US 3618337 A
Description (OCR text may contain errors)
NOV. 9, 1971 MQUNT 3,618,337
HERMETIC REFRIGERATION COMPRESSOR Filed June 22, 1970 INVENTOR. GORDON L MOUNT ATTOENEY Patented Nov. 9, 1971 3,618,337 HERMETIC REFRIGERATION COMPRESSOR Gordon L. Mount, West Monroe, N.Y., assignor to Carrier Corporation, Syracuse, N.Y. Filed June 22, 1970, Ser. No. 48,360 Int. Cl. F2511 31/00 US. Cl. 62505 5 Claims ABSTRACT OF THE DISCLOSURE The lower end of the casing of the vertically mounted hermetic compressor unit is formed with an oil sump to which liquid refrigerant is supplied. The liquid oil-refrigerant mixture is elevated from the sump by a lift tube fixed to and depending from the motor rotor. During operation of the motor, a rotational vortex is formed in the tube and the liquid mixture is passed upwardly through axially extending passages in the rotor and is dispensed on the upper and lower end turns of the stator windings. Suction is applied to the casing above the motor for removal of refrigerant vapor.
BACKGROUND OF THE INVENTION Many arrangements have been employed to cool electric motors by the use of a refrigerant. In some instances, the motor casing has been supplied with refrigerant vapor. In other arrangements, liquid refrigerant is directed on the motor components. The liquid refrigerant is capable of removing a great deal more heat from the motor than the refrigerant vapor. The arrangements employing the liquid refrigerant are costly, especially in that it is necessary to employ a power driven pump means for directing the liquid refrigerant on the motor parts. Also, in such arrangements, there may arise the possibility that the liquid refrigerant, or adequate supply thereof, may not be available on the start-up of the compressor.
My invention embodies a structural arrangement particularly economical to build and assemble, having only one part which is fixedly secured to the motor, the arrangement providing for a supply of liquid refrigerant available immediately on startup of the compressor and not dependent on condensation in the high side of the refrigeration cycle.
SUMMARY OF THE INVENTION In the arrangement embodying my invention, the casing of the vertical hermetic refrigeration compressor is formed in the bottom portion thereof with an oil sump to which liquid refrigerant is also supplied. The mixture of oil and refrigerant is passed upwardly from the sump through the motor rotor by a rotating lift tube fixed to the lower end of the rotor and depending into the liquid in the sump. As the refrigerant is flashed from the mixture, contacting the motor components, the same are effectively cooled. The casing above the sump area is connected to the low side of the refrigeration system, whereby the refrigerant vapor flashed from the mixture is removed from the compressor casing; and in that manner, the oil is separated from the refrigerant.
BRIEF DESCRIPTION OF THE DRAWING The drawing is a vertical sectional view of that portion of the casing of a hermetic compressor unit containing the compressor drive motor, and illustrating an embodiment of my invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, designates the side wall of a cylindrical casing to the lower end of which a closure 11 is secured as by screws 12. A compressor housing 13 is attached to the upper end of the casing wall 10 as by screws 15.
The casing wall 10 is formed with a plurality of circumferentially spaced internal ribs 16 which are machined to receive the motor stator 17 press fit fashion. The stator 17 is provided with windings having end turns 20 extending upwardly from the upper end of the stator, and like end turns 21 extending downwardly from the lower end of the stator.
A rotor 23 is fixed to a shaft 24 journaled in bearings 25 contained in the lower end of the compressor housing 13. The rotor 23 is accordingly journaled for vertical rotation within the stator 17. The rotor is formed or provided at its lower end with a chamber 25 from which a lift tube 27 depends.
The lower end of the motor casing serves as an oil sump containing a quantity of oil for the lubrication of the compressor unit. Means is provided for also supplying liquid refrigerant to the sump portion of the casing. As shown in the drawing, the supply of refrigerant may be obtained from the evaporator 30 of the refrigeration system, the liquid refrigerant being conducted through conduit 31 to the sump. A float-type metering valve maybe employed to maintain the oil-refrigerant liquid mixture at a predetermined level as indicated at the dashed line 33. The level control mechanism includes a valve 35 fixed to one leg of an angle lever 37, which is pivoted at its bight in a bracket 38 fixed to the inner surface of the motor casing, the opposite leg of the valve mechanism being provided with a float 40. In place of the valve structure described, the level of the refrigerant-oil mixture may be determined by the level of the refrigerant in the evaporator.
As shown in the drawing, the lower end of the lift tube 27 is immersed in the oil-refrigerant liquid mixture, the lower end of the tube being provided with an inlet orifice 41 dimensioned to provide the desired flow of the mixture. The orifice 41 is smaller than the cross-sectional area of the tube 27.
Upon rapid rotation of the rotor 23, and accordingly the tube 27, a rotational vortex is formed inside the tube 27 effecting elevation of the liquid upwardly into the chamber 25. The side wall of the chamber is provided with one or more passages 43 for the radial dispersion of the liquid on the lower end turns 21 of the stator windin s.
The rotor 23 is formed with a plurality of axially extending passages 45. The lower ends of these passages communicate with the chamber 25. The upper ends of the passages 45 open through the upper end of the rotor.
The diameter of chamber 25 is greater than the diameter of the tube 27. Due to centrifugal action, there is an annular accumulaton of liquid mixture against the side wall of the chamber. Preferably, the side wall of the chamber 2 5 is formed by the end ring 50 connected to the conductor bars 51 of the rotor squirrel cage winding. The pressurized liquid mixture is discharged through the passages 43 and dispersed on the lower end turns 21, of the stator windings as previously stated. Also, the pres surized mixture is elevated upwardly through the passages 45 and is dispersed outwardly over the upper end ring 55 onto the upper end turns 20' of the stator windings.
A conduit 60 extends to the low pressure side of the refrigeration system. As the oil-refrigerant mixture is passed in contact with the motor components, the refrigerant is flashed from the mixture, abstracting large quantities of heat from the motor.
The bearings 25 and other components of the compressor may be supplied with lubrication by a pump 61 having an inlet 62 in communication with the liquid mixture in the sump and having a discharge line 63 extending to the bearings and other components of the compressor needing lubrication. In the drawing, a branch line 65 provides a flow of the liquid mixture to the bearings 25. Excess of the liquid mixture from the bearings together with the oil separated from the mixture in the area of the motor is drained downwardly into the sump. The rotor may be formed with passages 70 extending radially outwardly from the passages 45 for dispersion of the liquid mixture in the air gap between the rotor and the stator to effect further heat extraction from the motor components.
The lift tube 27 may be provided intermediate its ends with a short radially disposed vent tube 71, the inner end of the tube extending inwardly from the side wall of the lift tube and terminating in the vortex indicated at 73. This vent tube serves to relieve any pressure that may develop in the chamber 25 and the passage 45 as a result of the flashing of the refrigerant from the mixture in those areas.
1. A hermetic refrigeration compressor unit comprising a closed casing formed at the bottom area thereof with a sump containing a liquid mixture of oil and refrigerant, a compressor drive motor vertically mounted in said casing in upwardly spaced relation from said sump for driving a compressor mounted above said motor, means for supplying liquid refrigerant to said sump, means connected to said casing for withdrawing refrigerant vapor from said casing, said motor including a fixed stator with operating windings having exposed end turns at the upper and lower ends of said stator, a rotor journaled for rotation within said stator about a vertical axis, said rotor being provided at the lower end thereof with a chamber having a coaxial depending tubular portion, the lower end of said tubular portion being immersed in said oil-refrigerant liquid in said sump, said rotor being formed with a plurality of axially extending passages communicating at their lower ends with said chamber, the upper ends of said passages opening through the upper end of said rotor, said tubular portion being operable upon rotation of said rotor to elevate said liquid mixture from said sump upwardly through said chamber and said passages for radial dispersion of said liquid mixture on the upper end turns of said stator windings, the side wall of said chamber being formed with an aperture for the radial dispersion of said liquid mixture against the end turns of said windings at the lower end of said stator.
2. A hermetic refrigeration compressor unit as set forth in claim 1 and including level control means operable to maintain the oil-refrigerant mixture at a predetermined level in said sump.
3. A hermetic rferigeration compressor unit as set forth in claim 1 wherein said motor rotor is provided with a squirrel cage Winding, the end ring of said winding at the lower end of said rotor forming the side wall of said chamber.
'4. A hermetic refrigeration compressor unit as set forth in claim 1 wherein said chamber is of circular form and is arranged concentric with the axis of said rotor.
5. A hermetic refrigeration compressor unit as set forth in claim 1 wherein said rotor is formed with branch passages extending radially outward from said axially extending passages for discharge of said liquid mixture in the air gap of said motor.
References Cited UNITED STATES PATENTS 1,967,033 7/1934 Lipman 62469 1,964,415 6/1934 Van Deventis 62-469 2,047,753 7/1936 Steining 62192 3,039,677 6/ 196 2 Nissley 6Z469 3,410,478 11/ 1968 Geisenhaver 417-366 WILLIAM J. WYE, Primary Examiner US. Cl. X.R.