Honeywell HON P095NG Series - Operating and Measuring Lines

Basicsforinstallingthedeviceinapipe
UsermanualforHONR100gaspressureregulatorwithHONP095NGpilot  29
4.3 Operatingandmeasuringlines
Thelinesmustbearrangedandsizedinsuchawaythatthedevices’intendedfunctionwillbe
ensured.
 Measuringline
 Themeasuringlinetransmitsthepressureprocessvaluefromthesensing
pointtothemeasuringdiaphragmofacontrollerorthepilotofagaspressure
regulatororsafetyreliefvalveortothemeasuringdiaphragmofthemoni‐
toringdeviceofaslam‐shutdevice.Itneedstobeconnectedtothepipe
sidewaysorupwardsseparatelyforeachdevice.Inthecaseofsafetyequip‐
ment,themeasuringlinemustbeconnectedupstreamofthefirstoutlet‐side
shut‐offdeviceinsuchawaythatitcannotbeshutoff.Ifthemeasuringlineis
additionallyconnecteddownstreamofthefirstoutlet‐sideshut‐offdevice,
3‐wayballvalveswithnegativeoverlapmustbeusedforswitching.Theseball
valvesdonothaveavalvepositioninwhichbothmeasuringlinescanbefully
closedatthesametime.
 Ventline
 Theventlineisusedtoconnectameasuringdiaphragmtotheatmosphere.If
themeasuringunitbecomesdamaged(e.g., diaphragmrupture),itcanstart
conveyinggas.Undercertainoperatingconditions,andfollowingconsultation
withthemanufacturer,ventlinescanbeomittedifventvalves(HON 915)or
safetydiaphragmconfigurationscanbeusedinstead.
 Blowdownline
 Theblowdownlineinasafetyreliefvalveisusedtodivertgas(leakinggas,
for example)intotheatmosphere. 
Groupingventlinesorblowdownlines(intoaheader)ispermissibleifitdoesnothavea
negativeimpactontheindividualdevices’operation.Withinthiscontext,itisrecommended
tohavethecross‐sectionalareaoftheheaderbeatleastfivetimesaslargeasthetotalofthe
individuallines’cross‐sectionalareas. 
Forprimaryslam‐shutdevices,itisrecommendedtoroutetheslam‐shutdevices’ventlines
separately.Ventlinesmustnotbegroupedtogetherwithblowdownlines.
 Dischargingline
 Whenusingindirectacting(pilot‐operated)slam‐shutdevices,thedischarg‐
inglineisusedtodiverttheexhaustgasfromthepilotintothesystem’sout‐
letchamber.Oncertaindevices,thedischarginglinewillbegroupedwiththe
feedbackline. 
 Feedbackline
 Whenusingindirectacting(pilot‐operated)slam‐shutdevices,
thefeedback
lineisusedtoreturntheoutletpressuretotheactuator.
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Connectionlinesbetween
deviceandgasregulating
line