Data Sheet

Bulletin 71.1:CSB400
9
Figure 6. Type CSB404ET Externally Registered Regulator and Slam-Shut Operational Schematic
Type CSB404ET Regulator with Token Relief and Slam-shut
M1146
April 2008
Type CSB404
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
M1146
OPSO ADJUSTING SCREW
UPSO ADJUSTING SCREW
UPSO SPRING
SCREW
SLAM-SHUT
ORIFICE
OPSO SET SPRING
RESET KNOB
SLAM-SHUT DISK
VENT
REGULATOR
CONTROL SPRING
REGULATOR
ADJUSTING SCREW
REGULATOR ORIFICE
VALVE STEM
LEVER
EXTERNAL CONTROL
LINE (SENSE LINE)
TOKEN RELIEF
SPRING
TYPE VSX4 SLAM-SHUT MODULE PRIMARY REGULATOR
PROXIMITY
SWITCH PLUG
abackuporicedevice,whichsealsonasecondary
seatingsurfaceshouldtheprimaryoriceseatingsurface
ordiskbecomedamaged.
TheIntegralTrue-Monitor™isexternallyregisteredand
willrequireadownstreamcontrolline.Iftheprimary
regulatorhasinternalregistration,themonitorwillstill
requireanexternalcontrollineforpressureregistration.
Token Relief
Anoptionaltokenreliefmaybeinstalledonthe
primaryregulatoroftheTypeCSB403,denotedbythe
“T”inthetypenumber,forexample,TypeCSB403ET.
Thetokenreliefwillbeactivatedwhenthepressure
risesandactivatesthemonitoringregulatorinorder
toprovideanindicationthatthemonitoriscontrolling
owinsteadoftheprimaryregulator.
Type VSX4 Slam-Shut Device
TheTypeVSX4slam-shutdeviceontheTypeCSB404
regulatorisafastactingshutoffdevicethatprovides
overpressure (OPSO) or over and underpressure
(OPSO/UPSO)protectionbyshuttingofftheowof
gastothedownstreamsystem.TheTypeVSX4’s
actionsareindependentoftheTypeCSB404regulator
andofvariationstotheinletpressure.TheTypeVSX4
usesexternalpressureregistrationandrequiresa
downstreamcontrollineregardlessiftheregulatoris
internallyorexternallyregistered.
RefertotheCSB400SeriesInstructionManual
forinstructionregardingdownstreamcontrolline
installation.TheTypeVSX4slam-shuthasanexternal
pressureregistrationonlyandrequires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.
RefertoFigures6and7,shutoffdiskisnormally
locatedintheopen(reset)position.Ifthepressure
belowthediaphragmincreases(ordecreases)
reachingtheTypeVSX4setpoint,thediaphragmwill
travel upwards (or downwards) to release the trip
mechanismwhichallowsthespringforceonthestem
willpushthestemanddiskagainsttheseat,shutting
offallgasow.Themanualresethasaninternal
bypasstoequalizetheresetpressureoneitherside
ontheshutoffdisk.
InorderfortheUnderpressureShutoff(UPSO)of
anyslam-shuttobetriggered,thedownstreampipe
pressuremustdropbelowtheUPSOsetpoint.Inthe
caseofadownstreamlinebreak,numerousfactors
canpreventthedownstreampipepressurefrom
decreasingbelowtheslam-shutUPSOsetpoint.These
factorsincludethedistanceofpipetothebreak,the
diameterofthepipe,sizeofthebreakandthenumber
ofrestrictions,suchasvalves,elbowsandbends,
downstreamoftheregulatorand/orslam-shutdevice.
Duetothesefactorsadditionalprotectionsshouldbe
installedtostopowintheeventofalinebreak.