GESTRANon-Return (Check) Valves

ForHVACsystems,sanitaryapplicationsandindustrialtechnology

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Processsteam

Flashsteam/gas

Fuel

Intermittentboilerblowdown

Blowdownreceiver

Coolingwater

Electricalpressurecontrol

Coolingwater

Blowdown

Deaeratingunit

Heatexchanger

Fresh/softwater

Monitoringofconductivity

Heatexchanger

Controlledfromthecondensateside

Mechanicaltemperaturecontrol

Electricaltemperaturecontrol

Monitoringofturbidity

Condensatetank

Steamdryer/purifier

Economizer

Flashvessel

Flashvessel

Measure-mentdatafromboilerhouse

Sightglass

Steamtrap

Non-returnvalve

Steamflowmeasurement

Steamflowmeasurement

SPECTORcontrol

Stack

Boiler

BoilerautomationasperTRD604

ProductionMeasure-

mentdata

Non-Return (Check) Valves in Steam and Condensate Systems

d Ensuring unidirectional flow preventsreverserunningwhenpumpsarrangedinparallelareswitchedover

e Non-return valve action for condensate line preventsbanking-upofcondensatewhentheheatexchangerisoff,andwaterhammerwithinthe

heatingsurfaceswhentheplantisstartedupagainf Non-return valvetoensureforcedflow

Other applications not shown in the schematic:w Ventvalve,reliefvalvew Overflowvalve

a Vacuum breakerpreventsvacuumformationanddamagetothevessel

b Foot valve stopsthesuctionlinefromrunningdrywhenthefuelpumpisswitchedoff

c Preventing backflow protectsagainstback-flowintheeventofmalfunction/failureofcomponents

b

c

cc e e

f

c

d

a

c

Non-Return (Check) Valves

Non-Return (Check) Valves in HVAC Technology

Boiler

Feedflow

Returnflow

RK

Returnline

Burnerwithpump

Boiler

Safety return flow

Safety feed flow

Feedflow

Returnflow

Mixer

RK,SBO

Standbytank

Solarcollector

Boiler

Ensuring unidirectional flowpreventsreverserunningwhenpumpsarrangedinparallelareswitchedover

Foot valvestopsthesuctionlinefromrunningdrywhenthepumpisswitchedoff

Gravity circulation checkpreventscirculationcausedbygravity

Preventing backflowprotectsthepumpagainstback-flowafteritisswitchedoff

GESTRAGravityCirculationChecksSBO . . . . . . . . . . . . . . . . . . . . . . 4–5

GESTRADISCO®Non-ReturnValves . . . . . . . . . . . . . . . . . 6–9

GESTRADISCO®Non-ReturnValvesRK . . . . . . . . . . . . . 10–13

GESTRADISCO®Non-ReturnValvesRK86and86A . . . 14–15

GESTRADISCOCHECK®Dual-PlateCheckValvesBB . . . . . . . . 16–�1

GESTRANAFCheckValves . . . . . . . . . . . . . . . . . . . ��–�3

GESTRADISCOCHECK®SwingCheckValvesCBandWB . . . . . �4–�5

SelectionandSizingofCheckValves . . . . . . . . . . . . . . . . . . . . �6

ApplicationExamples . . . . . . . . . . . . . . . . �7

Contents

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Gravity circulation check SBO 11DN 1“ , 1 1/4“, PN 6w Valve inlet with collar

for fitting a union nutw Valve outlet with

female thread

GESTRA Gravity Circulation Checks SBO

Pump running, normal operation Pump stationary, SBO preventing gravity circulation

These check valves are used for preventing gravity circulation in heating and hot-water systems.

WithitsthreeSBOtypes,GESTRAofferstherightgravitycirculationcheckforeverypumpconnec-tion .AllSBOtypesarefittedwithamanualopen-ingdevice .TheSBO11andSBO�1valvescanreplacetheisolatingvalveinthesupplyline .Thesevalvesremaininthelineshouldthepumphavetoberemovedorexchanged .Thebenefit:theplantneednolongerbecompletelyemptied .

Functional principle

Gravitycirculationchecksfunctionlikenon-returnvalves .Ifapressuredifferenceisgenerated,i .e .ifthepressurebeforetheclosingelementisstrongerthanthepressuredown-streamoftheelement,thenthegravitycirculationcheckopens .Depend-ingonhowstrongthevolumeflowofthewater

Forced opening of the valve with manual device

Gravity circulation check SBO 21 DN 1“, 1 1/4“, PN 6w Valve inlet with collar

for fitting a union nutw Valve outlet with male

thread

Gravity circulation check SBO 31 DN 3/4“, 1“, 1 1/4“, PN 6w Valve inlet with

female thread for direct connection to circulating pump

w Valve outlet with male thread

is,thevalveopenseitherpartlyorcompletely .Assoonastheopeningforcedecreasesandtheclos-ingforceisgreater,thegravitycirculationcheckclosesagain .

Non-Return (Check) Valves

Connections w

GESTRA gravity circulation checks are available with connections meeting all installation requirements. Available designs with either male or female thread for PN 6, 1–2" BSP

Spring opening pressure w

The spring forces are adapted to the special use of the valve as gravity circulation checks and positively prevent gravity circulation

Guiding

The guide resists wear and is corrosion-resistant. Jamming and canting of the valve cone are excluded

Manual opening device

All GESTRA gravity circulation checks are fitted with a manual opening device providing gravity circulation in the event of pump failure.

w

w

Shut-off w

The use of plastic valve cones ensures quiet operation. The SBO 11 and SBO 21 valves in addition are supplied with a seat gasket of EPDM

Tightness w

The choice of materials and the careful manufacture ensure tight closure of the valve cone

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Today GESTRA can look back with pride on one hundred years of experience in valve manu-facture. The company offers a broad range of DISCO® non-return valves tailored to fulfil the most diverse of applications and customer requirements.

Allvalvesaremadeofdiversematerialstomeetparticulardemands,andtheindividualvalvecom-ponentsareoptimallycoordinatedwitheachother .

Throughthisidealmixtureofdifferentcomponentsintherangeofstandardvalves,thebestvalvecanbedeliveredforalmosteveryapplication .Hereitdoesnotmatterwhetherathermallycriticalapplicationmustbesafeguarded,orwhethera

GESTRA DISCO® Non-Return Valves

non-returnvalvemustbedesignedforoperationinoxygen,forexample .ItisevenpossibletomanufacturetheDISCO®valve,whichhasprovenitsworthamilliontimesover,inaspecialmaterialtoanswerspecificneeds .AllGESTRAnon-returnvalvesareofthewafertypeandhaveextremelyshortoveralllengths .Thankstotheirexcellentdesignandhydrodynamicfeatures,thesevalvesofferclearadvantagesoverconventionaltypes:

w Compactdesignw Lowweightw Mountinginanypositionw Lowinstallationcostsw Widechoiceofmaterialsw Space-savingstockkeepingw Safeoperationofindustrialplantsw Lowpressuredrop

ThenameGESTRAisaguaranteeofhighmanu-facturingqualityfortheGESTRADISCO®non-returnvalves .

Non-Return (Check) Valves

GESTRA DISCO® non-return valve in the fully open state

Functional principle

Thespring-assistedDISCO®non-returnvalveopenswhentheopeningforceexceedstheclosingforce .Theopeningforcedependsonthepressureorthevolumeflow,andtheclosingforceonthetensionoftheclosingspring,ontheclosingweight,ontheinstallationpositionandthesizeofthenon-returnvalve .

Installation

GESTRADISCO®non-returnvalvescanbeinstalledinanyposition,withthesoleexceptionofthevalvessuppliedwithoutaspring .Thesevalvescanonlybeinstalledinverticallineswithupwardflow .

GESTRA DISCO® non-return valve in the closed state

GESTRA DISCO® non-return valve with spiral centering, DN 15–100 ( 1/2–4“)

GESTRA DISCO® non-return valve with self-centering body, DN 15–100 ( 1/2–4“)

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Connections of your choice

ForflangestoDINEN109�-1,formB1/B�/D/F,toASMERF/RJ,ortoworksstandards

Materials

DIN/EN and ASTM:w Hot-pressedbrassw Specialbrassw Castbronzew Greycastironw High-temperatureferriticcaststeelw Stainlesssteel/caststeelw Austeniticsteel/caststeelw High-temperatureausteniticcaststeelw HastelloyCSpecialmaterialsavailableonrequest .

GESTRA DISCO® Non-Return Valves

Tight shut-off

GESTRAnon-returnvalvesaretestedaccordingtoDINEN1��66-1,withwaterorairasthemedium .ThiscorrespondstotheoutdatedDIN3�30,part3,testspecifications“BN”(tightnesstestwithwater)and“BO”(tightnesstestwithair) .

Forvalveswithasoftseat,valuescorrespondingtoleakagerateAareachieved(BN1/BO1) .

Short overall length, low weight

Valveswithshortface-to-facedimensionsreducetheweightandsizeofaplant .Asthefigurebelowdemonstrates,theoveralllengthofaGESTRAnon-returnvalveisonly1/8thatofaconventionalnon-returnvalve .TheoveralllengthscomplywithDINEN558-1and558-�,series49and5�(K4/K5) .

Thewaferdesigndrasticallyreducestheweightincomparisonwithconventionalvalves .AGESTRAnon-returnvalveofstainlesssteelinDN�00weighs�3kg,whilsttheweightofthecorrespond-ingconventionaltypeis1�0kg!

Nominal width DN Overall lenght L in mm mm in Series 49 Series 52

15 1/2 16 25 20 3/4 19 31.5 25 1 22 35.5 32 11/4 28 40 40 11/2 31.5 45 50 2 40 56

65 21/2 46 63 80 3 50 71 100 4 60 80

125 5 90 110 150 6 106 125 200 8 140 160

Non-Return (Check) Valves

Valve type Nominal sizes DNValves with soft seat

Non-returnvalvesprovidedwithametallicdiscarealsoavailableonrequestwithasoftseatmadeof:w EPDM(ethylene-propylenerubber)suitable

forwaterandsteam,–40to+150°C .w FPM(fluoro-rubber)formineraloilandgases,

–�5to+�00°C .w PTFE(Teflon)forcorrosivemedia,–190to

+�50°C .

CE

TheproductscomplywiththerequirementsoftheEUPressureEquipmentDirective97/�3/EC .Classifiedforusewithfluidsofgroup1and/or�(dangerousandnon-dangeroussubstances) .Somenominalsizesfallundertheexceptionrule(Article3 .3)andthereforemaynotbearanyCEmarking .

Forfurtherinformation,pleaseseeourPriceList .

RK 70

RK 71

RK 41

RK 44

RK 44S

RK 76

RK 86

RK 86A

RK 16A

RK 29A

RK 49

RK 16C

Hot-pressedbrass/valvediscofplasticFor flanges PN 6 / 10 / 16Heatinginstallationsupto100°C,compressed-airsystems

Hot-pressedbrass/valvediscofausteniticsteelFor flanges PN 6 / 10 / 16Heatinginstallations,highertemperatures

Specialbrass/valvediscofausteniticsteelPN 6 / 10 / 16Liquids,gases,vapours/forindustrialandheatingplants

Castbrass/valvediscofausteniticsteelPN 6 / 10 / 16Liquids,gases,vapours

CastbronzePN 6 / 10 / 16Seawateranddrinkingwater

Chromiumsteel/valvediscofausteniticsteelPN 6 / 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFLiquids,gases,vapours/forindustrialandheatingplants

Stainlesssteel/valvediscofausteniticsteelPN 6 / 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFLiquids,gases,vapours/highcorrosionresistance

AusteniticsteelPN 6 / 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFCorrosiveliquids,gases,vapours,acids,alkalis

AusteniticsteelPN 10 / 16 / 25 / 40 – ASME Class 150 / 300 RFCorrosiveliquids,gases,vapours,acids,alkalis

AusteniticsteelPN 63 / 100 / 160 / 250 / 320 / 400 – ASME CL. 400 – 2500Liquids,gases,vapours/highcorrosionresistance

High-temperatureausteniticcaststeelPN 63 / 100 / 160Liquids,gases,vapoursathightemp .(upto450°C)

HastelloyCorequivalentnickelalloysPN 10 / 16 / 25 / 40Particularlycorrosivemedia

PleaseorderthesesizesasRK41

PleaseorderthesesizesasRK86 A

Greycastiron/plasticPN 6

GreycastironPN 6 / 10 / 16

Greycastiron/castbronzePN 6 / 10 / 16

Steel/caststeelPN 10 / 16 / 25 / 40

Aust .steel/aust .caststeelPN 10 / 16 / 25 / 40

Onrequest

High-temperatureferriticcaststeelPN 63 / 100 / 160

15 20 25 32 40 50 65 80 100 125 150 200

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CastbronzePN 6 / 10 / 16

Austeniticsteel

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1/2" 3/4" 1" 11/4" 11/2" 2" 2 1/2" 3" 4" 5" 6" 8"

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GESTRA DISCO® Non-Return Valves RK

Valve types

Forthesectorofheating,ventingandair-condi-tioning,variousnon-returnvalvesareavailableforawiderangeofrequirements .TheRK70isalow-noisenon-returnvalve,soyouseewhatyourheatingsystemgivesyoubutdonothearit .QualityatlowcostisofferedbytheRK71,whilsttheRK41isouruniversalandflexiblevalvesatisfyingdiverserequirementsinHVACtechnology .Ordoyouneedavalveforadrinkingwatersystem,inwhichnobrassmaybeused?Oronesuitableforlowtemperatures?ThenyoushouldtaketheRK44 .TheRK44Sisrecommendedforseawater,drinkingwaterandswimming-poolwater .Andifthecallisforavalvewhichmustbescrewedintothepipe–asolutionisprovidedevenforthiscasewiththeMB14 .

RK 70with spiral centering PN 6, body material hot-pressed brass, valve disc of PPO

RK 71 with spiral centering PN 6 to PN 16, body material hot-pressed brass, valve disc of austenitic steel

RK 41 with spiral centering PN 6 to PN 16, body material special brass, valve disc of austenitic steel

MB 14Screwed 1/2–2" BSP,body material hot-pressed brass, valve disc of austenitic steel

RK 44with spiral centering PN 6 to PN 16, body material bronze, valve disc of austenitic steel

RK 44Swith spiral centering PN 6 to PN 16. Body material: bronze. Valve disc: bronze

Non-Return (Check) Valves

Spring cap w

The special shape always guarantees a centralized positioning of the spring. Material: austenitic steel

Guiding w

Four guide ribs are used to ensure low-wear operation. From DN 125 (5"), the valve cone is guided by a spindle/ sleeve arrangement

Tightness

The degree of tightness lies well within the tolerances permitted in DIN EN 12266-1

Body w

Wafer-type valve for DIN/EN, BS or ASME flanges

w

Centering w

Serves as installation aid for centred mounting

Valve disc w

Austenitic steel, metal-to-metal seat. RK 41 and RK 44 can alternatively be provided with a soft seat

Springs w

Using different springs for the RK 41 and RK 44 permits variation of the opening pressure to meet the operating requirements

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GESTRA DISCO® Non-Return Valves RK

For industrial plants, GESTRA offers a broad spectrum of non-return valves which are designed for diverse pressure ratings and media.

ForpressuresfromPN6toPN40,theRK86/86Acanbeused,forexample–andforthepressurerangePN10–40theRK16CofHastelloy .TheRK49coversthepressureratingsuptoPN160andtheRK�9AthepressureratingsPN63–400 .

Dependingonthemediumflowingthroughthepipingofyourinstallation,avalveisthenselectedfromthemostsuitablematerial .Forneutralliquidsorgases,valverangesareavailableinthemateri-alsbrass,bronze,steelandchromiumsteel .Inthecaseofcorrosivevapoursandgases,acidsandalkalis,theversionsofausteniticsteelandHastelloyareused .Forspecialrequirements,e .g .inthefoodstuffindustry,atlowtemperaturesorforapplicationswithdrinkingwater,valverangesofcastbronze,austeniticsteelandHastelloyCareavailable .

Special features:

w Springsforlowopeningpressuresw Springsforreducedclosingtimesw Springsforapplicationsathigh

temperaturesw Softseatsw Antistaticconnectionw Pickled,freeofoilandgrease/siliconew Specialconnectionsw Blinddrilling

RK 86 und 86 Awith patented universal centering. As standard unit, it fits between flanges for PN 6–40, Class 150 / 300 and also between BS10 flanges. Body material: stainless (RK 86) or austenitic steel (RK 86A). Valve disc: austenitic steel

RK 76 The standard valve com-pletely of stainless steel at the price level of carbon steel

RK 16Awith self-centering body, PN 10 to 40, DN 15 to 100 (1/2 to 4"). Facings suit- able for counterflanges to ASME 150 RF, ASME 300 RF, tongue flanges to DIN 2512 or male flanges to DIN 2513. Material: austenitic steel

RK 29Awith self-centering body, PN 63 to 160 (PN 400 on request), Class 400 to 1500 (Class 2500 on request). Material: austenitic steel

RK 49 with spiral centering, for high temperatures, PN 63 / 100 / 160, DN 15 to 200 (1/2 to 4"). Material: high-temperature austen-itic cast steel / high-temperature cast steel

Non-Return (Check) Valves

Spring cap w

The speacial shape always guarantees a centralized positioning of the spring. Material: austenitic steel

Guiding w

Four guide ribs are used to ensure low-wear operation. From DN 125 (5"), the valve cone is guided by a spindle/ sleeve arrangement

Tightness

Thanks to special machining, the degree of tightness lies well within the tolerances permitted in DIN EN 12266-1

Antistatic connection w

Standard for RK 86 and RK 86A

Body w

Diverse materials and two overall lengths, complies with DIN EN 558-1, series 49 and DIN EN 558-2, series 52

w

Centering w

With special centering ring or, for the RK 86 and RK 86A, centering through the body

Valve disc w

Austenitic steel, metal-to-metal or soft seat

Springs w

Different springs permit varia-tion of the opening pressure to meet the operating require-ments. Material: austenitic steel, Nimonic or Inconell

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All international standards

WhetherforDIN/EN,ASMEorBSflange,thisnewDISCO®non-returnvalveispreparedforallinter-nationalstandards .

Low wear

SincethenewRK86/86Aliesonnotjustonebuttwoguideribs,therateofwearishalved–makingforlongservicelife .Whatismore,jammingandcantingofthevalvediscisthenhardlypossible .Theriskoffailureinyourplantisthusreducedtoaminimum .

GESTRA DISCO® Non-Return Valves RK 86 and 86 A

Ourexperiencegivesyouthequality,ourvisionsgiveyoutheinnovativeenergy .Onthisfounda-tion,GESTRAhasdevelopedanon-returnvalveforindustrialapplicationsthatcombinesmanyrequirementsinasinglevalve–andthereforenotonlyfulfilsbutalsofarsurpassesyourwishesandexpectations .

Patented centering

ThepatentedcenteringmechanismoftheRK86/86A(patentspending)functionsdirectlythroughthebodyitself .Ithasfourintegratedguideribsarrangedsothat,independentlyoftheflangestandard,thevalvediscoftheRK86/86Aalwaysliesagainsttwooftheguideribs .Thenon-returnvalvesofothermanufacturersarefittedwithonlythreeguideribsatbest,whichmeansthatthevalvedisc,dependingoninstallation,usuallyonlyhascontactwithoneofthem .

DIN / EN PN 16

ASME Class 150

BS 10 JNon-return valves of OTHER manufacturers

Non-Return (Check) Valves

The new wide contact surfaces

Theyensureoptimum,uniformpressureattheflangesealingsurfaces(atbothinletandoutlet),sothatyoucanrelyontrouble-freeplantoperation .

Standard antistatic connection

Antistaticconnectionsaredemanded,especiallyinthechemicalindustry,forcertainpartsoftheplanttopreventanyaccumulationofstaticcharge .TheRK86/86ArangeforDN15–100(1/�–4“)withthestandardthreadedholemeetsthisrequire-ment .FortheDN1�5–�00(5–8“),thisthreadedconnectionisprovidedonrequest .

The benefits in detail

1. Low wear throughassuredcontactontworibs

2. Cost savings throughthelongextensionofservicelife

3. Better guidance of the valve disc throughthefourguideribsintegrated

intothebody

4. Optimum tightness throughthenewwidecontactsurfaces

5. More reliability throughstandardthreadedantistatic

connection

6. Easy installation throughthesimplebodycentering

7. Lower inventory costs throughthemoreversatilerange

ofapplications

8. For all standards meetsDIN/EN,ASMEandBSstandards

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Dual-plate check valves BB

DIN rangeDN50–1�00(�–48”),PN6–160w Wafer-typevalvesw DiametertosuitDINflangesw ShortoveralllengthtoDINEN558-1and558-�,

series16(K3)fornominalpressuresuptoandincludingPN63,higherpressuresinaccord-ancewithAPI

w Metal-to-metalorsoftseat(O-rings)w DINmaterials

ASME range�–48”,Class150–900Thedual-platecheckvalvesoftheASMErangearesuppliedwith:w DiametertosuitASMEflangesw Face-to-facedimensionstoDIN/ISO,

fromClass600inaccordancewithAPIw ASTMmaterials

Functional principle

Valve closedThe valve plates – with metal-to-metal or O-ring sealing – make even contact with the seat.

Starting to openThe opening process begins with the hinge sides of the plates first lifting off the centre pin, thereby reducing wear of the seating surfaces by the kinematic effect.

Valve fully openThe rotary movement of the plates is limited by stop lugs to 80°. Additional hinge stop lugs ensure a stable position of the plates when fully open.

Designed for lightness and low resistance

TheseGESTRAcheckvalvesareofthewafertypewithshortoveralllengths .Thereducedweightofferssignificantadvantagesfortransport,stockkeepingandinstallation .AllthreebasictypesBB,CBandWBarecharacterizedbyexcellenthydrodynamicproperties .

GESTRA DISCOCHECK® Dual-Plate Check Valves BB

Non-Return (Check) Valves

Product range

Type 50 65 100 125 150 200 250 300 350 400 450 500 600 700

BB 11G/�1G PN6

1�G/��G PN10

14G/�4G PN16

BB 1�C/��C PN10

14C/�4C PN16

15C/�5C PN�5

16C/�6C PN40

17C PN63

18C PN100

19C PN160

BB 1�A/��A PN10

14A/�4A PN16

15A/�5A PN�5

16A/�6A PN40

17A PN63

18A PN100

19A PN160

BB 11G/�1G PN6

1�G/��G PN10

14G/�4G PN16

11G/�1G PN6

1�G/��G PN10

14G/�4G PN16

BB valves with anti-corrosion lining

Bodyofcaststeel(GS-C�5)Dualplateofcaststeel(GS-C�5)–10to+400°C

Bodyofausteniticcaststeel(1 .4408)Dualplateofausteniticcaststeel(1 .4408)–�00to+550°C

BodyC�� .8Dualplate1 .4006–10to+400°C

Bodyanddualplateofausteniticsteel(1 .4404)–�00to+550°C

Bodyofgreycastironwithhard-rubberliningDualplatesandotherinternalsofbronzeorausteniticsteel–10to+90°C

BodyofgreycastironwithVESTOSINT®liningDualplatesandotherinternalsofbronzeorausteniticsteel–10to+80°C

AllproductsavailableasDIN/ENorASMErange .Nominalsizes900,1000and1�00onrequest .

Optional itemsw Anti-corrosionliningsw Specialspringsforverylowopeningpressuresw Springsforreducedclosingtimes

w Dampersforsolvingwaterhammerproblemsw Hard-facedseatw Purgingplugw GasketsofEPDM,FPM,NBRandPTFE

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Availableonrequest

Nominal pressure 2" 2 1/2" 4" 5" 6" 8" 10" 12" 14" 16" 18" 20" 24" 28"3"

Bodyofgreycastiron(GG-�5)DualplateofSGiron(GGG-40)FPM(FKM)–10to+300°C

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GESTRA DISCOCHECK® Dual-Plate Check Valves BB

Valves with adjustable dampers from DN 200 (8“)

Incomplexpipelinesystems,majorflowdecelera-tionsmaybecausedwhenpumpsareswitchedofforasaresultoffailures,leadingtowaterhammerandpossiblydisastrousconsequencesfortheplant .Ourengineerswillbehappytoassistyouwiththecorrectdesignofthedual-platecheckvalvesforyourinstallation .

Plant condition

1 . Minorwaterhammer0<∆p≤1bar

� .Clearlyaudibleandperceptiblewaterhammer0<∆p≤3bar

3 .Heavywaterhammer,pipeworkvibrating∆p>3bar

Solution

Dual-platecheckvalveBB,standarddesign .

Dual-platecheckvalveBB,changeofcharacteristicbyfittingspecialsprings .Waterhammerreducedbyupto40% .

Dual-platecheckvalveBB,specialdesignwithpatenteddampers .Waterhammerreducedtozero .

Adjustable throttling orifice

Damping fluid

Non-Return (Check) Valves

Standard materials

Forapplicationsinvolvingliquids,gases,vapoursandcorrosivemedia,andatlowtemperatures,therearevariousmaterialsavailable .Asanoption,DISCOCHECK®dual-platecheckvalvescanbesuppliedwithvarioussoftseats .

Anti-corrosion linings

Linedcast-ironandcast-steelvalveshavebeenappliedsuccessfullyformanyyearsnowinsewageworks,supplyandtreatmentplants,andforship-buildingandoffshoreinstallations .

VESTOSINT®liningsareusede .g .fordrinkingwaterandseawater,rubberliningsfore .g .seawaterandwastewater .

Body

GreycastironCarbonsteelAusteniticsteell

Soft seats

Optionally EPDM FPM(FKM)

Optionally NBR PTFE

PN DN Application

6–16 150–1�00(6–48") Liquids,gases,vapours,10–160 100–1�00(4–48") corrosivemedia10–160 100–1�00(4–48") andlowtemperatures

Ethylene-propylenerubber –40°Cto+150 °CFluoro-rubber(e .g .Viton) –�5°Cto+�00 °C

Acrylonitrilebutadienerubber(e .g .Perbunan) –30°Cto+110°CPolytetrafluoroethylene(e .g .Teflon) –�5°Cto+�00°C

Body/ lining

Greycastiron/hardrubber

Greycastiron/VESTOSINT®

Internals PN DN Temperature limits

Bronzeor 6,10,16 150–1�00 –10°Cbis+90°Causteniticsteel (6–48")

Bronzeor 6,10,16 150–1�00 –10°Cbis+80°Causteniticsteel (6–48")

Hard-rubber lining

Plates with O-rings of EPDM

VESTOSINT® lining

Plates with O-rings of EPDM

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Installation

Installation positionDual-platecheckvalvesBBfittedwiththecorres-pondingspringscanbeinstalledinanyposition .Inalmostallinstallationpositions,asuitablechoiceofspringscanachievecorrectadaptationtotheoperatingconditions .Installationintoverticalpipelineswithdownwardflowisonlypossiblewithstrongersprings .

CenteringBythebody .

Opening pressureTheopeningpressurewithstandardspringsandhorizontalflowis7mbarforallsizesandpres-sureratings .Asoptions,springswithanopeningpressureof�mbaror�0mbarcanbeprovidedifrequiredforparticularoperatingconditions .

Measures to be taken with turbulent flowTheturbulentflowonthepumpoutletsidecanleadtoanunstablepositionofthevalveplatesandvary-ingopeningangles .Foranynon-returnvalve,thiswillleadtoincreasedwear .Astabilizingsectionof5timesthenominalsizeshouldbeprovidedatthepumpoutlettoprotectthevalvefromturbulence .

These high-quality dual-plate check valves keep your running costs very low – by cutting the costs for pumping power and mainte-nance, and providing safe, low-wear operation with a long service life.

Thelowzetavaluemeansthattherequiredpumpoutputisreduced,sothatyousaveenergyandcanuseapumpwithlowerpowerconsumption .Stressandweararereducedbecausetheplatehalvesliftofffromthecentrepinbeforethemainopen-ingaction,theplatesareseparatelysuspended(twopivots),andtwospringsareprovidedperplatehalf .Stoplugsattheplatehalves,withadditionallugsonthebody,limittheopeningangleto80°andensureastableopenposition .Asaresult,alongandmaintenance-freeproductlifetimeisachieved .

GESTRA DISCOCHECK® Dual-Plate Check Valves BB

5 DN

BB valve

Non-Return (Check) Valves

Eye bolt

Serves as an installation aid

Body

Wafer-type valve for DIN/EN and ASME flanges

Flow arrow

(Marking as per EN 19)

w

w

w

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Stop lugs w

in the body ensure a stable opening angle

Stop lugs w

at the plates limit the opening angles of the plate halves

Closing springs w

Each plate is fitted with two springs

Plates w

Separately suspended and with independent action

Interior mounting w

No drill-holes to the outside

��

Installation position

NAFcheckvalvesareinstalledeitherinahorizontalline(withliftingeyeontop)orinaverticallinewiththeflowupwards .

Thischeckvalveischaracterizedbyexcellenthydrodynamicproperties,greattightnessandlowresistancecoefficients(zetavalues) .Thankstotheeccentricflaphinge,lowopeningpressuresareattainedandoperationisalsopossiblewithoutaclosingspring .Stoplugsinthebodyensureadefinedopeningangleandastablepositionwhenfullyopen .

w Wafer-type valves for installation between flanges

w Short overall length to DIN EN 558-1, series 16

w For flanges to DIN/EN, ASME and BSw Metal-to-metal seatingw 3 material variants (steel, stainless steel,

high-temperature steel)

GESTRA NAF Check Valves

NAF-Check5�68�� 100

NAF-Check5�683� 100

without 65–400 (�1/�–18")

65–400 (�1/�–18")with

NAF-Check5�8530 �5 300–1000(1�–40")

NAF-Check5�86�0 40

NAF-Check5�85�0 �5

NAF-Check58�630 40

without40–�50 (11/�–10")

300–1000 (1�–40")

65–�50 (�1/�–10")with

NAF-Check5�6530 �5 300–1000 (1�–40")

Types

NAF-Check5�66�0

PN

40

Spring Material

NAF-Check5�65�0 �5

NAF-Check5�6630 40

without

DN

40–�50 (11/�–10")

300–1000 (1�–40")

65–�50 (�1/�–10")with

Forthepressure/tem-peratureratingsandtheprecisematerialspecifi-cations,pleaseseetherelevantpricelist .

Furthermore,wewillgladlysendyoutheproductdatasheetsforthevarioustypesonrequest .

Steel

Stainless steel

High-temperature steel

Non-Return (Check) Valves

Lifting eye

Serves as installation aid

Body

Wafer-type valve for DIN/EN and ASME flanges

w

w

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Closing spring w

The flap is fitted with a spring – optionally without spring

Stem w

Welded to the body; leaks are thereby excluded

Flap w

Great tightness with metal-to-metal seating

Stop lug w

at the body provides effective limiting of the flap opening angle

�4

Swing check valves CB

w DN50–300(�–1�"),PN6–40w DIN/ENmaterials

Bodyw Wafer-typevalvewithshortoveralllengthw Valvecentredbybodyw Eyeboltforeaseofinstallation

Shut-offw Circularflapw Metal-to-metalorsoftseatwith

recessedO-ring

Closing springsw Flapwithtwobowsprings

Opening anglew Limitedto60°bystoplugsatthe

flaphinge

Special variant CB 14

w DN50–300(�–1�"),PN6–16

Bodyw Wafer-typevalvewithshortoveralllengthw Valvecentredbybodyw Eyeboltforeaseofinstallation

Shut-offw Circularflapw Softseat(NBR)w Particularlysuitablefordirtymedia

Without closing springw Withintegralsyntheticrubberhinge

Opening anglew Limitedbythepipewall

Swing check valves WB

w DN50–300(�–1�"),PN10/16w DIN/ENmaterials

Bodyw Wafer-typevalvewithshortoveralllengthw Valvecentredbyoutsideofbodyw Eyeboltforeaseofinstallation

Shut-offw Circularflapw Flangesealingsurface:softseatwith

recessedO-ring

Without closing springw Withmetalhinge

Opening anglew Limitedto70°byastopluginthebody

GESTRA DISCOCHECK® Swing Check Valves CB and WB

All CB types can be sandwiched between pipe flanges to DIN/EN, BS and ASME. The WB types are available with body diameters to suit DIN flanges for PN 10/16.

Non-Return (Check) Valves

Proposal AAstabilizingsectiononthepumpoutletsideprotectstheswingcheckvalveinstalleddownstreamofthepumpfromturbulence .

Installation

Installation positionTheCBandWBvalvesaremountedinhorizontalpipelines(withflaphingeoreyeboltontop)orinverticalpipelineswithupwardflow .

Installation downstream of pumpsTurbulentflowonthepumpoutletsidecausesanunstablepositionoftheflap,varyingopeninganglesandhenceincreasedwear .

Proposal BIfthevalveisfitteddirectlytothepumpwithoutastabilizingsection,thepositionoftheflap’scentreofrotationisoftheutmostimportancetoenabletrouble-freeoperation .

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CB�6 PN6/10/16/�5/40 Steel/austeniticsteel;fromDN100(4“)steel/SGiron:–10to+300°C

CB�6A PN6/10/16/�5/40 Bodyandflapofausteniticsteel:–10to+450°C

CB14 PN6/10/16 Bodyofsteel/flapofNBR:–10to+110°C

WB�4S PN10/16 Bronze/bronze:–10to+110°C

WB�6 PN10/16 Steel/steel:–10to+110°C

WB�6A PN10/16 Austeniticsteel/austeniticcaststeel:–10to+110°C

Type

CB�4S

Nominal pressure

PN6/10/16 Bodycastbronze/internalsbronze:–�00to+90°Corwithoutsprings–�00to+�50°C .WithoutspringsandwithsoftseatofNBR:–30to+110°C

(50 / 65 / 80 /100 /125 /150 /200 /250 /300) (2" / 2 1/2" / 3" / 4" / 5" / 6" / 8" / 10" / 12")

Nominal sizes DN

�6

Sometimes,thenoisecanonlybeheardduringstart-uporshut-down,oronlyatpartialload .Thenthevalveisoversizedonlyfortheseoperatingphases,anditmightbepossibletosolvetheprob-lembyreducingtheclosingforce,forexamplebyusingaweakerspringorareducedcounterweight .Itmayevenbepossibletouseavalvewithoutanyspringatall–inverticalpipelineswithupwardflow .

Noiseismostfrequentlynoticedinhot-waterheatinginstallations .Inthiscase,itisadvisabletousecheckvalveswithaplasticdisc/cone,e .g .theGESTRADISCO®non-returnvalveRK70 .

flowbegins .Asaconsequence,thepressureupstreamofthecheckvalvedrops,sothattheclosingforceonceagainoutbalancestheopeningforce,causingthevalvetoclose .Thisprocesswillrepeatitselfuntilthevolumeflowislargeenoughsothat,becauseoftheadditionaldynamicpres-suredifferential,theclosingforceisnolongergreatenoughtoclosethevalve .

Dependingonthevolumeflow,thecheckvalveopenseithercompletelyoronlypartly .Duringpar-tialopening,i .e .atareducedvolumeflow,clattermayoccur .Thisisproducedbytheimpactofthevalvedisc,coneorflapontotheseat .Itispossiblethat,insteadofclatter,ahigh-frequencyhummingtoneisheard .Anincessantnoiseisasuresignofcheckvalvessizedtoolarge;thevalvewasnotchosenoptimallytomatchtherequirementsoftheplant .Thepossibilityofusingavalvewithasmallernominalsizeisnolongergivenifthepressuredropatfullloadwouldbecometoogreat .

Itisveryimportanttochoosethecorrectnon-returnvalvefortheapplication,andtoadaptitoptimallyfortheplant,inordertopreventclatterandprematurewear .

Acheckvalveprovidedwithaspringorcounter-weightcommencesopeningwhenacertainstaticpressuredifferential–pressureupstreamminuspressuredown-streamofthevalve–hasbeenestablished .Thisproducesanopeningforce(pres-suredifferentialxcross-sectionalareaofvalve),actingagainsttheclosingforce .Whentheopeningforceoutbalancestheclosingforce,thevalveele-mentisopened(openingpressure) .Thenecessaryopeningpressuredependsonthespringtensionortheweightofthecounterweight,thepositionofinstallationandthesizeofthecheckvalve .

Onstart-upofaplant,firstastaticpressurewillbuildupbetweenthepressuregeneratorandthecheckvalve .Oncetheopeningpressurehasbeenreachedandexceedstheclosingforce,thevolume

Selection and Sizing of Check Valves

Pressure drop

Volu

me

flow

Pressure drop chart Degree of opening

still closed slightly open – Check valve

will clatter

more open – Clatter still

probable

fully open – No clatter

Degree of opening of a spring-assisted check valve as a function of volume flow

Non-Return (Check) Valves

RK 16A:asforRK86A

RK 16C:Highlyaggressivemediasuchashydro-chloricacidupto10%atroomtemperature,sulphu-ricacidinallconcentrationsupto50°C,formicacidandnitricacidinallconcentrations,bleachinglye,chloroaceticacid,chlorosulphonicacid,chlorine

RK 49:Applicationsathighpressures:steam,con-densate,hydraulicoil

RK 70:Heatingsystems,airhandling

RK 41 (up to DN 100):Heatinginstallationsanddistrictheatingplants,coolingwater,mineraloils,gases

MB 14:Heatingplants,drinkingwater,coolingwater

*Fortheseapplications,pleaseorderaspickledversion

Here are a few examples for application using the non-return valves from our product range. If you need further support for your particular requirements, we will be happy to assist.

RK 86 (up to DN 100):solvents;coolants,coolingwater;steamcondensates;neutral,alkalineandweak-acidsalinesolutions;ammoniaandammo-niumhydroxide;causticsodaupto�0%;boricacid,fattyacids,dieseloil,heatingoils

RK 86A: Puresteam*(forSIPapplications);drink-ingwater;swimming-poolwater;mediaofthefoodstuffindustry*(e .g .dairies);mineraloilindustry;aggressivemediasuchasformicacid(upto50%),aceticacid,causticsoda(upto50%and50°C),phosphoricacid,nitricacid(upto50%),sulphuricacid(>95%)

A few application examples

GESTRA dual-plate check valves BB downstream of bilge pumps

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GESTRA AGMünchenerStr .77,D-�8�15BremenP .O .Box105460,D-�8054BremenTelephone +49(0)4�1-3503-0Telefax +49(0)4�1-3503-393E-mail gestra .ag@flowserve .comInternet www .gestra .de

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