[go: up one dir, main page]

US3560116A - Enclosed motor-compressor,particularly a small refrigerating machine - Google Patents

Enclosed motor-compressor,particularly a small refrigerating machine Download PDF

Info

Publication number
US3560116A
US3560116A US795267*A US3560116DA US3560116A US 3560116 A US3560116 A US 3560116A US 3560116D A US3560116D A US 3560116DA US 3560116 A US3560116 A US 3560116A
Authority
US
United States
Prior art keywords
oil
motor
shaft
compressor
pump
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US795267*A
Other languages
English (en)
Inventor
Kund V Valbjorn
Hans Ulrik Leffera
Heinz Mahncke
Bendt Wegge Fomer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Danfoss AS
Original Assignee
Danfoss AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Danfoss AS filed Critical Danfoss AS
Application granted granted Critical
Publication of US3560116A publication Critical patent/US3560116A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/02—Compressor arrangements of motor-compressor units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
    • F04B39/02—Lubrication
    • F04B39/0223—Lubrication characterised by the compressor type
    • F04B39/023—Hermetic compressors
    • F04B39/0238—Hermetic compressors with oil distribution channels
    • F04B39/0246—Hermetic compressors with oil distribution channels in the rotating shaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D1/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D1/14—Pumps raising fluids by centrifugal force within a conical rotary bowl with vertical axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/002—Lubrication
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/12—Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas

Definitions

  • This invention relates generally to hermetic motorcompressors and more particularly to small encapsulated refrigeration machines.
  • Refrigeration compressors having a vertical crank shaft and a motor positioned below the compressor are known wherein a positive displacement pump at the lower end of the crankshaft delivers oil from the oil sump through an immersion tube and feeds it to various lubricating points such as shaft bearings, crank bearings and the compressor cylinder.
  • the surplus oil is flung vertically upwardly against the inner wall surfaces of the unit capsule so that it is cooled thereon and runs along the wall of the capsule back into the oil sump at the lower end of the capsule.
  • the motor rotor and stator are provided with dished receiving elements into which oil emerging from the lubricated parts can collect. The collected oil is applied to the motor for cooling the stator winding.
  • this type of cooling has several deficiencies in that the quantity of oil delivered to the winding per unit time is very small because a considerable throttling effect occurs at the lubrication point passages. Furthermore, the oil has a very high temperature since it has picked up a considerable amount of heat lubricating the various parts, particularly oil lubricating the cylinder which is very hot. This heated oil is then used as a cooling medium and it is not as effective as it should be for cooling the motor and stator.
  • the refrigerant in a gaseous state within the capsule has had to effect part of the cooling and particularly parts of a motor-compressor such as the motor rotor and stator.
  • This gas cooling is, however, dependent upon the particular conditions of operation and is often insufiicient at low evaporation temperatures.
  • Another object of the present invention is to provide a method of oil cooling independent of operating conditions in the external circuit of a refrigeration apparatus, thereby to reduce the great necessity of refrigerant gas cooling in the refrigeration compressor.
  • oil is delivered by a centrifugal pump as two streams independent of each other.
  • One of the oil flows is for lubricating in the usual manner and the other stream cools motor parts directly.
  • the best cooling is effected by delivering a sufiicient quantity of cooling oil.
  • the total quantity of oil circulated should be at least liters/H.P.-hour. The value of this quantity is greater than that of existing machines by approximately one order of magnitude.
  • the invention is applied to motor-compressor units having a vertical motor shaft with the compressor disposed above the motor and the shaft having a bore through which oil flows axially and outwardly therefrom to various lubricating points.
  • the shaft is provided with one or two centrifugal pumps for delivering oil to independent oil flows for lubrication and cooling of the apparatus.
  • one pump In the embodiment in which one pump is used, it is constructed as a tube coaxial with the shaft and depending therefrom.
  • the tube is provided with a conical lower end having an opening of lesser diameter than the diameter of the tube.
  • a part of the axial length of the tube has an increased diameter and an opening for delivery of a stream of oil therefrom applied to passageways in the rotor for delivery to the stator with suitable deflecting means and cooling thereof.
  • the remainder of the flow from the tube passes upwardly through the shaft bore and is applied through suitable passages to the parts to be lubricated.
  • the centrifugal pump is constructed as two coaxial tubes with the inner tube depending from the shaft and the outer tube spaced outwardly therefrom defining a space between the two tubes. Both tubes are provided with a conical lower end portion so that upon rotation thereof in common with the water shaft oil flows through the inner tube upwardly through the shaft for lubrication and cooling oil flows between the two tubes and is delivered to a chamber defined between a lower short-circuiting ring and an upper end flange on the outer tube from where oil flows upwardly through axial passages in the rotor and onto the stator.
  • the axial passageways formed in the stator are inclined from the vertical and in a direction opposite to the direction of rotation of the motor in order to improve the fiow of oil therethrough.
  • the motor lower shortcircuiting ring or a deflector cooperative therewith in either embodiment is preferably provided with radial passages providing communication from the oil pump to the outer periphery of the rotor and delivery of oil to the lower ends of the stator which is axially longer than the rotor and is disposed circumferentially thereof.
  • the axial bore of the shaft is in communication with upwardly extending axial passageways opening to the top of the shaft where a centrifuging disc is mounted that flings upwardly and outwardly the oil onto the inner wall of the capsule where cooling takes place as it works its way downwardly back to the sump at the lower end of the capsule.
  • one of these passages is a direct passage without communication with other transverse passages providing lubricating oil.
  • the upwardly extending passages in communication with lubricating passages apply excess oil to the centrifuging disc for cooling of the sulplur oil, as above described.
  • a deflector or receiving device is provided near the lower outer edge of the stator for gathering the oil flow of the discharged oil flowing over the stator and oil entering therein bathes the lower coil ends.
  • FIG. 1 is a longitudinal section through a motor-compressor unit embodying the invention
  • FIG. 2 is a cross-section view taken along section line AA in FIG. 1;
  • FIG. 3 is a cross-section view through a rotor of another embodiment of the invention.
  • FIG. 4 is a fragmentary longitudinal section view of a modification of the invention illustrating a modified centrifugal pump for delivery of lubricating and cooling oil as two independent outputs.
  • a motor-compressor unit comprises a hermetic capsule 1 in which is resiliently suspended, by a suspension system not shown, a refrigeration machine constituting a compressor having a downwardly extending portion 2 which supports a stator 5 of an electric drive motor and defines a bearing 3 for a shaft 4 of the motor.
  • Upward extensions 6 on the motor support 2 form noise-reducing or absorbing chambers 7 of the compressor and a cylinder having an axis perpendicular to the plane of the drawing.
  • a support plate 13 supports the shaft vertically and a centrifuging disc or slinger ring 14 fixed to the rotatably driven shaft by a bolt 15, as illustrated.
  • the shaft 4 carries on a crank a crank bearing 11 to which is connected a connecting rod of a compressor piston, not shown.
  • the motor has a rotor 12 mounted on the shaft 4. This rotor is provided with an upper shortcircuiting ring 16 and a lower short-circuiting ring 17.
  • the motor stator 5 has upper coil ends 18 extending axially upwardly of the rotor and lower coil ends 19 extending and projecting axially downwardly of the rotor.
  • the motor shaft 5 has an axial bore 20 into which a first length of tubing 21 is inserted axially.
  • the tubing extends axially downwardly and provides communication between it and the bore of the shaft and a hollow conical element or lower end portion 22 rotationally driven with the shaft 4 to function as a centrifugal oil pump.
  • a transverse opening or passage 23 extends from the shaft bore 20 for lubricating the bearing 3 and three parallel axial passages or bores of reduced diameter 24, 25 and 26 extend axially upwardly from the main axial bore and terminate within the centrifuging disc .14, as illustrated in the drawings.
  • a branch passage 27 for lubricating the crank bearing 11 extends from the bore 24 and another branch lubricating passage 28 for applying lubricating oil to the upper bearing 9 is in communication with the bore 26.
  • Surplus oil not entering the branch passages along with the oil from the through passage 25 passes upwardly to the inside of the centrifuging disc 14 and is flung onto the inner wall of the capsule 1 over which it flows back into an oil sump 42 and is cooled in so doing.
  • a second length of tubing 29 is mounted on the first length of tubing 21 outwardly thereof and spaced therefrom extending axially of the inner or first length of tubing.
  • the outer tubing is provided with a number of circumferentially spaced axially extending depressions 30 which extend radially inwardly defining inwardly-extending projections parallel with the axis of the two tubes to function as spacing elements and mounting the second length of tubing onto the inner or first length of tubing 21.
  • This outer length of tubing is provided at the lower end thereof with a hollow conical element or lower end portion 31 which terminates in an opening disposed axially spaced upwardly of an opening of the hollow conical element 22.
  • the second hollow conical element 31 functions as a second centrifugal pump to deliver oil upwardly by way of centrifugal action and delivers oil in the space formed between the two tubes.
  • the upper end of the tube 29 is bent over outwardly to form a flange 32 which closely contacts the lower shortcircuiting ring 17, except at circumferentially spaced points where it has radial depressions defining radial passages 33.
  • a cavity 34 from which passages 35 extend upwardly through the rotor 12.
  • the rotor support 2 forms a receiving wall 36 which surrounds the stator upper coil ends 18 and which is provided at its lower end with radial orifices or passages 37 so that the cooling oil entering a space 38, defined by the stator and its support, can be discharged over the outer periphery of the stator.
  • a receiving and deflecting device 39 which receives the oil discharged through the outlets 37 and bathes the lower coil ends 19.
  • the device 39 can be constructed, for example, as a ring of sheet metal which is clamped onto the stator 5 by means of individual, circumferentially spaced, inwardly extending, ribs.
  • a cavity 40 in the insert 7 communicates with the space 38 by way of openings 41, so that oil emerging from the lubricated parts can likewise flow away back to the sump by way of the space 38.
  • the hollow conical element 22 supplies sufficient oil from the sump 42 in the usual manner, so that the lubrication points of the bearings and cylinder are properly lubricated. Furthermore, the surplus oil passes upwards through the three axial bores 24-26 and into the dished plate 14 and is slung onto the wall of the capsule 1. The oil is subjected to extensive cooling during its flow along the wall of the casing back to the sump 42.
  • the second hollow conical element 31 delivers cooling oil through the chamber or space between the two coaxial tubes 21 and 29 into the annular chamber 34.
  • the cooling oil passes upwards through the axial passages 35 and is flung by the short-circuiting ring 16 onto the stator upper coil ends 18.
  • a second portion or flow of the cooling oil passes outwards through the radial passages 33 and is flung onto the stator lower coil ends 19.
  • Some upwardly flung cooling oil flows downwards through the gap between the rotor and the stator; the greater volume, however, is received by the wall 36 and flows downwardly through the orifices 37 along the outer periphery of the stator 5 where it is received by the receiving device 39 and is additionally distributed over the stator lower coil ends 19.
  • the inner pump i.e. the hollow conical element 22
  • the inner pump delivered fifty-eight liters per hour, of which about 12 liters per hour were used for lubrication and about thirty-six liters per hour flwe dodwnthe and about thirty-six liters per hour flowed down the wall of the casing for return cooling.
  • the outer pump i.e. the hollow conical unit 31, on the other hand, delivers about eighty liters per hour, principally because of the greater effective diameter of the cone.
  • FIG. 4 illustrates a single centrifugal pump, wherein the oil is divided into two streams at the level of the lower edge of the rotor.
  • a tube 45 comprising a lower hollow conical element 46 has a protuberance 47 at its upper end which bears against the short-circuiting ring 17.
  • Opening 48 on the upper side of the protuberance 47 and circumferentially spaced thereon enable part of the oil from the pump to enter a chamber 49 and from there to pass into the passages 35 in the stator. Since additional drive or force results from the extension 47, the stream of oil branching off through the openings 48 is greater than the stream of oil rising through the shaft axial bore 20.
  • a motor having a vertically disposed motor shaft for driving the motor-compressor unit, a rotor connected to said shaft and a stator circumferentially of said rotor, pump means driven by said shaft delivering two independent flows of oil, one flow for lubricating said unit and another for cooling said rotor and stator without flowing cooling or lubricating other components of said unit, said pump means comprising two centrifugal oil pumps driven in common by said shaft, said two centrifugal oil pumps comprising two coaxial tubes defining a suction space therebetween, said tubes each having a conical lower end portion, said shaft having a bore, an inner one of said tubes being disposed.
  • each of said tubes comprises a conical lower end portion, each portion having an opening having a diameter less than the diameter of each respective tube.
  • the outer one of said two coaxial tubes comprises an upper end outwardly extending flange engaging said lower short-circuiting ring defining an annular chamber jointly with said rotor, said short-circuiting ring and said shaft, said chamber communicating with said space, and said passages communicating with said chamber.
  • said motor-compressor comprises a dished member connected to an upper end of said shaft, said shaft having oil passageways providing communication between the interior of said dished member and said bore, a capsule hermetically enclosing said motor-compressor, and said dished member being disposed relative to the interior of said capsule in position for flinging oil therefrom onto inner wall surfaces of said capsule for cooling thereon.
  • motor-compressor unit in which said motor-compressor comprises a downwardly extending support wall member outwardly of said rotor upper end, said support wall having openings spaced thereon in a circumferential direction for allowing oil to flow therethrough onto the outer periphery of said stator.
  • a motor-compressor unit including a dished receptor disposed under the lower end of said stator to receive oil flowing over the periphery of said stator for cooling said lower end of said stator.
  • said pump means comprises a tube disposed as an extension of said shaft, said shaft having an axial bore in communication with said tube, said tube having an enlarged portion having an enlarged diameter along an axial length thereof, said enlarged portion having a plurality of openings spaced in a circumferential direction, said tube having a conical lower end converging in a direction inwardly of the tube, said conical lower end having an opening for taking an oil suction when said tube is driven rotationally by said shaft, and one of said oil flows flowing upwardly through said bore and said another flow flowing outwardly through said openings.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Power Engineering (AREA)
  • Compressor (AREA)
  • Motor Or Generator Cooling System (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US795267*A 1968-02-01 1969-01-30 Enclosed motor-compressor,particularly a small refrigerating machine Expired - Lifetime US3560116A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1628157A DE1628157C3 (de) 1968-02-01 1968-02-01 Einrichtung zum Kuhlen eines ge kapselten Motorverdichters, insbesondere Klemkaltemaschine

Publications (1)

Publication Number Publication Date
US3560116A true US3560116A (en) 1971-02-02

Family

ID=5683138

Family Applications (1)

Application Number Title Priority Date Filing Date
US795267*A Expired - Lifetime US3560116A (en) 1968-02-01 1969-01-30 Enclosed motor-compressor,particularly a small refrigerating machine

Country Status (7)

Country Link
US (1) US3560116A (es)
BR (1) BR6906029D0 (es)
DE (1) DE1628157C3 (es)
ES (1) ES362828A1 (es)
FR (1) FR2001153A1 (es)
GB (1) GB1226311A (es)
SE (1) SE350807B (es)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4565503A (en) * 1982-10-12 1986-01-21 Tecumseh Products Company Device for cooling motor end-turns in a compressor
US4907951A (en) * 1988-09-16 1990-03-13 Tecumseh Products Company Foreign particle trap for a compressor
USRE34297E (en) * 1988-06-08 1993-06-29 Copeland Corporation Refrigeration compressor
EP1055820A1 (en) * 1999-05-26 2000-11-29 Mitsubishi Heavy Industries, Ltd. Scroll machine lubrication system
US20080069714A1 (en) * 2006-09-14 2008-03-20 Bonifas Mark A Compressor having counter-weight cup
CN102734170A (zh) * 2011-04-15 2012-10-17 艾默生环境优化技术有限公司 旋转式压缩机
WO2016070897A1 (en) * 2014-11-03 2016-05-12 Arcelik Anonim Sirketi Improved lubricating device for use in a hermetic compressor
CN106979141A (zh) * 2016-01-19 2017-07-25 惠而浦股份有限公司 在冷却压缩机中的油泵组件装置
WO2021142525A1 (pt) * 2020-01-17 2021-07-22 Embraco Indústria De Compressores E Soluções Em Refrigeração Ltda. Sistema de transporte de óleo lubrificante em compressor
US20230014696A1 (en) * 2019-12-11 2023-01-19 Nidec Global Appliance Brasil Ltda. Reciprocating hermetic compressor with axial flux motor
EP4435261A1 (en) * 2023-03-21 2024-09-25 Secop GmbH Refrigerant compressor
EP4435260A1 (en) * 2023-03-21 2024-09-25 Secop GmbH Refrigerant compressor

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1205058A (en) * 1982-10-12 1986-05-27 Kennard L. Wise Device for cooling motor end-turns in a compressor
DE19510015C2 (de) * 1995-03-20 1997-04-30 Danfoss Compressors Gmbh Ölpumpe, insbesondere für einen hermetisch gekapselten Kältemittelkompressor

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4565503A (en) * 1982-10-12 1986-01-21 Tecumseh Products Company Device for cooling motor end-turns in a compressor
USRE34297E (en) * 1988-06-08 1993-06-29 Copeland Corporation Refrigeration compressor
USRE37019E1 (en) 1988-06-08 2001-01-16 Copeland Corporation Refrigeration compressor
US4907951A (en) * 1988-09-16 1990-03-13 Tecumseh Products Company Foreign particle trap for a compressor
EP0358926A1 (en) * 1988-09-16 1990-03-21 Tecumseh Products Company Foreign particle trap for a compressor
EP1055820A1 (en) * 1999-05-26 2000-11-29 Mitsubishi Heavy Industries, Ltd. Scroll machine lubrication system
US20080069714A1 (en) * 2006-09-14 2008-03-20 Bonifas Mark A Compressor having counter-weight cup
US7413423B2 (en) * 2006-09-14 2008-08-19 Emerson Climate Technologies, Inc. Compressor having a lubrication shield
CN102734170A (zh) * 2011-04-15 2012-10-17 艾默生环境优化技术有限公司 旋转式压缩机
WO2016070897A1 (en) * 2014-11-03 2016-05-12 Arcelik Anonim Sirketi Improved lubricating device for use in a hermetic compressor
CN106979141A (zh) * 2016-01-19 2017-07-25 惠而浦股份有限公司 在冷却压缩机中的油泵组件装置
US20230014696A1 (en) * 2019-12-11 2023-01-19 Nidec Global Appliance Brasil Ltda. Reciprocating hermetic compressor with axial flux motor
WO2021142525A1 (pt) * 2020-01-17 2021-07-22 Embraco Indústria De Compressores E Soluções Em Refrigeração Ltda. Sistema de transporte de óleo lubrificante em compressor
US20230065792A1 (en) * 2020-01-17 2023-03-02 Nidec Global Appliance Brasil Ltda. System for transporting lubricating oil in a compressor
EP4435261A1 (en) * 2023-03-21 2024-09-25 Secop GmbH Refrigerant compressor
EP4435260A1 (en) * 2023-03-21 2024-09-25 Secop GmbH Refrigerant compressor
WO2024194438A1 (en) * 2023-03-21 2024-09-26 Secop Gmbh Refrigerant compressor
WO2024194434A1 (en) * 2023-03-21 2024-09-26 Secop Gmbh Refrigerant compressor

Also Published As

Publication number Publication date
GB1226311A (es) 1971-03-24
ES362828A1 (es) 1970-09-01
FR2001153A1 (es) 1969-09-26
SE350807B (es) 1972-11-06
DE1628157A1 (de) 1972-01-05
DE1628157B2 (de) 1973-03-22
BR6906029D0 (pt) 1973-06-12
DE1628157C3 (de) 1973-10-11

Similar Documents

Publication Publication Date Title
US3560116A (en) Enclosed motor-compressor,particularly a small refrigerating machine
US4576555A (en) Oil dispersing device
US3877546A (en) Lubrication system for vertical spindle motor
CA1222990A (en) Direct suction radial compressor
US3285504A (en) Refrigerant apparatus
US2178811A (en) Compression apparatus
US4569639A (en) Oil distribution system for a compressor
US4205537A (en) Multiple hermetic-motor compressor in common shell
US3664461A (en) Oil pump for a motor compressor
US3584980A (en) Two-speed compressor
US4565503A (en) Device for cooling motor end-turns in a compressor
US3454213A (en) Pedestal-supported encapsulated refrigerant motor-compressor unit
CA1216832A (en) Oil cooled, hermetic refrigerant compressor
US3560117A (en) Oil pump for enclosed motor-compressor,especially for small refrigerating machines
US2898072A (en) Lubricating system for refrigerant compressors
US3295753A (en) Refrigerating apparatus
US5707220A (en) Centrifugal oil pump for a variable speed hermetic compressor
EP0754272B1 (en) Oil pump for a variable speed hermetic compressor
US3259307A (en) Hermetic refrigerant compressors
US2844302A (en) Refrigerating apparatus x
US2043215A (en) Unitary motor-pump assembly
US4111612A (en) Hermetic compressor lubrication system
US3587781A (en) Encased motor compressor
US2102391A (en) Refrigerating machine
US4400142A (en) Motor-compressor unit