US2178425A

US2178425A - Refrigerating machine

Info

Publication number: US2178425A
Application number: US126370A
Authority: US
Inventors: Wilfrid E Johnson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1937-02-18
Filing date: 1937-02-18
Publication date: 1939-10-31
Anticipated expiration: 1956-10-31

Description

Oct. 31, 1939. w JOHNSON 2,178,425

REFRIGERATING MACHINE Filed Feb. 18, 1957 2 Sheets-Sheet 1 54 F2; 45 as 4/ Inventor:

Wilfrid E. Johnson,

b 2141/7 9 His Attorney 0 31, 1939. w. E. JOHNSON 2,178,425

REFRIGERATING MACHINE Filed Feb. 18, 1937 2 Sheet-Sheet 2 Inventor: Wilfrid E. John on,

His Attorney- Patented O ci. 3i, 193

UNITED STATES PATENT OFFICE to General Electric New York Company, a corporation of Application February 18, 1937, Serial No. 126,370

4 Claims.

My invention relates to refrigerating machines. Refrigerating machines of the compression type are provided with a compressor having a compression chamber, and a displacement member in 5, the chamber which cooperates therewith to withdraw vaporized refrigerant from an evaporator associated with the machine and discharge the compressed refrigerant into a high pressure refrigerant circuit including a refrigerant condenser. It has been proposed to seal such a compressor against leakage of compressed refrigerant therefrom by maintaining a body of lubricant under pressure in a recess associated with thesealing surfaces of the compression chamber.

13 Difliculty has been encountered, however, in the operation of such sealing arrangement as that described due to the wide variation in the pressure of the compressed refrigerant in the high pressure circuit, over the operating range of the machine. This pressure depends at any particular time upon the amount of refrigeration supplied by the machine, the rate of heat dissipation of the condenser of the machine, and other factors. When the pressure in the high pressure circuit of the machine is relatively high, the

pressure of the compressed refrigerant in the.

compression chamber often exceeds the pressure of the body of sealing lubricant, thus permitting leakage of the compressed refrigerant from the compressor. When the pressure in the high pressure circuit of the machine is relatively low, the pressure of the body of sealing lubricant often greatly exceeds the pressure of the compressed refrigerant in the compression chamber, thus allowing a considerable amount of lubricant to flow from the body of sealing lubricant into the compressor. Under these conditions, not only is the volumetric efliciency of the compressor diminished by the leakage of sealing. lubricant into the compression chamber, which reduces the amount of useful work done by the compressor upon the refrigerant, but the sealing lubricant leaking into the compressor chamber also absorbs compressed refrigerant, thus diminishing the quantity of compressed refrigerant which is discharged into the condenser ofthe machine.

It is an object of my invention to provide arefrigerating machine having a motor and a compressor arranged within a closed casing'and hav- 3 ing an improved lubricating system, and an-imutilizing low pressure for cooling the compressor and utilizing high pressure for sealing the compressor against leakage of compressed refrigerant therefrom.

A further object 'of my invention is to provide 6 a refrigerating machine having a refrigerant compressor and a pressure lubricant system for sealing the compressor against leakage of com-' pressed refrigerant, the pressure of the sealing lubricant being regulated and maintained in re- 10 ponse to the pressure of the compressed refrigerant above the pressure of the compressed refrig erant.

Further objects and advantages of my invention will become apparent as the following description 15 proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexedto and forming a part of this specification.

For a better understanding of my invention go reference may be had to the accompanying drawings in which Fig. l is a side elevation, partly in section, of a refrigerating machine embodying my invention; Fig. 2 is an enlarged side elevation of the rotary compressor of the refrigerating ma- 25 chine; Fig. 3 is an enlarged sectional view on the line 3-3 of Fig. l of the lubricant Pump of the refrigerating machine; Fig. 4 is a sectional view on the line 4-4 of Fig. 3 of the lubricant pump; and Fig 5 is an enlarged plan view on the line 30 5-5 of Fig. 2 of the rotary compressor of the refrigerating machine.

Referring to the drawings, 1 have shown in Fig. 1a refrigerating machine including a supporting plate or frame l0 and anupper casing sec- 3 tion ll cooperating with the supporting frame in to define an upper chamber I2. The upper casing section II comprises a cylindrical body 13 andia cup-shaped end it sealed thereto by welding. A ring I5 is welded to the open'end 40 of the cylindrical body 13 and is provided with an annular recess thereabout which receives a suitable sealing gasket l6 therein. A similarly constructed lower casing section I'I, comprising a cylindrical body It and a cup-shaped end I9, 45

cooperates with the supporting frame 10 to de-- fine a lower chamber 20. About the open end of thecylindrical body I8 there is secured a ring .25 provided with an annular recess thereabout which receives a suitable sealing gasket 22 therein. The rings l5 and 2! are tightly secured to cooperating sealing surfaces formed on the supporting frame it by a series of bolts 23 passed through holes formed in the sealing rings and the supporting'frame'. The upper and lower casing 5 sections H and I1 may be individually removed from the supporting frame ID for purpose of inspection in the upper and lower chambers l2 and 20, respectively. When these casing sections are secured in place upon the supporting frame In, a hermetically sealed casing is provided for housing the refrigerant circulating elements of the refrigerating machine as will be hereinafter described.

The supporting frame I0 is provided with a centrally disposed boss 24 having a bearing 24a in which a drive shaft 25 is'journaled and which extends into the upper and lower chambers I2 and 20, respectively. An annular flange 26 is provided about the supporting frame It) in spaced relation to the centrally disposed boss 24, and

cooperates therewith to define an annular recess 21 extending about the supporting frame I0 and constituting a lubricant reservoir. An electric motor is arranged in the upper chamber l2, and comprises a stator 28 which is supported by an annular ring 29 secured to the flange 26, and a rotor 30 secured to the upper end of the drive shaft 25. The rotor 30 of the electric motor is preferably of the squirrel-cage type, and the stator 28 is provided with a winding 3| connected to a suitable source of supply. A deflecting baffle 32 of cup-shaped configuration is secured to the upper end of the stator 28 in order to prevent lubricant discharged into the upper chamber l2 from flowing into the air gap between the rotor and the stator of the electric motor. The end turns of the stator windings 3| at the lower end of the electric motor are arranged to extend into the annular recess 21 formed in the supporting frame l0. An opening 33 formed in the flange 26 affords a communication between the lower portion of the interior of the chamber l2 and the interior of the annular recess 21.

A rotary type refrigerant compressor 34 and a lubricant pump 35 are arranged in the lower chamber 20 and are operated by the lower portion of the drive shaft 25 extending through the opening 24a in the centrally disposed boss 24 on the supporting frame l0. As best shown in Figs. 2 and 5 the compressor 34 is provided with a cylindrical body 36 having

flanges

31 and 38 about its upper and lower ends, respectively. The upper end of the block 36 is secured to the lower surface of the supporting frame l0 about the drive shaft 25 by a series of bolts 39 extending through holes formed in the upper flange 31 and threaded into holes provided in the supporting frame I0. vided with a casing having a flange 4| about its upper end, the flange 4| being secured to the flange 38 on the lower end of the compressor body. A cylindrical bore or compression chamber 42 is formed in the compressor body 35 and extends therethrough between the lower surface of the supporting frame In and the upper surface of the lubricant pump casing 40, which surfaces constitute cylinder heads for the bore 4 2. These cylinder heads and the body 38 thus comprise a casing for the compressor 34. A rotor or displacement member 43 is provided on the lower end of the drive shaft 25, preferably being formed integral therewith, and arranged in the bore 42. The bore 42 is disposed eccentric with respect to the center .line of the drive shaft 25 and the rotor 43 is disposed concentric with respect to the-center line of the drive shaft 25. The rotor 43 contacts the cylindrical wall of the bore 42 along a line indicated at 44 in Fig. 5, thus defining a crescent-shaped chamber within the The lubricant pump 35 is probore 42 in which gaseous refrigerant is compressed. Intake and

exhaust ports

45 and 45, respectively, are arranged in the block 36 on opposite sides of the line 44 and in communication with the ends of the crescent-shaped chamber in the bore 42. A plurality of radially disposed slots 41 are formed in the rotor 43 which receive a plurality of slidable blades 48 therein, the outer ends of the blades being in contact with the cylindrical wall of the bore 42.

The drive shaft 25 extends below the rotor 43 and is journaled in an opening 40a formed in the casing 40 of the lubricant pump 35. Adjacent the upper end of the rotor 43 and the lower surface of the supporting frame I0 an annular recess'43 is formed in the drive shaft 25. A similar annular recess is formed in the drive shaft 25 adjacent the lower end of the rotor 43 and the upper surface of the casing 40 of the lubricant pump. Each of these annular recesses contains a body of lubricant under relatively high pressure for sealing the bore 42 against leakage of compressed refrigerant. Also, the lubricant in therecess 49 lubricates the portion of the drive shaft 25' above the rotor 43 which is journaled in the opening 24a in the boss 24 on the supporting frame If], while the lubricantjin the recess 50 lubricates the portion. of the drive shaft 25 below the rotor 43 which is journaled in the opening 40a in the casing 40 of the lubricant pump 35.

During the operation of the compressor, vaporized gaseous refrigerant is drawn into the compressor through an inlet conduit 5| connected to the intake port 45 and compressed in the crescent-shaped chamber extending between the intake port 45 and the exhaust port 46 by the blades 48 slidably carried by the slots 41 in the rotor 43. The compressed refrigerant is then discharged from the compressor through the exhaust port 46. into a mufller 52 secured to the compressor, from which it flows through an outlet conduit 53.

As best shown in Figs. 3 and 4, a cylindrical bore 54 is arranged in the lower end of the casing 40 of the lubricant pump 35. The bore 54 is somewhat larger than the bearing 40a and is disposed eccentric with respect thereto and the center line of the drive shaft 25. The extreme lower end 25aof the drive shaft 25 is arranged in the bore 54 and constitutes a rotor for the lubricant pump. A slot 55 is formed in the rotor 25a which receives a pair of diametrically disposed slidable blades 56. The casing 40 is provided with an inlet port 51 communicating with the bore 54, a low pressure discharge port 58 and a high pressure discharge port 59. A lubricant inlet passage 50 is formed in thecas, ing 4|] and communicates with the inlet port 51, Access may be had to the inlet, port 51 through an opening formed in the casing 40 which is closed by a plug 5| threaded into the casing. The discharge port 58--communicates with a chamber 52 formed in the casing 40 into which compressed lubricant from the bore 54 is discharged through a suitable valve 53. Access may-be had to the interior of the chamber 52 to facilitate inspection of the valve 53 through an opening formed in the casingflt which is closed by a plug 54 threaded into the casing. The dis charge port 59 communicates with a chamber formed in a ,lubricant pressure regulator 36 into which-compressed lubricant from the bore 54 is discharged through a suitable valve 51. Access may be had to the interior of the chamber 65 to facilitate inspection of the valve 61 through an opening formed in the lubricant pressure regulator 66 which is closed by a plug '68 threaded into the lubricant pressure regulator. The valves 63 and 61 are preferably of the flapper type comprising a base having a discharge aperture and a recess formed therein for guiding a valve element arranged to open and close the discharge aperture formed in the base. An end cap 69 is secured to the lower end of the casing 40 by a series of boltsflfl and constitutes a cover plate for the bore 54. The end cap 69 is provided with an opening ll therethrough which is in registry with the lubricant inlet passage 66 formed in .the casing 46. The end cap 69 is also provided with a reticulated screen 12 on the lower end thereof and secured thereto, so as to prevent foreign matter from entering the opening Ii formed therein, The extreme lower end of the rotor 25a is provided with a polished surface normal to the center line of the drive shaft 25 which supports the drive shaft 25 upon a thrust bearing block I3 positioned within the bore 54. The thrust bearing block 13 is resiliently supported by the end cap 69 upon a compression spring 14 positioned in a recess 15 formed in the end cap 69.

The lower end of the lubricant pump 35 is submerged in lubricant contained in a lubricant reservoir i9a formed by the cup-shaped end l9 of the lower casing section I1. During the operation of the lubricant pump, lubricant is drawn into the bore .54 from the lubricant reservoir [9a through the lubricant inlet passage 60 and the The lubricant drawn into the inlet port 51. chamber 54 is pumped by the blades 56 carried by the rotor 25a. A portion of this lubricant is discharged at a relatively low pressure through the discharge port 58 and valve 63 into the chamber 62, while the remainder of this lubricant is. further pumped into the chamber 54 and discharged at a relatively high pressure through the discharge port 59 and valve 61 into the chamber 65 formed in the lubricant pressure regulator 66.

As shown in Figs. 3 and 4, the lubricant pressure regulator 66 is formed integral with the lubricant pump casing 40 and includes a body in which the chamber 65 is formed and in which communicating large area and small area bores 16 and 11-, respectively, are formed. The coinmunicating bores 16 and I1 slidably receive a large area piston 18 and a small area piston. 19, respectively, constituting an integral plunger 80. The small area-bore 1.1 communicates withthe chamber 65 and the large area bore 16 communicates with a conduit 8|, which conduit communicates with the high pressure refrigerant circuit of the machine. A lubricant diverting passage 82 is formed in the body of the lubricant pressure regulator 66 and communicates between the small area bore 11 and the lubricant reservoir |9a formed in the cup-shaped end l9 of the lower casing section H. An outlet passage 63 is formed in the lubricant pump casing 40 and communicates between thechamber 65 and the sealin surfaces of the compressor 34 and the bearings of the drive shaft 25. The small area piston 19 is slidably arranged in the small area bore 11 to open and to close the lubricant diverting passage 82, the small area piston 19 being biased to close the lubricant diverting passage 62 -by a small spring 84 acting on the plunger".

When the refrigerating machine is started lubricant is discharged from the lubricant pump 35 through the high pressure discharge port 59 andthe valve 61 into the chamber 65 in the lubricant pressure regulator 66. The small area piston 19 being biased to close the lubricant diverting passage 82 allows the pressure in the chamber to become quickly built up to set the lubricant pressure regulator into operation. Under normal operatlon of the machine the lubricant discharged into the chamber 65 is under a pressure higher in onedirection, while the large area piston 18 is subjected to the pressure of the compressed refrigerant in the high pressure refrigerant circuit of the machine and tends to slide the plunger 89 in the opposite direction, The degree of opening of the lubricant diverting passage 82 being controlled by the sliding movement. of the small area piston 19 of the plunger 80 is thus regulated in accordance withthe difierence in pressures of the lubricant in the chamber 65 and the compressed refrigerant in the high pressure refrigerant circuit of the machine. As the degree of opening 0! the lubricant diverting passage 82 establishes the pressure of the lubricant in the chamber 65, the pressure of lubricant in the chamber is regulated in accordance with the pressure of the compressed refrigerant in the high pressure refrig- Brant circuit of the machine. In view of the fact chine, and as these areas are fixed a substantially constant ratio greater than unity between the pressure of the lubricant in the chamber 65 and the pressure of the compressed refrigerant in the .high pressure refrigerant circuit of the machine will be maintained.

During the operation of the machine lubricant under relatively high pressure is supplied from the chamber 65 in the lubricant pressure regulator 66 to the annular recess 50 formed in the drive shaft 25 below the compressor rotor 43 through the outlet passage 83 and a passage 85 formed in the casing 46 of the lubricant pump 35. Also, lubricant under relatively high pressure is supplied from the chamber 65 in the lubricant pressure regulator 66 to the annular recess 49 formed in the drive shaft 25 above the compressor rotor 43 through the outlet passage 83, a vertically disposed passage 86 formed'in the compressor block.

36, an arcuately disposed passage 81 formed in the upper end of the compressor body 36 and a Passage 88 formed in the supporting frame Ill. The body of lubricant retained in the recess 49 forms a seal between adjacent surfaces of the rotor 43 and the supporting frame ill to prevent the escape of compressed refrigerant from the upper end of the compression chamber 42, and the body of lubricant retained in the recess informs a seal between adjacent surfaces of the rotor 43 and the casing 40 of the lubricant pump to prevent the escape of compressed refrigerant from the lower end of the compression chamber 42. Lubricant also flows from the recesses 49 and'ill along the drive shaft 25 into the bearings 24a and a, respectively, in which the drive shaft is journalled to lubricate these bearings.

As best shown in Figs. 2 and 5, a shallow radially disposed depression 88 is formed in the upper end of the rotor 48 on each side of each of the blades 48. A small passage 88 is formed in the lower surface of the supporting frame l0 adjacent the cylindrical wall of the bore 42 and communicating with the passage 88 formed in the supporting frame I! in order to supply lubricant under relatively high pressure from the lubricant pressure regulator 88 to the depressions 89 formed in the upper end of the rotor 43. The lubricant supplied these depressions 88 further seals the upper ends of the rotor 43 and the blades 48 against leakage of compressed refrigerant. In a similar manner a small. passage Si is formed in the upper end of the lubricant pump casing 4ll adjacent the cylindrical wall of the bore 42 and communicating with the passage 88 formed in the casing 48 inordef to supply lubricant under relatively high pressure from the lubrlcantpressure regulator 48 to like depressions formed in the lower end of the rotor 43-: The lubricant supplied these depressions further seals the lower ends of the rotor 42 and the blades 48 against leakage of compressed refrigerant.

Lubricant discharged under relatively low pressure from the lubricant pump 38 into the chamber 82 flows through a passage 82 formed in the lubricant pump casing 48 into a circulating passage or conduit 83 forming the compressor block 88 and extending thereabout in heat exchange relation therewith. The circulating passage 88 is of serpentine configuration and extends from, a position adjacent the lower flange 38, up and down through the blocka number of times, and thereabout to a position adjacent the upper flange 8'l. The lubricant flows through the circulating passage 88 into a passage 94 formed in the supporting frame ill which is connected by a conduit 85 to a lubricant cooler 86 arranged exteriorly of the outlet conduit 53 to a passage 81' formed in the; supporting frame iii.

The compressed refrigerant is conducted through the passage 91 to the exterior of the enclosing casing by a conduit 88 to a lubricant separating device 99. The

com creased refrigerant passes from the upper port on of the lubricant separating device 98 through a conduit I into a forced air cooled re frigerant condenser i0! where it is liquefied and deliiiered to a flow controlling float valve I82. Theliqueflcd refrigerant passes from the float valve I82 into an evaporator i831 wherein the liquidrefrlgerant is vaporized by the absorption of heat. The vaporized gaseous v refrigerant is withdrawn from the evaporator I03 through a conduit I04 and flows back into the enclosing casing through a passage i formed in the supporting frame ill. The gaseous refrigerant reenters the compressor 34 through the inlet conduit 5i.

Lubricant is drawn from the lubricant reservoir Isa formed in the cup shaped end of the lower casing section ll through the screen 12 and into the bore 54 of the lubricant pump 35. The lubricant is pumped through the chambers 54 and a portion thereof is discharged through the low pressure discharge port 58 into the chamber 82 formed in the casing 40. The lubricant contained in the chamber 42 passes upwardly through the passage 82 into the circulating passage or conduit 93, formed in the compressor block 88, and thereabout into the passage 44, formed in the supporting frame i8, through the conduit 85 and into the lubricant cooler 88. It will be observed that the flow of the lubricant in the circulating passage 88 is in a direction from the exhaust port 48 towards the intake port 48 as indicated by the arrows in Figs. 1 and 5. Thus,

across the baflle 32 into contact with the winding ii of the stator 28 of the electric motor and across the stator laminations into an outer annular recess i8! formed between the cylindrical body i8 ofthe upper casing section Ii and the flange 24 provided about the supporting frame II. The lubricant flows from the annular recess lll'i through the passage 33 formed in the flange 28 into the recess 21 formed in the supporting frame II. The annular recess 21 constitutes a lubricant reservoir in which the and turns of the winding II of the stator 28 are submerged. The lubricant in the recess 21 then passes through a passage ill formed in the centrally disposed boss 24 and is discharged through a conduit i88 into contact with the muffler 82 and the compressor block 38 from which the lubricant drains back into the lubricant reservoir |8a formed in the casing section II. The lubricant passing from the lubricant cooler 88 cools the stator 28 and the winding ll of the electric motor, the muilier 52 and the block 38 of the compressor.

A portion of the lubricant drawn into the chamber 54 formed in the lubricant pump casing 40 is pumped to a relatively high pressure and is discharged through the high pressure discharge port 69 into the chamber 88 formed in the lubricent -pressure regulator 48. The pressure of the lubricant in the chamber 85 is remllated in accordance with the pressure of the compressed refrigerant in the high pressure refrigerant circuit of the machine, and this lubricant under rela-J tively high pressure passes upwardly through the passage 83 formed in the lubricant pump casing 48. A portion of the lubricant in the passage 82 flows through the passage 85 into the passage 8i and the annular recess 88 to seal the lower ends of the blades 48 and the compression chamber or bore 42 against leakage of compressed refrigerant and to lubricate the lower ends of the rotor 48 and the drive shaft 25. The remainder of the lubricant in the passage 83 flows through the

passages

88 and 81 formed in the compressor block 88 into the passage." formed in the supporting frame III. From the passage 88 the lubricant flows into the passage 90 and the annular recess 48 to seal the upper ends of the blades 48 and the compres- 1 sion chamber or bore 42 against leakage of compressed refrigerant and to lubricate the upper ends of the rotor 43 and the drive shaft 25.

Some of the lubricant supplied the compressor 84 for purposes of. sealing and lubricating the same finds its way into the bore 42 and becomes trapped in the refrigerant compressed therein.

This trapped lubricant is discharged from the compressor through the

conduits

53 and 98 into the lubricant separating device 99 along with the compressed refrigerant. As before mentioned, the compressed refrigerant passes from the lubricant separating device 99 through the conduit Hill to the refrigerant condenser I while the lubricant is separated therefrom and collected in the lower portion of the lubricant separating device.

A float mechanism H0 is arranged within the lubricant separating device 99 and operates a valve III in response to the quantity of lubricant contained in the lower portion of the lubricant separating device. When a predetermined quantity of lubricant has been collected in the lower portion of the lubricant separating device 99,.

the'float mechanism H0 operates the valve HI to an open position and permits a portion of the lubricant to flow from the lower portion of the lubricant separating device through a conduit H2 into the lubricant cooler 96. I

In the lower portion of the lubricant separating device 99 there is provided a conduit H3 which communicates with a passage H4 formed in the supporting frame I ll. This passage 4 is connected by the conduit 8| to the large area bore 16 formed in the body of the lubricant pressure regulator 66, thus subjecting the large area pistonslidably arranged in the large area bore 16 to the pressure of the high pressure refrigerant circuit, as previously explained.

While I have shown a particular embodiment of my invention, I do not desire my invention to be limited to the construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure b Letters Patent of the United States, is: 1. A refrigerating machine including'an enclosing casing, a supporting frame in said enclosing casing forming upper and lower chambers therein, a drive shaft journaled in said frame and extending into said chambers, an electric motor supported by said frame in said upper chamber, said electric motor including a stator provided with a winding and a rotor secured to said. drive shaft, a refrigerant compressor supported by said lower chamber and driven by said drive shaft, a lubricant pump in said lower chamber and driven by said drive shaft, lubricant reservoirs formed in said upper and flower chambers, a conduit extending from said reservoir in said upper chamber into proximity with said compressor, and means including said lubricant pump for circulating lubricant from said lubricant reservoir in said lower chamber in heat exchange relation with the winding of said electric motor into said upper. reservoir, through said conduit, over the surface of said compressor and back into said lubricant reservoir.

2. A refrigerating machine including an enclosing casing, a supporting frame in said enclosing casing forming upper and lower chambers therein, a drive shaft journaled in said frame and extending into said chambers, an electric motor supported by said frame in said upper chamber,

said electric motor including a stator provided with a winding and a rotor secured to said drive shaft, a refrigerant compressor supported by said frame in said lower chamber and driven by said drive shaft, said refrigerant compressor including a casing provided with a compression chamher having intake and exhaust ports. means inincluding a displacement member arranged in said compression chamber for compressing a refrigerant therein, a first circulating conduit formed in said compressor casing and extending thereabout, a lubricant pump in said lower chamber. and driven by said drive shaft, lubricant reservoirs formed in said upper and lower chambers, a second circulating conduit formed in said frame and extending from said reservoir in said upper chamber into proximity with said compressor casing, a lubricant cooler arranged exteriorly of said casing, and means includingsaid lubricant pump for circulating lubricant from said lubricant reservoir in said lower chamber through said first circulating conduit into said lubricant cooler and in heat exchange relation with the winding of said electric motor, through said second circulatory conduit, and thence over the surface of said compressor casing and back into said lubricant reservoir.

3. A refrigerating machine including an enclosing casing, a supporting frame in said enclosing casing forming upper and lower chambers therein, a drive shaft journaled in said frame and extending into said chambers, an electric motor supported by said frame in said upper chamber, said electric motor including a stator provided with a winding and a rotor secured to said drive shaft, a lubricant reservoir carried by said frame and submerging the end turns of the stator winding of said electric motor, a refrigerant compressor supported by said frame in said lower chamber and driven by said drive shaft, saidrefrigerant compressor including a casing provided with a compression chamber having intake and exhaust ports, means including a displacement member arranged in said compression chamber for compressing a refrigerant therein, a lubricant pump in said lower chamber and driven by said drive shaft, a lubricant reservoir formed in said lower chamber, said lubricant pump having an inlet port communicating with said lubricant reservoir formed in said lower chamber and high pressure and low pressure discharge ports, means for supplying lubricant from said high pressure discharge port under relatively high pressure to adjacent surfaces of said compressor casing and said displacement member for sealing said compression chamber against leakage of compressed refrigerant, and means for circulating'lubricant under relatively low pressure from said low pressaid electric motor including a stator providedwith a winding and a rotor secured to said drive shaft, a recess formed in said frame defining a lubricant reservoir and arranged to submerge the end turns of the stator winding of said electric motor, a refrigerant compressor supported by said framein said lower chamber and driven'by said drive shaft, said refrigerant compressor including 7 a casing provided with a compression chamber having intake and exhaust ports, means including a displacement member arranged in said compression chamber for compressing a refrigerant therein, a lubricant pump in said lower chamber said lubricant reservoir formed in said lower chamber and high pressure and low pressure discharge ports, means for supplying lubricant under relatively high pressure from said high pressure discharge port to adjacent surfaces of said compressor casing and said displacement member for sealing said compression chamber against leakage of compressed refrigerant, means for controlling the pressure of the lubricant supplied for sealing said compressor in accordance with the pressure of the compressed refrigerant to maintain the pressure of the supplied lubricant greater than the pressure of the compressed reirigerant, and means for circulating lubricant under relatively low pressure from said low pressure discharge port in contact with said stator of said electric motor into said lubricant reservoir iormed in said frame and thence in contact with said compressor casing and. back into said lubricant 1o reservoir formed in said lower chamber.

E. JOHNBQN.