PILOT OPERATED SAFETY VALVE

Pilot Operated Safety Valve Descriptions

Pilot operated safety valve is one important protection unit in the pipeline. In the normal closed postion, 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 pressure through the pilot valve to atmosphere. Because of system pressure remains above reseat pressure, the reseat piston is hold 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 fluid reenter the dome and closes the main valve. We can manufacture the pilot operated safety valve in accordance with ISO4126, API RP520, JIS8210, DIN3320. 

1. FEATURES 

• The soft seat design makes sure the safety valve have good sealing performance before or after relief.

• Allowing the working pressure nearer the set pressure without leakage.

• When there is little overpressure, the safety valve can achieve in full open quickly.

• The safety valve action performance and open do not be affected by back pressure.

• Adjustable blowdown.

• Non-flowing pilot valve construction design reduces the harmful medium discharge and environmental pollution.

2. TECHNICAL SPECIFICATIONS 

• Class rating: 150LB~2500LB

• Size: 1″-10″ (DN25~250mm)

• Materials: steel A216 WCB, stainless steel 304 (A351 CF8), stainless steel 316 (A315 CF8M), CF3M, Monel, Hast. C

• Set pressure tolerance: ≤±3%

• Overpressure: ≤10%

• Blowdown: ≤10%

3. STANDARDS 

• Design & manufacturing: ISO4126, API RP520, JIS8210, DIN3320

• Flanged ends: ANSI B16.5a, JIS B2212-2216, DIN2546-2551

• Face to face: API 526, JIS B2001, DIN3202

• Inspection & testing: API 527

4. APPLICATIONS 

• Applicable medium: steam, air, gas, LPG, oil, corrosive liquids

• Applicable temperature: -29℃~+350℃

• Applicable fields: boiler, oil & gas field, steam equipment, oil vessel, pressure vessel