Difference between Pressure Safety Valve and Pressure Relief Valve.

Difference between Pressure Safety Valve and Pressure Relief Valve:

Although freely used interchangeably, these terms differ in the following aspect,

## Pressure Relief Valve - is the term used to describe relief device on a liquid-filled vessel. For such a valve the opening is proportional to the increase in the vessel pressure. Hence the opening of the valve is not sudden, but gradual if the pressure is increased gradually.

##Pressure Safety Valve - is the term used to describe the relief device on a compressible fluid or gas-filled vessel. For such a valve the opening is sudden. When the set pressure of the valve is reached, the valve opens almost fully.