Patent ID: 7442017

Claim:
A displacement type compressor, comprising: a self-start synchronous motor which starts as an induction-motor, and performs synchronous operation by performing synchronous pull-in approximately at a synchronous rotational frequency; a compression part which comprises a compression chamber for compressing a working fluid; a hermetic container which houses the self-start synchronous motor and the compression part; and a start load reducing means for reducing a load of the compression part at startup, which means is placed at the compression part and located in the hermetic container, wherein the displacement type compressor is a scroll compressor, and wherein the compression part is constructed to include a rotary scroll which has an end elate and a spiral shaped scroll lap vertically provided on the end plate, and rotationally moves in an plane orthogonal to an axial direction corresponding to a direction in which the scroll lap is vertically provided, without performing autorotation, a fixed scroll which has an end plate and a spiral scroll lap vertically provided on the end plate, and is generally restricted in movement at least in an in-plane direction orthogonal to an axial direction corresponding to a direction in which the scroll lap is vertically provided, and a compression chamber constructed between both the scrolls by meshing the rotary scroll and the fixed scroll, and the start load reducing means is constructed to include a communication passage which is formed in the fixed scroll to allow the intermediate portion of the compression chamber and a discharge space formed in the hermetic container to communicate with each other, and a check-valve which is provided at the fixed scroll to prevent the working fluid from flowing into the compression chamber from the discharge space through the communication passage.