Gas injection system for screw compressor

摘要

A refrigerant gas injection system for a refrigeration cycle of the type having a screw compressor provided with a slide valve for controlling the compression capacity of the screw compressor, an economizer disposed in a passage for refrigerant liquid and adapted for subcooling the refrigerant liquid by the refrigerant of a reduced pressure, and a refrigerant gas injection line through which the refrigerant gas generated in the economizer is injected into the compression chamber of the screw compressor in its compression phase. The refrigerant gas injection system has a gas injection controller adapted to enable the injection of the refrigerant gas when the screw compressor is operating at full (100%) capacity or load level and to prevent the injection of the refrigerant gas when the screw compressor is operating in unloaded state.