The subject invention pertains to a method and apparatus for an orientation independent compressor. The subject compressor can be part of a vapor compression cycle system, and can use one or more of a variety of working fluids, including, but not limited to, refrigerants such as r-134a, r-22, CO.sub.2, and NH.sub.3. Embodiments of the compressor can utilize positive displacement apparatus to compress the vapor. In a specific embodiment, the compressor can incorporate an oil-lubricated rotary lobed type positive displacement compressor. In a further specific embodiment, the working fluid vapor can be a refrigerant, such as r-134a, incorporating entrained oil, such as miscible lubricating oils. An example of such a miscible lubricating oil that can be used is polyester (POE) oil.

A motor operated compressor includes an orbiting scroll that defines a compression chamber together with a fixed scroll. The compressor includes a main frame disposed around and supporting the orbiting scroll. The main frame defines a back-pressure chamber together with the orbiting scroll. The compressor includes a groove disposed in one of the orbiting scroll and the main frame. A first sealing member is inserted into the groove. A second sealing member is inserted into the groove to elastically press the first sealing member into close contact with the orbiting scroll or the main frame. A radial distance (a) between an outer wall of the groove and the first sealing member is 6 to 8% (0.06a/W0.08) of a difference (W) between an outer radius (OR) and an inner radius (IR) of the first sealing member (W=ORIR).