Intermediate pressure regulating valve for a scroll machine

Abstract

A valve for regulating pressure intermediate suction and discharge pressure in a scroll compressor having an axially sealing interface between a fixed and orbiting scroll member through which the axial relationship between the scroll members may be controlled. The scroll members are axially biased together by refrigerant gas at a pressure intermediate the suction and discharge pressures and which is disposed in an intermediate pressure chamber defined in part by a generally planar surface of the orbiting scroll member. A self-regulating sliding valve, actuated by forces exerted on axial valve surfaces by suction, discharge and intermediate gas pressures, controls the amount of intermediate gas pressure in the intermediate gas pressure chamber. An annular groove in fluid communication with a longitudinal bore within the valve body and which opens to the intermediate pressure chamber is moved between a first position, in which the annular valve groove communicates with a passage to the compressor discharge pressure chamber, and a second position, in which the annular valve groove communicates with a passage to the compressor suction pressure chamber, placing the intermediate pressure chamber in communication with the discharge and suction pressure chambers, respectively. A third position, intermediate the first and second positions, seals the intermediate pressure chamber. Hence the axial engagement force exerted between the fixed and orbiting scroll members is controlled and a constant wrap to face clearance between the fixed and orbiting scroll members is maintained.