Patent ID: 8272846

Claim:
An apparatus for relieving pressure in a screw compressor, the screw compressor comprising a rotor case, the rotor case comprising a plurality of helical rotors, the plurality of helical rotors comprising a primary helical rotor and at least one secondary helical rotor, the primary helical rotor intermeshed with each of the at least one secondary helical rotor for compressing a refrigerant, the apparatus comprising: a slide valve supporting member fixed on an inner wall of the rotor case; a slide valve positioned between the plurality of helical rotors and the slide valve supporting member, the slide valve sliding axially on the slide valve supporting member, the slide valve controlling the volume of refrigerant to be compressed; and at least one internal pressure relief valve positioned to relieve said pressure from a discharge side of the compressor to a suction side of the compressor, each of the at least one internal pressure relief valve being fitted in the slide valve, each of the at least one internal pressure relief valve relieving pressure in the screw compressor, the pressure being relieved based on a pre-determined setting.