WCB Pressure Safety Valves , Pilot Operated Safety Valve For Air Pipeline
Quick Detail:
- Pressure Rating: Inlet Class 150~2500, Outlet Class 150 - 300
- Base Material: ASTM A216 WCB, ASTM A351-CF8, SPECIAL STEEL
Performance
- The allowable tolerance of the set pressure:≤±3% of the set pressure
- Overpressure: ≤±10% of the set pressure
- Blowdown: ≤±10% of the set pressure
- Tightness: The valves have good seat tightness, conforms to API Std 527
Features
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The soft design provides good seat tightness before and after each relief cycle.
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The system can be operated nearer set pressure without valve leakage.
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No more overpressure required for full lift of main valve.
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Proper valve operation and lift are unaffected by back pressure.
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Adjustable blowdown.
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Non-flowing pilot reduces product loss and environmental pollution.
- Quick simple verification of set pressure while valve remains in service.
Principles of operation
In the normal closed position, system pressure is transmitted through the pilot valve and into the dome
of main valve. The pressure above the main valve disc generates a net downward force, hold the main
valve closed.
When system pressure reaches the set pressure, the pilot spindle lifts and reseat piston closed
simultaneously, venting the dome pressre through the pilot valve to atmosphere. Because of system
pressure remains above reseat pressure, the reseat piston is held tightly closed, blocking flow to the
pilot valve (the non-flowing pilot valve feature), at this time the dome pressure of main valve is
depressed quickly, allowing the main valve to open fully.
When the desired system pressure is achieved, the pilot spring force overcomes force on the reseat
piston, the reseat piston snaps open and the pilot spindle snaps closed simultaneously. Finally,
system fliud reenter the dome and closes the main valve.