar pres- - should not exceed 10 PSL

For best d e ~3 U, 6 PSI 8tud pressure. Higher than 6 PSI fluid P- m e r u i s . Low Uiud P- W pmduce a narrower than normal spray paEtcm. Generally use 3035 PSI PV at gun lniet Unusually heavy, difecult to a t o m may rrqutre up to 50 PSI ~II at gun d e r

be reguued for heavy Wed

For bmn mfflsimnsy, 0l.c

spray and nbound should h l l towud uripaintmd sur- h e n (abovm). Alr movmmmt ovmr t h m p m d u n and uny. o1.r d t h m d - s p n y and nbound 8hould ba toward tha unpaintmd surlacm (right).

FINISHING

FINE TUNING YOUR HVLP SYSTEM

Some tips to achieve

optimum quality from an HVLP

spray system

t 4 Stan Puli Release End of

lngger moke nroke lnpper

I I - . I I

Coaling will be Coaling w~ll be

I / / I Ihghl a1 lh16 Pom heavy at fhiS pOm1 I

A good finish begins with proper handling of the aprey gun. Hold the gun perpondiculer to thb sutlsce being covered. end move it parallel with the sutlece. Holding chs gun 6 to 12 inchea from the surfeem, NR tho moke before the trigger la pulled. end nleese it before the stroke ia mnded.

BY JERRY P. HUND

A GENUINE concern over the environment is changing the spray finishing of wood producrs. High-volume, low-pressure a tomizat ion has emerged as t h e most widely accepted method of spray finishing in furniture plants. In fact , HVLP and electrosratics are the only accepted methods of spray finishing in Southem Califor- nia today - and possibly in your area tomorrow.

Most finishers who have switched to HVLP report they are pleased with its overall performance. Finish qual i ty generally meets or even exceeds expectations. As with any method of spray finishing. however. there can be problem. Some of the problems associated with HVLP a ren ' t t he result of equipment failure, but rather maappli- cation and operator error. With some fine tuning of your HVLP system. this gap between success and

failure could be reduced. HOW do you determine

if your HVLP system is properly fine tuned? First. examine the energy source or air supply. I f you're using a turbine. is it adequate in sire to handle the number of spray guns and does i t have enough pressure to atom. ire the coating!

Do your math I f you're using air-

restricted type HVLP guns, examine every component of the com- presxd an r up ply svsiem. Determine the air con. sumption of the spray gun in terms of air pressure (psi) as well as air volume (cfm.) These fipres are usually available from equipment supplier data sheers. Never expect the HVLP gun to periorm properly when its air requirements exceed the availability.

A typical H\'LP gun may q u i r e up to ZL! cfm

Becaw rhe average elec- mcally dnven compressor provider about 4 cfm per horsepower, simple anth-

-imetic tells you 3 5 h p compreso: is required.

A simple test to deter-

t0 perform FrOperl)'.

I

For b n t mtflcimncy. over spray and rebound should fall toward unpaintmd s u r tmcms Iebovel. Air movement ovmr t h m product and ury- over of the off-spray and nbound should be toward thm unpeintmd surtmcm (right).

mine if the HVLP gun has enough air is to slowly spray across a flat surface such as a cardboard box. If the spray pattem gradual ly decreases in size. the air vo lume is inadequate. If excessive orange peel is evident . the air pressure is too low.

Next , examine how the air gets to the s p a y gun. When using a flexible rubber hose. it5 highly recommended that i t be the shortest length and largest inside diameter practical for the job. For air-resmcted HVLP guns. the minimum inside diameter air hose should be 5/16 inch. Stay away from 1/4-inch diameter hose. k a w e air pressure drops as it flows through a how. it's wise to keep hose lengths that are just long enough for the job.

Stay away from quick. disconnect fittings if the air supply is minimal . These devices cause pressure drop and may lead to

frntsh problems. If ywr atr

er, they aren't a problem s u p ~ l ~ IS a d q t ~ , howev-

Watch your pressure Don't overlook t h e

pressure dmp through the spray gun inelf. Although some HVLP guns a re designed to cause a pres sure restriction within the gun body, for the gun to perform properly it's preferable to have an adequa te supply of air available as it enten the spray gun. Newer turbine HVLP spray guns a re ava i lab le tha t have almost n o pressure drop as air travels through the gun handle. As a result. the spray gunb air nozzle should perform at peak efficiency.

Air nozzle test gauges are a convenient way to accurately monitor actual nozzle prwurcs. They are also used to determine complmce with local air- quality codes by irpectors.

CHECK YOUR HVLP SYSTEM

I

1 what you wantI here are some areas to check. If the raulrs from YOUI HVLP spny system aren't quite

Make sure air supply is adeqrute for your needs

Are bath air and fluid pressure at proper Icvck? HVLP guns require up to 20 cfm.

Air preuure l a than 10 psi. fluid pressure between 3 and 6 psi.

inside diameter. and as shon as pouible.

properly selected and maintained.

Check the air hose. It should be at least 5/16.inch

Examine spray gun nodes to re+ if they've been

Review operator techniques.

Spray gun nozzles also should be examined to determine if they have been selected and maintained properly. Consult the equipment supplier's data sheers to determine proper fluid nocle orifice size and air nozzle selec. cion. Experiment with a variety of nozzle combi- na t ions to f ind w h i c h components work best for your panicukr coating.

Generally, expect finish quality to decrease as flow r a t a increase. Com- mon sense tells us t ha t with a given amount of energy avai lable . t h e more fluid available, the larger the droplet. T h e less fluid available. t he smaller the droplet. Thus. if higher mil thickness and f in i sh qua l i ty a re desired. spray two th in coa ts ins tead of o n e heavy coat.

One more tip The final considera-

tion for a properly tuned

HVLP gun is operator technique. Although no special techniques a re required. a review of some of the basics can always improve spray application eiiiciencl:

To reduce overspray, always spray wi th the lowest possible fluid and air prmure that produces an acceptable pattem.

L t c u ~ i v e atomiring air PrCSSUrCS can increase ovenpray. Atomiiing air pressures shouldn't ex- cetd 10 psi.

For bcst results we 3 to 6 psi fluid pressure.

Hold the gun perpcn- dicular t o the surface being covered and move i t parallel with the surface of the workpiece.

Stan the stroke before the trigger. is pulled: release the trigger before the stroke is ended. T h e gun should be 6 to

12 inches from the sur. fdce. Lap each stroke over the preceding rcroke for a

uniform fiiuh. *

Hose and Fittings

1. PRESSURE DROP A The most important mnsideration one must give

to the p r o m selection of hoses rad fitting8 k the premue dmp. The realization of what prexue drop k rad how It effects the equipment$ oper. ation must he understood. In order to understand p m r e dmp one must have a hasic knowledge of what C.F.M. (cubic feet per minute) and p.hL (pounds p e ~ s q w e inch) uu C.F.M. k defied as a given volume rir that nons past a given point in one minutes time, and P.LL is the m o u n t of force pushing the able foot of alr through the hose or t w L

6. Rcstridion through asx~chted it" Qch us. hone connections, adapters, nippleq valve& Ntm and air and fluid controls that are being umd in the system

6. The condition which effeck the p m 1 0 s in the selection of the h a e ue: t The h i d e dkmeter or oosseetional uea of

the hose hrr the pertest effect.(c.g.when a 117. inch ID. hose k used indead of a 114 inch 1.D. hose, the prermre ion in the half inch hose wlll he almost 20 times lea than the 114 inch hose for the aw conditions).

The m o u n t of ah that a tool comma will re, main conrtrnt for a given rt of conditions. The prrsrure rill always drop whenma the tool L W e d on rad, when the air begins to now through the hose. The prraurr drop will vary in relation to the djurtment nude on the tooL The n m e pressure loss o m when we rpert of moving a fluid through a hose. Therefore one must rlso mDlrder p" 1066 for the pmpersefedion of nuid hoaa md fittings

always be present. The only t h i i one can do k remgnize the uuaa then " i i the effects by considering the following: 1. Frictional redstance between the fluid arid the

walls of the hose. 2. Frictional lo5 as the fluid hu to flow ova

itself (internal resistsnn or shear). ThL k M u s e the nuid moves kan through the center of the hose m d slower against the walk.

3. The restriction of flow due to the change of dhc t ion the air or fluid must take.

4. The volume of air cr fluid the hose must euy in a given period of time. This h determined by the amount of hick p- in the +em.

5. The aehul weight of the rir or nuid h e i i au ied in the hose. For b e e , the elevation must be recounted for at the approximatexate of .5 p s i . per foot of Ut hred on water.

P" drop CMIlOt be elirninlted beclue it wffl

\ I \. I

2. Ar the length of the b e increws the p ~ n u r e dmp in- This dmp h pmportiond through out the total length of the hose.

3. The conditions of the surface of the inner tube will greatly innuence the p m drop; a rough tube CUI cause u much as L 50% haease In prarure drop.

.I 7 ,

II. HOSE CONSTRUCTION: A The basic wmtmction of most ah and fluid hoses

&e comprised of tbe following pa%: 1. TUBE.,

The only put In contact with the coating nutaid. It Is urefuuy selected to redst the mlvent action of the coating under application temperatures and pressure.

One or more L pz of high tendle fabric or mew braid bondled to the tube and jacket- quired to provide satisfactorily high working

and designed to provide d m u m

Tbe protective outer wvercbosen to resid damage from abrasion and wur , o h and cbem- iak and atmospheric exposure. .

A. When selecting an air hose consider the following points: t Tbe whme of air h t tbc bole must any;

tbis may be d e t e r m i d by t o W i the air conrumption CFM) of dl the ab tools

2 CARCASS.. .

rlz.tEty. 3. JACKET.. .

III.AIR HOSE CONSIOERATION

supplied by the 6 we at one time. See the m u -

H.P. Rmaui"

4106HP 6108 HP

11.12 12-1 3

6108HP

13.14 14-15 1516 le-18

2025

81012np i ex)

kctumr lltenture for amount& Thir factor determine6 the h i d e d h e t e r of the hose r a l u w NOTE Remember. the greater the volume (CFM) of air that must p a s through the hose in a given time the greater the presnv:. drrn will be. Below k a list of Y)he typical ail u ~ . ~ : l ~ - d equipment and theapproxlmtc C F,!,f. r y i + e d air at 100 p.ai AIr Motor bpiutor t v p l . . . . . . . . . . , ;:, C'h, &rlm Pump lone G.P.M.1 . . . .. . , . . , 6.10 CFM Airlm Pump Imo G.P.M.1 . . , . . . . . 20.50 CFM Airlm Pump l thm G.P.M.1 , . . . . . . , 3040 CFM Duttinppun Blow P n l . . . . . . . . . . . . 3 5 CFM Low promura Pump lJic+n l ~ i i l l i i . . . . 4.16 CFM Low prP1ura Pump lnudium mnrulcl . 10.22 CFM Low pewre Pump lhow mnnislrl. . . 2340 CFM R m u r a u n k bnvrizel. . . . , . . . . . . . . . 1 CFM sprsv gun Ihonmoyw w ~ d . . . . . . . . .2-6 CFM a r 8 V QUn (woduction @Xl." mix1 . . . 1015 CFM Soraiiun i k d u n m n t v p lmaMl mix1 . 5-10 CFM Spav gun I u n d a c M l q imerrul mml . . 1 bx) CFM

2 Tbe second factor In determining the inside diameter uired Is the toul length. This length c b o 3 be determined by measuring the distdnn between the ln ut point of the au and tbe point of ndt If pong distances are en. wunted, the reduction of the inside diameter in Wes will bel d u c e pressure Loa and Iowa the cost o! the bose over the entire length or by using a wipend. Tbe charts below indicate the pressurrs dmp in boss for tbe foUowIng condnionr:

AIR HOSE SELECTION GUIDE

brd on R . a u n Drop At 90 PSI Input

S/W' I.D. I lon 81.1311 -

I a Y

- 2.0 2.5 3.0 3.5 4.0 8.0 6.3 7.4 @.3 9.5 -

I

5.0 '.O P 6.0 7.0 I 8.0

"I

-

i 8 Y

-

3.0 3.5 4.0 6.0 6.0 7.1 8 2

10.0 -

+ 10.0 10.0

-

i 8 Y

c -

1.4 1.6 1 .8 2.0 2.6 3.2 4.0 4.8 6.0 8.2 10.6

- 1 9.0

5.1 6.6

10.1 -

-

NOTE: For dud production rpny gun appliutlons, 5/16 1.D. for a nuximumof50 ft. isthe recommended &e. For pump appllcatbns 318 I.D. should be used at a nuximum length 01 50 feet from the ah supply to the pump.

3. The third factor In rlecting an ab hose b the matems worklnn oresswe. The workine pressure

3. The total kngth of the fluld how from the point of dlcharge is another factor in deter. minlng the h i d e diameter required for the hose. To help In determining this, the following pressure lor chut is submitted for approxi. mating this demension

of the hose &&id be selected according to the blghew amount of prexure the system is caw blc of machlm? b-lo" Feet-4 -

4. The forth factor In the election is the materlal used in the construction of the hose. This should be b a d on the MtUm of m y llqUMS that may be introduced into the alr hose, either intentionally or IS a result of equipment wear, such 16 catalysts to CUR a plastic coating or oil leaknee from a comorewr.

rn Size of inside diameter required

"

5. The flexibility requirements should be determined by how many times the hose is bent or I.D. Of Ddir.ry in TYP ol Approrimmi moved m d who will be holding the hose. For no.. uud FI ozMinuti Fluid U d R-ri Drop a m p i e , men or women rpny opentorh

but on the benefits one wIU receive over the 1Y 1.0. 32 FI o z M I1 I Water 3 prl

E. Cost-Hose should not be based on initial cost 11, I,D, 32 FI OZIM (21 DOP 76 psi 32 FI ozlM 111 Water .5 mi 3/8 I,D.

e n t i life expectancy of the hOK. 318 I.D. 32 FI ozlM 121 DOP 16 mi D. Basic Types of Air Hose Construction:

1. Non-oil Ipsistant-a general purpose air hose recommended for spny guns, pumps and pre& sure pots, where oil is not present in the air supply.

2 OU reslstantmcommcnded for Industrial use and paint rpny applications where to cntmined oil and u t d oU mntamilytion b q u i d .

3. N Ion m t n c k hose pmnrnently coiled nylon -eMce where it is desirable to have the lir hose ntmct to an unobtrusive lou t ion

4. Ah how with a static (noundine wire Samers h e oil resistant hose exceot it incorooralcs a copper groundine wire 1; tbe bnid. Used mainly to prevent the poxibiiity of fire due to static d i r chqe m d puticululy belpful .in minimizing a finish failure commonly mfemd to IS mottiing.

V. FLUID HOSE A. When selecting fluid hoses I.D., consider the

following: 1. The uohmc gf material to be curied by the

hose in a riven period of time. This may be determined by checking the volume of nuid required by the tool being used.

2. The uiscosity of the material should be measured by instruments or compared to the way some Nbslances move. For example:

Ulsuid h i p t i o n cmtipar

AkOhol Very thin .2 m t e r Thin 1 .w K:sOS.?"c Medwm 10.00 Motor 0 1 1

X10 wmght SAE Medium Huvy 1w.w M o r Oil nnw I .m.w Cwn 011 VRy hUvy lo.m.w W l D S S C S Extra huvy 1w.m.w

I

b a t 71OF. 131 SA€ 33 Welahl Oil mr mururld 81 63 wands in a f 4 Ford

It must be remembered that if the hose has any bends in it or fittings, the p m u r e lonwill be grater. If the fluid viscosity is greater than water the pressure lox will also be greater. if the vkosity is l ex then DOP the prermre ion will be less. Therefom, since most l i h t consistency paintshaveviswsities that fall between water and DOP. a 318 1.D. hose is recommended to minimize the pressure 1% When the vixosity is grater then DOP larger I.D. hose should be selected. The approximate mount of material one can expect to find in wious sizes of hose lengths might be of some interest and are therefore listed below:

we Of nou L-h ol ((OM Comma in Gallons

1 N 1.0. 15 Fret 1 N 1.0. 25 Feel I H I.D. 1W Feet

3/8 I.D. 15 Feel 3/8 I.D. 25 Feet 318 I.D. 100 Feci

05 D6 2 5

.on

.14

.6

The amount of materiel necegvy to til! a hose is quite d l , therefore. when storing nuid hose it would be goad practice to keep the hose filed with a solient which will not attack the tube of the hose. Keeping the hose wet prevents matcrial from IiarJrning 111 r h c i l ls i- !c. brelking loow, and later plugging the nuid nozzle ,,r 11, Even though one may flush r)vt a how. a small amounl of residue can remain behind and cause problem-

B. Considartion of the fluid how mratruetion: mlvent nrirwlce chut howtng the suitability of nriour b o s a to mist different chemiulr and solvent& As an ride in decting the p r o p fluid bow for the vuiour rolvents, one might consult the foUowing chut.

1. Solwnt resirtoner. Not dl fluid b o s s ue able to rryd rU types of solvent and cheml& There fore. It is important to select the rIgt fluid hose for a c h application. Check the rmnutacturerr

I FLUID HOSE SERVICE AND SELECTION CHART

TYPES OF SOLVENTS, THINNERS,

AI kvdr IMinnrl Spwntl IN.pmk.1

EP0o.v Enen Coal Tart 1 PkP Urnhlnn IN~phlh , I Toluene Blind1

C k k . Rub. Zinc Rich Stliconn

I-

Poivatus PolyCStn Zinc Rich IMEIO IMIBIO

I'""""" Ene! Blend1

TYPES OF FLUID HOSE AND TUBING

ROOM TEMPERATURE SERVICE: CONTIN HEATED MATERIAL SERVICE: CONTIN

I 0OO.O 0A.C

0OO.O 0a.c

0 00,. 000

I I 1.1

IUS SERVN 'US SERVIC

Nvlon High Prwwi

A i r l a

- - 0.

0.

0.

0 .

0.

0 .

0 -

- 0 0 0

0. - 0.

0

0

0 0

- -

- -

0

- 0

iRVlCE 0 iRVlCE 0

Polvnhyler* Tubing

0

0

0

0

0

0

0

48

2. The wrking pressure of the fluid hose should be gmter tbur the highest porcmle pressure the system h apable of mcbing Hora ue n o d . ly rated according to the working p m r e and the bum parun. The type of QIC.~ and the numbex of braids required u c determined by tbe working pnrrure.

3. The tempvoture of the material and the am bknt (surrounding) conditions determines the materid the tube and jacket are made of. (No& anmy solvenu and fluids b e ” e more m t i v e when they are bated).

4. The flexibility requirements, 5. ”he weight of the bow.

C. Types of fluid hope available: 1. Fluid All; a nylon tube low p m fluid hose

with 1 rubber cover cabable of handling almost any type of fluid,

2 Standard thiokolfhid hose for mort type paints, 3. Compor hose for fine finishing matemk and

ha ted paints (NOTE: Not recommended for water bued pints)..

4. High pressure wire braided teflon hose for rll type of airless applications.

5. Nylon high pressure hose with a static pound. ing wire for mort standard type airless ippiia. tions,

6. Polyethylene catalyst hose (braided). is the only hose recommended to be used where atomired atab-st u e injected into tbe air stream.

7 . Eztruuon high pnsamre hoses bave an intenvl wire bnid wbkh is used witb heavy mrrtic type

0. Fhid tmmfer (high pnnure) hose dmllu to nylon aillar hose except it does not incorporate a static pounding wire,

9. Electrostatic hose (lowpruamre). a special com. position material, k used in its coastrubion m that it is able to conduct electricity,

10. Synflex nylon tubinp (low pressure). a hehly wlvent m b n t tubing witb a maximum a- mount of flexibility for nylon tubing,

11. Polyethylene tub@ (low pressure) designed to be used witb water type applications.

12. Retmct nylon horc ( lowpnsam). N O T E Gen- erally used IS an air bore but may be usedrsa fluid hose U desked.

mit-

V. CONNECTIONS

A.Hou connections and flttings u e available in vuiour thread styles and riza. The most common thread style used in the spray pinting industry are either N.P.S. (National Pipe Stnight) or N.P.T. (National Pipe Tawed). The N.P.S. style is the preferxed thread used on mort spny pns, rir and fluid inlets The N.P.T. t b m d style 6 the common type used for piping. Tbe most common size connections and fittings used &re 1/4”. 318”. 112”. 3/4”, and 1” in both the N.P.S. or N.P.T. style. In wme special Lnstonca 118” might also be used.

Sometimes cpehl types ue used such IS J.I.C. (joint industrial conneetbn) whicb are high pres. sure hydnuiic fittings. Ai r l s r flttings which .IC nomully over a 114” and ue used at high prearure ire J.I.C.

B B Not one type hose fitting will adapt to rll types of b o s s Therefore, selection of the proper type con- ngction necesury is dependent on the following: 1. The type of bore being used, 2. The size of the hose selected-ita inside dinmeter

3. Method of fpdening the connection to the hose. 4. The thread style and type, fltting size, male or

female type, required on the tool, rccersories such IS adaptors. nipples or valves etc.,

5. The working pressure of the connection. 6. The chemial and solvent resistance of the wet

B. Some of the typical type connections that are available ue: 1. Reuseable Connections are those connections

wbicb may be used over again when a hose has b e ” e unserviceable. They are available for ail production type air and fluid hour. Thir type of conneetion UXI a compression ring which wedges the hose into a ferrule, binding :he connection in the hose. This type connection is recommended for most conventional ipplics- tion.

and outside diameter.

parts of the connection.

. *Note: Without 1 comprrsion ring.

2. Ferrule connections ue used on low cost bore ueemblies. They ue not reunble.

D 3. Stmp connections for standud medium pressure

hose available in 1/2”, 3/4”, 1” 1.D. they aiso require a special tool for mounting.

4. Cbmp Scrra Type m o b l e conM6tiom. used where the hose hr an odd size outside diameter du, used for low cost inrt.llltionr.

5. Hose menders. a low pressure device designed to repair damaged h w by clamping the hose ends together JRW the damaged portion hu been removed.

VI.FITTiNGS Fittings are small miscellaneous items thU u e used In various wavs to intemonnect hoses. piping and equip ment to nuke up an air or fluid distribution system. A. NipplePDouble Male u e fittings with a male

thread on each end; these end threads ue not necessarily the same size or style. Some nipples m y Incorporate I wrench hex in the center poi- tion. They u e used to: I. Connect lengths of hose together, 2. Convert a female thread to I nule thmd. 3. To adapt one thread style to mother.

DOUBLE MALE NIPPLE

B. Adaptelshave one male t h m d and one female thread. not nerrvprily of the fame thread style or size. They are used for converting one mde thread size or type to another. Available in either standud or high pewre.

C. Swivel Adapter or Union k a connetion wNch has either two female ends or one male and one female. Designed with a swivel joint, which will permit one to break into a system or add a piece of equipment without having to twist the line.

D.Coupling or Reducer Coupling. This has two female ends which permits two pipes to be joined together, perhaps of the same size or different size.

E. Elbows, Street els or Swivel e lbowrA fitting de. signed for credting I bend in the line. Standard types have two female threads, not necerssrily the same size and are available in either a 4 5 O or 900 bend. Street cis are basically the 5 m e except one side has I male thread.

F. Tees and C r o s e d o r Interconnecting a third or fourth line into a piping system. .

U VII. VALVES

Vdva ue used in I system to turn air andfor nuid alpply on or off. A. The Upered plug v d v c u a e s matching tapers on a

plug and seat to provide a seal. rimilu to a gas 4. Note: They have a tendencs to freeze or ai& when used with fluids.

B. Ball Vdvcrr re the mort efficient means of con. trolling air and nuid. They us? a ball rotating in tenon sem to provide the following advantages: 1. A minimum restriction to the flow of air or

nuid 2. h e of actuation. T h y turn easily under full

load p w r e or no load prentre, 3. Wide nnge of intRchangeabie fittings for flex.

ibility of appliutioa Available in either stand. u d prreure or hqh pressure types,

4. They an be connected to indicate direction of flow.

50

C.Air adjustment or needle *--A mall- dc aigned to regulate a continuous Bow of air to i piece of operating equipment. Uses a needle or stan to rearrib the now.

Straight go-oeg.

D. Aircontroller-The Aircontroiler is a lightweight valve and pressure gauge Lpsem

bly for mounting at the air inlet to the spray gun. It oUers the time saving convenience of adjusting and controlling

atomizing air pressure right at

NU. QUlCI$ CHANGE CONNECTIONS: Quick change connections are designed to intercon- nect hoses or inmhange pieces of equipment rapidly and are availabk in either air or low pressure duid W. Considerations in .eketing these Items are: AForAir

1. Recommended when air line must be switched from one piece of equipment to another quickly.

2. They provide a swivel connection which helps keep h o u sudgh~

3. They can be used u a valve because air will flow only when the stem is mgnged.

4. Air now capacity of quick change dt- ungs must meet requirements of production spray guns which nominally are 20 CFM .nd 4 PSI pressure drop.

1. Recommended for paint supply syy5 terns where quick color changing is nee-.

2. Fluid flow capacity of quick change dtrings must meet requirements of p m duction spray guns which nomidiy is 32 n. oz./min. for a 20 centipoise material.

B For Fluid.

NOTE. Fluid connecuons, when coated or lined with paint, tend to malfunction when the paint drys. To prennt this, keep connections wet with solvent or .ohrent vapor.

51

IX. HOSE CLEANERS Hose cleaners are designed to flwh out fluid hoses preparatory to storage. wing a minimum of solvent in i minimum of time. The cleaner forces a minure of lotvent and air through the hose producing a scrubbing action that cuts away paint residue and kans interIor wpli of the hose clean. Advantages are longer hose life. reduced solvent usage. and de. u e w d cleaning Ume.

1 quarl capacity

X PRESSURE DROP mm mom mcu

L-2 U I C U

With valve d d . pressure is equal throughout.

nom m w am

mar 1.0 114 Inch

XI. NOTES OF CAUTION 1. Always know w h t kind of chemiulr, mlvents

or thinners the materials contain m that t h right type fluid h o u and connections m y be selected.

2. FmUi ize yourulf with the materials used in the construction of the hose that you ue deal. lng with

3. Never exceed the mommended working p m m e or temperature of any hose.

4. NWR use standard p- hose or flttlngs for high pressure ipplicattiom.

5. When working with high prerarre des hose. never bend the hose in LESS than a 4“ d i u , otherwke it will kink and m y burst.

6. Check 111 connections to make &in they ue tight before turning on the air or fluid supply system Eye protection should also be used s p c i d l y when using dangerous mat-

7. Always use proper tools when working with connections. such .I an open end wrench, box =“h ! k e or adj&ble wrench= Never use pliers, v k @p, or pipe wrenches.

8. Do not lose or overlook the comp&on ring or &ewe f” connectiom wbere this method k used to bold and sed the hou to the connection

9. Always match proper pipe thmd rita m d

10. Never open partiilly a valve or use it for regu. h t ion Always h o e It open or dopd 111 the way. Disreguding this wU ause the nlvr ylts or stem to wear out prematurely. or %ire d n W l ” .

XII. GLOSSARY OF COMMON TERMS FOR HOSE AND FITTINGS

AIR HOSE-A N h k r ho+c nude espcidly for sup plying air to a spny gun or other airqentd equip ment. Binks us6 the color red to desigmte air hosc and it comes in the following inside diameters: 1/4”,

indicate an air hose with a static grounding wire. CENTIPDISE-A unit of rlcority. conveniently and approximately defined as tbe viscosity of nata at mom temperature. The following table of approximate viscosities i t mom tempenture m y be useful for mugh complrison.

Liquid V i s i t y in Cmcipoita Water 1 Kerosene 10 Motor oil g10 weight SAE C.rror oil 1000 Corn oil 10.000 MoLees 100.000

5/16“, 3/8”, 1/2”. 3/4”, and 1 Inch. Brown ls uud to

100

CFMih-Cubic F e d Per Minute which k i measure m n t of a T O I U ~ of &dud air mewring 12” I 12” x 12” p i n g a given point In one minute.

used witha piastic lining when hot spny work ls to be done; never to bc used with a water based materid HIGH PRESSURE HOSE CONNECTIONS-Used on I nylon hqh presswe hosc for rules spnylng. INSIDE DIAMETER lI.D.)-The h i d e dimeter of the tube, hose linlng or fittings. J.I.C. CONNECTION ( h i m Industrial Commission Connactionl-Theseconnectlons ue g e n d y used by hydnulic or electronic industries and have been used in some rules application& OUTSIDE DIAMETER (O.D.)-The measurement a- mp. t h outside diameter of the jacket of the hose. p3.i. Pounds Pa Squin Inch Is a measure of energy or force ahow i vacuum.

RE-TRAK HOSE-A b o o that k Wound in a coll and rill spring back into a compact stre when released. This nylon hose k milahie in I/(” m d 318” LD. It may be u d for fluids too.

STAINLESS STEEL HIGH PRESSURE BRAIDED HOSE-Urd for d e s ipplicationr m d is more flexible t h n h i p- nylon and more solvent misun: WiU lLC0 withrrud more ahuse and has a I O D ~ R life thn the nylon bigh p- type. STRAIGHT PIPE THREADS-A drrdud t h m d system b a d on pipe &iza uod by BinLr for moa air and fluid connections on rpny equipment. Relier on

STANDARD AI R-Is denned as one cubic foot of air i t i atmospbaic of 14.7 p.6.i.. temperature of 680F. and a humidity of 36%. STANDARD FLUID HOSE-A Nbbcr hose made q e c i d l y for supplying mataid to a rpny gun. CM mu& be taken in choodng i fluid hose with the proper tube m that the mlvents used will not attack the inaa lining. B W supplies this hose in black and is arnitble in the m e si26 .I the air hose. STATIC GROUNDING WIRE-A wire built into a hose which k used to ground the spray gun Y) that there b ’ t an Clectricrl charge built up in the rpmy gun or opentor. SYNFLEX HOSE-A nylon hose, m.ky white in i p p m n c t . used to any fluid m d solvents which noraully lnect rubkr boric Advantages ye light weight, chemially I”, cleans asily, minimum p” l o q tnnducmt and low in cost. TAPERED PIPE THREADS-A standud thread sys tem found in -dud plumbirg system. Relies on interferena of t hmds to provide a d i n g slrkce. TWO BRAIDED CONSTRUCTION-Whereto bnids of reinforcement is woven uuund the tube giving the bore higher b W strength or working pressure nting. WIRE DRAW-A term used todescribe the p r m by which hydnulic erosion WPM iany i portion of a d v e o l t or dem

COMPAR (Hot bcqun Hod-A rpecLI nuid hose

’ matcbing Upud o l t s to provide a seal.

/ Compressed Air Supply

1. COMPRESSED AIR Canpressed air k atmospheric air which has been m e c h d l y

means of u " l . relared to perform a spedfic drrr of WrL. This atmosphere. the air we b d . m i s s of rpproximUely 78 percent nitmgcn and 21 p a n t oxygen. Aii has weight d this weight'is called atmospheric pressure. At sea level this pmm is 14.7 psi. This m w s hat the air pmm ucrted m evny quare inch of the eanh's surface at sea lcvel is 14.7 psi. This pressure is alm umed IO the sides and upwuds from the eanh: therefore when air is at the canpressor inlakc. h entm with the presm of 14.7 psi. A. AitRude The atmospheric pressure and density of air dccrcpsa as the a l d ~ d c in-. For example: around Denver, Colondo (6ooo h . ) t h e a t m o s p h c r i c p m L 11.7psi.Duetothcbwcrprrs- sure and laxr density of the air. 1 smaller (output) quanlhy of air is delivered by the canpressor. Air delivery of a e m p "

f O I d kt0 1 QCngC fhamkr Undn p a V e d then, With 1

i s reduced by appmxima&y 3 percent for &cry l@X~fcct in &muon a h sea i d .

B. Temperature There is an ad- ~ f f ~ on an air cmpmm'r prlormylce when lhe inlet air tempcramre rim above n o d . sludud air has k c n defined as being 689.. having an umosphaic pa- sure of 14.7 psi. and a 36 percent relative humidity. Stpndnrd au IS w d when tesls M ma& and effiacncia cmpuud; sun- d a d air is also the basis for rating compmmrr as to volume dcfiww cauabilida. Sbould thc tcmDmNIc r k sbon 689.. there 611 a 105s of air delivery e&alcnt to 2 "cent for ~ r y . l O 9 , i n b in air tempcram. Far aample: if a can- - pmsor IS operaung on a summer day, ar in a hated mrm aith an air t e m p t u n of 989.. thm would k a 6 prccnt drop in the volume of air d e l i v d frcnn its rated capability. Tkrcforc, haw the compmsor inaallcd in a cool WaiOD of thc plant ar mr a window, where good air drculation can be bad. C. Heal of Compression Air from the discharge side of a compressor is h a becaw it has been canpmwd. The temperatun of discharged air rdnga from 1509. to 500"F., depending upon the typ of cmpresm and the working pressure. The higher the working pmm. the p u r amount of heat is gcncnlcd. W h e n this heated air g w into the air rccciver wc m e t i m a gel I falx reading of thc air gauge. As the h a t is dissipated from the air receiver. the temperature drops and the pressure will dmp eYCn though no air is being uwd. This is becduw ha air requires more space and. conversely. cold air, having paler density. r e q u k less space. In order to have a -me" volume of air in lhe QOngC lank or air recckr. this temperature m w be brought to room cf rurrwnd- ing tempentun. This is done by means of an I f t e ~ d ~ ~ . With a -me*' volume of air in the receiver. ihe on-off running cyde

of the canpm is kept to a mini". When air is expanded. due to high temperatures. h e on-off running cycle will be imrascd. D. Cubic feet per mlnute (C.f.M.) and pounds per quare Inch (pd) Cmpmscd air is "red on the basis of wiume of air u . 4 (C.F.M.) E.I a given presuur (psi). The reference to volume of canprcrred air is alwdys a measurement of air in iu free aate; ar standard atmospheric condition. The following illustration sbwr a cubic Imc of free air, Mlparrd IO a cubic loa of air c0mpm.d IO 100 psi pressm

m

Note:

inncara, volume dmcaus.

. .

mde O f d OT Nbbsr C U U p i h . Thir UD prodUCC 8 lchivdy high lir wcplt la the mQoT S L r Tbc canplavd lif delimrd is vrullly oildhe, but na moisture-free. ud pres- nues M in tbc 30-35 psi nnge. Tbc diaphragms and AVM muire tqlaccmcnt horn time (0 time d e p e d i on use. Tbe

t i c 4 uid .ctrhetic in design. Wbcn sad. chc uni~ will run cmsatly, b“, hey be &signed for automatic moff opcmtion. Ewasive air p~tsslm is re l ied bough i built-in unboder nlve. Thic unit m a sun agninn bad-dl air must b e I c m a v c d f ” t h e c w p r c s v l r b e f o r c ~ . Diaphragm comprrrrorr vc designed for intermittent open- h, bm a t ud generally urcd ly the - mer. small plin* umuaclor, or bobbyin. B. Rotary Compnrron l h i s type hu become ~ a y POpuLrduring the p u t few years. ’Ibey LR usually quieter. easier IO insull. and lerc upearivc ~rcciprocating tps. This d a i i s bocedm the oprndng

bousii. During option. the nnes at held against the hou- ing by centrifugal force. A lubricating lluid is used in thac

sq~mttm in tbae canprrvon is my imporunt IO prevent excask wry mer of the lubricmt into air system. An absorbent type flier d m s v r p m from the unit would be te“dd. C. RoclprouUng Alr Compnrron This type is thc l m S t c I ” n ~ . Tbc pItsslm dum- beramriro of a pistm htled arih automain type pistm rings. a cylinda and intake and discbuge n lvc ucemblies. Com-

bouring die u l t hLl iQg 8 hri2ed emUrUCh. bUh h10C-

principle of 1 mor, filed with nnes ecccnrrically mMlnrcd in 1

tps la bah d i n g 4 cmling. RoprmsiDtenrnce of the

8 MAKi

air calm1 dcvica. .piIating opmtials. pneumuic .wp1cT arp ply systcms. t empram ud insrmmcnt cmud. 6n p” sprinkler systems. liquid or solid msfcr ly canpared air. uid cvcn rodent conml. Howcva. hem UR will IOM our men- h m mmprcyed air .ad iu usein tbe rpny plintbg imiusq. hm LI cbm LR “y w forsanpnsed air, mac Ucmrny tps Of”prr+uns. Each type of air Comprsa - a pu-

a t tps of comprrYors. their dnnuges lad limiulias. ticulrpurpo~e. Tbe b m ~ t l u r will dcsaibe n k ~ diffn-

A. DIaphngmTypa Alr Compmaaor4ll-Free This is 1 s d l hand Unied ~ f a s m p l l plint rpptU- bons. Air prcvurc is dcvelopcd through.& reciprocating or oscillating action of a flexible disc. Normally the disc is

parion can tskc pLce on either si& of the piston or m bah rides. W l m ccinprusicn rnlvs phx on both sides of k piston it is d l c d double ming. For genenl plrporcs the single a- ing type is most commmly w d . Single acting comprrssors CUI be cithcr single suge, or IWO sage or multi-stage. air or antacoded.

When air is dram tiun the atmosphere *ad cmprcstcd IO I given prcsrum in a single mok. k canprrrsor is a ‘single sage” unit. S i l e or multiple c y l i ” of cqwl bo= size may be employed. nKse units produce p” up to 100 psi, sam M.11 fractional H.F! units of this ryp habe 150 psi capability. Tbc efficiency of single stage uniu mr 100 psi is ycry poor. Operatan mr 100 psi is ucually nu recommended.

54

TWO STAGE COMPRESSOR

55

Ill. COMPRESSED AIR SUPPLY SYSTEM be canpressed air rupp~y system is designed to an dcquuc alpply of compraced liru aprdctcrmiDcdpaam m efficient opcntioa of .U air-opntcd alui~mmt. * Iyacm CpI ny in r i a fran a d. h.ad clnicd unit to we in-* ' . m &if ~uircmenu and cm- &j"sflJrtbac sywmue the yme:

1. A sangnrror. romecimarefemd to a s 1 bad orpunp, UD

2. 'Ibc p w u m e can be an el& rEuor, 0rpoSs:My 188s be mc cunpmsnr or i series of c a n p "

driven udit. The component units can be combined, or maraled iDdirrclly on a c o r n " hre, or mounted m up+- ne foundations. Drive connections most commonly em- pbvea ue.bcls and couplingr.

3. A c m m l or s t of conmls regulate the opnt ioa of the r m m l n d c l n l ~ . a. The control can be a constant speed unloidcr which

lllam the canpressor to opnte conlinuousfy, maintaining a pmet prrsr;un without awing the maM to stm rad stop. This system is genmlly utilized m pwuble when compressed air is emlinuourly r q u k d ty @uc- tian equipment.

b. The inlcrmittent type control is basically a pressure milch and is IrrcdmelcQriC S U t i o D P r y a m ~ The prrsune switch mpinuins a "CUI-in". bw prrrauc point. br example. 80 psi. WYCU the prrsave in the airrrccircr drops to this bar point. thc maor will stm and the am- pnrror will then pump up to i& "t-off high prr~nvc point which m y be 100 psi. thw brrrLing cmLcc and stopping the mator; when fbc prrrauc dmpr to its bar point. cbc cydc is rcplud.

c. Illere h c l u bc acombinuim of maefmbdr-cm- IUD1 spca unlodaand prrram $wiIdl. TaL combin, tim is = f e d to as dud cmrmlr. to be used when air deaudc nry.

4. Air intake fillen or silencers, or a combination of both silencer md hlm. are 'designed to mume intake noises as 4 as hlurout dun and din. The air fileris wy impofi.nt as dl air going in10 the c a n p r w u mun pus lhmugh mir film. The Nter element must bc mr& of fme msh or felt mrcerinl in ordcr lhll small pudcla of grit ud lbnsk msl d o n a pas into the cylindm. thus pmsnting d WCIT

m cylinder 4 s . pistm rings. and nhei 3. It is prcfenblc to haw i mcansforcodingthe dirchpgtd air

before it enten the air rcfeiw. The m01t imporunt can" medns is a unit knom as an Incrcoder. An lfiacooln an be made in many wyr. The most efficient is a arrursodcd unit which brings the discharged air temper" down to within a few degrees of the inlet ~ t e r ICInpenNR. An .ficrrooln is a necosvy pan of a good ~nprrssa syrum d is th primary requirement lor m o i s m "I.

6. ' b e air receiver must be properly sized. It c m m be ma rmrll or it will cause thc canprcnor to q d e to o h thus causing cxcevivc load on the motor. It should nu be too large because of spice problems and alm unnecessary apaciv. On a portable canprrrcor, cbe lir mim can be relatively small as it acts. primprily. u a pululing chamber

'Ibe Bumu of Standards, Washingtm D.C.. has st suII- d a d s designating the minimum size of air receiver to k raed bprcd on the air displacement rahg or the horwpwr for any given compressor. This has been accepted by the

ruher rhrn as a norage lank.

r a m p " r i " y r r a s t " i a n d i s * n n l l y I o l l a K d . volume of l i r for rhon

periods. alugc airrrcciveris frcqwnyld. Using luge aongc unka and mull ampresfom is f i l s , scmany. This ccmbinrtim wuld q u k the air c a m p r c ~ ~ r to opnu lor a longer pmod io maintain ldcquau volume. R c m d of this storrd air is nry npid md UD m l t in a temporuy shutdown of operations undl the compr~sor builds up the air rcfeim IO is full capldty. The only working air chat is mailable is what the comprcnor u11 produce rciording to iu r a d capnbiity

7. The in~mneaing piping. mU is. the piping beween the comp- lnd h e ~ receiver, can be copper Nbing or gdvanizcd iron pipe. If the unit is wncr-cwled. this will a p p l y m t h e p i p i n g u q i e g s t o t h e canprrssorand car-

8. 'Ibc disuibuticm system is the key link in the canprrsred air system. This is cbe hare or piping, or unngement of hose ud piping fran the & miVa to didbution poinu rcquir- ing mpressed air. This disuibutm system consists of the pmpcr shes of hose or pipe. finings. valva, air NUIS. oil and wter c~pIRors. regulators. gauges, lubricators md such other items that will provide for the effective and efficimt o p t i o n of rpcdrc air devices, tools. md spraying quipmnt. a. Thcpmprsia of piping 8s well 8s the " id it is cm-

structed of is impomt . Copper tubing would k the bat. thn galmaizcd or blpdr ima pip. If cbe canpm- KW quires oil lor lubricntim. the air hare must be oil mismt . The fdbwinB Chnn shw the coma p i p size

whp an q!e" rcquLa a

rying W " y to the dnin. or to the wm-cooling w r .

in

b. Thsc uebasiicooljdmhsand will have to k mod- ihcd to manmodate the piping fw a canprcsxd air syr-

run a " p r r r w i n Q buerqent or from a mck and the hare or pip my goouuidc and up IIUCC or four floors ad back in10 the building. If this wm the SiNauOn ad ic (v1s cold outside. lhen cadensah would bc a pmb km. ODC d d have freezing of the hose or pip . This is inadequate piping even chough it may be of the proper sia. h i s good pnaia if the plant is kng and narmw to instdl an exira air receiver at the far cod to act as a cushioa and help reduce prryurc drop when peak loads ue plnced m the compressed air supply. F'msure drops. IO a p a : extent. UD k m i & by encirding the plant- or boping the distributm system. This is accomplished by running the piping in a full cirde or loop hum the air rrccim around the pLni and back IO the air receiver. A double bop or cirdc is wcanpliskd by installing a tec in the lim and then running a bop orcirdc in bolh dmc- timr back to the air Y C C C ~ ~ . For this ryp of insllllaticm it is ncanmcnded that an am air I U C ~ ~ k inslllled at (he far end to baiana wt p k loads.

tcm in .ny prdcullr hution. At tima. 1 customcr m y

56

m w

c. whst typ of film, how many, or what reguluon rbould be installed in a compressed air system will depend entirely upon the intended end uy of the air pwr Oac inmlhticm may bc uring quipmcnt that requires oil lub ricltj, lor air t d s ; h e then an utanrtic line t u b M should be insullcd. In anuhu use. wherespying is dme. a lubricator wwld meate a problem. Rcguktion of air is vcry imporant. Less air is consumcd w k n urtd at low ptnaur: than at high prrraua. There- h. if1 t d can be opcratcd u 5Opsi ud plMt air is 80 psi or lW psi, 1 regulua should k instnlled to mud tbe air being supplied and i t iu k t opuscing p-. msquent ly using minimum volume of air and rfford-

necessary parts of compmred air supply system. No

possibility of contamination in air lines. Ai Blms or umam of the absorbent type arc tbe bat for this pur- p; hwvcr , drops or drop kgs can k &.

d. Ihe nuin discharge pipc (hcak) Wing the air ncciva should k slopcd away fmn the comprrsx thrwghan the entire distance it runs, with a dn ins f f 11 all low poinu. The take off from the main header in the lir supply system should be f" the top of the hcdcr. La- sull 1 tee in the main M e r facing upwards wih two elbows returning back d w n t m r d the E m . This will keep condensed moisture from entering the mol being ured. 'Ihis d a s ma. houcva. prcvcnt moirmn t h i s cu mdenwd fmn entering the mol or the line.

ing Iwropcntingconr Airline film or urnaorauc

nvncrhow wcll the unit is W l e d tbm is alwyr tbe

THE PROPER METHOD OF REMOVING AIR FROM THE MAIN HEADER

IV. CO"wwm IN SELECTING AN AIR COMPRESSOR

A Appllcatlon

caxwmpbic f o r d tad. ud whalmui"pr ryurcr tbill

bc g h r n pmvir i forthe fuan d d i t i m o f l i r ~

Fm. d y tbe apphlim. Fud out whu type and how many air consuming d c v i i .IC cumntly b c i i uscd. what the air

b c m p i d for any mc &ice. 0n.x wc know bmw mvch air is & UDdn m n t openling wnditiaaC. rmuidmcion g u l d

devices This anticipated requirement should be added to the " ~ 1 rystem requirement. In dditim. a safety f w of 1 last U percent must k allowed to compensate lor b w c d efficiency. luh. unforeseen contingencies. 'life t w l of the .boK will give ur the required capacity to be rocanwndcd. Qlaru uc Milable S h m i n g the air c " p h ud ptnaur: nting for various trpes of air opuucd quipmcnt. his wry imponnnt that h e canprrssoryou relea is the wnui type and size foryourraxls. Scludor chpnr No. 1 and No. 2 tvill hclp you mpLc the p p r choice.

6. Pmasun whm is me h i g k t prasurr required for anyrirdevice? This will de& whcha or na )vu will quire 1 single sage or two stage c m .

C. Typa of Unll DeIaminc what c m or UmprcssoIS uc to be rcfan- mended. One should always rmuider the poyibility of using nvo comprcson. ax b e or full UpaCiIy unit brtbe d. full-rhin vmking dly and 1 rrmllaunit fortbe vford rbift or

quid. Tberr uc llromrnycascs W k me rarl air quire- " 1 is supplied lrj la4 "-; chis,cln LIsllc 1 constant s0lu.a of airsupply in the uce of flilm or l"m '

d me unik In operalion5 W b air suppry is critical. 1 Mm-

PoprfUDaioning ud WOrLing Nlilabiity.

panid working day operation where full u p d t y is no( re-

O f a K

mm pnccice is to provide i sundby unit and normally, this d b y uuit is opnted almnmly m a weekly basis to insure

The combination to be selected is Io k determined by an mluiticm of the needs id economic factors involved with tbc prqu n i g h t given to cuh.

0. Controls In &torelea ud pmvidc the p" typ of ccntrol q u i p

h tok made as to the openting cydc " I . 1 dctmrunnwn of tbe comprryor. This &"hation will be mpdc by uamin- ing the UWI 10 the lohving questions ud then relating the mode of a m p " cpmtim b a t suited to the inended use. 1. Will the air usage requirement be intermittent? Here. an

utatutic run-stop control would be b a t ud set u) that the opcming cyde ntio is Ipprorirmcely 113 running time and 213 dum timc.

2. Will tbe air w g c requirement be fairly constant? Here. I amsuit service c o n d wuld k bat.

. .

3. Is me air w g e pallern 1 cool- of me lbove, intennit- mt during YIlM pnodrud conslat u ahar, rothat PJ hm an imgukr requiremenu s in"? 'Iben. in such an inruna the ba t u w ~ e r i s tohm I dlul c0n~0I--bah the iuvxlutic sun-stop ud constant m i c e inrutlath. This permits the w r to obtain the best economic h u g e in canprrya op€" in this drcumsuaa.

Ibc pmardecdm rbould k dctcrmiasd by am of p h t b mode of openth d mticipced fucurr mob

0 nrb opndao. Mury rima (IY lypofccmrml will be selected for the immediate need with pmviricus lnade forthe d d i I h 0 f the dtcrmtc mafml.

MN JN some rddltlonrl SuggOStIms: 1. LiadI0ftheliropvrleddevica)auexpnto~fmmthe

2. TaJrheseflulirCaWm*figurrr

compressor with the average free air consumption. (Use aun No. I for clplcities)

3. Nae the highest p+ssurr q u i d to opntc my rml. 4. Fa inlermjmnt vrvise refa to chn No. 2. cdumn A. Fa n" ~ v h a c Lodr LIC in CQISUDIISC. uucdwna E.

b. Within this range, hate total camnpfim of tmlr c. F o h line OCIOL( to the ~~cmmended B i Cwprrs-

a. Deccrminc prrzwc m g e nu&d fa opcmtioo.

$01 Model Numkr.

A v e n i e *k Coar~mntion of AirPorered D d c n

c 16. 7 . 2 7 2.2 7.29. 1.8 7.8-1 1.9.

4.24.9.. 1.8

E. Voium al& lircanprrva dMcd for the Mlrl dum (cfm) dc- livered. n a for canpurcd ccanpnrcor displfcmcnt. A d e of thumb for figuring rcnul cfm delivery u 100 psi L:

EleCPiEMaor = 4 c f m p e r b o n e p w r Cis Engine = 2 cfm per honcpower

F. Elrwtlon AI what ~ I M I ~ ~ Y is the comprrssor to opntc? A canprayrc bra 3 pment in efficiency for every loo0 fcet of elcntica.

What will the (ambient) surrounding temperature k? The higher the ambient tempentun the more m o i s m the & can contain and therefore. the Ius air the camp- will pump. Wamsooled units might be required.

I~M el& maor is &. what d u g e and phue ue q u i d or available? Nae: lor k d p w r cost. mmm of 2 h.p. ud L r g a should utilize higher voluga and thrrc-phru current. 1. Loullon Will the elcctric mmor m the compressor k in i huvdwr

G. TOmpWJtUN

n. VOkJgO

haQa?A rpci.l crrpbipm0f"risquirCd wbcDHa dust or g u mly be prrvnl in the Lwirmmcnul umorpherr.

V. ACCESSORY EQUIPMENT A. Controlr-El.strlul 1. Pmsure Switch: coauols starting and stopping motor i t

ret ptuwe. W d to maor lads k w e n manual s m r ud motor. or '2-way pila" device in magnetic s u e r . Wbcn air pressure reaches cut-out pin t . the contacts in tbc pressure d t c h open and stop the motor. Cmml can k adjusted for vuious prruurrr drpmdhg upon requirements. NOIC: never change the pressure switch without

2. Ignition Stop Switch: Grounds out ignition cumnt at ret prcssun. stopping g u engine. Engine must be resuned when required pressure is to be supplied. Conucts work oppaitc to thc of p" switch.

3. h h d SUna: Uruplly hu sun-~top b u m in UNCI with arrsabunm vadcrthe ccrverlrud when the maor has kea rbutdavll bcuuw of an omlord. uudprimvily for mO(0r

protenion. conuins thcrmil overload relays which will open. stopping motor when overloaded or low voltage occurs. Power line goes dmctly thmugh mmud SURU. ducugh p" d u b to h e maor.

4. hrgpetic Suns: A more diable mclnr for mota place- Coo hr a pwh-bum pad to mad m-off opemtim. Lo

the p" switch u a rrwo-pde pilam .crintc a mapoetic coil whish, wbcn energid. c a w cbe c m w to meet. f d h g pwrdLsl to the maor. Thir isthebcst mbodof mdor paCnim. espec*lly for m o m larger Ihan 2 h.p.

5. Fused Disconnect Switch: This is i knife-type. off-on switch. coouining the proper sized furc. This should be

the hued dircmnut 10 the s u k . Fuses should k hrge eaougb to hudle 2% dmcr thc m t ndng stamped on the "r. A qualified dcarich should ah^ mk cbe elec- uiul bookup of m air mnprssm.

cmrulting the "ufraum.

mL, mc p o m g a r uvarph runcrdirca to the ma. using

prcd It a DCII the c m ~ u n i c wiul the liac going han

B. ConholcMsnwl I . Lodlar SWMg Mcchmiul. Tbir is, in c M . i mcuu of

Leeping tbc comprsm from working until the m o r EM revh its full OpndnD sped. ky lrccpmgthe suning load of the mdor u its minimum. a. Swim UIJovling Val=: Most air cmprrssors ISC this

mum to recmoyc che bad fmm the cmnpresor. It merely bolds tbc s u c h (a inuke) whe diu off its scat when audng the mnp- so that when air is b u m into the cylirder a m rbe inuke srmk it is exhausted through the open inuke nlvc preventing buildup of prruurr in the cylindcr ud, cmsquently, h e maor d m n a wrk during chis phru.

b. Diaphragm or Piston Unloader: This is the p i n which opens and closes the suction nlves. It consists of i diiphngm or piston (that comes in contra with can- paced &) ud a linkrgc ora pin capins. which operatc m cbe nlve disc causing it toopen. The lir to opentc the diaphragm or piston unloidcr is controlled by I pilot nlvc (>wry de) WM in ~WII is controlled by prrya speed. oil prrzwc. or ail p==ue.

3. Ikrl cmaofr. This u a comb- O f W me - mat ~peea unl~rder (for cmtiouwr opruiao). tbc durl armml cmr*o of rh ekmcatt rapuind for- sun- * pl- & pikc wrbdn. a ShUIoff nhr rad UI airopr- & nlvc. The rhut-afl nlw is inrullcd 0 che air ida ride of rh pikt. nK pila is sa to opauc .( 1 praaur m l e u c IO psi k b w r h ~ ~ u h mrinp. -the nln is dosed, che compressor will opente thmugb the

$witch mud (iitcrmimt); with che rbaofldw qm. me Canprryord operuc W U B h Ibe pihc lmkakr (cminwuc). ne UIQ glinsbeaefur fmm IhL. becloopr- .IC the unit m conrunt speed when the d e d lor air is @ut. rad can switch toinramimtrcrvicc WheDdCmudis small or to merely maintain pressure lor small jobs. Tbc rmrll dditirml COM of durl cmrrdr is 1 vcry arofiharhile imamcat for my customer who may have a tluccuaIing dnnrrdforiwmpascdair.

4. Uand Unloadcr. Uand unloading is simply taking the bmd f " a ump- by manually keeping the in& or nu- tim valve off its KPI. The unloading is accanplished by muns of a auction unloading nlve and a scrcw-rypc or kva-rypc linkage thnt is opened by h a d to force che inukc ntve open. This mcaac is ucedprimrrily w h r r a c a n p l a s n i s akded a d y ocusk4lally and is avmd m ud off by a mrinuMnct man: typical insullations k ing Fm RacnioD md Wucr supply Svrrrmz

5. G u Engine Idling Wit. This is M air-opmted dcviEc mu. w k n iarullcd a l a gas mgiDe driven ccmprrsoz will C.UIC rh engine u) idk when mCsanpasl*mdmio Y(

pressure. As cbe c o m m unloads. the air bolding the diaphragm d w n is also applied to& i d l acmud m tk engine Tbe i d l a control. in nm. pushrs %aim the cu-

dmps due t o p " b c i i d d -the idkrs"J. the comprrsror R Y L ~ to pump -mg tbe s p e d of the

mstvnirm (h indmt opntion) ad tk

LNJlemrCcild m. sbwiIlg IhccrlgiDe. WbcnchepKsuTC

~ ' I h i r d e v i c e i s ~ ~ f o r u s e a r i l b t h e ~ 2 Cv--

c. satsty Acceuo*s 1. A safety nlvc is furnished with ocb c u n p " unit .od is

ret to blow before the pmsurr rub rh nccd working pasurc of the air rrcciva. nK yruy dw is to be lotcd paiodrally to mak sure it is&. Not.: If it is DQ 0pCnf.k. or the oprntim is sluggish, SWmQI smsc dic- utcs that the valve be replaced. Compressed air can be dangerous and its pmvcr should be given due A uur who attempts to opnte a comprrrcor with the safety nlvc

maol device 00 the unit can apa to encounter suioui ~ u c n c c s .

2. Bclt Guud: Thisis 8 safety devLt Ihat islegally q u i d i n m01t sum. A comprrssor unit is to be insulled in rmrd with &e manufacturer's recommendation that the pulleys face a wall. hereby dimking any possibility of &nu

D. Ylscsihneous Accessorbr 1. Flexible hose connection betwen air rrccim rad piping

. . DQoperalinp. ldefeaive airrcfcim, or any "trig

ryrcem. 2. W t d i m & . 3. In& m1Pr uld SiIcnCerr 4. Handler and holding brackets for hoisting portable air

somprryon.

~ . s e n u c b r i n b r ~ c o " . 6. W w r ~ f n w u e r z m l c d ~ d .fm-

Wden

VI. PREVENTIVE MAINTENANCE A. 011 Changes. Fdlow faaw nm" ' inchmg- ing oil. Most manufaaurcrs require an oil change every 9X hours; sooner if cbe oil tccumn dirty. Use a nmdcmgcnt, oil (dimatid) or rpccul oil devebped k r air wm- persorr. Oil will cktmiomu due tochpngiag tempknue and muminatim fmm lbsorbed dirt. Note: Saw smnll porublc uniu do NoTRquirr oil. B. Inlet Flllsm. huc rad dirt arering rhrwgh the inuke can

m becanedogged rad CllldmLe the in& c r d q UI exEcI- siw ylfuum. thus curring 'Oil pumping:

cause rmsiderpblc dunage to h. riup rad cylindm. Fd-

C. Bslt Adjultment. New 'V" belts will saetch slightly lftcr about one week of operation. Tbcy sbould be adjusted at that time. Belts should tlex about 112". If they are too tight. and excessive load is placed on both motor and compressor main bearings. If they are too Loose. they will slip causing them to wear excessively; a h . the compmsor may run slown real- in inefficient pdn"c. D. Working Parts. Tbc old rd.ge--'m ounce of prevention is wonh a pound of cure", C a n be literally interpreted 8s it applies to maintenance of a compressor system. A periodic inspzion of valves. rings, kpringr, contml mechanism and a h r puu s u b j a to wear rad their replacement wbere such is needed, can pment costly breakdown which may occur during critical productim priodr E. Dlatrlbutlon Syatom. Small air l u k s are costly and tmnccarary. A pcriodii soaping of dl connections a d the ccmaing oficakl will gunnlct &dcnt ~ n n l n c c from the WmPleJra F. Clean Air. Thc use of .flcrcmlen md proper typc aten acxuauon is auntid in hwing a dean rad dry air system. 0. Dnlnlng Air Recelnr. Tbir may be h by opning the dninnhr (daily) al me unk ainnrlling 8n lutanatic dnin. H. Rating Tho Air Recelvw. Rriodic testing of the air r e s e i v e r i s I c 4 ~ by mrny Nte rad bell coda. Asreceivm begin to age. mci l b i t y to opruc uadcr high prusure loa& begins Io dexrase tbmInc. hydmsufjc mling to validate the air rrcciver'l A.S.M.E. kbel is q u i d .

WI. TROUBLE SHOOTING A Low Air PNsrun. Tbc custaner says he d o a n a have enough air or rh.1 his pmavc is na high enough to o p n ~ his equipment poprly. Thc uuse can be amibutcd to one of the folbwing: 1. Insufficient &pacity. Gcnenlly one will 6nd Ihat the re-

quirements for air exceed the supply-the compressor docs no1 have sufficient capacity-primarily due to the subsequent addiam of air dcvioa. Here ihe lolutiOr, is to provide an additional compressor or replace the present

larufficient capacity can bs due to a dfunaioning inukc valve. A very simple check can be mide to determine

b e air filter from che inukc on unit ud hold chc palm of )wrhnd ova& in& hole. U whud is dnwn to the hole ud held tight by maim tben p u my assume the cw-

unilwithODC&ViilLrgercrpuity.

wbcthcr or lkx the unit is FcdCmbg properly. Fmt, RmOYC

, , ..

p r r p r x i s o p e n d 4 s ~ ~ . ff.bomrpurhndis

p h i l l g facc m me pdmofpmw. lhm me* in na held cight but Nheris buffed bocfr o r p a fd 1

me unit ire n a sating proprrfy d tbe&tbrt is being drwp into Q comprrswis b c i bbvDbn2 wtthmueb me dischrrge. if it is n u btiq crmpsscd t b ~ @ thedie

nlvc into Q air r&civa. A slight lclk in.= in* *spLreducC meeffidmcy. 'Tbc r c d y bere istobm me unit "i.

2. Inadquite Piping. The inside di.wtcr of tbc p i p is (00 d t o ~ t b c K q u i r e d d v d u m i n I g i v m p r i o d o f ~ 'Ihirsmk rbc main l ine ,b~&. ain many ara. QE- miaed flow is c a d by the rubberhaK utendjng to Ibc md. By rcfming to lir capacity Iables orchlm kr wious size base rad p i p . OM uo determine wkrhaorwC I* uuna hu the proper size of p i p C a m p 4 air should be delivmd to i tool with I minimum of p- drop. The d y ties in eitherinacrci Q size of the p i p 01 hm.

in the uu whm difficulty is he iq encouowd. Anaher remedy would k to 'bop" the disuihution system. lhacby m i d q drastic prruurc dropr. In this typc of distribution system. the additioo of a lir m i v a w i l l insure I

h t h c minimum p i p size touy 8s imnin be should m- ak l a than the sizc of the canprrundirchnrge opening. hctors to carrider M hou, the air is king 4. the numkr

intermimntJy. U the shop is large rad the main line Ius I canidaablc dirtnaa to mu, t sewad air nceivn ianrlled u the far end of tbe run would hclp s t D b i prryurr. h is Icrmetiwr more CCmOmiul to dd ID airrraiwthul to hm Dcu piping installed.

h g s , thc awming ud Eoolingof heswill d t in bt- age U vuiols linings ud .xmMkas. 0 t h c r C " b u ~ to lir !us uc WmI out quick duage dirmDea couplerr. l ak -

dnia lines). d i m p p a use of air (annc).

with a brush to each pit wiu indiucc *rha or Do( mu

couplers will pmrc to be the mort eMnanical sdutim. Air

orifthic is i m m , toprwidc 111 UlditiaJlI comprrrvn

bem smrrd of linc prrrsllrr. It is g e d y rrcanmclujcd

of dtopoffs. md wherha the air is being wd cc"fly or

3. Airkkap. A vay canwa of air bar is 6nd in t lw disaibutioo system w h m . duc (0 6cuoIuI UmpaDm

ing nlver m air dcvica. open nlvcr (u on drop legs or

Leakage in the distribution system can k chccked by tbc c o m " method of %aping''. A soapy ~olution applied

joint is tight. Rognmmed maintcnlnce of air devices to rtplacc worn scats. cw.. rad to rtphcc faulty discollnur

is nu k. A small. continuow leak, say a hole .bout 1116'

vcntive maintenance is less upnsive. 4. Misuse. By misuse we mean waste. A worker will use his

dusting gun IO d m off his dotha or cool himself in the sumMlTiM or to dust the floorinsrpd of nveeping it with 1 b". Anaherca~lar ~ o u m of mte is on thc dnin line OT drop leg whcrc the d v r Ius been *cracked" to permit constant draining of condensed water. 7he remedies for these arc obvious: Improved supervisory conlrol of em-

provision of an rutomatic dump n lvc IO control the dis-

9. Contwnlmtlon. Amha common diffidty caearnlcrrd

dim= UD cmt Ihe l ~ f ~ 515.00 IO 530.00 p r m t h . Re-

pbycs, r c d of surplus airirdcvica when nu in uy ud

charge of mdenvd tntcr.

in Oanprrvcd SysUmS CCQMMhI Of air k. s h

Q ryacm iroomplndy d c d ud drcmnlr i n e c dkaica. n n y b tbecomprsroZ hkallyrruoolblc IO- thu

campesrnin* oris me rrrull of smefhhg t huh t prrced lhrough I h e c n " i n i n u k e . This ismemlyvay airlines in

cause3 mu"? Tbe fdbuing uc rypiul:

my forcia rmttcr in the air iystem b u puscd lhrough &e

i comprersed air system can become coauminmd. What

I . Moisturr Moiin~e uuy( pipes to mt ud. Lptcru it dries. scales uc formed W h i c h bKak bac ud M urried in the airmclm-to

m l t i n g i n clcersivc WC.I or malfuncticaing. To rcmm moistwe, lir must be coded below its dew point. prefcrably be& it is discharged into an lir rrccivcr. Air d e n can- prcssedir ha, rad it is nccusary to wol this air, to force cmdcusatim s o ~ t o ~ p p ~ resulting Mtabeforcitentm the canpressed air system. l l ~ ~ lir rseivcr .N as 111 initial -for was, radoil. butthis is nuits funaion;it is M air nmge rank. The moisture cmmt of tbe auwrphm nris with tempr- mnc. Whatever the moistwe m t e n t of air is wbm it cntm the compressor inukc. the air temperature king funher nircdbytbe~ofwmpmsionrrsuluinimoisnvcm- tent m b t i o n to a higha ydpor state enahling it to k curied io the air meam without difficulty. As lhis moiscu- r i d air tmcls lhrough the system. the t e m p r a m will dmp uod it rcyha ram u m p m OT i u dnv pint, then the moisture in lhis air GQdcnrer ud is the "e of wur in tbc system. Thc pmpr method of cmaolling this uadi- tioa is to rrce I waumled IhcMola. By "ing cod wp- ter through the rftcrcwlcr. rtducing the air umperaturc bum .bwl4oodegrra to lbout 70dcpm. tppmrimucly 90 p r a n t of tbc moiaarrr d be IcIL)(Ned rad cadenrcd into water. Sinee WKCX is buvi cbm air, it aill seck the low.Stpoin1 radhrc U this point. i m p is insulled. If. mp is n a 4 , wwer wil l colla in the baurm of the air rrcciva. IfM .freMolermubc lncd ud ifthedimibution lioa uc!tmg enough todlw me l i r to cool before a i used.

pmvisions to dat the w.3 It the ln" of the dcvict.

Anulm oyy ofm- is the prrrcaoc of oil in the

c h s t i s ~ w i p c d n n y fmnlhc cylindawbythepism ringr udis urricd into me air s" LT Oil npor-the high

bdge in 1 VdW S W OT @Ug 111 d e 1 IO M & &a-

~ICU i tlla i t the far cod of the air spurn would k the next bar thing. l l i s film should h m an rbrorbcnt dement .nd

2. oil

ryaun. Grmally, lir mnpi- w i l l hnr I aruin m u o l of oil vaporprrscnt in the discharge air. This is the surplus oil

tempmnvc in the cylindcruiuing the of oil. As the oil "par cadchccs. it canbina with the mim thnt is plcsmtto lorm amilk-like liquid. One dropof oil uo m a n M of appmxinutdy 9 square feet of I pan of wucr-id- athe c m m when a pisum type canprssor\rurrbout ax 4uu( of oil forerery 4,000.oa)CUbK fcuof air it pumps. This oil when used in 1 rprny gun will mix with CoDting mu-

will with the rir nw. oil ~ l l l be ~movedonly with PD rbrorbmt type fkr. Passii rir thrwgh UI .bsorknl hlur will r c m m the oil; when h e filter dement bccoms satu- Ned. it must be rrplafcd.

d s d caw f i s h fail- Oil is much morc difficult to r e m m than water since oil

An lftcrcoda will mp 1 d .mount of mc oil SeepiW imotbc rynrmin iu nonlul O p n I i a I . utbc -is bkily Wml and l n acariK lmountof oil is rwDdinIk air lyncm. me prill ccasI8nlIy k dunging Blurr Thir unit is

t o o v a h u l t h c ~ . c0"Cnly d C d M 'd-punPr" ld thc P m p a d Y is

3. Din QD bc very crrily rcmorsd with i proper 6lta m tbc

wmprrvor inkt port. M M y fitcn arc nailable. the most common k i n g the screen ryp. This ryp has nu pmKd nryeffectivc kuuce it is M* king wed pmpaly. fi is sup

arcb the dinpm*les astheypystJuough. H a m u few will maintain this 6lrnin chis and. therrfo~. it is seldom used. Ibe majority of ierullacioos will pmvide m oil bifh type of filter i t the intake port; the air passes h g h the oil oronrthc oil. tberrbyremoving the dusIor din pracnt in the inwdng air. ?hir is LD effecrive means

mailable, the felt ryp is wd in many insrallstimr Local cadi- will dLure thc typc most suirable fa chc pmicu- kr inrullatios.

"bcdippdinoi l togivethcrreear'~"t0

brdin ud dust Kmoupl. Among ahercypcS Of din @IUS

VIII. GENERAL NOTES 1. Alwnys fill a new air comprasan ifrrquired. with nudvd

iufomariVe omdetergent oil having the proper W E weight or the special oil which has been formulated for air c a p prcyorr. (See low oil prryurr item la, Page 12.)

2. Keep air ccinplcyorrc far iwy u possible hun the painting M.

3. air infs.h fitels dean u 9 times. If tbc row cmuips i havy cmccnmtion of dust OT has i high humidity, pLec thc air intake outside. If limg pipe ~ l l s uc midabk. i

one pipe size for each eight foa length or tun. h i d e i large enough Nter ud a wcllha shield for M outside intaLr

4. If the comprtsor is not q u i p p d with i loadleu suning mechanism, do not stan the ccinprc+ror against i,bad- 6rsh remove 111 air from the system.

5 . Form el& moor drivcn camp-, the voltage, a m p age and proper phasc ~ l ~ n t must be known ud milable to operate the elecuic mmor. The follovring my be of ym k i p io detemrining the proper kngth of extenrim ond for rrmll pomble el& comprcssorr: 314 b.p.. l l S volts. single phue q u i m 10 amps while operating ud a No. 14 cord lor SO h. 1 h.p.. 115vo l~ . s ing lcphax~uircs15unprwvhi l co~ uing ud a No. 12 cord lor SO h. 1.5 b.p.. 1 IS volw. single phase q u i m 20 amps while operating and i No. 10 cord for 50 fi. Note: Suning cumnt draw can be thrrt tima u high rc

the operating current. and fuse pmcctian should k i minimum of two md one-half times the operating currcnt, whenwr possible. A rule of thumb for calculating the ippmximrtc cumnt consumption of i n clenric motor for a& boryxnvcr of energy dcliwrrd: 1.h.p.. 110 volts. single phase q u h 12.8 amps. 1 h.p.. 220 vdw. single p b q u h 6.4 unps. 1 h.p., 220 vdu. thrrt phase q u i r e s 3.2 amps. 1 h.p.. 440 vdu. three p h w q u i r e s 1.6 amps.

d e of thumb is to inncrse the size of tbc pip in the Nn

Alnyr operate i mmor U the highesI volugc possible. Man lqa thrn 1.5 h.p. rbovld pefcnbly k operated

will be higher tor single phzce mdor acecdrng 1.5 h.p.

Ijnc phnc u spccif~ed m the mdor l u w p l t e . 6. W b c n ~ u an extension cord is rrquirrd. use me having

the proper sire wire in relacioo to its length IO ~ssm it willcclrrythekd.

the canprruort electrical load. R C m any aher elcc-

mchreeplluc u cbe inidarn, aswellu openting a t .

kwrcnm cbc maor is UMmCd lothe pmpr*duge and

1. Alwryr fuse 1 comprrvort el& iupply. 8. Be crmia rhu the dcctrk supply is upable of handling

triul equipment that m y k on the same circuit. 9. Running M air c w p m r o r i t i p- higher than i u rued capability will l o m the air volume output, cause a d d i t i d %tar, and rhorim the life of the quipmen:.

10. Chcck "load heater elements in magnetic motor SUR- crs. Hater elements i re ilwdys stamped with ampere ratings. These should read Ippmximtdy 5 to 15 prcent higher than the full load rating of motor a1 operating voltage. This full load rating is sumped on the motor nameplate ad is also indicated in amperes. Too high a cuing of heater elements giver no praedon. Too low a rating c a w stanex 10 Chmarout during surting periods or in ha -Iller.

11. The air rrccivcr should k LD A.S.M.E. cmihed wsscl. This means rhu it carria i label cmiryi rhu it is con- m u d in accord with the A.S.M.E. (A" Society of Mcduniul Enginem) mde lorunfued prasurc wsscls. Most nrrccodarqui~~ periDdic bydroswjc cstingto see thu tbc tlnlu continue to c" to code rquinmcnts Altemtimr nudt to thc air receiver in .ny manner will indidate the A.S.M.E. cmifiuu aid m y violate loul cods .od lffea me plantr io5llnnce c w m g c .

12. chc~k di" of rotacioo. Mok air comprcrpon indicate

rult tbe manufacturer's compmror inslallrtion manual. dirrcdm Of r0Ufh byM -a &he)' Whccl OTCon-

N O k somUnitsrmyopaucin my direnim. 12r.laar oil prrravc UII k caused by OM of UX following:

13.

14.

15.

16.

(a,) No oil. @.)Wrong direction of mtition of the compressor

Ry-VM. . . k.)- oil pump. Discharge piping must k adequately sized and installed w)

u to sbpe away or Mnrd the comph+m. Drains should be pmVided u low poinu in cbc system. C . u h is IO k exercised in using pmablc (hand carried) corn- They haw i undcncy to 'wplk" or crap. when in operahn and care should k ukcn in their place- men:. In 111 insunas. it is rcfanmerded thnt the unit k recurdy anchored. especially if placed in overhead locations LW a r k damage is porsible if the unit should crccp. buIl a sewer dmin in h e heon of icomprasor 100m for the r e m d of cordenred water from the air receiver or lfummia. Rcrd all iamuaionr pcruining to the air ccunpraror and cbe related equipment kfon openring UX unit. Additianal lnfonmptian can be obtlincd hun the quipment manufacturers. For information on the installation and trouble shooting of Bink's air cmprators. see Pan Sheet 1767.

62

IX. THERMAL CONDITIONING AND PURIFICATION EOUIPMENT A. 0.n” *removal of m0-u fmmarmprevpd airh imprmnc in the inlclcst of dery and pmccnion agliart dunrge to lit rods. “ials. rrd pmauac. ll is impatsnt Ihu Callprsai air be d c d . dried. and d d b e h it is disaibuud for we 1. m e n lir is compressed it becomes very ha, ud in chis

uulitim. it is a paentid expbsi . Danger of a Callbus- tion explosion. in either the air receiver or pipe liner, is always present if the air is not sufficiently cooled after laving the comprrssor. Heated air will result in less air k ing s t d in the nceiv- cr. hold more water and cause the pipe lines to expand with subsequent conmion when the compressor i t shut down and the pipes cool. This cooling will cause condensation and the dtcrnate lengthening of tbe lines ulti- marncly produca leaky pis.

2. The air in the atmosphere is ncvcr rully dry. Water in a vaporized condition is dwayi p m n t . the mount b e h d e n s a t i o n occurs is in d k a proportion to the tempen-

ocher words, the haur the air. the more moisMc it M hold

it can hold. A change in either praurc or tempenlure up sets the equilibrium of water vapor hlled air. If the air pssure i n c m c r and the temperature remains consunt. air bws i s ability to hold water and cadensation ulra pLcr This is the procus which awes nin. orwaur rcumutrtiaa in air roceiven. pipes, rrd wur a- Corn+ air koms s d a as it lpprorha the cnd of the b e In cooling. it baa i s capability forwrying mois- rum in vapor form lad thereby tbc moism it cmdenstd md discharged in liquid form (water). Sudden expamica of compressed air at the point of dischuge c a w rapid.- (iring). The water vapor in the air is thcn funher cmdcnsd nnd carried through the air dcvicc and discharged inq Ihe armospherc. or in many insma dischqed mto the wrk or process k i n g p!”cd. In pneunuticdly openled machhes. lhis Idcase of w.1cT re- m o m lubricating oil mlt ing in equipment irvfficicncy and deuriwption. It may cause excarive 115u m nlm, faulty opention of air contmlled quipment, rust. -km, finish failure and if thm is a possibility of lim: f“g, the Y-

cumulation of wter in b w points in the distribution system may wlr in bursted pips.

3. Vapori2cd oil can present operating and maintenance prob. Icms. Too high a temperature and excessive oil npor in 1 critical mixture with air can mu11 in a combustism upk lion. Adherence to safety prncedurrs nnd proper mainre- m c c of control quipment is panmount. Oil should be removed beforc it enten the distribudan system; cna then it will creep through and most likely cmlnminnte the prcduct or pmcas. Oil is inuoduced into the air supply because of compressor w a r or i a high operating temperature. Note: ’IXs problem is ncf present in the oil-lss typ corny.

4. If rdid plnjdcs or aher impurities, such as rust. dust. d- wnt vapors, overspray, etc. are present in che immediate a m p h m . t h e may be drnwn thmugh the canpressor ip takes and find their way into the air distribution

nuc of the air and inwscly pmp” lo the presswe In

in vapor form the greater the presure. the I C 0 anrcrwpor

QSan. ’Ibc kl&tb atering a “praxnvill ”h-

rreueeffianry, daaiome litdnirarrd in UIQ Iucb as Gnihing. dfa the quality ofthe bairb. ff MI is pamc in tk disdurged air, it Mutes thu the pips or r e a h LII: mud. nbt rc” in the sysum a unit has been in- d c d ul8t is Cmmuaed of incomcc “ill.

.o mersarivruurrnd pcm” puu rrplromau. dc-

8. Aflercoolan The primary consideration is to nduce the tcmperaNre of c o m p d air. Hut. as well as m e impurities. u11 be a- & by ins~alling an lftafmler in the system. Aftercoders arc very efficient in bwering air temperature and removing mt of the oil ud wmw. the residue of oil and waur slill be rcmowd before it enters the air receiver. There arc several different designs or typa of aftercoolen mailable. The most common is the water-cooled “air tube” design in which air pasts bough s d l Nba rrd rc-eireularing water is dirracd back and fonh moss the rubes by 0fbPwc-s and moves in a direction counter to the flow of lit. This cross-flw principle is acccpled Y the most efficient means of k~ apnsfer. The air is cooled to within IS’ of the incoming city water temperature. using approximately 1 ‘h gallons of water Tor each 100 cubit feet nf compressed air passing through the unit. For example. on a 5 h.p. unit with I9 cubic feet capacity. a cooler would w I H gdlms of water for each 5 minutes that the compressor was actually pumping. The water flow is controlled by a solenoid operated water controlled valve which operates only when the canprrtror is “ing. If the comprersor is opcnting with 8 consIan1 specd unbader. then an air operated water control should be installed. Oil nnd wmter leave the lhmoolcr in a liquid state. king condensed by c&#. Ir is either dLened to flow back into the air miver or tn a moisture ud oil rcp.ntor which can be l U t c a U t i u l l y or rmalully dnincd. ’Ibe afurcmln is an ascntid ppn o r a CDmpletc and pmpr ly functioaing ccinprrswd air supply system. The larger the air compra~or and the higher the operating prcyurr. the greater the need for an Iftmmla. 1. Cmsihtion in vkaing afummlm arc:

a. lhc m i m u m volume of air the lftncmln must hmdle. b. 7bc m i m u m working prcyun of the aftercoder. c. The required temperature drop for the compressed air

d. The milability of an incoming cold water supply and

e. The sire of the pipe connections at the aftercooler for

f. The mans for removing cadensd oil pnd waur from

WPplY.

its tempenlure.

thc inlet and outlet of bah air and water supply.

.the system.

f WATER OUT

. WARM AIR IN

- f WATERIN

Water-cooled aftercooler

63

C. Automatic Dump Trap

will d lea cordcnvd moisture. I! is 10 designed thuk mp opcns automatically IO discbarge a predetermined volume. Due to the air pnrauc kbind the pntcr. the mp opens and doses with a snapaction that insures proper rU&g Of the dosing valve. A s d line mrina should k insulled lhud of any automatic device to keep loreign particles from dog- ging tbe working purr. If this unit is properly .iasulled. with a line smincr. it dl giw long and satisfactory service wivith minimum rmintenancc.

D. Air Dryen Good Iftcrcoolm wil l r e m m the greatest percenmgc of pn-

tcr vapor but the midue can nil1 caw problems. For example, if 10 cubic fon of free air holds I a. of water pr cubic foot and this volume is compressed into 1 cubic foot. at a higher pressure and temperature the moisture that YN in the IO cubic feet wil l k ccntlined in Q I cubic loa d u m in the form of w e r vapor IS long as the temperature remains cleated. When the air cools down to i u original incoming temperature (into the compressor), a11 the water vapor will condense except for that amount lhnt was in the original cubic loa volume of free air. This will condense out vrmnrherc in your distribution system or k carried inIo your air tools or finished product. There are many designs of air drym milable: among there the most common are chemical. desiccant and refri&ntion types. All dryers arc designed 10 r e m m mOiSNrC from the compressed air supply 10 that no condensation will ulre pl.cc in the distribution system d e r m a l ororking eoaditions.

Chemical drymopemem he principle chntaminchem- h i s d l ma with moisnuc. forming a dut im tvhicb will

This mp, iorulled u Q bwspoint bclw Iheailrraive.

1. chemical Dryar (deliquesanc. dcbydnIor typ)

dnin Io rhe baum of chc dryer and krrmowd. The &m-

as used in the o p e ” have Io k replaced IS they M consumed in the process. The chemical can be salt or a specially lormulaled material. a soluble chemical desiccant which is more efficient than salt and is non-comive and Don-toxic. Most u r dryers “scrub” the air h e times: Fmt, by the mechanical separator; second, by the misting system; and third, by the soluble chemical desiccant. The plh that air b l w bough a chemical dryu is Y follows: a. Mechanically-the entering air st rum parwr through II

d e wbich atanircc the mOiSNrC drippings from the desiccant chamber. The air strum is then merscd in direction. causing condensation (free water) to be thrown dear. collecting in the bonom of the unit for autormtic OI rrrmlul discharge. Daicuat min prc-dria the air. h p l e u from the der- iccant bed are a mild chemical solution, created by moisture vapors slowly dissolving the desiccant beads. AtomiUtion of tbe dropleu by the entcring air strrun creates a bg-lik m i x ~ r e , a c h panicle uill retaining an affinity lor moisture. This rrsulu in about 60% of mc pntcrnporbeiig RmOved prior Io the air ”’r contact with the desiccant bed. minimizing the usage of , the nw daiccant buds. .

AIR SUPPLY LINE

NORMAL INSTALLATION WITH AFTERCOOLER

U Desiccant dryer

3. Rcfrigmaim Air Dryen Amtfhaovnl ' refrigeration system soolr Ihe h a t exchanger by chilling the air to i temperature klmw the minimum tempen- hu is utainablc in tbe disaibutim system. As hmg u the temperature in the system remains above the

dcnuticm & na &. dryaqlqmuwe. the Smditiarr fortbe b l m a h of a-

1 AIR - 9 OUT ";'," -f=

Refrigerated dryer

4. Ddiqucrcnl Dryen The deliquescent type dryer removes moisture from the ~omprrrredairthro~gh mcm~.l-. 'ibe a i r n w uuuugh a cmlaincr of memiul pll*s u sbwn Q FW 8. As Ibe moisture (liquid ud npor) in the lil cmuN meJe pcllcu it comb- with (be @let dmming i rolutim in the boaom of -the auiner. This rduticm mwt be dnimd rany m a periodic basii Also. siaa the water divdva the chemical it must be replaced periodically. Deliquescent dryers cm hudle my Lrge airvdumes but M uw.lly lerr ~ & U d r y i i a i r ~ a b m ~ ofdrym

Deliquescent dryer

5. tiDcFJmaOildWatcrExuufors A line 6Iur is to be insulled at any point in the dirm- butiw Boa where air must be dry and oil-fm. This is “ d a t o r y if a comprrrred air system is used wifhout M rhnsodu. The best typ line iilter is the absorbent type where air plsa through an element of YIW marerial that will absorb water rad oil panida. Remember t h t water always seeks a lmv point. wh- oil putides uc urried vith tbe air. Some oil and water extractors are combination filtcr- regulators Ud UT convenient where prryurr rephion is necnsary:Wherc pressure regulation is no1 necessary, main liDe cxmctm ut nu only sufficient. but better than

water cxuaam are made of nonconusive maccrials rad moIt line bltm. ne prirmry tra5on f w t b i s is &I oil rad

(heir Life exceeds that of my steel or irm arm lbese Oil Ud water CXUaC(016 1TC baled in the dir- m b u h system rhcr the air wivn. Tbc proper disma should be at lust 25 feet w a y from the air receiver so that the air bar a chance to cool down sufficiently before

m o d of * impurities n o d l y found in the majority of air distribution systems. An extractor’s efficiency is wri- able rad is rclarcd to the t empram lad humidity of the compressed air. These units do not provide results as CffCUbdY air dryers, h-r. the& lower hitill C a t is a factor m sclectioa of alternative mum. One unit ail1 be required u ucb &-off point on fhe main line (header).

d i n g the UmCWI. TbV UC M e f f h UlCaI lS for IC-

0p.ntiar: The rollo%kg briefly dcrcriks OperUioDll ch.nacn ’SliCS of Common rypa of’exernon: 1. m e pLter uc used to forn Ihe lir S“ toch.nge

dinaiaD very rapidly causing the bmviu din panides to be dislodged and carried h g the side d s to the bottom of the extractor. Others incorporate a lead screw principle which creates a cydonic effea or a whirlwind rype of air mowment. This muion causes the havier pan ida IO be dislodged against the inside 4 1 s of the unit.

b. Another method is IO hive the air strike the cooler 4 1 s of the umaor’r oum body. This in cmbmcioa wiIb Ibe pressure drop resulting from air being used will -use water to condense out of the air.

c. Filters are employed to trap solid psrtides u well as absorb moisturt. Some of the different rypa of &ICK available uc:

-metal or plastic cylinders -high abrorbent dah -water absorbent chemicals

Selectlon Conrlderatlonr: a. Volume of rir bot the e x m n a uill be required to dean. b. Maxiium working prcssure on the umaor. c. Method of filtration and water extraction. d. Piping inlet and outlet size. e. Distance for Ibc compressor to the extractor. Note the

minimum recommended distance is 25 feet. The piping should slop towsrd the ccmpmsor lor best mlu.

-prous OI S i n t ~ d b m

MalnteMnce: T h e following are the requirements of a baric maintenance yrrognm:

a. Oil a d water extractors must be drained daily. under pres”. to remove impurities. If the umditims are ex- mmely m. hey may have to be h i d periodically

b. Extractors having filters must be disassembled and Ibc 6lter e l emi dcpned or -la&, otherwise the mount of air passing through the unit 4 1 be appreciably dud.

c. Maintenance schedules should be establishedlo.clcan.

d. 1! is good pnniee to keep apue air s a l s for oil d wam

duringibedly

dnin Ud @iUX frlICK U.pCriodic h l C d S .

cxmors on had.

W

E. Flltera Nlen m normally a mechanical means by which solid parti- des ue reu.wed fmm che air supply. Filter uniu normally do od re”c moimvc as it is a watu npot (gaseous) form ud will pass through with the air swam. The principle function of a iilter is to remove he solid parades out of the rir smam t h t may cause a malfunction of an air device or may damage the equipment. 1. Selcnion Considerations:

a. The vdume of air required to flow through. h. The maximum working prrsrurr. c. Met Ud outlet piping sue. d. Materials of consmction-corrosim mistmt. ctc. e. Si of film clement-this will determine how often it hs to be dcancd or rcplaccd.

1. The smallest size panidc it will filter out (retain). 2. Mvlouges:

a. Will filter out solids to a fine degree depending o?

b. LWI cost. E. Easy maintenance.

3. timitntions: a. Element must be duncd as conditions require, other-

w r e n mesh selected.

wise efficiency Ud rir flow will decnaw.

66 . _

Ty#uL OIL L WUER COALESCERS, AND AIR DRYERS CONDmOW MDlWToR 8-

H W

TlE ROD

FILTER

TUBE

RETAINER

S E N NUT

ExTRAclvR COALESCER

X AIR REGULATORS

A General Dmerlptlon An air regulator is 1 l r l e d m d . deviccwh*hrrhmsthcuniLl line airpresavcto a rpdficopcntingprasuc. ODfe thcopa- athg prcrauc is set. the regulator will autanariully cain this setdng. For a m p l e : if a IO0 psi main liac supply of air is to k reduced to .D operating prcsurc of 40 psi. then the air regulator wiU h.K to k yi u) m u a 60 psi dmp inthc sy- um. If the IO0 psi supply changa. the regulator will wtunati. ully canpensau br this change. Once the regutatom .IC yi.

any reduaim in prrsnvc will cpuv the reguluor to pro mole lir. if the p- increases. the regulator will pro Ius air. ’Ibe prrsnvc set in thc regulator will dways be consun1 Lrrspaive of the main BK Euctualioo. A regulator will NEVER pmvide higher air pressure than the air distribution system has to offer. The fdlowing dewrib the sequence of operatiom -ty turning the conml knob in a dockwise dimtion, the toll-

-the buaon p u s h against the regulating spring @re-baded). -the valve sum, in Nm. moves the valve away fmn its sea.

-air pressure an the regulated side increases, this prruurc p u s h against the diaphragm and regulating spring.

-when the air m Ihe regulated side is balanced, it then against the diaphragm and regulating spring causing the vPtvctorenua to its seat (dosed).

-as air is consumed from the regulated side, the mulunt pnxwc drop will m u an unbalance of folra (air pnsurc) against the diaphragm and thc spring caming the valve to un- seat ud. again. pas that mount of air needed to balance the m u m .

ml knob screw will push a button.

-air em ty thc seat into the regulated outlet.

H W

RnAINER

lV8E - DESICCANT CWLl8ER

R*lE

INSPECTION WINDOW

n E ROD

RETAINER

SEAL

STEM

DRYER

8. Qw L.l ppnr of each uc the YIDC, the diffpcnce b e i in the m y cbc body has beell drilled. Ih 6rst ud mod1 fo”Bl style is

ora9 tbc Iccad re&” 1 prcsult unk.

Air rcgulatocs uc desi& in NO diffcrmt wks The ”n-

referred to as a standard regulator. Swdnrd regulators are d y uud m oil and vnur exaactor reguhor crmbinaticms

Ihe wmd style is r e f d to LI a by-pss ~ g U h t ~ which has

m. By-prsr regulators uc wully nnployed LI the hnt regulator m prrra~ lank. when manifolding regulatm tqcthcr or even used as uke-offs from main air supply lines. Bypass regulators may be identified by i nduc ing air into the inlet pons msrlred ud observing if& air p”res h u g h wihut

W O rCguhrcd MltlCL5 md 8 b y - p for UUh h C pnS-

lirregulntion laking *.

C. Selection Condderrtlon 1. the d lor a standard or by-pas ngulator. 2. thc volume of air the regulator will k q u i n d to handle.

Nota: to &de Ior future necdr. always relea a regulator ltaving a capacity about 125% of your c m n t determined volume,

3. IIIC highest operating phcarrr the regulator mun conml. 4. the propcr size of gauge required lor the regulator. S. thc sire of pipe c” of inleu and outlctr.

D. Trouble ShootlIq 1. scc pall sheet pertaining to pur specific regullor.

61

2. Robkm: airlcrLzan of hde in rop of -. %J. AIR LINE LUBRICATORS A. Genom1 D08crlptlm The dctrimenul effect of oil in an rir line system bas been arcscd rcpcplcdly thmughout this Tniniag Bulletin. H- Qrr are ins- when i proper mount of oil d y atom- Lcd is essential IO the opentim of anaio rypcs of rir cools or

mts sorrosica. sizing of Qse tolcrure taring surfaces. .nd main& the rcrf iCacC O f ’0” IiUgS d vrlc hthirpurpac lubricuon CM be mound mora the oprrrt- ipgdevicc. built into the device (many a i r i r s hrvc this fa- m), mbeinrulledin C& airmtunjmuprr” of I& inler U, thc rir cod. ODK iubricnton in~ulicd d the propr M of lubsiutico is rmiouirud. they will pDvide autwaric l u U m u, equipment.

kmcdy: tighten lc~cln m bo~uwt Empc. If his doa w(

stop the l u k . it is likely that the diiphngm his been p”d.

3. Roblem: regulator grugc dimbs In rmin line preram.

4. Roblem: regukor will DO( rephte Rcmcdy: duo m .od stem or npLcc with new puu.

Rcmcdy: spring returning the n l v e stem is rusted or V r l ~ sum is held fast by comioo; duo puls a f f d or re- pl.ce u qltired.

Rcwdy: tighten scews m bonnei tlmgc, rcpLct Bukecm 1 l e c d g=k: m tbe d e r si& of the di.Pbgm.

Rcmcdy: mrkc sure ail supply is ”d m; check Io ree if

pre” air openud devices. huuduaica of this aMtid lubricant prr-

- 5. Roblem: regulator rinp or h u m

6. h b l e m : no air p i n g thmugh regu1oM.

rir passer k l y through oil d water eamctw, ICC Uut air is ruching the air regulator; inspect regulitor filter screen: dun 111 air passageways in regulator; replace or dean regulator fiur m n if required.

SIGHT DOME

8. S.leclion Conddomtlon 1.cuprrquindTormCippliacioo.

4. VOrLing praaue of the unit. 5. pipe inlet lad ouuu sia.

7. cup of lubrimlt quid.

I . UK cquipawnt quiring i lubricant will rscivc the cor- IUXl”t.ndcyp.

2.minimitarOdrrp.ir. 3. beau qmat@ efficiency. 4. rods and d e r air opentd dcvim my be stored and

slbsequeally urcd without cmccm IS IO oil sludge being crcaudinmetod.

5. 1ubric.n~ i re fed into the tquipmcnt d y when unit is oparting.

2. dumcofairtheunitmustp. 3. .mwllt Of hbIiCM1 R@d.

’

6. quantity of oil in the lubriutort rrscrvoir.

C. Adv8nt.90~

DUPCIIUQY

OASKET

D. Llmit8tbl8 1. it is iddilionnl piece of equipment that quires main-

2. ddr diffmnr weiglu oils IO spxific typr of air opcraud

3. nu dI rypa of lubriunt uI1 be uwd.

IeNna.

i r r

4. mervoirs may require hrqucnt filing when lubricant requirements uc high.

E. PlOC8UtlOMry NO108 N R REGULATOR 1. Using i muM-tool lubrkator thm is dways the danger

Ihc same system. Lubricating-maintcnmcc of the oil kvcl in such insmcs-is of primc mccm.

2. Keep air lines short; oil sludge my rccumulale in low

thlt me unit mly nul dry .nd damage to the tods using

rpau of bng rir Lms. 68

3. S k rypr of lubriunt rbould DO( be used u cbse oils will create paint drrishing problems. ochn rypc of lubri- ants arcb as mdy-graphite. sewing MchiDe or 3-io-1 oil

and surfaces. It is recommended that a sundard noa-

mam k &. 4. To function properly. lubricators mu1 be matched to the

aluipmcntt o&dr 5. Thc propcr.mount oflubricant is imporuntrrux) much LI

*rll u ux) little ullcrcote pmblemc. A good d e is toad- just the lubricant feed until a small of oil is prccpi- blc u the &ut pon of the cod. An -supply of.oil bas a teodcncy to create an "oil fog" which can k objcuiauble to popre wrking in dose proximity.

XII. GLOSSARY OFTERMS FOR COMPRESSED AIR SUPPLY SYSTEM ABSOLUTE PRESSURE is the existing atmospheric gauge pre~aue: plu atmospheric p""rc. At vp I d thc gauge pra- sm in pounds per squue inch plus 14.7 psi gives the abwluu'

ACTUAL CAPACITY of an air or gas compressor is the quantity of air or gns comprcrrcd and delivered. II is vsually expressed in cubic feci per minute (CFM) at intake pmsvrc and tempemure. AFTERCOOLERS ue d- for rcmaving thc h u t of can. prcsia~ of the air M gas afur ccmprcssion is rompletcd. They ue me of the mest effcujvc mras of mnwing moisnuc from canprcycd air. AIR RECEIVERS ue unks into which eclmprsed air M gu is discharged for the compressor. Receivers help eliminate

during intcrvrlr when the d e d Rfeeb the upldry of the crmplaun. COMPRESSORS ue machines designed br rompresing lir or gas from an initial intake pmsurc to a higher discharge P===. COMPRESSION EFFICIENCY is the ntio of tbe theorcciul horvplm to the larul indicated honepwr q u i d to can- press a dc6nite mount of gas. The thcorctiul pwr m y k cdculated according to the isothermal base or tbe adiabatic base ud the compccssion efficiency comspoldingly dchncd and up& in per cent. DISPLACEMENT OF A COMPRESSOR CYLINDER is che volume swept through by the piston. aillh proper deduction for the pistm rod. This is w a l l y c x p d in cubic feet per minute. DISPLACEMENT OF A MULTI-STAGE COMPRESSOR is that of the h n t stage only. since the same gns passes through dl stage in wria. DOUBLE ACTING COMPRESSORS arc t h a e in which crmprruia~ ULeS place m buh smlrer per moluriOn in a h canprasing element. FREE AIR is air at normal atmospheric conditions. Becaw the al t i~de . barometer and tempennrrc vuy at different locali- ties md i t different times. it follows that this term docs not mean air under identical caditicas. Considerable c d m hns existed icganiing the l ~ r m 'iiu air" and it hs o h k e n in- terprcted to k air at sea I d condirjans. namely at absolute p~sslrc of 14.7 psi and u a tempnturc of 689. This is na the

Cmuio ldditives wtlicil m y h g e crmin tyF6 of vrlr

&lagent automotive oil or the special oil *pod (or lir

preJaue: in pounds per square inch.

F u h i a l s in the dischlrge line ud also m u rrongc capacity

amain- of the rrpnsica or'* lir". d i n this TDBUllctirr t h e " m s a i r 8 t the rtmorpherk cadiuolu u me point W h the canplum is iatcnlled. HORIZONTAL COMPRESSORS have the compressing clement in a boriznnul p h . INTERCOOLERS uc dnica for rcmwing the heat of can- F b Of the & M PPI UmsCfvbVC SURM Of mUlU- nrgccanprraon. -

- LOAD FACTOR is the nfio for the m g e ccinprruor output

the". LOW PRESSURE ORIFICE E S T is a method of sccuntelv meawing the air delivered by a compmsm. It is the me& rrcognized the CanprrVed hUNte. MECHANICAL EFFICIENCY is the ratio of the indicated boncpwer in the ccmprcsing cylirdm to the indicated honepwr in the pawrcylinders, in the case of ncun driven or in- tcmal combuticn engine driven fanprcsson and to the brcak horsepower delivered to the rhaf! in case of a paver driven machine. II is cxpmscd in per cent. MOISTURE SEPARATORS arc devices for collecting and rcmovinp moisnvc precipitated h the air or ~ a c durine the - - . . proeas Of cooling. MULTI-STAGES COMPRESSORS PR those in which can- pressim from initial to hal prcrauc is completed in two or mon d i i n a steps or stages. NORMAL AIR has ken vuiouslydcfinod. In this bmk the tcrm rcfm to air with a 36% rdabVC humidity u 689. This may be mLtidned an " a g e d t i m of the .r" in I tempnte ctimuc 'Ibe &of spedfic hm~5 OT 'n" is I .3947 fornonnd air. Density is .075 Ibslf~.'u 14.7 k d m ? d 689. OVERALL EFFICIENCY is the prcdw of rhc comprcrrioo efficiency and the lncchNc ' 11 efficiency. PORTABLE COMPRESSORS ue hosi in which cach e m - prarina element consists of a oistca movinn back and fonh in ~ - i cy&. ROTARY COMPRESSORS uc Ihose having a m e mor or its cquivllent mounted eccenuicm in a s & q cuing. SINGLE-ACTING COMPRESSORS are those in which com~rrrtion uka olpce m but one smkc cer rcvdution in erch rompressing element. SINGLE STAGE COMPRESSORS uc thorc in which com- prrsrim frrm initial to final prrrarre is canpleu in a single step or stage. TWO STAGE COMPRESSORS arc those in which compression from initial to final prcrwve is completed in IWO dis- tirm stcpr or suges. VALVES ate clasribed in two distinct types. Mechanically operated valves depend for their opening and dosing on "e u d , ~ ~ ~ ~ c h v l i c a l means. They uc usually driven fmm the mnk shaf~. Their time of opning and dosing is fixed in eta- riOn to the mwement of the piston. Autaralic valves depend for .their opening and dosing entidy on p~aarrc diffcrcnca. In the CLY of the inlet valve. b e t w e n inukc ud cylinder p r e s " and in the case of the discharge valy, ktwcen cylinder and discharge prcsaya. VERTICAL COMPRESSORS haw the ~ n m c ~ i n ~ element - iuavmjcdpIMc. VOLUMETRIC EFFICIENCY is the ratio of the actual capacity of the compmror to displacement ud is expressed in per cent.

69

HOW Much Does An Air Leak Cost ?

LEAK

1/64

1/32 0 3/64

0 1/16 0 3/32

0 118 0 3/16

0 114

2

SCFM

.36

1.47

3.28

5.87 13.10

25.80

58.30

103.00

HP KWH $/DAY

.09 .07 .09

.37 .30 .38

.82 .66 .85 1.47 1.18 I 1.51 3.28 2.62 3.35

6.45 5.16 6.60

14.58 1 1.66 14.92

25.75 20.68 26.47

$/MONTH

1.95

8.23

18.42

32.72 72.58

143.00

323.00

574.00

$/YEAR 23.40

98.76

221 .oo 393.00 871 .OO

171 6.00

3876.00

6888.00

Based on 90 P.S.I., $.OB per KWH, 2-8 hour shifts, 5 days per week.

An arbitrary cos1 which varies with time 6 place.

<-

Material Supply

THE SPRAYING SYSTEM

A spraying system is an inter-related urembly ( ip ment that contains, conveys, and sprays liquid material; and which includes all of the control apparatus for operating this equipment. ' h e material supply portion of a spraying system consists of the container. the agitator, the pump, and the auxilia- ry components that filter and regulate flow of the driving medium (compressed air) and of the driven medium (liquid material). 'his bulletin describes the material supply equipment and discusses their use. operation, and maintenance.

1 . METHOOS OF FEEDING MATERIAL TO THE

Rint spraying systemi axe either gravity. riphon. or pressure fed. A GRAVITY FEED

Gravity reed preceded the present, and now more widely uud. pressure feed method of nuterLl delivery to the spny gun. ' h e main r q u h m e n t of gnnvity feed L that the container be vented so that atmospheric air cu~.re. p l w the material u i t is being spnyad.

SPRAY GUN

The gravity feed equipment is relatively inexpensive in Initial cost and in operation. The container can be refdled without interrupting the spraying operation because it is at atmospheric pressure. Howenr. this method does have some limitations. Viscosity and flow characteristics of the material directly affect rate of flow to the gun: s does how sire and how length. Row is also affected by changes in pressure head which will vary with vertical position of the gun and with material in the container.

The container may be of any convenient size with 2 gallons most common. Its location should suit the materkl supply requirementr of the gun, Wdng into account that resistance to materid flow increases with length of hose and with additional valves and fittings. Its location should also mate Nling convenient The container materid should be compatible with the contents. to avoid corrosion and chemical reaction. It should be lidded and the Hd should have a vent bole.

E. SIPHON FEE0

Siphon feed can be wed only with an air spray gun: and only with a gun in which the material is atomized outside the n o d e of the gun (in some guns atomization is internal). This is because in the siphon feed gun the siphon type"external &"air nozzle (we Fig. I ) rends a hollow column of moving air around the fluid nozzle and in so doing draws material out of the siphon cup.

. >.... " *..& '

. . <

?he siphon feed spny p n E O h w t s of a hand heid cup and p n ruambly that h used 8s a single unit. Since it h held in one hand by the opentar. Its weight, Including liquid material, has to be limited. Cup sizes nnge fmm 1 qt. capacity (maximum), for gencnl spraying, down to about 114 ounce (minimum) tor air brush applications.

Siphon feed spny guns usually operate at 30 to 60 psi. Fluid material flow is controlled by m adjusting screw on the gun. Fluid material viscosity is in the same viscosity nnge as SAE 30 to SAE 40 oil at room temperature.

1. ADVANTAGES ?he minimum apparatus of siphon feed equipment allows the installation of a spray system at low initial invert. ment. It provides the convenience of wing small q u o tities of material which can be changed easily for color or type. The spray gun, and its container of material, can be carried to work that is situated at remote places. The Only limitation to this would be hose length and air pressure capacity.

2. LIMITATIONS

In siphon feed. the siphon tube yur t always have its intake end submerged in the liquid material. In practice, however, this is not a limitation since the dogleg shape of the tube, and its adjustable position in the cup. allows aiming the spray gun through 180° from vertically down. ward to vertically upward.

The nozzle design and pressure range nee- for useful siphon effect on siphon feed guns limits the shape and size of the spny pattem. It also limits the rate of spray application to a maximum of 16 nuid ouncmper minute, m e weight of the siphon cup and its contents can be tiring to an operator if he is obliged to spray for periods of long duration.

3. MAINTENANCE & CLEANING

The cup gasket should be replaced whenever It drys out, becomes cracked, or otherwise deteriorated.

The cup should be washed thoroughly In a solvent that will cut Ihe paint. Solvents Ihnt might attack or react with the cup material. should not be used. After the cup is Ihoroughly cleaned, it s e m i as the container for a supply of clean solvent for Iinai cleaning flush-out of the S P ~ Y gun.

4. PRECAUTIONS

?he vent hole should be checked frequently to be certain it is open. The siphon cup should never be altered for the purpose of converting it to a pressum vessel.

5. ACCESSORIES

The following accessories for siphon cups M available from Binh:

llasticdisposible linen to facilitate clean-up and color change.

Cup agitator (roUry or trigger actuated reciprocating type). Seal-tight coven for short-term storage of paint in the cup.

. Cupstniners.

Siphon CUD

Mix Air Atomizing Nozzle

.d Punucots' Airbrush

72

C PRESSURE FEED

In thh method, materid ls delivered, under pmture, to the spray gun either by a pres" (compresed lk) container, or by a materid handling pump. I h e preuurizcd container delivers material one-way (deadend) to the rpny gun. ?be pump IIW delivers materid "deid+nd", or. It may be uud to drculate material continuously I" the c o n k e r , out to one or more spny rLltionr, and back to the container.

1. M E PRESSURE CONTAINER

?be prrsnvl container h a cup or tank containing the material that l a supplied to the spny gun under lk pres. me. I h e container and gun may be coupled together u one w m b l y . or. the gun may be hooked up to a con- k e r by hose.

Tbe tank M designed to withstand pressures up to the capacity stamped on the dde of each vewl. Pressure tank conform to ASME (American Society of Mechmi- erl Engineers) swIduds M labeled for 110 psig maxi. mum air pmnrre. Ihey nnge in capacity from 2 gdlonr to 250 gallons. Non-ASME tank ue nted and b l e d for 80 pdg maximum.

Resure cups are aizcd for 1 qt..and 2 qt. capacities. ?bey are n ted for DRSSUR capacities of lex than 50 F& and M so marked by the rkufrcturer. R e m &PI are non-ASME 'Ibe ASME tank ue e l t ined by the manufacturer and curg his permanent stamp. I h e pressure ntinp on contriners ue Invalidated when they M reworked by being belted, drilled into, or rclded onto. Mart city, ate, and I n d u e d safety codes require that pressure tank be ASME Ilkled. Such containen ue refsmd to u "code" tank. ?be lk presswe capacity for which pressure vessels M nted must not be exceeded because Its Wiure under pressure could be harmful to personnel. All pressure vessels rhould be quipped with pressum limiting controls.

2. OPERATION AND CONTROL

I h e delivery of compressed air supplled to the container ls controlled by a pressure re-tor. k u r e control, together wlth selection of nuid n o d e orina size, and adjustment of nuid now valve, provides control of n t e of now of material from the spray gun. Fluid pressure mgulaton are used in the nuid lines when more than one spray gun is fed from a single tank.

3. ADVANTAGES

A simple and low cost controlled way to force feed material to a spny gun.

Capable of delivering a wide nnge of materials. Simple maintenance - no momg parts.

Utilizes alr pressure which is already available in a plant or at the contranor's job site.

Spny guns supplied by hose from a container my be operated in any position.

73

?hc prenwe eont~inor h capable of handllq l y e num. ben of rpny guns; the only Umitation h that It be dzed and adequately quipped. Origind material container or an inner-liner can be p i m d h i d e the prczrure nucl IO ntinimize time lost in clean.up. I h e presswe vcrrel tenes u a sealed storage container for the material.

Fluid

U

muvn M

4. LIMITATIONS

Container refilling mtermptr the work by mrkinp it necessary to depmrurize the system. llme lost in dean-up during color changes. However, thii can be minimized in set-ups consisting of only I few colors by having a separate tank for each color. Weight of large tanks and contents require lifting equip. men) far handling and relocating. Ressure containers M be used only in a deadend (one. wry now) system, (pumps M required in a circulating system where materid is retumed to the container). Containers must be kept vertical to avoid sloshing, splashing. and frothing of the m a t e d in the container.

Ressure capability is limited to the rating of the vessel and to the air supply cap8city of the plant. 5. CONSIDERATIONS FOR SELECTING PRESSURE

VESSELS

The volume capacity of spray gun pressure vessels range from 1 qt. to 250 gallons. In general, pafnting contrac- tors and industrid maintenance departments find the 1 qt. to 10 gallon sues useful. In-plant production painting, departments. in continuous flow manufacturing operations. select capacities up to 250 gallons. Thk type of container to be selected s h d d also take into m n t material viscosity. Heavy materials such as SAE 50. oil. or heavier, must have bottom cutlet containers.

Another consideration is whether or not ingredients in the material tend to “settle out”. If so, a container with an agitator wiil be required. If the matelial is corrosive or reactive with certain met- als. the tank may need to be stainless steel or specially lined. If a variety of materials pre being used, it may be desirable to use removable liners. he in-plant compressed air mrCe must have the pies- sure and volume capacity to meet both the pressure container and spray gun requirements. 6. START-UP PROCEDURE

Connect air hose from the air supply to the inlet side of the regulator on the container lid. Check d m i o n of air flow. “Back off’ regulator to prevent air flow into the container. Open relief valve. Connect air hose from air pressure regulator to the S P r s Y gua. &ect fluid hose f” container to spray gun. Remwe lid from container and pour in a small quantity of compatible solvent (this material is to be used as a test fluid). If container is a pressure cup. at this point connect cup directly to the spray gun. Securely tighten lid. Tighten clamps uniformly, going around several t i e s . and turn on air supply to container. Listen for air Am from relief valve. Close relief wlve and set air pressure level at regulator. Check air and fluid lines to spray gun for I&. Remove solvent from pressure container (see shutdown procedure) and hi1 with material. Do not fill the pressure tank to its brim. Leave several inches of air space to permit .proper operation. The materid will flush the solvent out of the Auid hose leading to the spray gun. 7. SHUT-DOWN PROCEDURE

Close air supply valve to container. Release air pressure in container by opening relief valve. Leave relief valve open. Do not use safety ”pop“ valve on ASME tanks. I t is a violation of code to use safety relief devices for normal operating functions. Open container to the atmosphere. Loosen air n o d e on spray gun. Hold a piece of wadded cloth over the air nozzle and trigger the spray gun. Atomizing air pressure will force the material back down the hose into the tank.

R e m m the remaining mated. Clean the container and pow in a small quantity of suitable solvcnt. Wipe off .spray gun, container. and hoses with solvent dampened mg. Remove air n o d e and clean as necessary. (Caution: Do not use wire brush nor metal probe in air holes). Replace lid and pre.suri7.e the container. Tum off atomizing air to spray gun. Squirt solvent through spray gun into a suitable waste container: “triggering” spray gun until solvent comes through clean. ‘Blow out” solvent f” spray gun, container, and hose. Coil the hose. In some instances it may be desirable to keep the system wet by filling it with a small quantity of petroleum hsed solvent such as kerosene. This prevents hardening of any residue material. ABOVE ALL KEEP THE EQUIPMENT CLEAN. I. MAINTENANCE Pressure container head gasket s h d d be reolaced when air leaking occurs around top of container kith clamps HAND TIGHTENED. CLAMPS SHOULD NEVER BE WRENCH TIGHTENED. When unable to control fluid pressure. check air I’eguIa- tor to sn that it does not “climb” above ”set” pressure. The spray gun will “spit” when the fluid pick-up tube connection is lwse inside container, Remwe tube. Seal with D Uue& compound such as pipe dope or teflon tape. Replace tube and tighten. &place gaskets or sepk to stop air leaking out of container d agitator M. Tighten cap and replace gasket to stop air leaking -d quiek-fill cap.

j I i I Fluid Pickup-

Tube i

S. PRECAUTIONS

Never exceed the pressure rating of the container as marked thereon. Never make any physical modifications to a pressure container. Never use corrosive materials in a container not designed to handle such materials. Never remove the safety relief valve. Attach a ground wire for added protection from static electricity.

74

,

Never we name to clean I pmrure contrincr. Use only paint stripper or solvent. Always tighten clamps on a pressure container by band, two at a time, diametric& opposed c h p s .

Never tilt a pressure container while it contains material. This fllls the air regulator pawages with m a t e d and causes unnecessary elean.up of the lid w m b l y . Never position a container lid so that oil drains out of its agihtor drive gem box.

Never attempt to open I pressum container without flrst venting the pressure.

Never use high pressure air or a hammer to loosen a container lid. Remove lid by prying with a bar gently and only at clamp points. Always refill the pressure tank through the quick-fill port whenever possible. This minimizes frequency of removing the lid and thereby extends the life of the lid gaskets and clamps. Always clean spiiied paint off the tank rim before in. stalling lid. Keep rim clean. 10. ACCESSORIES

Pre-formed plastic disposable liners for 2-gal. non-ASME and for 2-. 5-, B 10-gal. ASME pressure tanks.

Multiple air or fluid outlets for muiti spny p n operations.

Air control assemblies available with ule followins com. twions: No rqulatoa (air must be controlled from I remote W W ) .

Main Air

1 Air

Remote Air Control -TOP Outlet Container With Hand Apit.10r

One regulator to regulate air only into the container.

Single Regulator Air Control - TOP Outlet Contamer

Two rcgulator-control: one to regulate air into the container; the second, IO regulate air to the spray gun.

\

Double Replator Air Control - Ilottom Outlet - With Follovrcr Plate

7s

Agitator assemblies: Hand, air motor or electric motor driven.

Fluid stminers for filtering the material as it leaves the container.

Caster bases for mobility of the pressure container. Non- sparking wheels available.

Inner liners for containers to minimize labor in color change and clean-up; may be plastic. galvanized. or stainless steel.

"Off-set" funnel fluid strainer for adding paint to the container through the quick-fill inlet.

D. FLUID HANDLING PUMPS Fluid handling pumps are available in a wide variety of designs to meet the requirements of various applications. Each type of pump hu its own performance characteristics which make it suitable for specific uses. Pumps fall into two major classifications: hydrndynamic or hydrostatic. Hydrodynamic Pumps Hydrodynamic, o r non-positive displacement pumps, a r e primarily used t o t ransfer fluids when minimal resistance to flow is present. They provide smooth continuous flow of material. but their output is greatly reduced as resistance increases. These pumps continue to run when flow is completely stopped. Two main types of hydrodynamic pumps are centrifugal and turbine. C.ntrifug8l Pumps Centrifugal pumps use a rotating impeller to push the material from the fluid inlet near the center of the im-

peller to the fluid outlet near the outside. These pumps M m m a high volume (1,000,000 GPM) of marcrial at lmv pressure (2,000 psi) and can handle either abrasive o r corrosive materials. They are usually not aelf- priming and can only be used to move low viscosity fluids.

Centrifugal pumps

Turbln8 Pumps Turbine pumps use a high-speed turbine to move low viscosity materials at moderately high pressures (up to 500 psi) and moderate flow rate (200 GPMLThey are designed to handle non-abrasive, low viscosity materials and are normally not self-priming.

Turbim Pump

HydmNtic Pumps Hydrostatic, or positive displacement. pumps deliver a given volume of material for every cycle or revolution. Their rate of delivery depends on cycle rate or speed and the amount of displacement per cycle or revolution. Hydrostatic pumps are available in a variety of designs, including gear, helical screw, flexible impeller, rotary vane, peristaltic, piston, and diaphragm.

Gear pumps use two meshed gears to draw material into the pump and discharge it. Gear pumps can dispense medium volumes (3.000 GPM) at pressures up to 2.000 psi. They can handle viscous and corrosive materials but should not be used with abmive materials and should never be n m dry. They are self-priming and are usually bidlectional.

G88r PumpS

n

HIIiul8anr Helical acrew pumps uae I drive screw and meahing idler screw to create continuously moving poekeu dong the u i s of the pump. These poeketa draw materid into the inlet and puah it out the outlet. Helical a m pumps can develop fluid pressures to 550 pai and volumca to 270 CPM. They provide smooth, continuous flow and can be rued with corrosive materials up to 1.000,OOO centipoise viscoaity. They have excellent suction lift and are self- priming but should not be run dry.

krh0)tlC Pump. Periatlltie pumps we a aerier of mllen or cams to push the fluid through a piece of tubing. The fluid being pumped comea in contact with only the inside of the tubing, which eliminates contamination of the fluid and compatibility problems. These pumps can pump abrasive or corrosive materials at a rate of up to 300 CPM at pressures of 100 psi. They are self-priming, can be run dry, and can handle marerial viscosities up IO l0,oOO centipoise.

Helical Screw Pump

flaxibla Impdler Pumps Flexible impeller pumps make use of the changing volume of chambers to drnw materid into the pump and discharge it. They can deliver volumes to 300 GPM at pressures to 100 psi. They can handle viscosities up to 1,oOO centipoise as well as corrosive materials. They are self-priming but should not be run dry.

Flexible Impeller Pump

Plston Pumps Piston pumps use a reciprocating piston and a series of check valves t o draw fluid material through the inlet into a chamber and force it out through the fluid outlet. These pumps can deliver volumes of material up to 3.000 CPM and extremely high pressures in excess of 75,000 psi. They are self-priming and can handle high viscosity materials up to 1.000.000 centipoise. Piston pumps can be used with mildly abrasive or corrosive materials.

Rotary Vane Pumps Rotary vane pumps use vanes which slide in and out of a mtor to form chambers within the pump. Because the mtor is mounted eccentrically within the cylinder, the chambers become larger and smaller as the rotor turns, which draws material into the pump and discharges it. Rotary vane pumps deliver medium volumes (100 GPM) of material at pressures to 1000 psi. They can handle mildly abrasive or corrosive materials and viscosities up to 10,OOO centipoise. The sliding vanes compensate for wear. These pumps are self-priming.

Diaphragm Pumps Diaphragm pumps are one of the oldest pumps used by man. We have progressed from animal skin dmphragms through mechanically driven single diaphragms to air driven double diaphragm pumps. In the past 35 years. design innovations have made the air driven double diaphragm pump one of the most reliable. versatile broad application pump available.

Ir

Diaphragm Pump

H-High M-Medium L-Low Y-Yes N-NO

78

1. THE RECIPROCAnNG PISTON PUMP The reciprocating piston pump is the type most commar- ly uaed in a moterial spraying aystem. It consists of tw d o n s : the power section and the fluid section. The power section either can be an air driven or hydraulic motor driven piston thnt is d i t m e c t e d to the W i d handling "Euid" pism (* be'w)* Or & "lMd" piston can be driven by an electric motor thrpKh a piston rod and crankshaft linknge system.!

B i n h Comet pump q d Binka Super Bee pump outfit are examples of air dnven and electric motor driven reciprocating piston system respectively. .. NOMENCIA'LIRE me mgement of eomponenrs in a recipmating piston pump and thew sequence of operation are shown %hemtidy hiow.

Pilot Valn Pinon- Pilot VaIw Piston7

Air In d

Air Exhaust

Pinon Rod

T h r M Packing

Prruun Onchug*

Flu16 Piston

Flwd Cylinder

Pntm Bad" V.IW

Inpke Chambar

FWI V l l w

ChamMr

Mitend In

Vmmd Pilot A W - - - - Exhwrt Air - -- A,. Input

Air Motor Driven Reciproating Piston Fluid Pump

79

pomacuon

The air powered piston-cylinder "motor" ansembly including valving, rod, seals, etc.

The electric motor, gear reducer, crankshaft, and piaton rod assembly, Fluid Section

I b e pistonsylinder awmbly driven by the power section that pressuredelivers liquid material to the

Air Piston

The reciprocating member in the power section. ?he piston is poweted by compressed air.

Air Valve

Directs the flow of compressed air altemately and. in correct timing, to each side of the air piston. Acruator Trip-Rod

Controls the sequencing of the air valve. It is directly connected to, and is actuated by, the air piston. Fluid Piston

Tne reciprocating member in the fluid section. ?his piston is directly connected to. and driven by, the air piston. Piston Rod

l%e member directly connecting the air piston to the nuid piston. Air Motor W i n g and Throat Rdting Rubber, leather, or synthetic mterid serving to pm- vent leaking of air md nuid out of the power and fluid sections at the piston dDd: Air Cylinder and Fluid Cylinder ' h e tube-like chambers containing the air piston and fluid piston. They are appropriately valved IO as to receive and discharge air and fluid respectively. Top Cap and Bottom Cap

T n e end members of each cylinder that close off the tube to form chambers. Cup S a l and Piston Body Rdting

Rubber, leather. or synthetic material nxed to the peripheries of the air piston and the fluid piston, respectively, to prevent air and nuid from leaking past the pistons. Intake Chamber

h a t e d in the nuid cylinder. This chamber receives fluid from the material supply on the upstroke of the nuid piston.

Foot Valve

Revents e m p e of fluid material out of the intake chamber on the downstroke of the fluid piston. Piston Body Valva

Controls nuid flow from intake chamber to pressure discharge chamber in the fluid cylinder.

wv gun.

Roun Discham Chambn

h a t e d In the fluid cylinder, this chamber receives nuid from the intake chamber on the downstroke of the fluid pirton.

RIM -on Compressed air enters chamber above piston. Piston moves downward.

At end of piston Stroke. lctwtor triprod reverses air idve which: Stops flow of compreued lir to upper chamber. Aliowa upper chamber air to exhaust to atmosphere. Wows compressedair to enter chamber below piston. NOTE: Switch-over of air flow from top of pirton to bottom of pistonis ahNpt and occwr instantaneously at g& of piston stroke. It is not related to movement of the piston but, nther. to P- of the piston. This mode of valve action minimizes the time during which pressurized lir is flowing simultaneously to top and to bottom of piston.

Piston moves upward. At end of upstroke, actuator trip-rod revems air nlve which stops flow of compressed air to lower chamber. AUows lower chamber air to exhaust to atmosphere. Mows compressed air b enter chamber above piston.

Piston moves downward. I b e repeating cyde of the power section describedabove is olled the reciprocating power rtion. Ibis r t ion is h.nrmitted dimtly. by piston md connection, to the piston in the fluid section of the pump. I b e '&rarting power stroke is alled "double-acting" k a u w the air piston is "driven" by compressed air on the downstroke and llso on the upstroke. I b e speed of mciprocatlon is controlled by n te of now of pmsurizld air into the power section. An air regulator in thecompressed air h e isused for thii control function. For a patticulu nte of flow of pressurized air into the power section, the speed of miproation rill increase with a d m l v in resistance of now of the mated out of the spny gun, and vice vem.

b. WMPOPERAnON

fluid Section Upstroke At the piston moves upwud. it dnws m a t e d through the foot valve into the intake chamber.

As the piston moves downward. prrsure OD the material forces the foot valve to d w and the piston body valve to open. Continurd domwud movement of the piston forces material through the p ' d body d s e into the p m r e dischw chamber.

At the piston again moves upwud, pressun on the material in the discharge chamber form the piston body valve to dose. Thi action rlro pushes the material out of the dischage chamber into the supply line to the rpny gun and, simultaneously. again dnws matexid into the intake chamber.

80

Ar the piston again moves downward. material is f o m d into the direhuge chunber from the intake chamber. u described above.

A highly desireable feature of pump opention h to Iuve constant, noniurging, nte of flow of material output. The pistoniess pump shown in section "D", for example. would deliver material at a flow nte that is u constant u the nte of flow of compressed air into the pump. During opention of the recipmating power pump (des. cribed above), material would flow out of the spny gun only on the upstroke of the fluid piston. On the down. stroke, material would NOT flow out of the gun because the motion of the fluid piston. and its compression effort, are in a direction opposite to that of the material flow. However, through ingenious design, this opposite compression effort has been made to wist flow of material out of the gun rather than to retud it. This mistance serves to maximi= uniformity of flow and to minimize surging. This was accomplished by sizing the diameter of the pis. ton rod to a dimension that would make the volumetric capacity, swept by the fluid piston, twice as iuge in the intake chamber u in the pressure discharge chamber. Thus. one hair of t h e material entering the pressure dm. charge chamber from the intake chmber, on the d o m - stroke, remains in the pressure dischuge chamber. The other half, also entering the pressure discharge chamber, must, necessarily. move out into the spny gun SUP ply line. ?hen.on the upstroke. the remaining one half of the m a t e d moves into the supply line. Therefore, the m o u n t of material that is moving out into the supply line is the sune on the upstroke u on the downstroke. c. PUMPRATIO The term "pump ntio" derribes pump perfoomunce. It h useful in comparing one pump to another and in ap- praising the condition of a pump during its working lifetime. "Pump ratio" is a general term. It un refer to theoretical pump ntio, stalled ntio. or openting pump ~ t i o . These latter. more speciflc terms. should be rued when discussing pump ntios in order 0 avoid misunder- standing. THEORETiCALPUMP RATIO is the ntio of "efreective" area of'the air piston to that of the fluid piston (not counting piston rod). "Effective"uea is the contact m a of compreswd air on the air piston (and of fluid mated on the fluid piston).

! i

Ratio

STALLED PUMP RATIO relates pump nuid pressure to & p m m when the pump h stalled out. SWed pump ntio is less than theorctial pump ratio b c u w of friction within the pump. OPERATING PUMP RATIO relates fluid pmsure to air pressure during the time that a pump is stroking. When a pump is stroking. under constant air pressure, the stroke nte will increase if Spray gun nowle size is increased. or if material viscosity is demased, or both. Under these "if" conditions. at constant air pressure. mterial nte of flow will increme because resistance to flow h u decxeued. d. ADVANTAGESOF RECIPROCATING PISTON PUMPS They cm handle a wide variety of fluid or semi-fluid materials. They have a wide range of operating pressures. They cm draw material directly from the original container. Material can be circulated to keep pigment in suspension. They M be controlled to deliver material in large or r d i measured quantities. or at random demand. They permit fast color change and clean-up in small ryrtem* lhey cm be used d e i y in hiurdous locations because they ue air operated. a. CONSIOERATIONSWHEN SELECTING AIR-OPER-

The customer flnt must know what his maximum R- quirements ye concerning nuid dkharge nter (gallons per minute) and p-re (pounds per square inch). These hc ton ue reiated to fluid nozzle orifice size.

ATE0 RECIPROCATING PISTON PUMPS

After determining the required fluid disdruge rate and pressure, the appropriate pump fluid section and corresponding power section can be selected from manuhc- hued charts and tables. These tables -late fluid dis. durge nte (gallons per minute), pump speed (cycles per minute).and comprerced air requirements (cubic feet per minute) at various air pressure levels (pounds per squue inchi.

The following general guide rill sene in relecting suitable theoretical pump ntios to handle adequately the various kinds of materills encountered in spny painting:

Selections should always be on the high side. Ovemze pumps will have a longer life and, genenlly. wiii suffer less wear m d will require less maintenanee. Note that material ingredients, viscosity, and distance to be pumped. are facton in selecting pump size.

THEORETICAL PUMP RATIO Uquid tnnrfer 1:1 lhin & medium viscosity 21 (dmllU to SAE 10 oil)

Horizontal. long distances 21 plus Horizontal, short distances

Vertial rise (0.5 p81 per 1'-0" rirc for rater) Medium & heavy sircoslty (slmllU to SAE 10 oil) Materials that contain short fibers or sand Nlen Heavy Nlers E l to 101 Long horizontal distances Vertlal rises Hot airlev spraying ' 17:l Industrial coating materials 30:l at room temperature, such as for general maintenance. Extrusion materia 6 1 to40:l Difficult to atomize materials f. OPERATION & MAINTENANCE

4:l to 6:l

sonup

Set pump in a solvent compatible with the material to be used. Run pump In solvent 10 u to nwh it thoroughly. Take pump to Its sW1 pressure. Check for leaks in the system either externally or i n t e d y . If the pump does not stall and there uc no extemd leaks, make sure the back pressure valve (if any) is dosed. Continued failure to sWI Indicates that piston packings or check valves are leaking. Shut down pump, relieve pressure and =pair u needed. (see p u t sheet for instruction dealing with your model pump)

When pump stalls correctiy, mmove from solvent and place pump in the material container.

M o w pump to dircharge the solvent used In the start. up procedure and begin spray opention. During Spny Operation

The pump delivers material to the spray gun on de. mand; the more material required the Cuter the pump will opelate.

Operate pump a t the lowest possible pressure that will deliver the quantity of material needed or the atomi. a t i o n required. Keep pump filled with material at all times. Do not let pump draw air or lose Its prime. Ovamight Holding Practice An amptable ovemight holding practice is to allow the pump to circulate material slowly through the pipe or hose line from container to spray gun and back again. This holding practice must not be used with materials that "set-up" through a tdyt ic , or chemical curing, or which tum abrasive or corrosive. The ovemight holding period should not exceed 16 houK.

Shut-Down Roadura

With pump running at slow speed remove it from ma. terial container. and let it pump air just long enough to empQ fluid section. Race pump into container of clean solvent and circulate solvent through the pump back to the container. Repeat this procedure with dean solvent until pump NUS clean. Several "short" nushes ue more effective Uun one long flush. Remove and clean any fllteers that may be in the system. Rslacemble Nters.

KWD svstem "wet". Fill pump with an oil base solwnt or & &en plnstidsu, such Di Octyl Terephthalate (D.O.T.P.) or Tricresyi Phosphate (T.C.P.). This will keep parts lubricated and AI prevent any residual m a t e d from drying and hardening inside the pump and causing subsequent damage. Wipe down 111 exparcd p u t r of pump with solvent dunpened rag. Lubricate air motor with a light machine oil or T.C.P. A few d r o p in the air inlet is sufficient. Caution: Do not use oils that contain silicone. Grease the fluid section If it is equipped with a grease

Store pump with the piston in the muimum down position; keep upright in storage.

g. ACCUMULATORS IANTIPULSATION CHAMBERS1 The p r e s s m applied to material during repeating cycles of a recipmxting power pump, varies as shmn.

Tbe pressure on the fluid reaches I& muimum level very quickly at the s t u t of each stroke and material is forced thmugh the system. The pmsure holds constant throughout the stroke. At the end of the stroke there is a m e w n r y t drop In fluid prruurr u the piston changer h t i o n in order to commenrr the rem stroke. During t b i ~ very brief period, a drop in premue is experienced at the spray pn. lhir lnercue and d e " in pressure is d e d m e . Surging Is undesirerble because It show up visibly on the f i e d paint surface u an uneven mating. To some extent, surging M be conuolled by fluid prwure regu. W n , par t idu ly if the p r r u m on the high side of the mfulitor is considerably higher than that on the low side. However, If the high side pressure is only slightly higher than the pmture muired at the spray gun, surgine at thegun will bemorepronounced. A common way to minimize surging is to use an accum- utntor. Essentially, this device, is a res- ewoir of stored-up material. under pressure. The pressure may be supplied by weights, compression springs. or compressed air. Tbe pmsurr In the accumulator is developed during the mrin portion of the pump stroke. %en, during the inter. vd that the pump is reversing Its stroke. and normal line pressure momentarily drops. the stored up material will be fed into the line to cover the brief intend of pump depresuriution.

ntting.

82

U p n I O b Uptroke Umtroke Sun End

Downstroke Oownnmk.

ASCumuImOr

3. PRECAUTIONS

Never e x m d the manufactured spcei5ed muimum d e livery ntig of the pump. Never use excess air pressure to drive the pump. Exces- sive speed will cause undo we= on the pump and will wute material.

Always check material to mlke certain it will not d m q e the fluid section of the pump. For exampie: Water bued materials require corrosion resistant puts in the 5uid section. Materials that contain strong solventr may require special plckinting. Materials which contain Nlen or abruives should be handled by a pump with a large-volume delivery capability. Such a pump will run slowly and thus will have minimum wear in the fluid seetion. Hardened components may be used In the pump to further minimize weu.

Always supply the pump with an adequate volume of air to do the job. 'Ihe air supply hose should be of sufficient inside diameter to handle the zequired air volume at the available supply pressure.

Keep pump lubricated u recommended by the manuhc- turer. One method of lubrication Is, periodidy. to pour a small quantity of light oil or T.C.P. down the incoming air line to the pump. Be certain that the oil does not contain silicone and that the b a u and intemrlah motor parts will not be damaged by the lubricant.

Pump quipped with dpbon tubes must be kept "wet" and must have dl their connections tight. W p u m p ahould be eleehidly grounded to prevent the .ceumulation of static electricity which could spark m d cause fits. Use only " e t hoses and 5ttings on pumps. W e cer.

Wn they will wort safely under the pressures. tempen- hun, degm of rough handling, and other conditions they are subjected to.

4. ACCESSORIES

Strainers and Nte~ at inlet to. and discharge from, the

Alr regulators to control air pressure to the pump air motor and to the air atomizing spny gun. Agitators for mklng the material to prevent settling. Uquld p ~ u r e regulators to prevent buildup of stall pressures and thereby avoid surge of material when the spny gun is higgered Anti-freeze ink tors or oilen installed in the alr Unes to lubricate the &,motor and prevent freeze-up.

Mixing tanks and standpipes for mounting circulating pumps for miring, distributing. and storing large volumes of matef i . Accumulaton to reduce 5uid pulsation and assure uni- fonn spray pattern when using air operated reciprocating

Manual presture relief valves to bleed the line of high P-. Intemai drum strainers for suction feed from drum. E. TYPICAL MATERIAL PUMP INSTALLATIONS

pump.

p u m p

1. "DEAD-END" NONCIR~ULATING SYSTEM

'Ihe dead-end system delivers matefi on a one-way trip to the l pny station, either neuby or remotely located. It is the m a t common type of pump Instahtion. It gives a qlulity linwl rltb materials that do not settle out and that do not requite heat. The spny gun material hose is hooked up directly to the pump (see below). With eonvent id air atomizing equip ment. a Sseond how supplies the atomizing air to the spny gun. With airlesa spny, d y one high pressure hosc is con- mtcd to th rpny gun.

Alomiz,na Air HOU .

Non-Circulating Systems

84

2 CIRCULATING SYSTEMS The circulating system moves material continuously through a closed loop of hose or pipe, through one or more spray stations. and back to the material supply container. The spray station may be either nearby or remotely located. The arculadng system offen a number of advantages: The clored loop drcuhw system M be provided with heaters and material m i r i n g agitators that will insure holding comct applicadng- tempenhues m d prevent settling out of materid ingredients. lbis erpabillty d o a s spny application of I widevariety of mated.lr. including wphlstlcated ones formulated with exotic ingredients. to provide particular coating fllm properties. Various subputc may be painted at different spny sa- dons and yet have perfect color match when w m b l e d because they ue supplied and sprayed with the identical paint. F. FLUID FILTERS

A fluid fitter is used to remove thou particles from the material which would contaminate the Gnat finish or plug the fluid nozzle orifice of the spray gun.

1. CONSIDERATIONS IN SELECTING A "FILTER"

a. FILTER TERMINOLOGY Mah 'Ihe number of openings In a linear inch. Sunen owing

?he s i te of the r m n holcopening measured In thousandths of an inch. Microns l b e unit of measurement for putlde size. It is equal to one thousandth of a millimeter (.001 mm). 25.4 microns equal one thousandth of an Inch (.001 In.). Particles Iaqer than the micron ndng of the fluid filter cannot p a s through the fiiter screen. Filtering am h a of m n expoxd to the material flow.

b. SCREEN SIZE REQUIRED FOR A PARTICULAR MATERIAL

Screen Opening Mesh Microns

Metallic paints and primers Solid colors Sealers and solvents Low pigmented fluids BufGng compound Mrttics and sound deadenen Mrttia containing long fibers

.009 60 228

.005 100 149

.003 200 76

.002 325 43

.020 35 500

.030 Perfonted mew

.050 screen

.030 "Stab" s e m n

.040 openinjp. Made

.050 by stabbing holes into sheet meW 10 L1 b produce bum.

I h e "um prrirurr ap.dty of the filter housing l b d d be greater thm tbe mrbg pressure of the ryrtcm. I h e degree of comdveness and abnrivrncu of the fluid to be handled will determine the type of mated used in the filter houring and element. 2 MAINTENANCE OF FLUID FILTERS

Experience will establlsb a best rminterunce schedule. Once established. It should bf followed

Nten must be cleaned regularly. Nten should be inspected when the following conditions become noticeable: Matedal flow is sluggish or excessive pressure is needed to deliver the required material. This ndrmally indicates the Nter requ!aes cleaning. Some fllters automrtiuUy indicate need for cleaning.

mal Iinish is rough, p i n y , or dirty. This Indicates the filter element is either b m h n or being bypassed.

A comet p u t aheet and an adequate supply of span putc should be stocked.

0. FLUID PRESSURE REGULATOR

A fluid pressure m a t o r is a device for controlling the prnsure of Guid flow to the spray guns. It is mounted on the dischuge side of the fluld pump as dosc to the rpny guns as is practicable, Ruld p m rrpulatonue sized recording to the degree of eontml m d to the mgr in prnrun that is desired For example: A rpnying.opendon bas a pump capacity

. of 160 pdg. lhir "vm pressure can be regulated so that the spny p n rrclivn fluid materid at from 3 to 55 psi& or, with a d e r dze regulator, It M receive fluid material h m 1 to 12 pslg. For my wtthg of the larger apadty regulator, adjustment in premve un be made lo incremerib of approximately 1 pig; of the smaller, approximately 1/4 Mg. 1. OPERATION OF A FLUID PRESSURE REGULATOR

Ibc setting of regulated prrsrure level Is accomplished by MW adjustment of spring c o m p d o n against one side of a diaphragm. Fluid pressure in the Une, on the outlet d& of the regulator, prrrses on the other side of the dhphngm balancing the compression spring load. 'Ihe movement of the diaphragm, caused by a change either in spting load or in outletaide pressure, controls a needle nlve oriflm which, in turn, controls material flow tbrougb the regulator. An inneve in outlet&& nuid pressure (as when turning on one of v v e d spny guns) d l unbalance the dia- p m load. This will compres the spring and cause the diaphragm lo move and to decrease the am of the needle nlve oriflce. Fluid flow through the regulator into the r p n y gun supply line will then be reduced as will be the nuid p " e .

85

Id

Fluid Re

1

- 1n-Llna Filter

Circulating Systems . 86

“dl i

8.d: Prarrura Regulator

2 CONSIDERATIONS FOR SELECTING FLUID REG- U LATORS

What is nuximum required volume flow nte of matedd?

What is maximum required working pre*iure nnge and pressure controi sensitivity of the system? Select 0.12 Ibs. for the delicate control required with electrostatic spnying or pressure sensitive fluids. Select 0.100 Ibs. for normal spraying pressure control. Special high pressure regulators ue requlred for airless spnying. k the material to be hadied by the regulator c o d v e or abrasive? Q h t is the pipe size of the circulating system? What will be the orientation of the regulator during open ation? Vertical, horizontal, etc.? 3. PRECAUTIONS

Bypass valve must be closed when regulating material PRYUre. Never “blow back” the regulator unless the bypass valve is open. Material supply filters should be installed on the inlet side of the fluid regulator to prevent material build-up on the regulator valve seat and stem.

Shutoff valva should be installed on both the Lnkt side and on the outlet side of the regulator to permit servidng the regulator wiqout dosing down the entire system. Never exceed the recommended working pressure of tbe regulator.

The regulator should be l w t e d as dose to the spny gun as pcssible.

Read manufacturer’s instructions pertaining to opention and maintenance and follow them faithfully.

H. BACK PRESSURE REGULATORS The effort required topush fluid material through 8 spny gun nozzle is supplied by the reciprocating power pump. In a “dead-end” material supply system, the pipe line be. tween pump and gun has oniy one outlet, the gun node . All of the pressure in the system, therefore, is acting at thegun nozzle. None is lost (discounting friction loses). In a “circulating” system. on the other hand, thew is 1 “retum” pipe line to the material container. The free flow of material out of the open dirherge-end of the retum line prevents the buildqup of pressure in the line that is necessary for pushing material through the spny gun nozzle. In order to retdrd this free flow of material, a “back. pressure” regulator is inserted into the retum line down. stream of the several spny guns in the system. This allorr pressure to be built up and maintained in that portion of the pipe line supplying the spray guns. and, at the same time, allows material to be retumed to the supply container in recirculation. The back pressure regulator (see page 18) is adjustable and Drovides variable control over a Dressure ranee i p - - . propnace to the system of pump, spray guns. and nuwn- d. The OPERATIOX. CONSIDERATION FOR SELEC.

TION. and PRECAUTIONS for a back pressure regulator ue dmuU to thav for a fluid p m r w regulator.

II GLOSSARY Agitator: A device for stining the material in the con- Wner to keep the paint from settling out. It may bo powered by hand, alr. or eleckic motor. BJC Rsuure Valvr w Regulator: A device used to malntain pressure In a pump circulating system. It Is located downstream of the spray guns.

Bonom Outla Renun Tank: A pressure tank which stands on legs and has a bottom outlet. Used for materids that are heavy in viiscosity. O l o r Bme: A metal base wlth casters used to -port pressure tanks. Circulating Connection t“Y” Conneexion): Fits to the spray gun and allows material to circulate past the spray gun for retum to the material container. Circulating Wmm: A system for delivering material to the aevenl spray stations and allom retum of unused and excess material to the material container. Disposable plastic Liner: A plastic bag for lining the inside of a cup or pressure tank when containins material. It may be dispacd of when no longer needed. ‘This item saves dean-up time. D.O.T.P. DI Octyl Terephthalate: An inert plasticizer used to keep pumps wet. especially when they are handling the m m p e n t mate& of a multicomponent (PILI- rsl) &lish or alting pmdua. Double Air Outlet: A pipe fltting w d on the outlet side of a pressure tank air regulator to supply air to two spray pm simultaneously. Double Air Regulator for Pres” Tmk Control: Two m g ~ h t o ~ mounted in tdndem. One regulator controls .it pmrure to p r r u u ~ tank and llro feeds main-line, unregulated, u r to a second regulator. The second regulator controls air pmrure to spny gun. This type of control is often wed by painting contnctors. Double Fluid Outlet: A pipe fltting used on a preisure tank fluid outlet to supply fluid to two spny guns rimultdneously. Edge TYP Filter: An in-line fllter compaed of a series of identical plates stacked together. Each piate has three leaves similar to a Meaf clover. The plates are so stacked as to allow fluid nuterial to enter through the center of the stack and to leave through the periphery. The maxi. mum partide size the Nter will pau b determined by the thickness of the plates.

Fluid Regulator: A device installed in a pipe line for variable control of fluid pressure.

Fluid Strainer: A Nter device installed in a pipe line to remove oversize putides. Fluid Sminer Funnel for Pnnure Tanks: A funnel with a replaceable strainer m e n and offset neck to permit filling pressure tank without having to remove the tank herd assembly.

Follown Plan: A met.l plate whieh rides on the surface of material in a prtbnue c o n h e r to prevent the incoming pressurized air from frothing, cavitating. or otherwise agitating the nuteriai. Foot Valw. QNck Valve. M Ball old Valw: A nlve located at the base of a reciprocating power pump which allows fluid to flow to one direction only. G u r Pump’ A pump in which material is forced into the Q h pressure side of a system by the r t i o n of rotating, meshing, gem.

Gravity Buckn: A container with a fluid outlet on the bottom in which material is red to the spray gun by plvity. Head Gasket: A leather or synthetic lubber gasket used to seal the cover of a p m u n tank Inner Container (Liner): A container whlch is fltted into a pressure tank to expdite the chanfing of coioa md dean-up. Material: The liquid pmduct being sprayed onto a surface by the spray gun in a coating or painting operation. Mixing TMk: A container ured for mizing luge qumti- ties of materid. UwYy it has a bottom outlet for dnwing off s d l quantities of materid u required. Pinon Body Valw: A check valve loated in the fluid piston of a recipmating pump. It dlows fluid in the pump fluid cylinder to flow in one direction only, I” the intake chmber to the pressure dkehuge chamber. Piston Pump: A pump udng a cylinder and piston to force materid into the high pmsure ride of a system. Plunpr Pump OT Displ8ammt Pump: A mdprocatiag

pump which dirplam a volume of fluid qrul to the volume of the piunger. Rntun Cup of Prerrun Tank: A rsaled contliner in which air pressure is w d to force materid to the spray w. B I G : Pounds per s q m inch gauge. The prerture in a system as indicated by 1 dial gauge. Such a gauge indi- ~ t e i “zero” when the WStem is open to the atmosphere. Ratio of I Pump: The eNective area of the air motor piston over the effective area Of the fluid piston ( s n section I-Plc). l l w pump ntio number also defines tbe sailing pressure of the pump. For exampie: a K I : ~ ratio pump operating at 100 psie pressure will stdl at 1000 psig fluid pressure. Siphon Cup: I b e container for holding material when siphon spraying (usually 1/4 OL to 1 qt. In capacity). h n d Pip.: A small dimitter tank mounted with a fluid pump. ?he tank has 0 bottom inlet to allow fluid to enter and be pumped into the circulating system.

Sbdi-Grip Cup (Remote CUP): A pmznve container of one or two quart capacity connected to the spray gun by horer. T.C.P. Tricnryl Phospham: An inert synthetic lubricant used to keep pumps wet during shut-dom periods.

TaII-Talr Filter: A stnine1 with m indicator whlhich dt. plays i k “dirt-load” condition. Turbine Elrctric Pump: A Ugh volume rotmy pump used in me drculrting Systems. The hubine blades u mrny rrmll individually endored propellen mounted on one stuft.

89

Plural Component Spray Systems

I. GENERAL DESCRIPTION The spraying of plural component materials can be compared, in many ways, with the apraying of a single component fluid such as paint. Plural componants can be sprayed by either compressed air or hydraulic (airless or air-assisted airless) atomization. The main difference is in the purpose for spraying. Usually a single component material is sprayed for the purpose of dec- orating and/or protecting the product. This same reason is also the purpose for spraying some plural component materials. Other plural component materials. however, are sprayed so as to build and become the very "nruc- lure" of the product. An example of this is fiberglass reinforced polyester. Here, the product begins with the spraying of the external "final" finish into the mold. This is followed by the "spray-up" of subsequent layers, thus developing the substrate structure of the product. Each component of a plural component system remains l iquid until, i n proper proportion. two or more are combined during the spray process. Thus mixed and catalyzed. e chemical reaction lakes place causing the liquid to release heat and solidify, in a prowss called "thermosetting." The application equipment basically m u n meter two or more components accurately end deliver them separately to a mixing area or chamber. imparl enough energ,y to "blend" or mix thoroughly, and atomize it or causa it to flow as directed. It i s either sprayed directly, when atomized, into a mold to form a product, or on another substrate to become an integral part of it. "Flowed ma16 rials are not etomized. but when mixed are dispensed into cavities, containers or molds. They are usad to fill voids, "pot" components in assemblies, veal joints or duplicate the contours in molds or dies.

The equipment required to dispense the plural components is basically modified or similar lo standard spray equipment. A spray gun with two or more heeds or fluid inlets and supplied with material from two or more fluid sections jointly driven by one power source (electric air or hydraulic motor) standard type hoses and controls com- prise the basic system. TO consider equipment. one must fin1 be familiar with the materials being used. The bat source of this information is the material supplier who, in many cases. is the formulator. The supplier should provide you with the following information: 1. The most suitable type of material and 18 application or

end use.

2. The viscosity of each component at appropriate temper.

3. The materid component ntio. (By volume and/or weight) 4. The allowable tolerance in ratio and mixing. 5. The allowable temperature range of the material (when

6. The storaga or "shelf4~fe" of the material. 7. The storage requirements. 8. The flushing solvent required. 9. Can the component's viscosity be lowered with heat?

10. Handling considerations with regard to toxicity.

A'llst of some types of p l d component materials (usually referred to as "systems") that u e spnyed or poured indude polyesten, polyurethanes. adhesives. coatings. and epoxies. These materials may be mixed in varying ratios 8nd viscosities. When considering the equipment requifed. one must look at each "family" or dry of material; what they u e chemically, and how they ue to be handled.

atura.

It should or should not be used),

11. POLYESTER RESINS or F.R.P. (Fiber

Probably the most common Wpe plural component is polymer resin. (Ohm. this material is incorrectly referred to as "fibwglass"1. The polyester rqin bonds t h e lightweight. mong. flexible glass fibers into I stiff matrix to gain the physical properlies of both " r i a l s .

Polyester resin is a "1OO.A s o l i d (no evaporative solvents) liquid chemical that cures by fusing into a thermosetting mass through the introduction of a catalyst (usual. ly M.E.K. peroxide or Benzoyl Peroxide). In other words, when the polyester is completely cured (hardl. there will be no appreciable lots of weight from its liquid state.

Polyester resins are generally classified as either "gel- coats" (which are pigmented polyesters) or reinforcing resins (structural resins or "lay-up" resins). Gel-coats usually are used as the f irn (or color) coat in a product (comparable to the painted finish on a car or refrigeratorl. There are also polyester gelcoals which are used in the same manner as paint to offer protection against corrosion, and exhibit beauty or color. The "lay-up" resins are used with glass fibers or other fibers (such as cloth or mat) to produce slructures called laminates. They range in color from amber l o clear and are rarely pigmented. They are sprayed over the gelcoet and (the resinsl fuse themselves tothe fibers forming a matrix. The compo. nents then become a monolithic ("seamless") structure.

Reinforced Plastic)

90

Common glass, I i s W m l l y known. is a vrry britt10 sub stance which will b ruk or hatter when deflrcted or im- puted. This is beauso the large rurfico am with itJ nunv 'tlw reduces its tensile strength. In fibrwr form, the db c r e w size and surface area sharply reduce Ram. and the flexible plats fiber approaches its theoretical phmical strength. Tensile strength of the fiber is the prime factor of rn in~glas construction.

In a composite of glass fibers and polyester resins, each is important, in its awn way. The polyester resin in its liquid state is plastic and adhesive. This material holds the glass fibers without damaging or reacting with them, yet bonds the fibers so they cannot migrate or pull out This type of composite also is able to distribute the mess evenly, as well as contain any individual fibers that might break.

The combination of polyester resins and glass fibers are good structural materiels end offar the fabricator a number of advantages. Practically any shape article that can be de-molded is possible; since the polyester is liquid, it wi l l flow and readily surround or capture any fibers of fillers. The desirable property of remaining in a liquid state et room temperatures and solidifying only when a Catalyst is added simplifies the type of equipment required to work with it.

The temperature and mass of polyesters-have a tremendous bearing on the cure cycle of the resin. Usual- ly. the cure cycle is in the area of 15 to 45 minutes, depending upon production rates and product design, and is controlled by the amount of catelyst introduced into the system. Catalyst is utilized to overcome an inhibitor which prevents premature polymerization of the resin. The amount of catalyst used usually varies from 1/4 to 4%. based on weight or volume.

cold rubrtnto. will ddav the cur0 time cycle 4 to 10 timn tho stated timo. If you do not uhiwo a proper cure n the time yw gp ly the rar in inp coltinpr. the glass fiben will pmRrJte the prwious Coating and possibly cause s u r f ~ e flaws. ShrinkrOcafdOr wrinkles m a y also be evident. Thee are caused by nyrme etching of the uncured ra in on the glass fiber. High humidity will also inhibit good curinp, LT water and polyester are incompatible.

111. TYPES OF EOUIPMENT The equipment required to apply Polyester resins can be IS

simple as a paint brush or as complex as an automatic unit programmed to automafieally select. meter and mix the right amounts of m8terial as required. However. the most common tvws of equipment used are outlined in the illus. trations that follow.

1. Premixed catalyst and resin (gelsoat or lay-up resin) applied by brush. Ideal for samples or hobby: no large equipment investment.

2. Premixed catalyst and resin sprayed with any conventional spray equipment.

3. Catalyst type mixing equipment: a. Side catelyst injector system. Mixes the compo-

nents externally in front of the spray gun. The catalyst may be extended. or diluted, with an evaporative chemical such as ethyl acetate. Resin and catalyst are supplied to the spray gun with standard type fluid handling systems. such as pressure tanks or pumps. The equipment used on the catalyst side must bo constructed of corrmion resistant materials. See block diagram below:

(continued below)

AtomWng Alr Uno

ILLUSTRATION NO. 1 SIDE INJECTOR

Yay b. u u d with a compnaud air or rlr-ms8lstod M o s s aptem.

R =Resin (polyester) P = Promotoar (coban Naplhanale) C -Catalyst fMEK Peroxide or Dlchlom k o y l Pemxde)

Depending on formulation andlor application, the rains may hwe another chemical called a "promoter" or acceler. ator added. This chemical's lusually cobalt napthenate) purpose is to rapidly decompose the MEK Peroxide catalyst to effect polymerization of the rain. It i s important to remember that when the supplier stat= that the material will cure in 20 to 25 minutes 8 72 degrees F. at 8 thickness of 15 mils. changing either the thickness or the temperature in either direction will effect the cure cycle. A change of Only a few degreer in temperature can considerably change the length of cure time. The cure cycle is accomplished chemically by l h e generation of internal. or exothermic. heat. For example, too thin a film. or a film applied 10 a

The advantages are separate fluids, external mixing, easy cleaning and simple design and maintenance. The limitations are imperfect mix of catalyst to resin, easily plugged small catalyst side nozzle orifice, and dilution of Catalyst to reduce the error in pressure dispensing.

b. Catalyzed air injection system. A catalyzer Ismall pressure vessel with wly accurate rotometer) in- jects a measured quantity of catalyst (normally 60% strength) into the atomizing air supply of the spray gun. Resin is supplied to the spray gun with standard material handling equipment. During the atomization of the resin, the catalyst is mixed into the material to trigger the cure cycle.

'

91

ILLUSTRATION NO. 2 EXTERNAL MIX, AIR ATOMIZING SYSTEM

The advantages are: better mix, no small catalyst nozzle to plug, no dilution of catalyst by user, and spray gun can be equipped with either external or internal mix nozzles. The limitations are: catalyzer flow must be calibrated, special air hose and fittings required, and only limited quantities of material may be catalyzed at one time.

c. ."Split-Batch" or double nozzle spray gun system. Two individual quantities of equal volume or resin are premixed as follows: one quantity has enough catalyst added to effect a curs for both quantities, but just enough that a total cure may take many hours or days, as long as it is not mixed with the second quantity. The second quantity has a promoter or accelerator added. The two quantities, in equal volumes, are delivered separately to a spray gun and are atomized in such a way that the two materials are intimately intermixed; the intermix. ing may occur intemally or externally. The promoter rapidly decomposes the catalyst and a cure takes place a short time later.

prpduct. With "spray-up': a fiberglass "chopper" is used and by feeding fiberglass strand (or "rov- ing" as it is called) thru this device. the glass fibers are broken, injected into. and deposited. along with the resin spray, to fabricate a laminate.

IV. URETHANEjPOLYURETHANE FOAM GENERAL DESCRIPTION

Rigid urethane foam k i n inflexible cellular plastic formed by the reaction of two liquid chemicals. a polyol and I Polyiscqnate. in the presence of g8s producing blowing agent. It is composed of many t h y c l d clflr. e r h con. taining the tripped gaseous blowing agent Inormally a fluorocarbon such LT R.11 or R-12). The gas contained in the calls not only sham the cells during formation, but also contributes special properties. such as insulating cap ibilitiM-tO the foam structure.

(continued below1

chemical act!m

The advantages are: large volumes of material can be dispensed at one time with adequate mix: no small catalyst nozzle to plug. and no calibration of equipment is required. The limitations are: pre- mixing and precatalyzing of the materials must be done by the user; the catalyzed side of the system must be cleaned before the material cures, and a11 Catalyzed material must be used or removed during its limited "pot-life".

For hand lay-ups. precut sections of fiberglass cloth or "mat" of the proper weight and weave can be impregnated with polyester resin to form 6

ILLUSTRATION NO. 3 SPLITBATCHORDOUBLE NOZZLE SPRAY GUN SYSTEM

MinuI Imarmlxlng only shown. U u s on1 gun wlth two ilrlasr heads.

Physically. the foam is 1) permanent dispersion of a gas in a closed rigid plastic Cell. As such. both the gas and the plastic cell structure contribute importantly to the foam's physical properties The cellular structure gives it i ts exceptional strength for low weight. Closed cell struc ture contributes to the strength and also seals the foam against panetration by liquids or other p e s .

Chemically. rigid urethane foam is not a single material but a whole ctass or "family" of rigid cellular plastics bared on the urethane polymer. The control of the formulation to

achiwe the ri*t form for a spacial application b *ay come @ex and raquires great tahniul cMI)mIIce. It is for t h i s "on that obtaining spacific form ProPortia for special application and cost factors, the usN should conNntly be referred to his raw material supplier. Than is 1~ me that h a greater knowledge or experience than the pmon whore "stock.in.trade" is urethane foams. He may even formulate a system just for your particular application. Rigid urethane foams can be formulated in a wide range of densities.

Other types of urethane foams are classified as m i 4 g i d or as flexible. Flexible foams are produced by resting 8 polyisocynate and a polyhydroxyl material under carefully controlled conditions. Other ~semial ingredients include a blowing agent and surfactants to control cell structure and a catalyst to control speed of reaction. Depending upon specific application requirements. formulations may also include additional materials such as flame retardants. fillers, extenders, bacteriostats, pigments. and the like. Also. these foams can be formulated in quite a wide degree of flexibility. The physical properties are that the cell rtrunure is broken and open, giving the foam its flexibility. Semi. rigid foams are produced by merely adding more functional resins to conventional flexible foam formulations. The ~hvsical properties are !hat some of the cells are broken and the blowing agent has dispersed while other cells still contain the qar. The unbroken cells, or closed cells, give the foam its semihgid structure.

Flexible and semi-rigid foams are normally produced by the reaction of many components together at one time on a "slab4ne". Portable equipment usirq a 1:l ratio is mailable. however, the need for such equipment is limited. The Cost of formulating a 1:l ratio, flexible or semi-rigid foam system is s t i l l quite hi@.

TYPES OF EOUIPMENT The first basic urethane equipment system were'designtd for flexible foam "slab" lines, pines often being4 ft. wide by 2 11. high by 15 ft. long before slicing, 8nd most of the earlier equipment for rigid foams was an outgrowth of these flexible foam machines. Today, many users of rigid urc thane chemicals ar t s t i l l using modifications of this type of equipment.

When spray foam syrtems were fir5t introduced in the'late 1950s. most of the equipment was either toocomplicated or too poorly designed to be of much practical use. The equipment was much too difficult for the operator to understand or keep continuously operating, and the simple. pocrlymade equipment did not produce an acceptable finished product.

The early 1960's produced somewhat better aquipment as the equipmenl manufacturers began to learn more about the chemistry of urethanes. and were thus able to design around and to eliminate some of the maintenance and plugup problems.

The basic equipment which evolved was designed around the positive displacement reciprocating pump. This type of pump i s widely used to pump standard single component materials in the coating industry today.

The advantage of using a positive displacement pump is that a given quantity of material isdelivered at everv stroke of the pump.

In simple formulating equipmsnt. two or mom fluid see- tionr are Connected directly to a single power source which drives the fluid sectionr simultaneously. By varying the length of stroka or diameter of one of the fluid sections, as compered to the other fluid section, the ratio (or quantity) of meterial delivered will change. Controlling the stroke travel of the positive displacement plunger would also have an effect on the total delivery of that particular fluid section. With Ihe proper selection of fluid section and with the stroke travel determined, tha materials can be accurately metered to be mixed in infinitely variable ratios from 1 :1 to 18:l. all on one machine. Since the volume is determined only by piston and cylinder diameter and length, wear of parts such as in e gear pump, is not a factor. The repeaiability of a piston pump is constant.

ChemicJl manufacturers have also helped in the simplifi. cation of the equipment by formulating their materials t o be mixed in a 1:l ratio, 8long with some tolerance in the metering accuracy.

The two lor more),fluid KCtions now measure a given quantity of material with each stroke and forci or "pump" this material to the spray gun. The gun is designed so that the components, when brought together, will be mixed and dispensed. The mixing is accomplished either by baffles. surface tumbling (such as in 8 helix mixer), high pressure impingement of one ra in component upon the other thru diametrically opposed orifice, or mechanical mixing by the use of an impeller. The dispensing of the formulated materials will be either by froth. $pray (air or "airless") or poured. depending on the type of spray gun or components being used. One basic formulator is a11 that will be required: howcver. the spray gun (or dispensins headl may change depending on the method of dispensing or atomization being bred.

When materials ere mixed internally in the spray gun, any material remaining in the mixing chamber must be purged thoroughly before the mterials have time to react ("set up"). Since moot foam systems start to harden within a few seconds, purging must be done immediately upon completion of spraying. The purging is accomplished in the gun by using solvent only, a mechanical plunger, or a solventlair mixture.

The advent of m e r equipment for foam. including some changes in chemical formulations. has led to the develop men1 of very simple two component systems. These svr. tms have lightened the weight of the spray p n by r c quiring as few as only three hoses; an insulated pair of fluid hoses and one for the solvent purge system. The pumping system. or formulator, i s designed to vary the ratio of the materials pumped from 1:l to 18:l. Inter. changeable fluid sections with different capacities are often used to vary the delivery rates.

Heater5 are provided to reduce the viscosity. aid in the mixing of the components. create uniform cell structure and perhaps produce foam with the best physical proper. tie. as well as greatly enhancing the surface appearance of the foam. The heated airless system produces the best surface uniformity or finish, as well as being the easiest of 811 sysyftems to operate.

Other two-component resin materials may also be handled with the same basic equipment design. Materials that can be best handled with these systems have a mix ratio renge of 1:l l o 18:l and must be under 100 CPS in viscosity. Heating can reduce the viscosity of the material which then can be handled with the same basic equipment. A particular system must be checked out with the raw materials supplier before heating. Most suppliers heve viscosity temperature grephs readily available.

a. I f qu ipmmt is air operated. Is sufficient air available:

e. Portability. i f required. sire of unit or weight 7 f. Fixed or vfiable ratios ? g. Fixed or variable fluid deliveries 7 h. Is equipment capable of handling other types of plural

i. I f material i s to be heated. can heaters be adapted to

not only in P.S.I. but in C.F.M. 1

components ?

the equipment. ?

w Matar Y I

Heatar Wt Tracing lap. f

Componmt Component

v. EQUIPMENT SELECTION

General knowledge of a field of endeavor is required before knowledgeable queriesan be aked. The following is a list of considerations required in selecting plural comwnent spray ‘equipment. 1. What exactly is the job at hand? 2. What type of materials are available KO do the job? 3. Who is the raw material supplier? 4. What are the end requirements or specifications? 5. What type of available equipment i s required for your

particular application? With the type of equipment a t a b lished. the following must be known: Material: a. Viscosity of each component at a specified t e m m

ature. b. Will material Bccept heat? e. Specific gravity. d. Ratio of resin system. e. Reaction time once mixed:

CONSIDERATtONS

1. Cream time. 2. Rise time. 3. Tack.free time. 4. Cure time final.

1. Pot life once mixed. g. Shelf life. h. Mixirig ratio of materials. i. Number oi components to be mixed at one time. i. Accuracy of mixing required or tolerances. k. Toxicity or corrosive nature of materials. I. Curing time of material.

m.Diluting or thinning of material end. i f required.

Equipment: a. Air or airlm atomization. spray. pour or froth. b. Required output of material. e. Required operating pressures.

what percent.

4l

ILLUSTRATION NO. 4

j. Service or instruction manuals furnished. k. I s technical advice available on equipment iirequired?

I. Maintenance requirements of equipment. m. Amount of training required to opeme equipment. n. Spacial instruction relating to operation of equipment.

If XI. by whom - factory or loul representative.

VI. GENERAL MAINTENANCE OF PLURAL

Always refer to the manufacturer’s literature for prescribed maintenance instruction. Especially, pay close attention IO preventive maintenance ssction and notes. The basic main. tenance considerations required for maintenance of plural component equipment are listed:

1. Pmonnel who are operating the equipment must be fully trained in the idiosyncrasies of the equipment.

2. Follow the raw material supplier’s instruction to the letter, especially regarding the proper handling and stor. age of the formulations supplied by the material manu facturer.

3. Whenwer the equipment is used or stored for a period of time, it must be cleaned thoroughly (see shut-down procedures in manual: they may differ from an ”over. night” VI “weekend” period).

4. The system must be kept “wet” (filled with liquid) at all times to prevent m y temaining materials from set. ing up when exposed to the atmosphere.

5. Use a solvent that is compatible with the resin mater. ials being used. Incompatible solvents remaining in the hoses or pasraga may cause partial cure or gel if not removed.

6. The equipment must not be left open to the atmm phere for any length of time LI miny materials (am ially isocyanates1 react to moisture in the atmosphere. A procatalyzed material that h r s been used in the system must be removed prior to its curing rime. Do not overlook hoses or spray gun fluid passages for cleanliness.

COMPONENT EQUIPMENT

94

1.

8.

9.

to.

Extreme cleanliness and good housekeeping we a must. If equipment has filters, clean periodically according to e check list or schedule. Do not substitute standard hardware items without careful regard as to construction and pressure ratings. Do not interchange hoses. fittings, pumps, tanks. or rollers, otc. from one component side to another (keep "A" with "A").

Good housekeeping and proper maintenance of any type of plural componmt equipment is a MUST in keeping 8 swtm in good working order. Failure to maintain equip ment properly may lead to problems requiring extensive m i c e work which can be costly. The greatest limitation to this type of equipment is the customer's lack of responsibility towards the equipment, especially in not deaning and maintaining the equipment. Check service manuals, or with the equipment manufacturer for his maintenance r r commendations. The peneral maintenance notes listed here will apply for any plural component equipment system rwrdless of the type of material used or the manufacturer.

VI]. INDUSTRIES UTILIZING PLURAL COMPONENT EQUIPMENT

~~~~

Commercial applications of plural companent equipment are too numerous to compile a complete list and new ones are constantly being added. The materials that are used in these systems can be "tailored" to meet virtually a11 type Of conditions encountered. Some of the uses or products of plural component equipment and materials arc: 1. FOAMS-For insulation. void filling. flotation. curhion-

ing, and packaging. 2. LATICES (LATEX) - Similar to fully flexible form

which is used in furniture, as sound deadenm, void filling, laminations in combination with fabrics.

3. POn lNG COMPOUNDS - For electrical components, position retention heat sinks. surface repair.

4. MOLDING - Reproduction of images. model making. mass production of art forms, casting. temporary tooling.

5. BARRIER FILMS - Moisture, gas. sunlight, liquid tarpaulins. weather protection. "cocooning" of p m ducts for storage, %paration membranes, shdten.

6. LAMINATIONS - Combinations of materials to de velop certain physical properties. sheathing, v e n m , fumiture tom.

7. CORROSION PROTECTION - Lining of chemical pro. cerring and storage tanks, protection to the exterior of buildings and structures. marine salt resistance.

8. BUILDING MATERIALS - Insulation. structural w p port, roofing, curtain wall, sound.deadening, wood imitations, interior decoration, tlooring. marine craft, sealants. glazing, joint bonding.

Major industries using plural component type of equip ment and materials and their UM include: 1. Aircraft or aerospace require sealants for sealing integral

components. potting assemblies. adhesives. encapsulat. ing. metal honeycomb. radar domes. leading edger and structures. heat shielding.

2. Marine Industries - reinforced plastic construction in hulls and decks. Deck coatings and joint caulking, con struction of interior items, floatation.

3. Construction. joint seals in curtain walls. insulated windows, road or runway expansion joints. hVo.com.

ponmt mmbraneJ between concrm Iaym or asphalt in hiphway bridge structure8 to prevent the imitable effects of salt. chloride, water, freeze and thaw cycle conditions. bondinp agents for drywall construction.

4. Electronics: Di-electrical insulation or barriers. create soft rubber4ke materials to a n x shock rbsorbcn, porting and heat sinks.

5. Industrial applications - Plural component equipment and materials can find their way into virtually any industry. Every day new and different applications are tried or become mailable for use. The only limitations to this equipment is the people who employ it a d their ingenuity to find new a d better ways to improve their product.

VIII. GLOSSARY OFTERMS CATALYST-A substance that initiates a chemical reaction m d enables it to proceed under milder conditions than otherwi$e pouible. CATALYZER-A device for injecting a measured quantity Of utalym into the atomizing air supply. ELASTOMER-Any of various elastic substances resembling Nbber. EPOXY-A molecular.containing oxyQen atom attached to two different atoms already united in some other way. EPOXY RESIN-A flexible. usually thermosetting. resin made by polymerization of an epoxide and used chiefly in coatings and adheaives. --A compound formed by the reaction between an acid and an alcohol or phenol with the elimination of water. K)RMULATOR-A machine designed to meter and pump materials in 8 prescribed or definite form or method. MHIBITOR-A substance that s l m d m a chemical reaction. ISOCYANATE-A salt or ester of isomeric cyanic acid HNCO Used especially in plastics and adhesives. POLYESTER-A complex ester formed by polymerization or amdensation of an acid and alcohol. POLYMER-A chemical compound or mixture formed by polymerization and consisting essentially of repeating struc- tuml units. \

WLVMERIZATION-A chemical reaction in which two or more small molecules combim to form larger molecules. POLYURETHANE-Any of various polymers that contain NHCOO linkage and are used especially in flexible semirigid a i d foams. elanomerr. and resins. PROPORTIONING--The relation of one pan to another or to thc whole with respect to magnitude. quantity or degree. or to mate the pa* harmonious or symmetrical. RATIO-The relationship in quantity. amount or size between two or more things or the indicated quotient of two mathemat. iul expressions. RESINS-Any of various solid or semi-solid amorphous fusible flammable natural organic substances that are usually transpar. ant or translucent and yellowish to brown in,coior. are formed especially in plant secretions. are soluble in ether and other organic solvents but not in water and are electrical non- conductors. SURFACTANT-Additive lotten a siliconel to control size. height of rise and closed cell prcentages. URETnANE-The urethane polymer involves the reaction of a polyisocyanate with compounds containing reactive hydro gens. Typical hydrogen bearing materials used include polyethers. polyesters. castor oil. simple glycols. amines. car. boxylic acids. and water. VISCOSITY-A material's resistance to flow.

http://hVo.com

Methods of Application ~

Illustrated here ere the baric spray methods used for plural component application:

[I] Premixed Catalyst and Resin (Internal Mixing)

For small jobs which can be completed within the pot-life of the mix. Normally 1-quart cup to 10-gallon pressure tank. Suitable for frequent color change. May also be used with catalyst injected into air.

Resin with Promoter, Resin with Catalyst (External Mixing)

For 2- to 55.gallon applications. Recommended where one color is used. The two resins are separate until mixed enernally in the spray pattern of the nozzles. May use pressure tanks or fluid pumps.

For 2- to 55-gallon applications. Recommended where one color is used. Catalyst is injected into spray pattern where it mixes with resin. May be used with pressure tanks or fluid pumps.

Catalyst Injection (External Mixing)

Resin with Promoter, Resin with Catalyst (Internal Mixing)

For 5- to 55-gallon applications. Recommended where one color is used. Materials are mixed internally. May be used with pressure tanks or fluid pumps.

Chopper for Fiberglass Layup Can be mounted on any 2-component spray gun. Chopped fiberglass is fed eaernally into spray pattern. Used to give rigidity to layup resins in products such as boat hulls, car bodies, storage tanks. etC.

Externally Catalyzed Resin May be applied by conventional air spray gun or by air-assisted airless spray gun.

PLURAL COMPONENT SPRAYING . FOR THE FURNITURE INDUSTRY

0y Jury R Hund Blnks Manuhcturing Company

Furntturefintshers havelongstrked for mat perfectltnishthat willnotonlypro- tea. but aecoraletheir productsaswel~. Thecoattngmatertaisthatrost manufac- turersusetway may bethesamemate nalsyou havecometotrust overthe years. For wood. nttrwelluiose lacquer has been Ihenumberonechotce. The benelits oerived from rnts material have made it number one. However. there are newer coatings oemg intrwuced to the markel Diacethatmanyfeelmllgtve nitrocellu. lose lacauera runlor itsmoney. Manulac- lurers are alreaoy ustng newer plural component finishes.

Recent concem overthe environment. Coupled withthe necessity01 thelintshto provide us wtm superior hardness. gloss rerentton. ullra-nolei protection. durability. ana nlgn disttnclion of image. have given the fumirure industry new challenges to face. One way IO provlde us with these benelits w w l d betocmstder using plural component coatings Such as catalyzed lacauers. polyurethane and pdyesten

Toaayk popular 'wet look conststs of specally formulated pluralcompooent polyesters. and some polyurelhanes.

Regardless of the application lechntque usea. plural component coatings must be handled with extremecareandaccuracy underthr64separateoperations in the 101- lowingnroor. mier mix, r l i s ~ n c p Per. forming these threeoperattons correctly is thekey lo successfui plural component lintshtng. Allhougn youcan dispense these coatingsundera wide arrayolapplication processes.thisarticle willlimit ttsdiscus- stontosprayfinishing with pluralcom- m e n t materials.

Regardlessofthecoating us-. ortne specialequipmentusedtoapp~y 11. there is a fundamental ruiethat must be closely adhered to. This is relerred to as the M-0-EPnnciple. Each lener represents an imporlanflinkto asuccessful linishtng operation m e w represents me materia;. m e V representsme spray operator. and the 'E' represents the equipment supplier. C m w r a m mustexist among

Puiseless Fluid Flow ADililyto Manole Soecial Fluids

Max Fluid Delivery

Rata 4s Ftela Alleraale

Tywsol Alomizatlon

Easy IO Operate Recommenaeo for Picductton Spraying Average Cost

Eauipment Lite

Pwer Source

Adnntsger and limltationr

Mechanical Gear Ralio Pumps

YeS

No Not recommended for htghly

abrzstveormin materials 29 oz lmin

(1 1 ratio6 14%oz of ea Comp )

Yes

Compressed Ari

Yes.

Not toexceed29oz.Imin (a 1.1 ralio

54-6.000 Good lormostcoarings

%Special Flutds Seciion

Compressed Air

Y.-L

Hydraultc/Air Operated Plural Component Pumps

No

Yes

UP IO 5 gpm

Yes On Some Higher

Priced Units Compressed Atr

Airless Air Assisted Airless

Yes

Yes

$9-12.000

Very Goad

Compressed Air or

Hydraulics . ..

all threegroupsinorderto haveasuc. CeSSIul linishing operation.

When using plural componen! materiais and equipmen:. excellent communicattons mustexistamongrhesetnree parttes., Failure ~odosowith]ustonearea may ultimately ieaa to costiy down time. re- *:%. or destroyed spray rquipmeni. Management and operatortratning IS oeb ntlelyamust whenanempttngtospray Plural component coatings for the firs: m e . Special emphasismust always De placed on proper matntenance of me sprayequipment. Belore you purchase any PluralCOmpMentspraying equip ment. make your equipment suppller provetoyouthathisequipmentw~~~ pro. ndeyar with theresunsmat you areex- pecting. Remember.yooarelustnot buy n g equipment but rather results of what Ihat equipmentmll dofor you.

LetSbeginbya%nWnngtm,olthe mt popular systms use0 today by lur- mture finishers. like ywrself to properly meter. mx and dispense piurai camp- ~coatings.hesewillbesystemsus- rgmechanicalgear rauopumpsvs. sys- !em ustng reciprccating pumps

Mechanical g a r tatlo systems

These systems incorporate air operatea POShedisPlaCement gearpumps to ac. wratelymeter thellowof thecataiysr aW resin tothe r"gcnamber.The operatorselectsineappropriategear ra- tdoofthecatalystand resinsupply per hs material suppliers instructions. These plm~smaybelte~OalteraDletoallowfo: amderangeof rattos. Ratiosfromtne Uylal1:l allthewayuploanexotic 14 1 raft0 can be obtatned by manually chang. ln~mgears (Srmtobereieaseo gear pan~sw i l l allow lorrattochanges mthou: manginggears.)F!mratescan& con. trolled separately by varylng me speea 0: ~a t r ro to r tha l stmultaneousty orives thesegear pumps Apulseess tlu~o liow dupto 29fluid ounces perminute rar 1:l ratlo) IS possible.Catalprand rem I N S 1 be force led to the gear pump un- derseparate flutd suoply l r m eilner ~ m p o i pressuremks.

Oncethecataiystana resin areaccu- ralelymetered. meymustbemtxea This lsoOne by aeltvermg bolh componenrs separatelytoamandoldwhtcn then lams bahmaterialsiogether Orcelotpeo !ne hvOcnmmnts qusttraveltnrough a hcsecontatntng astaticmlxer Theman,. e,

(see Fig. Y1)

.

PLURAL

(gear ratto) pump Don 1 worry abcui ma. tenal not beingadequalely mixed in the snort trave( between Ihe manifold and nozzieotthespraygun. thestaticmixer o t w v e d totnoro~ghlymixtomcompo- rents together several milltontimesover

Nowlhatlhecoatmghas been accu- ralelymetered and mixea it must bedis- pensed when usingamechanical gear rattopump.thiswouldbepertormedun. dernormal compressed air spraying practices

These units have been successfully usea ina wide rangeollumnureappiica- llOns especially 111 Sliidil custom l~rusnig shops Consult thecoinparisonchart tor lurlher information

Hydraulic andlor slr operated Pump systems (See Fig. 8.2) Hyoraultc anam airoperated plural component pumps incorporate pumps containing two(ormoreJlluid Sectonston- netted atrectly in lhne to a single power source The powersource whichmaybe hyaraulicalh, driven or an air operated pis- Ion anves the IIuhd seclions s i w l l a m s . ly BY varying fhemroktngdistanceorthe volume displacement of one of me fluid

seclion.the rattocfawnldyolmate~ats rrJl m e . Wmtlwprowrsektwd tlwHutd~ionandmMlhestroketra~l deIemned. mtoltodaykplufalcun. ponBMcostings wedbylhetumiture tn- dustwcan beproperiymetered and aetiv. eredlo our static mixing device. The lluid secfionsmay be submergeddirectly into thecoattgs orthey may have siphon hoses cwected to theif bottoms lor eas. iersiphcningfrommost containers. Flow rates with these pumps can exceed several gaflons per minute--more than enoughto~rateseveratgunsonatur- nilurepmduction line.

Themixing of these plural components isaccmplished by pumpingthelwoma. lernais seyaralelytome manilold ana static mixer as prevtouslydiscussed. When using high pressures (airless and air as. sisted airless) all fluid lines and mixing Chambersmusltefined with htghpres- surehoses. linings. etc.

As Prmslymentimed. the static mixermaybelocatedatthespraygunor althe Pump. depending upon the circumstances.The staticmixer is usually lo- 'catedatihespraygunwhentrequent color charging is done as well as when usng rwdcuring formulations. Thestarc mixer ww!d be siluated at Me pump to p w d e easier manewarability of the S P W Pun.

with menewpiura component pumps pmdescnbed. thedtspensingor spraying of plural component ccatmgs can now be accoinplisned under normal compressed air. airless. Orthe new air assisted airless spraying conditions

Aswithanyspraying.8ushing 01 ail fluidlinesdthecatalyzedmafertals must be accomplished with the appropriate sol. vent through all passageways when finished To assist us. a special solvent purge tank is a necessary additmnlo any plural component system

Although there areother plural comDo. mlpumpngandcatalyslmixing sys. 1EmSawallilbkthetthat have been outlined arethemst widely usedinthe lumiture induStrytOday Further informa. tion is available from yourequipmenr supplier.

Plura. Canwnent coating matertais have~naaedlounathemselvesapiace In the wwouormg tnoJs1ry. as weal as otner uutustnes Horrever they also present SDeCiai oiH!cultles 10 me untialneo opera. lonor users Regardiessot me piuia COmwneOl system you seiec: ai. muse melw mlxanoolspensemecoal.ng onlo Wrtumllun blhsystemsnaveme~r amantages MO limdalions Your c q u i p " w e r s n o u ~ o beaoie IO slwwouIkssanootners. oeaenoing

sections as m p a r e a totheother fluid -

Fig. #I

Mechanical Gear Ratio Pump System

mWurre.wmr"s

S t a t i c Mixer Assembly Located at Pump

Uunl

S t a t i c Mixer Assembly Located a t Spray Gun

....

Airless Spraying

WARNING-HIGH PRESSURE-WARNING UP TO 3000 POUNDS PER SQUARE INCH

DO NOT POINT SPRAY GUN AT ANY PART OF THE HUMAN BODY

FLUID UNDER HIGH PRESSURE CAN PENETRATE THE SKIN AND CAUSE SEVERE INTERNAL INJURY

IN CASE OF INJURY OBTAIN MEDICAL ATTENTION IMMEDIATELY BE SURE TO REPORT NATURE OF INJURY AND TYPE OF FLUID OR SOLVENT TO THE DOCTOR

Be sure you understand ALL of the irutnrdm thoroughly BEFORE operaung any part of M wieu C~UDIIIM~

CONSULT YOUR BINKS REPRESENTATWE TO CLEAR UP ANY ITEMS OF INSTRUCnON YOC DO qCrr

These innnrrions are designed as a guide for operators of Binh Airiesa EquipmenL Setup, operation, Md maintenance information b Listed to l id in w i n g the equipment in good, troubbhet cmdirim Trouble shooting chuts arc lined to J d in isolating nulIu"s that nuy occur in M &*ar pump or gun. Refer to the Rru Shm supplied with each component for speciec operotion and maintaunce inn-, w well as puu listings.

'AIRLESS SPRAYING Airkss spraying Is a method of spray applicrrion that d o e not diredy use compressed air to uomize the paint or other coating m0~eri.L Hydrruli p m r e b uud to uomize the nuid by pumping it u high p m (WO to lsoo psi) through a small oriace in the wmy nonlc. AS the nuid is released U thm high p w m , it b nplrucd into small droplets resulting in a very h e . or UanM spray. The nuid is discharged from a small nozzle o d c e u n r h a high wlocity that the material wan iueU sufficient momentum remains to urry the "fe ponicks to the surface. Since air is not used to atomhe the material, the term " A i r W is used to describe this method. Water is hydraulically atomized. for eumpk. using the h e spray " - z n t on a garden hose no&; however. it is accomplished with low pressure be- 01 th low viscosity of water. Paint and other coating "rials haw 8 higher viscosity; therefore they requirr higher p r e s u r a , requiring a pump.

m d

Alrprnsurr ia ~ U i r r d m l y to operate the air m o m which Povrrs WOFU fluid P- U a @en ntio depending on sue ofthe alr motor piston ud the effective area of the fluid pLM. E.unpL:A pump rued u 25:l. develops fluid prrwrr 25 fima the &-re applied to the air motor. For 1M) psi air prrssure, w)o p i fluid pressure muits.

rrCipmcEung airless fluid pump. A pump

HOW TO SELECT AN AIRLESS PUMP Type of materials to be spnyCQ size of job, volume of air d h b k nll are considerations which g m m the xkcuon of the pmieulnr airless pump rhpt is right for you and the muon for the wide w i e t y of pumps in our fine. When ackcting an airleu unit, answer thzsc questionr: 1. what type of material Is to be spnyed?

Determining the genenl ch.ncteristiu of the materials to be spnyed b an important step “I proper pump X*ctloh Low viscosity materials n r h u spins and &quem can be spnyed with small oridce nods (.DO7 to .NE). To obtain the flow of heavier viscosity materials, larger ofice nozzles and higher ratio pumps are rq&. Refer to the Airless Nozzle Flow Chart below and sckct a node range which is best suited for the material to be sprayed

In the pressure columns of the Airkss Nozzle Flow ch.n, Ovo nU of figures are shown: An ounce per minute delivery nte and a CFM figure. By dividing the ounce per minute figure into 128 (128 ounces per you un d e t e m n e how many nozzles of a pvticulpr size can be operated from a 1 CPM pump.

Adequate air supply for efllcient operation is dewmined by multiplying the number of nozzks to be wd by the CFM figure in the Airtws No& now Char~ulowuwr should be made for ulditiaul air opentcd .maroriea such u agiutom. ctc

2. How much material volume does the job rqulre?

3. How much air should bt avaikbk?

AIRLESS TIP SELEdtlON Tips are ackcted by theu midm size (Bo7 to .on Inches) .ndfanangk(IOto80dcgms).~pmper~lcet ion is determined by the fan width required for the spcci6c job and by the ondce size that will supply the ddred

the material. amount of liquid and a c c o m p l i proper amnkwbn Of

For light V~.UOS~~Y fluids. m a l k r orifice tips generally an desired For heavier viscosity fluids, larger ori6ce tips are prefIUrrd The quantity of fluid sprayed is determined by the size of the orfbce; the thickness is determined by the o d e and the fan angle. Note that two nozzle tips having the surne oritice but different spray angles, deposit the IPN mount of paint over a different area Note that orieces are not cirdar but are eliptieal in shape. The diameters referred to ue equivalent to a Circular diameter. A good d e b to determine the !Wesf fan angle and the smallest M c e that b procriepl for your rpeclfic Iluid and applica- tbn method. This indicates that a good selection of tips is required to meet all conditions. For (he majority of job conditions. only w Ups arc rctually needed. A large tip with a wide angle; ie. 92180, and a smaller tip with a narrow an@: Le. 91530. Thts type system will work and is practical If fluid viscosity and fluid pressure are intelligently used u controls.

. n.

HIGH PRESSURE CAN CAUSE SERIOUS INJURY IFEOUIPMENTIS INSTALLED OR USED INCORRECTLY -READ, UNDERSTAND. AND OBSERVE ALL WARNINGS AND INSTRUCTIONS IN THIS MANUAL

OPERATE EOUIPMENT ONLY AFTER ALL INSTRUCTIONS ARE CLEARLY UNDERSTOOD.

Injection Hazard 1. The Sprayer pumps coatings at high pressure

(2500 PS1/173 Bar). If you spray yourself or anyone else at close range, the stream of material can puncture the skin and cause great harm (possible amputation).

2. NEVER point the spray gun at yourself or anyone else. The tip guard provides some protection against injection injuries, but is mainly a warning device. NEVER remm the tip guard. Never point the spray gun at your hands. fingers, or body. AL- WAYS keep the spray gun trigger safety catch locked in the OFF position when not in use.

3. DO NOT aver the tip guard and attempt to "blow back" fluid. This is not an air sprayer.

4. If injury occurs, see your doctor immediately! DO NOT TREAT THIS AS A SIMPLE CUT. Inform your doctor specifically of what fluid was injected.

Avoid Static Sparking Static electricity charge builds up by high velocity liquid flowing through a hose during flushing, deaning, or spraying operations. Proper grounding of the airless system safely dissipates this charge. Ail high pressure airless systems must be grounded to avoid dangerous static sparking, explosion, or fire when spraying or flushing with flammable liquids.

Use Binks NO-WIRE conductive hose in all airless spraying operations. Be sure gun and hose have continuity. Check continuity weekly with ohmmeter. Overall (end to end) resistance of unpressurized hose must not exceed 29 megohm (max.) lor any coupled length or combination of hose lengths. Make sure the airless Pump is grounded. Never operate the unit when it is on a non-grounded plat-

form. Electric airless units are grounded through the grounding Prong on the plug. The electric cord or receptacle must be grounded. Do not alter or m m m grounding prong. When flushing or cleaning with a combustible solvent. always use an open metallic wntainer for receiving the waste solvent. Ground the solvent receptacle. Bond the spray gun to the W e container with a grounding win. Be sun there is good metal to met- ol m a . Ah& r e m spay tip when flushing the airless system. Operate the pump at the lowest possible preclsure.

Gonenl Wamlngr 1. NEVER leave a Pressurized sprayer unattended. 2. DO NOT use fluids, coatings. or chemicals that are not comparible with nylon hoses.

3. Periodically inspect all hose for leaks andlor abra- sions and tjghten all connections before use. DO NOT ATTEMPT TO REPAIR a defective hose. REPLACE it with another caductive hose.

4. Follow all warnings and precautjons of the coating and solvent manufacturers.

5. ALWAYS relieve Pressure in the system by turning by pass valve to BYPASS or triggering spray gun before disassembly of any cMlponent parts.

Replacement Parts The Airless Sprayer is designed to use authorized parts only. When using this pump with parts that do not comply with the minimum specifications and safety devices of Binks. the user assumes all risks and liabilities.

102

BASIC AIRLESS SYSTEMS Dead End System: Dewi end systems ue used for the majority of standard q d l t y tlnishing jobs. Y l e gun is crmneaed to the pump with a sin& hose. When the gun is spraymg. the pump delivers fluid under pressum 8d~wted by the air pmsure to the pump. When the gun is Mt

spraying, the fluid prruurr and .ir preWm UC balanced and the pump stops. The puplity and e c m y of the Bnish Is dependent upon operator Skill. fluid preplnuon and no& size. Dead end spray is usually employed with m-heated paint.

Air S u d v I 1.Gun . . .

: . .

2. Pump 3. Hose 4. Compressor. ekctric motor

or gar engine 6. Siphon tube 6. M a t e d supply

DEAD-END SYSTEM Used for the majority of standard quality spray Iinishing applications. Usually employed with non-heated methods.

Cuculaung System Cuculating systems are w d for h~gb qualit). the pump with one hose. and to a pressure regulwng valve W l t h anothn hose The pump pmvides pant under pressure conunuously The back pressure regubng valve provides a constant fluid pressure and volume for the gun when sprapng When mt spmytng. the co Iuwt pressure IS

A

atill .Milable os che pump is rec~culaung the pant. "he quality and economy of the &ush LT leu dependent upon the openmri skill or pant P~para t~on. nnd IS more d o r m because of mecha~~cal consutency of pressure and volume control. Clrculaung systems are usually used with he& pnrnt

producuon Bwhes. The gun IS connected to

, 1 I SUPPb

\ -Back-

I HOT CIRCULATING SYSTEM

h s h e s where pigment senling IS a pmbkm. RecLcvlwng systems are normally employed with hot =less

M% mi*: tu0 Producuon

AIRLESS-ELECTRIC POWERED and GASOLINE POWERED The basic components of an eka r i c dnvm plrless pump are the fluid seetron. gearbox, and ekctnc motor

On Enpin Gembox Gearbox

M o t u Clutch

h n S U f 8 bntml

fluid Section

5

Control

ORlRCL 600 P.S.I. lwo P.S.I. I 1600 ?.S.L 2oon P.S.I. zsw P.S.L

4. 01.- .5 dm 5, 01.- .Wdm 8. a- .8 h .an .w9 4.5 01.- .58 d m 5.7 ox.- .76 d m 6.8 01.- .87 d m a11 6.502.- .8 d m 8.5 ox.-1.1 dm 12. a- 2. d m

6.7 01.- 1.4dm 8.4 O1.- 1.8 d m

7 02.- 1.7 d m 10 01 - 2.7 d m

14. 02.- 2.9 dm 15 01- 3.8 d m

The chan below lists recommended tips.

.013 12. oz- .8 d m 16. ox.-1.1 d m 18. a- 3. d m

.015 13. 01.-1.1 h 10. or.-2.5 dm 24. 01.- 4. h

.016 14. 01.-1.3 d m 22 0&-2.9 d m 29. 01.- 4.8 d m

22. 01.- 4.5dm 2602.- 6.4dm +I. 02.- 6.7dm 3201.- 8. d m 34. 01.- 7. d m 3902.- 9.7dm

.ole

.021

~ ~~

12. a-1. h 19. 02.-25 d m 26. 01.- 4.2 d m 35. 02.- 7.4dm .401.-10. d m 14. 02.-12 d m 24. or.-3.5 cfm 32. 02.- 5.3 h 16. 02.- 8.5dm 56oz.-13. d m

.026

.031 .036

21. o2.-2.7 h 34. 02.- 6.7 d m 51. 02.-11. d m 6502.-16. d m 2tr. 02.-3.3 d m 48. 0%- 7.4 cfm 65. 01.-14. d m 8502.--21. d m 32. 0 2 . 4 2 dm 68. 0&-11. d m 95. 01.-20. d m 12601.-31. dm

,043 372

3;. 02.4. d m 61. 01.-10. d m 105. oz-22. dm icjor.--~6. ctm 72. oz .4 .5 d m 112. oz.-l8. d m 151. 01.-32. dm 1900~.--06. d m

OPERATING TECHNIQUE Opm air ~ p p l y to pump and i m u e au pnrure at pump until putem andlor material can be obruned at the m v m.

'Ihe proper SPEED allows a MI wet cou applleuron wuh each st&. Uthe d e d fthn thckclmcu cannot be obmned with a single stroke or p p u becaw of "w@ng", rtnn two or more c o w can be applied with a Ibh-off period between each,coaL The spray movement should be at a comfortable nu. If the spray gun movement is excessive in order to avoid flwding the work, then the fluid no& wiece is too large or the fluid pressure is too high. If the s t r d e speed is very slow in order to apply full wet coats. then the fluid oressure should be increased slightly

The gun should be held PERPENDICULAR d moved PARALLEL W the surface in order to obtain a unilom C d n g of mrterisl. Uneven Illm thickness and excessive offspny can be caused by ARCING the gun. When arcing, rhe heaviest deposit of paint occurs when the gun is perpendicular to

r~ ~~

the work in the center of the arc, &d lightest at the ends of the arc (see below right). Arcing is caused by wing only wrist or Ioream movement The wrist. elbow, and shoulder must aIl be wed. Once the best working distance (10 to 16 inches) is determined, the spray gun should be moved across the work at this optimum distance throughout the atrcke. Snm object shapes do not allow this practice, but it should be w d whenmr posdble.

or a larger tip is required.

RIGHT

P.rp.ndlculw Ardnp Gun at Angle

SPRAYING TECHNIQUES Proper LAPPING (the distance between nmkn) ir essential in Prodwins uniformity of 5im thickness. Thc

overlap should be the minimum required to give the degree of unifor" desired. The more uniform rhe lapping is mpintaineci,ihe more uniform he 5im fhjchc9wii1 be.

TRlGGERING the gun is and to prevmt excessive p h t buildup at the end of uch nmh.

to c m r v e material

'RECAUTIONARY NOTES 'he following precautions must be observed for personpl afety and for protection of equipment

8. Carefully handle the hose connections. joints. and seating surfaces on the spray gun to prevent damage to the sealing surfaces.

9. All airkss spray units must be grounded to preveni the possibility of €trees. electrical arcing, shocks. etc.

Keep air compresson as far as Ieasibk away from painting are& in order to k w n the possibility of compressor contamination and to aid in keeping the equipment clean. Operating with excess fluid p r e u u m does not improve the finish. but only shortens the life of the equipment and increases wear of the spray gun fluid tip. Never attempt to remove the hose or gun before rekasing rhe pressure Iron the outAL Never w standard hardware to modify the pump. Use high prrssure 5ning5 only. The special high pressure nylon braided h w supplied is standard equipment by Binks. This hose must not be 1 ninked. bent. or subjected to nbrasion. k d e r no circumstances should the spray gun be :arelessly handled. nor its spray @aniculnrly when the mople is removed) dvected aI close proximity to any >art of the human body <ever luemol to chanw the snmv tin rvithnsit fi-t

AIRLESS OPERATINO CHECKLIST Thc opentor should become funi l iu wnh all canponmcs, IdencUled below, befm .ntmpung to opmrc an u r h pump.

START-UP PROCEDURE (air couDled models)

1

2.

- 3,

4.

5. 6. 7.

8.

* 9. 10.

11.

'12. 13. 14.

15. 16.

17.

18.

&PPI*

YES &ect air supply hose to air control. Make sure hose s h . connections and fltringr are large enough to prevent a restricted air supply.3/8' or larger is recommended ......... - Connect nylon braided high pres" hose benuem Blter manifold (pump outkt) and spray gun (less n o d e up). Tighten connecaions seaueb.. ....................... - c ~ n n e n one end of the hig p- return hose to the remaining spray gun eonnCc(l0n and the other a d to the back pressure control valve. If nu0 hoses of different sires are used, the d k r d iwter hox is the re". ........... - If unit has siphon hac. connect ta the pump. AU ~onnecrkuu muat be Ught and the stniner should be c k n Periodically grease fitting with lubricant FUl solvent cup as rqumd.. .... - Regulator should be backed of! (dosed). ....... - Open sir supply valve to regulnror. ............ - Lmmerrre fluld section or siphon tube In solvent compatible with fluid to be sprayed. (Refer to paint manufacturer's recommenduwnU) ....... - With trigger held back or pressure rekase valve open. direct spray gun into solnnt container .nd slowly increase air pressure on the regulator to operate pump slowly, and prime system. .. - Open back pressure control valn.. ............ - Increase & regulator pressure and nul pump for approximately It2 minute u a moderate speed. ............................ - Release trigger of spray gun and walt for pump LO stall (stop running), or close pmnrre rekase valve ........................................ Close back pressure control valve. ............ - Remove siphon hose or pump from solvent ..... - Open regulator and slowly pump s o h t out of system.. ................................. - Open back pressure control valve.. ............ - M o w air to now through system for about 112 minute.. .................. ;. ............ - Check any air-operated accessories for proper functioning .................................. Shut off air supply by closlng regulator.. ....... -

YES

preparing materid to be sprayed. ............. - 19. Follor material s u ~ p l i e r i r e c O m " & w n s ' for

20. FIU pajnt container with clean painr .......... - 21. lmmene siphon hose or pump in paint

container .................................... 22. Selecr tip and gasket (and insert if needed).

kwrnll securely in spray gun. ................. - 23. lncreue air pressure until pump begins to

opente. .................................... 24. Rime system with paint.. ................... - 25. Let pump stall.. ............................. -

'26. Close back pressure recirculating control valn.. - 27. Test spray pattern Increaae air pressure (If

rrquirrd) and test at 5 psi Incremenu until desired spray pattern is reached using minimum air pressure.. ..................... -

'28. Turn paint heater ON (If so equipped). ......... - '29. Open back pressure recirculating control

v a h slowly. The pump should operate at approldmately 30 strokes per minute (top IP boaom is one strdu). ....................... -

'30. Check for proper spray pattern. whm the pump is cirdating the back pressure control vllve gauge should drop 1M) to 200 psi when spraying. -

.

'Indicws ncpl for a circulating system. NOTE: Conrml of spray pattern is accomplished by:

L Roper Up se*ctlon for flow ~ t e and fan pattern

b. Fluid prr*au'e adjunment cChmgingChc viscosity of the material .

&e.

EQUIPMENT SETUP [Uectrit or Gasoline Driven Models) The electrk or gasoline powemd auleu oualu M simple to set up and operate. Once unpackapd from the^ sbpping atan, simply c " X the high pressure auless hose to the Pwd outkt W o l d fitting and uueh the =less spray gun to che hose. Ilaaiphcm ht u to be used. aaach it to the m d sectmn Wet The elenric urut rrsuim EO VAC, 60 cycles The gasoline unit requma a @Ion of lead free gas for 31/r hours of mdnuw opentlon. Be sure to check oil level of the @soline engne. MI Binks airless Pumps are factory tested. using light oil. before shipment Thrr test fluid must be purged from the aystan before actual spray opemjons begm. Place the pump fluid section or siphon kit into a conmner of tlolnnt compatible with the m a t e d you are going to *Ply.

TO START

1. Turn the Reuure Adjuning Knob to low pressure and open the Reyure Relief Vrhre.. ..... -

2. Turn unit ON. (If gas powered start engine and t um unit ON.) ................................ -

3. If unit does not run, tum the Pressure Adjusting Knob to higher pressure.. ...................... -

4. When muerial begins to flow from drain tube on Pressure Relief Valve. close the Ressure Relief Valve. Tht pump will now build up to pressure. ... -

5. Trigger the spray gun, wlth n d moved. into solvent container until system is clean.. .......... -

6. Shut the pump OFF and OPEN the Ressure Relief Valve.. ................................. -

7. Engage spray gun SAFETY and replace the n o d e tip and guard on spray gun and tighten securely.. .. -

8. Remove solvent container and replace with material you are going to apply. Tum the unit ON. ............................ -

9. Adjust the spray pattern with the Ressure Adjusting Knob. When the pattem is righf the pressure is right Excessive lluid pressure will only distort the panem and c a w undue wear of theequipment .................................

YES

TIP PLUGGING The most common cause of tip plugging is foreign maw, paint skin, or residue in the hose or pump from a previous application. The strainers and dlters remove the majority of the particles. but some pass &ugh and occasionally plug the tip. Thorough ckaning of the q u i p m a t and propn straining of the paint are the ONLY posicln runedies.

Excessively large paint pignKnts arc Ibo a of tip plugging. Heavy a c c u m m of pigments in the a t n i n v r is an indication of this problem. h o s i n g the tip size is a help; however. thir may mate a problem of controlling the desired coating. Heavy 'materials should be sprayed wlth large tips and NO strainers or dlters. In many cues the fluid a n be m e d slightly more than that recommnded. This rot only may help prevent plugged tips, but also allow spraying at lower fluid pressure. Strainer plugging generally c a w s uils, the loss of proper spray patterns and may seem to be a plugged tip. Always check the strainer if spray patterns cannot be nuintained and the tip is clean. Or. when using RapidGkan Node accessory. rotate handk 180 degrees. TIP CLEANING can be accomplished as follows:

YES I . Relieve fluid pressure.. ........................ - 2. Set trigger lock to "locw" position.. ............ - 3. Remove cap, nozzle tip, and gasket. . ............ - 4. Flush no& tip with sohmt. then blow air

rtvough tip and visually check for obstdom. ... - 5. 6. Or. when using Rapid-Ckan Nozzle accessoq,

rotate handle 180 degrees to "Ckanout"

Reinstall gasket. nozzle tip, and cap.. ............ - position,and back flush. ...................... ._

CAUTION: Do not turn Twin-Tip b n d h ."Ll .... ..iru. .. ....I-

SHUT-DOWN PROCEDURE AND MAINTENANCE

YES 1. 2. Remove pump or siphon hose ban fluid

3. Rekme fluid pressure by aiming gun into fluid resvyoi~ and pulling trigger, until fluid ceases to flow, or by opening the high pressure release * ........................................

4. Remove n o d e tip, gasket, and insert iI used and place in solvent. ............................ -

6. kuert pump foot valve or siphon hose in container of compatible sobent... ............. -

6. Pump paint from System by opening air regulator slowly until fluid pours from gun and direct flow into paint container.. ........................ -

7. s o k t flows from the gun, direct the stream into the solvent container. ............. -

8. Allow the solvent to circulate for sevenl minutes through the gun. ............................ -

9. CLrmlate with renral short Uush cycles, triggering gun periodically to flex the pacitings tm of paint. Short flush cycles with clean solvenu are more effective than a long cleaning flush cyde. Continue until system pumps clean solvent during second or third cyck, increpx pump p- 10 lbs. nbon previous sprapng p- and trigger gun.. ................... -

*lo. Close the back pressure cimdatlng control nhh.. .................................... -

11. Ranon pump or slphon h a e &om sohmt and c o n h e flow until ayatcm pumps air for about 3orceonds ......... ...........................

'12. Open the back pressure rrcirculPring control nhh. ..................................... -

13. Shut on& supply ud trigger gun until dl prruurr is relieved or open the high pressure rekase valve.. .............................. -

14. R a n o n dlten and clean by flushing with solvent: me softbrush if rrquirrd. and forcing air from the inside through the dlter to remove midual putida. Reuxmbk when ckan.. ........... -

15. Wipe aterior parts that come in contact with paint until &an using sohtdampened rags.. . -

16. Repeat Steps 5 and 7 using petroleum base sohmt (kerosene. mined spirits or lacquer m e r ) . Close air supply to pump but keep system Blkd with solvent Sohmt should be a solution of 4 pans solvent and 1 part IO weight oil (or Binks solvent 42-175). ................. -

17. Operate pump until fluid section piston shaft is in the "down" position (or down stroke). This will prevent paint from hardening on piston shaft and the solvent will keep the residual paint pliabk ......................................

18. Rekpx excessive pressure from the system.. ... L 19. Ckan tip (and insert) with solvent ud blow air

through tip (and insert). Visually check both for o b s t d o n s . Tips should be stored in a small solvent dlkd container. ...................... -

20. Disconnect air supply, and rotate trigger lock to "off position. Pump should be stored in normal opemion positbn so that solvent will M t dram outorpump. ................................

c l e & p- regulator.. ................. - ....................................

I07

II

AIRLESS SPRAY GUN INFORMATION 'Ihc ur*.rs spny yn ir rpelaully dwigned for w with high duid pmsurn. Some rpny #Una UIC a carbide ball ud YU in chc OuId ahut-off, and a tun- carbide fluid tip for maximum wear r u h n c e and xnrlce life. A nuid tllter m y be ihmrcd in the gun when flm ffltmion is required. Tip xrmu m y be W k d to reduce tip plugging. Some spray @IN contains trigger release for safety when removing or replacing the nozzle tip. Dlffuser nuu may be i d l e d behind the spray tip, M thnt when the tip is removed. any nuid accidmtally released would not be harmful. In some models the fluid enters the gun at the b w of the handle. This .Ilows greater beedom of movement d provides a better balanced gun which, together with easy trigger pull and light weight, reduces ope"? iacigue. It is n-ry to change the nozzle tip when spmy pattern or oMce size changes are mqulred. An optional sapphire spray insert is 8\nilabk which must be as large or larger than the spray tip oriece size. When installed in the nuid passage, rhis insen causes an increased fluid velocity which is an aid in fluid atomization. These inserts provide a "soher" spray p a " and reduce "tailing" of the panern edges, especially when using lata or vinyl base materipla.

Heavy Centered Pattern 4 Distorted a Panern

CLEANING PROCEDURE FOR AIRLESS SPRAY GUN

1. Worn tip. 2. Fluid will not spray with airless.

1. Plugged or worn noala tip.

1.

2. 3.

1.

5.

6.

7.

8.

0.

10.

11. 12

# Hour Glass

SPRAY PARERN PROBLEMS

1. Fluid too cohesive. (Adhesive-tvDe materials).

Tails 1. Inadequate fluid deliwry. 2. Fluid not atomizing. 3. Insufficient fluid wlocity. 8 (I 4. Material too cohesive.

Panern Expanding & Contracting (Surge)

1. Pulsating fluid deliwry. 2. Insufficient air rupply to pump. 3. Leak in suction tube. 4. Pump capacity too low. 5. Material too viscous.

Round Panern I I . Worn tiD.

2. fh'" spra; material with airless.

YES

drain out any s o k t or paint. ............... - R a n o n spray gun from hose- ................ - Remove retaining nut, tip, washer. gasket, insert, and fflur from spray gun. .................... - Place removed parts in container of compatible solvent for soaking. ......................... - Clean spray gun with Solventdampened rags. Do not submerge entire spray gun in solvent; probe with a ~h bristle brush if necessary to thoroughly clean.. .......................... - ~wperr spray gun for broken or wom parts. (Refer to Rn Sheet.). ....................... - Lubricate needle. packing and dl points of wear.. ................................... - Clean tip, washer, gasket. insen, and mer with air blow gun and, If required, a sMf bristle brush.. .............................. - Observe tip insert and dlter by holding up to light.and inspect for cleanliness. ............. - Securely replace tip, wpsher, gasket, insert, and tllter In spray gun. .......................... &

Fill unit with solvent to check spray gun for

Rekw dl pressure from system and

Replace spray gun on hose and secure. ........ - UU, opendon. and proper spray panem. ..... -

R.rmdy

1. Increase fluid pressure. 2. Chenge to smaller tip orifice size. 3. Reduce fluid viscosity. 4. Clean gun and filter(s). 5. Reduca number of gunr using pump. 6. Install properly matched sapphire insert.

1. Slime ar above. 2. Chanoe to air atomized method - .~~

1. Clean or mplaca nozzle tip.

1. Change to a smaller tip orifice size. 2. Install pulsation chamber in system or drain

3. Reduce number of guns. 4. lncreese air supply to air motor. 5. Remove restrictions in system. Clean or

n m m screens or filters; use larger hose or pump if necessary.

6. ln rpsn siphon tube and hose assembly for leak.

7. Reduce fluid viscosity.

1. Replace tip. 2. Increase h i d pressure. 3. Thin material. 4. Change nozzle tip. 5. Install samhire insert.

axisting one.

6. Change to air-atomizing system.

1. Increase fluid pressure. 2. Thin material. 3. Install sapphire insert. 4. Change Io air-atomizing system

TROUBLE SHOOTING Tmubk I h u u Spitting Gun $41 .*

Gun Will Not Shut Off

1. Air in system. 2. Diny gun. 3. Needle cartridge out of adjustment

or damaged. 4. Broken or chipped needle seat 5. Packing nut too tight or not lubricated. 6. Twist tip or nozzle tip screen dirty.

1. Worn parts, broken or chipped needle Met.

I 2. Needle cartridoe out of ediustment

Gun Does Not Spray Any Fluid

3.0invgun. - 4. Packing gland or nut too tight

1. No paint. 2. Plugged filters or tip. 3. Broken needle in spray gun.

TROUBLE SHOOTING AIRLESS PUMP

footvalw. 7. Dry orwom peckings. 6. Broken or worn ball or velw seat& 9. Air motor pinon shah separated

from fluid shaft. *lo. Back Fmwn Recirculating I CantrdV.luaopen.

1. lnspen Wnnanions and siphon hose for leek. 2. Disassemble and clean gun. 3. Inspect needle Canridge and adjust or replace.

Air Motor Valve or Auto Cycle Valve Leak Under Load

Pilot Valve or

4. Replace damaged ne& seat, 5. Lowen and Lubricate packing. 6. Replace twist !ip with standard airless tip.

1. Inspect spray gun. Replace defective pans. 2. Inspect needle canridge and clean. 3. Disassemble and clean sorav oun.

Clean noale tip screan.

1. Surfsce plates or valve block plate nuck. bells seats scored or diny.

2. Auto Cyde valve out of adjustment

1. Pilot valve or auto cycle valve seals

4. Loosen gland or packing'nuinid lubricate needle.

~ - 1. Check fluid supply. 2. Clean filters or tip. 3. Replace broken needle.

Trouble I ProbabkCauu Insufficient I 1 Nonrint - 2. Foot strainer clogged.

3. Pump will not prime. Material MaterialFlow. (Pump operates but does not stall) I too heew.

No Material Flow (Pump not operating)

1. L o u of air pressure. 2. Plugged supply lines, qlters or tip. 3. Icing of air motor. 4. After e long period of norage, piston

c u p may be stuckto cylinder wall. 5. Pilot velw or autocycle stuck. 6. Air velw actuator piston nuck. 7. Trip rod adjustment too loore. Air

8. Malfunctioning or worn air valva.

piston hits on bottom casting before tripping pilot valve.

Load. Air Hissing During Exhaust wall scored.

Auto Cycle Valve Move Too Slowlv

2. Air motor piston cups or cylinder

2. Actuator piston or valw surface plate d im or bindino.

Auto Cycle Valve Hissin Constantly. ~ o s s ol'pump Power

Matenal Flow Sluggish Or Pumping On One Stroke Only

damaged. 2. Auto cycle valve out of adjustment.

1. Insufficient air pressure or volume (CFM). Too small I.D. hose. Too long a hole. loo small a compressor. Kinked or tangled hose.

or unseating properly. 2. Fluid piston ball valves not seating

Ramedv . 1. Check fluid supply. 2. Clean foot strainer. 3. Thin material and operate pump more

4. Repair leaks and tighten connections 6. Tighten conmction on siphon hose.

6. Remove pump from paint and clean

7. Replece packings in accordance with

8. InrpCn a d replace broken or wom parts. 9. Insp .nad repair.

90. Clme Vdw. tf closed and still bypassing

slowly to get prime.

Check for damage.

velw foot.

pan shea

fluid. reoair or reatace valve.

1. Checkairsupply. 2. Clean hose. filters, and tip. 3. Install en oiler with antifreeze. 4. Increase air pressure until piston cups

lomen; then decrease air pressure for normal operation.

5. Rem- and check for proper adjustment. pbgglng. wom or damaged pans, binding or leaking seals.

6. Remove and check for binding, lubricate. 7. Tighten trip rod adjustment screw. 8. Refer to air valve pan sheet for proper

1. Check for sutficient air supply. 2. Replace worn or damaged parts.

1. Replace Piston cups and lubrlcate. 2. Remove. clean and lubricate.

procedures.

~~

1. Replacedamaged pans. Clean and lubrica6 2. Adiust auto cycle valve (see pan sheetl.

1. Replace damaged parts. 2. Adiust auto cycle valve (see pan shee11.

1. Check air su~ply, hose length. hose ID.. pump air requirements. Check hose.

2. Remove fluid section and inspect for wear, stuck or broken pans, and clean or replace (see pan sheet).

3. Replace Piston cups or cylinder Isrr nan rh.11

GENERAL COMl Factor

1. Means of Atomization

2. Pattern Control

3. Air Volume

4. Air Pressure Requirements

5. Fluid Pressure Requirements

6. Fluid Delivery

7. Air Contaminatior

8. Materials

9. Material Preparation

10. Maintenance

11. Product

12. Spraying Contamination

Advantage

13. Atomization

~

7lSON Alrhu Spnflng w ConHntional Spraying

High wlocity ofnuid using hydraulic pressure thru small orifice. . Nozzle shape and size-must change nozzle to change pattern. Approx. 114 to 112 of air spray (100 psi).

High pressure (100 psi) required.

600 to 4000 psi.

Medium to high delivery. Provides fastest application speeds. Excellent for large areas.

More werspray (material that misses the object) but lest fog and rebound (material thal bounces back from the surfacel. Not all materials can be sprayed. Requires uniform fine grinds (particle size 0-.006). Heavy pigmented, fiber filled. abrariw or cohesive materials will not w o k Requires considerable care in preparation to ensure proper patterns with no tip plugging. More required because higher pressure pumping equipment and smaller nuid tip orifices are required. No contamination from air line impurities.

Materlalr may be sprayed into avitiw End corners with little rebound coming from Lhe opening.

Generally coarser atomization. .

1 I fluid stream tom apart by jets of compressed I air. 1 Control or air and nuid pressure provide I complete control of pattern. I I 4to20CFM I I Medium to low air pressure best I 150 to 75 psi). I Low pressures-generally to 16 psi I nnozzls. I 1 Low to medium delivery. Usually not more I than 32 02. per min. Less speed than I airless-more control. I Less overspray. More fog and rebound. I ProPortioMl10 the atomizing pressure. Highef I pressure-more fog. I Materials that flow can be sprayed. I I I I I Less care required. Follow material supplier's I recommendations. I Leu required because equipment is 1 morebasic. I I Impurities in t h air supply can spoil I ttmfinistt. I I Difficult to rpay into cavities and corners I becaure ofdm large amounts of air required I to atomize the materials; create an air cushion I which inhibits paint dephition. I I Fineatomization for all high-qualityfinishes.

AIRLESS SPRAYING COMMON TERMS USED WHEN DESCRIBING AIRLESS SPRAYING ALrlus Spraying--The method of using high pressure to create high fluid velocity which uomizes paint nutetial without using air. Airless Pump-A pump designed to ueate high nuid pressures which are needed in airlw spraying. Siphon Feed Pump-A pump that has a hose connected to the Coot valve which enables the pump to siphon material out of standard containers. Solvent CUP-A cup put on a pump around the upper packings which wil l help lubricate the pump and carry off any excess heat caused by the operation of the pump. Siphon Tubc- lk tube and hose assembly which connects to the foot Valve of the pump. In-line Filter-A filter which connects in the paint line of an airless unit before the spray gun. Spray Gnn Swivel-Connects between the spray gun and hose which makes it easier to work with and prevents tangles with airless hose. Airless Gun-A special gun designed IO withstand high pressure and has only one fluid hose connection.

AlrIea# Node TIp-A nOnie tip made of tungsten carbide with a small hok in it in sues from ,007 ~0.072 of an inch. Spny AD&--The lnek that is cut into a nozzle tip which will determine thc spray fan p w m . OrUIce-The sire of the hole cut into a nozzle tip. kua (Mlm Spny Orfilce-Pre-Orince)-A up placed before a no& tip with an orifice of the m e size or larger which will add velocity to the material-gives c o n s i s ~ c y and h e r uombvi on. "Twbt-np" Node Ckmeer-Facilitates the cleaning of airless tips by being able 10 reverse the tip and blow back paint rhmugh tip to ckan it

AIR-ASSISTED AIRLESS

rcmacsrss M lack mehetnacb mnsd mm me compessed au a t m a - IIW pocezs. and asless rqunes snct a m m e to salely. mantenam. and clssnupmstnr~

Comblninp the .dv.nta9.. A dence that can m o v e ellchncy n capretsed air and airless spraynp IS a pant heater. such as the one hat m y be wsoended I r a n y o u spray bcom wall Heat. whsn p r o p l y appled to coatigs. rMwes voco~lty. m o v q Itow whm uunp materm mat IS mmned mm heat !n stead of excesswe amcimts 01 expw\slve and harmful solvent. one can a t m e coatmgs mm lower air and f b a pressures Ths at1 a635 up to kss lop and overspray. meased covera@?s. anti reduced wrmg Inns Heaters. however. tollyme hgh amunts 01 ekclfmly. re owe mantenare. and my be npracb CBI wml some catalyzed coatngs (Re. mnbn. by not to have m e han 15 to 2011 ollkndhcsebetweentbheater and me spray pvl--dcvlg sa CBYLCS heated matar81 to cool on )

The next sep toward mmm clk U a C Y was combnnp me besl leahrcs of compcsssd ar atanuatm nd a m a t m m to fm a n w procsss called an-asynsd a r k s Tho poem pondss laser apphatm of mtermi man ccn pressed au. a toll spray that r e w k n re. bced lcgand waste. and me -to m-ebate nto racesses and tav~er w h k still ache- a Ire atmuam. Wmch IS somporlantwtthwood Thssystm waks best wml slow IO medun poduc- too Ine speedr. rogreater man 20 It/ mn. and mm to me&m n s c m y materr aIs m a l ” 28. to 32-second Zam 02 H IS best wted tor stains, fillers mes and lacquers

A hlplcal system c o ~ l s t s 01 a s p a y ~ i m apump,twnehoses andclean cwnpewd as wim adequate peswe and mune It may be used mm snail containers. such as a 5galkm W e t fw small #YS. M i t may wphon lrm larpe 55gaUon drums lor large pts

An arasusted asless spray com m s features fand n bom ar and ar- less spray guns n uses specmi nua noz- z k IIP to ~anlally a t m e (he material us- np (he asless pmcipk prevously Q- C W

Atmat lon men IS completed m c a ~ r K s e d ar from the hcfns 01 me ar nozzle wrrch wlounds the airless 10 Without the canpressed air. we wcud

Oil and Wator Extractor

AIR-ASSISTED URUESS

It incorporates the best fe8tures of compressed air and rhe best of a i r less, such as fine fin= ish approaching thst of conventional air spray, not 8 coarse finish llke that of airless spraying. And It producer softer spray patterns.

and oWe lmiture. cabmeny. slue fixtures. and nullwork to name psi a few TIUS paess can handle a mde ramp 01 b w rates and newly devebped materlal tcfmlatm. ncttxUrg the polyuemanes and #vesters mat gve wood mat popr Lar wet bok. A mde selecton ol a&ss

Tralnlng oporston m d nulntalning oqulpmont These examples KNEW mpressive. krt pw(- llg.8e.s 01 m tyw don't mnthebxunmmeeqvlpmenl H your present caprcssed air system 6 not pa?%ty a w l e d u 6 poorly ma-

Be prepared to Invest some time in training your operating person. ne/, . , Operators should learn to a&st to get maximum benefits.

h lm 01 bamfer ellkkncy. let's r e view Ihe most popular system5 used n spray "p today: &Way . . . . . . . . ,2596 Anks . . . . . . . . . .40% &--asrs(eda#ks . . . . 40% Eleclrastabc . . . .60 to 85%

pjrtess and air-zssled atties haw a p proxinsbly Ihe am banslef elhclency. so use vhy me ai-asslsled abks? 84 cause it imrpaates me best leatues of canpessed u and me best ol auks. ard as a ha wll approadng mat 01 c m " I a i way. not a co81oc hsh keSto l akkss swam. andit PO &as row spay panarm.

AfmaUe rpar panem can be adrevad cn many 01 me newer ar-asst-

auks s p a y g ~ g . Large w e UPS pemrt a weater range 01 Ian sues man an anple tips. Don't be KXSM r some one says t a t ycu can Mnply a-t me panern size by b"g (he a m t of at- ai-. L h r ~ Y) would my deleat the pwose 01 akw--ted air)ess.

Yw also can expect less wear on me Awd IIP andm paw. k?ss thance ol me 0 PIu@~ing and hydraulic wctm. and reduced bodn mamtenance. However. to gain Ihe5e bmek. be prepared lo nvest some lme n U a r q yaa operating per- Sanel. Ths plocess IS dillerent man el* er an u arks . and (herelwe (he spray owatws should kam to a@ust meir technlqves to get me m x m benehl from it. Remember to encarage opera- tom to Ee (he lowest pressures Mt mll prDduce a satslactcq panern There are m e ccf~nc#s 1u Inem to vderstand and pertom man when m s w a y q leach them mat whwl me panem IS npnt. the plessues are rr$t. oolnp Y) will m. prove yw appbtm efllcencv

113

PERFORMANCE CHARACTERISTICS OF SPRAY METHODS

~ Airless Spray

Recent attempts to reduce emissions and haZardOUs Wastes through Improved application efficiency has led to refinements of all types of spray atomization systems including the process of air assisted airless. assisted airless is now available that includes the benefits of HVLP lh i rh vnlrlme

A new generation of air

l Coarse. , 20-3@?/0 better than air , SDKIV.

.... ~ . . - - ~~

Air- Assisted low pressure) atomization. Assisted HVLP. quality, EPA acceptance and superior finish of conventional HVLP.

This new system is often referred to as Hydraulically I t combines the speed of air assisted airless with the finish

~- I Limited to hgh and very , high flow rates, normally , over 25 fl. ozlmin. I Less overspray and fog,

booth maintenance Is low.

Finish Appearance Transfer Efficiency

Fluid Flow Control

. Booth Maintenance I .

Pattern Adjustment Tip Plugging

Equipment Lib

Energy Consumption

Noise Emission Level

Air Spray Excellent. LOW.

Limited to very low to medium flow rates. usually less than 30 II. ozlmin. Lots of overspray and fog. so booth maintenance is hhh. Yes. Virtually none.

Very tong, because fluid pressures are low.

Poor efficiency in atomizing liquid. High air consumptlon. Noisy. High.

I NO. 1 Yes. Adequate filtration 1 required. 1 High tip wear and shorler ' pump life because very high

h i d pressures required.

Good effkiency in atomizing I Ilauid. I Quiet.

LOW.

Hvdraullcallv Assisted HVLP . . Verv aood. _ - 50-60% better than air spray. Wide range of flow rates: normally lrom 5 11. ozlmin to over 50 II. ozlmin. Least overspray and fog. Booth maintenance lower than airless spray. Yes. Yes. Adequate filtration required. Less tip wear and longer pump life because substan- tially lower fluid pressures than airless spray. Moderate eflclency.

Quiet. Low.

THE LINE

HIGH TRANSFER EFFICIENCY SPRAY APPLICATION SYSTEMS

anufanurers perloning a finish- mg operation are charged. M among other things. wrlh Mc

resoonsibtlity 01 complying wm\ the Clean Air Act as amended in 1971. C a l k " ftnlsners are well aware of proposed amenamens to mls rule. namely Rule 1156 lor fumrlure finshers and 1107 for metal fimsncrs to m . p n a few. b. sentially m e x rules wuire a minimum of 65O. transfer efficiency ana a limn of 2.8 lB/gal 10.335 kgn) of solvent in me matmgs mey use IO finish these prod. UCI. wna! is haopenlng w a y in Califor- nia will undoubtedly spread and affea hnisntng owrations nauonwwde.

Altnougn many factors affect the transfer clitciency of a finishing operation s u m as p r w u n shape. sue. tenure. racring of pans. operator Iechnique. aartng material. method of application. m o spray tooth performance. me Envi- ronmental Proleaion Agency (EPA) leak mat the vanaole wilh me greatest inllu- eice IS the method of atomuation. In !inisnmg rooms today. electrostatics. lurbo-spraying. and power coating are mown for their hgh transfer efficienclcs. tompressed air atomization. on the Dlher hand. IS known for 115 low transfer

ny the inefficiency of cemin forms of spraytng? First. let's examine how atomizalion is

eneratea. AII methods of spray linuhing US1 atomize Ihe coaling material, which ally means we are lorming tiny droplets coating matena!. shaping m m into a ray oanern. and owinn them forward

Jerry P. Hund. Binks Manufacturing Co.

10 be coated. All of this requires emrgy. The amount of energy requircd to atom- be a mating vanes.depending on Ihe Cosrirg material. Obviously. Less energy is required to nomue smn when a m wrea lo hgh solids urethane. Atom-- lion is thus developed when eilher mechanical or eIccRIuI forces are employed erlher separately M in ambin& Wn. For eumpk. air spray. airlot. and air-assisted aitless rely solely on m t et" forces to create atomuation. Eiearostatics. on me mher hand. rely on

I The hear! of tho I PLV Nstem is tho

I

mechanical and eleCtriCal lorccs to arom- Oe a mating. All m." of atomization are Believed I O require the same amount ol energy pnor to itr entrance tnto me Spray gun. Anyone who ever tned to punt a car realues that it takes a vev large compressor wlth plenry of energy IO dc me job right

Unf0r"lCly a great deal of energy mun Be generaled in order 10 account for waste. O m at me nozzle. thc energy lorming alomuation is krgely waslec Needless 10 uy. we sacrifice energy lor qwlty of alomuation.

nu in man's continuing search to reauce energy loss and improve T transfer efficiency. otner metnoas 01

atomization were developec. In me 1940s. elecfrostatic spraying was intro. ducW to inaease transfer efficlcncy Early erpcnments wlth mechantcal ant elecmcal forces 01 energy led to same wry impresswe levels of high lransfer efficiency. Unlonunately. not all users could benefi from eIenro~tattcs Mcause their prcUuM were not condunlve. had tm many recesses. or because tne meMod simply proved impractical

In mC 1960s. me airless process DO- neered a new era in Ihe finishing f te i j

Large jobs requiring faster and neavle' coverages tound airless atomtzat13- more pranical than air or electros1a:i:s Where a matser atomued llnisn was acceptable or where subseauent leveitng and sanding were performed. airless 8tOmiZatiOn was used Because i t pro- OucM a soh. clean spray w h m was nnnmzlmlfrh, A M .-Y.-.--*

rpnying systems emerged. Air-assisted

best foatums of air spray Jooo wim fhd best of airless. This system $hived to Mmw gad atomization pualilies while at the same lime reducing fog and over- m y w h i i bods to inefficiency. When used under ideal cond~ons. air-srsisted

fer rtficiency and electrostalic air- misled airkss f m . 7 0 to 86% transfer

ne process of spraying that has rewived increased anention re- 0 C e M l y is hgh volume, low pws-

sure spraying. High volume, low pressure spraying was used by vacuum deans salesmen years ego to propel punt hwn an attachment a"d to Me vacuum cleaner. Today's systems are more advanced using a turbo- compressor Milt producas a supply ol

oil-hoe compressed air ai a voiume of be" SO-250 t?mn (2.50-7.08 m5/ min) but with an air pressure wavy t" 1-7 poi (6.8948.2 kPa). Since no e n expansion d sompressd air k oxitin3 the spray gun, a r" ef f im use of .OMW gently pmpels Me atomized paint to Mc wcfti surlaca. Umough Uus p a s s delivers high tranrfer effi aen6as. usually between €mo%. II has m limitstians: il has #ow application weeds; requires speoal mmpetsbd air considerabons not usually found in IVX. nul industr*i Senmngs; and is rltpensin to puhhPse and repair.

ossibly one of the n m t innovaiiw rylw developments to come along P k a process called bw pressure,

b w vokme air atomization (LPLV). This wss at firs1 glance looks and operates similar lo air-assisted airku; how- swr. tl is a refined air atomization xoccs with exmptionally b h transtor 1ffinCy.

Why low pressure. low volume air ilomizaiion? Transfer efficiency is ireatiy imprwed over air, .irks. and iir-assisted airiess. Ratings of 6o.BoDk w e been oMained thus far. Most low to Mium viscasity -lings such as Lac- wrs. stsins. and glazes can be ouc- esshrny atomized with low nuid pres-

ailless W a s devebpdd to combine fhd

*ss could givs us close to 60% trans-

otkmcy.

W U m . 68'-lSS'F (xr-oO.SC). dry.

COMPONENTS OF A HIGH TRANSFER EFFlClENCY

SPRAY GUN

vhth true air-usined airless. Atmuat;on ~ a u r s by impingiq b w amounts of compessed air. hDm 5 to 35 psi (31.4 to 241.3 kPa). h0m (hr hvo small holes b a t e d on th nuid tip asembty into thc nanened fluid stream. TfKI ux11ca1 flud tip assembly causes Mc side pori (hun) air to be direcled against the flanewd fluid meam as opposed to an already aiom- ited spray. as with aif-assisted airless. The I w O Small air jets are ¶he key to material break up, the elimination of tails in the pane" and keeping ¶he fluid tip assembly clean. By controlling lht amount of side pocr (I") air, the spray panem rue is adjusted as previously bcscribsd. The plastr flui nozzlt also eliminates the use d adddional seals behveen the fluid Up assembly and fluid ryUZ1e.

The b w pressure. low volume air atomization prccess has been very well accepted by h " r e h i i h r s . industna~ umn. wlomativt minishers. mite name painters. ud ouwn. w i its hgh transfer efficiency ntings. ease d apph- trtion. and minimum quipment re- gund. tl m y pmve 0 k mC honest mahodof~tbr l r incamorasrad ~ - - - - ~ ~~ .~

wnstrwnr~pressurearps,tmnks. a i r a t o m i z o t h ~ . w low pressure pumps. Fbii tips rang+

m h the end w n have many options o w n to them !hat would A make their finishing operation more

in size hom 0.01 1 to 0 . W (028 to 0.91 mm) and p d u a spray panem from rimy mondmupto IT (u i .8 mm) in we. d ! i i pMfamuw+ tigures discussed

signed m y gun. they can rko "fit q u i p " . I your m m systtm is many oxstmg manua.l of wtarutic a3 improperly adjusted or poorly maln- " iz ing tpny gunc by changing to th Wned, fhdn MY new process when dem- newly Wgnd M IUZZ~, hid bps. mstrated to you will w a r IO be a grear nuid nozzle. O m g seat. and in-line fluid imprwlmem. In fa. exaggerated cost filter. S i erkting taped flus needles savings M d trawler rthwncy tgures are used, mwal spmy guns u n k may be possibk wiwn companng one "leathered" by UM operator in mC same finishing system exercising full operator manner as a amverRiwI gun. mtml to anolher Crushing system that How &as bw pressure. bw volumc has no operator wntrol.

air atomization wcxk? The fluid stream Spray finishing poses many prcblems exiting a "antionel nuid nozzle is t h t u e in m ways unque and at mond in crwt aeclion. Low pressure bw limes diniin to aaomplish. The sic- volume rpny guns axil nuid and air mssful oppllcrtpn is o n !hat insists on separately Wcugh Me fluid nozzle and quality oxtings. IpDId Dy qual i spray. imo a Lbconduy fluid bp assembly. ers, wim quality spray equipment.

The exilinp malerial is of kw pressure.

umough W W k r y t h r here don1 Come k tM box Wl thc

under 100 psC (589.5 kpa), and UM~P md h n d -cptsaye- in - Jerry Hund is assistant director of mion LS ~pposed to I hiher muun training at Binks Manufacturing Co.,

Hot Spraying

10T SPRAYING f one wae u) list all the advantagu of 'ha spraying.' istwiCy mml would have Lo k hra As ambient ccndi- ions change. so does the viscosity of any given mttrial TI^" conmlled hear can be added to stabilize tbse onditionr insuring uniform rcsulls day after day.

leforeconsideringall theadvancagesot usingahcsdspray ysum, an undastanding of the basic ammidon proass sing cold materials is requictd. When a material is applied y spraying. it is desirable to have b e ma& quite thin to rovide fme atomization, re& liquid enough u) level off fur applicarion. but sc( up quickly loprevent sa&ng.

:OLD SPRAYING i'hen cold spraying a material. solvents arc normally addcd > h e spray paint formulacions Lo prodlre the following ondiuons:

Bnakdo~thecohcsivenaamofthematcrialbybwering S VkMity.

Solvents cause the molpial IO be ruomizcdfiy@e m Ian).

Solvents arc gemrally blended so h most of the solvmt laptcswon Ihc paint paniclcsmch tbcstrrtace.

When the paint pardclcs Rach the surface lhcy &auld here while the remaining solvenu e- thus keeping e parIides wet enough Lo &w out bm not so w a that gging occun.fig. I )

EVAPORATION OF AToMmTloN I \ FAST SOLVENTS

,\! b LLV EVAPORATION OF ..... O REMAINING SOLVENTS

ROPER USE OF SOLVENTS ~pmpr use of solvents can taw ccmditim which could limslcly L d to such probluns as

RK use of IDO many solvents can minimize film build cause the splay gun dcpsirr a fib conraining more sol- nu and less solids with each pass of the spray gun. '

117

ZTheaddition of an imppa Wtkycrlypeof solvents can possibly change ahe chemical or physical name of the mattrial l'his may cause problems such a~ m g e peel, dry spray. solvent popping, and material livaing.

3- the ammization of a mataial to ocnapmprly. prsise considuations must k given to ambient air rcmperature, humidity, atomizing prssm. and the physical pmperries of the solvents king used. AU of lhesc facurs effect the cvapraation mte of the solvents.

4 . h the cvapration of solvents talrcs place, Ihc pain1 par- ticlei cool down and evapontim is delayed The higher the air pusurr or fluid ~rcrr;urc. the faster emption talres P k

5.m colder thepaint particle is al it strikes me slrrface, thc mon liLely tha~ one of the following condidonz can OCCIP. iapeare m rcqW,flOar-out time: inacace of solvents bciig wpped m theapplied hlm; and nmsorsags cawed by watcr king amdendinto the paint panicles cronm the surface of tbe iccm bcing SpmyaLFi. 2)

NOTE. Tempfatuns m air spray penem am approximate

HOT SPRAYING ADVANTAGES Hot spraying was developed to ovawme some of the pbiuns prsaiarcd with che use of solvenu in thinning paint

Hcating a material to a t e m p " range between 1% Fand 16oF will pomoce conditions that can be upecud to mate thcseadvantags

I.cOnaant viscosity mtml of Ihe "ial king sprayed. IC~~IIUCSZ of fluauaring ambient mpaapmr.

2Acnaate conml of the material umpaaMe rhroughoutthe day, regardless of ambient tempaaturc.

3.hfaMawial is thinned by heat instead of with solvents

fM *g.

ATOMIZATION

RESIDUAL SOLVENT HIGHER EVAPORATION TEMPERATURE PARTICLES

m.0 .. SURFACE

v i s i t y changes with the addirion of he&

When only viccodty conmlis 4ougk then "tmamialw9 not have IO be h e a d above 120 F teause tk ~IUICS

Fig. 4) viwosity change OCEM before lhat point is rc&cd. (see

Vlacoalty va. Temperatun (Flg.4)

VISCOSITY CHANGE WITH HEAT (REPRESENTATIVE MATERIALS)

If hum fkrbdf is requirrd. then rhe mamial should bc batedjrrnMdeJihebwutwigpointofrhesolvents being p3cd in Iheblcnd In an rirlessystcm m a m i a k a heated above rhe wig p i n t lo &eve fiw mmi7.ation. Check with the mataid supplier for the boiling points of the aolvenf being uscd in the material formulation. Also check thc highs! or rccommcnded tanperaMe Ihe material should k hcared to.

BOILING POINTS OF COMMON SOLVENTS As a guide to operating a huucd system comctly, the chan Wow listrtheboilingpointsataunosphaicprrss~ofsMne cmmon solvents used in making solvent blemk (Eg. 9

NOTE: Temp.raIun6 in air spray p*Hem a n approximate. TEYPERATURE IN F

I18

SIX BASIC SYSTEMS 'Ihcrrmesixbuicsysrrmr which can kuscd forheatingrhe mamid or akin a spray system:

l h w presswe ooncirnrlating rynun which is re"- mendcd u) k used when high pmduction mes ate qukd. the system is king used continuously. and the ma(erial does MI @ CaLMnt C h l h I i ' a (pg. I)

M D

2Low pssure siphon-fed pump circularing systun with non-circulating heater is rccommcnded when mataial must be kept in cimlation or when the syncm is not usedon a continuous basis. Ihe m a d is kept in heated circulation at the h t of the spray gun Warm "ing msrtrinl is mixed with cold incoming maruiaL which red- mataial heating cost (Fig. 8)

1 -

SLOW prcsnae hot air and heated mslaialc Jyjtcm. In this system, both the maLCrials and atomizing air m heated ?his method allows the materials U, nach h e surface ai a higher tempaaturr, which improves flowout and apparance. However, special considwtim must k given to the solvenu mdmaraia lbc i igd (pil l)

w m " o J ~ Y(YLLDI.AL

3 H g h pressure hcactd airless circulating sysm is recommended when a fine T i is rquind and the airless proass is king used. Heat may alsobeusedtoaidin the atomization of a material which nomrally CaMot k srravcd in a cold

;system. (Fig.

119

U M Y QUN

/ Automatic Spray Equipment

a GENERAL DESCRIPTION Automatic spray painting nuchines a n be designed to coat aimost any type of product regudlep of shape, size, color or material. The huic design of these machines will conform to one of the following type motions, excluding minor changes which m y be uud to suit the particulu product.

1. Hori2011t81 Ruiproatinp Machine This c o l t s Il8t objects such LI steel plate. plywood. etc.. which can be wried on 8 Lydown conveyor unda the +ny gun. The motion 01 i horizontal recipmciting machine, towtether with the movement of the conveyor, may be dsa ibed 8s 8 series of “W’s”. The spny guns ue fked i t right angles to the surf81x of the produd. When using one spriy gun with 8 6 Inch spny pattern, the product will move 3 inches for wery stroke of the m d l n e . For a more uniform coat. an ova lap is provided to cover the pmious moke using one h.LI of the effective portion of the spny pattan of the prrviour strokrz The spny gun moves dr Lrvha prt the product and is tu& ofL The wn ir turned on six inches hefore rrutiq the next stroke. Triggering the gun helps to keep the nuid nozzle clean. Recommended for up to 25 feet per minute conveyor speeds.

2. R o t l y S p l y Machins T h e do the same bulc opntion LI a boriwntd reciprocating mehinc. but ue able to operate i t higher conveyor c p e e d ~ The machine mutes at .bout 20 RPM md the spny pattan “ r a g e irr conjunction with the conveyor. covers the object w l t h i m i e s o f o ~ p p i n g & h e httertheuc. the more unilorm the autiog Four arm mtary rpny rmch iw w recommended for up to 50 feet per minute. Eight rim rotary spny mehiw w recommended for m y conveyor aped over 50 feet per minute. A limitation of this “chine k that I t anno t handle ibndve rmteri8Is beclue of the rorrry d s it UYL

3. Spin& k c h i n a An automatic spraying system consisting of ex.

bust system, conveyor (chain on edge typ) and tpny gun controls with the exception of lo8ding 8nd unloading portion (*optional equipment). Most types of products mrted rlth thk mrhine conform to spherical or cylindrical dupes. Square dupes require two rotrtlonal u n k The object k placed on i speckuy designed workholder and routed or spun in h n t of one or more spny pnr For 8 fine uniform Ilnkh the product must he muted at l e d 8 minimum of two revolutions In the fmnt of each spny gun Depending upon the shape 8nd dsc of the pmduct, the minimum spaang of the work holder is n o d y every other pin; greater pacing between work holders a n be 8s desired. The spindle conveyor ch in k 8vlhbk in 1-112.2, or 3 inch pitch, depending on rquhmcnts Cob

nadr *Automatie badlog and unlo8dlng c.ll he utilihed when prk knd th&ves to rutormtic bandling.

Dedgned to produce i vatlcll or ”up and down” stroke. These nuchines ue n o d y uud in con. junction with overhed conveyor systems, but can be ldrpted to other typc Tbe deign of these nuchiDer and controls ue determined by the size, stupe, type of nutend being rpnyed, production requirements .nd budget ai- bred by the customer.

veym path an be unnged to suit the indivMuai

4. Vrticll Rwiprocltlng M.chimr

B. ADVANTAGES 1. Uniformity of the mating on the product 2 Cut- down ol product rejections 3. Minimum b u m elanent. 4. Paint n v l n p 5. In mort ua. production rites CUI be increased.

1. M.taidnving~

3. lmproved product q w y . 4. RnLb unilormity. 5. k b o r IriOgL

C JUSTIFICATION OF COST

2 lnurucd production.

D. CONSIDERATIONS IN SELECTING A PIECE OF AUTOMATIC SPRAY EOUIPMENT 1. size and configuration of pmduct. 2. Conrryor sped-imum and mlnimum 3. Production rquhrments (to include future plus). C N m build and flnisb required. 6. Type of spray guns being uud.

7. Tvpa of q r r y m ~ : hot spraying. electrostatic.

a TYP 01 e ~ m ~ y ~ . 9. Conveyor dze.

10. s p n y booth rize. 11. s p y booth typcrrtcrsrlsh or dry type.

6. Mehod Of MtRkl 1tonIhtiOn (lid€% 01 Cob m t i o d ) .

circulating or dead end.

E. OPERATION 1. Material is supplied to the automatic spny m-

china by standud pressum clnkr or pumps for mnventioml applicatiom. d l i r les~ high pressure pumps for iirler spraying, or where production wamnts, the circulating system is wed for supply.

2. h e spny guns cover the product with a spray pattern which is pmpendieulu to the surface. Muering thespny guns at the end of each stroke. overlapping at the rnmerate,andouinL.ining the proper spraying distance produces the required udonn l ty of the coating.

F. LIMITATION l . T h e r i z c u d e o ~ t I o n o f t h e o b j e d t o b e

mated. 2. The Nm thickness cequind in one pas though

the machine. 8. (hst of the quipment murtbe justitkd in "id avings, production incmnsz and/or pm duet unlfonnlty in one or two yeus.

G. CONTROLS The contmlr tht are aniLble on tbac automtk spny machines a n be either rcmhutonutlc or fuDy automatic. "be controls an be designed to hve thc ability to idmtify the shape rad rize of the prcduct and mat OD& Its rurfm m a with minimum over. m y . Automatic color changing unitrue av&bk to

change from OM color to another. Skip spray devices are ivrilrble in order to prevent spray pm irom operating when t h m is M pmduct p m n t on the conveyor.

A rpechl device which has the ability to carry out rkip spray function, is a pin memory ring mounted singly or In a series. The memory ring is connected to a pamitic drive which powers a.nd movestthe memory ring In direct relation to the conveyor speed. Each ring is connected to a sensing device mounted along the conveyor. Thir may be 1 witch or a photo cell. Ar the part passes the sensing station, a signal is given to the timer unit Thk dgnal emrpizn a aolenoid which extends i number of pins in the rotating ring. For example If rich one of the 100 pinr could have a memory assignment of 4 inch= &cross the product, the ring would retain this information for a d i g w e e upto 400 i n c h a By vuing the memory assignment or using additional rings longer distances cm be obtained.Thepins, modng in Ume with the conveyor, advance to an output witch mounted in the unit. The witch is activated by the pi- and in cum, sends a signal to activate the spray gun. While this h.r been taking place, the put has been moving on the conveyor until it k in spraying posltbn at the ume time the spny gun is activated. Thi type of control per. mits us to spny when the put is in position; and we can dctnmine the approximate dupe of the put, and rcdudng w&e and "Irdenance.

H.DOES YOUR PROOUCTION WARRANT AUTQ MATION? 1. High productbn rata 2 Slmnuity of produck S. SImetypeofrmtcr*beiiused. 4. Onlfomity rad qudlty flnisb required.

1. PURCHASE OF EOUIPMENT There is Umkcd amlog infomutiin available on autormtie systems since each unit is designed for standud components to meet the requirements of each puticulu opentbn Each rutomtic mchine is .publed on LII individual orda basis to meet the purieuhr Ipedfiatiom of the customer.

J. GLOSSARY OF AUTOMATIC SPRAY EOUIPMENT TERMS

Autotmtic T a t RMI Spray Unit-A machine used to rpray pmels for hboratov uae in determini number of coats, color. sped of appliation, etc.

h a Sln bmcyor-Urd when the product is hmvy or not df rupporting. P=

P-The distance between one pin of a chain and the other p ia k, bieyck c h l i

ROIIW ~0nn-A painting unit which applies 8 coating to a flat R I ~ with a d e s of rollers. dmilu to i printing

R o u y Spray Machine-Spray gum are mounted on the end of urns ndmting from 8 mtni hub; these a m are a u p d to rotate at the appropriate speed and the spray pnr UT automatially triggered (used on high cpecd conveyors spraying flat work).

Horizontal Reciprocating MachincA painting unit d e signed to effecl a horizontal. or back and forth. spraying stroke on flat or contoumd surfices-usually used with horizontal or floor conveyors

122

GL-RY OF AUTOMATIC SPRAY EQUIPMENT TERMS

rajtic Dr iv rA mech.nkd d n k thrt obWN itS w n h m some other power source. (Example: the w n to operate the pin memory ring ic obrrined from e conveyor’s movement.)

rbn Filammt Conveyor-Widely used in the tanning justry; most nurerials used will not stick to the perlon m”e, looks similar to a a b l e conveyor. Palon Unents are used with light weight products and at r d mom temperatures only.

I Msmory Ring-An electm-mechanical control device 11 uses1 memorydehy principle to control spray guns, unters, conveyors, b c .

I TYPO Convww-Kns mOulItcd on d l t S which NP rt the work and pennits ah citnuhtiornormally used ere excerrive print build-up Is encountered.

Spindle MachinrA painting machine which conveys le

product, on workholderr, prrr the spny gum which are closely controlled; the product m y be caused to mute to Incruse pdnting eflectivenes

Swl Cable Conveyor-Used mostly for sell suppo~ing products such IS plywood, etc.-minimlta paint buildup.

Thrw Way Valve-1s used to operate the air cylinCer of .II automatic spray gun; provides very fast actuation of wrprqrpra

Vutiol Rociproertinp Michine-A pdnting unit similar in design to above, but pmdum an up and down spny s t rokrunul ly used with an overhead conveyor.

Wire M a h Convww-M#de of wire mesh to support the product ud air in forced drying.

:onveyors ilyurothano Belting rd for lightweight products and s h ~ spans. ire Mosh Hides solid suppal to wan snd allom air and spray to is Mrough. Useful for m w o v o n wan and when using :e drying equipmpnt. !whoad Ttolisy (All Styles) s conveyor is used exlensivelywim Bin& Vertical :iprocaling Machines. Wan is suspended f” a hook I can easily be sprayed M both sides wim tw slaggend ay machines. a1 Chain with Cradles lndrically shaped ware can be supponed a1 each end on ;e cradles to b e p wan from rolling. elc.. and pt allow iy coverage.

pjcai Conveyors Supplied by Binb ‘as Slat idely used conveyor lhal wpporls heavier ware. Cross s are Eonslrucled from wood or famed sheet metal.

ppom ware on upright pins that am mounled on cross Is. Air can circulate around and Wneam ware. Usetul en coaling buildup is heavy. Can suppon both lighlweighl Favy ware. rlm Flhmmt ed 10 keep spray from sticking IO conveyor. Resists erioration lrom alms1 all fluids. Withstands oven lwratures lo 250’ F. Used mensively in (he tanning uslry and in spraying of adhesives. Cleaning of filamenl uces the possibility of adhering 10 Ihe back surface of ware.

8k.I Cablo Used tu tarper. Self-suDPating wan such as ~lmood.

biyumthane Belting Wire Mesh

Overhead Trolly Dual Chain wlth Cradles

CrorsSbt Pin

.I. ... - , . . . ... . ,

Perion Filament Steel Cable

123

Complete Finishing Systems

6. Air Make-up

4 9. Washer

70. Bake Oven

124

1. Bulk %tOrD00 @ mgineemd for the productkm job requid. Thy p m

&illtybQLw ofl mCrre mater*ls LI W. lhmesIa8ge tank mnge in size up to lank car cdpadly,

size pwrally being delermined by lb amount of print UJed in your produclicn operation. F" this a m the paint is pumped to a mixing room rvhem ll is thinned to spray pinling -.These syblems meet Federal, Slate and Loul

2. m i n t Circulating S p t o m and Mixing Room This m a mixes and him the paint rasived from the M n g e wppty and circulates ll to the ~t icua spray painting amas as nsebsd. lh location of the Chculating and Ming Room is " a l l y away frod the production u wik araa Mmby meeting saakty and health requimmnts. 3. Spray Booths and Exhaust Sy8toms 'Thew Mitr meel Federal. State and W codes mgerding noise ud air pollutian. Binkt manJpautas a variety of spray bc"I ud aha& models m meet svsry quimmenL 4. Convoyom T h e s e a m ~ w i n g ~ c a l d e v i c 4 t d e s i g n e d t o " the produatrom w opmatim tothe next. Due tothe wide sssu8mnt of pmlucts. Bink mnbwus M custcin engimemdmmyouroperatiaa S. Dry 011 Owns Drying ia the Inuwss ofsvlpaatlng waterurohnnts hg" a soli. 'Ihe Dfy on OraM m i .c"pli his may bed sh.pa and sizes. *pending onthefamd the sosd~ m k dfiedudthe am" olmpter*~ IWUJM. T h e s e ~ n s m b e ~ e d w i t h b a b s l o ~ ~ i n g m h r l a ~ t o ( U u ~ ~ e m . 6. Air Mak04p The Wktim d air mr)wrpsjstenm is impcd" n d d pmductianlossonrmntolemployeedisamnl~pmdud m ) e c t m d u e l o d i n a p o u v w t i l a l i m . u d ~ h e m

euecrraa*wpplVyrt--Inr*d~

a meam of doring large quantities of matefiats Wrm h

and M rpPrWd @ inWnnCe U & d D K .

ot i-"crhus~ otmxk u hirurdour dusts, mbtr. tumaa. poa hating ud M u hilum In heating plank. Einlu un fumish mndd air mkwp mitt fer Wde or outside installatiau M d fU d*trikrtion dKluork If mquirsd. Capacity ranges f" 5.000 chn to 100,000 cfm -ebctric. gar tired 01 seam opmt6d. 7. Botch Ovon Whatmr the applicatim-painl baking. drying, pm-heating or any omer heat proms ol large or multiple produm- batb mns can be fumishad for in and out or push-through operaticnS. pmviding a smooth pcoduCki7 h. Batch Ovens am mailabk as eleclric. gar or steam types and in sizes to rawnmcdate your product. 8. Control k n o l s Cusrwn bulk factcny pro-wired end shop tested control pnels can k fumished in varioos rypeS of enclosures to meet insurance underwriters codes. Central panels am ruppW. W i n g all insbu"n¶atim mqumd. for a mmplele painl finishing system. Panels with programmable " m l s can be fumished with mitaing *ems and 8Cfwrs to indicate ompo" failures in bonderites. mns. apny boom0 u l i r makbups, rvhich mducMtrouMe mooting.

Washing and phosphatizing am used to dean and p m p m mael surfaces. This prevents mrrosim and increases adl" ol applii Uganic coatings to products. washers may hnn hwnhvoto six slag-, depending on you mquimmmb. &th gas or steam operated models am Miiabb. 10. D a b Ovons ~ ~ o v s M M ~ i n f i n i S h i n g y s l e ~ t o b r k e U M m e p m d u d " e c o l t i n g h u ~ a p p l i i i n t h e ~pnyboom. Balm mum mtumi with mul6pk z m , dopending on the baking requimmem. m pru& s gacd (Inirh. h n s lor indou and wtdwr instalktion, *pending QI apace mquimments am Nsilabk. Models M designed l a r M l e r e b c b i c . M a m u g a s ~ ~ .

9. W8ShO?S

Safety Considerations in Paint Application

Introduction This discussion is concerned with a painter's need for safety q u i p ment when applying paints and protective coatings. Binks Bulletin PE--Protective Equipment" h a recently k e n revised and updat- ed. and presents the entire line of safety quipmcnt mukcfed by Binls Manufactunng Company for UTC by painters and applicators of multi-component coatings. 'Ihis bulletin presents rhe protective equipment and appml recommended for different methair of surface preparation and for different types of coating application. Hazards The followinn discussion reviews the different huydr involved in the application of protective coatings which make. protective equipment and apparel ncccsury. Several principal hazards are involved in the applicatton of pnu. Toxicity CM OcNr due to tnhalotion. absorption. or ingestion of the solvents into the bcdy. Also. many coatings which are U-V curable will uusc bums to the skin if not handled properly. There is a r " u m allowable conccnmtion of subsunm that can k inhaled in an eight hour day without danger. The American Confmnce of Govanmmul lndusuial Hygienislr has determined the safe mnanmcion of LIE various subrunces. ud pmeno lhir coacmmtion in teams of pans per million by volume. For m y spray f i g opndonr a s o n d v d paint spray rcspima will pmvide pmcccdoh Standard respirators yx chemical umidger and sepvprc prc-fil- lcn to m p don. mists. ud dust g e m a d by painting opentions. The NIOSH/MSHA approval for lbesc rrrpinms coven mists of paints. Iacqum. and enamels. up to loo0 pans pr million of organic vapoo. They arc .tso appmed fa me in dmu ud mists having a TWA (time weighted avenge) of m less thu, 0.05 milligrams per cubic meter or Iwo million particles pr cubic foot. Rcspinton designed for protection against asberm conumiop- tion arc also available. These may be used by p ~ w l doing asbestos encapsulation. D i i m c p " a which am round in urehm paints. have a low odor lhrcshold. Thlr means that a dangerous k v d of diLo- cyanates can break through tbe charcoal Inside tbe chemical canridge before the painter k able lo smell i t If the paint contains diisocyanaies or the paint vapors ex& the IMX) ppm limit ora chemical cmridge respirator. the painten will need air supplied to them from an outside source. Thus standard paint spny respintors are not recommended for urethane paints or other. paints containing diirocyanates because of their poor warning propenies. This means an air-supplied respirator must k used. Rcwntly. IhUc arc two ouiside air sources: a compressor h a t supplies sir conunu- wsly to rhe air-fed respirator or a large cylinder of compssed air that supplies air to the air-fed respirator as Ihe wwlc~ inhales. Be aware that both cartridge-type and air-supplied respintors have limitations. They must never be used in u w s where there IS less than 19.5% oxygen. where the conuminants arc unknown. are immcdiaicly dangerous to life and health. ?r from

which OF cannot escape without pmpr respiratory protection. Air-supplied respirators offer no protemw if the air supply fails. 'Ibc quality of air used in air-line respintor systems is very impor. um. l@c air contained in a cylinder or supplied by a compressor must k Gnde D air or kucr. as defined in ANSI Standvd 286. I - 1973 orCompreswd Gas Assciation Specification G-7.1. Grrcndy. Grpdc D air shdl not. conuin more than 20 pyls per million wrbon monoxide. 1.W p y u p r million wrbon dioxide. ad 5 milligrdms per cubic meter condensed h y d " s . If the fnsh air which is induced into M oil-las compressor is of this q d i t y (and this should k the CJK unless h e inlet air is grossly ccmuminated). the delivered air will be of qual quality kcause no CCIuminan~~ arc added as the air passes through the compressor. W& oil-lubricated. piston-typ compressors. overheating may pmducc carbon monoride. so routine testing for carbine monor- idc a &e inswllation of a constantly monitoring analyzer is q u i d as well as a high tempennut alarm on Ihc compressor. Alnp know the contents dthe coaling materials being used by referdog 10 Lbc M.lcrll s.tetY Duo Sheets (MSDS) SUP pkd by pur m(CIw s ~ p p l i u . lk l l " l d Limit Values' for yvenl chemical rubslvlm ue pocnlcd in Tabk I. ?be aliphuic solvents. such as mineral Ipirm ad ruphlhr bve a'hw ndcr of toxicity in the m g c of MD 'v p million Ihm may k inhaled in an eight hour day. Stmaw solvents quircd for huvy duty m t i n p . such as the keto& and UIC " a U c rdvmn (toluene and xylene). am much mm toxic, and are listed in Table 1. 'Ibc toxic cffcnr from ovn- cxponm to pain1 solvents IIC presented in Table II. UdOrmamly. LIE most corn" s m g paint solvents such as the MrmdcI Ibc b d chain kmoocs, rrichlacthylene and diace- to^ alcohol LIC phocochuaictlly rwnive. Pam solvents may only coolpin up lo 20% ldum 8 4 x y k 20% methyl isobutyl kc1~1~.a2(#,uichl~yhnc lk noo-rrrcdve solvents include atm. alcohols. the aliphatic ud nrpthcnic hydraubons. lad methyl ethyl ketone. All major paint companies lhrmghout the United Sutcs arc nou active in fOrmUhtIng notbrcrctivc solvenu which will have sol- vem powm and evaporation rates similar IO the currently employed photochcmiully runive solveno. "on-reactive sol- v w m gencnlly COfnpovd of blends of different esiers. .ccwr+. cmpler Ilcohols. and naphnic hydrocarbons. At this point kt's examine five major reguhton. agencies thai in

om way or another affea h e spray fuishinp opention.

EPA Environmental Pmttaioa Agency The EPA's objective is to reduce the a" of paint solvent exlnurted into the atmosphere by industry. They also want to rrduct or eliminate the discharge of ccnain chemicals in waicr. l k r e we five classes of pollumts IhJt EPA controls:

126

m n Monoxide ..-..... CO Sulfur Dioxide ._".._....... SO? Suspended pyliculuc Nitrogen Dioxide .......-.. NO? photochemical Oxidants 0XOronc)

,-o. 502. and NO? are basically products of combustion. Hydmarbon(solvent) emissions fmm finishing opentions are considered photochcmicdly oxidizable and therefore pmdua

Ozone is alleged to impair the function of the lungs Jnd to induce respintory illness. Orone is also reputed to hinder plant p D ~ t h and bring about changes in wildlife habitat. Existing emission regulations and implementation procedures v3r\. widely. However. all future planners in the finishing indus-

should remember that unregulated discharge of organic solvents and pmiculate will not be allowed. In addition. waste water from spray booths will require special treatment 10 remove inor- ganic as well Y organic chemicals. OSHA Oecupatlonal Salet? and Health Administration OSHA's goal is protection of the health of workm. One of OSHA's accomplishments has been an increase in the general Bwarencss of the chemical composition of coatings. Each chcmi- :a1 compound in a given coating must be considered for its par. iiculu impact on the physiology of mn. Possible toxic pmdunr resulting fmm chemical inreramions of the mating with orher agents or ingredients must be considered. New coatings must k bmulatcd with sensiuvity 10 potential shon-tmn ud long-term umuhrive haznrds. Of special concem is h e cumutuive effecl if breathing solvent vapon over extended periods of lime. kquiremcnts for protection of workers exposed (o a known or u ~ p e d l"dous environment mu11 k pur of tbe fd :lese considmuons when commercializing new couings.

lCR4 R n o u m Conservation and Recover?. Ad his am regulates chemical wastes f" the point of generotion 10 IC point of disposal. The following criteria are tbe I;cy elements I classifying a chemical waste as hazardous: !nitability- Rash point less lhan 140 degrees-

(Pensky Mmcns closed cup) orrosi!ity- PH of 2 or less OT 125 or more-Any subswce

exhibiting corrosiveness not orhmviw l i t 4 as hyydous Matcrial~ readily capable of chemical runion such that they prexnt a danger to h u m health and environment

itnction Procedure Toxicity-Related to ability of a chemical waste to r e l e ~ e toxic chemicals in the presence of water.

'

:activity-

,me common paint solvents and solid ingredients are listed as zardous wastes. For t h i h reason. all paint formulations must be refully reviewed as to the composition. classification. and dis- sal of their manufactunng or end-ux residues.

iCA Toxic and Substances Control Act ;CA requires that the new chemical rubswnces be thoroughly ,sed for toxicity. cucinogcnicity. CIC. Chemical manufactum J processors will be required to provide proof that new materi- do not pose significant risks 10 h u m health and the environ-

'nt. T n i s concern arises from the estimates lhat one out of every ir Amencans dies from cancer and thnt90E of all wncm result m cspsure to agents ongtmttng outside the humn body. invat!on on paint systems has evolved through lhc mntinuous relopmcnt of neu chemicals and their associated economics. 127

~ ._

WT Dcpnnment of TranrporuUan DOT h v m tha materids mnsponed on public thoroughfares are a ~ l y packaged and clearly identified. Specific infomu- tion about the murid and its hazard propenies mu1 be on the psckage Lbel and the shipping pap% Cumn; DOT regulafions set the following criteria for hazardous mterials:

Flammable liquids Combustible liquids Poison B Comsivu Flammable solids

DOT NICS prescribe the type. quality and handling of coatings pachgcs. They funher identification of the gcncnl huard prop enics of the material and. depending on interprewtion of other federal and sme laws. a fairly specific identification of drum contents and accident management insuuctions. Thcx costs must also be considered by the coatings chemist. RPmmabillty and Exploslve Limit We ye conmcd with two types of fire hazards: Flammability and the likelihwd of an explosion. Flammability is determined by several mcthodr. but for painters. the "Open Cup" method is most significant This method dercrmines the tcmpenture of the solvent which must be reached in an open container before it will *ucb fm when a flame is applied. Generally. the more volatile the solvenr rhc lower Ihis tempenntre will be before it will catch firr The m n g solvents. such as xylene. toluene. and the ketones ate very votuilc and h f m very flamnublc. 'Ibc likclihwd of any explosion with any solvent is dependent u p Ibc c " m i O n of the solvent vipcns in tbe atmosphere. If the c m x n d o o is UK) low. h u e is ux, link of rhc solvent prcwntto explode If lhis concamtion is 100 high. no explosion will OCCUI because of lack of oxygcn. lkrefore. them are two limits of conanadtion bervecn which explosions m y occur. and cbae are "ed the "bwer Explosive Limit" and the "Upper Explosive Limit". I"s. of come. uc concerned only with the lower explosive limit The h m b i l i t y and explosive limits of various solvents at presented in Table 111. Rae111 Lqidation and Air Pollution Control Considerations The South Coast Air Quality h g e m n t Disuict (SCAQAIDi rad h r EPA agencies. uc conamed with the quantities of pho- l & " d l y reactive solvents h a t may be employed in p i n t s which are sold in mntainm larger thyl one qwn. The recently -d Clean Air Acf now limits the ux of V.O.C.'s (Solvenil in coatings. Check with your local EPA authority for a cumnt list of prnnissiblc formulations. The photochemically reactive solvents. unfonunmly. arc corn. mon strong paint S O I V C I S such Y the yomatics. the bnnch chain ketones. mchlorethylene. and ducctone alcohol. Paint solvents may contain up 10 ?G% tolucnc. 8% xylene. ?OS methyl isobutyl knonc. or 20% uichlorethylcnc. The non-reactive S0IVCI)tS tncludc cstm. alcohols. aliphatic and naphthionic hydrocarbons. and methyl ethyl ketone. All major pint companies lhroughout the United Sute arc nou active in formulating non-reactive solvents which will have rimilu solvent powen and cvapmtion ntcs as the cumntl! employed photochemically mactive solvents. Son-reactire solvents gencnlly are compowd of blends of differeni cster~. pn. nurily acctatcs. COmpkX alcohols. and naphthionic hydmubvnh.

MAXIMUM ALLOWABLE C( Chemical Substance n v *

Ethyl (Ethanol) ...................................... io00 . Isopropyl ................................................. 400

Benzene (Benzol) ......................................... 1 Carbon Tetrachloride (Skin) .......................... 5

Chlorobenze ............................................. 10 Chloroprene .............................................. 10 Chlorotoluene ........................................... 50

Methyl Cellosolve Acetate (Skin) ............... 25 Cyclohexane ........................................... ~ 0 0 Cyclohexanone ........................................... 25 Cyclohexene ............................................. 300

Acetone ..................................................... 750 AlCOhOlS

TABLE I #CENTRAT SS OF SUBSTANCE VAPORS

€ thyhe Dichloride .......................................... 10 Methyl isocyanate (Skin) .............................. 0.02 Methyme Chloride .......................................... 50 Methyl Emyl Ketone (MEK) ........................... 200 Methyl Elhyl Ketone Peroxide (MEKP) ........... 0.2 Memyl Isobutyl Ketone (MIBK) ........................ 50 Perchlomthylene ............................................ 25 Tolutloe CTOluol) ............................................... 50 Toluene Diiswanate ................................. 0.005 TrichlomWene so Turpentine .................... 100 Xylene (Xylol) ................................................. 100

TLv' 1 Chemical Substance

..................................

TABLE II TOXIC EFFECTS FROM OVEREXPOSURE TO CHEMICAL SUBSTANCES

Chemical Substance Effect of Inhalation Acetone ............................................. Irritating to mvcous membranes: choking sensation Alcohol. Ethyl ..................................... Intoxication

Carbon Tetrachloride ......................... Nausea. headache, vomiting: injury to liver (nephritis) Ethylene Dichloride ............................ lnitating to nose; retching; unconsciousness

...

Alcohol. Isopropyl .............................. Intoxication: . headacta Benzene (Benzol) .............................. Injury 10 blood-forming organs. and to hean. liver. kidneys, etc.

Methyl Ethyl Ketone (MEK) ............... Initating to nasal passages: choking sensation Methyl Isobutyl Ketone ( MIBK) ......... Initating lo mucous membranes: choking sensation Nsphtha, V.M .+ P ............................... h a m e : vomiting; muscular twitchii Toluene (Toluol) ................................ Same IS for benzene except llttle damage to bloodforming organs Trichlorethylene ................................. Simiiar to carbon tetrachloride; disturbed hean aaim Turpentine ......................................... Irritating to nose and mmt; headache: vomiting; stomach pains Xylene (Xylol) .................................... Same as ior benzene except little damage to bloobforming organs

. TABLE 111 ~ ~ ~~ ~~

FLASH POINTS AND FLAMMABLE UMrrS OF CHEMICAL SUBSTANCES Chemical Substances Approximate Average Explosive Limits, 7' by Vol.. i

Boiling Point Flash PoinI LEL UEL Range, Deg. F Open Cup, Deg. F (Lower) (Upper) 1

............................................... ...................................... ......................................

................ ............... ...............................

Acetone 132-134 0 2.6 12.8 Alcohol. Butyl 240-245 115 1.5 11.2 Alcohol. Ethyl 173-176 55 3.3 19.0 Alcohol. Isopropyl ; 178-180 53 2.0 12.0 Benzene (Benzol) 174-176 12 1.3 1.1

Cellosolve. Acetate 293-313 117 1.7 - Cyclohexanone 303-313 111 - Cyclohexene 180183 22 - Ethylene Dichlonde 179-186 56 6.2 15.9 Methyl Ethyl Ketone (MEK) 174-176 21 1.8 10.0 Methyl Isobutyl Ketone (MIBK) 237-246 73 1.4 7.5

1 Carbon Terrachloride .......................... 170-172 None Non-flammable ............................. ....................................... I

8.0 i Cyclohexane 179-182 32 1.3 ................................... -

....................................... ............................. i

i -

................. ...........

............................. ..................................... None Non-flammable I

104 6.9 7.5 I 1 i

Tnchlorethane 188.190 None 8.0-10.5 - !

Methylene Chloride 104-105 Mineral Spirits 307-389 Naphtha. V.M.+P. 212-320 45 0.9 6.0 Toluene (Toluol) 230-232 40 1.2 7.1

............................... ..................................

: 1.1.1. Trichloretnane ........................... 165194 None Non-flammable .....................................

...........................................

I : Turpentine 307-347 95 0.8 None . ...................................... Xylene (Xyloll 281-291 81-115 1.1 7.0

GLOSSARY OF TERMS nrrh Point*- the minimum umpeniure at which a liquid gives off vapor within a test vnxl in sufficient con:entration,to form m ignitable mixture with air near the Surfm of he liquid nnmmoble Liquid- any liquid having a flash point below 1mF and having a vapor pressure not exceeding 40 p i n at IOOF. Combustible Liquid- any liquid having a flash p i n t at or above IOOF. Ignition Temperature-the minimum temperature requid 10 initiate or uuse self-susoincd combustion. Lower Explosive Limit ( L W - the minimum concentration of vapor in air or oxypen below which propagation of flame doer not occur on contact with a smmt of ignition. Upper Explosive Limit W E L k the maximum concentration of vapor in air or oxygen above which propagation of flame does not s c u r on Contact with a 10urcc of ignition. nammnblr tExplosivet Range- the range of flammable vapor or ya5-air mixture between the upper and lower flmmble limits. \APOR DEXSITY- the weight of a flammable v q " compared to air. .4i1=l. Vapors with a high density arc more danger- ws and require kncr ventilation because they lend to flow dong the flwr 2nd collcct in low spots. 'flash pin1 is nomi ly an indication of suwcptibiliry to ignitioa. Howew. in finely divided form such Y mist o( s p y . liquids csn be ignited at tempentum klw their flash poinrr. As in mC case of vapors. a minimum concentration of dmpktr must bc pn- sent IO suppon combustion

12Q

TYPES OF RESPIRATORY PROTECTION

Many o p e r a t i o n s a r e performed i n a f u r n i t u r e p l a n t t h a t r e q u i r e r e s p i r a t o r y p ro tec t ion . Among t h e s e are (Upper L e f t ) t h e c l o t h f i l t e r s , f o r p r o t e c t i n g aga ins t suspended s o l i d s l i k e sawdust.

These are n o t recommeded f o r use when spraying so lvent based mat- e r i a l s . Charcoal f i l t e r r e s p i r a t o r s (Upper Right) a r e used with most s o l v e n t based m a t e r i a l s l i k e lacquer . These f i l t e r s must be rep laced when t h e s l i g h t e s t oder starts t o pene t r a t e through. The a i r f ed r e s p i r a t o r (Lower L e f t ) i s requi red when t h e contamin- a t i o n warran ts s p e c i a l p ro t ec t ion . Most coa t ings conta in ing hard-

ening agen t s wi th t h e var ious forms of Isocyanates r e q u i r e t h i s form of p r o t e c t i o n . The A i r Fed Hood (Lower Right) provides t h e s p r a y e r w i t h n o t on ly a f r e s h a i r supply , b u t p ro tec t ion fo r ' h i s

e n t i r e face.

A 1 1 of t h e above devices should be considered i n add i t ion t o t h e spray booth a l r eady i n use. I t 's not on ly t h e moral t h i n g t o do,

I t ' s The Law!

130

Paint Curing By Infrared Catalytic Thermoreactors

New EPA standards for Air Quality Manage- ment are mandating changes in the types of coatings being used as well BS how they are applied. Newer coatings now require higher temperatures to achieve full cure. The standard method of curing industrial coatings has been accomplished by slow open air drying or somewhat faster gas heated convection air ovens. Electric infrared has also been used for curing paints for certain applications. While enhancing the rate of cure, the energy costs become excessive to operate. The introduction of gas fueled infrared catalytic thennoreanon is changing the way industry is curing organic coatings as the following account describes.

WHAT IS INFRARED Infrared is a part of the ELECTROMAGNET- IC SPECTRUM of enem. lnfrsred b an invisi- ble radiant wavelength of energy between 0.07 and 1,OOO microns (a micron is a unit of length equal to O.oooO3937 in. 0.001 mm). It lies just beyond visible light to what b called the red side of the radlant spectrum. Visibk light displays a spectrum of colors from violet to red. The wavelength range of visible light is 0.4 microns on the violet end of the spectrum to 0.7 microns on the red end. All materials are affected by infrared wavelengths. This is identified u ABSORP- TIVITY. and each material hn?, a wavelength range of maximum absorptivity. There are charts available to determine the absorptive wavelength for almost every material. EMISSIVITY is the measure of the infrared wavelength that an infrared device produces. AMPLITUDE is the power that the infrared wavelength is produced and its effective focal distance from the infrared device. Every substance has a speci5c infrared absorption spectrum or wavelength. This wavelength is the one most readily absorbed by that substance. The absorption of this wavelength by the substance increases that substance’s tempetacure. The specific infrared absorption spectrum for an organic coating (paint) a re the wave. lengths between 3 and 10 microns. This is

S U 8 s T R A T E

‘zzwail” mutaw or c8wk4p. )slur “ o g b ~ d p k f p * l ( i l r d b nllrw b n k In- so. or ndidhll pr*lar bm” lol .wb or I ”# .*rr)rEdbtb. 1YI acumhiohdl ~ . m ~ ~ ~ * ( a n r b n t t ~ ~ ~ l p t u . mtwah lam*&nrwa.

precisely the wavelength mge emitted by fhe catalytic thennoreactor. AU paint, varnishes, and industrial finishes contain these organic materials and each of these organic materials readily absorb the infrared emissions in the range generated by the catalytic thermOrepaor.

Substrates, however, do not absorb the infrared emissions a s efficiently in this wavelength range, they reflect them instead. A coating of paint on a substrate is doubly ailected by the infrared wave. The wave &t passes through the coating of the organic paint to the substrate and is then reflected back through the paint. Several benefits result from the physics involved in this process. First, the substrate being coated does not have ‘io be heated to cure the coating. The finish is heated through molecular exitation Srom the infrared wave which causes the coating to cure from the substrate sur- f a n out. A major benefit of this method of curing is the prevention of skinning of the coating’s outer surface and its subsequent “pinholing.”

131

Paint Curing By Infrared Catalytic Themoreactors

New EPA standards for Air Quality Manage- ment are mandating changes in the types of coatings being used as well as how they are applied. Newer coatings now require higher temperatures to achieve full cure. The standard method of curing industrial coatings has been accomplished by slow open air drying or somewhat faster gas heated convection air ovens. Electric infrared has also been used for curing paints for certain applications. While enhancing the rate of cure, the energy costs become excessive to operate. The introduction of gas fueled infrared catalytic thennoreactors is changing the way industry is curing organic coatings as the following account desaibes.

WHAT IS INFRARED Infrared is a part of the ELECI'ROMAGNET- IC SPECTRUM of energy. Intrared is an invisi- ble radiant wavelength of energy between 0.07 and 1,OOO microru (a micron is a unit of length equal to O.oooO3937 ln. 0.001 mm). It lies just beyond visible light to what is called the red side of the radiant spectrum. Visible light displays a spectrum of colors from violet to red. The wavelength xange of visibk light is 0.4 microns on the violet end of the spectrum to 0.7 microns on the red ad All materials are affected by infrared wavelengths. This is identified as ABSORP- TIVITY. and each material has a wavelength range of maximum absorptivity. There are charts available to determine the absorptive wavelength for almost every material. EMlSSIVlTf is the measure of the infrared wavelength that an infrared device pmduces. MlPLlTUDE is the power that the infrared wavelength is produced and its effective focal distance from the infrared device. Every substance has a specific infrared absorption spectrum or wavelength. This wavelength is the one most readily absorbed by that substance. The absorption of this wavelength by the substance increases that substance's temperature. 7he specific infrared absorption spectrum for an organic coating (paint) a re the wavelengths between 3 and 10 microns. This is

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precise& the wavelengfh mnge emitted by the catalytic themoreactor. All paint, varnishes, and 'industrial 5nishes contain these organ- iC"& ' and each of these organic materials readily absorb the infrared emissions in the range generated by the catalytic rtrennorelcw. Substrates, however, do not absorb the infrared emissions as efficiently in this wavelength range, they reflea them instead. A coating of paint on a substrate is doubly affected by the infrared wave. The wave Brst passes through the coating of the organic paint to the substrate and is then reflected back through the paint. Several benefits result from the physics involved in this process. First, the substrate being coated does not have to be heated to cure the coating. The finish is heated through molecular exitation from the infrared wave which causes the coating to cure from the substrate surface out.

A major benefit of this method of curing is the prevention of skinning of the coating's outer surface and its subsequent "pinholing."

natural gar ir Mxed wlIh u* rutmon(hg air ol1* ana(

inside the memmrclorr crliiflic ued ommr 1* w m m hr the alalflis 01ld~llm.

(Pinholing is caused by the fast evaporation of the solvents through the "skinned" Outer surface of the coating.) The curing occurs from the inside out and the outer layer remains fluid while the inner layer of coating proceeds to cure. Solvent is forced from the suhstrate level to the surface of the coating and evaporates through the outer film. When the outer surface has finally cured, all internal solvent has since escaped w d none is left to break through the skinned over outer surface and leave a blemish. Infrared cured finishes have a higher gloss appearance than coatings cored by conventional methods.

WW. I Il lnntCtS CMlbWlM ruciiOn l i b 5 @JCB rlthtp t* IbvmON8dW'S ClblVlk Pld. In &&lk k l U q #~KICII

This is the distinct advantage in furniture finishing, automotive finishing and refinishing, and nul ierous other industrial applications. Cor {entional paint curing methods, such as in a hot air convection wen, the coating film dr ,es from the outside and skins over before internal curing is completed. When. as curing progresses, trapped solvents eventually escape, they must break through the already partially solidified surface, leaving pinholes and craters. It is the presence of these pinholes, in all sizes, even microscopic, that renders a &ish dull and rough. The Merence between drying the surface of the coating and curing the entire Elm is that when the Blm is cured, it can be sanded and rubbed to the desired degree of finish. The surface dried coating is dry to the towh only and may take hours or even days before final cure sets in.

THE CATAWnC THERMOREACTOR The catalytic themoreactor has been d e veloped to generate infrared using natural gas or propane gar in a most etacient manner. The thermoreoctor employs a special catalytic pad to sustain a continuous reaction between the gas fuel and oxygen out of which infrared radiion is anitred.

The thermoreactor is a flameless. catalytic oxidation of the gases used s fuel in the system. Catalytic oxidation will only occur when the proper proportions of oxygen, fuel, and heat are brought together in the presence of the correct catalyst. The thermoreactor system provides the means of producing the appropriate environment for the catalyzed oxidation to occur WXkr Stringent control to be inherently safe. The thermoreactor uses an electric resistance coil inside the catalyst pad to initiate the preheat condition required to raise the catalyst pad temperature above the point of safe catalytic oxidation. Once the internal control veriees that the temperature has been met. the electric resistance coil is turned off and the gas solenoids arc opened to releas? gas fuel Lo the catalytic pad. where it is oxidized. producing the correct wave-

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kngfh of infrved used for nrring. Ihe thennoreactor does not have spark plugs, ignitor points. or open ilsmc within the system lf, for any reason, the temperature of the catalytic pad does drop below the safe operating temperature, the intemal controls will aut* matically shut the unit down. Any power failure will also automatically shut the entire system down. The optimum fuel flow for the thermore'actor is fixed by the inlet orifice diameter and the gas volume supply pressure. The necessary oxygen for combustion is provided by the ambient air drawn through a venturi, along with the incoming gas. Secondary combus tion air is provided by a forced air system which propels the air across the face of the catalyrc pad. The catalytic oxidation reaction is totally safe. In fan, solvent can be squirted into the catalytic pad, when it is operating, without ignition occurring. This is because the odda- tion reaction is so rapid, that the volatile

The thermoreactor is approved by Factory Mutual for use in spray booth curing systems as a separate operating cyck. The interlocks on controls will prevent using the spray booth for both painting and curing at the same time. The advantages of catalytic thennoreaction in fostering good community relations by minimizing air pollution and in reducing insurance costs by virtue of its inherent safety, are readily apparent. -re are, in addition. other advantages relating to installacion and operation costs, and improved product quality. Some of these are: 1. Require minimum venting with fans since

thermoreactors safely oxidize solvent vapors that come in contact with the catalytic disc.

2 . Units do not have to be covered up like quartz tubes o r lights in a spray booth. Any dirt. dust, or overspray which accum- ulates on them is burned off safely.

3. Units can be retrofitted into an already existing spray booth, thus avoiding the need

. for additional space.

ma*erizl is consumtd before It can ailtoignite.

133

4. Versatile controls prwide total operation-

5. Saves space, time, and energy, up to 90% fuel savings compared to bake or convection ovens.

6. The high temperature units can be used in industrial drying painted metal panels, fabrics, leathers, etc.

7. Due to the very narrow range of the infrared radiation, many substrates never get too hot to handle.

8. Rovides proper curing temperature and does not overcure or cause color change totheBlm.

9. Drives off solvents and redicing blushing, solvent popping, and skinning.

10. Highly effecrive on acrylics, enamels. alers, lacquers, polyurethanes, and putties.

11. Reduces risk of dust and dirt contamination because there is minimal air movement, only 10 standard cubic feet per minute per head.

Special high temperature catalytic units are available for industrial application. Selection of these usually is based on results of tests performed with the actual product which evaluate the degree of radiation absorbed as well 8s heat losses due to convection, radiation, and conduction.

Radiation absorbed depends on distance between work surface and themoreactor part shape (hidden areas, etc.). type of coating (resin. solvent amount, etc.).

* Heat loss through convection occurs when cooler air sweeps over a warmer surface, extracting heat from it.

Radiation loss is the heat reflected from the work surface. Conduction loss is where hcat transfers to a colder body (substrate) that is in direct physical contact with the heated body (paint Blm). I t depends on the thickness and nature of the substrate. Thin metallic substrates conduct away less heat than do thick ones because they offer less of a heat risk.

ai flexibility.

I

r

SOME CONSIDERATIONS

The catalytic disc requires an electrical re sistance wire to bring the disc up to temperature before the self-sustaining catalytic reaction takes place. Approximately 10 amps at 120 volts are required for each disc. R e a o Cion temperature is reached in only a few minutes of time. After that, electrical power input is not needed

The units are provided with individual fllten to ensure that clean air for combustion reaches the catalytic surface. Filters should be changed after approximately one month's operating time.

All in aU, the potential benefits of the Cacaly- tic Infrared Curing System are considerable. With today's need for energy conservation and pollution control improvements, I t is heartening to Bnd a produst that answers so many of the concerns of the painting and tlnishing industry. Not only are these systems economical to operate, but they also reduce the time it takes to cure paint and finishes. When in use, Catalytic "hermoreactor Curing Systems are safe to operate and are noted for their long life span. Finally, the versatili*, of these systems in curing various types of coatings is excellent

J spray booths

When selec~ng a spray booth, It k dnuble to check the adety, flrr, insunnce, underwiterr ud kuilding

'B~SpnyBoothrWormmthOSHAandEPAre~- bOns d LR dcslgned exprmlyto bep.Ne p u o a mutahmtherurbungdischugcd to(heum0aphue However, volatile organic compounds in the form of vrpws may not be so xpyued ud attention nuy need to be lpYentocouvlgmfonnuLnon o r o p b d dcktlorr .I "sepuuar" egurpwnt

udm which effect yap uea to determine the type of .prry booth9 thu M .mprpble:

Dry type spray boo* ue chcse that usc a mechanical muru to distribute the dr m-nt e n l y ud PIP vide proper Oltration when rquled. No water is re. puirrd for fflhation HWMT. In so" areas, water may be rquired in the .ru for 5 e protection or clean-up. 1. Blllle booths-an the most fundamental type.

W e plates are used to distribute the flow of air through the spray uea and prevent some of the mild puticles from belng erhPuJted intn the air. They g e n e d y ue wn in applicnrions where m a U spraying operations fake place inmi t tcn t ly md the dlschwged lir doe not have tobe h of paint putid=

rmffincoa b. B.(Beo are designedtopmvide uniform air flow

through the booth and elimlnam some of the *dningputicla

A DRY TYPE SPRAY BOOTHS:

2AdvyuagaofbalUebooh

c ughtinweigtaiflkorlodlngLnaprobaL dSuiuMefaaWithm@lypaof"teri.l e suiuble fa llmlted production where Bemnlly

not more tlun two gauons of paint ue sprayed PI w, vith - d o s e d booths.

t LnrteonofirSulb3 ' n

B ~ o l t 3 o f b a m e ~ C NoawrepLfanaurrpul.cd

L Limited tllpulon of minute plint particles. b. 8." must be stripped when'excess paint

c Dmignedtohpndkonlylimitedprcduction dCmnothrndk9murnols--oprotcs besl with

YEumULtcL

.lovdlyingMtcrLLr. (.%e Rge I 4 tor ulrrmotion.)

I). RLTER TYPE SPRAY B m : Rh+r boMtu pmvlde a mechanical me- of Bltering ?he air by w i n g I t through a form of filter media. "is 6lter also serves u a means of rlistributing the dr 6ov mdy through the spray booth. Obviously. &Y

the 5 k moves the solids. it will gradually build up a mpicrion to the flow of air, requiring change of the 5ltcr medir An air prrssllrr dillercntial gauge (manometer) should be insulled on the side of the b~xith with the pilot tube placed on the intake ride and t he other tube on the exhwn side of the filter brnk to in- d iu t e a pressure Werent id (drop) ac~os.. the filtcr bank. When new filter bank has been installed. a reading should be taken and noted. Thv filters will require replacement when a 25 inch increasc is indicated on the manometer. In some state* require.

-dlcu(tthatapaam dml" milchk bc ~ t o ~ o ! r t h e B l r t o t h e ~ g u l m k d n g ~ lhe spray booth e when- the airnlatqr Qsr below L cemh point. The p m b #eneralIy ~na ide red and m d in incha of rue in a cohunn drua. 1. hhll 8-W m:

PIlnt urestor ffltera ue m u h of a drr-rrurd.nt bu(rd paper and formed into a "honeycomb" am llgurulon. The Sltering action b accomplished by the w i d "back and fh" m m t Mchc air M It passes through the fflter me& cLntri(ug.l fom thmwathe soU& .g.insrthe rmted paper what It nicks. When #praying in one epot the exhuut air m c m the paint pprriclw 0wunUJ most of the Ma uenbccomea flllcd.As the lllm lods up vtithpdnt part~clea and the air m m e n t Uuough the lptg

boothdiminishesud.O"ineh(bQtDtJJ)Ne in L column of run is i n d i d , the ffl(as then "IaCanmL There ue two paper nitem placed In each fflwr frame in back of the apmy booth. The number of h e s in any s p n y booth will be detcrmlned by mze ofthe Illterbank In bock of the spny bXh'Ihr two most common aizes of fflter media awlable a: 1120120 or 1x20~26 md held in p L n by a PrrU f l w d aira pidMdihon8l .iraue.nllrbk "ea UponWkcarmudtheUkImedi.,hrmrdtrry dlta, that which apr mce orthepimla r"cd and duposcd Of 8pscscrikd nUnna.lhe ymnd fflter LI also removed but not disposed of. A n e r fflter 18 then placed in the lutnihme and the old Becord f l l toisnorpLced 0wthen.m Ma. udng ~ p r o c e d " w m t r e s l u t e r ~ ~ ~

A double lmyer of one inch tbick p.& k und. Ody one Lyrr occd k r rp l c td at a time as bulk of paint putides

in& of IUter thiclme5 m CN@t bl the

2. Alldm80 flhor: Andreae fllter b a collapsible or .ccordion paper consuring of two ahceu of heavy firrrrw- dant paper with earugslions of unequal sue whjch

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are .tuched u the cormytlonr. E.ch.rhttt hm mrrOfFeffbnticn8 "I rrl.rtvc to the ocher, both rclaE.uy and hoiizonuUy,muhng.in . w i d Ing prsslec Y) thu the dr s" miles four att- faces before it leaves the IllMr. In doing so, the iticky un-dryed paint strikes the aurface md mlheres, only the rir cleaned of moat solid pant puticles b dischygcdThk ffltermedi. rquires m placrment llso when one tuM inch rbt in water column is lndlutcd Thb type fflm however Lns

Cut6on should be g h n when U& type Btln medi.

higher) or when water bucd paints u e w d be cuge of the poadbUty of ffltcr media-

.bout thrre tlma M the @lit Umun type.

b uscd In .RLI of C O l L N n t hlghhumwty (90% cz

4. *dV~ntrga of 8 flhr trp r p n y booth:

b. Nocompoum%ngofwuerbrrqumd c. l y h t weight in mcrprmmion when floor loodu\g

d Simple erection and hurnllrrion-thus lowenng

a. No w u a rquirtd forranonl of printprreicles.

b a problm.

QaL

FACTOR

H i OveralI mtntion Matcr*L It CUI h d h . Lortnitirlmsb mlcetodr movement. Highhat replacement ne. Time quired for Utter mpiurment cart of Nter repiace. ment in relation to production. h a e o d o r Utter repiaccmenr Lorest i n l u md of spny booth W i t i o n Lowest rhipping Md storw cor; of Utter medk

q u u e foot of Utter medii

mrt per

PAINT ARRESTOR ANDREAE DlSPO

2 1

2

2

3

3

2

1

s

s

3 1 2 3

1 3

3 1

2 1

2 1

3 1

2 8

1 2

2 1

5. Umiutionr of filar spray booths: L Regululy scheduled Ulter replacement k R-

q u i d to keep the spray booth operating 'at top efficiency.

b. Air movement diminishes Y the Nten b e " e med with p l in t

e Produetion time may be interrupted to change

d. "be continuous cost of Nter replacement e. Proper dirposd of Ntn medii is rquirrd. I. Stonge space tequired to keep i sufficient

supply of Nten on hand at dI times. I. h u r e of the pombility of fire extn c m

must be &ken when different types of mterirlr i re being sprayed at one time in the same booth.

Nten

WATER wAsn TYPE SPRAY BOOTHS: The brric principle of opention for rrrndud type water wrrh spray booths is a water " i n nuinuined by a pump providing continuous circulation of vim. A water cumin is maintained by a pump providq a 40 psihead presu~rr and a 10 to 12 psi pressure at the nozzles dong a mdnfold which spnys against 8 de. nector plate producing the rater curuin. There are two methods of wrrhing the paint pigment out of the exhausted air st". Fm by drawing the ur Ulrough

a mntlr"u "ta of mrhg rater, u-.a PJnt putk la La tbr air ue Durbrd out The ne^^ type h, r h e a the Jr ayhg the paint putida mrtc a audden change h diredon of now. Centri. hgd fom (rolute d o n ) flings the solid p.rtida off the nuWn into 1 collecting pu~ Depending on booth deign the dr rill tnvel through a number of ruh chuaba The upper antrifugd ruh cham& k the polnt where most of the pigment Is u p m t e d h m the exhausted air md nwhd down the front mtez cumin Into thc mllscting PM. In the lower rtrb e)Umbcr the b u s t rir must p u r h u g UI.

other unbroken rater curhh. Agdn. scrubbing the rir and the rioient change in the dimtion of the air moves the renuiniq pdnt pigment before the dr prrvr into the exbaust chamber. Through these two actions the .Ir being exhausted is now viztudly free o l d om pigment

The rater k hated (compounded). Thir muses the PJnt putides to coquhte and 0-t on the surface. la thc Wud pump type booths, the p u t i d a ue rLimwd off the top I" umt to time. In the n e , pump booth& the water k compounded so that the putides sink to the bottom of the booth. Pmpnly engineered water wash spny booths i r e the most amptable means of m o v d of punt pigments C" the exhausted air tegudlcss of the type of paint, lk rirO*ty, drying qned or production n k Solvent vapors or fumes will not be m o v e d in any water .I& spny booth. Horncr, water wash spny booths are the mort amptable types of spray booths to di Mth, nre. and building coda. Standud typ water wash spny booths break down into six different styla. "he design configuntions, air nor. water flow. dvanuges and limitations are listed mow:

1. Style "A" Is a low misrrnce booth with a wmtile

137

.. nylamiq d n i p . It rltl-mwt down draft booth rppliationr, high production nus, wious Itqb and width making it able to n t l n r m r l l u r p m d limited rp.rr. It h eonddmd a rrrndud type booth. Air entm at the bottom and receives only two wehcr This design is used In down d n f t water wash booths mort often because of itr limit ed depth. It is dlo urd u the Ntntion back on rpny booth U u t house automatic spindle ma. chines. Water now is 32 gallons per foot of bootfi with a 60 gallon return md a w l f o l d head pressure of 8 to 12 psi. The eliminator section w be designed to be 18"-24"-30"-36"-42" wlde depending on design with UI dr now through the eliminator of 450 to 600 frct per minute per foot of bootb. Note: If 42" eliminator plates are Und. awes doon for removal of plater must be in fmn t md mu.

2 Style "B" is the best type of water wash rpny booth available. It has a combination of the featum that ue found on Styla "A" and "C" m d this combination of double manifolds g ins it the best nltention. It is mommended to use this type booth when spraying zinc chromate or white synthetic materials because of the difficulty in IC. moving these particles This type rpny booth is most often supplied to the F e d d Goremmcnt to meet their requirements; however, the cost is very high. I t has a water now of 24 gallons on the front curtain and 16 gallons on the back curuin p r foot of booth with a 60 glllon return. The water mi- fold height is avuiable from six foot to nine foot depending on the air movement required. The dim- inator vctions can be designed from 18" and in. mad in six inch increments up to 42" openings An air mo\ement of 600 CFM to 2100 CFM per foot of booth can be obtained from design changes

'

CTYLl

3. Style "C" has vuiable or na ib l e engineering design features and w be changed to meet the cyc tomen puticulu needs Low or high veiocity air movement is ivdlable. thmugh booth area. The alr receives four w8shn u It prpes through the spray booth water curLlinr It k the most efficient stand. ud type water wash apny booth designed because It .Lo lncorpontes a bamlllcbacked curuin and is modemte in Cost. It has a ram now of 24 gallons per foot of booth with a 60 gallon return. The eliminator action is vuiable to meet design needc The J r velocity through the eliminator is from 500 CFM to 2,000 CFM per foot of eliminator.

4. Style "E" opentes on the m e principle as the style 'T". This rpny booth is the Urndud caralog. cd rpny booth with a rued design and single back curtain. Thii rpny booth is compo& of standud dze panels therefore it does not require any cw tom enginking. It futures an upper md lower wash chrmber. large capacity collecting pan. dot- ted water Intake p i p to insure sediment free water. circulating water system which forms a con. rturtiy nurhed circuit. removable manifold for ease of mrintenance. hlnged water curtain to allow easy access to the rear of the collecting PM, rr- eerced dn in which inrum complete removal oC water from the pan, MZT door lwted just below the fan for easy mrintenmce. The air meives four w u h a , has a water now 01 24 gallom per foot of booth with i 60 gallon return. an adjustable air velocity of 1050 CFM to 1250 CCM per foot of width of the wash chamber. This unit is the most economical unit to purchase and openle LS far LS efficiency is concerned.

138

0. CONFIGURATIONS AVAILABLE IN WATER WASH SPRAY BOOTHS STANDARD TYPE: 1. Brncb typc or with atended rater pu. 2 Floor type with cross air m o m " 3. Semi down dnlt . (Air entm h m top or booth

and k a v a out one of the sides,) 4. Down dnlt (air enwn from top of booth and

leaves through gratings in the noor). 6. Combination down d n l t r m s r draft.

The nepump booth is a high resistanet booth. The principles of operation k u follows: A high sutic p ~ r e fan. which is located in the spray booth a. b u s t duct, pulis the air under an entninmrnt plate at 1 very bigh velocity. As the high velocity air current is pullrd under the plate. the air movement forces the water ~?fi.n into a smun wbich also nows under the plate. This water ~ e u n increaccr in velocity until it is actullly lifted into a routin; -de or water fd lust behind the entninment plate. Tbe air current must pass through this cylindriellly shaped turblant water column. A t that time the solid punt particles in the air Ureun become trapped within the rater column by the etntrifugll force which is created by the rotating column of air and water. Washing hkes p lan u the air escapes through the water. leaving the palnt particles in solution behind. The ricing alx - water column strikes the eliminator platcr within the spray booth exhaust unit which causes this high velocity mixture to rapidly change dimtlon v v e n l tim- As a ml~, the moisture pmcipltawsaut Md falls back into the tank. Clean air is (hen cxb.usaed through the fan to the atmosphere. The water in this booth k compounded so that the punt particla sink to the bottom. Tbr print solids come coated with an anticouglant wbkb bas been addcd to the rater . and together with the water ue prcripiuted into the w k Drain openings in the nu of the spray booth allow the paint md water mixture to mum to the front of the tank tbroufi a trough. Heavier paint solids nettle to the bottom xbUe lighter particles recirculate until they am broken down md the pigment released. If Iarper amouou of moimtre accumulate on the top bafneq this indicates too much foaming and rquvrS the addition of a heavy weight oil to be added to the water. The critical factor determining the proper operation of a no-pump spray booth is the air velocity. Air velocity is mnwulled by the water level. As the water level lowers in the tank. the distance between the water surface and entrainment plate inereas mult. ing in a change In the air velocity withing the spray. booth. This velocity change or pressure differentkl i s ne& by a p m k which aclivates an automatic water level control valve which maintains the proper level of water in (he tank and proper air velocity to operate the spny booth efficiently. When selecting a no-pump spray booth one must have adqu i t e air make.up available. I f a vacuum mun in the building. the water level control valve will not Yn= the water level mmctiy. If the fan k to be mounted on the roof. the toul sut ic resistance must be mounted for; h m the plenum chamber (or adaptor ring) into the suck. plus the normai IOU through the length of the ruck being u r d .

E. NO-PUMP SPRAY Booin:

bCCESS OOOR oisiniomm PIATE

ENTRAINMENT C U T E

ENTrUlWEhl ?LATE CROflLE

F. ENVIROTECT: The Binks EnviroTeet k a new concept in water-wash spray booths. The principle employs a non-turbulent washing action that thoroughly wets the contaminating particulates which can then be effectively separated bum the air prior In exhausting In the atmosphere. In e o n M with conventional air scrubbing methods, the hviroTect Spray Booth fakes the air from the w k i n g area and moves it through a restricted flm pasrage to form a column of ai? moving smoothly in a straight line. nrm-turbulent p t b of am. Witb aceelenring velocity. thc air h moved t h g b one or more continuous solid & of wuhing liquid wbere the emtaminant particles in tbe air ue i n t k w l y conll*cd and thoroughly wetted by the liquid. Tbe resultant intimately mingied column of air and liquid is then d*ehnged into an elimi- naulr chamber ofmueh m t e r volume. Thii reduces the air velocity and kts the weUed contaminates drop out of t h e . i r B t r r u e Well over 99% ofp.rriculate matter can be removed from rpny booth exhaust air with EnvimTect.

139

A

" O.CONSIDERATION IN SELECTING A WATER WASH SPRAY BOOTH:

1. ?be effkiency of the spny booth CUI be determined or improved by a combination of the following conditions: L In miation to the design the wlcl the mount

of rater (OM) per foot of climlnltor retion bc iq circulated the greater the pvtide elimin. ation

b. The interior design of the eliminator section ia- CIC.YI the eftickncy of putiile movd. M u i - mum plgmenl moral is ndlzd when a l y e r rdume of ak L plrvd t)uougb a nndl m a UId a violent c h g r in rir dimtion wtac place through a curl.fn of rater.

c. Mechanical rpua t ion being uaed ruad or adjustable. b.Ma or dcflnton may be added in the eliminator section to help in puticd

2 The higher the m i s t ~ c e to the movement of iu through the b w t h the better the Ntention. L Dcpnding on design. a "hi mistance" booth

will pmvide better Ntention md are more comp8ct in design. However Uwy lure a hlgher o p n t i n g COSI and require more sophisticated contrul system for eMcient opmtioa

b. Low rcsistmce bwlhs rill not provMe u p o d Ntention as high mustance boothr Howmr thcy m lower in initid cort. lower In oprnting expense and le% complicated to conmi.

3. The mlleeling pan should be at ierct three times the capacity of the pump to minimize the time the water h s to circulate. The front water curtain should extend below the water surface. A weir plrte should be provided to keep mort of the wrchedout pamcles from reaching the back of tbe p m where the suction inWre pipe is located. The weir plate dso facilitates the skimmingoff of the spent panicles bv keeping them up front.

CHE 4. The suction pipe should be louted behind the weir

plate off the bottom of the pan to uwrr a Udi. ment free supply of water. Optfond suction

.U.MN u n be pmvided when requid. The water

140

6. The booths should have a water circulating system with no deadends to tnp sediment. The Wltcr flow rate sbould be easily adjustable to suit the ram circulation requirements,

1 I 6. The maintenance Rquirement of the booth should

be eonridered such u: a. Removable nunifold to simplify the occuiond

danlng and inrpctlon of the upper w d ehmber.

b. Easy aemr should be available to the back of the collecting ~ U I for ene of skimming the entire p a and rrvicing the pump suction pipe.

c. The podtion of the dnin sbould be messed to inrum complete nmovd of the water fmm the collecting pan

d. An .CECO d w r sbould be pmvided below the fan to dlow erry inspection, repair'or replacement of p u p

7. The typ of compound required should be consid- md. This is determined by the style booth, type of m r W spnyed and the materid suppiicr or compound nukers rrcommendationr

8. Om should therefore consider the above listed features and find an efficient booth to meet his mnlr. loul codes. requirements and budget.

KADVANTAGES OF A WATER WASH SPRAY BOOTH:

1. Ampted by mort loal codes rc the best type

2. Most type of mamiJr CUI be rpnyed into water

3. Any production nte can be met.

4. No Nter rephcement. Nter cost, or wasted space

rpny booth available.

wash spny b o o b

for filter storage.

I. LIMITATIONS: 1. "hk water must be compounded in such 8 way

that the spent paint panicles will either float or rink depending on the type booth or materid being U r d .

2merundvd(ypwuaNh~booth.rqubc

3. ~ ~ ~ t b c a ~ h ~ t o t h e ~

4.Htghertnitwcoa 6. Matenab thu m o t be made to float should not bt w e d In Iundard water-wuh spray booths. Hucrials which mate excessin foamIng or will notaettletothe bot" cannot be sprayed in a n e punp booth.

6. The posslblltty of water pollution should be cob sidered.

a " n t . 5 " n ' of-.

dthcwua.

J. DownUndw and Downunder SpriCun Booths: The Binks Downunder Booth is a downdraft spray booth used to paint dl types of motor vehicles. It is avabble in two modeIs-Solid Back md DrhTluu. The downdnft prindpk utilized by the DomUnder is one in which ambient or heated air ia inuoduced and forced through dltns u the top of the booth. The air f l a ova the top of the vehicle, around the si&, and is pulled downwar& thmugh beneath the floor Fate. This downward air now helps to minimize rejects by puhins onrspray to the n m insttad of dong the =hide being sprayed. (In c o n m t , the air D m in a conventional booth goes hum OM end of the booth to the otha.) The DoanUnder SpriCure Booth (anilrble in both

~ m b i n e s t h e ~ d o n n d r n h p r i n t i p k ~ i h c e o m ~ ~ n r r i n g m c ~ o f i n b w e d h a t a s . T h e i n 6 8 . red heaters help save money because heat ia only generatid when the rays strike a solid M a c e . The S p r i C m principle a n llsd be used in conventional CmrSdrnhrpnybOOthS.

- 7 h rith bl-fdd d m ud Solid modcb)

ti. TYPES OF SPRAY BOOTHS: There are many types of spray e for just .bout my type of spray applicatjon @le. All these dinerent types M deypHd to meet the pprriculprmdsof the product The ffltntion needs of the spray booth can be designed into any type of spray booth "i. The ryp of f f l d o n of the exhwn will be delmnLKd by the local codes pertaining (0 the operation of a spray booth in your area Note: for those who arc concemed about air pollution a booth with better f f lmion can dways be selected.

1. &nch tvps ff tou& up Ipny booths: L A BMU spnying area elevated rbwe the floor so

b. Pam which ue tobe sprayed arc dthn arried bto the spray booth manually or on a conveyor.

c. Bench booths are available with 'my of the fol- ' lowing means of fluation or disuibution of the air m m e n t through the booth. (1) B a f L l e P h (2) Distribution Plales. (3) Perforated baffles (for vimous enamels,

mu the spray operua docs not have to noop.

ktcr mdJdhdw5).

i

(4) R t n t u T u t o r ~ (6) -- (s) rn"&upLLarithMen. 0 V m o l a p t u c r m r p M a r . (6) Meul ckuubk (expanded mad) . (0) Metal deurpbk for gtindmg operations. (10) Flockrmnvithdimibutingplatcs.

2 Roar type ot walk4n: L Can be used lor spraying small pana on a turn

table a largehard to mow 1" b. Items to be sprayed may be carried in by the

opaatnraonaconwyar. e The rlr movement k dways directed over the

spray operator from behind carrying away a11 contsmurates.

d Floor type spray booths can have the same m e w of air distribution and Blarion as bench type booth6 (IisIed above). The diredon of the .ir m O n " t thmugh the spray booth can be: (1) cmy- (2) Sard down 6Rh. OJMC paint parricla may

bepllledtmrardtheopemor.) (3) -- (4) UP-

S. Specla1 p ~ r p o ~ sprey booths: L Drytypeforcvpmicmntcriplr. b. V-I type for solvent apnying md cleaning of

purr. e spnyboothaforspnyine~thaIeormde

femw meuL,ue uaulty c"j of ahmi- nu"MinlarnrrL

d DoMldnftwaIerdspraybooth6designcdto Wa Inair h m theceiling ud then be r e m d through -in the floor.This type of insulla- tion is the cleanest rype ud it is widely rued in theM0"indUwy.

e. B a d rowing spray booth. t nllckrprybwth.

rutomobiles. (1) - & Automoth apray booth for the refinishing of

(a) DanUndcr (b) Dovnu&sprlcure

0) Dry- (a) RP. Paint Amstor @)

h Exhaust chambers. brfne or filter type where a &e pmof mom is available for spraying. Exhaust chambers can convert the room into a spray area. These chambers are the back section of StMdard type s p n y booths.

L Flock type lor spraying powdered materials uti- Mng a wire s a n n md dimibuoon platrs.

j. Grinding booths which contains expanded meul C k a n a b k aterr.

L Down draft dry bench booths for vitreous enamels or @hading operations.

1 Canopy booths using brfnes or filters. (Works similar to a steam (able.)

m. Upcinh "4 booth for paint or s t e m cleming n Special Chysler and Ford d a ~ g n s .

.. IL CONSIDERATIONS WHEN SELECTING A SPRAY

BooTn: ?he selection of the proper npiay booth rqubu conddp- .bit thoughr Ihe inttipl in-nt in aspmy booth a n bc returned mmy times over if the correct one hM been vlectcd for your needs. Some of the most Important considerndons ue:

A. SPACE AVAILABLE FOR THE SPRAY BOOTH AND TTS LOCATION: 1. Consideration should k &en M to whm the spny

booth should be located and that the .IC. provided M uyommodDte the compkte spny booth S@ mention should be ghm to thc overhead we-, ak ducts, piping, srmchvnl members, where, how far, and in what direction the crhnun stack muat go to take the exhaust air from the spny booth. Making certain that all access doors can be open is motha essential foccor. The ovenll outside dimensions of most dry type spray booths cm be calculated by lddmg two inches to e.ch side lnd two inches to the back if only the inside dimensions are given These two inches are normally required for the outside hnge. A minimum dear space in front of the booth equal to twice the height of the front end of the booth must be provided for. "his will &e the best poYible operation of the -my booth

2. The mount of air m"cnt ho& the booth, the olpc of tlltntion needed. type of booth "I.

3. The now of producta to and from the spray u e a should be M direct rspoadbk. One m r t d " . nla the m m e n t of the product dlrrab, through the w w booth, w o r h g depth walk

4. It i s ~ u g e o u s t o have a we dnin available in the spray booth f b r . 'Ihb d m of the spray ma, prevent dirt contm!nuh

pennit thc

of the product, ud i.clutrce elem up. -ever. one should check rith I d codes tom U t h b is pcnnldbk.

6. It Is desireable to build the spray booth on a cement curb. This will "isc the accumulation of water under the booth h g e and will .Lso pr- vide a level surface for the erection of the spray booth in addition to extending itc uvful life. This Ir especially important for those who wish to wash down the noor of the booth frrquently.

6. The electrical power md water requirements for the rpny booth opention such u; locrtiun, rvdlability of the proper voltage, current. cycles, phrv and type of d&ncal quipmcnt thrt is go. lng to be required for the spny booth installation.

7. The altitude must be considered in the selection of of the exbust fan lad motor beuuse fans must operate at higher R.PM.'r and in moct UYI Ilu tudc in ex- of 3.600 feet above r r level they Jlo require special motors

B. THE SIZE OF THE SPRAY BOOTH: 1. Thr si20 of the spmy booth is drnrmind by: a. The drc of the lugest object to be rpnyed in.

dud14 UIY necawy product handling quip wnt.

b The number of purr to be in the spray booth at one tiw and the number to be lprrycd at the amr tirm

Uuorrd on each ddr of tbe product to pmvide " i n e a t betreen the object and the lpny booth w.IL Note: 4Vhen u d q rlectmstatk @my quipmnt be sum tbe rpmy gxn h no

, dopr thrn 30 ineba from the mew wdb of &@rqtt-J(h.

c A mini" of two ta t of 8pprr Bovld be

I 4 2

.. d 81. to dght foet mlnhum f o r d *ray opes &I. plus au0w.M for f ~ o w ~ the wort, Li MI i contlnuoui conveyor. If artonutic y a y quipmmt k urd, am adquite rpm for the MehiDc mdI4 to the number of spny lun being urd md the ship of the p a Automrtie r p n y guns lbould a m be dour Uun 2' 6" horn the dde of the booth on rlm kpeed cob wyom lad 3' 6" on hlgh speed conveyom

a %&lent spray station should be provided to v h i n e the rquind Nm bulld-up.

L Spraylng should not begin dowr than 2' 6" I" the conveyor ope*. I! thir is i problem, mxtlbula CM be added.

2. Thr heiphf is d e t e r m i d by: L The highat point of the obwt wbieb k to be

9rayrd plus i mlnimum of two feet cleuance. b. Conveyor ehua rhould be considered and not

extend into the spray mi only the products .nd their work holden Sanituy hook(%) should he provldcd on conveyor trolleys Y) that dirt tUlI'dS CM be provlded.

L PhtfoOmrr sbould be mnddered and pmvided If the spray operator must reach above the pmduct.

3. Chpth should b.: L Deep enough for the work to be endosed by the

rpny booth and i minimum deanrice of two feet from the exhaust vetion in back of the spray booth.

b. The spray opentor should be able to dlad within the Loat line of the rpny booth. (Exapt & bench boo*) .

4. Method of ippllutlon: There are four basic methods of spray application used and each will require its own apecial considention. L ilLatomisatronwUlproducethegrrucamcunt of over-spray and rebound; therefore, this method will repulre the greatest veloctty throughout the spny booth.

b. Airless atomization wlll produce less " p r a y and rebound, therefore, lower air vclocitia may k rued.

c. When elecrronvtic amamion, whether air or rir- ltJs atomization, is king wed, lower air vek~~i- 6es should he considered.

d. True eiecuostatic atomization will produce the least amount of over-spray and too high an air velocity will pull the paint particles past thc product

C. AIR VELOCITY: 1. Tbt air velocity must he high enough to uny dl

solvent vrporr and ovempray ewiy from the punt. lug LICL b w air velocities M muse dangerous conditions md increase m l i n k m c e cost

2. The average velocity for most materids and ippli. cation methods b 125 F I M . (feet per minute) Note: 175 to 200 F.PM. can be obUined whenthe ippliution involm -ic materi.ls or automatic reciprocating michinec

3. Electrostatic spraying q u i r e s " w h i t lower air velocities depending on whether air or drlcrs alee trosutic attraction is kinr u r d or true electro static atomization. (minimum 60 F.P.M.).

4. Thc roluw of a& .ad nlodty for i spray booth exhaust system an be alcuhted by wing the following formub Width I Height (plus the .m of one conveyor openirq) I V d d t y desiml will qual C.FM. of air q u i d throurh the 9 n y booth. Depth 01 the 9 n y b o t h I( not figured & the aleuhtion, Other mndderations ye:

L V e l d t i n thmugh booth genenlly nage from 100 FJX to 200 FSM. and vary with the type of operation taking p h a wlthidthe booth,

(1) Flock 9 n y booths (75 FPM.) (2) True eleetmrLtic rpnylng (90 FSM.) (8) ~ectmNtica t tnc t Ion (6&100 F.P.M)

Auto and huck booth limited pro. duetion (100 FSM.)

(5) Hand spray (125 to 150 FPM.) (6) Auto spray booth for production with

FSM) ('I) Auto 9ny booths for production wlth

dectrosntic (60100 F.P.M.) (8) V u d (150 F P M ) (9) Vitreous enamels (165 to 175 FSM.) (10) Oxinding booth (150 FSM.) (11) D o m d d t bench brush booth (200

to 250 FPM.) (12) Canopy booth minimum of 100 F.PM.

mer rotk yu with 400 to 600 FPM. uouad petimeta of unopy,

b. In Ntnbwtbs becaw of the limited air v e l d - ly thnn~gh the Nta the filter y e a may have

ity through booth. c I b e erl&ted rLm must rko Indude l a p s

accrued ia the system due to static pmrurr as the air nom through the ehrust stack and elbow. I b e computations nude must then he compared to i standud erbiust fan table. (See pages 12 & IS). m u s t ka an be sized by BintC Mfg. CO. if cusk" provides brdc daw: Hemt of mot, locstion of booth, length of stack. number of elborr, md beight of stack above mof.

for ex lmpk

(4)

a& ito&IW 9nY PIIS (125 - 160

b be to Minbhl dqUl& lk TdoC

.

D. THE EXHAUST FAN: Tbc exbust fan k the heut of any -my booth. A fan rheei icb very much ULe i shovel. Every time it molvar It dA-6 the w e quantity of air. In i system the fan will d d y e the m e volume of air

motution rrgardles of the fu~ speed and l i r dendty. Note: disregarding mall effecu of mm. pmsion i t bigh pressure. The M~UR of a fur b N& that &cy will operrte i t the m e efficiency i t dl pointr in i bystem regardless of where It is p i a d .

4 1 / -

n e prfoomrmc~ of a fM i~ hud on three bulc h m . n e f~ mufactumr can provide fm perfoman* tabla md CUIVCI rhlch graphidly shows dI porible combinrtlorrs of C.F.M. and static p i ” C possible for MY given system. There M howwer, a peat m y other considerations which enter into an lndlul. dud fan aeleetion for a system. Themfom before one b able to engjnm a system he sbould dwayr check with tha fan manufacturer to find out what type of exhaust fm should be used. Its size. lad efficiency mquimd for your puticulu application. M a y manufactums rill engineer the system for you U you p m ride than wlth tht nMgply information required to nuke their ulculationz The w h kvel in mort Industrial applicitlons by present methods of measumment ue generdiy accept. able up to 85 declbels depending on condition+ Un. fortunately at p m n t there M not set standuds for rating the noise level of fans In such a ray that it will have m y red vdue. Fan no* may be ittxibuted to m w freton The mod Important ue tbe volume of dr, upicity. borwpown. unbient condltlons, genenl constmetion of the fan and the p-a the .i, mwt follor. However them b a mrconabk ~cumte me.sJrine system av.Uable. It h u been found that In the medium homepower nnge the no& Id b In direct pmpoction to the fan tip speed. n e tip rpecd table below and the previous fm tnbh 011 be wfuI io approximating the noise kvel ratinp This t.M. h O d Y intended to be used u aguidc Md&rrm ab aolutl rdue. Cam” senr md nrprkncr at p m n t

~JM ml futon to condder io the dalgn r b m nok heir m y be IWCIJ.

dp choH

If nobe Iml b a problem then one should d e e t a larger d u s t f~ U pcmihle. A exhaust fa WU pennlt lowering of the fms R.P.M. and thhb WU lower the no& level and s a l provlde ruffieient air move. ment The customer should provide deciblt miding required then Binkr VU drc the fan accordingly. Blowers CM be fumirhed If proper noise level cannot be obtained by the use of the standud vmeuk l fa

E. STATIC PRESSURE Air moving thmugh a duct system under the action of a fan haa tm pressure eomponentJ, atatic pressure and velocity pressure. Static pmsure am in dl directions and is of uniform magnitude in any given chamber of the duct system. Velocity praaure nets in the direction of the flow and can be detected by its effect on a streamer placed in the duct Chamber. Total prearun is the swn of static press- and velocity pressure. Because no in4 openting pressures in spny booth duct systems are low, theu e t u d e is mensured by the vertical distance they cause water to rise. hence the tenn “inches of water column pressure”. An instrument for indicating such p r e s s m is the manometer.

VACUUM

Fig. 1. In its simplest form th. manometer is a U-tub. about hall filled with liquid. wnk bath rnds Of th. tube open. th liquid n n the same height in uch Ion.

!=IO. 2. When pori- tiv’. pressure is applied to one 100. th. liquid is forced down in that leg and up in the other. The dillerence in b ight . ”h,” which is the sum 01 the readings 8- 8nd below Zero, indic8tes nm Pr.uun.

Fig. 3. When 8 vacuum is a p Plied to one tag. the liquid rises in that leg and falls in the other. The difference in height, ”h.” which is the rum 01 t h readings a h and below zero. indicate. lhe amount of vacuum.

c a u e f y of Ihvyer Instruments. Inc.

Tam TIP Jpwd Otclbth fftd PI minute) (approximate)

m-m 60-65

lwoo-120M) 72-79 1m-114MwI 79-85 1m-16MX1 85-91 rm-1m 91- 97

8Mx)-looOO 65- 72 t 1m--20000 97-la3

The manometer can be used to indicate the condition of filters in the exhaust system of a paint spray booth. When the exhaust fan is not operating, static air pressure is the same throughout the sj%m. The manometer indicates this condition by displaying “zero” height of water column. PI in Fig. 4.

144

Fig. 4. ZUO inches of water column

With the exhaust fan operating, 96 in Fig. 5, a negative sIatic pressure is dweloped in the space between fan and fflters because of the resistann the fflters im- pose on the free flow of air through the exhaust duct. This negative static pressure is indicated by the rise in height of water level in one leg of the manometer and the corresponding drop in the other leg. The distance 'D" between water lwek is called the "water mlumn height" and usually is expressed in inches.

Fig. 5. 9" inches of water column

As filters become loaded uith paint spray, their resistance to air flw increases. causing a further dwense in static pressure in the exhaust duct. The manometer displays this condition by a further increase in the dir tanee between water levels in its two legs. A t some predetermined point of manometer "reading', spray booth filters uill be considered "dmy" and should be replaced by clean ones. Clean filten offer the least resistance to air Row. Maximum air Box. in the exhaust duct (indicated by minimum water column height) means maximum air flow through the spray booth, offering greater environmental proteetion to operating personnel and ensuring a higher quality of product finish.

Sct Exhaust Fan Tables on pages 12 61 13.

F. METHOD OF HANDUNQ THE PRODUCE Conddmtlon should be chrn as to how the product

on a conveyor, will It be m overhud type, platfom type, chjn on edge, ete. Will the product have to enter thmugh the wdlr of the spny booth. if SO, how luge does the conveyor opening have to be.

(I) uc to be h.ndled. If tbc pmductr LR to k p l n d

0. STANDARD SPRAY BOOTH va CUSTOM BOOTHS: Not dl spny booths mud be curtom built Mmy UF

rtrndud aWoged items Strndud abloged rpny booths will cat I= and can do the job q u a y P well, in m a t Instances shipping md delivery dates will be better on standard items, as r e U m cost I c g

H. LOCAL CODES: 1. Lwl code requirements or laws ha* been initir.

M by p n c t i d y cities, rmta md inrum- companies reguding spny booths type of rim. tion mquirrd m d insbllation. Check with your loal ruthoritii for these rquhmentc before ordering m y spray booth for their requirements.

2 AL pollution ir being taken more into consideration these days, therefore, the exhaust discharged must be considered more imporhnt than befon.

3. N o h pollution an violate the rights of other per. sons and the courts will protect thsc rights. There. fore a & e noise In a plant my mu= adjacent prkrtc propnty OW- to Institute legd action for nUef or put I stop to the ex& no&.

4. Tbc National Fke P r u W o a m t i o n Inter- lutlond hr I d e w mgulrtion booklet which a m a t b e m a t frequent CUI= of I L a I n a r p n y au and fire rrlul.tioar mquM In most cities and statu You m y send to @e IoUOring a d d m if you rLh to procure thL booklet.

N a t i d Fire Pmrcerian A6a" . . Ana.: Subrriptions Department

B.tte& Park WCY, "9

Ask for booklet NFPA No. 33 Spny FWi.

1. ELECTRIC WIRING. LIGHTING FIXTURES AND SAFETY CONTROLS: Adequate lighting in the spray booth is essential in tunring out quality work. The operator must be able to nee what and how he is spraying or that automatic equipment is functioning properly. The type of lighting, lightin? controls. and electric wiring that one chooses is dependent on local safety codes and person- al preference. Some t j p s of lighting a d a b l e for consideration are listed below: 1. For work tha t is being done deep in the spray

booth, top lighting as well ps side lighting should be considered.

2 In small booths where the spray opentors stand at the open end of the booth. angle type lights are SUI- dcient.

3. The trpe of lieht fntures which are atailable can be either incandescent or fluorescent and fall into three different groups:

('Is0 21 55 2285 1 la 1313 1 4 P 1641 1750 1 8 9 1914 1969 2023 2078 21 M 2297 2406 841 942

t o n 1279 1346 le1

10% lo00 1100 1125 1176 1200 1M 1300 1350 1376 1400 1400

18 . 18 18 24 24 24 24 24 24 24 24 24 24 24 24 24 34 34 34 34 34 34 42 42 42 42 42 42 42 42 42 42 42

4a

11%. 11% 11%

18M 18% 10% 18% 18H 10% 18% 18% 18M le* 18% 18% 18H 23 23 23 23 23 23 24 24 24 24 24 24 24 24 24 24 24 23%

6 1 8 1 6 1 4 1 4 1 4 1 4 1 4 2 4 2 4 2 4 2 4 2 4 2 4 3 4 s 4 3 4 2 4 2

: I : 4 s 4 s 6 s 6 2

,6 ' 2 8 2 8 2 8 2 6 2

201165 3200 201129 1020 201129 uoo 205147 3632 205147 6441 205148 6B76 205146 M50 205148 W.5 205149 9119 205149 9339 205119 9659 205149 0024 205149 10101 205149 1073S 205149 11260 205149 llm

205120 1- 205120 13395 205120 15315 xC5121 18167 2051s 19140 2051s 21060 20- lOBs0 20-5154 1- 2051% 21W 2051% 22300 205167 23000 20.5157 23MO 205157 2- 2Ml67 zswo m 1 5 7 zo 205157 27250 205157 my) 20-3460 41250

74 254) m.5 3500 80.3 5m 87 4513 70 6677 72 a13 ?6 7422 n MIDC 79 8579 80 0857 81 91 54 81 Ws4 82 9118 63 10285 M (OW a 1 1 m 72 lwQQ 78 11726 79 13892 83 17015 M 1802# n 20057 m 20403 84 1 m m 203#) n 20700

08 PJOO W PJSO 90 2429 01 254w 91 25950 92 26(%

01 Jo8w

67 a m

74 16%

80.3 3Uo M JogD 71 485 72.5 6638 78.5 mzs

m.6 31%

n.5 7- 79.5 M.5 6570 81.6 11868 81.5 9161 82.5 9456 63 1- M 1w13 06 11182 72 7 w 75.6 1w 79 13080 63 16380 65 17433 67 1e531 88 27000 M 1m00 a 19300 67 l@MO 87 2ww a4 21450 W ps#) W am m 2u00 92 2w0 94

91 2 4 m

74 78.5 80.3 M 71.5 73 77 78.5 79.5

81.5 81.5 82.5 03.5 M.5

71 '15 70 63 85 67

84 85 67 87 68 W 80 91 91 92 M

m.5

m.5

m

. - . D " k of rouM bnl ol Ilm hnon #"A" umb. hkm 10% (rwn(aH.l. bdt

-1 - .nd&lks Englnnling a* bMlumn.

mo.. PmdmiIyol mom walls .nd Dlh. DBA .Dn raw -%uH 1YI. LwLd mnWW 6MI ramd bnl. hrtJ*d .ourd ln" m y b. nqund%%

8 - on 1 7 9 RPM mc(a qmd.

with the above to &ut off the .Ir to the q r a y gun when the exhaust Ntcr unit becoms dMy and the m o u n t of ur being moved is su!fidently d u d .

7. A water sprinlrler. urbon dioxide or dum system may be r e q u i d to tum whenever the tempntw in the spny booth a m rises above a d n point k a u v of a fue being p m n t .

J. AIR MAE-UP OR REPLACEMENT: An air make-up or mpiafcment syNm is important because of the l y e roiume of air exluurtcd from

two or more complete d u n g s nny hour. Under such conditions in winter, the (PRY m a may become cold and uncomfortable, nnLh problems an uicc be cause of spraying with cold n u W s on cold pro. ducts in cold air. An air make up system will provide even tpmpentum md c lan Nteml ur .I wall as to a r e proper booth pnionnu~ce.

rp-j boo?hs This ahaurt L d n c k n t to p r q d ~ f c

1. The air which Is mpimd k heated and Nted be. fore It enters the spny booth .RL

2 T h systems should be designed to provide a r r p l u r w n t of air Kcording to the volume which

146

k,

(h.

113

1 /4 112 3/4

112 3/4 1 1H 2 3 3 3 3 3 5 5 5

1H 2 3 5 7% 7% 7% 5 5 5 5 7% 7% 7% m 0 0

0

12

18 18 18

24 24 24 24 24 24 24 24 24 24 24 24 24 34 34 34 34 34 34 42 42 42 42 42 42 42 42 42 42 42 48

in U N D U

74 78.5 00.3

72 73.5 n.5 m 00 81 62 62 a 5 8 . 5 84.5 ms

ms 74

83 84.5 87

84 86 87 87 M Lo

91

92 91

m

m

m

4815 5- 6851 72n 767Q eE4 8426 9131 9796

1043s

13901 15325 1 m 4 215#) 1- 162550 l(Ws0 1- lM30 20100 21350 psoo P l W z37m 32250

n 795 m.5 81.5 K K N 84 85 87

K.5 84 87 86 84 m 86 87 m 19

.m e1 01 92

93

81 K K 62.5 83.5 845 85.5 87

84 88.5

88

84 84.5 8!i w M.5 Lo

91 91

93

m

4030 4545 uoo 6867 7971 MS3

10100

12950 I4100 lsOs0 1 I O lw00 I 9750 xu50 27254

82.5 (13 84 85 85.5 87

06

84 85.5 M M 89 W W 92

84.5 85. 86 07

m

85 86 a75 89 80.5 w 92

%z2 ..u (*I 0 - m m m 70

125 125 125 125 130 130 130 130 130 130 135 135 135 260 280 260 260 275 275 310 560 360 560 360 3m 3m 370 370 360 380 400

How to a b exhauat hnr tor rpny bootha. Eumple: l k v type IDRV booth l i l h inside dimraiow 1 5 wick bv 7' hugh. IBooth a p r h 60.. not enmr me alsu1ation.l kltiolv 15' a 7'. lhich coma 10 105 q. h. or me Moth hce a m . Multiply the fmm area bv the HIociIy dnirw. ( N m r lm tk.n 100 FPM. @enmllv 125 l o ~ F P M . l F o r r ( l e e M m o k , m r r r n t a n a i r f l ~ r ( l r o u g h f M bwth of 125 FPM. Our 105 Iq. II. I125 FPM4urla 13.125 CFM.

Ennr the fan Uble above under the Y" mtic oreswre column. The nureal CFM ~ r * a t e r 1h.n w r ulculation is 13.892 CFM. Thia i s fan Model 304307. Diwdinp 13.892 CFM by 105 a. 11. b o o t h f K t

uul g i n r 132 FPM. Model JWm? utidim our minimvm 125 CPM r**rinmnt. Checking 10 m il a Ian with 1 . p 00.city will w k , w m ( t u 1 1an Model -305 ka a CFM rating of 11.726 CFM. Diiding mi# by 10s a. h. m gn 112 FPM. Thia is less man the desimd nlociw thmugh tk. booth. Model 501305 wit not be nt*C8y. In Wl.ning a fan for a *om & m a y Moth. m a l other @le. mm, of amIic Iwismncc must be ukm into conridnacm Vow Oinks rwmmmtive will gladly .nw YOU m the ulcu1.iton 01 1h.Q r.u~uncu.

bu been exhausted and dm h a t this .i, to r designated tempnture and humidity. The air mry be heated by one of the following mew:

b. Hot water supply. c. Indirect oil r i d . d. Dimtgrrfired.

. . c. Indirect gas !id. L Elecuic.

Note: Direct fired means the products of combustion enter the air supply. LBTU of flame hen1 isqud to I-BTU 01 heat in a direct f k d system. Indirect fid is only about 70% u efficient.

a. s(runruppiy.

3. I n a c l o d system such as an aslomobile booth air mate up syuem should be d t s i d to providt a dighUy pealei or balanced volume of incoming air than is being exhiusled. Ths will provide a positive pressurr in the spray y e a thus helping l o keep dust and din Imm mlering. Note: If the airmakc. up is too p a t it could possibly cause punt 10 p a s into the room or tuck lord the filten

4. A purge y d e should be incorporated inlo a closed spray y e a if posiblc. This will insure that Ihc air is clean before my spraying opention ern bcpin.

I(. QUOTATION REQUESTS: Quotation request forms u1 available for rrqwsting

r h e m a spny booth 01 lIr NPPlY P ~ O u t i O ~ Tbae forms LR nriiable by d i l y for Form N u m b 0.256 for s p y boothr ud 0-(NR for air NPPb ry-

IV. MAINTENANCE ~ h c nuintenan- 01 a rpny booth k i m p o m t if OM wmm to receive tbe lull benefits fmm bk inravnent Tbe fouowing list coven tbe mort Important poinu:

1. QcuJiness k important to cut down tbe paulbili- ty of fire I" acajve materid build-up.

2 hoper mrintenurcr will help produce i hi@ qudi- iy llnLh by minimizing din eontamloation.

3. Water wash rpny booths require the water to ham compounds added at regular l a m 4 lo that the m n r p n y purida can be removed urd to p m n t nut. The oDmpounds uuy tbe particles to noat to tbe surface in pump type booths md in n e p w p booths the puticla LIC caused to slnk. Oil must be applied also in nopump booths to keep down the foaming action, rrpecklly wben water i s found on the upper b d f k Cutu" a u l d check with hlr compound manufactums dm to try and find i cumpound that will not foam LI much.

4. Roper water levcis must be maintained either m m udly or automatidy to keep the rpny bwtb operating at peak eKdency.

5. Filter spny boo& require rmintemce wherever the Nter bank or media becomes co coinrd with 0rrr.rpwed partidm that It rsducrr the lir m o m ment thruugb tbe rpny book DMy flltm B w l d k WW md mnmad hom the pmnirrd ~ l l ~ y p l d In anpmor air t&ht cap W D m

6. B.mc booths require the slpplng of tbe hma and abaut stack priodk.ur to pmmt the pori- bPIty of &.

7. Srrlpabk or pcl-rrry W n g whkb un be pu. m d sprayed on tbe rpny boo& rp1 belp in

Mintaining the ddineai of tbr rpny M d a h provide tbe ene of drkd paint remmal. A helpful hint In working wltb rtripable coat+ k to YIC two inch " k i n g tape on all r a m s befar ap. plying tbe coatin& Thk mctbod p m m u tbe r&ihble coating bom getting Into tbe - and dto ddd in pulling tbe coating free when It be. COma IIw.cpuy to dean the booth. Nolr: Do Not UI rtripablc mtmp on the h t e d s u h 01 r p v booths bcclur If it pulls free it will plug the water pump intake porh or plug n o t r l a

8. Cbeck cxhruu fan lnd ̂ V" belt tmdon. L Fan m d motor Bould be able to wm d l y by

hand. b. Fan bearinp are eithet fuUy d e d or equipped with a puc cup, Um. pcunny 1Whovn

c Fan b h d n hould be checked and lnrpccrcd PcriOdiUUy for arrnivc paint depcxlts wbicb wU decrease effkkncy and may unbr*nce tbe blade musing exea i re ribntion and podbie b n k w Never strike the fan blades for elem iru PUTOU. Jwayr use i mipper to,dean

of opntioa .

tbem. (Curtion: do not UIC I stripper which .trrdu dlnnlnum)

@. CbrrL drcek motors L For the flnt boun of opcntlon d e c k moton

OeCaionJly. Trwble wU be indiuted by bi@ openting tempmtura or nobe h L

b. BJI bearing moton qulpped with a grease flt. Ung wlll rqulre pas ing ippmrlmately o n e per month If opented continuously. If they have OU wells tbcn tbey should be inspected dally and oUed U required.

10. Cbeck (be medoad heater eiemenk In tbe w e t . k dvtn Heater eiemenk ue drays -ped wltb mpcn rating& T h e lhould mad ippmxi. m t d y 5 n to flftccn percent higher than tbe full rating of tbe motor i t opetating voltage. "his fuu load nting k -ped on tbe motor m e piat. md dto indicated in unperrc Tm high i rating of beater elements pies no pmtcaion Too low a nt ing uurer the ~Lvtll to tbmw out dunng start. inf periods or In hot wdlwr .

11. Always start one motor at a time beginning with the fan motor 5rst.

12 Cb& circulating pump unit .r follmr: L "be pump unit sbould turn nrily by hand. If It

d a not. tbe packing @and nuy be too tight. or the motor coupling out of digment.

b. A slight drlpplng of 5esb ritm Bould conu f" tba pocking gland wtQe th pump hoper. ath& Ult d a not. th pack@ gland b tm

pump rrl to Lo md nuy maod the &ator. ugbt Md rp1 wt the pump du& alldng the

V. ACCESSORIES A. Tu- foc upparing the product whili k ir k

he CMd, th. cvpc of "tlblri available an 11 follon: l. NortMtlngforU@t lordt, d wand no l r p 2 Hemyduty np to 500 lsrlolds .Ither b u mount.

3. blotor dmcn tumtrblr to turn the pmductr auk-

4. h u m . l * Ult hunbbla tops lor picking up

6. Tum bble tops will vary In .Lc f" 10" to 42"

darltbkp

mUanY, lpad b djurtrblc.

bcrry ltemc a p d t y 1OOO Ibr

depdlng ctn requimnents

B. ORAFT GAUGES For the cllcethc meanmmcnt of Jr prroavc differ. ratid- ihk indiarr. when the rpny b w t b !litem B w l d be m p W

C. FILTER DOORS Nter doom rill p m m t dust and dirt bom entenng tbe l pny uu and yet p m i d e rumcknt air r rphce ment .ad dWtlbution

D. S P R h BOOTH SCRAPERS: Spny booth unpm .R mmctcd of i aon-femur, Eon rpuklng n u a for tbe r n p i w of tbe walls of "Y booth.

148

LcoNvEToRsyFIEM8. ~ s m a n s u e d a l g n d f a ~ t h c w o r k rhieh 1, to be painted to uld fnmthe .ary.rrr, cut ~ d a m o n m u a k l ~ a p

F. SPRAY GUN RACK AND SHHELF: Tht spray gun rack ud shelf Is mounted h i d e the rpny boothso hLIh.2 opvnun MEtore SPraYw alps uld other ne“y itmrs

Float boxes ue designed to ense and maintainurcu- me wuer h l in the splay boob wnter pan.

nK action eaten is placed on the water wash spiay booth pump Intake and prevrnu any large lumps of paint residue from entering the pump causing possrble damage or plugging n d e s .

ln*rloclrS are additiond safety devices which a n k added Into the spray booth system to do the following 1. Air solenoid nrlm to cut off the compressed .h

2. Air Werentid switches to sew when a V.MM IS k i n g drawn behind a fflter bank. The ezhoust fan be cut oE and not turn on unffl tht fflW bank hrs been de&

3. ElCClrostatic spray gun Interlock is placed In the system where no power is supplied to the S P n Y gun una the r p n y booths e- fan Is in opauloh

J. SLUDGEFILTER:

G. ROATBOXES:

H. SUCTION SCREEN:

L INTERLDCKS:

supply into the spny booth

Sludgti l l~n are -ling acreem whichhave antio 01 50 gallons per minute bluatjon abm per atpan foot of surface area. At the other end (here is a high p r e m blow-off which b l w the spent paint particles into 8 mnuimr.

VI. REGULATlNG CODES FOR PAINT SPRAY BOOTHS: Vaious mgulPtoy agencies claim RsponrjbiUty for dr terminvlg the safety .nd le- of ppint spray f.dlities. 1.e. spray booths, enclosures .nd spray rooms In order to properly advise you and your customers of (hex agencies and their functions we have listnl the primyr ones h m : Underwri ters Lab IUU-UL is not a government agency, but an enforcibie code. Testing is for safety bum an elecfziicnl fire and sm& mdpoint. A spray booth component, i.e. motor o r light fixture, may be UL apprwed. but spray booths uhmselns are not. Factory Mutual IFMI-h hdustrid underwriter using

oun ~ r p c o r i e s to test, evaluate Md appron q u i p men1 inslnlled in their member plants (applies equally to FIA. or LRJ.). Occupational Safety and Health Adminiitration IOSHA)-This government agency is concerned with safety inside the plant, ud the rrgululon regarding the use of nYMlable or mmbustlble “ids. Marc of this regulation is based on ANSIINFPA 33 standard (see below).

ANSUNFPA 33-The industr). bible from which most codes on painting operations a re written. Provides recommendations only and is not enlorcible. The in-

5ucnceofthirbulktlnonothsmdesnukeItofgreu bnpnuncc. EnvlrmmanUI Protmtlon Agency IEPAI-A federal agency Involved WIUI the poUution ot outside a&. Them ue no EPA mgulafionr thu apply to solid conurninants b u m paint spray booths. There am EPA regulations on solvents. Their guidelines are intended for very heavy concenfntions of poUutanm. State and Munlclpal Government#-There are d e pvrments ud agencies u all lmlr of gmmment rtru

wray facilities. These Include Industrial commissions. departmenu of health, sanitation and fire depnnmentr. You will and that the great majority of these are lpounded In NFPA 33. The followlng list of spray booth regulations is taken hom NFPA 33.Tnese am the regulations most frequently encountered. 1. Chapter 3, Paragraph &A clear space of not less hn S’LY on all sides of a spqv booth shpll be kept bee of mmge or combunfble construction.

2 Chapter 3, Paragraph 9-When spray areas are lighted through glvs panels only tired light units shall be used. Panels will isolate light from spray

3. Chapter 3, Paragraph 10, (h)-vlslble gauges; or audlble nLrms. orprrosurr .cti~teddevice~rhp~l be lnstauedtoirwve the required air n1Oclty.

C Ch.pter 4, P.n(p.ph 72-The space within 3’0‘ in .U direcUon~ d” OPmingothcruM an open hunt rhrll k COnSldacdMCks 1,DivWonZ

5, ch.pta 4, P-h 72 (a)-= CLU 1, Dhirion 2 u t a e n e n d . from the open face of a booth 5’0‘. If the exhaust fan 16 interlocked with the spray qulpmenl

6. chpta 4, ppR(p.ph 12 @&nK Clprs 1. Division 2 M “ b h o m t h t open face of a booth IO’K If the exhaust fan ls not inlerlocked with the spray -Mm=nt.

7. Chapter 4, Paragraph 9-Portable electric.Iamps ahall not k used in any sprafig area during sprny OpoPioM.

8. Chapter 6, Paragraph 5-2.1-Ventilation for con. n n t i o d spny operafions shall prwide an avenge nloaty of not ka than 100 FPM. Electrostatic operations shall provide M average velocio. of not ley hn 60 FPM o n r the open lace or QDSS section of the booth dunng spray opentions.

9. Chapter 5, Paragraph 67-Individual spray booths shall be SePamtely ducted l o the building exterior.

10. Chapter 5, Paragraph ii-The exhaust durc discharge point shall be not less than 6‘0’ from any combwtible exterior wall or roof.

11. Chapter 7, Paragraph I-Spray ares shall be prB t e d with an w p d automatic lue eninguishing system (No1 a Binh responsibility).

12. Chapter 8. Paragraph I-Spraying shall not be con d u d outside of p ” m n e d spraying area.

13. Chapter 8. Paragraph 3-All spray areas shall hc kept Iree from the accumulation of combustible deposits.

14. Chapter 8. Paragraph 9-Spray booths shall nwt be alternately used lor different types of caring ma.

ye invohrcd in coda, replations, and appmvnl of paint

M

149

cakh,rhactheircombinrconnuykcaductnW rponwmwignition,unlas.Udq”dtheM wd “i.l ue m o v e d &om the booth md exhaust ducts prior to spraying with the second. Eumplea of dangermu combhations ue: L Deposita of lacquers conuinlng nitrocellulose

combined with hishes conUlning drying o h , auch as varnished, oil based stains, air dry aumels, ud primus.

b. Blemhing compounds bued on hydrogzn paox- ide. hypochlorites, perchlorates. or other ox& dizing compounds combined with my organic

15. Chapter 114-AutomobUe &nbhing spray booths w enclomucs. otherwise installed md nulnt.imd In

conformity with NFPA stydardJ, may Jtermtely be wd for drying with ponable electrical in&ared drying apparatus only when conforming with the foUOving: L Interior (especially h r s ) of spray enclosures

shall be kept &ee of “ p r a y &posits. b. During spray operations. the drying apparatus

a d electrical ronnections and wiring thereto shall not be located within the spray enclosure nor in any other location where spray midue nuy be deposited,

E. Spraying sppupars, drying .pp.~lr. ud vente lptins s~nan of w a y enclonvc shall be quipped with ruiuble interlocks so m g e d uut: (1) Spraying -01 OEM while diying a p p u ,

tus b Inside m y endoam (2) Spray esclosure will be purged of spray

vapors for a period of not less t h m (3) minutes before drying 8pp.rrtus can be cmrgized

(3) l W h t i n g s~nan d maintain a d e umc- sphere within the mcloavt Sptnethe myins P - d d r y i n g s p F ” d a l “ & d l y shut off in the event of Wure of the ven- synan

A 4 5 In general, eledcal equipment b not prmlaed h i d e m y spray booth, in erh.usc arek, in the

a rpny operation, nor in the direc~ puh of spny.

A 4 7 Unless separated by p.nitions. the m a within cenain distances of the Iumrdw spray are% ck pending on the m g e m e n t is considered Dm- sion 2. Within this distance, electric &ps mlul be enclosed to prwent hot particks &om rpuu\p on combustible materials.

A-SZ.1 Spray Booths-When spray booths are pmnad with adequate ventilation, booths m y be LO I* cued with respect to the source of theirrmhup air replacement thu air in the entire sp.rr &out the booth moves toward spray booth e h u d “dead air pockets” are “ised. -re spraying ir conducted inside a spray booth using conventional spray equipment m avenge air velocity of approximately 100 linear FPM should contain overspray. The ventilating inn capacity in CFM must be 100 r e t per minute times the total area of booth openings, Le. frond. ma, connyor openings, etc, in spuvc fcer

---

ent-ained air of an exhaust qsmn

A lower ntc of uhuurventllrcion may be em- P l a y e d b W .pnying.Gunnlly,antl of e lhun of approximately 60 linear feet per minute will keep the atmosphere below the e@& llmlta

NFFA No. 70 (Nlaod Ekccrial code) Chrpta 616-2

L CIMS 1, Division 1 loutiow--The Interiors of Spray booths and their exhaust ducrs; dl space wlthin 20 feet horizonrally in any direction 8nd 10 feet ve!tiuUy &om spraying operations not conducted vlthin spray booths.

b. CLUS 1, Dhrision 2 lOutions-(See i t em 5 & 6).

VII. OF INTEREST TO USERS AND SALES PERSONNEL: A. CONCERNING EFflClENClES OF BlNKS SPRAY

BOOTHS THE MUOWING ORDER CAN BE EXTABUSHED: 1. ENVlROTECT WATER WASH SPRAY BOOTH

L Moat edlcient and expensive standard cstalog

E. hn twa te rcuah l s s t amkd . d Dyna Unit is fabricated in welded sections

which rqulres le% d o n time in the field. e. Specill dowmhft models are aMilable. f. A hrsh production, lugh cpppeiry washer.

booth b. opaucs u 2r to 4 . r W C pressure.

2. NOPUMP WATER WASH SPRAY BOOTH 8. ope~U(‘to416nZtiCprrraue. b. Specid wuhen ue available from 600 CFM

P e r w fOnI0 uoo WfL L Dyna Unit is fabricated in welded sections

rNch mpim less d o n (bm in the field. d. 8ped.l QandRn models are N.ilrblt.

3. WATER WASH SPRAY BOOTHS WIM SNLE A, B, C. OR E PUMP TYPE DYNAPREClPITOR UHITS .: Expense varies by style of 4nr Unit, but is

\urullylasthntheEnvimtmud NOPUMP booths.

b. Reskunee varies by style of Dyna Unit, but a n be su(ed to range &om .B” to 1.3” rtaric P==Jn.

(1) ‘A’ Style-600 to ZOO0 CFMlh. This Dylrp Unit hrr a low k n l air intak. This feantre k MA for doamdnit booth opplimion~.

0) ‘B Style-8000-1800 CFMlft. The most emcient md expensive of these washers. ’IWi Dym Unit has (2) nuniloldr for ddi- t i d wrrhrng and e5dency.

(3) ‘C‘ Style-BOO-2000 CFMlft. Has a high level air intake. Ideal for special height spny boothr. Our mon vt lyr ie pumptype unit

(4) ‘E’ Style-BOO-1250 CFMlft. Our most POP* - dnh, PumPtypc Dynn Unit. Catdog itsh Economid in aydprd form.

.

CLinulfeetaprciries

4. AzfioMorrcrE SPRAY BOOTHS L DOWNUNDERSPRAY Boonis

Air ir inOodUCed ud forced through filters at the top of the boo& The air flows ow the vehicle. mund the sides 8nd is pulled downward through the Blter be

IS0

neath the @atln& WWI WY d " f t method the ownpray hu less opporh~nlty to adhere mdqdthednbh.

Same .wOar principle u Ute Downunder spray booth and the booth is quipped with heaters Smtegidy pOrmoned for proper curing of the coating. special inWlOcka are pmrndcd fm Ute .pnyine Ud wirur eudca.

Note: The autoomo(ivc w&m mentioned rbon ue aeldom encountered omside the auto ~~USIXY

b. DOWNUNDER SPRACURE BOUll@

md are sired md priczdmeaeh ¶pciuarion. e. ~,Fi l taTYPeSPnYEboth8

RP.PaintkrrstorBoMh (I) slightly more emdent (2) slightly more experuhrc

(2) far superior for certain applications (drm

W: DmrdDnU boo^ are a d a b l e in e k a d v Or water wash configuration. A downdraft booth is expensin, but is .Is0 the most emcien: booth smngement available.

5. SPECL4L. USE SPRAY BOOTHS Slimline 'WH" Booth (1) A spedslty booth for the furniture indwry.

d AndreaeNtn'Booth (1) lonee? lasting nltn

coueeting or PRED usage)

(2) Not technically a water wash booth u no m t l r cwtaln exiru. commpentty it is no(

intended to compete with water wash booths. A direct competitor l o the "Koch Sons" cavity-back booth.

B. Air Supply SyJtanr D M - b SysCmrr E"- a. Natural g s s - k a expenrive when aVjC

&le b. L P ~ ~ ~ ~ r p B e s Y N m L Stem-Noticeably more expensive than

d Elecuic-Prohibitively expensive llps

units operate with hea:ing element in thr air mam. Mow a minimum Of ( I ) week for securing mem or elcetric air supply prices.

c. Indirrcl-b system Energy Source

Oil-Unit is expensive. Oil requires a S U I I I N ~ ~ * and circulating syslem. Unity do not hyvi. modulnting control companble w ~ T I . ~ W units. Frequently have only "full-half-ofr modvlotion

Enerlor 8 W 8 S dmmnsmed 8re derign8led C l 8 u 1. Div 2 hlCIlOt 8W8S 8 I C deslgnaled C h S S 1, DlV 1. Exhaust F i n C ~ P ~ C I ~ Y IS determmed by multrplvmg all open Irea l b c c plus conveyor opentnqsl by me desired daciv 1:25 FPM lor open t8ce 000th. 1W FPM tor v8hicIe booth1

Ensf i f m a t dimensioned are designated Class 1, Div 2 Interior area$ are Class 1, Div. 1.

MI. OLOSSAFW OF TERMS USED WEN 0-N SPRAY Eoonis AIr Maks-Up Systsm-Thh b rqulred tu bring In &Mfllvrrd (llllmidined) airtorep~tht .pchrthc eJuuafanhsnmOved h d n a r Fibr-A 3re reurdu\c UIU C- d tm ahccts of perforated cormgated paper of un+ ILe which b attached at the C O M g U I O M . The dlta b mC Lpslble and folds up llke an .crordion When opened & pmvida a winding passage so that the conllrnLvted air rmhs the w.u1 of the dl tu fuuing the *tm stick or dmp out Of the air before bchg UhVlMd 'Ibis mer b rlso disposlbk. Baffle Booth--lhe simples form of .pny booth .SN& IKU mer to distribute the air wenlyulraugh the spny

8 .N

Bench Spny Booth-The work area has been ckvated rbove the floor to table height This type spray booth b vrcdtospnysnlaliitans. Booth Resistance-The rating b determined by the pressam differentid - the e l i " rccrionm$ir NLIuRd in inches Of antamhrmh 600th SCnw-A device rmde Of b r o w so It dl IwI( ueue a spark when ured in maping the huvybuUdup of dried paint off the wdb of the spny booth. Canopy Booth-Where a cover is placed over a spraying praacirrguiringthe m o d ofeontuntrvted air. C.ramic-lype Spray Booth-A specw type of rpny booth uaed whew cerunic type murri.L, mused mil which pennits the rechation of the ~vvrpny U 10 dairrd Compound-Additives added to the water which QILIRS the paint particks toeithallou on thesurhce or wdepnding on the typeboothbeing lned Reput.ble paint mylufDeomrs ue wulfy able topmvidethe pmp er compound for their'mteriah. When using a high re- si9&IIcebmthannpoundsshouldkieptto."ua tomid foaming. Heavy weight oii may u "rk used tommimize founmg. Conveyor Opening-An opening in a spray booth which permits work to k allid through Cnnr Ddt-Where the rir enters limn one aide of the booth and the uhuutcd rir ismmondfmmtheotha side. Dsclbsls IDBI-A unit of meuuring the m h bud. ne= of sound ordinarily detectable by the human UT. The measuring scale begins with number one for the faintest audible sound one can hur. Dispo-Spray Booth-A spray booth with a cloth uta which uaps overspray. DownlDratC Watsr Wash Spray Booth-??& spray

grating on the Ooor. This is the cleanest spray booth available for doing tlm Drafc Gauge-A device w d to m e " the prryurr d.i&mlIiai 94055 the BlterhnL and indicuawhenltis time (0 ch.nge the d l t e ~ . Eiimirator Section--lhe part of the booth where the -lid 7articles are mnond fmm the exhaused air.

boculmom the m n p n y Md paint lumattKougha

Exhaust Wmbor-A devlce tu wmut the end- at& = a tk+proof r" into s spny M Exhaurt Fan-The fan b wed to provlde suftlcient

m y booth ud nvinuin arilldent air nlocity. Explorion Proof Lights-Lighrs which are used in u e r r where dangerous vapon u e present which can QUY explosion or Ure. Explodon Pmof Motor-A qecidty built motor which can be operated in a locotion w h m solvent fumes are preacnL In some aptes this Gpc mom b rquired on .U V = Y boo& A l t n Door-A door fitted with fflten which yc ured to convea 8 mom or spray booth into a dun tree @ray p.int - Rttn 01 Ikv BDoth-A rpnybooth nith &proof di, pos@le paper fflten which trap ovenprayed panicles ber0m.the air b ahalmed to the ouoidc Flkntion Efficie~-Good 5laation b predicnlcd on the spraying ofone @Ion ofpa.int p a foot of booth thm feetfromtheeliminuorsectlonusingscpndudprrraves for one hour. The exhutsted air b sunpled Md not mom thvr flve rpplns of a p.niculu ryp putide ue to be prraenr In lo00 CFM. of &. High Tmpmtun Exhrult hnr-h aiuust h dc rigned with a rped.l shaft and beuingr to with~tpnd tsnpmtures from 4OTto (WT.

Low Rsrirt.no Waahsn-Opmte atth a e coC umn bd i f .c lonk lo r r. Most audud type tworhs ue brrrsiMnce beuuae-they ut gtnaaUy lowaincon udlomrh0penLingeosL~ ' Hioh Retirt.nu W.sh.n--Opcmte with a XUQ mi- umn indiution .bovc r. The higher the mistance the b e n c r t h e ~ o n ~ i ~ o f t h e b o o t h u d t h e h i g h . ertheopcntingcorr No-Pump Water Wash Spny ba th -A spny booth t h a t w s h & h a i r ~ c e t o ~ u i n a a n t a ~ vriar M.nhld-The pipe which dichibura the vpter to form the c u W n in the eliminuor sedlon of the spny booth. Paint Amstor Filter-A honey combed 5re retardant w ater which mps the paint wcrrpny, used on mter brp spny booths, this item b dwposable. %*TWO M o t a - O N E "E MOTUR WHERE its inner p.nJ are - to the ansidc umosphae. Plenum Chmbor--An u e a in which the pressure of the air endored rprce &-.than the wtside umw==. Somi-Dratt Spny hoth--whm the air enters from the top and is ~xhaused through one of the rides. The . p n y opentor should d e n t himelf so thu the mer- .pnyisnotFUwtowudhim SPW B0oth-h uu duigned IO -zany off aerspny and Yumu by of uhawtmg the rir fmm a spray

praam tu m(M the l-whd mount ofair through the

uu

152

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Statlc Prorrurr-The mount of resisunce which b

muc wi- aith the mount of air belngmovcd .nd Its dodty, length of suck, elbows. fflters, etc., nut wiU “ t i o n Totally Enclorod Motor-This motor is sealed In w that moisture ud paint pvdcles m o t reach the W e workings of the motor. Recommended to be used on . p n y booths where explosion-pmf moton are not re qulred to conform to (lkuxy Mutual) rqui”m Stripable Coating [Booth Coatlng)-A coating spayed on the WPlLs of the spray booth before It la uecd ’ h is coating vill simplify the r a n d of paint buUdup d h v w . Touch-Up Spray Booth-This la a very amdl type bench spray booth used to spray very snull ituns. Not Itcommcnded for poduetion. furntoblo-A rotating table to provide access to dl mder of ynu produn

pruent In my spny booth exh.ua rystrm. sutic P r e UpDntt-Where the lir enten h m the bot” of the booth ud u elhauslcd h m the top. Vapor l igh t Lights-One type of lights that are endosed w thot dangerow vapors are kept I” the wvrng of the hght dmue. Varsol-Typo Spray Booth-A specidly built spray booth for rohmt degreeumg ud c l e m g of pans m L booth. Solvents are rrelpuned ud recirculued.

water curtain whch cames the omspw purrcks into a coUechng pan. lhir spray booth removes a large qumuty 01 omsprtly perricles &om the w. It is also the d e s ( method I” to prrnnt fim. Weir Platr-A plate which holds the h d g e in front of the booth or m a holdmg areado LhU the overspny pant particles may be removed

Watar-Wa~h Spray Booth-A SpnY booth thu has 8

SELECTING A SPRAY BOOTH

IJ Which type of spray booth? WATER WASH-TYPE

,

Operator Techniques

GENERAL DESCRIPTION 11 is possible. unfortunately. when spny printing to do wml things mung m d stlli produet M IE d p u b l e flnlrh. One could then say “So why worry about technique?” The main reason is COST. Poor apnying techniques “It in the use of exetssive mounts of material m d perrcnri energy. ?his leads to hither rejection of the p m duct due to a poor final finish. me use of pmper technique is easy to develop. It is a matter of developing a good technique into a habit. Just as bad spnying techniques M leuntd, good techniques M be learned just .I easily. In the following outline. we will explain the basic principles of good techniques for spray painting with aides or conventional equipment. Note: The% are only starting points. There are excep tions to every rule and these exceptions will be determined by the individual job. BEFORE YOU START TO SPRAY The rpny run md 111 related equipment should bc dean and m proper working order. The spray p n should be checked to see that it produces a p m p r spray pattem. A proper spray pattern should be uniform in shape. panicle size. and panicle dismbution, with dearly defied boundries. There should be a minimum mount of partially atomized random pu- ticks outside the spray pattem boundry. Keeping pressures low will aid in the formation of a conen and uniform spray pattern with minimum off. spray and rebound.

TYPICAL 1 $:: SPRAY PATTERNS . . . ,. ::A(? i.2.;. @d ~ d

AIR AIRLESS

SPRAYING PRESIJRE A h o p Atomizing Pressure Is: 1. l b e minimum air pressure needed to atomize the fluid properly.* 2 An rir supply which will provide ruffic- ient volume (cfm) of rir to operate the nir nozzle efficiently.*

*For internal mix nozzles. atomizing pressure is in balance with the fluid pr tvum a i the spray gun.

8. Propsr Fluid Prmura Is:

I . The minimum fluid pressure needed to supply sufficient fluid to the spray gun to meet production requirements. 2’For intemal mix nozzles, fluid pressure is in balance with the atomizing air pressure at the rpny gun. 3. (With drlesr) the lowest possible fluid pressure which will 8tomize thr material PropcdY.

C. Rulc of the Thumb for Setting Plosurcs ’When the Spray Pattern is Right-The Pres- sures arc Right” (provided the lowest psst- ble pressures are used).

D. 0th Faetoo - The above rule will pen. erally get you started. but other factors that contribute to a final finish of high quality are: 1. The proper flowout of the fluid on the work. 2. The proper drying. curing. seninpup. or baking of the fiish. *Not required for airless %prawn$.

tV. SPRAYING TECHNIOUE A. G”l

1. Always have the spray gun in moilon be. fore triggering. 2. Keep the spray gun at the same distance from the work. 3. Move the spray pun aaoss the work at the same speed. 4. Always trigger the spray gun at the begin. ning and end of each stroke. 5 . Sun the first stroke at the same point on each similar object. 6. Put on a full wet mat whenever possible. I. Always overlap t h e previous stroke b! the same amount. 8. On similar pieces or work, always UY rhr m e number of nrokcr or pasrs. 9 . End the last stroke in the same piace on similar objects. B. Spray Gun Distmcl 1. Spray pn distance from the work should be approximately:

a. 6 to 8 inches. 01 the span ol your hand. for conwntional equivmcnt.

4. Avoid "heeling" or '%eing" the spray gun. Move your arm perpendicular to the work surface.

b. I ? 10 15 inches for airlesssDravinp. . . - C. IO lu I ? inches for electrostatic spraying.

2 Move the spray gun closer for a wet. dark. I i c i q . film build. 3 Miwe awa) from the wori. for a dry. I+?hl. film build o r for a mist or dust coat

C. Stroking I . Move the spray gun parallel to the work. 2. Keep the spray gun at 90'. oral right angles. to the work surface.

I ' / \Coatlngshould k d e n and m when spraying 6 to 8 inch-

I

' ' r Right - 3 Avoid "arcing" the spray gun. Move your arm and shoulder, not just your wrist

t dat ing Will be Carting wi l l be b v y I t this light at this point

,

Wrong

156

5 . Overhp a portion of the prewous stroke approximately:

a. 50% for conventional splsying. b. For airless spraying, overiap only that mount which is required to flll in and cover the prrvious stroke. or about 25%.

,-Aim fin1 stroke at pami edge

- . .-Stan stroke o"ersPrav without "banding"

6. Crosshatch overlap for a uniform coat when required. Use vertical strokes first. then horizonul strokes over the m e

7. 90U. gun travel gives a he3". wet. film build. 8. High pun travel gins a dr!, I lgh . fdm build.

1. Keep the nuid nozzle orifice and air. less tip dcm. Build.up of fluid on the flu. id nozzle orairlev tip may cause the spray gun lo deposit a heavy "blob" of paint on the work. 2. Reduce paint loss. 3. Prevent heavy build up of pain! on the corners and edges of the work 4. Prevent possible runs and up 31 tllc beginning and end of the stroke. 5 . Give the air.operatcd pump a chance to catch up in deliver! and mainiarn p r w sure.

m a .

D. 'Trimring" is Neded to:

.

1 E.T.chniqu- N d l d to Cow Trpiol M e a I . "Bud" the c d ~ e s of the product t i to include corners and pronounced con. IOUR.

a. Flat panels i. Spray bands at edges.

ii. Fin& panels with iioruontd strokes.

b. Table edges (ovenpny and rebound should fall toward unpainted surface),

E . Exterior comers (should be painted rust).

d. Interior corners i. Spray band 11 edpcr.

ii. Work out uf coriicrs. i1 i .h not spny directly into 1 comer.

Wrong

2. On long work, bmak the disrrncc down into 18 lo 36 inch strokes. Remcm. k r to trigger the rpny gun at the end or each.strokr and to feather the edge of pattern.

. . uncoated panion of parr being spravec

4. No1 dI sham a n be coated Ihc same Way. Each ObJea must be analyzed and the simplest. most drrcci. method should be used. Some typtal problem sham arc:

a. Open work -

b. Round

RIGHT,

lust three stroks to cove

C . Slcndcr

d. Special

Rotating work holder

5 . MOVEMENT of the spray gun over the product should be uniform.

V. CHECK LIST OF VARIABLES CONTROL. LING OUALITY IN SPRAY FINISHING

A. Atomization

I . nuld nrcoslty. 2. Air pressure. 3 . Fan pattern width. 4. Fluid vcloctty or fluid pressure. 5 . Fluid flou rate. 6. Distance or spray pun from work.

B. Evaporation Raw 1. Physical popenies of solvents (Le.. fast or slow evaporation. 2. Temperature

a. fluid b. Work c. Air

3. Exposed area of the surface sprayed. C. Evaporation B n w a n Spray Gun and

Sprayed Pan 1. Type or reducing went or solvent. 2. Atomization pressure. 3. Amount of reducing agent or solvent. 4. Temperature in rpny m a . 5. Degree of atomization.

A. ShopConditjoru . 1. Tempenrum 2 Humidity 3. Ventilation

E. Spray Equipmm and Adjustmono 1. Fluidnozzle 2 Air nozzle

4. Fan pattern width 5. Atomization prmure

3. Ruid now

C. Thinner 1. Type of thinnrr 2. Reduction ol color 3. Us+ of reruder

D. SPrayinp Tehniques 1. Gun distance

3. Flashtime 4. Mitnwt

2. Gunapeed

VI. VARIABLES AFFECTING COLOR IN METALLIC FINISHES

Increase knme Decrease lncreur

' Increase Decnnv

Smplln t r g r r More air w air 1 Increase Dwreasr increue Dcrrenv

DcefFue lnrnnw i

Faster Slower lncre'ase Decnw Do not use Add rrtardvr

Increme Wrew . Increase L k W W Increme knuw Will not Weltrr mirl ! lighten coat

I I

0. Evaporation from SpnW hrl I . Surface temperature. 2. Ambient air temperature. 3. Ambient air wiocity. 4. nash time between coats. 5 . flash time after find mats. 6. Physical properties of the solvents ( i t . . fast or slow evaporation).

E. Operator 1. Distanoc of spray gun from the work surface. 2. Stroking speed over the work surface. 3. Pattern overlap. 4. Spray gun attitude

a. Heeling b. Toeing c. Fanning

S. Triggering

I To Make Colon I

159

VII. 'COMM'DN TERMS USED IN CONNECT~ON WITH SPRAYING TECHNlaUES

Air Atomization - the p m s s by which jets Of air strike the fluid stream and break it up into finely upanted panicles M that the fluid can be distrib- uted evenly.

Air Rasure - the d e p of f o m or power at which the air is tnnsfered from the air compnssor to ppny gun and then to the spny nozzle. Pressure should be kept at a minimum yet high enough 10 give you the desired amount of atomization. rpny pattem, and finish that you require.

Fan Shape or Pmam - the resulting shape or design Y the atomized particles begin to build on the work surface. Using the fan control or side port control of a spray pun, a narrow fan may be p r o duced for edge.work and a wide fan for flat work. Remember. 8 narrow fan puts more paint in a small. e1 area. so you either have to work laster or cut back on the amount of fluid with the.sprry gun needle valve or by reducing fluid pressure.

Fluid Pressure - the d e p e of Iorce or power at which the fluid is delivered from the container to the fluid nozzle. Pressure should be kept at a mini. mum yet high enough to deliver the amount of materid which the opentor a n hmdle. High fluid prwure causes high fluid velocity which makes It more difficult to atomize the material. If loo high (maximum 18 psi at spray gun) fluid prmum is nerrrury b satisfy your fluid need% a I q r orifice nuid n o d e should be used in the spny wn.

T r i w i n g - the anion of turning the gun on and off. This should be done at the beginning and end' of each stroke.

Stroke - a sinerr movement of the spray gun across a spray area (normally not more than 36"). Similar to the stroke of a paint brush.

Ram - the number of repeat strokes which arc required to cover the object.

Gun S p e d - the sped at which the spray gun moves over the work surface.

Gun Dirunrz - the disiance the gun should be heid away from the work surface.

*ling and Taing - the tilting of the spray pun so the spray pattern IS no longer perpendicular to the work surface. This causes a heavier build-up of fluid at the bottom 01 top of your stroke.

Fanning or Arcing -waving of the spray gun back and fonh across the work in an arcing motior thus changing the distance of the spray gun IO thr work and causing uneven coaling and excessive 10s: of fluid due to over-spray.

C a t -the total amount of material applied prior to flashing off.

Tack Coat - I lirht coat of fluid put on the work 50 that later a heavier coat CUI be applied without the fluid sagging.

Mist C a t - I final c a t of appmximateiy 1W solid and 90% solvent used to "re-flow'' the prrvious colt.

Film Build - the thickness of the fluid which has been applied to the work. The toW amount or thickness of fluid adhering to the surface.

Full uwt - full-bodied wet coat requiring one or more p a s .

Flash Time -the Mnimum time it takes for the sol. wnt to leave the sprayed film before it is read) for recoating.

Om-bpping - the process of panidly covering the previous sprayed stroke. usudly given as a PI. enrage of new coverage (example - 505 lap. 25: lap. ere.).

Enpornion - the release of solvents from the fluid inlo the atmosphere.

Vaporintion - the process of turning liquid inin F.

CrwMching - the same as over4apping. except done in alternating venical and horizontal d i m . lions.

O m . S p a y - that fluid that is lost by missing t h e work.

Off-Smv - that fluid which is lost due to bounce. off or deflection.

. .

F

b W 8 . D * I . D W C V $

Reprinted by Binkt with permissm from Wood (L Wood ProductslNovember 1990.

HOW TO MAINTAIN A SPRAY GUN

A step-by-step guide for proper spray gun maintenance

BY J.W P. Hund BlnM yfg. co. A prowrfy mantamed spray should w o e N user wim years 01 Latslaclory s."e Fauny spray panem can be the resuii 01 an mproperly adlusted w poorly mainlam spray gun H 6 a precsion IWI and deserves tne same care and anention Pat any crabman gtves the look wth

Marrrtacluren 01 spray guns repon lhat m e often than not. mvestigalm of com plamn of dBlectwa spray guns usually reveal mprow care or abuse h adef fw a w a y gun to conuStently

poha PualQ rcwlcr. d W receive Im, typer of mantemme Fm. I( shordd receive a i l y rnamlenam wch as b@t hwatKn and dcanno scccrdly a corn *le omtaul6 meuary after a p l o d 01 maw s e w e Regardless 01 the spray gun tvpe (aa a u m . an asssled an&. nMP. ctcl cr manulacwn. all requnc proper mamlenarce

This a m k mll emDhasue the rum mendeo daily mintemme procedures of a sway cum Fvsi IC! s estabhsb haw rot to t e a l a w a y pvn Never totally submerge or soak a w a y pun ma conlalner 01 sct vent Dong so fills the gm s mtemal air and M passapways vim dKI contammaim bose Dam1 mnlcles resldue e t When the solvent 6 remved oflen much 01 the cmlamtm slays behlnd 10 Unmlely

l k w h Ihe air nome and enters the spray coaltnp causiw Mm delecls Soakmg a m y gun m solvent also removes all necessary kincabon of (he mecharml pans R M destroys pack@ &mer than a c[xIF W e soakng. umply rcmove noatcs and hps ard soak these pans separately tl w k n g 15 necessary lo remove meSe cwnpanenls. w h e r p e only me atlected areas k e e p g the way gun packin0 and gun rJeS out 01 me solvenl

&rand M m?zks.. tlnd neems. and aides t@s shadd receive vbnosl care when cleamg New use any!luq harder than tiass lo uaxlp clooped an mz!e pasrapeways u t&s Tunps(en cam aides and an asyned a u k s lm are very kmk and I& 10 beak easly A SMI bnr-

~ l c h he make ha livlnp

P l q Up the gun S OrifCB Of 15 &lodged

LUBRICATION POINTS OF A TYPICAL SPRAY GUN

are r e m e d . piow3 clbncatl~ 6 n

@aced on the needle valve where II enters the (kad packng p s t ahead 01 the bigw (Uluslratm item 2)

Tho nul. more CD"0nly relened to as the neede packbq gknd. sh43 never anow the pcktnp nude to cry out u do solve n ma OCM. IrrbnCale u replace

M d W . dOp Of llpmwelphl MI ShYJ!€I be

Controlling film thickness of coatings-on wood

320 480 640 800 ob0

$120 1280 1440 (boo 1760 19M 2080 2240 2400 2560 2720

ow important i s film thickness

performance properties of coatinp? hi051 suppliers of metal finishes

ind the manufacturers who use these. mducts have no problem answering ,his question.

The thin. dry film of paint (0.001 nch or M) which protects the metal ,an from w a r and corrosion also wovides the aesthetic properties of alor. texture and gloss to a myriad if metal i t e m from bottle caps to pact vehicles. The amount of paint ipplicd influences all of'thesc proper- ia.

Sophisticated application q u i p Rent is often used to transfer the tin- ih to the metal surface in a precise, conomic manner and the dry film hickness of the coating can be fairly. ccurately monitored by electronic or iagnctic instruments. In sharp contrast, the application

lethods used in most of today's wood irniture and cabinet manufacturing lanu. arc manual spray (either con- :ntional air or airless type). Wet or ry film thicknesses are seldom, if rer, measured.

I t appcars that the present mcth- is for applying coatings to noncon- ictive wood surfaces will not iangc dramatically in the immcdi- e future. Application equipment suppliers. iatings manufacturers and w d rniture and cabinet producers con- iue their cooperative efforts to im. 'ove the transfer efficiency of wood utings and these efforts hove met ith some success. In the meantime. however. steps

.n be taken to B P D I Y and measure.

H ' control to the application and

160 107 80 240 160 t 20 320 214 160 *oo 260 290 480 P O 240 560 370 280 640 425 320 720 480 360 800 S O 4 w 880 586 u o 960 640 480

1040 695 520 1120 748 560 lZ00 800 600 1280 854 640 1360 906 680 1UO %O 720

- *7 40.00 /

Wid. 10% 15% 20.*

- 25% 30.. 35.- 40.* 45% w. 55% 60% 65% 70% 75% 80.. 85% 00% 95%

100.-

2-1 '2 Mila 64 96

128 160 192 224 256 288 320 350 394 415 450 480 510 Y 5 575 608 640

fith some degree. of accuracy, the Im thickness of coatings on wood. nformation on some fairly inexpen- IVC. wet film gauges can be obtained

from your applications quipment or coatings supplier. Once a method for testing the film

thickness is established. follou a few

simple rules and you are on the n to reasonable control of your tini operation.

Don't try to monitor the thic

I

aeU Of WIor a u U such as low aolids ruins or tonm. 'rhw a x urunlly applied in very thin film and absorb quickly into the wood. Primers, basecoats or enamels should all be measured. Measure all clear films such as washcoau. sealers and topcoats and take the measurement in the spray booth, immediately after each coat is applied. Explain the purpose of your tests to the spray operator. Remem- ber. be or she has often ken spraying for a number of years, without guidance or controls. Your initial goal is to measure &e film. as it is presently a p plied, to determine whether or not it should be adjusted to pro. vide optimum propeniu to the finished pan.

9 Work with the sprayers to achieve consistency. The important thing is to apply the same film thickness. time after time.

It's surpr is ing how many sprayers M be trained to apply wet film. within i range of 0.001 inch. mnually. Once good spray techniques

' have teen developed, run some test picces to determine the right amount of mating for your product. Do not change the established spray techniques in order to achieve desired film thicknesses. Instead. anlit the services of your applications equipment supplier and matings manufacturer to optimize the fluid Row rates, tip sizes a d viscosities necessary to achieve desired film thickness in each spray operation.

Keep in mind the f a a that varia- tions in film thickness greatly inRu- cncc almost all of the appcarancc and functional propcnies of the wood finishes package, which protects and enhances the beauty of your pro-

dun . In iencnl. a total dry film of 2-3

mils of coating it sufficient to provide the daircd appcarancc and performance quilities IO properly prepared wood substrates.

Excessive film ~hicknesr. espccial- ly on horizontally sprayed surfaces, may well k the caux of such p rob lcms as blisters on open pored woods. lack of clarity after :he finish is rubbed and finish checking years after the produa is in the field.

In summary, stan controlling the size of that protective envelope which contributes 50 much to the saleability of your wood furniture. kitchen cabinet or T.V. console.

Oncc you establish the proper film build ncedcd to maintain the desired quality of your produa. keep it con- rirunr.

Finally, k sure you're not appl>- ing more material than needed to develop the finish propenics you want for your merchandise. 0

WET FILM THICKNESS GAGE

I = -0-

Acid catalyst iacquees- L q u c r rad ly d e of urea formaldehyde. melamine, and epoxy resins. set by poly- menntim. Alhd plnrticuen increase resistance to water and heat; Standard i s the two-component lacquer. made of lacquer resin and a separate acidic catalyst. which could consist of hvdrochloric acid. organic acid phosphate. mSA. etc. The pot lift ofthis mixturr is several h w n long.

Active solvent-A solvent capable of dissolving a resin by irxlf.

Additive-Any substance put into a coaring. usually in low concentrations. that helps cffccr the coating's physical characrerisrics. Among other things an addi. rive may be a colorant. an inhibitor. a pwrvative. or a stabilizer.

Adsorption technologv-

An - umml chat uses activated charcoal to WLorb VOG from the qmy booth exhaust. concentrate the solvents. and present them for either disposal or combuxm

A i r . d airless a"- tioa-A method of spray application that combines ainpny and airless tcchnolo- gla It d u e s the fluld pla- SUR common to airla, sw rems and uses a small amount of atomizing air to aid in atommnon

Airless atomization-A method of spray application that atornuts the finsh flud by pushing it thmugh a small onfice at high prruurc It ha transfer diciency dlpproxi- marely 50 percent: known for iu high rate of rped ycr mewhat coarse fin&

Airspray (see Compressed air otommtion)

Aromatic hydrocarbons- Powerful liquid solvent in

I*

vhich ring-hped molecules form the compound. wullly diuillcd from ccal ur. They ~ m t l y , u c wd but at rcl- ariwly Iw Iweb. Two common ammatic hydrocarbons compounds are toluene and - l e .

Bindcr--An ingrcdmr in a soin dut a l l w the pigment fo hold a sum in place when dzy. and gives the stain the right adhesiveness for a fin. ish. For example, a lacquer binder producer a stain that can k spongedncd quickly, while an oil or varnish binder n u k e a wiping stain chat u n k sprayed. dipped. or brushed on before being wiped OH

Bleached woods-Woods trcatcd to be light-colored. Most frequently used bleached woods include blonde mahogany and blonde walnut, which are poplar as cabinet wccds.

Bleaching-A process used to lighten wood when new

A

colon and shades are & i d .

BlinabDdectr in finlrhed

tions on the suriace. that lodr like skin bllrrm Usual- ly caused by the wood s u b king coated with something that doesn'r mix well with the chosen lacquer. also owed by mwd air. water. or ".

Blonde finishes-Darker w d char have k n arnfi- ciallv lightened Blonde shades include n.hite. eggshell, cream beige. and lqht bnnvn

Blonde treatment-A finishing technique that UKS a transparent rubbed finish to

nl p i n panm

Blush-Milky appearance in film c a d by the condew. tion of airborne moisturr in a film cooled by evaporating solvmu The cloudiness ma\

d produco, U5ualh eleva-

?CCCl!tUate the W d S N t U -

Finishing Terms

diuppev once the source of the moisture has been removed.

Bounce-back-The tenden. cy of a finishing material m lppy I O r e w or touncc off io intended nuface. The matcnnl. however. is uught in air M b u l a c c that c a w it not IO mch the surface. Usually a mult of high air prc+rurc in rurpnY.

Bridging-The ability of a coating to cover over an unfilled gap such as a cnck or comer.

Bubblcs-Air mpped in the wet film or the paint surface. Typically occurs when film IS excar1vely hlgh.

Build-The depth of a substrate given by i t s coating. Expressed in wedmils for wet lquid coatmgs or dty/miL for a cured coating.

Butyrate-A lacquer-like. UV-resistant resrn used in situations where good flow and light stabiliry are neces- yry qualities.

Catalyst-The reactive chemical that starts t he chemical bonding process when added 10 conversion coatings.

Catalytic incineracion- Type of incineration that utilizes a nonprccious meul catalyst to oxidize hydtour. bans at significantly lower tcmpranver to save operat- q c m .

Ceramic bed-A type of thenral oxidizer used to

bo0rheXh;lurr

Checking-Random cracks in hardened film caused by unFvm shnnking acmu the film’s surface. Temperature d u n g e r d i m p q e r d q m g between the film’s surface and h e thinner within the f lm can cause checking.

Cold check-Cndrr f m e d by the expansion and con- &on dlmng hot and cold cvda Combustion technology- hcinerator systems that combust. or thermally oxidize. VOCs in the spray bmcharhum.Thecnnba- rion .is accomplished using oneddvccryproflhnal ”: Mmu bed. p e l bai.ordirrnc”.

Compressed air acomiu- tion-A method of spray application that uses come p m K d air to beak up the catmg into mull panicla. E q u i p ” gcncnlly UVI m attached siphon cup or remote prrrwc cup. ranL. or pump for its fluid supp l~ . Transfer dhcimcv gmeralls is low due to h& amounts of air ~ u l c n c e .

Cndng-A defect in the film that m y a p p r as tiny cracks or wrinkles. I t is c a d by spraying herh lac. que1 on top of old fuwh.

canburt VOG in h e p a y

Cross-link-An atom or p u p joining adjacent molecules in a complex ImcNre making a chemical bond of p o l ~ e ~ . Cross-linking can occur with solvent elimination. heat, caulyrinp agenu. or high level of UV d a t i o n .

Cumin cmdng-Applying liquid fin. ish by psuing the flat subsmtc IO be finished under a thin film of liquid falling by pnnry or ptarmc.

Deep finishes-Finishes that darken wood and make substitutions of differ. cnt v c i c r had to detect. They appm d e in color due 10 hqh film build.

Dilumt-A marcrial chat cannor &IS- solve a =in by itxlf but merely diluta the resin material after it is dissolved inm m sctivc solvent.

Direct combustion-A type of thermal oxidizer used to combust VCGinthCm bmthcxhwx.

Elenrrnadc fin. uhing-A finishing process that e l e c d l y cturp.l ppintparridcr that when sprayed arc dnwn to the m d t d pam. The coaring ~ V C S a negative charge and the r~b5uue “I have a positive charge rbr atmaion m take p k .

Emulsion cmfing-A waterbased coar- mg, a latex. in which min panicles m held drspncd duwghout the warer by means of an emulimg agent.

Engineering contmGThe name p e n to methods char reduce V K emission h e r the finuhing pma.

Et-An organic compound or number of campoundr made b the reaction of an alcohol with an organic acid or dvd t idc . has m uud in ninoccllu- low lacquer.

Fder-Any arbrtace & m fill hola and inegulantia in planed or sanded S U ~ C K More the application of a coar- mg.

Finishing Terms

RJrPSrmllUKhh.". k cud bv Jw dirn dd p. uli. -0ndUl .n ip .

Rub piol-l"mn m rhvh, ~ h D r d v r k D u r n v f ~ s O m . hmllrnsrvlhlnnd

daldnhpmndauoa.im nTWUk-%dI. NndOn Specks d

rmhmdiea

of hnuh and h a i c d SUR=*. the rtlvlr d h rmpd bubbh w" drhMh

- % - - a h

G&nrdepee W r h r h .aOmq * d l r W & " n .

Glycol ethcrr-A type of oxygenated organic compound used in wivenu. most commonly in slow-drying lacqua.

Gnin nirinpThe sulelhg of wood fibers caused by moisture. Not reversible OIlCeUlOlmncisgCS%C

Gnwl bed-A ryp dthP. mJ oxidira wed tocombun VOCs in the spray booth exh;lun

Halogenated hydrocar. bons-A group of com. pounds d u t generally form weak solvents. They are found most often in degteascrs and arc most effective in removing wax. grease. and oil. May cause fue or explosion if m conmct wich aluminum.

High.volumc, low-pressure atomization-A finishing mthcd chat UVI a high volume of air at low p u r e for atomization. This decreases the fluid's forward vclocicy and increases mnsier efficiency. Also known as HVLP. Typically defined a5 atomization at less than 10 pi.

Intercom adhesion-The

a n t d DdhaM of all can m d nher wchm a multi- cat firurh.

JapnninpThe substicution dpnt for layers of wnrch This technique i s used in Europe and Amenu to CR- netheeffectofonadlac- -. Kctones-Any of a c l w of organic compounds chat ye

charactenred by a carbonyl grcuparpchedtorarocarbm atoms. For example. methyl ethyl ketone i s a common

ustor oil or glycerine p h i . cizers. dissolved in various aromatic hydrocarbon solvents, wd to achieve gccd heat-, water- and spirit-dco- hol-rPL(tMt properties.

Oil finish-A 50/50 mixture of raw linseed oil and 'boiled" linseed oil used to create a finish that will enhance rhe M& color of Woodrarch Y mahogany and walnut; a close.to.the.wd . finirh.

Oil paint-A resin based solvent urcd wlrh many finuhing materials. It i s verg volaole d a smng lolvau.

laquer-Coatmg mtenal that i s based on synthetic thennoplastic film fonnmg mataml dlwlved In l o l ~ h g LI p n m h h0Ud-l dnnt MpDernoh

Lacquer thinner-Sub- uarm rhpruMUyccannrs d shout 30 percent cnm and ~ O d y s s p V C S J l v Q I L diluted with aromatic and aliphatic hydrocarbons. These rolvents are very voliflle and should be wd only when d m d not as a rubmcun ckaung solvent

Lifting-A topcoat pullang away froln a tPceccnt due to mcompatibilicy, poor adhesion. or both. Often this d e m a wnnklal Id on the *. M " - A sunple molcc- uLr compound rhat chemically b o d with another to form a polymer.

Niaoccllul-A group of resins used in lacquers for clmty. q u i c h ~ of drvlng, and rrpayabihry.

Nitrocellulore lacquers- Cocrtrng composed of niuo- cellulose. alkyd resin. and

catlng coneinlng a surpn. sion of p i p e n s that form an opaque film through a combination ofsolwnr evap orstion and the curing oiL (x

poly".

Orange peel-condition CIUyd by paor atomization, improper breakup. or the implopr Mponlion of sol- M 1 D ~ f l o v a n o f rhe d m the b- ing cgclc. The descriptive term used to describe the bumpy texture common to thir problem.

Overspray-Any spray. applied f& not amcred morrnwdbyrhepmduct rurface; it is caused by i"per I p n Y tcduusue excessive air or hydraulic pressure. This misdirected f i n d can dcy in flight and caw &ear if it lands on a M&.

Pa in t -hy pigmented mm liquad designed for appliu- tion to a subsmte in a thin layer that converts to an -ut solid film a k a application and culmg.

Patina-A surface texture produced by age. wear, or rubbmg.

Photoinitiator-A material h t h r b s impingw lighr

and induces polynterication. This material commonly is wed in W-cmble f m i e r .

Photosensitizer-A substance upable of sensitizing anothcr substance to lays to which it would oot normally ma.

%mcnt load-The amount of dry pigment in a coati%. I& called Solids content.

polvmrr-A large molecule chemically formed by bond. ing monomers. Many times they can bc hnhn reacted to form luen polymm.

Polyurethane lacquer- Gating good for adhesion, flexibility. gloss, and water uul chtmical mistance.

Pot life-Lsngd~ of time in which a plural component material is nil1 usable h e r Cdysis.

Print mLtanc+-The abili- ry d a copring to mdt raklng on the imprint of another anhct placed aglmc It.

Radiation curing-The use of enqy uavelurg u o i a v e motion for hardening a flnuh.

Reactive f h h e d o a t i n g that hardens by meam of a complex chemical reaction to form a polymer. During the curing process the wet film atsarbs oxygen iron the air. then starts a reaction that proceeds through the film. c h a n p g ir f" liquid to wlid.

Rubbed finish-Finuh thar results from posr.finishing cpentions rtut mechaniullv mwrh. flatten. and p o l i a flat surface. rypicallt. table- topr or other hon-onol surfaces. The process i s wed to

166

Finishing Toms

obmm ~ r r l high gloar IcveL.

Sandabiliry-The ease with which a c a t i g can be d e d without dragging or gumming the sanding medium.

Sanding rulers-Fastedrying solvent. relclu mtcruL wd on bare wood to fd h e porrr and level the anhce More applying any &I fiiuh

Sealer-A coating that can slightly raue the woodgrain fiber and seal the rvmd Upon sanding it leaves a smoorh surface and provides a nonabsorptive surface to apply rhc next hturh coatmg.

Shrinkage-Usually assocnted with exrnuivelg uau-linked films, vuiblc rhc amount of curling induced on the subsnare

Solid color s-aque stam that arc a surpnslon of pigmenu m nthn a dving oiUorganic solvent muwe OI a water/polymer emulsion designed to

coior and protect a wood surface by formmg a film.

Solvent-release finirhes-Coatinp (such P( shellac or laqun) chat f o m a miid film upon evapontion of the 101. vent ot thinner. Typically called "air dry" matenalr.

Stains-A material that can cause wmd to color ro &ram effccu of color and gram ddmition.

Strippingdcmoving the old finish h a s u r f a c e .

Synthetic Iacqucrs-Coatings that greatly increase heat. water, and spinr resistance and have tough films and w gl=

Telcgnphing/ghosring-The rransmit- hng of surface mcgulanner in a b0~0m- a t through to a twoat.

Tbixottophy-A characteristic that describes a fluid's behavior. A thuonuph~c flud typially u vny thick a heavy &n xren tix when pumped

or aglcared kma tncmsmgly chin

Toner-A low- solids. lightly pip. mcnted stain - usually contains bmder.

Tnnrfcr efficiency-The total mount ofhuhlng mtmal that lcava the finish application apparatus compared to the amount of fmuh chat acm- ally rndr up on the pur. The value IS

exprerred as a percentage. The higher the transfer efficiency. the less costly the huhmg wrem d b e ro operate

Ultnviolct-Radiant energy beyond the visible r p c r " at the violet end; =vel+ h shorter than visible light d l O n e e r h X r a y *

UV -The rrcarliing of a mace- rial upon iB urpoarre to uimviolet ndi- aum

W -The resisrance a c u d f t l m h p ) I D y c ~ or challung whm aeparad to ulmvioln dium.

V i T h e degree to which a coat. ing mire flow OI movemr.

VOC-The weight and/or content of volatile organic Mnpound (solvent) in agallcnofccating.

Vduilc--Anv material rhat can evapo- m e undu nomvrl condiuonr.

Washcoat-A lowv-solids coating applied under a scam to limir p c m . ucn of rhe pigmenrs mto rhe w d .

Wbirkering-A process rhat helps elimuute gram rauing. F m the surface d the wood u wt. then flamedned to d e the fibnus mdr c a y to remove.

Wnparound-In clectrosraric finishing. finish pamcles are drawn to the mvme 01 bck side of the subsware due to clecnomatic amacuon.

bnu nu" for h~ mnck UII~ cmmbturd h: 1- Hund. B& Mrmvinrcmg Co.: Thomas Ellis. Chrru S?sccmi Inc.. John T d . DcVilku Fk"g I&md C w - w w: M b M ~ . Grnro. I=.: " d h W m . iJ&IndUnnu. Ix

8lW2. DI1u COmmun~tm. 1%.

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