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GESTRA Non-Return (Check) Valves
GESTRA GmbHMünchener Straße 77, D-28215 Bremen
P.O. Box 105460, D-28054 Bremen
Telephone +49 (0)421-3503-0
Telefax +49 (0)421-3503-393
E-mail [email protected]
Internet www.gestra.de
A Unit of Flowserve Corporation
810107-03/1002 W · © 2002 · GESTRA GmbH · Bremen · Printed in Germany
With Energy into the Future
Contents
Non-Return (Check) Valves in a Steam and Condensate System 2
Non-Return (Check) Valves in HVAC Technology 3
GESTRA DISCO® Non-Return Valves 4–7
GESTRA DISCO® Non-Return Valves RK 8–9
GESTRA DISCO® Non-Return Valves RK 86 and 86A 10–11
GESTRA DISCO® Non-Return Valves RK (HVAC) 12–13
GESTRA Gravity Circulation Checks SBO 14–15
GESTRA DISCOCHECK® Dual-Plate Check Valves BB 16–21
GESTRA NAF Check Valves 22–23
GESTRA DISCOCHECK® Swing Check Valves CB and WB 24–25
Selection and Sizing of Check Valves 26
Application Examples 27
Process steam
Flash steam/gas
Fuel
Intermittentboiler blowdown
Blowdownreceiver
Cooling water
Electrical pressure control
Cooling water
Blowdown
Deaeratingunit
Heat exchanger
Fresh/softwater
Monitoring ofconductivity
Heatexchanger
Controlled fromthe condensate side
Mechanicaltemperaturecontrol
Electricaltemperaturecontrol
Monitoring ofturbidity
Condensatetank
Steam dryer/purifier
Boilerautomationas per TRD 604
Economizer
Flashvessel
Flash vessel
Measure-ment datafrom boilerhouse
Production measure-ment data
Sight glass
Steam trap
Non-return valve
Steam flow measurement
Steam flowmeasurement
SPECTOR control
Stack
Boiler
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Non-Return (Check) Valves in a Steam and Condensate System
Applications
Vacuum breakerPrevents vacuum formation and damage to the vessel
Foot valve Stops the suction line from running dry when the fuel pump is switched off
Preventing backflowProtects the plant against back-flow in the event of malfunction/ failure of components
Ensuring unidirectional flowPrevents reverse running when pumps arranged in parallel are switched over
Non-return valve action for condensate line Prevents banking-up of conden-sate when the heat exchanger is off, and water hammer within the heating surfaces when the plant is started up again
Non-return valveTo ensure forced flow
Other applications not shown inthe schematic:
◗ Vent valve, relief valve◗ Overflow valve
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A few application examples
Here are a few examples forapplication using the non-returnvalves from our product range. If you need further support foryour particular requirements, wewill be happy to assist.
RK 86 (up to DN 100): solvents;coolants, cooling water; steam con-densates; neutral, alkaline andweak-acid saline solutions; ammoniaand ammonium hydroxide; causticsoda up to 20%; boric acid, fattyacids, diesel oil, heating oils
RK 86A: Pure steam* (for SIP appli-cations); drinking water; swimming-pool water; media of the foodstuffindustry* (e.g. dairies); mineral oilindustry; aggressive media such asformic acid (up to 50%), acetic acid,caustic soda (up to 50% and 50°C),phosphoric acid, nitric acid (up to50%), sulphuric acid (> 95%)
RK 16A: as for RK 86A
RK 16C: Highly aggressive mediasuch as hydrochloric acid up to10% at room temperature, sul-phuric acid in all concentrations upto 50°C, formic acid and nitric acidin all concentrations, bleaching lye,chloroacetic acid, chlorosulphonicacid, chlorine
RK 49: Applications at high pressures:steam, condensate, hydraulic oil
RK 70: Heating systems, air handling
RK 41 (up to DN 100): Heating in-stallations and district heating plants,cooling water, mineral oils, gases
MB 14: Heating plants, drinkingwater, cooling water
* For these applications, pleaseorder as pickled version
GESTRA non-return valves RK downstream of cooling water pumps GESTRA dual-plate check valves BBdownstream of bilge pumps
Your partner for theoptimum valve design of your installation
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Non-Return (Check) Valves in HVAC Technology
Ensuring unidirectional flow
Prevents reverse running whenpumps arranged in parallel areswitched over
Gravity circulation check
Prevents circulation caused by gravity
Foot valve
Stops the suction line fromrunning dry when the pump isswitched off
Return line
Burner with pump
Preventing backflow
Protects the pump againstbackflow after it is switched off
Boiler
Feed flow
Return flow
RK
Boiler
Safety return flowSafety feed flow
Feed flow Return flow
Mixer
RK
Standbytank
Solarcollector
Boiler
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GESTRA DISCO® Non-Return Valves
Today GESTRA can look backwith pride on one hundred yearsof experience in valve manufac-ture. The company offers a broadrange of DISCO® non-returnvalves tailored to fulfil the mostdiverse of applications andcustomer requirements.
All valves are made of diverse ma-terials to meet particular demands,and the individual valve compon-ents are optimally coordinated witheach other.
Through this ideal mixture ofdifferent components in the rangeof standard valves, the best valvecan be delivered for almost everyapplication. Here it does not matterwhether a thermally critical appli-cation must be safeguarded, orwhether a non-return valve must bedesigned for operation in oxygen,for example. It is even possible tomanufacture the DISCO® valve,which has proven its worth a milliontimes over, in a special material toanswer specific needs. All GESTRAnon-return valves are of the wafertype and have extremely shortoverall lengths. Thanks to theirexcellent design and hydrodynamic
features, these valves offer clear ad-vantages over conventional types:
◗ Compact design◗ Low weight◗ Mounting in any position◗ Low installation costs◗ Wide choice of materials◗ Space-saving stockkeeping◗ Safe operation of industrial plants◗ Low pressure drop
The name GESTRA is a guaranteeof high manufacturing quality for theGESTRA DISCO® non-return valves.
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Functional principle
The spring-assisted DISCO® non-return valve opens when theopening force exceeds the closingforce. The opening force dependson the pressure or the volume
flow, and the closing force on thetension of the closing spring, on theclosing weight, on the installationposition and the size of the non-return valve.
Installation
GESTRA DISCO® non-return valvescan be installed in any position, withthe sole exception of the valvessupplied without a spring. Thesevalves can only be installed in verticallines with upward flow.
GESTRA DISCO® non-return valve withspiral centering, DN 15–100 ( 1/2–4")
GESTRA DISCO® non-return valve withself-centering body, DN 15–100 ( 1/2–4")
GESTRA DISCO® non-return valve in thefully open state
GESTRA DISCO® non-return valve in theclosed state
GESTRA offers valves of high manufacturingquality for safe plantoperation
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GESTRA DISCO® Non-Return Valves
Short overall length, lowweight
Valves with short face-to-facedimensions reduce the weight andsize of a plant. As the figure belowdemonstrates, the overall length of a GESTRA non-return valve is only1/8 that of a conventional non-returnvalve. The overall lengths complywith DIN EN 558-1 and 558-2, series49 and 52 (K4/K5).
The wafer design drastically re-duces the weight in comparison withconventional valves. A GESTRA non-return valve of stainless steel in DN 200 weighs 23 kg, whilst theweight of the corresponding con-ventional type is 120kg!
Connections of your choice
For flanges to ASME RF/RJ, DIN2512, DIN 2513 or to worksstandards.
Materials
◗ Hot-pressed brass◗ Special brass◗ Cast bronze◗ Grey cast iron◗ High-temperature ferritic cast steel◗ Stainless steel / cast steel◗ Austenitic steel / cast steel◗ High-temperature austenitic
cast steel◗ Hastelloy C
Special materials available onrequest.
Tight shut-off
GESTRA non-return valves aretested in accordance with the testspecifications laid down in DIN3230, part 3, “BN” (tightness testwith water) and “BO” (tightness testwith air).
Valves with a metal-to-metal seatattain values complying with BN2/BO3. For units with a soft seat, therequirements of BN1/BO1 are met.
Nominal Overall length L in mmwidth DN Seriesmm in 49 5215 1/2 16 2520 3/4 19 31.525 1 22 35.532 11/4 28 4040 11/2 31.5 4550 2 40 5665 21/2 46 6380 3 50 71
100 4 60 80125 5 90 110150 6 106 125200 8 140 160
RK 70Hot-pressed brass / valve disc of plasticFor flanges PN 6 / 10 / 16Heating installations up to 100°C, compressed-air systems
RK 71Hot-pressed brass / valve disc of austenitic steelFor flanges PN 6 / 10 / 16Heating installations, higher temperatures
RK 41Special brass / valve disc of austenitic steelPN 6 / 10 / 16Liquids, gases, vapours / for industrial and heating plants
RK 44Cast brass / valve disc of austenitic steelPN 6 / 10 / 16Liquids, gases, vapours
RK 76Chromium steel / valve disc of austenitic steelPN 6 / 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFLiquids, gases, vapours / for industrial and heating plants
RK 86Stainless steel / valve disc of austenitic steelPN 6 / 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFLiquids, gases, vapours / high corrosion resistance
RK 86AAustenitic steelPN 6 / 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFCorrosive liquids, gases, vapours, acids, alkalis
RK 16AAustenitic steelPN 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFCorrosive liquids, gases, vapours, acids, alkalis
RK 49High-temperature austenitic cast steelPN 63 / 100 / 160Liquids, gases, vapours at high temperatures (up to 450°C)
RK 16CHastelloy C or equivalent nickel alloysPN 10 / 16 / 25 / 40Particularly corrosive media
Diese Nennweitenbitte als RK 86Abestellen
Steel / cast steelPN 10 / 16 / 25 / 40
Austenitic steel /aust. cast steelPN 10 / 16 / 25 / 40
Please order these sizes as RK 86A
High-temperatureferritic cast steelPN 63 / 100 / 160
On request
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Valves with soft seat
Non-return valves provided with ametallic disc are also available onrequest with a soft seat made of:◗ EPDM (ethylene-propylene
rubber) suitable for water and steam, max. temperature 150°C.
◗ FPM (fluoro-rubber) for mineral oil and gases, max. temperature 200°C.
◗ PTFE (Teflon) for corrosive media,max. temperature 200°C.
Non-return valves for boilerfeedwater lines
The non-return valves listed oppositemeet the stipulations of TRD 110and the VdTÜV bulletin 451-72/3(German regulations on steamboilers).
Valve type
1" 2" 3" 4" 5" 6" 8"15mm 20mm 25mm 32mm 40mm 50mm 65mm 80mm 100mm 125mm 150mm 200mm
Nominal sizes DN
DN Type Body PNMaterial
6–1615–50 RK 44 Cast bronze max.
225 °C
High-tempera-15–50 ture austenitic
cast steelRK 49 63–160
High-tem-65–200 perature ferritic
cast steel
15–100 RK 76 Chromium steel 6–40
125–200 RK 86 Steel /cast steel 10–40
15–100 RK 86 Stainless steel 6–40
15–200 RK 86A Austenitic steel / 10–40cast steel
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Grey cast iron /plasticPN 6 / 10 / 16
Please order these sizes as RK 41
Grey cast ironPN 6 / 10 / 16
Grey cast iron / cast bronzePN 6 / 10 / 16
8 times shorter and 5 times lighter than conventional non-return valves
1/2" 3/4" 11/4" 11/2" 21/2"
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GESTRA DISCO® Non-Return Valves RK
For industrial plants, GESTRAoffers a broad spectrum of non-return valves which aredesigned for diverse pressureratings and media.
For pressures from PN 6 to PN 40,the RK 86/86A can be used, forexample – and for the pressurerange PN 10–40 the RK 16C ofHastelloy. The RK 49 valve coversthe pressure rating up to PN 160.
Depending on the medium flowingthrough the piping of your installa-tion, a valve is then selected fromthe most suitable material. Forneutral liquids or gases, valveranges are available in the materialsbrass, bronze, steel and chromiumsteel. In the case of corrosive va-pours and gases, acids and alkalis,the versions of austenitic steel and
Hastelloy are used. For specialrequirements, e.g. in the foodstuffindustry, at low temperatures or forapplications with drinking water,valve ranges of cast bronze,austenitic steel and Hastelloy C are available.
Special features:
◗ Springs for low opening pressures
◗ Springs for reduced closing times◗ Springs for applications at high
temperatures◗ Soft seats◗ Antistatic connection◗ Pickled, free of oil and grease◗ Special connections
RK 76 The standard valve com-pletely of stainless steel atthe price level of carbon steel
RK 86 and 86Awith patented universal centering. Asstandard unit, it fits between flanges forPN 6–40, Class 150 / 300 andalso between BS10 flanges.Body material: stainless (RK86) or austenitic steel (RK 86A).Valve disc: austenitic steel
RK 16Awith self-centering body, PN 10 to 40,DN 15 to 100 ( 1/2 to 4").Facings suitable for counter-flanges to ASME 150 RF,ASME 300 RF, tongue flangesto DIN 2512 or male flangesto DIN 2513. Material:austenitic steel
RK 49 with spiral centering, for hightemperatures, PN 63 / 100 /160, DN 15 to 200 ( 1/2 to 4"). Material: high-temperatureaustenitic cast steel / high-temperature cast steel
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For every application,GESTRA gives you the optimum valve
Centering ◗
With specialcentering ring or,for the RK 86 andRK 86A, centeringthrough the body
Valve disc ◗
Austenitic steel, metal-to-metal or soft seat
Tightness
Thanks to special machining,the degree of tightness lieswell within the tolerancespermitted in DIN 3230
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Antistatic connection ◗
Standard for RK 86 and RK 86A
Guiding ◗
Four guide ribs are used toensure low-wear operation.From DN 125 (5"), the valvecone is guided by a spindle/sleeve arrangement
Springs ◗
Different springspermit variation of theopening pressure tomeet the operatingrequirements.Material: austeniticsteel, Nimonic orInconel
Spring cap ◗
The special shape always guaranteesa centralized positioning of the spring.Material: austenitic steel
Body ◗
Diverse materialsand two overalllengths, complieswith DIN EN 558-1,series 49 and DIN EN 558-2,series 52
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GESTRA DISCO® Non-Return Valves RK 86 and 86A
Our experience gives you the quality,our visions give you the innovativeenergy. On this foundation, GESTRAhas developed a non-return valvefor industrial applications thatcombines many requirements in asingle valve – and therefore not onlyfulfils but also far surpasses yourwishes and expectations.
Patented centering
The new centering mechanism ofthe RK 86/86A (patents pending)functions directly through the bodyitself. It has four integrated guideribs arranged so that, independentlyof the flange standard, the valvedisc of the RK 86/86A always liesagainst two of the guide ribs. Thenon-return valves of othermanufacturers are fitted with onlythree guide ribs at best, whichmeans that the valve disc,depending on installation, usuallyonly has contact with one of them.
All international standards
Whether for DIN, ASME or BSflange, this new DISCO non-returnvalve is prepared for all internationalstandards.
Low wear
Since the new RK 86/86A lies onnot just one but two guide ribs, therate of wear is halved – making forlong service life. What is more,jamming and canting of the valvedisc is then hardly possible. The risk of failure in your plant is thusreduced to a minimum.
DIN PN 16
ASME Class 150
BS 10 J
Non-return valves ofOTHER manufacturers
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The versatile, robustand reliable valve for all internationalstandards
The new wide contactsurfaces
They ensure optimum, uniformpressure at the flange sealingsurfaces (at both inlet and outlet),so that you can rely on trouble-freeplant operation.
The benefits in detail
1. Low wearthrough assured contact on two ribs
2. Cost savingsthrough the long extension of service life
3. Better guidance of the valve discthrough the four guide ribs integrated into the body
4. Optimum tightnessthrough the new wide contact surfaces
5. More reliabilitythrough standard threaded antistatic connection
6. Easy installationthrough the simple body centering
7. Lower inventory coststhrough the more versatile range of applications
8. For all standardsmeets DIN, ASME and BS standards
Standard antistatic connection
Antistatic connections are demand-ed, especially in the chemicalindustry, for certain parts of the plantto prevent any accumulation of staticcharge. The RK 86/86A range forDN 15–100 (1/2–4") with the standardthreaded hole meets this require-ment. For the DN 125–200 (5–8"),this threaded connection is providedon request.
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GESTRA DISCO® Non-Return Valves RK
Valve types
For the sector of heating, ventingand air-conditioning, various non-return valves are available for a widerange of requirements. The RK 70is a low-noise non-return valve, soyou see what your heating systemgives you but do not hear it. Qualityat low cost is offered by the RK 71,whilst the RK 41 is our universaland flexible valve satisfying diverserequirements in HVAC technology.Or do you need a valve for a
drinking water system, in which nobrass may be used? Or onesuitable for low temperatures? Thenyou should take the RK 44. And ifthe call is for a valve which must bescrewed into the pipe – a solution is provided even for thiscase with the MB 14.
RK 70with spiral centeringPN 6, body materialhot-pressed brass,valve disc of PPO
RK 71 with spiral centeringPN 6 to PN 16, body material hot-pressed brass, valve disc of austeniticsteel
RK 41 with spiral centeringPN 6 to PN 16, bodymaterial special brass, valve disc ofaustenitic steel
RK 44with spiral centeringPN 6 to PN 16, bodymaterial bronze, valve disc of austeniticsteel
MB 14Screwed 1/2 –2" BSP,body material hot-pressed brass, valve disc of austeniticsteel
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Listen for a minute ...no, you don’t hear a thing. It’s the low-noise RK 70!
Centering ◗
Serves asinstallation aid for centredmounting
Valve disc ◗
Austenitic steel, metal-to-metal seat. RK 41 and RK 44 can alternatively beprovided with a soft seat
Tightness
The degree of tightness lieswell within the tolerancespermitted in DIN 3230
◗
Body ◗
Wafer-type valvefor DIN, BS orASME flanges
Guiding ◗
Four guide ribs are used toensure low-wear operation.From DN 125 (5"), the valvecone is guided by a spindle/sleeve arrangement
Springs ◗
Using different springsfor the RK 41 and RK44 permits variation ofthe opening pressureto meet the operatingrequirements
Spring cap ◗
The special shape always guarantees a centralized positioning of the spring.Material: austenitic steel
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GESTRA Gravity Circulation Checks SBO
These check valves are used forpreventing gravity circulation inheating and hot-water systems.
With its three SBO types, GESTRAoffers the right gravity circulationcheck for every pump connection.All SBO types are fitted with amanual opening device. The SBO11 and SBO 21 valves can replacethe isolating valve in the supply line.These valves remain in the lineshould the pump have to be re-moved or exchanged. The benefit:the plant need no longer be com-pletely emptied.
Functional principle
Gravity circulation checks functionlike non-return valves. If a pressuredifference is generated, i.e. if thepressure before the closing elementis stronger than the pressure down-stream of the element, then thegravity circulation check opens. De-pending on how strong the volumeflow of the water is, the valve openseither partly or completely. As soonas the opening force decreases and the closing force is greater, the gravity circulation check closesagain.
Gravity circulation checkSBO 11 DN 1", 11/4", PN 6• Valve inlet with collar
for fitting a union nut• Valve outlet with
female thread
Gravity circulation checkSBO 21 DN 1", 11/4", PN 6• Valve inlet with collar
for fitting a union nut• Valve outlet with
male thread
Gravity circulation checkSBO 31 DN 3/4", 1", 11/4", PN 6• Valve inlet with female
thread for direct connec-tion to circulating pump
• Valve outlet with male thread
Picture left:Pump running, normal operation
Picture bottom left:Pump stationary, SBO preventinggravity circulation
Picture bottom right: Forced opening of the valve withmanual device
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Pumps can be re-placed without havingto empty the plant
Connections ◗
GESTRA gravity circula-tion checks are availablewith connections meetingall installation require-ments. Available designswith either male or femalethread for PN 6, 1–2" BSP
Spring opening pressure ◗
The spring forces are adapted to the special use of the valve as gravity circula-tion checks and positivelyprevent gravity circulation
Guiding
The guide resists wear and is corrosion-resistant.Jamming and canting of thevalve cone are excluded
Manual opening device
All GESTRA gravity circula-tion checks are fitted with amanual opening device providing gravity circulation in the event of pump failure.
◗
◗
Shut-off ◗
The use of plastic valvecones ensures quietoperation. The SBO 11 and SBO 21 valves inaddition are supplied with a seat gasket of EPDM
Tightness ◗
The choice of materials andthe careful manufactureensure tight closure of thevalve cone
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GESTRA DISCOCHECK® Dual-Plate Check Valves BB
Designed for lightness and low resistance
These GESTRA check valves are ofthe wafer type with short overalllengths. The reduced weight offerssignificant advantages for transport,stockkeeping and installation. Allthree basic types BB, CB and WBare characterized by excellenthydrodynamic properties.
Dual-plate check valves BB,DIN rangeDN 100–1200 (4–48"), PN 6–160• Wafer-type valves• Diameter to suit DIN flanges• Short overall length to DIN EN
558-1 and 558-2, series 16 (K3) for nominal pressures up to and including PN 63, higher pressures in accordance with API
• Metal-to-metal or soft seat (O-rings)• DIN materials
ASME range4–48", Class 150–900The dual-plate check valves of theASME range are supplied with:• Diameter to suit ASME flanges• Face-to-face dimensions to DIN /
ISO, from Class 600 in accordancewith API
• ASTM materials
Functional principle
Valve closedThe valve plates – with metal-to-metal or O-ring sealing – make evencontact with the seat.
Starting to openThe opening process begins with the hinge sides of the plates firstlifting off the centre pin, therebyreducing wear of the seating sur-faces by the kinematic effect.
Valve fully openThe rotary movement of the plates is limited by stop lugs to 80°.Additional hinge stop lugs ensure astable position of the plates whenfully open.
Valve closed
Starting to open
Valve fully open
BB11 G / 21 G PN 6
12 G / 22 G PN 10
14 G / 24 G PN 16
11 G / 21 G PN 6
12 G / 22 G PN 10
14 G / 24 G PN 16
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Greatest reliability withlongest life for highestsafety demands
All products available as DIN or ASME range.
Product range
Type Nominalpressure
100
BB11 G / 21 G PN 6
12 G / 22 G PN 10
14 G / 24 G PN 16
BB12 C / 22 C PN 10
14 C / 24 C PN 16
15 C / 25 C PN 25
16 C / 26 C PN 40
17 C PN 63
18 C PN 100
19 C PN 160
BB12 A / 22 A PN 10
14 A / 24 A PN 16
15 A / 25 A PN 25
16 A / 26 A PN 40
17 A PN 63
18 A PN 100
19 A PN 160
125 150 200 250 300 350 400 450 500 600 700 800 900 100012004" 5" 6" 8" 10" 12" 14" 16" 18" 20" 24" 28" 32" 36" 40" 48"
BB valves with anti-corrosion lining
Body of forgedsteel (C 22.8), dual plate ofaustenitic steel(1.4552)–10 to +450°C
Body and dual plate of austenitic steel(1.4404 / 1.4552)–100 to +550°C
Body of cast steel (GS-C 25)dual plate of cast steel (GS-C 25)–10 to +450°C
Body of grey cast iron (GG-25), dual plate of SG iron (GGG-40)Soft seat: EPDM –10 to +150°C,FPM (FKM) –10 to +200°C
Body of austenitic cast steel (1.4552)Dual plate of austenitic cast steel (1.4552)–100 to +550°C
Body of grey cast iron with LEVASINT® liningDual plates and other internals of bronze or austenitic steel –10 to +70°C
Body of grey cast iron with hard-rubber liningDual plates and other internals of bronze or austenitic steel –10 to +90°C
Optional items• Anti-corrosion linings• Special springs for very low
opening pressures• Springs for reduced closing times• Dampers for solving waterhammer
problems• Hard-faced seat• Purging plug
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The answer in tight spots
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GESTRA DISCOCHECK® Dual-Plate Check Valves BB
Valves with adjustable dampersfrom DN 200 (8")
In complex pipeline systems, majorflow decelerations may be causedwhen pumps are switched off or asa result of failures, leading to water-hammer and possibly disastrousconsequences for the plant. Ourengineers will be happy to assistyou with the correct design of thedual-plate check valves for yourinstallation.
Plant condition
1. Minor waterhammer0 < ∆p = 1 bar
Solution
Dual-plate check valve BB,standard design.
2. Clearly audible and perceptible waterhammer0 < ∆p = 3 bar
Dual-plate check valve BB,change of characteristic by fitting special springs.Waterhammer reduced by up to 40%.
3. Heavy waterhammer, pipework vibrating∆p > 3 bar
Dual-plate check valve BB,special design with patented dampers.Waterhammer reduced to zero.
Adjustable throttling orifice
Damping fluid
Optionally NBRPTFE
Acrylonitrile butadiene rubber (e.g. Perbunan)Polytetrafluoroethylene (e.g. Teflon)
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Ideal for a wide range of pressure, flow andtemperature conditions
Standard materials
For applications involving liquids,gases, vapours and corrosivemedia, and at low temperatures,there are various materials available.As an option, DISCOCHECK® dual-plate check valves can be suppliedwith various soft seats.
Anti-corrosion linings
Lined cast-iron and cast-steelvalves have been applied success-fully for many years now in sewageworks, supply and treatment plants,and for shipbuilding and offshoreinstallations.
Body/lining
Grey cast iron / hard rubber
Internals
Bronze or austeniticsteel
Grey cast iron / LEVASINT®
Bronze or austeniticsteel
PN
6, 10, 16
6, 10, 16
DN
150–1200(6–48")
150–1200(6–48")
Temperature limits
–10°C to +90°C
–10°C to +70°C
Body
Grey cast iron
Carbon steel
Austenitic steel
PN
Soft seats
6–16
DN
150–1200 (6–48")
Application
Liquids, gases, vapours,corrosive media and low temperatures
10–160 100–1200 (4–48")
Optionally EPDMFPM (FKM)
Ethylene-propylene rubberFluoro-rubber (e.g. Viton)
10–160 100–1200 (4–48")
Hard-rubberlining
Plates with O-rings of EPDM
LEVASINT® lining
Plates with O-rings of EPDM
LEVASINT® is a product of BAYER AG, Leverkusen
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5 DN
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GESTRA DISCOCHECK® Dual-Plate Check Valves BB
These high-quality dual-platecheck valves keep your runningcosts very low – by cutting thecosts for pumping power andmaintenance, and providingsafe, low-wear operation with along service life.
The low zeta value means that therequired pump output is reduced, so that you save energy and can usea pump with lower power consump-tion. Stress and wear are reducedbecause the plate halves lift off fromthe centre pin before the main open-ing action, the plates are separatelysuspended (two pivots), and twosprings are provided per plate half.Stop lugs at the plate halves, withadditional lugs on the body, limit theopening angle to 80° and ensure astable open position. As a result, along and maintenance-free productlifetime is achieved.
Installation
Installation positionDual-plate check valves BB fittedwith the corresponding springs canbe installed in any position. In almostall installation positions, a suitablechoice of springs can achievecorrect adaptation to the operatingconditions. Installation into verticalpipelines with downward flow is onlypossible with stronger springs.
CenteringBy the body.
Opening pressureThe opening pressure with standardsprings and horizontal flow is 7 mbarfor all sizes and pressure ratings. Asoptions, springs with an openingpressure of 2 mbar or 20 mbar canbe provided if required for particularoperating conditions.
Measures to be taken with turbulent flowThe turbulent flow on the pumpoutlet side can lead to an unstableposition of the valve plates andvarying opening angles. For any non-return valve, this will lead toincreased wear. A stabilizing sectionof 5 times the nominal size shouldbe provided at the pump outlet toprotect the valve from turbulence.
BB valve
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Stop lugs ◗
in the body ensure astable opening angle
Stop lugs ◗
at the plates limit theopening angles of theplate halves
Eye bolt ◗
Serves as an installation aid
Body
Wafer-type valve for DIN andASME flanges
◗
Flow arrow ◗
(Marking as per EN 19)
Closing springs ◗
Each plate is fitted with two springs
Plates ◗
Separately suspended and with independent action
Interior mounting ◗
No drill-holes to theoutside
Safe and maintenance-free – protection for high-value plants
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NAF-Check 526 822 100
NAF-Check 526 832 100
without 65–400 (21/2–18")
65–400 (21/2–18")with
NAF-Check 528 530 25 300–1000 (12–40")
NAF-Check 528 620 40
NAF-Check 528 520 25
NAF-Check 582 630 40
without40–250 (11/2–10")
300–1000 (12–40")
65–250 (21/2–10")with
NAF-Check 526 530 25 300–1000 (12–40")
GESTRA NAF Check Valves
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◗ Wafer-type valves for installation between flanges
◗ Short overall length to DIN EN 558-1, series 16
◗ For flanges to DIN, ASME and BS◗ Metal-to-metal seating◗ 3 material variants (steel, stainless
steel, high-temperature steel)
Installation position
NAF check valves are installed eitherin a horizontal line (with lifting eye ontop) or in a vertical line with the flowupwards.
This check valve is characterized byexcellent hydrodynamic properties,great tightness and low resistancecoefficients (zeta values). Thanks tothe eccentric flap hinge, low openingpressures are attained and operationis also possible without a closingspring. Stop lugs in the body ensurea defined opening angle and a stableposition when fully open.
Types
NAF-Check 526 620
PN
40
Spring Material
NAF-Check 526 520 25
NAF-Check 526 630 40
without
DN
40–250 (11/2–10")
300–1000 (12–40")
65–250 (21/2–10")with
For the pressure/temperature ratings and the precise material specifications,please see the relevantprice list.
Furthermore, we will gladly send you theproduct data sheets for the various types on request.
Steel
Stainless steel
High-temperaturesteel
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Excellent hydrodynamicproperties make this valve a winner
Stem ◗
Welded to the body;leaks are therebyexcluded
Stop lug ◗
at the body provideseffective limiting of the flap opening angle
Lifting eye ◗
Serves as installation aid
Body
Wafer-type valve for DIN andASME flanges
◗
Closing spring ◗
The flap is fitted with aspring – optionallywithout spring
Flap ◗
Great tightness with metal-to-metal seating
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GESTRA DISCOCHECK® Swing Check Valves CB and WB
Swing check valves CBDN 50–300 (2–12"), PN 6–40• DIN materials
Body• Wafer-type valve with short overall
length• Valve centred by body• Eye bolt for ease of installation
Shut-off• Circular flap• Metal-to-metal or soft seat with
recessed O-ring
Closing springs• Flap with two bow springs
Opening angle• Limited to 60° by stop lugs at the
flap hinge
Special variant CB 14DN 50–300 (2–12"), PN 6–16
Body• Wafer-type valve with short overall
length• Valve centred by body• Eye bolt for ease of installation
Shut-off• Circular flap• Soft seat (NBR)• Particularly suitable for dirty media
Without closing spring• With integral synthetic rubber
hinge
Opening angle• Limited by the pipe wall
Swing check valves WBDN 50–300 (2–12"), PN 10/16• DIN materials
Body• Wafer-type valve with short overall
length• Valve centred by outside of body• Eye bolt for ease of installation
Shut-off• Circular flap• Flange sealing surface: soft seat
with recessed O-ring
Without closing spring• With metal hinge
Opening angle• Limited to 70° by a stop lug in the
body
All CB types can be sandwiched between pipe flanges to DIN, BS and ASME.The WB types are available with body diameters to suit DIN flanges for PN 10/16.
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CB 26 PN 6/10/16/25/40 Steel /austenitic steel; from DN 100 (4") steel / SG iron: –10 to +300 °C
CB 26 A PN 6/10/16/25/40 Body and flap of austenitic steel: –10 to +450 °C
CB 14 PN 6/10/16 Body of steel / flap of NBR: –10 to +110 °C
WB 24 S PN 10/16 Bronze/bronze: –10 to +110 °C
WB 26 PN 10/16 Steel /steel: –10 to +110 °C
WB 26 A PN 10/16 Austenitic steel /austenitic cast steel: –10 to +110 °C
25
Quality that costsso little
Installation
Installation positionThe CB and WB valves are mountedin horizontal pipelines (with flaphinge or eye bolt on top) or in verti-cal pipelines with upward flow.
Installation downstream of pumpsTurbulent flow on the pump outletside causes an unstable position ofthe flap, varying opening angles andhence increased wear.
Proposal AA stabilizing section on the pumpoutlet side protects the swingcheck valve installed downstream of the pump from turbulence.
Proposal BIf the valve is fitted directly to thepump without a stabilizing section,the position of the flap’s centre ofrotation is of the utmost importanceto enable trouble-free operation.
Type
CB 24 S
Nominal pressure
PN 6/10/16
Nominal sizes DN mm (in) 50 (2) / 65 (21/2) / 80 (3) / 100 (4) / 125 (5) / 150 (6) / 200 (8) / 250 (10) / 300 (12)
Body cast bronze / internals bronze: –200 to +90 °C or without springs –200 to + 250 °C.Without springs and with soft seat of NBR: –30 to +110 °C
26
Selection and Sizing of Check Valves
It is very important to choose thecorrect non-return valve for the appli-cation, and to adapt it optimally forthe plant, in order to prevent clatterand premature wear.
A check valve provided with a springor counterweight commences open-ing when a certain static pressuredifferential – pressure upstream minuspressure downstream of the valve –has been established. This producesan opening force (pressure differen-tial x cross-sectional area of valve),acting against the closing force.When the opening force outbalancesthe closing force, the valve elementis opened (opening pressure). Thenecessary opening pressure dependson the spring tension or the weight ofthe counterweight, the position ofinstallation and the size of the checkvalve.
On start-up of a plant, first a staticpressure will build up between thepressure generator and the checkvalve. Once the opening pressurehas been reached and exceeds the
closing force, the volume flow be-gins. As a consequence, the pressureupstream of the check valve drops,so that the closing force once againoutbalances the opening force,causing the valve to close. Thisprocess will repeat itself until thevolume flow is large enough so that,because of the additional dynamicpressure differential, the closingforce is no longer great enough toclose the valve.Depending on the volume flow, thecheck valve opens either completelyor only partly. During partial open-ing, i.e. at a reduced volume flow,clatter may occur. This is producedby the impact of the valve disc, coneor flap onto the seat. It is possiblethat, instead of clatter, a high-frequency humming tone is heard.An incessant noise is a sure sign ofcheck valves sized too large; thevalve was not chosen optimally tomatch the requirements of the plant.The possibility of using a valve witha smaller nominal size is no longergiven if the pressure drop at full loadwould become too great.
Sometimes, the noise can only beheard during start-up or shut-down,or only at partial load. Then the valveis oversized only for these operatingphases, and it might be possible to solve the problem by reducingthe closing force, for example byusing a weaker spring or a reducedcounterweight. It may even bepossible to use a valve without anyspring at all – in vertical pipelineswith upward flow.
Noise is most frequently noticed inhot-water heating installations. Inthis case, it is advisable to use checkvalves with a plastic disc/cone, e.g.the GESTRA DISCO non-returnvalve RK 70.
Pressure drop chart Degree of opening
still closed slightly openCheck valve will clatter
more openClatter stillprobable
fully openNo clatterPressure drop
Vol
ume
flow
Degree of opening of a spring-assisted check valve as a function of volume flow
Process steam
Flash steam/gas
Fuel
Intermittentboiler blowdown
Blowdownreceiver
Cooling water
Electrical pressure control
Cooling water
Blowdown
Deaeratingunit
Heat exchanger
Fresh/softwater
Monitoring ofconductivity
Heatexchanger
Controlled fromthe condensate side
Mechanicaltemperaturecontrol
Electricaltemperaturecontrol
Monitoring ofturbidity
Condensatetank
Steam dryer/purifier
Boilerautomationas per TRD 604
Economizer
Flashvessel
Flash vessel
Measure-ment datafrom boilerhouse
Production measure-ment data
Sight glass
Steam trap
Non-return valve
Steam flow measurement
Steam flowmeasurement
SPECTOR control
Stack
Boiler
2
Non-Return (Check) Valves in a Steam and Condensate System
Applications
Vacuum breakerPrevents vacuum formation and damage to the vessel
Foot valve Stops the suction line from running dry when the fuel pump is switched off
Preventing backflowProtects the plant against back-flow in the event of malfunction/ failure of components
Ensuring unidirectional flowPrevents reverse running when pumps arranged in parallel are switched over
Non-return valve action for condensate line Prevents banking-up of conden-sate when the heat exchanger is off, and water hammer within the heating surfaces when the plant is started up again
Non-return valveTo ensure forced flow
Other applications not shown inthe schematic:
◗ Vent valve, relief valve◗ Overflow valve
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B
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C E E
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A few application examples
Here are a few examples forapplication using the non-returnvalves from our product range. If you need further support foryour particular requirements, wewill be happy to assist.
RK 86 (up to DN 100): solvents;coolants, cooling water; steam con-densates; neutral, alkaline andweak-acid saline solutions; ammoniaand ammonium hydroxide; causticsoda up to 20%; boric acid, fattyacids, diesel oil, heating oils
RK 86A: Pure steam* (for SIP appli-cations); drinking water; swimming-pool water; media of the foodstuffindustry* (e.g. dairies); mineral oilindustry; aggressive media such asformic acid (up to 50%), acetic acid,caustic soda (up to 50% and 50°C),phosphoric acid, nitric acid (up to50%), sulphuric acid (> 95%)
RK 16A: as for RK 86A
RK 16C: Highly aggressive mediasuch as hydrochloric acid up to10% at room temperature, sul-phuric acid in all concentrations upto 50°C, formic acid and nitric acidin all concentrations, bleaching lye,chloroacetic acid, chlorosulphonicacid, chlorine
RK 49: Applications at high pressures:steam, condensate, hydraulic oil
RK 70: Heating systems, air handling
RK 41 (up to DN 100): Heating in-stallations and district heating plants,cooling water, mineral oils, gases
MB 14: Heating plants, drinkingwater, cooling water
* For these applications, pleaseorder as pickled version
GESTRA non-return valves RK downstream of cooling water pumps GESTRA dual-plate check valves BBdownstream of bilge pumps
Your partner for theoptimum valve design of your installation
GESTRA Non-Return (Check) Valves
GESTRA GmbHMünchener Straße 77, D-28215 Bremen
P.O. Box 105460, D-28054 Bremen
Telephone +49 (0)421-3503-0
Telefax +49 (0)421-3503-393
E-mail [email protected]
Internet www.gestra.de
A Unit of Flowserve Corporation
810107-03/1002 W · © 2002 · GESTRA GmbH · Bremen · Printed in Germany
With Energy into the Future
Contents
Non-Return (Check) Valves in a Steam and Condensate System 2
Non-Return (Check) Valves in HVAC Technology 3
GESTRA DISCO® Non-Return Valves 4–7
GESTRA DISCO® Non-Return Valves RK 8–9
GESTRA DISCO® Non-Return Valves RK 86 and 86A 10–11
GESTRA DISCO® Non-Return Valves RK (HVAC) 12–13
GESTRA Gravity Circulation Checks SBO 14–15
GESTRA DISCOCHECK® Dual-Plate Check Valves BB 16–21
GESTRA NAF Check Valves 22–23
GESTRA DISCOCHECK® Swing Check Valves CB and WB 24–25
Selection and Sizing of Check Valves 26
Application Examples 27
