US2102391A

US2102391A - Refrigerating machine

Info

Publication number: US2102391A
Application number: US16161A
Authority: US
Inventors: Steenstrup Christian
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1934-06-14
Filing date: 1935-04-13
Publication date: 1937-12-14
Anticipated expiration: 1954-12-14

Description

c. STEENSTRUP 2,102,391

REFRIGERATING MACHINE Original Filed June 14, 1934 2 Sheets-Sheet l Dec. 14, 1937,

Inventor-z Christian Steenstru bg WW1/V7 29m/*M His Attorney.

ec, i4, 937, Q STEENSTRUP ZZ REFRIGERATING MACHINE Original Filed June .14, 1934 2 Sheets-Sheet 2 inventor:

H is Attorneg.'

Christi an Steenstrup,

Patented Dec. 14, 1937 UNITED sTATEs PATENT OFFICE 2,102,39i RErmoERnriNc MACHINE Christian Steenstrup, Schenectady, N. Y., assignor to General Electric Company, a corporation of New Yorli 7 Claims.

My invention relates to refrigerating machines, and is a division of my co-pending application Serial No. 730,589, filed June 1li, 1934.

It is an object of my invention to provide a refrigerating machine having a motor and compressor arranged within an insulated casing and having a lubricating system utilized to dissipate heat generated by the motor and compressor extericrly of the insulated casing.

lo Another object of my invention is to provide a refrigerating machine for cooling a cabinet having a motor and compressor casing enclosed wihin the thermal insulation of the cabinet and provided with an improved system for dissipating 75 heat from the machine.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterzze my invention will be pointed out with particularity in the claims annexed to andforming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawings in which Fig. 1 is an elevation view, partly 5 in section, of a household refrigerator, embodying my invention; Fig. 2 is a sectional perspective view cf the. motor and compressor unit of the refrigerating machine4 shown in Fig. 1; and Fig` 3 is a sectional view of the compressor taken on go the line 3-3 of Fig. 2.

Referriugnow to Fig. 1, I have shown a household refrigerator cabinet IIl mounted on legs II and comprising inner and outer metallic walls or shells' I2 and I3 respectively, 'the inner wall I2 being the liner for the refrigerator compartment, f

and the outer wall I3 being provided with a top wall or plate I4 having a dome I4a thereon. The refrigerator is provided witha door affording ac- -cess to the compartment. Between the inner and outer Walls at the top of the cabinet and within the dome I 4a ls arranged a motor and compressor casing I5 supported on channel irons I6 secured across the top of the cabinet, the ends Vof these channels being resiliently attached to the cabinet to minimize the transmission vof vibration tothe cabinet. A motor and compressor unit I1 is arranged within the casing I5 and supplies compressed gaseous refrigerant through a conduit I8 to a condenser I9 which comprises a sinuous conduit arranged between the inner and outer walls I2 and I3 and clamped in Contact with or otherwise secured to the inner surfaces of three sides of the outer wall I2. Gaseous refrigerant in the condenser I9 is cooled and liquefied by the circulation of air about the outer walls of the cabinet. This arrangement of a condenser on the outer walls of a refrigerator cabinet is disclosed and claimed in my Patent No. 1,985,065, granted December 18, 1934, and assigned to the General Electric Company, assignee of my present inven- 5 tion.

The liquid refrigerant flows from the condenser i9 through a conduit 26 to a receiver or float chamber 2i arranged in the insulation between the inner and outer walls of the cabinet. When l@ a predetermined quantity of liquid has collected within the chamber 2l a-oat 22 rises and a quantity of liquid flows through a connection 23 to an evaporator

2li having headers

25 and 26 oonnccted by a vapor conduit 2l. Liquid refrigerant 15 within the evaporator 24 is vaporized upon absorption of heat from the refrigerator compartment and collects within the

headers

25 and 26 above the level of liquid refrigerant therein from whence it is withdrawn through a suction con- 20 nection 29 by the compressor Within the casing I5. The upper end of the suction connection 29 opens into the casing I5 above a body of oil 3U in the rbottom of the casing. All the space within the inner and outer metallic walls of the refrigerator 25 cabinet and surrounding the casing I5, the receiver 2l, and the other parts of the refrigerating machine is filled with heat insulating material. The insulating material in addition to thermally insulating the refrigerator cabinet and the 3o several parts of the refrigerating machine also serves to minimize the transmission to the cabinet walls of any sound produced by the operation of the motor and compressor within the casing l5. 'I'he body of oil 30 within the casing I5 is utl- 35 lized for lubricating the motor and compressor, unloading 'the compressor, and dissipating the heat generated within the motor and compressor, in a manner which will be hereinafter described.

Referring now to Fig. 2, I have lshown a com- 40 pressor casing I5 comprising an upper shell 32 and a lower shell 33 fitted within the upper shell and welded thereto at 34 to provide a gas-tight joint. Within the casing I5 is arranged a motor comprising a stator 35 provided with windings 36 45 and a rotor 3l mounted on a shaft 38 journale'd in a block 39. The stator 35 is secured to the block 39 by a base ring or end shield 40, which is an annular channel covering the lower end of the winding 36 and welded to the block 39 at 50 4I, the stator being secured to the ring by bolts 40a. The stator 35 and the base ring 40 are surrounded by a corrugated baille 42 which frictionally supports the motor and compressor within the casing I5. In assembling the motor within 55 baiile 42 being of such dimensions as to provide a close i'lt and to retain the motor assembly securely in position within the casing l5. The baille 42 provides a plurality of passages between the vstator and the walls of the casing I5. The baille 42 is constructed to be suiiciently yielding to allow wide tolerances in the machining operations on the parts of the unit, the deformation of the baille when the motor is mounted in the shell permitting some variation inthe diameters of the shell 32 and the stator 35. v

A compressor for the refrigerating machine and an oil pump aresecured below the driving motor. In the construction shown a compressor block 43 is Welded or otherwise secured to the block 39 as shown at 44, and below this is secured a bearing block 45 within which is journaled the shaft 38 and below the bearing block 45 is arranged arr oil pump block 46 and a cover plate 41.

The refrigerant compressor comprises a cylindrical bore 48 in the block 43, which is arranged eccentrically with respect to the axis of the shaft 38. Within the bore 48 and formed integrally with the shaft 38 is a cylindrical compressor rotor 49 which is concentric with the shaft 38 and is mounted so as to run in contact with the Walls of the bore 48 as shown at 50. 'Ihe compressor is provided with an intake port I and an exhaust port 52 arranged near the point of contact 50 and on either side thereof. Two blades,53 are radially and slidably mounted diametrically opposite each other within the compressorrotor 49. During the operation of the compressor the rotor 48 is driven by the motor, and these blades slide in and out of the slots 53a so that they run in contact with the walls of the cylindrical ybore 48. Gaseous refrigerant which enters the intake port 5I from the casing I5 is compressed by the blades 53 within the crescent-shaped space formed between the rotor 49 and the walls of the cylindrical bore 48. The leading edges of the blades 53 are slightly rounded as indicated at 53h in order that the pressure of thecompressed gas withinlthe cylinder will provide a small radial component of force tending to. move the blades 53 away from -the cylinder walls. The trailing edges 'of the blades are relieved to reduce friction. The com'- pressed refrigerant is forced out of the exhaust port 52 upon clockwise rotation of the member 49, the compressed refrigerant passing through an outlet check valve 54,.and thence through the conduit I8 to the condenser. The conduit I8 is connected to'a block 54a which is secured to the block 43 by bolts 55, and the outlet check valve 54 is clamped between the block 4 3 and the block 54a. 'Ihe intake port 5I is provided with a connection 5 8 opening into the casing I5 above the body of oil 39 therein and is provided with a screen 51 to prevent particles of foreign matter from entering the compressor chamber.

'usl

An ou mbrmaung system for the motr. and compressor is arranged so that the refrigerant compressor is loaded and unloaded in response to the pressure of the lubricating oil which is built l up as the motor comes up to speed, and a further arrangement is provided so that thepressure of the oil is substantially independent of the viscosity thereof. The oil circulated' is cooled and utilized to dissipate the heat generated by the motor and compressor to prevent overheating of the refrigerating machine.

In the construction 'shown I provide an oil amasei pump including a cylindrical bore 758 in the block ,46 slightly eccentric with respect to the shaft 38, the walls of the bore 58 being in contact with the shaft 38 at one side. Within a diametrical slot in the shaft 38 is mounted a slidable blade 59 which projects on either side of the shaft and has a length almost equal to the diameter of the bore 58, its length being determined by the eccentricity of the shaft and the bore 58. The slight shortening of the blade necessary because of the eccentricity of the Ibore is not sufficient to materially impair the satisfactory operation of the pump. The shaft 38 and the blade 59 have bearing surfaces in contact with the cover plate 41. A plunger 60 mounted in the shaft 38 and pressed against the blade 59 by a spring 6I maintains the blade 59 in contact with the cover plate. `Oil is admitted to the pump chamber through a port 62 passing through the plate 41 and the block 46, a screen 63 being arranged over the entrance to the port on the bottom of the plate 41 to prevent the admission of foreign matter to the pump chamber. y

Oil is discharged from the pump through a port 84 and passes upwardly through a passage 65 in the block 45 and enters a counterbore 56 in the top of the block 45, eccentric with respect to the shaft 38 and the compressor rotor 49. From the counterbore 65 they oil flows into the slots 53a in which the blades 53 are arranged. A

counterbore 51 is provided in the block 39 above the bore 48 to receive the oil discharged from ,l the Aslots 53a. This bore is also eccentric with :respect to the shaft 38 and is arranged in vthe same relation to the shaft 38 as the counterbore 66. When the refrigerating machine is started and'is coming up to speed oil pressure is gradually built up by the oil pump. The oil j and moves the blades 53 into contact with the walls of the bore 48 thereby loading the compressor. The counterbores 68 and 51 serve to lubricate the bearing surfaces of the compressor rotor 49, and also effectively seal the rotor against leakage of compressed refrigerant. It will be noted that, as the rotor 49 turns, the eccentric counterbores will have a wiping action on the end surfaces thereof, and since the counterlbores are filled with oil under pressure, the oil will lubricate the surfaces of .the rotor and will also seal the rotor against leakage of compressed refrigerant. Referring particularly to Fig. 3, the counterbores 68 andv 61 .are arranged so that as the blades 53 move toward the exhaust port 52 the distance between the counterbores .and the periphery of the rotor 49 increases. In this manner increased resistance to leakage of compressed gas is provided as the pressure of the gas is increased. When the motor is stopped the oil pressure decreases and finally when the blades 53 pass the point 58 and are pressed toward the center of the rotor 49 there is no longer sumcient oil pressure to force them out of the slots toward the walls of 'the bore 48, and the compressor is. then unloaded since the intake and exhaust ports arein communication. The friction of the blades 53 in the slots 53a together with 'the pressure of the compressed gas on the r'elieved leading edges of the blades is sufficient to prevent the blades from being thrown out against the walls of the bore 48 centrifugally 75 with sumoient force to compress gas in the cylinder at speeds below that at which itis desired to unload the compressor.

The viscosity of the lubricating oil may change due to changes in temperature and, for this reason, a change in the pressure developed by the oil in the lubricating system may result from a change in the temperature of the oil. ln order to maintain the pressure substantially constant regardless of changes in the viscosity of the oil, l provide a sharp-edged oriice 88 formed in a cup-shaped insert 69 which is secured to the block 33 and communicated with the upper counterbore [S'l through passages F0 and lll. The passages through which the oil flows before reaching the orifice are made of a sullciently large cross-section to avoid any substantial resistance to the flow of oil. The resistance to the flow of oil necessary for the building up or the desired pressure is supplied by the orifice. Flow of fluid through a sharp-edged orifice is independent of the viscosity of the fluid and hence the pressure of the oil between the pump, which supplies the oil at constant volume, and the orice will not change with varying viscosity of the oil. The provision of a sharp-edged orifice through which oil ows in an oil operated compressor unloader in order to minimize the effect of changes in viscosity of the oil upon the operation of the unloader is not my invention, but is the invention of Harley H. Bixler and is described and claimed in his copending application, Serial No. 1,337, led January l1, 1935, and assigned to the General Electric Company, the

` assignee of my present invention.

Since the oil is under pressure when it passes through the orice any refrigerant which is entrained therein will tend to vaporize on passing through the orifice. In order to prevent the transmission of pulsations from the oil pump, l provide a surge chamber l2 on the discharge side of the orifice 68 which collects a portion of the.

vaporized refrigerant. Refrigerant carried by the oil will be vaporized on passing through the orifice and a body of vapor will collect in this chamber and provide a cushioning effect which will damp out pulsations produced by the oil pump.

The oil discharged from the orifice 68 passes into a conduit 3| the major portion thereof being a sinuous coil in contact with the inner surface of the outer metallic wall i3 of the refrigerator cabinet, so that the wall t3 is utilized as a heat dissipating surface to cool the oil. The oil thus cooled then enters the casing I5 through a connection 13 from which it is discharged into a depression 'i4 in the top of a `bell-shaped shell or hood l5 spaced from the casing i5, and secured on the stator 35. The shell l5 is tted on the upper end of the stator and encloses the upper end of the motor. Oil fills the depression 14 and flows uniformly from the rim of the depression and over the entire surface of the shell T5 absorbing heat therefrom. It then nows downwardly between the casing and the laminations of the stator through the corrugations of the baille 42 and cools the motor and the sides of the casing I5 before returning to the bottom of the casing. The space below the shell 1.5 and around the upper end of the motor is lled with refrigerant vapor which absorbs heat from the motor and is cooled as it is circulated over the under surface of the shell 'I5 by a fan 31a attached to the rotor 31. In this manner the top of the motor is cooled by the oil flowing over the shell l5.

in the operation of the refrigerating machine, which I have described, when the motor is started the oil pump blade 59 will rotate in the cylindrical bore 58 and pump oil from the bottom of the casing l5 and discharge it through the passages @d and 65 to the counterbore 66 and into the slots 53a filling the counterbore 6l and finally the passages lll and ll. When the oil has iilled these several passages it will be discharged through'the orifice 't8 and pressure will be built up between the orifice and the pump. When the motor attains approximately full speed the oil pressure will become sufficient to force the blades 53 radially outward, so that they run in contact with the walls of the bore Q8, and gaseous refrigerant will be drawn from the casing l5 through the screen Sill to the inlet port 5| of the compressor. The refrigerant will be compressedby the rotating blades 53 and discharged through the port 52 and the valve ,54. The refrigerant compressed is .discharged directly into the conduit i8 and flows to the condenser i9 where it is cooled and liquefied, the outer wall of the cabinet being utilzed as a heat disslpating surface over which air circulates by natural draft. Liquid refrigerant then passes upwardly through the conduit .2li and enters the float chamber or receiver 2| from which it is discharged in predetermined quantities and enters the evaporator Q4. Liquid refrigerant within the evaporator 24 is vaporized upon absorption of heat from the refrigerator compartment and collects in the headers 25 and 2S and finally returns through the conduit 29 to the casing l5. The direction of flow of the refrigerant as described is indicated by the solid arrows in the drawings. The oil which is discharged through the orifice 68 enters the surge chamber l2 where any gas therein collects to form a cushioning chamber or pulsation damper. The oil flows into the conduit 3| and-is cooled as it passes through the coils of the conduit 3| which are in contact with the outer wall i3 of the refrigerator cabinet, the wall i3 being cooled by natural draft. rlhe cooled oil is then discharged through the connection i3 and flows into the depression im uniformly over the entire surface of the shell 'l5 and through the corrugations of the baille 42. AIn this manner heat generated by the motor is absorbed by the oil before it returns to the bottom of the casing I5 from which it is again circulated by the oil pump. The direction of flow of the oil is indicated by the dotted arrows in the drawings. y

While I have shown a particular embodiment of my invention in connection with a household refrigerating machine, other applications will readily be apparent to those skilled in the art, and do not, therefore, desire my invention to be limited to the specific embodiment 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 by Letters Patent of the United States is:

1. A refrigerating machine comprising a closed casing and including an electric driving motor, means in said casing for producing circulation of refrigerant, a cabinet for said machine including a metal outer shell and an inner liner spaced therefrom and insulation filling the space therebetween, said inner liner forming a compartment having a door opening affording access thereto, said casing being imbedded in the insulation between the top wall of said metal outer shell an? the top wall of said inner liner, and means i cluding said refrigerant circulating means for cooling said compartment. l

2. A refrigerating machine comprising a closed casing having a compressor and an electric Vdriving motor vtherefor arranged therein, av cabinet for said machine including a metal outer shell and an inner liner spaced therefrom and insulation filling the space therebetween, said-inner liner forming a compartment having a door opening affording access thereto, said casing being imbedded in the insulation between the top wall of said metal outer shell and the top wall of said inner liner, and means including said compressor for cooling said compartment.

3. A refrigerating machine comprising a closed casing having a compressor and an electric driving motor therefor arranged therein, a cabinet for said machine including a. metal outer shell and an inner liner spaced therefrom and insula-` tion filling the space therebetween, said inner liner forming a compartment having a door opening affording access thereto, the top wall of said metal outer shell having a dome extending upwardly therefrom, said casing being arranged in. said dome' and imbedded in the insulation be? tween said metal outer shell and said inner liner,

and means including said compressor for cooling said compartment. l l

4. A refrigerating machine comprising a closed casing having a compressor therein, a cabinet forv said machine including a metal outer shell and an inner liner spaced therefrom and insulation filling the space therebetween, said inner liner forming a compartment having a door opening aiording access thereto, said casing being imbedded in the insulation between the top wall of said metal outer 'shell and the top wall of said inner liner, a. condenser carried by said metal outer shell so as to utilize the surface thereof to dissipate heat from said condenser, and means including said compressor and said condenser for cooling said compartment.

5. A refrigerating machine comprising a closed casing having av compressor therein, a cabinet for said machine including a metal outer shell and an inner liner spaced therefrom and insulation filling the space therebetween, said inner liner forming a compartment `having a door opening affording access thereto, said casing being ,w imbedded in the insulation between the top wall of said metal outer shell and the top wall of said inner liner, a condenser carried by said metal outer shell so as to utilize the surface thereof to dissipate heat from said condenser, means for lubricating said compressor and for circulating lubricant from said casing in heat exchange relation with said metal outer shell for dissipating heat from said casing, and means including said compressor and said condenser for cooling said compartment.

6. A refrigerating machine including a motor and compressor driven thereby, a closed casing for said motor and said compressor, a cabinet for said machine includinga metal outer shell and an inner liner spaced therefrom and insulation filling the space therebetween, said inner liner forming a compartment having a door opening affording access thereto, said casing being imbedded in the insulation ,between the top wall of said metal outer shell and the top wall of said inner liner, means circulating lubricant for lubricating said motor and said compressor, means including a conduit communicating with said lubricating means and arranged in contact-with Said metal outer shell for cooling the lubricant circulated by said lubricating means, and means including said compressor for cooling said compartment.

7. A refrigerating machine including a motor and a compressor driven thereby, a closedcasing for said motor and said compressor, a cabinet for said machine including a metal outer shell and an inner liner spaced therefrom an'd insulation iilling the space therebetween, said inner liner forming a. compartment having a door opening affording access thereto', said casing being imbedded in the insulation between the top wall of said metal outer shell and the top wall of said inner liner, means circulating lubricant for lubricating said motor and said compressor, means including a conduit communicating with said lubricating means and arranged in contact with said metal outer shell for cooling the lubricant circulated by said lubricating means, a condenser communicating with said compressor and arranged between the insulation and the inner surface of said metal outer shell in contact with the latter, and means including said compressor and ,said condenser for cooling said compartment.

CHRISTIAN STEENSTRUP.