The main function of pressure reducing valve is to reduce the pressure in particular branch of the circuit to different level as demanded by consumer in that branch.

Construction:

It consists of spool and spring housed in the bore of valve body. Spring compression can be adjusted by pressure setting screw. Port P is pressure port connected to pump. Port A is consumer port requiring reduced pressure.

Working:

As shown in normal position, port P is supplying oil to consumer port A. If the main supply is below the set pressure, there will be continuous flow from P to A. Hence normally this valve is open.

When outlet pressure rises to valve setting then oil will flow through ‘passage x’ and will act on spool and spool will shift to right thereby partly closing the port A. Now only enough flow will pass through port ‘A’ so that consumer connected to A will receive reduced pressure.