US2073123A - Refrigerating apparatus - Google Patents

Description

March 9, 1937. R. M. SMITH REFRIGERATING APPARATUS F i ld Jan. 31, 1935 ATTORNEYS r unw Patented Mar. 9, 1937 PATENT OFFICE v 2,073,123 REFRIGERATING APPARA'rUs Rolf M. Smith, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, at corporation of Delaware Application January 31, 1935, Serial No. 4,212

2 Claims.

This invention relates to refrigerating apparatus and more particularly to domesticelectric refrigerators having means for cooling the interior of a refrigerator as well as means for freezing ice and desserts.

Domestic electric refrigerators have two functions to perform, one function is the preservation of food and the other function is the freezing of ice and desserts. Heretofore it has been necessary to provide an apparatus suiiiciently powerful and sufficiently large to accomplish both of these functions at the same time since while freezing is being performed it is also necessary to maintain the refrigerator at-a sufficiently low temperature to prevent food spoilage. However, this requires a much larger refrigerating apparatus than is required the majority of the time since ice cubes and frozen desserts are only de sired occasionally in most households.

It is an object of my invention to so construct a refrigerating system that the refrigerating load is so distributed that adequate refrigeration is supplied even though the refrigerating apparatus and particularly the compressor may not be 5 large enough to take care ofboth the box cooling and the ice freezing loads at the same time.

It is a further object of my invention to provide a refrigerating system which maintains the proper temperature within the refrigerator cabi- 3 net during ice freezing and yet does not require the compressor to assume this box cooling refrigerating load during ice freezing.

Further objects and advantagesof the present invention will be apparent from the following 5 description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a fragmentary vertical sectional view 0 of a domestic electric refrigerator cabinet together with a refrigerating system embodying my invention;

Fig. 2 is a sectional view along the line 2-2 of Fig. l, and a Fig. 3 is an enlarged sectional view of a portion of thecooling unit shown in Fig. 1 which is taken along the line 33 of Fig. 2.

Referring now more particularly to Fig. 1,

there is shown a refrigerator cabinet generally 0 designated by the reference character 28 having insulated walls 22 enclosing a food compartment Within the food compartment 24; there is provided a cooling unit generally designated by the reference character 25. This cooling unit 2t forms the evaporator of the reirigerating sys= tem which comprises a compressor 28 for compressing the refrigerant and forwarding the compressed refrigerant to a condenser 30 where the compressed refrigerant is liquefied and collected in a receiver 32. From the receiver 32 the liquid refrigerant is-forwarded through a supply conduit v34 to a heat interchanger 36 and from the heat interchanger 36 through a supply conduit 38 to a' pressure reducing device 40 which is disclosed as a capillary type of restrictor. The liquid refrigerant after passing through the pressure reducing device 40 evaporates within the cooling unit 26 in a manner to be hereafterexplained and is returned through the compressor through the return conduit 42, the heat interchanger 36 and the return conduit 44. In the heat interchanger 36 the cold evaporated refrigerant from the cooling unit removes heat from the warm liquid refrigerant from the receiver. In this way the liquid refrigerant is precooled before it passes to the cooling unit.

The compressor is driven by an electric motor 46 which receives energy through the electric circuit 48 under the control of a pressure respons'ive snap acting switch 5!! controlled by a thermostat 52 located in the upper portion of the food compartment 24. This thermostat 52 causes the electric motor and compressor to operate whenever the air within the food compartment is above a predetermined temperature.

Heretofore refrigerant evaporators have customarily been metal containers for liquid refrigerant providing surfaces for contacting with the air in the food compartment as well as surfaces for supporting ice trays. Thus these evaporators were at all times required to evaporate refrigerant in order to keep the food compartment at a proper temperature and also occasionally were required to evaporate additional amounts of refrigerant when warm ice trays filled with water or other substances to be frozen were placed in the evaporator. Under such conditions a. rather high load was placed upon the compressor during the freezing period requiring a compressor and motor of a much larger size than would otherwise be required to merely maintain the food compartment at a proper temperature. Nevertheless, the demand for refrigerators capable of freezing ice cubes and desserts is such that apparently no manufacturer is willing to attempt to place a refrigerator on the market without freezing facilities. However, to provide a refrigerant apparatus sumciently large and of sufiicient capaclty to perform both the freezing and the coolof the food compartment at the same time increases the cost of domestic refrigerators considerably. If the box cooling load and the ice freezing load were distributed so that both would not occur at the same time, the capacity of the refrigerating apparatus could be reduced and the cost lowered considerably.

According to my invention I accomplish this result by providing. a congealing solution for taking care of one of the refrigerating loads during the time that freezing takes place within the ice trays. The system is so constructed that when warm ice trays filled with water are placed in the cooling unit, the refrigerating temperatures rises above the melting temperature of the congealing solution thus enabling the congealing solution to supply refrigeration to the food compartment. When the freezing of ice in the ice trays is completed, the refrigerating temperature drops and gradually begins to use its capacity for congealing the congealing solution and for cooling the food compartment.

In order to do this I so construct the evaporator that the two side walls 60 and 62 are separated for the greater part from the horizontal ice tray shelves 64, 66 and 68. The vertical walls, for example, the vertical side wall 62 is made of three sheets of metal which are held together and bonded together at their edge portions. The two sheets 10 and 12 form the walls of a refrigerant container and provide a plurality of vertical passages 14 which connect to a liquid separating chamber 76 formed between the top portions of the sheets 10 and 12. On the outer side of these two sheets there is provided a third sheet 18 and between this third sheet 18 and the sheet 12 there is a space 80 which contains a congealing solution which preferably congeals at about 15 F. The opposite vertical side wall 60 is similar to the side wall 62 just described. Taking the shelf 64 as an example of the construction of the ice tray shelves, the shelf is provided with a flat upper sheet 82 and a deformed lower sheet 84 provided with the serpentine grooves which form serpentine refrigerant passages 86 between the two sheets 82 and 84. The shelf 64 is provided with laterally extending portions 88 at both sides of the front and rear edges of the shelf which connect directly to the vertical side walls 60 and 62 of the cooling unit. This leaves a space 80 between the shelf and the side walls on either side which thus serves to prevent to a great extent heat transfer between the side walls and the shelves. The projecting portions 88 which serve to fasten the shelves to the side walls are of such a small cross section that little heat transfer takes place.

The liquid refrigerant is supplied from the pressure reducing device 40 to inclined tubes 92 and 94 which conduct the liquid refrigerant to the headers such as the header 16 at the top of the side walls. The refrigerant flows from these headers downwardly within the side walls of the cooling unit and cools the congealing solution and causes the solution to congeal as well as to absorb heat through the congealing solution from the air in the food compartment. The resulting liquid and evaporated refrigerant is conducted from the side -walls through the connecting tube 96 to one end of the serpentine passage in the lower ice tray shelf 64. The liquid and evaporated refrigerant passes completely through the passages within the shelf 64 and is then conducted upwardly through the tube 98 to the middle shelf 66 which supports an ice tray I82. The liquid refrigerant passes through the serpentine passages in the shelf 66 and some evaporates and absorbs heat from the ice tray I02 and thereafter the refrigerant passes upwardly through the tube I04 to the upper shelf 68 and thence through the serpentine refrigerant passages in the shelf 68 where it may evaporate and absorb heat from the ice tray I06 upon the shelf 68. After passing through the serpentine passages in the shelf 68 the refrigerant is returned to the compressor through the return conduits 42 and 44.

In normal operation when no ice freezing is being performed the refrigerating system operates both to cool the food compartment and to congeal the congealing solution until the congealing solution-is substantially completely congealed. This provides surfaces exposed to the air within the foodcompartment at a temperature of about 15 F. During this time liquid refrigerant is present both in the vertical side walls after the congealing solution has been congealed. The ice tray shelves are also in this open type of construction exposed to the air in the cabinet and perform some cooling of the air in the food compartment.

However, when warm ice trays filled with water are placed on the shelves, evaporation.

takes place and the temperature and pressure of the evaporated refrigerant in the ice tray shelves rises to about 24 F. This, of course, raises the 1 back pressure within the evaporator and the major portion of refrigerant flowing through the vertical side walls of the cooling unit is in a liquid state due to the low temperature of these walls. Thus, substantially all of the liquid refrigerant flowing to the evaporator under these conditions is now supplied to the ice tray shelves. During this period the cooling of the air in the food compartment is performed by the melting of the congealing solution. This congealing solutionpreferably has sumcient capacity to properly cool the box during the entire freezing period.

When the freezing is accomplished, the load on the refrigerating system is reduced and the back pressure begins to drop, causing lower and lower evaporating temperatures. Finally when the evaporating temperature goes 'below the congealing temperature of the congealing solution, the congealing solution begins to give up its heat to the refrigerant and to again congeal so that refrigeration is again stored in the congealing solution for use during another ice freezing period. Thus by this system the refrigerating load of the food compartment is removed from the compressor during ice freezing so that the compressor is merely required to supply sufficient refrigeration to freeze the ice cubes. After the freezing of the ice cubes is accomplished, the compressor then is permitted to resume the cooling of the food compartment and to congeal the congealing solution which has performed the cooling of the food compartment during the ice freezing,

By this system the required capacity of the compressor is reduced since this refrigerating load is better distributed and the excessive load normally imposed during the freezing period is reduced and a large portion deferred until such a time when the,refrigerating demand is light enough that the demand is less than the capacity of the compressor. While I have shown a system in which the refrigerant is first supplied to the box cooling surfaces and then supplied to ice tray shelves with acongealing solution in heat exchange relation with the box cooling surfaces, it is evident that refrigerant may be first supplied to ice tray shelves provided with a congealing solution in heat exchange relation therewith and thence to box cooling surfaces for directly cooling the food compartment.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Refrigerating apparatus including an insulated refrigerator cabinet, refrigerant liquefying means and refrigerant evaporating means connected in operative circuit relation, said evaporating means having a box cooling portion comprising a refrigerant containing portion and a congealing solution in heat exchange relation with each other and the atmosphere within said cabinet; said evaporating means also including an ice freezing portion having refrigerant passages connected to said refrigerant containing portion, said congealing solution freezing and melting below water freezing temperatures, said ice freezing portion of said evaporating means being separate from the box cooling portion thereof, and means for conducting refrigerant first through the refrigerant containing box cooling portion of the evaporating means and thence through the refrigerant passages of the ice freezing portion thereof.

2. Refrigerating apparatus including an insulated refrigerator cabinet, refrigerant liquefying means and refrigerant evaporating means connected in operative circuit relation, said evaporating means having a box cooling portion comprising a refrigerant containing portion and a congealing solution in heat exchange relation with each other and the atmosphere within said cabinet, said evaporating means also including an 'ice freezing portion having refrigerant passages connected to said refrigerant containing portion, said congealing solution freezing and melting below water freezing temperatures, said ice freezing portion of said evaporating means being separate from the box cooling portion thereof, means for conducting refrigerant first through the refrigerant containing box cooling portion of the evaporating means and thence through the refrigerant passages of the ice freezing portion thereof, and means actuated in response to the temperature of atmosphere within said cabinet for controlling operations of said refrigerant liquefying means.

ROLF M. SMITH.

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