US2102390A - Refrigerating machine - Google Patents

Description

Dec. 14, 1937,

C. STEENSTRUP REFRIGERATING MACHINE Filed June 14, 1934 2 Sheets-Sheet l Christian Steehsdclp i @MM by yllwttofheg.

Dec. M, 93?. c; STEENSTRUP REFRIGERATING MACHINE Filed June 14, 1954 Sheets-Sheet 2 Patented Dec. 14, 1937 UNITED STATES PATENT OFFICE REFRIGERATING MACHINE Christian Steenstrup, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York My invention relates to refrigerating machines. It is an object of my invention to provide a refrigerating machine yhaving a motor and compressor arranged Within a casing and having a lubricating system utilized to dissipate heat generated by the motor and compressor.

Another object of my invention is to provide an improved arrangement for utilizing lubricant contained in a compressor for controlling the loading and unloading thereof.

Another object of my invention is to provide a rotary compressor having an improved arrangement for sealing the compressor and for lubricating the same. Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part lof 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 of a household refrigerator cabinet partly in section and including a refrigerating machine embodying my invention; Fig. 2 is a sectional perspective view of the motor and compressor unit of the refrigerating machine shown in Fig. 1, and Fig. 3 is a sectional view of the compressor taken on the line 3--3 of Fig. 2.

Referring now to Fig. 1, I have shown a household refrigerator cabinet |0 mounted on legs I I and comprising inner and outer metallic walls or shells I2 and I3.` respectively, the inner Wall I2 being the liner for the refrigerator compartment, and the outer wall I3 being provided with a top wall or plate I4 having a dome I4a thereon. Between the inner and outer walls at the top of the cabinet and within the dcme I4a is arranged a motor and compressor casing I5 supported on channel irons I6 secured across the top of the cabinet, the ends of these channels being resiliently attached to the cabinet to minimize the transmission of vibration to the 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 I3. 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 th'e General Electric Company, assignee of my present invention.

The liquid refrigerant iiows from the condenser I9 through a conduit 20 to a receiver or float chamber 2l arranged in the insulation between the inner and outer walls of the cabinet. When a predetermined quantity of liquid has collected within the chamber 2| a iioat 22 rises and a quantity of liquid flows through a connection 23 to an evaporator 24 having headers 25 and 26 connected by a vapor conduit 21. Liquid refrigerant 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 connection 29 by the compressor within the casing I5. The upper end of the suction connection 29 opens into the casing I5 abovea body of oil 30 in the bottom of the casing. All the space within the inner and outer metallic walls of the refrigerator cabinet and surrounding the casing I5, the receiver 2i, 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 several parts of the refrlgerating 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. The body of oil 30 within the casing I5 is utilized 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.

This arrangement of a refrigerating machine in a cabinet having a compartment to be cooled is described and claimed in my co-pending application, Serial No. 16,161, filed April 13, 1935, which is a division of the present application.

Referring now to Fig. 2, I have shown a compressor 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 and a rotor 3lv mounted on a shaft 39-ur naled in a block 39. The ,stator 35 is secured to the block 39 by a base ring or end shield 4B, which-is an annular channel covering the lower end of the winding 35 and welded to the block 39 at 4I, the stator being secured to the ring by bolts 48a. The stator 35 and the base ring 48 are surrounded by a corrugated baille 42 which frictionally` supports the motor and compressor within the casing I5. In assembling the motor within the casing I5 the baille 42 is placed around the stator 35 and the base ring 40 and the assembly is forced into the upper shell 32, the corrugated baille 42 being of such dimensions as to provide a close fit and to retain the motor assembly securely in position within the casing I5. The baffle 42 provides a plurality of passages between the stator and the walls of the casing i5. 'Ihe bale 42 is constructed to be suiiiciently yielding to allow wide tolerances in the machining operations on the part-s of the unit, the deformation of the baille. when the motor is mounted in the shell permitting some variation in the diameters of the shell 32 and the stator 35.

A compressor for the refrigerating machine and an oil pump are secured 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 an 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 sh-aft 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. The compressor is provided with an intake port 5| and an exhaust port 52 arranged near the point of contact 58 and on either side thereof. Two blades 53 are radially and slidably mounted diametrically opposite each other within the compressor rotor 49. During the operation of the compressor the rotor 49 is driven by the motor, and these blades slide in and out of theslots 53a so that they run in contact with the walls of the cylindrical bore 48 when the rotor 49 is rotating at its normal running speed. Gaseous vrefrigerant 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. 'I'he leading edges of the blades 53 are slightly rounded as indicated at 53h in order that the pressure of the compressed gas within the 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 compressed refrigerant is forced out of the ex` haust port 52 upon clockwise rotation of the member 49, the compressed refrigerant passing through an outletl check valve 54, and. thence through the conduit I 8-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 43 and the block 54a. Theintake port 5I is provided with a connection 55 opening into the casing I5 above the body of oil 30 therein and is provided with a screen 51 to prevent particles of foreign matter from entering the compressor chamber.

An Aoil lubricating system' for the motor and compressor is arranged so that the Urefrigerant compressor is loaded and unloaded in response to the pressure of the lubricating oil which is built up as the motor cornes up to speed, and a further arrangement is provided so that the pressure of the oil is substannauy independent of the viscosity thereof. The oil circulated is cooled and utilized to dissipatethe heat generated by the motor and compressor to prevent overheating of the refrigerating machine.

In the construction shown I provide an oil pump including a cylindrical bore 58 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 necessitated by the eccentricity cf the bore is not suiiicient 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 4l. 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 47 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.

Oil is discharged from the pump through a port 64 and passes upwardly through a passage 65 y in the block 45 and enters a counterbore 66 in the top of the block 45, eccentric with respect to the shaft 38 and the compressor rotor 49. From the counterbore 66 the oil flows into the lslots 53a in which the blades 53 are arranged. A counterbore 61 is provided in the block 39 above the bore 48 to receive the oil discharged from the slots 53a.

This bore is also eccentric with respect to the shaft 38 and is arranged in the same relation to the shaft 38 as the counter-bore 56. When the refrigerating machine is started and is coming up to speed oil pressure is gradually built up by the oil pump. The oil flows into the slots 53a and when sufficient pressure has been developed it overcomes the friction between the blades 53 and the slots 53a of the bore and also the radial' component of pressure acting on the leading edges of the blades and moves the blades 53 into contact with the walls of the bore 48 thereby loading the compressor. The counterbores and 6l 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 of the rotor 49 and the side edges of the blades 53, and since the counterbores are filled with oil under pressure, the oil will lubricate the surfaces of the rotor and will also seal the rotor and the blades against leak'age of compressed refrigerant. Referring particularly to Fig. 3, the counterbores G6 and 61 are arranged so that as the blades 53 move toward the exhaust port\52 the distancebetween the counterbores and the periphery of the rotor 49 increases. In this manner increased resistanceto leakage of ycompressed gas is provided as the pressure of the gas is increased'. When the motor is stopped the oil presiii) in communication. The friction of the blades 53 in the slots 53a together with the pressure of the compressed gas on the relieved leading edges of the blades is sufficient to prevent the blades from being thrown out against the walls of the bore 48 centrifugally with sufficient force to compress gas in the cylinder at speeds below that at which it is desired to unload the compressor.

The viscosity of the lubricating oil may change due to changes in temperature and, for this reason, a change inthe pressure developed by the oil in the lubricating system may result from a change in the temperature of the oil. In order to maintain the pressure substantially constant regardless of changes in the viscosity of the oil, a sharp-edged orifice 68 is formed in a cupshaped insert 69 which is secured to the block 43 and communicates with the upper counterbore 61 through passages I0 and 1I. 'Ihe passages through which the oil flows before reaching the orifice are made of a sufficiently 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 of the desired pressure is supplied by the orifice. Flow of fluid through a sharp-edged orice 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 orifice will not change with varying viscosity of the oil. The provision of a sharp-edged orifice in a fiuid operated unloading arrangement for a refrigerant compressor in order to minimize changes in the quantity of fluid owing through the system due to changes in viscosity of the fluid is not my invention but is the invention of Harley H. Bixler and is described and claimed in his co-pending application, Serial No. 1,337, filed January 11, i935, and assigned to the General Electric Company, the assignee of my present invention.

Since the oil is under pressure when it passes through the orifice 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, I provide a surge chamber 'I2 on the discharge side of the orifice G8 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.

Theoil discharged from the orifice 68 passes into a conduit 3l 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 I3 is utilized as a heat dissipating surface to cool the oil. The oil thus cooled then enters the casing I5 through a connection 'I3 from which it is discharged into a depression 'N in the top of a bell-shaped shell or hood I5 spaced from the casing I5, and secured on the stator 35. The shell 'I5 is fitted on the upper end of the stator and encloses theA upper end of the motor. Oil fills'the depression It and flows uniformly from the rim of the del pression and over the entire surface of the shell' l5 absorbing heat therefrom. It then iiows downwardly between the casing and the laminations of the stator 35 through the corrugations of the baie 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 i5 and around the upper end of the motor is filled 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 3l. In this manner the top of the motor is cooled by the oil flowing over the shell 15.

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 I5 and discharge it through the passages 64 and 65 to the counterbore 66 and into the slots 53a filling the counterbore 6l and finally the passages 'I0 and 1I, the counterbores 66 and 61 being in constant communication with the slots 53a and the inner ends of the blades 53 therein. When the oil has filled these several passages it `will be discharged through the orifice B8 and pressure will be built up between the orifice and the pump. When the `motor attains a predetermined speed, preferably approximately full speed, the oil pressure acting upon the inner ends of the blades 53 will become sufficient to force the blades 53 radially outward, so that they run in contact with the Walls of the bore 4B, and gaseous refrigerant will be drawn from the casing I5 through the screen 57 to the inlet port 5I of the compressor. The refrigerant will be compressed by the rotating blades 53 and discharged through the port 52 and the valve 54. The refrigerant compressed is discharged directly into the conduit I B and ows to the condenser I9 where it is cooled and liquefied, the outer Wall of the cabinet being utilized as a heat dissipating surface over which air circulates by natural draft. Liquid refrigerant then passes upwardly through the conduit 20 and enters the float chamber or receiver ZI from which it is discharged in predetermined quantities and enters the evaporator 24. Liquid refrigerant within the evaporator 24 is vaporized upon absorption of heat from the refrigerator compartment and collects in the headers 25 and 25 and finally returns through the conduit 29 to the casing I5. 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 ows into the conduit 3| and is cooled as it passes through the coils of the conduit BI which are in contact with the outer wall i3 of the refrigerator cabinet, the wall IIS being cooled by natural draft, The cooled oil `is then discharged through the connection I3 and flows into the depression M uniformly over the entire surface of the shell 'l5 and through the corrugations of the baffle d2. In 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.

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 I do not, therefore, desire my invention to be limited to the specic embodiment shown and described, and I intend in the appended claims to cover all modifications vwithin 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 including a closed casing, a motor and a compressor in said casing, means including an annular corrugated baiile frictionally engaging said motor and compressor for supporting said motor and said compressor within said casing and for frictionally resisting relative displacement therebetween, a body of lubricant within said casing, means including a pump supplying lubricant to said compressor and said motor for lubricating said compressor and said motor, means for cooling lubricant discharged from said compressor, means including a hood having a closed depression in the top thereof and arranged over said motor for distributing lubricant uniformly aboutl said motor and through the corrugations of said baille to cool said motor, and means for supplying lubricant from said cooling means to said depression in said hood.

2. A refrigerating machine including a closed casing, a motor and a compressor arranged within said casing, and means including an annular sheet having corrugations extending axially of said motor for frictionally retaining said motor in position within said casing and for irictionally resisting axial displacement between said motor and said casing, said annular sheet extending about said motor and said-corrugations in said sheet being distorted by compression between said casing and said motor.

3. A refrigerating machine including a closed y casing, a motor and a compressorwithin said casing, and means including'an annular corrugated sheet arranged between said motor and said casing for frictionallysecuring said motor within said casing and for frictionally resisting axial displacement between said motor and said casing, said annular sheet extending about said motor and saidv corrugations in said sheet being distorted by compression between said casing and said motor.

' 4. A refrigerating machine including a closed casing, a lmotor and a compressor arranged within said casing, an inverted shell having a closed depression in the top thereof secured above said motor, means including a corrugated baillesheet for providing passages for cooling uid between said' motor and said casing, and means producing a flow of cooling uid into the depression in said shell over said shell and through the passages formed by said corrugated sheet for cooling said motor.

5. A refrigerating machine including a closed casing, a compressor having intake and ,exhaust ports and arranged in said casing, saifd compressor including a block having a cylindrical bore therein, a rotor eccentrically mounted within the bore in said block and having longitudinal slots formed therein, radially movable blades mounted in said slots, cylinder heads at the ends' of the bore in said block, said cylinder heads having counterbores therein, the counterbores in said heads surrounding the axis of said rotor and being arranged farther from the periphery of said rotor adjacent the exhaust port of said compressor than from the periphery of said rofor adjacent the intake port thereof, said counterbores constantly communicating with the -inner ends of said blades in all positions of said rotor and extending across a substantial portion of the side edges oi said blades, and means for supplying lubricant to'said counterbores vto seal said rotor against leakage of compressed uid.

d., A reirigerating machine including a closed casing, a compressor within said casing, said compressor including a block with a cylindrical bore therein, a rotor mounted eccentrically within the bore in said block and having longitudinal slots formed therein, radially movable blades mounted in said slots, cylinder heads at the ends of the bore in said block, said cylinder heads having cylindrical counterbores therein eccentric with respect to said rotor, said counterbores constantly communicating with the inner ends of said blades in all positions of said rotor and extending across a substantial portion of the side edges of said blades, and means including a body of oil Within said casing and supplying lubricant under pressure to the counterbores in said cylinder heads for lubricating said rotor and for sealing said rotoi` and said blades against leakage of compressed i'luid.

7. A fluid compressor including a block having a cylindrical bore therein and intake and exhaust ports communicating with the bore, a rotor eccentrically arranged within the bore in said block and having longitudinal slots formed therein, radially movable blades mounted in said slots, cylinder heads at the ends of said bore, said heads having counterbores therein adjacent vsaid rotor and arranged about the axis thereof,

the counterbores in said heads being farther from the periphery of said rotor adjacent the exhaust port than from the periphery of said rotor adjacent the intake port in said block, said counterbores` constantly communicating with the inner ends of said blades in all positions of said rotor and extending across a substantial portion of the side edges of said blades, and means supplying lubricant under pressure to said counterbores for lubricating said rotor and for sealing said rotor and 'said blades against leakage of compressed iiuid.

8. A iiuid compressor including a stationary member having a cylindrical bore therein, a

rotor member arranged Within said bore and having longitudinal slots formed therein, radially movable blades mounted in said slots, one of said members having a counterbore eccentric with respect to the axis of rotation of said rotor member, said counterbore constantly communicating with the inner ends of said blades in all positions of said rotor member and extending across a substantial portion of the side edges oi' said blades, and means supplying lubricant to the counterbore in said one member for lubri-- y ing a cylindrical bore therein, cylinder heads at the ends of the bore in'said block, a rotor arranged eccentrically within said bore and having lcngitudinal slots formed therein, radially movable blades mounted in said slots, said cylinder heads having counterbores therein eccentric with respect to said rotor, said counterbores constantly communicating with the inner ends of said blades in all positions of said rotor and extending across a substantial portion of the side edges of said blades, and means supplying lubricant to the counterbores in said heads for lubricating said rotor and for sealing said rotor and said blades against leakage of compressed fluid.

l0. A fluid compressor including a block having a cylindrical bore therein, cylinder heads at the ends of said bore, a rotor arrangedeccenaioasoo mounted in said slots in said rotor, means supplying lubricant under pressure for forcing said blades outwardly against said block to load said compressor, and means including counterbores in said cylinder heads eccentric with respect to the axis of rotation of said rotor for lubricating said rotor and for sealing said rotor and said blades against leakage of compressed fluid, said counterbores extending across a substantial portion of the ends of said blades and communieating With'the ends of said longitudinal slots formed in said rotor.

CHRSTIAN STEENSTRUP.

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