Patent ID: 8419397

Claim:
A screw compressor comprising: a casing having a cylinder; a cylindrical-shaped screw rotor configured to be fitted into the cylinder; and a gate rotor configured to be engaged with the screw rotor, with an outlet width of a seal surface of the casing on a gas-outlet side of the screw rotor being larger than an inlet width of the seal surface on a gas-inlet side of the screw rotor, the seal surface of the casing being opposed to one surface of the gate rotor, the seal surface having a first edge on a screw rotor side and a second edge opposed to the first edge, the first edge being formed so as to be parallel to an axis of the screw rotor, the second having a first portion and a second portion arranged in order from the gas inlet side toward the gas outlet side of the screw rotor, and the first portion being formed so as to be farther from the first edge on an outlet side thereof, and the second portion being formed on as to be parallel to the first edge.