YOKOGAWA EJX Series - Installing Impulse Piping; 4.1 Impulse Piping Installation Precautions; 4.1 Connecting Impulse Piping to the Transmitter

  <4.InstallingImpulsePiping>
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IM01C25A01-01E
4. InstallingImpulsePiping
4.1 ImpulsePipingInstallation
Precautions
Theimpulsepipingthatconnectstheprocess
outputstothetransmittermustconveytheprocess
pressureaccurately.If,forexample,gascollectsin
aliquid-lledimpulseline,orthedrainofagas-lled
impulselinebecomesplugged,itwillnotconveythe
pressureaccurately.Sincethiswillcauseerrorsinthe
measurementoutput,selecttheproperpipingmethod
fortheprocessuid(gas,liquid,orsteam).Paycareful
attentiontothefollowingpointswhenroutingtheimpulse
pipingandconnectingtheimpulsepipingtoatransmitter.
4.1.1 ConnectingImpulsePipingtothe
Transmitter
(1) ChecktheHighandLowPressure
ConnectionsontheTransmitter(Figure4.1)
Symbols“H”and“L”havebeenplacedonthecapsule
assemblytoindicatehighandlowpressureside.With
differentialpressuretransmitters,connectthehigh
pressuresideimpulselinetothe“H”side,andthelow
pressuresideimpulselinetothe“L”side.
Withgauge/absolutepressuretransmitters,connectthe
impulselinetothe‘H’side.
F0401.ai
Process
connection
“H” and “L” are shown
Process connection
Process connector
Bolt
Differential Pressure Transmitter
Figure4.1 “H”and“L”SymbolsonaCapsule
Assembly
(2) ChangingtheProcessConnectorPiping
Connections(fordifferentialpressure
transmitters)
Theimpulsepipingconnectiondistancescanbechanged
between51mm,54mmand57mmbychangingthe
orientationoftheprocessconnectors.
Thisisconvenientforaligningtheimpulselinewitha
processconnectors.
57 mm 54 mm 51 mm
F0402.ai
Figure4.2 ProcessConnectorImpulsePiping
ConnectionDistances
(3) TighteningtheProcessConnector
MountingBolts
Afterconnectinganimpulseline,tightentheprocess
connectormountingboltsuniformly.
(4) RemovingtheImpulsePipingConnecting
PortDustproofCap
Theimpulsepipingconnectingportonthetransmitteris
coveredwithaplasticcaptokeepoutdust.Thiscapmust
beremovedbeforeconnectingtheline.(Becarefulnot
todamagethethreadswhenremovingthiscap.Never
insertascrewdriverorothertoolbetweenthecapand
portthreadstoremovethecap.)
(5) ConnectingtheTransmitterand3-Valve
Manifold(fordifferentialpressure
transmitters)
A3-valvemanifoldconsistsoftwostopvalvestoblock
processpressureandanequalizingvalvetoequalize
thepressuresonthehighandlowpressuresidesofthe
transmitter.Suchamanifoldmakesiteasiertodisconnect
thetransmitterfromtheimpulsepiping,andisconvenient
whenadjustingthetransmitterzeropoint.
Therearetwo3-valvemanifoldtyps:thepipe-mounting
typeandthedirect-mountingtype;careshouldbetaken
withrespecttothefollowingpointswhenconnectingthe
manifoldtothetransmitter.
Pipe-MountingType3-ValveManifold
F0403.ai
Nipple
Nipple
Process
connector
Ball head
lock nut
Pipe
Ball head
lock nut
Process
connector bolts
50 mm(2-inch) pipe
Pipes
3-valve
manifold
Impulse piping
Vent plug
(optional)
Stop valve
(low pressure side)
Equalizing valve
(balancing)
Stop valve
(high pressure side)
Figure4.3 3-ValveManifold(Pipe-MountingType)
InstallingImpulsePiping
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