Unique, modulating action pilot operated relief valve with soft seats having the ability to handle hot water, steam, hot hydrocarbon vapors or liquids, using inert plastic soft goods.

There are four types for PWR pressure-relieving devices: direct acting safety valve, pilot-operated pressure relief valve, power-operated pressure relief valve and safety valve with auxiliaries.

The experiments were carried out with different supply pressure, flow rate and the pilot-operated water hydraulic relief valve opening on.