Pressure-relief Valves

Pressure-relief valves are found in virtually every hydraulic system, and they assist in a variety of functions, from keeping system pressures safely below a desired upper limit to maintaining a set pressure in part of a circuit. Types include relief, reducing, sequence, counterbalance, and unloading. All of these are normally closed valves, except for reducing valves, which are normally open. For most of these valves, a restriction is necessary to produce the required pressure control. One exception is the externally piloted unloading valve, which depends on an external signal for its actuation.
Types of pressure relief valves :
1. sub plate -pressure relief valve - up to 400 bar pressure
2. Line mounted -pressure relief valve - up to 400 bar pressure
3. Catriage -pressure relief valve - up to 600 bar pressure
4. PCM - pressure control model.
5. Pressure reducing valve .