US3781138A

US3781138A - Seal sleeve for oil separator

Info

Publication number: US3781138A
Application number: US00246768A
Authority: US
Inventors: F Bellmer
Original assignee: Fedders Corp
Current assignee: Fedders Corp
Priority date: 1972-04-24
Filing date: 1972-04-24
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25

Abstract

In a hermetically sealed motor-compressor unit, a gas discharge tube extends into said unit to a position between the windings of the motor rotor. A circular rotor plate is mounted to the end of the rotor and has an opening formed therein through which the discharge tube is disposed. A flanged sleeve is positioned around the discharge tube and is held in place on the tube by spring tension of the sleeve itself. A flange portion of the sleeve seals a gap between the rotor plate and the discharge tube to prevent the flow of refrigerant gas and oil therethrough. The rotor plate is positioned so as to separate entrained oil from the refrigerant gas and is utilized for motor cooling.

Description

United States Patent [1 1 Bellmer i 1 SEAL SLEEVE FOR OIL SEPARATOR [73] Assignee: Fedders Corporation, Edison, NJ.

[22] Filed: Apr. 24, 1972 [21] Appl. No.: 246,768

Primary Examiner-Carlton R. Croyle Assistant ExaminerRichard Sher Attorney-David S. Kane et al.

[5 7 ABSTRACT In a hermetically sealed motor-compressor unit, a gas discharge tube extends into said unit to a position between the windings of the motor rotor. A circular rotor plate is mounted to the end of the rotor and has an opening formed therein through which the discharge tube is disposed. A flanged sleeve is positioned around the discharge tube and is held in place on the tube by spring tension of the sleeve itself. A flange portion of the sleeve seals a gap between the rotor plate and the discharge tube to prevent the flow of refrigerant gas and oil therethrough. The rotor plate is positioned so as to separate entrained oil from the refrigerant gas and is utilized for motor cooling.

8 Claims, 4 Drawing Figures PATENTEB UEC25 I973 1 SEAL SLEEVE FOR OIL SEPARATOR BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hermetically sealed motor-compressor units in which high pressure discharge refrigerant gas from the compressor is utilized for motor cooling. The invention more particularly relates to a device for separating entrained oil from the refrigerant gas.

2. Description of the Prior Art It has become common practice to utilize the high pressure discharge gas from a compressor unit for cooling the compressor motor in hermetically sealed motorcompressor units. In a typical hermetically sealed unit, the motor and compressor are mounted on a common shaft which is journaled in a bearing structure mounted within an outer casing. The bottom of the casing generally serves as a reservoir for lubricating oil which is pumped under pressure to the interface between the common shaft and the bearing. Thus, the atmosphere in the casing contains a considerable amount of lubricating oil which becomes entrained in the refrigerant gas used for motor cooling. It is essential for proper operation of the compressor that the entrained oil be separated from the gas prior to its discharge from the hermetically sealed unit and that the oil be returned to the reservoir in the bottom of the casing.

Heretofore, various devices were developed for centrifugally separating the oil from the refrigerant gas. These devices were generally positioned above the motor for intercepting the flow of oil laden refrigerant gas after the gas passed through the motor windings.

One example of such a device is shown in U.S. Pat. No. 3,176,914 issued to D. C. Rinehart and entitled Hermetically Sealed Compressor Unit." In the Rinehart Patent, a circular disc is mounted to a rod which is fixed to the motor shaft. The disc rotates with the rotor and functions to intercept an upwardly flowing stream of discharge gas so that the oil entrained with the gas impinges on the rotating disc and is flung centrifugally against the stator windings. The oil then runs in a downwardly direction through and along the stator windings to the oil reservoir in the lower portion of the casing. As the oil flows through the stator windings, it provides a degree of cooling to the windings in addition to the cooling provided by the passage of discharge gas through the windings.

In the Rinehart Patent, a gas discharge tube is positioned above the rotating disc for receiving the high pressure refrigerant gas from the unit and delivering it to the refrigeration system..The refrigerant gas must flow around the rotating disc and through a narrow air gap between the disc and the stator windings thereby impeding the gas flow to a considerable extent and reducing the efficiency of the compressor unit. As the gas passes through the narrow air gap, it develops an increased velocity and has a tendency to pick up oil that is deposited on the stator windings adjacent the air gap. Thus, some of the oil which was separated from the refrigerant is picked up by the high velocity refrigerant gas thereby reducing the effectiveness of the oil separator.

SUMMARY OF TI-IE'INVENTION The present invention contemplates a hermetically sealed motor-compressor unit which utilizes compressor discharge gas for motor cooling and includes an oil separator. The motor-compressor unit is divided into two chambers, one containing the compressor and the other the motor. The compressor includes a discharge port which is in communication with the motor chamber so that the discharge gas passes into the motor chamber and flows through the stator and rotor windings of the motor to a discharge tube positioned at an opposite end of the motor chamber. The gas passing through the rotor and stator windings absorbs heat therefrom and thereby provides cooling for the motor.

The motor and compressor are mounted on a common shaft which is journaled in a bearing structure mounted within the casing of the motor-compressor unit. A lubricating system provides oil to the interface between the shaft and bearing surfaces and this oil eventually escapes into the motor chamber where it is picked up and entrained in the high pressure refrigerant discharge gas from the compressor. It is essential that the lubricating oil be separated from the refrigerant gas prior to the gas being circulated through the refrigeration system and returned to the compressor intake. Slugging results when liquid oil enters the compressor intake and this greatly reduces compressor life and efficiency.

In order to overcome problems associated with the prior art devices, the present invention provides a circular rotor plate that is attached to an end of the rotor and has an opening formed in the center portion thereof. A discharge tube extends through the opening to a position below the rotor plate and between the rotor windings. By positioning the end of the discharge tube below the rotor plate, the discharge gas flow is unimpeded and a pressure reduction does not result. Lubricating oil entrained in the gas impinges on the rotor plate and is flung in an outwardly direction against the stator windings where the oil flows down through the stator windings to provide additional cooling for the motor. Since the discharge gas does not have to pass between the narrow gap between the rotor plate and the stator windings, the separated oil is not remixed with the gas as in many of the prior art devices.

A flanged sleeve is placed around the discharge tube and is positioned to close a gap between the discharge tube and the rotor plate thereby preventing the flow of discharge gas through the gap. The flange also prevents oil from running down the stationary discharge tube to its open end where it would be sucked into the tube by the discharge gas.

The unique design of the flanged sleeve facilitates assembly of the motor-compressor unit and allows for the use of components having reduced tolerances. Ideally, the gap between the discharge tube and the rotor plate should be minimal; however, there was a tendency for the rotating rotor plate to rub against the stationary discharge tube causing the metal to chip. These chips would eventually cause failure of the compressor. The use of the flanged sleeve allows for a greater space between the discharge tube and the rotor plate thereby preventing contact between the rotor plate and discharge tube.

The primary objective of the present invention is to provide a motor-compressor unit having a more effective oil separator.

Another objective of the present invention is to provide an oil separator for a motor-compressor unit that is less expensive and easier to assemble than those heretofore provided.

Another objective of the present invention is to provide an oil separator for a motor-compressor unit that provides minimal restriction of the discharge gas flow.

The foregoing objectives and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing, wherein one embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for illustrative purposes only and is not to be considered as defining the limits of the invention.

DESCRIPTION OF THE DRAWING FIG. 1 is a partial vertical section of a motorcompressor unit.

FIG. 2 is a vertical section of the flanged sleeve utilized in the compressor of FIG. 1.

FIG. 3 is a plan view of the flanged sleeve of FIG. 2.

FIG. 4. is an elevation view of a flanged sleeve of FIG. 3.

DESCRIPTION OF THE INVENTION Referring to FIG. 1, there is shown a portion ofa motor-compressor unit having a hermetically sealed case enclosing the motor-compressor. A bearing plate 12 is mounted within case 10 and divides the case into a motor chamber 14 and a compressor chamber 16. A compressor 18 is mounted in compressor chamber 16 and a motor 20 is mounted in motor chamber 14.

Plate 12 has a bearing 22 through which is journaled a common shaft 24 which extends into both the motor and compressor chambers. A roller, not shown, of compressor 18 and a rotor 26 of motor 20 are mounted to the shaft in their respective chambers. Motor 20 has a stator 28 mounted within case 10 concentric with rotor 26.

Shaft 24 has lubrication passages 30 formed therein to facilitate delivery of lubricating oil to the interface between the shaft and bearing 22. Compressor 18 includes a pump 19 for delivering lubricating oil under pressure to passages 30 from a reservoir of oil 21 contained in the bottom of case 10. Plate 12 has a port 32 formed therein so that lubricating oil from the motor chamber may return to the compressor chamber to be deposited in the reservoir formed in the bottom of casing 10.

For cooling purposes, compressor 18 has a discharge port 34 for providing high pressure discharge refrigerant gas to motor chamber 14 so that the gas flows through the motor chamber and around the rotor and stator to extract heat therefrom and thereby cool the motor. To this end, the rotor is provided with longitudinally extending openings therethrough as is commonly practiced in the art.

A counterweight 36 extending partially about the rotor is attached to one end of rotor 26 for balancing the rotor to prevent undesirable vibration. A rotor plate 38 is also connected to the end of rotor 26 by the use of screws 40. Rotor plate 38 is circular and has a circular opening 42 formed in the center portion thereof. A gas discharge tube 44 enters case 10 through a seal 46 and extends in a downwardly direction through opening 42 to a position below plate 38 and between the rotor windings 48 of rotor 26. Gas discharge tube 44 has an open end 50 positioned adjacent an end 52.0f shaft 24.

To prevent contact between discharge tube 44 and rotor plate 38, opening 42 is made considerably larger than the outside diameter of discharge tube 44 so as to provide a space between the tube and plate of about one-eighth inch. Thus, the discharge tube and rotor plate may be manufactured to less stringent tolerances at a reduced cost. During assembly the positioning of the rotor relative to the discharge tube becomes less critical and thereby reduces assembly time and cost. A flanged sleeve 54 is disposed about discharge tube 44 for closing the space between the discharge tube and rotor plate.

Flanged sleeve 54 is shown in greater detail in FIGS. 2 through 4. The inside diameter of a sleeve portion 55 is slightly larger than the outside diameter of discharge tube 44 so that the sleeve may be easily slid onto the tube. The sleeve portion has a U-shaped cutout 56 that defines a tab 58 which is bent in an inwardly direction to form a spring for retaining flanged sleeve 54 on the discharge tube by spring tension. The lower end of sleeve portion 55 terminates in an outwardly extending flange 60 having an outer diameter greater than the opening 42 formed in rotor plate 38.

During assembly of motor-compressor unit, flanged sleeve 54 is positioned so that the flanged portion 60 is in contact with rotor plate 38. During the initial rotations of the rotor, the uneveness of the rotor plate and vertical vibrations of the rotor cause the flanged sleeve to slide a slight distance away from the rotor plate. Thus, a minimum spacing between the flange 60 and the rotor plate is provided without contact being made on subsequent rotation.

In another embodiment, the rotor plate may be formed with three or more dimples on the top surface. Initially, the dismples contact the flanged portion, but the dimples wear away during the first few rotations and the rubbing disappears providing a minimal space between the flange and the rotor plate.

During operation of the motor-compressor unit, lubricating oil is supplied to the lubricating passages 30 so that the oil flows along the interface of shaft 24 and bearing 22 and escapes into the motor chamber 14 through the space 37 defined opposite the counterweight between the rotor plate 38 and the top of the rotor windings 48. High pressure discharge refrigerant gas from compressor 18 is provided to the motor chamher through port 34. The gas flows through and around the rotor and stator windings to extract heat therefrom and provide essential motor cooling. As the gas flows through the rotor and stator windings, the lubricating oil becomes entrained therein so as to flow in an upwardly direction with the gas. As the gas flows through and between the windings, it eventually impinges on the rotor plate where the oil is deposited and is thereafter flung under centrifugal force into the stator windings 28. The oil then flows down through the windings unto plate 12 and through port 32 into compressor chamber 16 and reservoir 21. As the oil passes through the stator windings, an additional amount of cooling is provided.

Since the open end 50 of the discharge tube is positioned adjacent end 52 of shaft 24, the discharge gas does not flow directly into the discharge tube but tends to impinge upon rotor plate 38 prior to entering the discharge tube. However, the gas does not have to flow through narrow gaps which greatly impede the flow as in the devices of the prior art. Flanged sleeve 54 provides a seal to prevent gas flow through opening 42 and also prevents oil from running down the sides of the stationary discharge tube where it may be sucked into the open end 50 of the tube.

Thus, the present invention provides a more effective oil separator that does not impede the flow of discharge gas and thereby reduce the compressor efficiency. The invention allows for reduced component and assembly tolerances thereby greatly reducing the assembly time and cost of a motor-compressor unit.

What is claimed is:

1. A motor-compressor unit comprising:

a sealed case;

a bearing plate,including a bearing, mounted in said case to divide the case into a compressor chamber and a motor chamber;

a shaft journaled in said bearing and extending into both the motor chamber and compressor chamber;

compressor means mounted in said compressor chamber and drivably attached to said shaft for providing compressed refrigerant gas to said motor chamber;

means for providing lubricating oil to the interface between the shaft and the bearing;

a motor having a rotor attached to said shaft and a stator mounted to said case in the motor chamber;

a rotor plate attached to the end of said rotor opposite the bearing, said rotor plate having an opening formed in the center thereof and said rotor plate being spaced apart from said rotor end;

a gas discharge tube extending into said case and through the opening formed in the rotor plate; and

a flanged sleeve slidably mounted to said discharge tube for closing a space between the discharge tube and the rotor plate, whereby lubricating oil entrained in the discharge gas impinges on the rotor plate and is flung under centrifugal force in an outwardly direction towards said stator windings through the spacing between said rotor plate and rotor end.

2. A motor-compressor unit as described in claim 1, wherein the compressor means includes a port communicating the compressor with the motor chamber.

3. A motor-compressor unit as described in claim 1, wherein the discharge tube is in axial alignment with the shaft and has an open end positioned adjacent an end of the shaft.

4. A motor-compressor unit as described in claim 1, wherein the rotor plate additionally includes counterweights disposed between the rotor plate and rotor for balancing the rotor.

5. A motor-compressor unit as described in claim 1, wherein the flanged sleeve comprises:

a sleeve portion formed and arranged to be slid over the discharge tube; and

a flanged portion formed at one end and extending in an outwardly direction for closing the space between the discharge tube and the rotor plate.

6. A motor-compressor unit as described in claim 1, additionally comprising spring means associated with the flanged sleeve for maintaining the flanged sleeve in position about the gas discharge tube.

7. A motor-compressor unit as described in claim 5, wherein the sleeve portion includes spring means for maintaining the sleeve in position on the gas discharge tube.

8. A motor-compressor unit as described in claim 7, wherein the spring means comprises an inwardly bent tab formed on the sleeve.

UNITED STATES PATENT OFFICE CERTIFICATE. OF CORRECTION pat No 3,781,138 Dated December 25, 1973 Invntm-(S) Friedrich Otto Bellmer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Inventor's name is misspelled. "Frederich" should be changed to--Friedrich--;

Col. 4, line 37, "dismples" should be--dimples-- and line 57, "into" should be--u nto- Signed and sealed this ll th day of May 19714..

(SEAL) At ts s t EDWARD M.FLETCHER, JR. C MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-P69 rs GOVERNMENT PRINTING orHc: In" o-ass-su FORM Po-wso (1M9)

Claims

1. A motor-compressor unit comprising: a sealed case; a bearing plate, including a bearing, mounted in said case to divide the case into a compressor chamber and a motor chamber; a shaft journaled in said bearing and extending into both the motor chamber and compressor chamber; compressor means mounted in said compressor chamber and drivably attached to said shaft for providing compressed refrigerant gas to said motor chamber; means for providing lubricating oil to the interface between the shaft and the bearing; a motor having a rotor attached to said shaft and a stator mounted to said case in the motor chamber; a rotor plate attached to the end of said rotor opposite the bearing, said rotor plate having an opening formed in the center thereof and said rotor plaTe being spaced apart from said rotor end; a gas discharge tube extending into said case and through the opening formed in the rotor plate; and a flanged sleeve slidably mounted to said discharge tube for closing a space between the discharge tube and the rotor plate, whereby lubricating oil entrained in the discharge gas impinges on the rotor plate and is flung under centrifugal force in an outwardly direction towards said stator windings through the spacing between said rotor plate and rotor end.

5. A motor-compressor unit as described in claim 1, wherein the flanged sleeve comprises: a sleeve portion formed and arranged to be slid over the discharge tube; and a flanged portion formed at one end and extending in an outwardly direction for closing the space between the discharge tube and the rotor plate.