US2160018A - Refrigerating system - Google Patents

Description

May 30, 1939- w. w. HIGHAM 2,160,018

REFRIGERATING SYSTEM Filed July 26, 1957 5 FJ J M I SNI- I: 1 M I L j l I Q n 3 n l 1| T. av .l.| 9 1 f@ a K l||\. 0 10 YPatented May 30, 19.39

REFRIGERATING SYSTEM William W. Higham, Detroit, Mich., assignor to Universal Cooler Corporation, Detroit, Mich., a corporation of Michigan Application July 26, 1937. Serial No. 155,591

2 Claims.

This invention relates to refrigerating mechanism, and it has to do particularly with a system wherein the refrigerant is used as a cooling agent for the source of power in the form of an 5 electric motor;

The invention is directed particularly to a system which makes use of a so-called sealed compressor unit wherein the compressor mechanism and motor are housed in a sealed unit. A probl0 lem is presented in such a unit of cooling 4the stator of the motor, since, as it is completelyhoused,`diflculties present themselves in dissipating the generated heatand in keeping the heat away from the compressor mechanism.

It has been proposed -to put heat dissipating ns on the external part of the housing surrounding the stator, but Where the housing is made of sheet metal the ns have to be applied in some manner, as for example, by welding,

and this may distort the housing. Such a distortion, of course, is highly undesirable, particularly in a unit of this kind where the motor and compressor mechanism must be accurately lined up and which alignment is either wholly or partially dependent upon the housing. Moreover, the available surface is too small so that fins on the housingy adjacent the stator do not have sufficient surface for adequate cooling unless some outside means such-as means for blowing air over the ns is used', but this is undesirable.

By the present invention a more efilcient cooling action isobtained than by the use of fins. 'I'he heat is transferred from the stator to the refrigerant and then dissipated by a part of the refrigerating mechanism, as for example, by a portion of a condenser. The cooling action, therefore, is obtained largely when the refrigerant is in motion, and this is at the time the electric motor is functioning and generating 40 heat. In this way, the temperature curve of the stator of the motor is considerably leveled out. The refrigerant may be brought into heat exchange relation with the stator in different ways, vand the condenser arrangement for the refrigerant may be varied, all within the' scope of the invention, and some of these variations are illustrated in the accompanying drawing.

Fig. 1 is a somewhat diagrammatic view showing a portion of a refrigerator and illustrating a sealed compressor unit, condenser, and evaporator.

Fig. 2 is a similar view illustrating a modified form of condenser.

Fig. 3 is an enlarged vview partly in section,

illustrating a modified arrangement for associating the refrigerant in heat exchange relation` with the stator of the motor.

` The diagrammatic illustration of the refrigerator includes a base I, an insulated Wall 2 which forms the bottom' of a refrigerated compartment 3. The compressor unit may be located in this shape between the base I and wall 2. One vertical Wall 4 of the refrigerator cabinet is illustrated.

'I'he sealed motor-compressor unit is generally illustrated at 5. As illustrated in Fig. 3 the housing or shell has an upper portion 6 within which the electric motor is housed, the stator of which is illustrated at l. The armature is illustrated at 8 and the motor shaft at 9. In this instance the motor shaft is vertical. Suit-- able compressor mechanism (not shown) is confined in the lower portion Il) of the housing. It is not necessary to go into detail as to the compressor mechanism, as quite a large number of compressors are known to those skilled in the art, it being sulclent to say that the compressor is operated by the shaft 9.

A suitable evaporator or low-side unit is illustrated at II inside the refrigerated compartment. In the form shown the refrigerant is admitted in this evaporator through the means of an expansion valve I2 which may be thermostatically operated by` al feeler leg I3 associated with the outlet tube for the expanded refrigerant. It will be understood, however, that so far as the present invention is concerned, other types of evaporators and refrigerant flow controls thereto may be used.

In the form shown in Fig. 1 a tube for expanded refrigerant extends from the evaporator to the compressor unit for carrying the expanded gases to the compressor unit. This tube is shown at I5. 'I'he compressed refrigerant inthe form of what may be termed "hot gas leaves the compressor unit through the tube line I6, and this extends to the upper section I'l of a condenser. This condenser, as shown, is mounted in any suitable manner along side of and outside the wall 4. The refrigerant condenses in the section I'I and leaves the same at the bottom thereof through a. tube line I8. This may be in the vform of warm liquid, relatively speaking. The tube line I8 extends to the compressor unit and is wrapped around the upper portion of the housing in the form of a coil I 9. The coil is preferably wrapped around a shell immediately covering or adjacent to the stator. Heat generated by the stator is transferred to the liquid refrigerant in the coil. This, of course, raises the temperature of the refrigerantand it passes then through tube line 2@ back to the portion 2| of the condenser. .In this portion 2i therefrigerant is again and further cooled suitable for entrance into the evaporator through the expansion valve. At the bottom of the condenser unit 2l there may be a receiver tank 22 for receiving the condensed refrigerant and extending from this tank is a tube line 23 which leads to the expansion valve. The inlet line 23 and the suction line i5 may advantageously be disposed in heat exchange relation as illustrated. 'Ihis causes a transfer of heat from the suction line to the refrigerant passing to the evaporator, thus minimizing frosting of the suction line, further cooling the liquid refrigerant, and improving the performance of the unit.

v The condenser is generally, in effect, a radiator and may be formed in various ways. The o ne illustrated herein is formed -by tubing fashioned into suitable runs of'coils.

A modified form is illustrated in 2. but in this form the same reference characters are applied to the compressor unit,',evaporator, and

and the tube line 23 connects'the receiver tank to y j the expansion valve.

The refrigerant may be passed inside the housing for the motor-compressor unit, and this is illustrated as a modified form in Fig. 3. 'I'he tube lines i5, it, it and bear the same rference characters. In this form, howeven, a coil Isa immediately surrounds the stator '7 insidetheshell 6. The stator may be shaped to accommodate the coll, thisshape, as illustrated, 'being in the form of a circumferential recess 25. Suitable sealed connections 28 connect the tube lines i8 and 2@ to the coil la, these connections being in the form of couplings which have a sealed relation with the housing so that the housing repassed through the coil to cool andere mains sealed. In this latter form the heat generated by the stator is transferred more .directly to thereirigerant and it does not have to pass through the housing. This minimizes the ilow of heat to the lower portion of the housing wherein the compressor mechanism is located.

Furthermore, this form gives a better externalA appearance and locates the coils lIta in a more eiilcient position.

Thus the stator of the sealed motor is cooled by the refrigerant, and the cooling action is obtained during the running" speeds, or in other words at the time the heat is being generated. In some installations it may be that the condenser will have to be enlarged somewhat to give it the requisite capacity for cooling both the hot the motor-compressor unit with one section `of the condensera conduit connecting the other section of the condenser to the evaporator, and a coil connected in between the two sections of the condenser and disposed adjacent the housing indirectcontact therewith and in close proximity to the stator of the motor for the passage of liqueed refrigerant therethrough to cool the stator.

2. In a refrigeration system, the combination of a motor-compressor unit, a housing in which the unitv is sealed, a condenser, an evaporator, conduits connecting the motor-compressor unit. condenser and evaporator and forming a circuitous path for refrigerant, said'conduit including parts extending through a wall of the housing and sealed thereto, and including a coil inside the housing disposed in heat exchange relation to the stator of the motor, said coil being in the circuitous path at such a point as to receive liquidA refrigerant whereby liquid refrigerant is said motor.

`l f l W. HIGHAM.

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