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Anderson Greenwood Series 200/400/500/700/800 Pilot Operated Relief Valves
Series 200/400/500/700/800 Pilot Operated Relief Valves
Premium performance and advanced technology for overpressure protection.
 Global leading technology in pilot operated pressure relief valves for city gate, district station and end of line overpressure protection.


  • Soft seat design: Provides repeatable bubble-tight performance before and after each relief cycle.
  • Metal-to-metal seat design: Provides pilot valve performance in high temperature service.
  • Bubble-tight seats near set pressure: Allows higher system operating pressure and, therefore, maximum process output; not as sensitive to vibrational and pulsating service; reduces product loss.
  • Pop action available: No main valve throttling, which helps prevent freeze-ups in cryogenic or refrigerant type services.
  • Modulating action available: Minimized product loss per relief situation; reduced environmental pollution; avoids oversizing consequences; not as sensitive to inlet pressure losses as pop action.
  • Field test connection: Quick, simple verification of set pressure while valve remains in service.
  • Balanced design: Lift unaffected by back pressure; no expensive and fragile bellows required to balance against high back pressure.
  • Full lift at set pressure: No overpressure required for full lift; allows D.O.T. installation to be set higher than Maximum Allowable Operating Pressure (MAOP) when pop action is used.
  • Replaceable soft seats and seals: All seats and seals are renewable easily and quickly; no expensive, time-consuming seat lapping required.
  • High Gain Modulating Action available on 400 Series pilots providing full main valve lift by 5% overpressure while minimizing product loss during relief events.
  • API 526 direct spring center-to-face dimensions available for Series 200, 400, 500 and 800 pilots eliminating the need for piping modifications during upgrades.


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