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Pilot OperatedPressure Relief Valves(POPRV)October 2020 Chief Inspectors MeetingPrepared by: J. F. Ball1

Objectives 2Definition/ ManufacturersBasic OperationFlowing Pilot vs Non-Flowing PilotSnap / Pop Action PilotModulating PilotASME Code StatusApplicationsFeatures/Benefits (and Concerns)Code UpdatesOptions

Definition(PTC-25) pilot-operated PRV: a pressure relief valve inwhich the disk is held closed by systempressure, and the holding pressure iscontrolled by a pilot valve actuated by systempressure.3

ManufacturersAnderson GreenwoodDresserFarrisTarget Rock (nuclear)MercerTaylor ValveLeserApparecchiWeir Power4

Early Pilot Valve Usage5

Basic OperationPilotMain Valve6The Pilot controls the MainValve action of:- Opening Pressure- Closing Pressure- Style Of Action

Basic OperationDomePiston SealSeatPistonBelow set pressure, force imbalance due to differential areakeeps main valve closed7

Basic OperationPDPD 0.70P1P1Above set pressure with Main Valve open8

Standard Main Valve(AG Valve Series 200, 400, 500 and 800)CapPistonSealPistonRetainerScrewTube FittingCap BoltDome SpringLock PinLinerSeat RetainerSeatNozzleRetainerBodyTube FittingNozzle SealRed Indicates Leak Path9Pilot Tube

Flowing vs. Non-Flowing PilotFlowing Pilot –When the mainvalve is open andflowing, there issystem fluidflowing throughthe pilot.Non-Flowing Pilot –When the main valve isopen, there is nosystem fluid flowingthrough the pilot.10

Main Valve Action Based on Pilot StylePopMain Valve FullyOpen at SetPressureMain Valve Piston Lift100% Lift3%MinimumBlowdownSetPressureModulatingMain Valve OpensAccordingto Relief Demand11Main Valve Piston Lift100% LiftPressure

Pop Action Pilot (Series 200) Pop Action Pilot (snap action) Gas or Mixed Phase Service Non flowing pilot design(no hydrates formed)Hydrates are solids thatcontain water.12

Series 200(Normally Closed Position)DomeDomePilotPilotDischargeSet PressureAdjustmentRelief SeatBlowdownSeatSystemBlowdownAdjustment13

Series 200(Relieving Position)Dome0%100% ofsetSystem14

Series 200(Re-Closed Position)BlowdownPressureDomeRelief SeatBlowdownSeatBlowdown PressureSystemBlowdownAdjustment15

Series 200 POPRV (Pop Pilot)Main Valve DomeVolume DischargedThrough VentExamples:1F2, 0.0005 ft32J3, 0.0019 ft34P6, 0.0145 ft36R8, 0.0543 ft38T10, 0.0973 ft3Less than 1/2 a shot16ApproximateOperating Time toFull Lift for GasExamples:1F2, 0.14 second2J3, 0.19 second4P6, 0.47 second6R8, 0.77 second8T10, 1.13 second

3% MinimumBlowdownSet0Pressure17ClosingOpening100% LiftMain Valve Piston LiftDown Force On Main Valve PistonSeries 200 POPRVSet0Pressure

Series 200 POPRV Pop Action with Full Lift at Set Pressure For Gas and Mixed Phase Services(Up to 1/3 Liquid by Volume) Set Pressures 25 to 10,000 psig [1.72 To 690 barg] Temperatures -423 to 550ºF [-252 to 287ºC] Main Valve Tight to Set Pressure Minimum Pilot Cracking Pressure:100 psig [6.90 barg] and Above: 95% Of SetBelow 100 psig [6.90 barg]: 90% Of Set Range of Blowdown Adjustment: 3 To 15% Of Set Pressure(Below 5% Only with Remote Sensing) Pilot Must Vent to Atmospheric Pressure(Bug Screen or Tube to a Sump)18

Series 200 POPRV Benefits Allows Higher System Operating Pressure for MaximizedProcess Output Non-Flowing Pilot Design Minimizes Flow Through the Pilot andIngress of Particulates Minimum Pilot Venting — Only the Main Valve Dome VolumeExample: 2J3 0.0019 ft3 [0.00005 m3] No Emissions While Valve Closed Safe, Externally Adjustable Blowdown Set Pressure and Lift Unaffected by Back Pressure Protection Against Resonant Chatter19

Modulating Pilot (Series 400) Modulating Action Gas, Liquid, or Mixed Phase Non flowing pilot design20

Series 400 PilotsDiaphragm Style15 to 740 psig [1.03 To 51.03 barg](Check mfg. PistonPiston Style100 to 1480 psig[6.90 to 102 barg]21

Series 400 Pilots AdvantagesDiaphragm StylePiston StyleBest SensitivityMore RuggedBest RepeatabilityBetter Able toTolerate PressurePulsations andHigher PressuresWider Selectionof Soft Goods22

Series 400 POSRV(Normally Closed Position)Inlet SeatSet PressureAdjustmentSpoolSense DiaphragmDomeOutlet SeatPilot Discharge TubedTo Main Valve OutletFeedback Piston23Balancing Seal

Series 400 POSRV(At or Slightly Above Set Pressure, Main Valve Modulating)24

Series 400 POPRV(Above Set Pressure and at Full Lift)25

93%"Null"Position0SetPressure26100% Lift95% Set Pressure,MinimumMain Valve Piston LiftDown Force On Main Valve PistonSeries 400 POPRV0SetPressure

Series 400 POPRV Modulating Action, with the Main Valve Opening according to theRelief Demand. Opens Only Enough to Keep the System at SetPressure - - - Similar to Back Pressure Regulator Consistent Operation Regardless of Process Phase State Set Pressures 15 to 1480 psig [1.03 To 102.1 barg] Temperatures -65 to 550ºF [-54 To 286ºC] Main Valve Tight to Set Pressure Minimum Pilot Cracking Pressure: 95% of Set Pilot Is Balanced Against Back Pressure. The Discharge Is Connectedto Main Valve Outlet as Standard Set Pressure and Lift Unaffected by Back Pressure27

Series 400 POPRV Benefits Less Wasted/Lost Product ( ) No Emissions Minimized Releases and Pollution Less Noise Greater System Output by Being Able to Operate Nearer to SetPressure Set Pressure and Lift Unaffected by Back Pressure No PRV Chatter Due to Poor Inlet Piping(Caution: Check valve capacity using flowing pressure)28

Code Status Capacity certifiedand available withASME CodeDesignator forSections I, III, andVIII. Certified fluidsinclude steam,air/gas andliquid.29

Code Status Two nameplates required– one on pilot and one onmain valve with ASMEsymbol Dual fluid certificationavailable for Section Ieconomizers using CodeCase 2446 (steam andwater) Pilot sensing line to beprotected from freezing(PG-73.2.12)30

Code Status Initial capacitytests may be doneusing the mainvalve only, alongwith operationaltests to provefunction and lift31

Testing of PilotsDome Pressure GaugePilotSupply (System PressureGauge)Pilot SupplyMetering ValveNitrogen OrAir SupplyVent Valve32TD-1 Test Drum

Applications ConsiderationsThere are several things you have to consider whenselecting a pilot operated relief valve:Type of service:Air, gas, vapor, liquid, steam, etc.Temperature:-420 F to 500 F (depending on type of pilot).Set Pressure:Low Pressure: inches of water to 50 psig,diaphragm type main valve.High Pressure: 20 psig to 6000 psig,piston type main valve.CompatibilityElastomers, plastic seat, seals.Available for NACE service33

Features/Benefits341.Price: less expensive in larger valves2Size: 8″ x 10″ POPRV 32″ to 36″ tallSpring Loaded PRV is 60” tall3.Can be used dirty or wet service4.Balanced for back pressure5.Bubble tight up to 95% of set pressure

Features/Benefits6. Easy adjustment of set pressure and blowdown (reseat)adjustment7. Reduced maintenance costs, no lapping or machiningof parts (pilot can be replaced as a part)8. Remote pressure pickup9. Manual or remote blowdown10. Field test connection11. Pilot lift lever available35

POPRVOptions36

Field Test Connection(Series 200 POSV)37

Field Test Procedure(Series 200)Block Valve "B"Flexible HoseField TestConnectionTest GaugeVent Valve "C"Block Valve"A"N2Gas Bottle38

Field Test Connection and Indicator(Series 400 POSV)Pilot BodyPlunger SealSystemPressurePlunger SeatShuttle Seats39

Field Test Procedure(Series 400 POSRV)Field Test ConnectionGas VentFlexible HoseTest GaugeBlock Valve "A"N2Vent Valve "C"40Gas Bottle

Back Pressure on POPRVP1APASPistonP2P2P141P2

Series 200 POPRVwith Backflow PreventerPilotBackflowPreventerP2 P1P2Process PressureP142Discharge Pressure

Backflow Preventer(Can Be Field Retrofitted)43

For Dirty ServiceAuxiliary FilterIn Pilot Supply44

Pilot Supply FilterIn (From Pilot Tube OrRemote Sense)Out(To Pilot Inlet)45Element(11 in2) [71 cm2]316 S.S.53 Micron

Remote Pressure Sensing Option for Dirty Serviceand/or Excessive Inlet otePressureSensing

Iso-Dome Series 400 POSRVSet PressureAdjustmentSenseDiaphragmClean GasSupply Process47Regulator(Supplied by AG/C,Set, Sealed andMounted on PRV)Clean GasBy Customer

Pressure Spike Snubberfor Gas Service48

Positive Displacement Compressor(PRV Relieves ngPressure Pulsationsthat the PRV Reacts toTime

AG/C POPRVwith Pressure Spike SnubberPressureSetPressure at Pilot InletPressure at Main Valve SeatTimePressure SpikeSnubber50

Pressure Spike SnubberOutlet toSeries 200,400, or 800 PilotMaximum Pressure3705 psig [255.5 barg]143 Micron, 316 S.S.FilterInlet51

Packed Lift LeverREF:UG136 (A) (3)52

Manual Blowdown Valve53

Remote UnloaderRemotelyActuatedPneumaticorSolenoid Valve(NC or NO)Main Valve54

Low PressureVariations:Series 90 Pilot55

Low PressureVariations:Series 9356

Code Updatefor 21 addenda Being added - UG-129(a)(9)The pilot and main valve of a pilot operatedpressure relief valve shall each be marked withthe same unique identifier to establishassociation of both components. Work on remote mounted pilots is ongoing57

Thanks – questions?Pictures courtesy of:Anderson GreenwoodConsolidated Valve58

Pressure Relief Valves (POPRV) . Mercer. Taylor Valve. Leser. Apparecchi. Weir Power. Early Pilot Valve Usage 5. 6 Basic Operation. The Pilot controls the Main Valve action of: - Opening Pressure - Closing Pressure - Style Of Action Pilot. Main Valve. 7. Below set pressure, force imbalance due to differential area keeps main valve closed. Dome. Piston. Seat. Piston Seal. Basic Operation. 8 .