Multistage compression type rotary compressor

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 side and a high pressure chamber side, 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, a 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 discharge muffling chamber of the first rotary compression element to a suction step region of the first rotary compression element or a region before reaching a discharge pressure of the first rotary compression element;
• a valve device having one surface to which a pressure in the discharge muffling chamber of the first rotary compression element is applied and having the other surface to which a pressure in a discharge muffling chamber of the second rotary compression element is applied to open or close the communication path;
• and
• a communication hole communicating the other surface with the discharge muffling chamber of the second rotary compression element to provide the pressure to the other surface;
• wherein
• the valve device is configured to open the communication path in a case where the pressure applied from the discharge muffling chamber of the first rotary compression element to the one surface reaches a predetermined upper limit value.