Short reverse rotation of compressor at startup

#This invention relates to a unique method of minimizing the detrimental effect of scroll or screw compressors flooded starts.

#Scroll compressors are widely utilized in refrigerant compressor operation. One known type of scroll compressor includes compression elements and an electric motor housed within a sealed compressor shell. A quantity of lubricant is also received in the compressor shell. In such compressors, the refrigerant passes over the motor on its way to the inlet of the compression elements, cooling the motor.

#In a scroll compressor a pair of scroll members have wraps which interfit with each other to define compression chambers. When rotated in a forward direction, a normal compression process occurs in which refrigerant is trapped between the wraps and compressed towards a discharge port.

#FIG. 1 is a view of the scroll compressor incorporated into the present invention.

#FIG. 2 is a schematic view of a refrigerated container.

#FIG. 3 is a view of a screw compressor.

#FIG. 1 shows a compressor 20 for practicing the present invention. As shown, a sealed compressor shell 21 receives a compressor pump unit 22 consisting of fixed scroll 39, orbiting scroll 33, and crankcase 5. An outlet 26 is formed at a location sealed from the inlet 24. A motor 28 is positioned in the sealed compressor shell 21, and has its rotor 29 spaced from its stator 30. The motor drives a shaft 32 which in turn drives the orbiting scroll 33 of a scroll compressor.

#As shown, oil 34 fills the oil sump 35 and the bottom of rotor 29 and shaft 32 rotate within the oil sump. As known, oil travels up a passage 37 within the shaft 32 to lubricate bearings, and fixed 39 and orbiting scroll 33. The fixed scroll is supported by crankcase 43 and the shaft is supported axially by lower bearing ring 45.

#During normal operation, the rotor and shaft rotate in a forward direction and the scroll compressor compresses fluid. Fluid enters the compressor shell 21 through inlet 24 and part of the fluid passes over the motor preheating the gas leading into the inlet of the compressor. Another portion of the fluid is delivered directly to the compressor pump 22. The compressor as described until now is as known in the prior art.