Download - Non-Return (Check) Valves
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
Indu
stria
l Tec
hnol
ogy
Heat
ing,
ven
ting,
sa
nita
ry a
nd a
ir-co
nditi
onin
g
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 o�ers a broad spectrum of non-return valves which are designed for diverse pressure ratings and media.
For pressures from PN 6 to PN 40, the RK 86/86A can be used, for example – and for the pressure range PN 10–40 the RK 16C of Hastelloy. The RK 49 covers the pressure ratings up to PN 160 and the RK 29A the pressure ratings PN 63–400.
Depending on the medium �owing through the piping of your installation, a valve is then selected from the most suitable material. For neutral liquids or gases, valve ranges are available in the materi-als brass, bronze, steel and chromium steel. In the case of corrosive vapours and gases, acids and alkalis, the versions of austenitic steel and Hastelloy are used. For special requirements, e.g. in the foodstu� industry, at low temperatures or for applications with drinking water, valve ranges of cast bronze, austenitic steel and Hastelloy C are available.
Special features:
w Springs for low opening pressuresw Springs for reduced closing timesw Springs for applications at high
temperaturesw Soft seatsw Antistatic connectionw Pickled, free of oil and grease / siliconew Special connectionsw Blind drilling
RK 86 und 86 Awith universal centering. As standard unit, it �ts between �anges for PN 6–40, Class 150 / 300 and also between BS10 �anges. 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 counter �anges to ASME 150 RF, ASME 300 RF, tongue �anges to DIN 2512 or male �anges 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
Whether for DIN/EN, ASME or BS �ange, this new DISCO® non-return valve is prepared for all inter-national standards.
Low wear
Since the new RK 86/86A lies on not just one but two guide ribs, the rate of wear is halved – making for long service life. What is more, jamming and canting of the valve disc is then hardly possible. The risk of failure in your plant is thus reduced to a minimum.
GESTRA DISCO® Non-Return Valves RK 86 and 86 A
Our experience gives you the quality, our visions give you the innovative energy. On this founda-tion, GESTRA has developed a non-return valve for industrial applications that combines many requirements in a single valve – and therefore not only ful�ls but also far surpasses your wishes and expectations.
Unique centering
The centering mechanism of the RK 86/86A functions directly through
the
body
itself . It has four integrated guide ribs
arranged
so that, independently of the �ange standard, the valve disc of the RK 86/86A always lies
against two of the guide ribs. The non-return valves of other manufacturers are �tted with only three guide ribs at best, which means that the valve disc, depending on installation, usually only has contact with one of them.
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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80
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“)
In complex pipeline systems, major �ow decelera-tions may be caused when pumps are switched o� or as a result of failures, leading to waterhammer and possibly disastrous consequences for the plant. Our engineers will be happy to assist you with the correct design of the dual-plate check valves for your installation.
Plant condition
1. Minor waterhammer 0 < ∆p ≤ 1 bar
2. Clearly audible and perceptible waterhammer
0 < ∆p ≤ 3 bar
3. Heavy waterhammer, pipework vibrating ∆p > 3 bar
Solution
Dual-plate check valve BB, standard design.
Dual-plate check valve BB, change of characteristic by �tting special springs. Waterhammer reduced byup to 40%.
Dual-plate check valve BB, special design with dampers . Waterhammer reduced to zero.
Adjustable throttling ori�ce
Damping �uid
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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