Patent ID: 6328546
Filing Date: 2001-12-11
Classification: F04C

Abstract:
A screw compressor for compressing working fluids by engaging a male rotor and a female rotor within a casing, wherein the screw compressor is an oil injecting type screw compressor in which a flow rate reducing section is provided by eliminating a part of a rotor engagement of one of the rotors from an intake side end towards a direction of a shaft; the one of the rotors is the male rotor of which a peripheral portion of each tooth radially outward from a pitch circle near the tooth base is eliminated to an axial distance corresponding to an angle of rotation .alpha..degree. from the intake side end in correspondence with a capacity amount to be reduced to form the flow rate reducing section in stepped shape leaving the rotor part including the pitch circle near the tooth base not eliminated; and a substantially annular space between the rotor part including the pitch circle and an inner circumferential face of the casing is composed as a bypass passage to the intake port.