Patent ID: 7611342

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 divide the inside of the cylinder into a low pressure chamber and a high pressure chamber, 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 into the sealed vessel, compress and discharge the refrigerant gas, the rotary compressor further comprising: a communication path which connects a space in the sealed vessel to the first rotary compression element on a refrigerant suction side; and a valve device having one surface to which a pressure of the space in the sealed vessel is applied and having the other surface to which the back pressure of the vane is applied to open or close the communication path, the valve device being configured to open the communication path in a case where the pressure applied from the space in the sealed vessel to the one surface reaches a predetermined upper limit value.