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©2007JohnCraneInc.Pr in t02/07PipingPlansPoster

Mechanical Seal Piping Plans

Plan 72Secondary Containment Seals

Description:Plan72 forsecondarycontainment usesanexternal lowpressurebuffer gas,usuallynitrogen,regulatedbyacontrolpanelthatinjectsitintotheoutersealcavity.

Advantages:Introductionofa buffergaslike nitrogenreducesfugitiveemissions, preventsicingon coldapplications,andprovides forsomecooling totheoutboardseal.

General:Plan72isnormallyusedwithPlan75forprimarysealleakagethatiscondensing,orwith Plan76 fornon-condensingleakage.

Plan 75SecondaryContainmentSeals

Description:Plan75isacollectionsystemusedwithsecondarycontainmentseals forprocessfluid thatwillcondenseatlowertemperaturesorisalwaysinaliquidstate.

Advantages:Thecollectionreservoir containsapressuregauge anda highpressureswitch toindicateabuildupinpressurefromexcessiveprimarysealleakageor failure.

General:Plan75canbeusedinconjunctionwithagas purgefromPlan72. Typicallycontacting  secondarycontainment  sealsareusedwiththisplan.

Plan 76SecondaryContainmentSeals

Description:Plan76isasystemtodivertnon-condensingprimaryseal leakageto aflareor vaporrecoverysystem.

Advantages:Lowerinitialand maintenancecoststhandualunpressurisedseals usinga Plan52.

General:Plan76canbeusedinconjunctionwithagaspurgefromPlan72.Canbeusedwithcontactingornon-contactingcontainmentseals.

Plan 65Single Seals

Description:Plan65isaliquidleakagedetectionplannormallyusedfor singleseals.Itutilizesalevelswitchonareservoirtosetoffanalarmwhenexcess leakageis detected.

Advantages:Providesan alarmedindicationofexcessiveseal leakagethat canshutdowne quipmentifnecessary.

General:Thesystemincludes alooptoby-passtheorificetopreventhighpressure ontheatmosphericsideof theseal.Theglandthrottlebushing designshouldbe inlinewiththefluid’sproperties.

Plan 62Quench Seals

Description:Plan62isacommonplantoimprovetheenvironmentonthe atmosphericsideof singleseals byquenchingwithsteam, nitrogenorwater.

Advantages:Plan62isalowcostalternativetotandemseals.The quenchprevents orretardsproductcrystallizationorcoking.Quenches canalso providesomecooling.

General:Typicalapplications;steamquenches onhotservicesto retardcoking,nitrogenquenches oncold orcryogenicserviceto preventicing,or waterquenchto  preventcrystallizationoraccumulation of  productontheatmospheresideoftheseal.

Plan 01Single Seals

Description:Plan01 isan internalrecirculationfromthepumpdischargeareaofthepumpintothesealchamber,similartoaPlan11butwithnoexposedpiping.

Advantages:Noproductcontaminationand noexternalpiping,which isadvantageous onhighlyviscousfluidsat lowertemperaturestominimizetheriskoffreezingthatcanoccurwithexposedpiping.

General:Thisflushplanshouldonlybeusedforcleanproductsasdirtyproductscanclogtheinternalline.Not recommendedonverticalpumps.

Plan 02Single Seals

Description: Plan02is anon-circulatingflushplanwhereadequatevaporsuppressioncanbeassured.

Advantages: Solidsarenotcontinuallyintroducedintothe sealchamber,no externalhardwareisrequired,andnaturalventingoccurswhenusedwitha taperedboresealchamber.

General:Idealwithlarge bore/taperedboreANSI/ASMEB73.1or specialisedISO3069sealchambersorwith hotprocesspumps utilizingacoolingjacket.On thelatter services,aPlan 62withsteamcanalso providesomeadditionalcooling.

Plan 11Single Seals

Description:Plan11isthemostcommonflushplaninusetoday.This plantakes fluidfromthe pumpdischarge(orfroman intermediatestage)throughan orifice(s)anddirectsittothesealchambertoprovidecoolingandlubricationtothe sealfaces.

Advantages:Noproductcontaminationand pipingissimple.

General:IfthesealissetupwithaDistributedorExtendedflush,the effectivenessofthe systemwillbeimproved.

Plan 12Single Seals

Description:Plan12issimilartoPlan11,exceptthatastrainerorfilteris addedto theflushline.

Advantages:Noproductcontamination andsolids areremovedfromthe flushstreamkeeping theseal clean.

General:IfthesealissetupwithaDistributedorExtendedflush,the effectivenessofthe systemwillbeimproved.Thisplan shouldbe equippedwithadifferentialpressureindicatoror alarmtoalert theuserthatthe filterorstraineris clogged.

Plan 13Single Seals

Description:InaPlan13theflowexitsthesealchamberandisroutedbacktopumpsuction.

Advantages:WithaPlan13itispossibletoincreaseordecreaseseal chamberpressurewith propersizingof theorificeandthroat bushingclearance.

General:TypicallyPlan13 isused onverticalturbinepumpssincetheyhavethedischargeatthetopofthepumpwherethesealislocated.Becauseofthedifferenceinflow patterns,Plan13 isnot asefficientinremovingheatasaPlan11andthusrequiresahigherflowrate.

Plan 14Single Seals

Description: Plan14isacombinationofPlans11and13.Flushistakenoffofpumpdischarge,senttothesealchamber,andpipedbacktopumpsuction.

Advantages: Coolingcanbe optimizedwiththeflushdirectedatthe sealfaces. Planallowsfor automaticventingofthe sealchamber.

General: Oftenused onverticalpumpstoprovideadequate flowandvapor pressuremarginindependentofthroat bushingdesign.

Plan 53BDual Seals,  Pressurised

Description:Plan53B previouslytermed53Modifiedusesan accumulatortoisolate thepressurisinggasfrom thebarrierfluid.A heatexchangeris includedinthe circulationlooptocoolthebarrierfluid.Flowisinducedbyapumpingring.

Advantages:Shouldtheloop becontaminatedforany reason,thecontaminationis containedwithintheclosed circuit.Themake-up systemcansupply barrierfluidto multipledualpressurisedsealingsystems.

General:Thebladderaccumulatorisolatesthepressurisinggasfrom thebarrierfluidtoprevent gasentrainment.Theheatexchangercanbewatercooled,finnedtubing, oranair-cooledunitbased uponthesystemheat load.

Plan 52Dual Seals, Unpressurised

Description:Plan52usesanexternalreservoirtoprovide bufferfluidfor theoutersealof anunpressuriseddualsealarrangement.

Advantages:Incomparisonto singleseals,dualunpressurised sealscanprovidereducednet leakageratesaswellasredundancyintheeventoffailure.

General:Coolingcoilsin thereservoirareavailablefor removingheatfrom thebufferfluid.

Plan 41Single Seals

Description:Plan41isacombinationofPlan21andPlan31.InPlan41,productfrompumpdischargeisfirstputthroughanabrasiveseparatorandthentotheheatexchanger beforebeingintroduced tothesealchamber.

Advantages:Solidsareremoved andproducttemperatureisreduced toenhance theseal’senvironment.

General:Plan41istypicallyusedonhotserviceswithsolids;however,dependingon thetemperatureof theprocess,operatingcosts canbe high.

Plan 32Single Seals

Description:Plan32usesaflushstreambroughtinfromanexternalsourcetotheseal.Thisplanisalmostalwaysused inconjunctionwith aclose clearancethroatbushing.

Advantages:Theexternalflush fluid,whenselectedproperly,canresult invastlyextended seallife.

General:Whenanoutsideflushsource isused,concernsregardingproductdilutionand/oreconomicsmustbeconsideredbytheuser.

Plan 31Single Seals

Description:Plan 31 is variation ofPlan 11,where an abrasive separatoris added to the flushline.In this plan,the product is introduced to theabrasive separatorfrom the discharge ofthe pump.

Advantages: Unlikeastraineror filter,theabrasiveseparatordoesnotrequirecleaning.Solidsareremovedfromtheflush streamkeepingthesealclean.

General: Thisplanshouldbeusedfor servicescontainingsolidsthat haveaspecificgravityatleasttwicethatof theprocessfluid.Typicallytheseparatorrequiresa minimumpressuredifferentialof15psi (1bar) tooperateproperly.Highpressuredifferentialsmayrequiretheadditionofanorificeupstreamof thecyclone.

Plan 23Single Seals

Description:Plan23isaclosedloopsystemusingapumpingringto circulateproductthrough aheatexchangerandbacktothesealchamber.

Advantages:MoreefficientthanaPlan21andlesschanceof heatexchanger fouling.Reduced temperatureimproveslubricityand improvesvaporpressure margin.

General:Preferredplanfor hotapplications.Closeclearancethroatbushing isrecommendedto reducemixingofhot productwithcooler closedloop system.

Plan 21Single Seals

Description:Plan21isacooledversionofPlan11.Theproductfrom pumpdischargeis directedthroughanorifice,thento aheat exchangerto lowerthetemperaturebeforebeingintroduced intothe sealchamber.

Advantages:Processfluidcools andlubricatestheseal,thereforeno dilutionofprocess stream.Coolingimproveslubricityand reducesthe possibilityofvaporizationinthe sealchamber.

General:Plan21isnotapreferredplan,eitherbyAPIormanyusers,duetothehighheatloadputontheheatexchanger.APlan 23is preferred.

Plan 53A Dual Seals, Pressurised

Description:Plan53Ausesanexternalreservoirtoprovide barrierfluidforapressuriseddualseal arrangement.Reservoirpressureis producedby agas,usuallynitrogen.Flow isinducedby apumpingring.

Advantages:Reservoirsizecan beoptimizeddependenton flowrate.Wearparticlessettleto bottomofreservoir anddon’tgetrecirculated.

  General:Heatis dissipatedby  reservoircoolingcoils.Barrier  fluidissubjecttogas  entrainmentatpressures/   temperaturesabove  300psi(21barg).

Plan 53CDual Seals,Pressurised

Description:Plan53Cuses apistona ccumulatortoprovidepressuretothesystem.Itusesareferencelinefromthesealchambertoprovide aconstant pressuredifferentialoverthechamber’spressure.A water-orair-cooledheat exchangerprovidesforbarrierfluid cooling.Flowis inducedbyapumpingring.

Advantages:Providesa trackingsystemto maintainbarrierpressureabove sealchamber pressure.

  General: Theheatexchangercanbewater-cooled,finnedtubing,oranair-cooledunitbasedupon thesystemheat

  load.Thereference linetothe accumulator  mustbetolerant ofprocesscontamination  withoutplugging.

Plan 54Dual Seals,Pressurised

Description:Plan54 utilizesanexternalsource toprovidea cleanpressurisedbarrier fluidtoa dualpressurisedseal.

Advantages:Canprovide pressurisedflowto multiplesealinstallationsto reducecosts.Positively eliminatesfugitiveemissionsto atmosphere.

General:Plan54systemscanbecustomengineeredtosuitapplicationrequirements. Systemscan rangefromthedirectconnection fromotherprocess streamstocomplexAPI614 systems.

Plan 74Dual Gas Seals

Description:Plan74 providesa pressurisedgas,typicallynitrogen,todualgassealsthroughtheuseofacontrolpanelthat removesmoisture,filtersthe gas,andregulatesthebarrier pressure.

Advantages:Lowercostsand maintenancethansystemsused ondual pressurisedliquidsystems.Leakagetoatmosphereisaninertgas.

General:Thebarriergas isusually apressurisednitrogenline.For higherpressureapplications thesystempressurecanbesupplementedwithagaspressurebooster/amplifier.

 

PI PRESSURE INDICATOR

TITEMPERATUREINDICATOR

FI FLOW INDICATOR

FM FLOW METER

PSHPRESSURE SWITCHHIGH

PSLPRESSURE SWITCH

LOW

LI LEVEL INDICATOR

LSH LEVEL SWITCH HIGH

LSL LEVEL SWITCH LOW

FSH FLOW SWITCH HIGH

RESERVOIR

PISTON

ACCUMULATOR

COALESCING

FILTER

BLADDERACCUMULATOR

HEAT

EXCHANGER

STRAINER

ORIFICE

BLOCK VALVE

PRESSURECONTROL

VALVE

CYCLONESEPARATOR

CHECK VALVE

FLOW

REGULATINGVALVE

PipingKEY 

EuropeSlough,UKTel: 44-1753-224000Fax: 44-1753-224224

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North AmericaMortonGroveTel: 1-847-967-2400Fax: 1-847-967-3915

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FM

PI

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PI   PSH

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PI   PSLPI

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LSL

PSH

PI   PSL

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EXTERNAL

PRESSURISED

BARRIER

SOURCE/SYSTEM

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Iftheproducts featuredwillbe usedin apotentiallydangerousand/or hazardousprocess, your John Cranerepresentativeshouldbe consultedprior to

their selection anduse. In theinterestofcontinuousdevelopment, John CraneCompaniesreservetherightto alter designsand specifications without

prior notice.

©2007 John Crane Print02/07 www.johncrane.com   ISO 9001, ISO 14001, ISO/TS 16949 Certified. Detailsavailableon request. P-MSPP/Eng

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