A pilot operated safety relief valve uses a small pilot valve to sense line pressure and control a larger main valve piston, keeping the main valve held tightly shut using process pressure itself until the set point is reached. Because the main valve seals using process pressure rather than a mechanical spring alone, this design achieves tighter shutoff at pressures very close to the set point, reducing the simmer and leakage that can occur with a conventional spring loaded relief valve. This makes pilot operated valves well suited to applications where operating pressure runs close to the relief set point and any premature leakage would waste product or trigger unnecessary venting.

Common Applications

• Applications where operating pressure runs close to the set point
• Large diameter relief service requiring tight shutoff
• Storage tank and vessel overpressure protection
• Systems requiring modulating action to minimize product loss