US3084520A

US3084520A - Refrigerating apparatus with defrosting controls

Info

Publication number: US3084520A
Application number: US119376A
Authority: US
Inventors: James W Jacobs
Original assignee: General Motors Corp
Current assignee: Motors Liquidation Co
Priority date: 1961-06-26
Filing date: 1961-06-26
Publication date: 1963-04-09
Anticipated expiration: 1980-04-09
Also published as: GB943073A

Description

J. W. JACOBS A ril 9, 1963 REFRIGERATING APPARATUS WITH DEFROSTING CONTROLS Filed June 26, 1961 Fig. 4

INVENTOR.

Fig.

DOOR O PERATED Fig. 3

0 w W r s A M J m Y B 3,984,529 REFRIGERATIIJG APPARATUS WKTH DEFRQSTING CUNTRQifi James W. Jacobs, Dayton, Ghio, assignor to General Motors Qorporation, Detroit, Mich, a corporation of Delaware Filed June 26, 1961, Ser. No. 119,376 Claims. (Cl. 62-156) This invention relates to refrigerating apparatus and more particularly to a low cost self-defrosting refrigerator.

It is an object of this invention to so construct and arrange the parts in a refrigerator cabinet having a nonfrozen food storage compartment and a frozen food storage compartment that both compartments can be refrigerated by a single evaporator which defrosts itself during each ofii cycle and which is fully isolated from the frozen food storage compartment when the evaporator is defrosting.

Another object of this invention is to provide a refrigerator having two food storage compartments to be maintained at different temperatures wherein a single evaporator is used for cooling both compartments and wherein the evaporator is located in the warmest part of the compartments and is quickly self-defrosting during each off cycle.

More particularly it is an object of this invention to provide a refrigerator in which a single evaporator located in the uppermost part of the refrigerator is used for refrigerating the freezer compartment as well as the main food storage compartment and wherein means are provided for fully insulating the freezer compartment from the evaporator during defrosting of the evaporator.

These and further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

FIGURE 1 is a front view with parts broken away showing somewhat schematically a preferred embodiment of the invention;

FIGURE 2 is a fragmentary sectional View on an enlarged scale showing the thermostatically operated air valve;

FIGURE 3 is a circuit diagram showing the controls used; and

FIGURE 4 schematically shows the refrigerant circuit.

Referring now to the drawing wherein a preferred embodiment of the invention has been shown, reference numeral 1t} designates an insulated refrigerator cabinet having an above freezing food storage compartment 12, a freezing compartment 14 and a machinery compartment 13. The

compartments

12 and 14 are cooled by means of a single evaporator 16 located in the uppermost portion of the compartment 12. Conventional access doors and 17 are provided for the

compartments

12 and 14. The evaporator 16 forms a part of a conventional refrigeration circuit including a compressor 20, a condenser 22 and a fixed restrictor 24, as shown in FIGURE 4.

A thermostat 26 having its temperature sensing bulb located on the evaporator 16 controls the compressor. The thermostat 26' operates a double-throw switch 28 which closes the circuit to the compressor 24) when the evaporator temperature exceeds 34 F. and maintains the circuit closed until the evaporator temperature drops to 0 F., at which time the thermostat opens the circuit to the compressor, and turns on a light or lamp 3t? for a purpose to be discussed more fully hereinafter. These temperature values are given for illustration only and may be varied to suit design requirements. A conventional door 3,31,5Z6 Patented Apr. Q, 1963 are operated switch 31 is arranged in the control circuit as shown in FIGURE 3 and serves to turn on the light 30 whenever the door 15 is opened.

The freezing compartment consists of an insulated food storage chest 46 disposed in the upper part of the food compartment 12 directly beneath the evaporator 16. Whenever the evaporator :16 is cold enough to produce refrigeration, a portion of the cold air leaving the evaporator is allowed to enter the freezer chest through an air inlet opening 42 which is provided with an air valve or damper 44 which closes so as to prevent air leaving the evaporator from entering the freezer compartment 14 when the temperature of the evaporator 16 exceeds a predetermined value.

The control for the damper 44 consists of a bimetallic actuator 46 having its one fixed end arranged in thermal exchange relationship with the first two passes of the evaporator 16. The movable free end of the bimetallic element 46 has a chain or linkage mechanism 48 secured thereto and to the air valve 44 for raising the air valve at low evaporator temperatures and lowering the air valve so as to close the opening 42 at high evaporator temperatures.

During a normal run cycle, the evaporator temperature is low enough to cool the bimetallic element 46 and deflect it sufficiently to open the air valve to the freezer compartment. This allows flow of cold air into the freezer compartment 14- as well as into the food compartment 12. The thermostat 26 stops the refrigeration systern when the temperature of the evaporator reaches a predetermined low value such as zero degrees. When the thermostat has stopped the compressor, the evaporator 16 quickly starts Warming up and the relatively warm liquid refrigerant fed into the evaporator from the condenser 22 serves to quickly warm up that portion of the evaporator to which the bimetallic element 46 responds so as to cause the bimetallic element 46 to close the air valve 44. With the compressor stopped and the air valve 14 closed, the evaporator 16 will only be in thermal exchange relationship with the air from the food compartment 12. As pointed out hereinabove, when the compressor 20 is stopped, the electric light bulb 30 is energized and the heat from this bulb tends to rise into the fiuelike space between the outer wall of the freezer chest 14 and the inner wall of the main cabinet 10. Thus, this light not only induces increased circulation of the relatively warm air from the food compartment over the evaporator 16 but also adds heat to the air circulated over the evaporator 16 to further facilitate the defrosting of the evaporator.

The food compartment '12 may be provided with the usual type of food supporting shelves 50 and the freezer chest can be provided with shelves 52 which serve to sup port ice trays 54- in the path of the air circulating from the air inlet 42 to the air outlet 45. In order to simplify this disclosure, the usual hydrators, meat storage drawers, etc., have been omitted, whereas it is obvious they could be used.

The defrost water can be disposed of in any conventional manner in so far as certain aspects of the invention are concerned. For a low cost refrigerator a drip tray 56 supported on top of the freezer chest 14 directly beneath the evaporator 16 is provided as shown. A drain leads from the lowermost part of the tray 56 into a removable defrost water collecting receptacle 58 located on one of the shelves 5%. Such an arrangement makes possible a low cost refrigerator which is selfdefrosting and does not require expensive features, such as defrost heaters, insulated defrost water drain lines, bug traps, defrost water drain heaters and the like.

The damper 44 is provided with an auxiliary air flow nose,

control member 60 which partially restricts the air flow to the compartment 12 when the bimetallic element 46 lifts the damper 44- to direct cold air into the freezer compartment. When the damper 44 closes the inlet opening 42 during the defrost cycle, the member 60 moves to reduce the restriction to flow of air from the high temperature compartment over the evaporator.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a refrigerator, a cabinet having an insulated food storage compartment therein, an evaporator within said compartment adjacent the top wall of said compartment, means for supplying liquid refrigerant to said evaporator including a compressor and a condenser, means forming an insulated frozen food storage chest located directly beneath said evaporator, said chest including an insulated upper wall serving to insulate the contents of said frozen food storage chest from said evaporator, the space between the top of said frozen food storage chest and said top wall of said insulated compartment forming an air line, said frozen food storage chest having an air inlet communicating with said flue and having an air outlet communicating with said flue, a damper for controlling the flow of air through said inlet, thermal means responsive to the temperature of a portion of said evaporator for operating said damper in response to predetermined changes in the temperature of said evaporator, a light bulb disposed within said food compartment adjacent the inlet to said flue, thermal means responsive to refrigeration requirements for initiating operation of said compressor when refrigeration is required and for stopping the operation of said compressor and initiating operation of said light when no refrigeration is required, a door for said insulated food storage compartment, and switch means operated by said door for energizing said light in response to opening of said door.

2. In a refrigerator, a cabinet having an insulated food storage compartment therein, a cooling element Within said compartment adjacent the top wall of said compartment, means forming an insulated frozen food storage chest located directly beneath said cooling element, said chest including an insulated upper wall serving to insu late the contents of said frozen food storage chest from said cooling element, said frozen food storage chest having an air inlet and an air outlet, said air inlet being arranged to receive air leaving said cooling element, a damper for controlling the flow of air through said inlet, thermal means responsive to the temperature of a portion of said cooling element for closing said damper at cooling element temperatures above a predetermined value, means responsive to refrigeration requirements for initiating cooling of the air by said element when refrigeration is required and for stopping the cooling of air and initiating defrosting of said cooling element when no refrigeration is required, a light bulb in said compartment, and means for energizing said light bulb when said compressor is deenergized so asto add heat to said compartment.

3. In a low cost self defrosting refrigerator, a cabinet having an insulated food storage compartment therein, an evaporator within said compartment adjacent the top wall of said compartment, means including a compressor and condenser for supplying liquid refrigerant to said evaporator, means forming an insulated frozen food storage chest located directly beneath said evaporator, said chest including an insulated upper wall serving to insulate the contents of said frozen food storage chest from said evaporator, said frozen food storage chest having an air inlet and an air outlet, said air inlet being arranged to receive refrigerated air leaving said evaporator, a damper for controlling the flow of refrigerated air through said inlet, thermal means responsive to the temperature of a portion of said evaporator for closing said damper in response to a predetermined increase in temperature of said evaporator, a light bulb disposed within said food compartment, thermal means responsive to refrigeration requirements for initiating operation of said compressor when refrigeration is required and for stopping the operation of said compressor and initiating operation of said light when no refrigeration is required, said last named thermal means serving to initiate operation of said compressor only at evaporator temperatures above freezing whereby said evaporator is defrosted during each ofi cycle.

4. In a refrigerator, a cabinet having an insulated food storage compartment therein for storage of unfrozen foods, an evaporator within said compartment adjacent the top Wall of said compartment, means supplying liquid refrigerant to said evaporator including a compressor and a condenser, means forming an insulated frozen food storage chest located directly beneath said evaporator, said chest including an insulated upper wall serving to insulate the contents of said frozen food storage chest from said evaporator, the space between the top and sides of said frozen food storage chest and said top and side Walls of said insulated compartment forming an air flue, said frozen food storage chest having an air outlet communicating with said flue and having an air inlet communicating with said fine, a damper for controlling the flow of refrigerated air through said inlet, thermal means responsive to the temperature of a portion of said evaporator for closing said damper in response to a predetermined increase in temperature of said evaporator, and thermal means responsive to refrigeration requirements for initiating operation of said compressor when refrigeration is required and for stopping the operation of said compressor when no refrigeration is required.

5. In a refrigerator, a cabinet having an insulated food storage compartment therein, an evaporator within said compartment adjacent the top wall of said compartment, means supplying liquid refrigerant to said evaporator including a compressor and a condenser, means forming an insulated frozen food storage chest located directly beneath said evaporator, said chest including an insulated upper wall serving to insulate the contents of said frozen food storage chest from said evaporator, the space between the top and sides of said frozen food storage chest and said top and side walls of said insulated compartment forming an air flue, said frozen food storage chest having an air outlet communicating with said flue and having an air inlet communicating with said flue, a damper for controlling the flow of refrigerated air through said inlet, thermal means responsive to the temperature of a portion of said evaporator for closing said damper in response to a predetermined increase in temperature of said evaporator, and thermal means responsive to refrigeration requirements for initiating operation of said compressor when refrigeration is required and for stopping the operation of said compressor when no refrigeration is required, said last named thermal means including a thermostat responsive to the temperature of said evaporator.

References ited in the file of this patent UNITED STATES PATENTS 1,501,874 Wardenburg July 15, 1924 1,727,777 Juneau Sept. 10, 1929 2,126,285 Schaaf Aug. 9, 1938 2,346,287 Borgerd Apr. 11, 1944

Claims

4. IN A REFRIGERATOR, A CABINET HAVING AN INSULATED FOOD STORAGE COMPARTMENT THEREIN FOR STORAGE OF UNFROZEN FOODS, AN EVAPORATOR WITHIN SAID COMPARTMENT ADJACENT THE TOP WALL OF SAID COMPARTMENT, MEANS SUPPLYING LIQUID REFRIGERANT TO SAID EVAPORATOR INCLUDING A COMPRESSOR AND A CONDENSER, MEANS FORMING AN INSULATED FROZEN FOOD STORAGE CHEST LOCATED DIRECTLY BENEATH SAID EVAPORATOR, SAID CHEST INCLUDING AN INSULATED UPPER WALL SERVING TO INSULATE THE CONTENTS OF SAID FROZEN FOOD STORAGE CHEST FROM SAID EVAPORATOR, THE SPACE BETWEEN THE TOP AND SIDES OF SAID FROZEN FOOD STORAGE CHEST AND SAID TOP AND SIDE WALLS OF SAID INSULATED COMPARTMENT FORMING AN AIR FLUE, SAID FROZEN FOOD STORAGE CHEST HAVING AN AIR OUTLET COMMUNICATING WITH SAID FLUE AND HAVING AN AIR INLET COMMUNICATING WITH SAID FLUE, A DAMPER FOR CONTROLLING THE FLOW OF REFRIGERATED AIR THROUGH SAID INLET, THERMAL MEANS RESPONSIVE TO THE TEMPERATURE OF A PORTION OF SAID EVAPORATOR FOR CLOSING SAID DAMPER IN RESPONSE TO A PREDETERMINED INCREASE IN TEMPERATURE OF SAID EVAPORATOR, AND THERMAL MEANS RESPONSIVE TO REFRIGERATION REQUIREMENTS FOR INITIATING OPERATION OF SAID COMPRESSOR WHEN REFRIGERATION IS REQUIRED AND FOR STOPPING THE OPERATION OF SAID COMPRESSOR WHEN NO REFRIGERATION IS REQUIRED.