SCREW TYPE MULTISTAGE COMPRESSOR SWITCHABLE TO MULTISTAGE COMPRESSION AND SINGLE STAGE COMPRESSION AND REFRIGERATING AND COOLING SYSTEM USING IT

摘要

PROBLEM TO BE SOLVED: To provide a screw type multistage compressor and a refrigerating and cooling system using it whereby the multistage compressor can be switched to function as an original multistage compressor and function as a single stage compressor for respective compression stages independently, to generate an extremely low temperature in the daytime and to supply cold heat at night.;SOLUTION: In this screw type multistage compressor, a delivery port of a low pressure stage and a suction port of a high pressure stage are connected to each other at a connection passage through a selector valve, and a check valve is provided on an upstream side of a suction passage branching at a connection part. The multistage compressor can be switched by switch of the selector valve to function as the two stage compressor and as the single stage compressor for the respective compression stages independently. In the daytime, multistage compression operation is performed with the usage of the multistage compressor in order to cope with the load of a freezer requiring the extremely low temperature. At night, the operation is switched to the operation wherein the respective compression stages are functioned as the single stage compressor in order to store the cold heat. The cold heat is used for air-conditioning of a factory or for as cold water production processes.;COPYRIGHT: (C)2004,JPO