Single machine screw multistage compressor and freezing and cooling system using the same

摘要

PPROBLEM TO BE SOLVED: To provide a screw compressor capable of striking a balance between high efficiency and long service life. PSOLUTION: In the single machine screw type multistage compressor 5 in which a high-stage compressor 3 and a low-stage compressor 7 comprising screw rotors and a drive motor 25 are integrally combined in series, the low-stage compressor 7 is provided with a low-stage economizer port 70 to which a low-stage economizer cooler is connected. The motor 25 is connected to a suction side of the low-stage compressor. A balance passage 80 introducing a pressure of an intermediate pressure chamber 63 connecting a discharge port 59 of the low-stage compressor and a suction port 65 of the high-stage compressor or a pressure of a compression stroke part of the high-stage compressor to a motor chamber 82 is provided. PCOPYRIGHT: (C)2012,JPO&INPIT