What is PSV and PRV?

PSV stands for Pressure Safety Valve, which is a safety device that automatically releases pressure from a system or vessel to prevent overpressure.
PRV stands for Pressure Relief Valve, which is also a safety device that automatically releases pressure from a system or vessel to prevent overpressure. The main difference between PSV and PRV is that PSV is typically used for gas systems, while PRV is used for liquid systems.

Pressure Safety Valve

A safety valve is used to protect the system against overpressure. Overpressure occurs when the pressure exceeds the Maximum Allowable Working Pressure (MWAP) or the pressure for which the system is designed. Safety valves can open very quickly compared to relief valves. A safety valve opens from a set pressure; the valve first opens a little, after which it opens fully so that the unwanted pressure is removed from the system as quickly as possible.

PSV are used to prevent pressure increases, leading to malfunctions, fire hazards, or explosions. Safety valves only have mechanical parts, so they are used when electronic or pneumatic safety devices fail. A safety valve is fully actuated by the system's media, keeping it working in a power failure.

• Spring-loaded (Conventional type)

The opening and closing of a safety valve are determined by the balance between the spring force and the input force.

• Balanced Bellows

The bellows ensure that the back pressure does not influence the operation of the valve.

• Pilot operated

With Pilot operated valve, the response pressure can be closer to the working pressure without leaks or unwanted openings.

Pressure Relief Valve

Pressure relief valves are essential components in keeping hydraulic and pneumatic systems below a set pressure.

PRVs are used to either reduce the downstream pressure to a constant level whenever it exceeds a threshold or maintain sustained pressures down- or upstream from the valve.

Pressure relief valve (PRV) or Pressure Release valve (PRV) or pressure safety valve (PSV):