US2357099A - Refrigerating apparatus - Google Patents

Description

Aug. 29, 1944. g s. GAUGLER 2,357,099

REFRIGERATYING APPARATUS Filed Feb. 25, 193 9 2 Sheets-Sheet l ATTORNEYS- R. S. GAUGLER REFRIGERATING APPARATUS Aug. 29, 1944.

2 Sheets-Sheet 2 Filed Feb. 25, 1939 I Patented Aug. 29, 1944 REFRIGERATING APPARATUS Richard S. Gaugler, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a

corporation 'of Delaware Application February 25, 1939, Serial No. 258,519

,13 Claims.

This invention relates to refrigerating apparatus and more particularly to two-temperature household refrigerators incorporating a secondary refrigerant circuit. I

It has been recognized that the ideal construction for a household refrigerator cabinet involves two refrigerating temperatures, one for freezing ice and a higher temperature for cooling foodstuffs in order to maintain a high'humidity in the food compartment. The providing or two refrigerating temperatures makes the refrigerating system more complicated and it ha been proposed to employ a secondary refrigerant circuit for obtaining the higher refrigerant temperature used for cooling the food compartment. A simple secondary refrigerant system does not provide a means for temperature control and it has been proposed to employ a pressure or temperature operated valve for this purpose. The use of refrigerant valves in such a secondary circuit is not desirable in all respects, since the valves are comparatively costly to manufacture and to keep in order. 1

a secondary refrigerant circuit employing inert gas.

It is still another object of my invention to provide a simple means which will trap liquid refrigerant within a portion of the secondary circuit in order to reduce the cooling effect ,and the amount of refrigerant circulated in the secondary circuit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form ofthe present invention is clearly shown.

In the drawings:

Fig. 1 is a vertical sectional view taken through a household refrigerator cabinet 'of a two-temperature two compartment type embodying one form of my invention;

Fig. 2 is a sectional view of the temperature evaporator of the secondary refrigerant circuit. i In one form the secondary refrigerant circuit is provided with an inert gas and a chamber having its volume controlled according to temperatures of the food compartment for varying the pressure of the inert gas inthe secondary circuit in order to change-the evaporating temperature of the secondary circuit. In another form of the invention a temperature controlled liquid trap is provided which reduces or stops the circulation of liquid refrigerant in the secondary circuit by withdrawing a portion of the liquid refrigerant from active circulation. 7

Referring now to the drawings and more particularly to Fig. 1 there is shown a refrigerator cabinet 20 provided with a freezing compartment 22 and a food compartment 24 beneath and insulated from the freezing compartment 22. A primary refrigerant evaporating mean 26 is provided in the freezing compartment 22 and has shelves for supporting ice trays which may contain water to be frozen.- The primary evaporating means 26 forms a portion of a primary refrigerant circuit which includes a sealed motor-compressor unit 28 for withdrawing evaporated refrigerant from the upper portion of the evaporating means 28 through the suction conduit 50. The refrigerant is compressed by the motor-compressor unit 28 and forwarded to a condenser 32 where the compressed refrigerant is liquefied and collected in a receiver 34. From the receiver 34., the liquid refrigerant is forwarded through a liquid supply conduit It to a restrictor 38 which controls the flow of refrigerant into the bottom of the primary evaporating means 26.

The operation of the primary refrigerating system is controlled by a snap acting thermostat switch l0 which is connected to and operated in accordance with the temperature of a thermostat bulb 42 mounted in direct heat exchange relation with the side wall of the primary evaporating means 26. maintain the primary evaporating means at temperatures below freezing in order that ice may be The switch means 40 is so set as to frozen at alltimes. In the conventional refrigerator, the cooling of the food compartment 24 at such a low temperature causes frost to form upon the evaporating means and also causes the dehydration of the air and the maintenance of a low relative humidity within the food compartment.

Therefore, for the refrigerator shown, I have provided a secondary refrigerant circuit including a condenser 44 mounted in heat exchange relation with the side wall of the primary evaporating mean 26 and connected at its lower and up- 4 per ends with the lower and upper ends of a plate type secondary evaporator 43 provided with a header 48 at its lower edge and a header at its upper edge. This evaporator 48 is formed of two closely spaced metal sheets forming a flat rectangular refrigerant container which is held in a slanting position in the top of the food compartment 24.

If adequate heat transfer surfaces were provided upon both the evaporator and the condenser of the secondary refrigerant circuit it is possible that if the circuit were merely charged with a volatile refrigerant that the evaporator 43 might be cooled nearly to the temperature of th primary evaporating means 26. In order to avoid this, the secondary refrigerant circuit is charged with an inert gas as well as a volatile refrigerant in order to raise the condensing pressure and temperature and thereby the evaporating temperature and pressure within the secondary circuit so as to maintain the secondary evaporator 46 at temperatures above freezing. The presence of the inert gas in the secondary refrigerant circuit insures a certain temperature differential between the primary evaporating means 28 and the secondary evaporating means 46.

However, in order to provide a better control of the temperatures in the food compartment 24 I provide a control means including an adjustable chamber 52 of variable volume which is connected to a portion ofthe condenser 44 by a connecting conduit 54. lows 63 within this chamber 52 of variable volume is connected by capillary tubing 56 to a thermostat bulb 58 located in the food compartment 24.

The construction of the chamber 52 of variable volume is better shown in Fig. 2 and includes a cup-shaped castin 68 closed by a cap member 62 upon which is mounted a large bellows G4 and an inner bellows 66. Each of these bellows has its open end anchored to and sealed to the cap member 82. The closed end of the large bellows 64 is provided with a reinforcing plate 63 which is held against the closed end of the inner bellows 66 bya compression type coil spring which'may have its tension adjusted by the knurled adjusting screw I2. The interior of the inner bellows 66 is connected to the capillary tubing 53, heretofore referred to, which in turn connects to the thermostat bulb 58 lodged in the food compartment 24. The bulb 58 is preferably charged with a volatile liquid so that the inner bellows 66 will expand and collapse according to the rise and fall in temperature within the compartment 24. The expansion and col- 1 lapse of the small bellows 66 will expand and collapse the large bellows 64 to change the volume of the space 65 between the large and the inner bellows which space 65 is connected by the tubing 54 to the condenser .44 of the se ondary refrigerant circuit.

An inner control bel-' By changing the volume of the bellows 44 the volume of the inert gas in the condenser of the secondary circuit will be likewise changed so that 'when the bellows 44 is collapsed the volume of the inert gas in the secondary condenser will be increased to increase the temperature diflerential between the primary and secondary evaporators 2i and 44. The collapse of the bellows 34 is accomplished by the'compression coil spring 10 which will collapse both bellows when the temperature and pressure within the thermostat bulb 53 is low. An increase in temperature of the thermostat bulb is will cause an increase in pressure in the inner bellows and will cause an expansion of both bellows thus increasing the volume of the bellow -64 to permit a reduction in the volume of the inert gas to reduce the temperature differential between the primary and secondary evaporators.

The temperature maintained in the food compartment 24 may be adjusted by employing the knurled screw 12 to change the tension of the compression spring 14. Thus if the knurled screw is backed out to releasethe pressure of the spring 13 the temperature within the food compartment will be lowered. It will be seen that this form of secondary refrigerant circuit is provided with an adjustable thermostatic control without any form of valve.

In Fig. 3 there is shown a somewhat different form of two-temperature, two compartment household refrigerator provided with a modified form of secondary refrigerant circuit and control which, however, is generally the same in principle as the form shown in Fig. 1. In Fig. 3 there is shown an inner liner member 323' of a household refrigerator surrounded by insulation and outer walls indicated diagrammatically,

by the dot and dash outline 322. Within the inner liner is a glass plate 324 which divides the interior of the cabinet into an upper low temperature low humidity compartment or region 326 which contains the primary evaporating means 328 and a lower high temperature high humidity compartment or region 330. The glass plate 324 is provided with a rubber sealing gasket 332 at all four edges which extends into sealing engagement with the three walls of the inner liner 320 and the inner face of the door 334. The primary evaporating means 328 is connected to a refrigerant liquefying apparatus, not shown, but which is similar to that shown in Fig. 1. This liquefying apparatus is controlled by a thermostat mounted directly upon the side of the evaporating means 328 in order to control the operation of the liquefying means to maintain the primary evaporating means 323 at freezing temperatures.

In order to cool the lower compartment or region 333, the outer face of the inner liner member 320 is provided with serpentine loops 334 of a secondary refrigerant circuit. These serpentine loops 336 are clamped to the outer face of the inner liner 320 by suitable clamping means and sealing compound may be provided in order to increase the heat transfer between the loops 336 and the adjacent portions of the inner liner member 320. The uppermost serpentine loop is connected to the secondary condenser 333 which is clamped to the bottom of the primary evaporating means 323'. This condensin portion 334 is formed of one or more serpentine loops and a goose-neck type of trap 340 is provided for preventing any liquid condensing in the condensing P rtion 338 from being drained directly into the upper serpentine loop. i

The other end of the condensing portion 338 connects to a section of flexible, tubing designated by the reference character 342 and supported at its ends by the arms of a bracket 344 which is fastened to the rear wall of the inner liner 328. One end of this flexible tubing 342 is of course connected to the condensing portion 338 while the other'end is connected to a downwardly extending conduit portion 348 of the secondary refrigerant circuit which feeds liquid refrigerant to the serpentine coils provided upon the bottom of the inner liner 328. It will be understood that by raising the'middle portion of the flexible conduit 342, liquid refrigerant will be trapped in the condensing portion 338. If the condensing por-' duit 342 is lowered then the refrigerant in the secondary circuit can circulate and refrigerate the lower compartment 338.

This simple means is employed to control the refrigeration provided by the secondary circuit for the lower compartment 338. In order to do this a bellows 348 is provided within a casing 358. The interior of this bellows is provided with a compression type coil spring and the bellows 348 is supported between another compressiontype coil spring 352 and an adjusting screw 354 which is adapted to compress the bellows 348 to change the tension of the compression spring enclosed therein. The bellows 348 is preferably vcharged with volatile liquid and since the case 358 is located within the compartment 338 the pressure within the bellows 348 will correspond to the temperature within the compartment 338.

One end of the bellows 348 is connected by a link 358 to a bell crank lever 358 which operates a rod 368 extending vertically upwardly andconnected at its upper end to the mid-point of the flexible tube 348. By this arrangement, when the bellows 348 expands in response to an increase in temperature in the lower compartment 338, the bell crank lever-358 is pivoted in a clockwise direction about its pivot point to lower the rod 368 and the mid-point of the flexible tubing 342 to permit the liquid to drain from the secondary-condenser 338 and cool the lower compartment 338. compartment 338 falls to a predetermined minimum the bellows 348 will collapse and raise the rod 368 and the mid-point of. the flexible tubing 382 to restrict or prevent the draining of the condensed liquid from the secondary condenser 338 and thus prevent further condensation and circulation of the liquid refrigerant in the secondary circuit for the time being.

By manipulating the adjusting screw 354 so as to increase thetension of the compression spring within the bellows 348,.the lower compartment will be maintained at. a lower temperature; while if the tension of the spring is reduced, the compartment temperature will be raised.

It will be seen that the effective capacity of condensing portion 338 will vary with changes in movement of movable portion 342 because, as liquid refrigerant flows out of condensing portion When the temperature of the- 338'when movable portion 342 is lowered or as liquid refrigerant accumulates in condensing portion 338 by liquefaction when movable portion 342 is raised, the extent of surface effective to liquefy refrigerant in'condensing portion 338 increases or decreases. When the condensing portion 338 has become filled with liquid refrigerant after movable portion 342 has been raised, the effective capacity of condensing portion 338 .is reduced to a minimum. Then, when portion 342 is lowered, liquid refrigerant flows out of condensing portion 338 and the effective capacity of condensing portion 338 to liquefy refrigerant obviously increases progressively until it reaches its maximum when the condensing portion is emptied of liquid refrigerant if movable portion 342 should be fully lowered. After portion 342 is again raised, liquid refrigerant accumulates in condensing portion 338 andthe capacity of the latter to liquefy refrigerant is effectively and progressively diminished until reached when portion 338 becomes filled with liquid refrigerant. Thus I have provided a secondary refrigerant circuit in different forms its minimum is without any valves but with a simple effective temperature control which can be readily adjusted to provide any desired temperature within a reasonable range within the food compartment of a two-temperature household refrigerator.

While the forms of embodiment of the invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A refrigerating apparatus comprising in combination, a primary refrigerating system ineluding. a refrigerant liqu'efying unit and an evaporator connected in closed circuit relation,

said evaporator having metal walls in which the refrigerant is located, a closed secondary circuit containing a volatile liquid enclosed in 7 metal walls and having an evaporating portion, a portion of the metal walls of said primary evaporator being in direct metal-to-metal contact with a. portion of the metal walls of the secondary circuit to form a condensing portion in the secondary circuit, and means for controlling the temperature of the evaporating portion of the secondary circuit, said means consisting of means for elevating a part intermediate the condensing portion and the evaporating portion of said secondary circuit above the plane of the condensing portion thereof whereby said volatile liquid will be trapped in that portion of the metal walls of the secondary circuit which is in contact with the walls of the primary evaporator.

2. A refrigerating apparatus comprising in combination, a primary refrigerating system including a refrigerant liquefying unit and an evaporator connected in closed circuit relation, said evaporator having metal walls in which the refrigerant is located, a closed secondary circuit containing 'a volatile liquid enclosed in metal walls and having an evaporating portion, a portion of the metal walls of said primary evaporator being in direct metal-to-me'ral contact with a portion of the metal walls of the secondary cir- I trapping said volatile ,liquid in that portion of the metal walls of the secondary circuit which is in contact with the walls of the primary evaporator to thereby control the temperature of the evaporating portion of said secondary circuit.

3. A refrigerating apparatus comprising, a closed primary refrigerating system including an evaporator, a closed secondary refrigerating circuit containing a volatile liquid, said secondary circuit including a condensing portion in heat exchange relationship with said primary evaporator and an evaporating portion, and means for controlling the temperature of said evaporating portion of the secondary circuit, said temperature controlling means consisting of means for elevating a part of said secondary circuit above at least a part of the condensing portion thereof to trap volatile liquid in the condensing portion of said secondary circuit.

4, A refrigerating apparatus, comprising, a closed primary refrigerating system including an evaporator, a closed secondary refrigerating circult containing a volatile liquid, said secondary circuit including a condensing portion in heat exchange relationship with said primary evaporator and an evaporating portion, and means for controlling the temperature of said evaporating portion of the secondary circuit, said means consisting of means responsive to the temperature produced by said evaporating portion of said secondary circuit for elevating a part of the secondary circuit above at least a part of the condensing portion thereof to trap volatile liquid in the condensing portion of said secondary circuit.

. 5. A refrigerating apparatus comprising in combination, a cabinet having two food storage compartments provided therein, a closed primary refrigerating system associated with said cabinet and including an evaporator located therein for cooling one of said compartments, a closed secondary refrigerating circuit associated with said cabinet and containing a volatile liquid, said closed secondary circuit including a condensing portion in heat exchange relationship with said primary evaporator and an evaporating portion in heat exchange relationship with the other of said compartments for cooling the same, and means for controlling the temperature of said evaporating portion of said secondary circuit, said means consisting of means for elevating a part of said secondary circuit above at least a part of the condensing portion thereof to trap volatile liquid in the-condensing portion of said secondary circuit.

6. A refrigerating apparatus comprising in combination, a cabinet having two food storage compartments provided therein, a closed primary refrigerating system associated with said cabinet and including an evaporator located therein for cooling one of said compartments, a

' closed secondary refrigerating circuit associated vwith said cabinet and containing a volatile liquid, said closed secondary circuit including a condensing portion in heat exchange relationship with said primary evaporator and an evaporating portion in heat exchange relationship with the other of said compartments for cooling the same, and means for controlling the temperature of said evaporating portion of said secondary circuit, said temperature controlling means consisting of means responsive to the temperature of said other compartment for elevating a part of said secondary circuit above at least a volatile liquid in the condensing portion of said secondary circuit.

'7. A refrigerating apparatus comprising in combination, a cabinet having an upper food storage compartment and a lower food storage compartment provided therein, a closed primary refrigerating system associated with said cabinet and including an evaporator located therein for cooling said upper compartment, a closed secondary refrigerating circuit associated with said cabinet and containing a volatile liquid, said closed secondary circuit including a condensing portion in heat exchange relationship with said primary evaporator and an evaporating portion in heat exchange relationship with said lower compartment for cooling the same, and means for controlling the temperature of said evaporating portion of said secondary circuit, said means consisting of means for elevating a part intermediate the condensing and evaporating portions of said secondary circuit above at least a part of the condensing portion thereof to trap volatile liquid in the condensing portion of said secondary circuit.

8. A refrigerating apparatus comprising in combination, a cabinet having an upper food storage compartment and a lower food storage compartment provided therein, a closed primary refrigerating system associated with said cabinet and including an evaporator located therein for cooling said upper compartment, a closed secondary refrigerating circuit associated with said cabinet and containing a volatile liquid, said closed secondary circuit including a condensing portion in heat exchange relationship with said primary evaporator and an evaporating portion in heat exchange relationship with said lower compartment for cooling the same, and means for controlling the temperature of said evaporating portion of said secondary circuit, said temperature controlling means consisting of means responsive to the temperature of said lower compartment for elevating a part intermediate the condensing and evaporating portions of said secondary circuit above at least a part of the condensing portion thereof to trap volatile liquid in the condensing portion of said secondary circuit.

9. A two-temperature refrigerator comprising a cabinet having a food storage compartment, a primary refrigerating system including an evaporator for cooling one region of. said compartment, a secondary refrigerating system comprising a cooling portion arranged for cooling another region of said compartment and a condensing portion disposed in heat exchange relationship with said evaporator and conduits connecting said portions, said conduits being free of mechanical restrictions to afford fully open communication at all times between said portions of part of the condensing portion thereof to trap the secondary refrigerating system and a portion of one of said systems being movable relative to other portions thereof, and means for moving said movable portion of said one system, said movable portion being so constructed and arranged that movement thereof caused by said means varies the effective capacity of said condensing portion to liquefy refrigerant.

10. A two-temperature refrigerator comprising a'cabinet having a food storage compartment, a primary refrigerating system including an evap-, orator for cooling one region of said compartment, a secondary refrigerating system comprising a cooling portion arranged for cooling another region of said compartment and a condensing portion disposed in heat exchange relationship with said evaporator and conduits connecting said portions, said conduits being free of mechanical restrictions to afford fully open communication at all times between said portions of the secondary refrigerating system and a portion of one of said systems being movable relative to other portions thereof, and means for causing movement of said movable portion of said one system, the portions of said secondary system being so arranged with respect to one another and to said evaporator that said movement varies the extent of surface of said condensing portion effective to liquefy refrigerant.

ii. A two-temperature refrigerator comprising a cabinet having a food storage compartment, a

primary refrigerating system including an evap-' orator for cooling one region of said compartment, a secondary refrigerating system comprising a cooling portion arranged for cooling another region of said compartment and a condensingportion disposed in heat exchange relationship with said evaporator'and conduits connecting said portions, said conduits being free of me-- chanical restrictions to afford fully open communication at all times between said portions of the secondary refrigerating system and a portion of one of said systems being movable rela- I erant liquefying and circulating unit and an evaporator having refrigerated walls for cooling air in one region of said cabinet, means including a thermal element mounted in direct heat exchange relationship with one wall of said evaporator and responsive to the temperature thereof for controlling operation of said unit to normally maintain the evaporatorbetween predetermined temperature limits, a closed secondary refrigerant circuit including a refrigerant evaporating portion for cooling another region of said cabinet and a refrigerant condensing portion, and said refrigerant condensing portion of said second- 7 ary circuit having at least apart thereof located in heat exchange relationship with said one wall of said primary evaporator and with said thermal element.

13. A refrigerating apparatus including a cabinet, a closed primary refrigerating system associated with said cabinet and including a refrigerant liquefying and-circulating unit and an evaporator having at least one'upright and other refrigerated walls for cooling air in the upper region of said cabinet, means including a thermal element mounted in direct heat exchange relationship with said upright wall of said evaporator and responsive to the temperature thereof for controlling operation of said unit to normally maintain the evaporator between predetermined temperature limits, a closed secondary refrigerant circuit including a refrigerant evaporating portion for cooling air in the lower region of said cabinet and a refrigerant condensing portion, and said refrigerant condensing portion of said secondary circuit having at least a part thereof located inheat exchange relationship with said upright wall of said primary evaporator and withl l d thermal element. v

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