Multistage rotary compressor and refrigeration circuit system

摘要

A multistage rotary compressor (10) comprising an electric element (14) in a hermetic shell case (12), and first and second rotary compression elements (32), (34) being driven by said electric element (14), wherein an intermediate pressure refrigerant which is compressed by said first rotary compression element (32) is drawn and compressed by said second rotary compression element (34) and discharged thereby, said multistage rotary compressor (10) comprising: a communication path (100) for communicating between a path through which the intermediate pressure refrigerant compressed by said first rotary compression element (32) flows and a refrigerant discharge side of said second rotary compression element (34), and a valve unit (101) for opening and closing said communication path, wherein said valve unit (101) opens said communication path 100 when a pressure of the intermediate pressure refrigerant becomes higher than a pressure at the refrigerant discharge side of the second compression element (34).