Patent ID: 7753665
Filing Date: 2010-07-13
Classification: F04C

Abstract:
1. Screw compressor for extremely high discharge pressures, for application in refrigeration systems operating on CO 2 in a transcritical process, featuring two rotors forming a rotor pair, a male rotor and a female rotor having a ratio of male-to-female rotor lobes of 4:6, 5:6 or 5:7, with the male rotor having a driving-shaft, and both rotors being enclosed in a housing featuring an inlet port for passing of the working fluid into cavities of the rotor pair and an outlet port for discharge of the gas out of the cavities of the rotor pair due to rotation of the rotors, with profile sections of the rotors having shaft shoulders enclosed in radial bearings, and the resulting axial forces being supported by axial bearings, wherein the wrap angle of the profile section of the male rotor is less than 1.5 times the lobe-pitch angle of the male rotor, and the working cycle from the beginning of suction till the end of discharge is less than 600° of the angle of rotation of the male rotor.