Rotary compressor, method for manufacturing the same, and defroster for refrigerant circuit

A multi-stage compression type rotary compressor comprising an electrical-power element and first and second rotary compression elements driven by the electrical-power element in a sealed vessel in such a configuration that a refrigerant gas compressed in the first rotary compression element and discharged therefrom is sucked into the second rotary compression element to be compressed and discharged therefrom, the multi-stage compression type rotary compressor further comprising:

• a communication path which communicates a refrigerant suction side and a refrigerant discharge side of the first rotary compression element to each other, and a valve device which opens and closes this communication path,
• wherein the valve device opens the communication path, if a pressure difference between the refrigerant suction side and the refrigerant discharge side of the first rotary compression element exceeds a first predetermined upper limit value;
• and further comprising a cylinder constituting the first rotary compression element,
• a support member which blocks an opening face of this cylinder and which has a bearing for the rotary shaft of the electrical-power element, and
• a suction path and a discharge-noise silencer chamber which are arranged in the support member,
• wherein the communication path is formed in the support member to communicate the suction path and the discharge-noise silencer chamber to each other, and the valve device is provided in the support member.