Patent ID: 7621729

Claim:
A multistage compression type rotary compressor comprising, in a sealed vessel, a driving element; and first and second rotary compression elements driven by the driving element, the second rotary compression element comprising a cylinder; a roller fitted into an eccentric portion formed on a rotary shaft of the driving element to eccentrically rotate in the cylinder; and a vane which abuts on the roller to separate a low pressure chamber side and a high pressure chamber side from each other, the rotary compressor being configured to apply a pressure of the second rotary compression element on a refrigerant discharge side as a back pressure of the vane, suck, in the second rotary compression element, an intermediate pressure refrigerant gas compressed by the first rotary compression element and discharged, compress and discharge the refrigerant gas, the rotary compressor further comprising: a communication path which connects a region having an intermediate pressure to a region having a low pressure as a suction pressure of the first rotary compression element or a region before reaching the intermediate pressure; and a valve device which opens or closes the communication path, the valve device being configured to open the communication path in a case where a pressure difference between the pressure of the second rotary compression element on the refrigerant discharge side and the intermediate pressure reaches a predetermined value.