Data Sheet

Bulletin 71.1:CSB400
7
Pressure Registration and Downstream
Control Line Connection
Internal Registration
CSB400Seriesregulatorswithan“IT”or“IN”inthe
typenumberhaveinternalpressureregistration.
Internalregistrationutilizesaninternalsensetube
locatedintheoutletofthebodytocommunicatethe
outletpressuretotheactuatorchamber.Internal
registrationisusedforeaseofinstallation.Response
timeoftheregulatorisnotasquickasdualregistration
duetointernalsenseonlyhavingonesensingport
feedingtheactuatorchamber.
Dual Registration
CSB400Seriesregulatorswithan“DT”or“DN”inthe
typenumberhavedualpressureregistration.Dual
registrationutilizesbothinternalsenseandanexternal
downstreampressureregistrationline(controlline)
connected to the 3/4 NPT control line tapping in the
lowerdiaphragmcasing.Byprovidingtwochannels
ofpressurecommunicationtotheactuator,dual
registrationprovidesthebestmethodofpressure
registrationforapplicationsthatexhibitquickchanging
loads.RefertotheCSB400SeriesInstructionManual
forinstructionregardingdownstreamcontrolline
installation.TheTypeVSX4slam-shutandIntegral
Monitorhaveexternalpressureregistrationonlyand
requiredownstreamcontrollineinstallation.One
exceptionexistswhenthePrimaryregulatorisinstalled
onaRp1x2-1/4GAZbody,thentheTypeVSX4slam-
shuthastheoptionofinternalpressureregistration.
External Registration
CSB400Seriesregulatorswithan“ET”or“EN”in
thetypenumberhaveexternalpressureregistration.
Externalregistrationutilizesablockedthroat,an
O-ringstemseal,anda3/4NPTcontrollinetapping
inthelowerdiaphragmcasing,Figure3.Aregulator
withadownstreamcontrollineistypicallyusedfor
monitoringinstallationsorotherapplicationswhere
thereisanequipmentinstalledbetweentheregulator
andthepressurecontrolpoint.TheO-ringstemseal
separatesthebodypressurefromdiaphragmcase
pressureonmonitorinstallationswhereleakagecannot
betolerated.RefertotheCSB400SeriesInstruction
Manualforinstructionregardingdownstreamcontrol
lineinstallation.TheTypeVSX4slam-shutandIntegral
Monitorhaveexternalpressureregistrationonlyand
requiredownstreamcontrollineinstallation.One
exceptionexistswhenthePrimaryregulatorisinstalled
onaRp1x2-1/4GAZbody,thentheTypeVSX4slam-
shuthastheoptionofinternalpressureregistration.
Internal Token Relief
CSB400Seriesregulatorswitha“T”inthetype
number,providealowcapacityortokeninternalreliefto
helpminimizeoverpressure.Thetokenreliefalsoacts
toavoidnuisancetripsoftheslam-shutmechanism
duetopressureincreasefromthermalexpansionor
overpressurecausedbyoricedamagesuchasnicks
and dents.
Overpressure Protection
Overpressuringanyportionofaregulatoror
associatedequipmentmaycausepersonalinjury,
leakageorpropertydamageduetoburstingof
pressure-containingpartsorexplosionofaccumulated
gas. Provide appropriate pressure relieving to ensure
thatthecriticallimitsintheSpecicationsectionare
notexceeded.Regulatoroperationwithinratingsdoes
notpreventthepossibilityofdamagefromexternal
sourcesorfromdebrisinthepipeline.
The CSB400 Series regulators have outlet pressure
ratings that are lower than their inlet pressure ratings.
Apressurerelievingorpressurelimitingdeviceis
neededfortheCSB400Seriesthatdonothavean
IntegralMonitororslam-shutdeviceinstalled,ordo
nothaveaseparateupstreammonitoringregulator
installedsuchastheTypeCSB410.
TypesCSB403andCSB423provideanintegral
True-Monitor™installedontheinletsideofthebodythat
servestocontroldownstreampressureiftheprimary
regulatorceasestocontroldownstreampressure.
TypesCSB404,CSB424andCSB454regulatorsrely
onTypeVSX4slam-shutdeviceforoverpressure
protection.Intheeventthatoutletpressurerisesabove
orfallsbelowthepressuresettingoftheTypeVSX4,
theslam-shutdevicewillactivateortrip,thereby
stoppingowthroughtothedownstreamsystem.To
restartowtothedownstreamsystem,theTypeVSX4
mustbereset.TypeCSB404regulatorswitha“T”
intheirtypenumberprovidealowcapacity(Token)
internalreliefwhichprovidessufcientrelieftopreclude
theTypeVSX4trippingduetopressurerisecaused
bythermalexpansionoroverpressureduetoorice
damagesuchasnicksanddents.
TypesCSB410andCSB430aremonitorregulators
installedupstreamofthePrimaryregulator.Anexternal
controllineisconnecteddownstreamofthePrimary
regulatortoprovideprotectionifthePrimaryregulator
wouldceasetocontroldownstreampressure.
TypesCSB414andCSB434regulatorsactin
thesamemannerastheTypesCSB410and
CSB430describedpreviously,however,theyalso
provide additional overpressure protection to the