Multi-stage rotary compressor

摘要

A multi-stage compression type rotary compressor (10) characterized in that the rotary compressor (10) comprises:
a sealed vessel (12);
an electrical-power element (14) having a rotary shaft (16);
a first rotary compression element (32) and a second rotary compression element (34) driven by the rotary shaft (16) of the electrical-power element (14), wherein the electrical-power element (14) and the first and second rotary compression elements (32,34) are arranged in the sealed vessel (12), and a refrigerant compressed by the first rotary compression element (32) is compressed by the second rotary compression element (34), and the refrigerant comprises a combustible refrigerant, and the refrigerant compressed by the first rotary compression element (32) is discharged to the sealed vessel (12), and the discharged refrigerant is under a medium pressure and is further compressed by the second rotary compression element (34); and
a pressure equalizing valve (40) for communicating with the discharge side of the refrigerant in the second rotary compression element (34) and the sealed vessel (12) when a pressure at a discharge side of the refrigerant in the second rotary compression element (34) is lower than a pressure in the sealed vessel (12).