Patent attributes
A screw compressor includes a screw rotor, a casing and an economizer circuit. The screw rotor has a plurality of helical grooves forming a compression chamber. The casing has a cylinder portion with the screw rotor inserted in the cylinder portion. The economizer circuit ejects configured to eject intermediate pressure refrigerant into a compression chamber in the course of compression. The economizer circuit includes a branch passage configured to branch the intermediate pressure refrigerant from a portion of a refrigerant circuit, a resonance space connected to a downstream side of the branch passage to retain the intermediate pressure refrigerant, and a resonance passage having an end communicating with an interior of the compression chamber and an other end communicating with an interior of the resonance space. The refrigerant circuit circulates refrigerant and performs a refrigeration cycle.