BIRKETT WB SERIES SAFETY RELIEF VALVES
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EMERSON.BIRKETT WB SERIES SAFETY RELIEF VALVESSpring loaded safety relief valves with a fuff lift and fuff nozzle to relieve excess pressure safefy in a variety of process vesselsFEATURES GENERAL APPLICATION The WB series is designed to refieve excess pressure safefy in pumps, pipe work, tanks, caforifiers, gas and oif separators and other process vessefs. Modefs are avaifabfe for gas, steam, vapor and fiquid appfications. TECHNICAL DATA Materiafs: Carbon steef, stainfess steef DN 2001 Connections Ffanged ANSI 150# to Pressure: Up to 6000 psig (414 barg) • Fuff nozzfe, fuff fift provides high discharge coefficients and high capacities. • Broad sefection of vafve types: conventionaf or beffows for gas or fiquid service enabfes optimum vafve sefection. • Wide range of materiafs provides sofutions for any appfication. • Lightweight construction reduces handfing and shipping costs and benefits offshore service. • Seat feakage integrity minimizes fugitive emissions. • Interchangeabfe parts enabfe simpfe modification from gas to fiquid and conventionaf to beffows. • In-situ testing capabifity reduces maintenance costs. • Reduced number of parts minimizes inventory and reduces maintenance costs. • Vafves conform to API 526 pressure/ temperature ranges, orifice areas and dimensions. • Extensive accessory range enabfes vafves to be adapted to meet specific code and appfication requirements. • Optionaf cfeaning for cryogenic and oxygen services avaifabfe. Emerson.com/FinalControl © 2017 Emerson. Aff Rights Reserved VCTDS-03791-EN 18/01

BIRKETT WB SERIES SAFETY RELIEF VALVES OVERVIEW MODEL OPTIONS The WB Series is available in four different valve types to suit differing service requirements: WB400 - conventional gas type. WB300 - bellows gas type. WB200 - conventional liquid type. WB100 - bellows liquid type. CONVENTIONAL SAFETY RELIEF VALVES These valves can be used on systems where the discharge is relatively simple. The pressure in the discharge system can be atmospheric, at a constant level or where it may build up to a maximum of 10% of the set pressure. When a constant back pressure exists, the valve should be set...

BIRKETT WB SERIES SAFETY RELIEF VALVES FEATURES 3. High performance springs 4. Bellows back up piston (not shown) 5. Guiding 6. Bellows (not shown) 7. Trim 8. Seat integrity 9. Adjustable blow down 10. Nozzle design 11. API 526 face to face dimensions Valves can be supplied suitable for application of ‘in-situ’ set pressure verification devices. Wide accessories range to comply with international codes and suit system requirements. High performance springs designed specifically to guarantee set point repeatability. Optional auxiliary back-up piston for balanced bellows valves ensures...

BIRKETT WB SERIES SAFETY RELIEF VALVES OPERATION PRINCIPLE OF OPERATION Spring force Safety relief valves use a spring force to hold a disc against a nozzle. Under normal system operating pressure, the valve will remain closed as the spring force is greater than the inlet system pressure force. The valve opens when the system pressure force becomes greater than the closing force of the spring. The WB Series are designed to have a short simmer, open rapidly to full lift position and then re-seat at a controlled shut off pressure. This is demonstrated in the graph below, which shows the valve...

BIRKETT WB SERIES SAFETY RELIEF VALVES OPERATION LIFT CYCLE Stage 1 - Closed Inlet pressure < set pressure Huddling chamber Inlet pressure is below the set pressure. The valve is closed and there is no flow through the valve. Reaction hood Exit area Blowdown ring Stage 2 - Simmering Inlet pressure is = > set pressure and < popping pressure Inlet pressure increases to set pressure. At this point, the spring force and system pressure force are equal; a further rise in inlet pressure will then begin to lift the disc slightly. A small amount of fluid is released into the huddling chamber (the...

BIRKETT WB SERIES SAFETY RELIEF VALVES OPERATION THE EFFECT OF BACK PRESSURE The configuration of a closed discharge pipework system, typically for toxic or hazardous duty, can generate back pressure. When applied to the valve outlet, this will affect its performance adversely, unless it is addressed. Back pressure can take three forms: 1. Superimposed constant back pressure This exists permanently and a conventional or bellows valve can be used. A conventional valve can be set at the differential pressure so that the spring load is adjusted to take account of the back pressure. 2. Built up...

BIRKETT WB SERIES SAFETY RELIEF VALVES MATERIALS OF CONSTRUCTION WB 400 - CONVENTIONAL GAS TYPE (up to and including class 600) Part Body Casing Cap Nozzle Disc Disc holder Blowdown ring Guide assy Spindle Lower spring plate Adjusting screw Locking nut Setting screw Setting screw rod Stud Nut Spring Body gasket Cap gasket Set screw gasket Ball Upper spring plate Data plate Hammer drive screw Grooved pin Drain plug Circlip Carbon steel SA 216-WCB CARB ST SA 216-WCB CARB ST SA 216-WCB CARB ST 316 ST ST 316 ST ST ASTM A479-316L SA 351-CF8M ST ST CARBON ST/17-4 ST ST ASTM A479-431 ASTM...

PARTS LIST Item Part 11 Lower spring plate 32 Upper spring plate 34 Hammer drive screw Carbon steel SA 216-WCB CARB ST SA 216-WCB CARB ST SA 216-WCB CARB ST 316 ST ST 316 ST ST Included in item 23 SA 351-CF8M ST ST CARBON ST/17-4 ST ST ASTM A479-431 ASTM A108-1021/Ni PLT ASTM A479-410 ASTM A108-1021 ASTM A479-431 ASTM A479-316L SA 193-B7 CR/MOL ST SA 194-2H CARB ST Carbon steel ASTM A479-316L/SA240-316L ST-706 ST-706 ST-706 AISI 440C ST ST ASTM A108-1021/NI PLT 321 ST ST Electro brassed ST ASTM A479-431 HTS holo-krome ASTM A313-316 Stainless steel SA 351-CF8M ST ST SA 351-CF8M ST ST SA...

BIRKETT WB SERIES SAFETY RELIEF VALVES MATERIALS OF CONSTRUCTION WB 400 - CONVENTIONAL GAS TYPES (class 900 and above) Part Body Casing Cap Nozzle Disc Disc holder Reaction hood Blowdown ring Guide plate Spindle Lower spring cap Adjusting screw Locking nut Setting screw Setting screw rod Tabwasher Pinning screw Body stud Body nut Casing stud Casing nut Spring Spindle head Body gasket Cap gasket Setting screw gasket Ball Upper spring cap Data plate Hammer drive screw Grooved pin Drain plug Carbon steel SA 216-WCB CARB ST SA 216-WCB CARB ST SA 216-WCB CARB ST 316 ST ST 316 ST ST ASTM...