Double Block & Bleed Valves Valve

The primary function of a double block and bleed valve is for isolation and the secondary function is for intervention (diverting / sampling / injection etc).

Double block and bleed valves operate on the principle that isolation can be achieved from both the upstream and downstream process flow / pressures. This is achieved by two ball, gate, globe, needle, etc. valves placed back to back, with a third “isolatable” valve in the centre cavity. Once isolation has been achieved in one or more of the main process isolation valves, the cavity that is created between these isolations can be drained. This is useful for flow diverting, sampling or injection situations, and for maintenance / integrity check situations where seat leakage can be monitored through the third “bleed” valve.
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Double Block & Bleed Valve Specification

Click for more Double Block & Bleed Valves - General Design Criteria  
  • Multiple Configurations with Ball, Gate, Globe, Needle Options
  • Full or Reduced Bore
  • Manual Lever, Gear or Actuator Operated
  • Special Seat Design Options - Self Relieving / Double Piston Effect
  • Operating temperature and fluids suitability - further information on request
  • Firesafe / Cryogenic / Gas Service certified options
  • Modification service available for all stock options
Click for more Standard Pressure Class Ratings / End Connections
  • ANSI 800, 1500 & 2500lb - Threaded, Socket Weld and Butt-Weld ends
  • ANSI 150, 300, 600, 800, 1500 & 2500lb - Flanged RF, RTJ, Butt-Weld and Hub ends
  • PN, API and other Pressure Class Valves available on request

Common Materials of Construction Material Specifications
Standard Carbon Steel ASTM A105
A216 WCB
WCC
Low temperature Carbon Steel ASTM LF2
A352 LCC
LCB
Stainless Steel ASTM A182 F316
ASTM A182 F316L
ASTM A182 F304
ASTM A182 F304L
ASTM A182 F321
ASTM A182 F347
ASTM A351 CF8M
ASTM A351 CF3M
Specials F44
SMO
F51
Duplex
Super Duplex
Monel
Hastelloy
Titanium
Inconel
Bronze
Alu. Bronze
Other Actuated
Double Block and Bleed Valve