Patent ID: 7232298

Claim:
A helical screw rotor compressor comprising: a rotor housing that includes a first end wall and a second end wall, wherein said walls are parallel with one another and connected by a barrel wall, wherein said barrel wall has internally the shape of two parallel and mutually intersecting cylinders, and wherein the rotor housing further includes an inlet port at a first end and an outlet port at a second end, two rotors which co-act with each other and also with the rotor housing and each of which includes a respective shaft mounted in end walls of the compressor housing, and a respective rotor body surrounding a respective shaft, said bodies having parallel end surfaces between the end walls of the rotor housing, wherein each said rotor body includes mutually separated helical lobes that have a crown, a first or leading flank surface on a first side of the crown and a second or trailing flank surface on a second side of the crown, and wherein the second or trailing flanks of said lobes of at least one of the rotor bodies are beveled or chamfered adjacent to an end surface of the rotor body at said outlet port.