Vertical axis hermetic helical screw rotary compressor with discharge gas oil mist eliminator and dual transfer tube manifold for supplying liquid refrigerant and refrigerant vapor to the compression area

In a vertical axis hermetic helical screw rotary compressor comprising:

• a closed vertical axis cylindrical outer enclosure,
• an inner cylindrical casing of a diameter less than that of said outer enclosure,
• means for coaxially fixedly mounting said inner cylindrical casing within said outer enclosure, said inner cylndrical casing including transverse wall means separating said inner cylindrical casing into upper and lower chambers,
• a pair of vertical axis, laterally intersecting bores formed within said inner casing,
• intermeshed helical screw rotors within respective bores and forming with the bores a compressor working chamber,
• an inlet tube opening to said casing bores and said compression chamber at the upper end of said intermeshed helical screw rotors for supplying low pressure working fluid to said compressor,
• an electrical drive motor, said motor including a stator and a rotor, said motor rotor being coaxially mounted to the upper end of one of said helical screw rotors and said stator concentrically surrounding said rotor and being fixedly mounted to said inner casing within said upper chamber,
• means defining a compressor discharge passage within said inner casing for directing high pressure discharge gas from said compressor working chamber upwardly,
• fluid passage means within said electric drive motor rotor,
• oil within said outer enclosure collecting by gravity within the bottom thereof which functions as an oil sump,
• means for supplying oil to the rotating parts of the compressor from said sump at the discharge pressure of the compressor and being entrained in the compressor discharge such that;
• oil separates from the working fluid by centrifugal force due to rotation of the drive motor rotor and falls by gravity back into the sump;
• a liquid refrigerant injection port formed within said inner cylindrical casing and opening to said compressor working chamber,
• a vapor injection port carried by said inner cylindrical casing and opening to said working chamber at a point displaced from the liquid refrigerant injection port,
• said working fluid comprising a refrigerant, and
• means for supplying liquid refrigerant at compressor discharge pressure to said liquid injection port, and for supplying refrigerant in vapor form at a pressure intermediate of the suction and discharge pressure of the compressor to said vapor injection port,
• and wherein said supply means comprise separate lines for said liquid refrigerant and said vapor at intermediate pressure and includes control valves exterior of the cylindrical outer enclosure within the lines and acting to close off selectively supply lines leading to said liquid refrigerant injection port and said vapor injection port,
• the improvement wherein;
• said supply means comprises a dual transfer tube manifold assembly projecting inwardly of the cylindrical outer enclosure and being sealably and fixedly mounted thereto and spanning across the space between the cylindrical outer enclosure and the inner cylindrical casing and being of heat conductive material and bearing elongated parallel passages for said liquid refrigerant and said intermediate pressure vapor and being in fluid communication at their inboard ends with said liquid refrigerant injection port and said vapor injection port, respectively,
• whereby, when the control valves of said supply means are closed, working fluid pulsing back and forth within one of said parallel passages may be cooled by continued flow of injection fluid within the other of said parallel passages to thereby prevent excessive heat build up within the supply means injection passages leading from the cylindrical outer enclosure,
• and wherein, irrespective of injection fluid flow through said passages, said dual transfer tube assembly is cooled by drops of oil separated from the working fluid above the level of said dual transfer tube assembly and falling by gravity towards the accumulated oil within the sump and impacting on said dual transfer tube assembly.