US2046477A - Refrigerating apparatus - Google Patents

Description

G. R. OHMART REFRIGERATING APPARATUS July 7, 1936.

Filed. Oct. '7, 1932 2 Sheets-Sheet 1.

INVENTOR. Gkavqmv 1P. w/mmer ATTORNEY.

- July 7, 1936.

G. R. OHMAR-T REFRIGERATING APPARATUS Filed Oct. 7, 1932 2 Sheets-Sheet 2 INVENTOR. 1 GRRY67'0/1 P. Unmmer ATTORNEY.

Patented July 7, 1936 REFRIGERATIN G APPARATUS Grayston R. Ohmart, Detroit, Mich assignor to Kelvinator Corporation, Detroit, Mich, a corporation of Michigan Application October 7, 1932, Serial No. 636,631

14 Claims. (01. 74-66) This invention relates to refrigerating apparatus, and more particularly to refrigerating apparatus of the compression type.

It is oneof the objects of this invention to provide a refrigerating system of the type including a compressor, a driving motor, a condenser and a refrigerant evaporator and an im-,

proved arrangement for cooling the condenser which is especially applicable to refrigerating apparatus wherein the motor and the compressor are both entirely enclosed in a fluid-tight. or hermetically sealed casing.

Another object is to provide a'fan which is cated exteriorly of the casing for cooling the condenser and to arrange for transmitting power from the motor within the casing to the fan by an improved mechanical connection without, in'

any way, affecting the fluid-tight qualities for hermetically sealing the casing enclosing the motor and the compressor.

Another object of this invention is to provide an improved power transmitting joint for transmitting power from the interior to the exterior of a hermetically sealed casing with but a neg-' ligible amount of friction and without in any way affecting the hermetical sealing qualities of the casing.

Another object of my invention is to provide intake and discharge chambers for the compressed fluid, which are of sufiicient size so as to even out the periodic suction'and discharge to and from the cylinder so as to provide silencers which enable the operation of the compressor without pulsation hums.

an improved unloader which is arranged to bypass refrigerant from the compression cylinder until the motor'attains a certain speed and which is also arranged to prevent the by-passi'ng of 40 refrigerant fiuid from said cyinder after the motor attains a certain speed. In practicing the invention, a valve is used to close the by-passing and this valve is arranged so that iteffectively closes the by-pass by mechanically operated means, which are assisted by the pressure created within the compression cylinder after the motor attains a predetermined speed'.;-

Other objects and advantages wfll be apparent' from the following description and accompanying drawings, wherein a preferred form of the .present invention is clearly shown.-

In the drawings: Fig. 1 is a view showing a refrigerating system embodying features of my invention, partly illustrated diagrammatically and an enlarged ver- Another object of my invention is to provide tical cross sectional showing of the motor-compressor unit; and

Fig. 2 is a view in cross section, taken along the line 22 of Fig. 1.

In many refrigerating machines heretofore constructed, a separate compressor and a motor for driving the same have been provided with an external drive shaft for connecting the motor to the compressor. Such machines, however, require the provision of a stuffing. box for the compressor shaft to prevent the escape of refrigerant fluid from, or the admission of air into, the

compressor housing. These stufling boxes required considerable attention to maintain a seal which was entirely fluid-tight. As refrigerating machines of the household type have a relatively small volumetric capacity, a slight amount of leakage of refrigerant or infiltration of air will interfere materially with the successful operation of the machine. In addition, it has been found that stufling boxes after they have been used over an appreciable length of time become noisy, which renders the apparatus entirely unsuitable for household use. Refrigerating machines of this character are generally referred to as of the open type.

It has also been proposed to have the compressor and its driving motor located in a single, hermetically sealed casing adapted to contain refrigerant fluid. With such an arrangement, the stuffing box is entirely unnecessary as the entire operating mechanism may be confined within the interior of the casing, whereby complete fluidtightness of the refrigerating system is assured. Refrigerating machines of this character are generally referred to as the enclosed type. With refrigerating machines of the open type, a fan is usually mounted on the motor or compressor shaft for cooling the condenser. However, with machines of the enclosed type, the fan for cooling the condenser must be located on the exterior of the casing and, to drive this far, it has previously been proposed to provide a separate small motor. This necessitated the use of two motors together with starting and control appamotors are provided and the fan motor fails to.

operate, inadequate condensation of the gaseous refrigerant will result and dangerous high pressures will be produced'as longer, the compressor continues to operate.

in any way affecting the hermetical sealing of the enclosing casing. By this arrangement, stuiflng boxes are eliminated and only onemotor is. required.

Referring now to the drawings for a more detailed description of my invention, the numeral 28 designates, in general, a refrigerating system comprising a motor-compressor unit 22, condenser 24, evaporator 26 and a high side float mechanism 21. The motor-compressor unit comprises a fluid-tight or hermetically sealed casing 38, which includes a central cylindrically shaped casing 32 and removable end casting portions or plates 33 and 35. Within the casing 38 there is disposed a motor 38 and compressor 48. The motor and compressor are operatively connected together by means of a drive shaft 42 which is journalled on one end thereof in a bearing 43 carried by end plate 33. The opposite end of the shaft 42 is provided with a reduced portion 45- which is journalled in a bearing 41 carried by removable end plate 35. The motor 38 includes a rotor 58, which is preferably press-fitted on the drive shaft 42, and a stator 52 carried by casting 32. The compressor includes a cylinder body 54, piston 55 which is adapted to be reciprocated in a cylinder 51 by means of connecting rod 58 operatively connected to the piston and an eccentric portion 68 of the drive shaft 42.

In order to provide means for cooling the condenser, a fan 64 has been provided. Preferably,

the fan 64 is operated by power received from motor 38, which drives the compressor 48. In order to accomplish this, I have provided a mechanical connection between the motor 38 and the fan 64 and arranged such connection in such a manner that power is transmitted to the fan without, in any away, affecting the fluid-tight qualities of the hermetically sealed casing.

/ {The improved mechanical drive connection between the motor 38 and fan 84 comprises, in general, wobble shaft means I8. The shaft means 18 comprises, in general, a yoke-shaped member I2 which serves to connect shaft ends 14 and 15. Between the ends of the yoke-shaped member I8 there is disposed a stationary pivot bearing support 11 for supporting the shaft means. Also, between the ends of the yoke-shaped member I2 there is provided a pivot point member III which is rigidly connected to the shaft means I8. This pivot point I9 is adapted to engage one side of the supporting member I! and provides a point contact therebetween. In order to maintain engagement between the pivot point i8 and the supporting member ",1 have provided a second pivot point 88, which is adapted .to engage, by

is carried by means of a laterally extending portion 88 formed integrally with acover plate 82 which isclamped between an end ring 84 and the removable end plate 35 by means of screws 35. The shaft end I4, pivot points I8 and 88 and the yoke-shaped member 12 are enclosed by means of a flexible expansible bellows 81 which is sealed upon one end thereof to flange 98 on the cover plate 82, and the opposite end is sealed to a membe! I88 to which the end I5 of the shaft is screw threaded and preferably soldered so as to provide a fluid-tight joint therebetween.

From the foregoing, it will be apparent that the casing 32 and plates 33 and 35, together with the cover plate 32 and expansible bellows 91, provide a fluid-tight or hermetically sealed casing which entirely encloses the motor and compressor units.

In order to provide a suitable mounting for the fan 84, I have provided a casting I85, which is preferably carried by the end plate 35, to which the casting I 85.is secured by any suitable means. The casting also provides a housing for the flexible bellows and wobble shaft means. The fan 64 is carried by a suitable small shaft I8I which is journalled in a bearing I88 which is preferably press-fltted within the casting I85.- The shaft is provided with an enlarged head portion H8 in which there is provided a recess III for receiving aspherically shaped end H3 of the wobble shaft-means. Within the hollow portion 5 of the reduced portion 48 of the drive shaft, there is disposed a socket member II8 provided with a recess I28 for receiving a spherically shaped end 122 of the wobble shaft. As will be noted in Fig. l, the recesses Ill and I28 are eccentrically disposed with reference to the axis of the drive shaft and fan shaft. By this arrangement, movement of the drive shaft will affect orbital movements of the ends 3 and I22 of the shaft means to effect rotation of the fan 64. By the present arrangement, it will be noted that the pivot point I3 is held in engagement with the support member 11 by means of the pivot point 88 and spring 82. Consequently, any

movement of the wobble shaft will be substantially if not entirely, free from friction, since there is but a point contact between the shaft means and its support.

In order to provide for lubricating moving elements of the compressor and fan driving mechanism, I have provided a well I25 in the end plate 33 for receiving 011 from the lower portion of the casing 32 by means of an oil flinger I21 Oil received in the well flows through passage I28 intoa radial bore I29 in the drive shaft. Oil passes through the bore into-the hollow portion H5 of the reduced end of the shaft 45, whence it passes to the: bearing support and pivot points. In the event a large amount of oil is ac'eumulated within the expansible bellows, it may readily be returned to the interior of the casing through passage I3I. This prevents the accumulation of too large a quantity of oil within the interior of the bellows, which would prevent proper movement of said bellows.

The fan shaft I81 is provided with lubrication .by means of a wick I35 formed of a body of fibrous material disposed within a cavity I36 adjacent the shaft and bearing in casting I85. when the device is assembled, a quantity of oil may be disposed within the casting, which is in open communication with the cavity through passage I38. Thus, the oil within the casting will supply lubricant to the wick, which in turn will, by

capillary action, lubricate the shaft I01 and required for the shaft and bearing, it may be supplied readily by removing plate I40 and inserting through opening MI.

During operation of the apparatus hereinbefore described, the compressor withdraws gaseous refrigerant from the evaporator through a vapor conduit I50, compresses the gaseous refrigerant-and delivers it to the condenser wherein it is liquefied and from which it is delivered to the high side float mechanism. Liquid refrigerant is supplied to the evaporator by means of a liquid supply conduit I52. As shown in Fig. 2, gaseous refrigerant enters the compressor through an intake chamber I54, whence it passes into the cylinder under the control of a reed valve I55. The compressed refrigerant is discharged from the compression cylinder through a discharge-valve mechanism I51, whence it passes into an. outlet or discharge chamber I60 and through conduit I02 to condenser. In the event any oil is returned from the evaporator to the compressor, it will, upon entering the intake chamber, descend into the lower portion thereof and pass through an opening I69, which is in communication with the interior of the casing 30.

As will be noted in the drawings, the intake and discharge chambers are considerably larger than the cross sectional interior area of the intake conduit I50 and discharge conduitl62. By providing a suction chamber of this type, it has been found that it acts as an oil separator and which provides for automatically retm-ning oil to the crankcase. A relatively large suction chamber also acts as a gas surge chamber which I evens out the periodic suction of the cylinder to an even flow of gas through the suction line. By providing a relatively large discharge chamher, it has been found that it acts as a surge chamber to even out the discharge from the cylinder, which is periodic, to even the flow through the discharge conduit. The discharge chamber also acts as a silencer of the discharged gas through the discharge valve.

Preferably, the motor-compressor unit is intermittently operated and in order to control the operation of the motor-compressor unit, any suitable thermostatically controlled switch may be provided which is responsive to changes of temperatures in the compartment to be cooled by evaporator, or responsive to changes in temperature in evaporator. If desired, a suitable low pressure control of the well known type may be provided for controlling the operation of the motor-compressor unit in accordance with iggnges of pressure within the vapor conduit Preferably, the motor is of the split phase type and has a low starting torque. Under these con- ;ditions, it has been found desirable to provide some sort of an unloader to allow the motor to come up to speed before assuming the load of the compressor. Thus, I- have provided an improved unloader I00 which is adapted to hold a alve member I82 away from its seat I03 until the speed of the motor attains a certain value. By this arrangement, gas entering the compression chamber is by-passed through passage I85 into the interior of the casing and no work is accomplished by the compressor until such certain speed is attained by the motor and'the valve member is closed by the unloader actuating mechanism. when the valve member is in the closed position any pressures created within the as to minimize frictionallosses.

compression cylinder tends to maintain or to urge the valve member towards its seat. The unloader actuating mechanism comprises a suitable sliding collar I01 carried by the drive shaft, which is adapted to be moved by means of a 5 finger disposed within a recess I80 of the collar 1 I81. When the motor begins to operate the unloader actuating mechanism does not effect movement of the valve I02 until the speed of said motor attains a certainvalue. When such a speed is attained, a pair of weights I90, which are actuated by centrifugal force against the action of springs I92, tend to move the finger I88 toward the left side view in the drawings to move the collar in that direction. When this takes place, a lever I94 is moved by the action of a spring I96 and this lever, by means of pushrod I91, tends to move the valve member downwardly to close the valve. When the compressor ceases operation, the slidable collar I81 is returned to the position shown in Fig. 1 of the drawings by the action of springs I92, which overcome the action of spring I90 to slide the collar I81 which moves lever I94 and push rod I01 to open valve I82.

From the foregoing, it will be noted that I have provided a refrigerating system of the type including a refrigerant compressor, a motor for driving the compressor, a condenser and a refrigerant evaporator and an improved arrangement for cooling the condenser, which is especially applicable to refrigerating apparatus wherein the motor and the compressor are both entirely enclosed within the fluid-tight or hermetically sealed casing. Also, it will be noted'that I have providedfor a fan located outside of the casing for cooling the condenser by power received from the compressor driving motor without, in any way, effecting the fluid-tight qualitiesof the her; meticaliy sealed casing. In addition, I have profvided for operating the fan in such a manner so Although only a preferred form of the mven-F tion has been illustrated, and that form described indetail, it will be apparent to those skilled in the, 46

art that various modifications maybe made therein without departing from the spirit of the invention or from the scope of the appended, claims.

I claim:

1. A power transmitting Joint comprising a wall, a wobbling shaft associated with said wall and being adapted for transmitting power, a bearing support for the shaft, and anti-friction means associated with the shaft and said hearing support and being arranged for providing a point contact between itself and said bearing support intermediate the ends of said shaft.

2. A power transmitting joint comprising a flexible wall, a wobbling shaft associated with 00 said flexible wall and being arranged for transmitting power, a bearing support for the shaft, and anti-friction means associated with said bearing support and said shaft intermediate the ends of said shaft, said anti-friction means being 65 arranged for providing a pointed contacting engagement between itself and said bearing support which is relatively small with respect to the size of said shaft.

3. A power transmitting joint comprising a 70 wall, a wobbling shaft associated with said wall and being adapted for transmitting-power, and pivoted means for supporting said shaft witha pointed relatively small contacting surface wi respect to the size of said shaft. 15

' 4. A power transmitting joint comprising a wall, a wobbling shaft extending through said wall for transmitting power, a bearing support for the shaft, anti-friction means providing a point contact between said shaft and said bear-- 1 point associated with'the shaft and in engage- -ment with said pivot bearing member.

7. 'A device with which to connect a rotatable element within a hermetically sealed casing with a rotatable element located outside of -the casing comprising a wobble shaft extending through a wall of said casing, a support for the shaft intermediate its ends, and a pivot point operatively associated with said shaft and said support, the ends of said shaft being eccentrically connected to said rotatable elements whereby movement of one of said rotatable elements will eifect orbital movements of the ends of the wobble shaft to transmit rotary motion from one ofsaid rotatable elements to the other.

8. 'A device with which to connect a rotatable element within a hermetically sealed casing with a rotatable element located outside of the casing comprising a wobble shaft extending through a wall of said casing, a support for the shaft intermediate its ends, means connecting the shaft to said support and resilient means including a bellows and a spring urging said first means toward said support.

' 9. A device with which to connect a rotatable element within a hermetically sealed casing with a rotatable element iocatedoutside of the casing comprising a wobble shaft extending through a wall of said casing, a support for the shaft intermediate its ends. an expansible bellows responsive to pressures within the casing forsealing the joint between the shaft and the casing. means connecting the shaft to said support and means including a spring which cooperates with I the action of said bellows for urging said first named means toward said support.

' 10. 'A device with which to-coiinect a rotatable element within a hermetically sealed casing with a rotatable element located outside of the casing comprising a wobble shaft extending through a wall of said casing, said shaft including a yoke- 5 shaped member between the ends thereof, a stationary support for the shaft disposed between the ends of the yoke-shaped member, and a pivot point carried by the shaft in engagement with said support. 1o

11. A device with which to connect a rotatable element within a hermetically sealed casing with arotatable element located outside of the casing comprising a wobble shaftextending through a -wall of said casing. said shaft includ- 1-'5 ing a yoke-shaped member between the ends thereof, a stationary'support for the shaft disposed between the ends of the yoke-shaped memher, a pivot point carried by the shaft in engagement with one side of said support and a thereof. a stationary support for the shaft disposed between the ends of the yoke-shaped member, a pivot point'carried by the shaft in engagement with one side of said support. a second pivot point associated with said shaft and in engagement with the opposite side of said support, and a spring associated with the second pivot point for maintaining engagement between the first named pivot point and said support.

13. A device with which to connect a rotatable element within a hermetically sealed casing with 4 a rotatable element located outside of the casing comprising a wobble shaft extending through a wall of said casing, said shaft including a yoke-shaped member between the ends thereof and a stationary member disposed between the ends of the yoke-shaped member for mp rti s 14. A device with which to connect one rotat able element with another comprising a wobble shaft including a yoke-shaped member intermediate its ends and a stationary member 'disposed between the ends of said yoke-shaped member for supporting said shaft.

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