Vacuum Systems for Extruder Applications

Vacuum Systems

for Extruder

Applications

Tony Solazzo, M.S.Ch.E.

Director of Sales & Marketing

Wintek Corporation

230 US Hwy 206, STE 401, Flanders, NJ 07836

973-252-8200 email: [email protected]

Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Who is Wintek?

Design & Supply Vacuum and Solvent Recovery Vacuum Systems

Liquid Ring

Steam Jet/Liquid Ring

Boosted Liquid Ring

Rotary Vane / Rotary Piston

OTO Rotary Vane

Dry

Design, Engineering, Fabrication and Ongoing Parts and technical support services, since 1986

Designed and fabricated >275 vacuum systems for extruder manufacturers and operating plants.



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Agenda

Basics: Vacuum Technology 101

Rotary Vane & Piston Pump - Basics

Dry Pumps – Basics

Liquid Ring Vacuum Pump - Basics

Add’l Considerations for Extruder Applications



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Introduction to Vacuum Units

The term “vacuum” is used to describe the zone of pressure below

atmospheric pressure.

Units of measure:

Torr, mbar, “HgV, “HgA, psia.

Common Standards

“HgV, - inches of mercury vacuum

Gauge Vacuum

0” HgV (atmospheric pressure) to 29.92” HgV (perfect vacuum).

“HgA – inches of mercury absolute

Absolute zero reference

29.92” HgA (atmospheric pressure) to 0” HgA (perfect vacuum).



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Introduction to Vacuum Units Other absolute units of measure:

1 atmosphere = 760Torr = 760 mmHg = 1013 mbar = 14.7 psia

= 101.3 kPa = 406.8 “H2O A = 1.03 kg/sq.cm



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Converting a “gauge” reading to absolute

Use barometric pressure instead of 29.92”Hg.

Example:

Barometer today is 30.3”Hg

Vacuum gauge reads 29”HgV

Absolute reading 30.3”- 29”= 1.3”HgA

Higher vacuum ranges (low absolute pressures)

Torr

1 Torr = 1mm Hg … absolute pressure.

1” = 25.4 mm = 25.4 Torr,

barometric pressure = 30.3”HgA x 25.4 = 769.2 Torr.

Converting Absolute vs Gauge



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SCFM vs ACFM SCFM is measured at standard conditions

68ºF, 29.92”HgA or 14.7 psia.

ACFM is measured at actual inlet conditions.

pump curves are in ACFM

Conversion from SCFM to ACFM - from the ideal gas laws

specifically Boyle’s Law

P1 V1 = P2 V2

***all numbers need to be in absolute units



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Example: SCFM ACFM Convert 20 SCFM of air to ACFM

• at a vacuum level of 25”HgV

• at sea level with a Barometer of 29.52”HgA.

1) First convert 25”Hg gauge to “Hg absolute

P2 = 29.52 - 25 = 4.52”HgA.

2) Apply the formula P1 V1 = P2 V2

29.92 x 20 SCFM = 4.52 x V2 ACFM

=> V2 = 133 ACFM.

•Conversion applies when the temperature is 68ºF.

•At varied temperatures the formula will be

P1 V1 / T1 = P2 V2 / T2

•At 240 deg. F, => V2 = 176 ACFM Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Vapor Pressure / Boiling Point

Dalton’s law of partial pressures:

P (total) = P(a) + P(b) + P (c) + …

Y(a) = P(a) / P(total)

A liquid will boil when the total pressure in the system is reduced

•BP Water = 212oF , pressure = 760 Torr (29.92”HgA, or 0”HgV).

•BP Water = 77oF , pressure = 23 Torr ( 0.92”HgA or 29”HgV)

If a vessel has liquid in it, you can only pull a vacuum to the vapor pressure

of that liquid (ie: it boils).

Can only reduce the pressure further (deeper vacuum)

if the liquid is removed, or the temperature is reduced. Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Solids Carryover

Liquid Carryover

Vapors that condense and solidify



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Rotary Vane Vacuum Pumps



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Rotary Vane Vacuum Pump



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Rotary Vane Operation



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OTO Vane Pump Systems

15 HP OTO Vane Vacuum Pump

Extended Fresh Oil Tank

Air Cooler

Waste Tank



Oil Rotary Vane Vacuum

Pumps

High Vacuum to 0.4 Torr

Composite long life vanes

Compact

Direct Drive TEFC motors

99.9% Oil-free exhaust

Air-cooled

Relatively Low noise level (79-81dBA)



Limitations of

Oil Lubricated Rotary Vane

Can NOT tolerate any liquid or solid carry-over

vane breakage, bearing problems

Oil breakdown affects lubrication

sticky vanes/wash boarding

Higher Maintenance Costs:

Clean service oil changes: 500 hrs

Waste generation from frequent oil changes

Not a good choice for solvent applications



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Rotary Piston Vacuum Pump

Shaft

Tri-piston Arrangement

Cam

Piston

Slide

Pin



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Rotary Piston

Discharge

Valve

Slide

Pin

Oil seal

Intake

Valve

Piston

Cam

Suction

Compression Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Rotary Piston Vacuum Pump



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Dry Vacuum Pumps



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Dry Screw Vacuum Pumps

•Simple flow path, similar to extruder…pressure control through

speed control

•No Water, No Oil in contact with process vapors – no contamination

•Can operate at high and low pressures ( < 1 mBar).

•Vapors have no effect on vacuum level. Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Dry Screw Vacuum Pump Limitations

•Only cooled outside casing, so that hotspots could develop

and gases could reach over 500oF.

•Continuous air purge required to cool the screws. Some

stepped screws do not require air-cooling

•Screws and shaft also get hot, affecting the mechanical seals

and bearings.

•Carry-over of process can stick to screws and seals.



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Dry Claw



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Dry Considerations

Operate Hot (some to 500oF)

Polymerization can be a problem

Accumulate buildup (not self flushing)

Bare iron – unprotected

Use of PFA (teflon) Coating

Not typically for corrosion protection



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Liquid Ring Vacuum Pumps



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Liquid Ring Basics

Distance from

Impeller to Housing

Large Open Area Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Liquid Ring Basics

Sealant liquid

is a little below

shaft center

line.



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Liquid-ring

formed Contraction

Expansion

How Liquid-Ring Vacuum Pumps Work:



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Suction created

in the expanding

volume




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Expelled thru

discharge

Compressed




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Two-Stage LRVPs



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Once through Water (Sealant)

Sealant In Sealant Out



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Full Recovery (Closed Loop)



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Motor Separator

Tank

Sealant heat exchanger

LRVP



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Recirculating Sealant liquid

No Waste Generation

Condense in Pump

Ingest Liquid

Excellent Scrubber

Cool through heat exchanger



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Water Temperature



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Water or Solvent Sealed

Vapor Press Dependent

Solvents

Temperature

Temperature Rise

1-stage

2-stage

Alcohols including:

Methanol, Ethanol, Butanol, IPA, etc. ..

Other solvents including:

MEK, Toluene, Hexane, Heptane,

Decane, THF, DMF,

Di-Octyl-Phthalate, Acetonitrile… etc.

DT = dT1 + dT2



WINTEK Corporation 2-Stage, 10 °F approach

End Pressure vs CW Temp End Press 10

oF 35

oF 50

oF 85

oF Typ.

Temp.rise Water <FP 20 torr 30 torr 55 torr 8

oF

Acetone

77 140 195 460 23

oF

MeOH 40 74 105 273 20oF

Limonene ~15 15 20 25 25oF



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2-stage, 10 HP Dry Air

Performance (35oF CW)

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0

In le t P r e s s u r e (to r r )

AC

FM

L im o n e ne W a te r M e th a n o l A c e to n e



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120oF Vapor, 45oF Sealwater

Liquid Ring Performance

Dry Air Vs Saturated

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0

In le t P r e s s u r e (to r r )

AC

FM

5 0 % W ate r - 5 0 % A ir (w t.) D ry A ir C a p a c ity



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Advantages of

Liquid Ring Pumps Rugged Design - High Reliability

Can ingest gallons of liquid

Can ingest powders and soft solids

Can operate with backpressure to 10 psig

Condense within Pump

Solvent Recovery

Simple Pump Design

Materials: CI, 316SS, Hastelloy Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Limitations of

Liquid Ring Pumps

o Vapor Pressure Limited

o End Pressure Limited ~25 Torr

o Sealant Contamination affects Performance

o Requires Cooling Water or possibly Chilled

Water



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VmaxTM Oil-sealed Liquid Ring High Reliability

Deeper End Vacuum

Oil used for Sealant (in lieu of water), NOT lubrication

No rusting

No hard water deposits

Air-cooled or water cooled

Carryover can plug auxiliary equipment.



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Achieving Lower Operating Pressures

with Liquid Ring Pumps

Addition of Air Jet

Extends range to 10-20 Torr

No environmental impact

No additional moving parts

Sacrifice of Efficiency Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Air Jets for Lower Operating Pressures



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High Vacuum (Boosted)

Liquid Ring Vacuum System

Can Extend Operating Pressure to .05 Torr

Increase Capacity at High Vacuum

Overcomes Vapor Pressure Limitations

Cost Effective

Potential for plugging



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High Vacuum (Boosted)

Liquid Ring Vacuum System



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Booster/Air Jet/Liquid Ring

Vacuum System

0

100

200

300

400

500

0.1 1 10 100 1000

Inlet Pressure (torr)

AC

FM

0

50

100

150

200

250

300

350

Te

mp

era

ture

(o

F)

Booster ACFM LR Pump ACFM

Booster Temperature Temperature Limit

Specify the Required Operating Range of Booster

Require estimated Performance and Temperature Curves



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High Vacuum (Boosted) Liquid Ring

Vacuum System

Booster

Booster

Intercooler

2-stage LRVP



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Liquid Ring Oil Piston/Vane Dry

Yes Able to ingest liquids NO NO

Yes Able to ingest soft solids NO NO

Yes Able to handle high condensable loads NO, need to

prevent

condensation

NO

18”to 29”HGV Operating Range 24”HGV to ~.5

Torr

18”HGV- ~0.5

Torr

No Able to handle acids No No

Yes Affected by Solvent Contamination Yes No

Lower Maintenance Level Higher High

Dry Oil Vane Liquid

Ring

Comparison



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Extruder Applications:

Additional Considerations

Solvents/Volatile Organics

Monomer/Solids Carryover



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Additional Considerations


Addition

of

Condenser

and

Receiver



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Condenser/Receiver/Vacuum System


Addition

of

Condenser

and

Receiver



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Condensing into LRVP




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Inlet Knockout Pot

Prevents liquid and solid

carryover

Protection by

– velocity changes

– directional changes

– several levels of

impingement



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Inlet Knockout Pot

1. Inlet impingement

2. Course demister

3. Fine filter



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Inlet Knockout Pot



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Inlet Knockout Pot



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Conclusions

Several vacuum technologies with different design

variations

Good understanding of the process characteristics

is essential.

Evaluate each technology’s ability to handle your

unique process

Include design enhancements for liquid/solvent

recovery and process carryover



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Thank you!!

Contact Information

Tony Solazzo

Director of Sales & Marketing

Wintek Corporation

Flanders, NJ

Phone: 973.252.8200 x13

Email: [email protected]



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Upcoming Webinar Schedule

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Presented by Mark Tate, Gala Industries

November 12, 2014

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Presented by Adam Dreiblatt, Century Extrusion

December 11, 2014

Visit our website to register for free webinars

www.centuryextrusion.com



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consent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Questions?

Thank You For

Participating!

Please send us your vacuum questions,

suggestions for future Webinar topics, etc…



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Contact Us

Tom Urban [email protected]

Letha Polk [email protected]

James Drummond [email protected]

Michelle Zhang [email protected]

Bill Goehman [email protected]

Bart Hautala [email protected]

Steve Misiak [email protected]

For general inquiries [email protected]

(231) 947-6400

Website www.centuryextrusion.com Licensed for the exclusive use of the registered user as downloaded. Must not be disseminated, reproduced, or presented without theconsent of Century Extrusion ("CX"). This document is digitally watermarked. The information herein is provided as-is and all rightsassociated therewith remain the property of CX.


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Vacuum Systems for Extruder Applications