US2769319A - Two temperature household refrigerators - Google Patents

Description

Nov. 6, 1956 c. F. ALSING 2,769,319

" TWO TEMPERATURE HOUSEHOLD REFRIGERATORS Filed Feb. 18, 1952 5 Sheets-Sheet 1 IN VEN TOR.

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TWO TEMPERATURE HOUSEHOLD REFRIGERATORS Filed Feb. 18. 1952 3 Sheets-Sheet 5 Pressure Gas .4. ,g; .15;

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BY W K M Q'iiormgy United States Patent TWO TEMPERATURE HOUSEHOLD REFRIGERATORS Carl F. Alsing, Evansville, Ind., assignor, by mesne assignments, to Whirlpool-Seeger Corporation, St. Joseph, Mich., a corporation of Delaware Application February 18, 1952, Serial No. 272,175

11 Claims. (Cl. 62116) The present invention relates to two-temperature household refrigerators, and is particularly concerned with the provision of an improved refrigerator structure and an improved refrigeration system for automatically cooling a frozen food zone constantly at a below freezing temperature, while at the same time maintaining a suitable temperature above freezing for food storage by means of two separate evaporators or evaporator sections under various ambient room temperatures.

One of the difficulties of maintaining a freezing zone at a suitable low temperature while cooling a food storage space to a suitable higher temperature lies in the fact that when the motor compressor is controlled responsive to the temperature and requirements of the frozen food zone, such a system will result in the over cooling of the food storage space whenever the refrigerator is used in a low temperature ambient.

One of the objects of the invention is the provision of an improved refrigeration system in which the volume of the high side compressor housing, the amount of oil in the system, the volume of a frozen food evaporator, the volume of an above-freezing evaporator, and the amount of refrigerant charge are so proportioned that the refrigeration can be confined principally to the ice freezing or frozen food storage area during low ambient operating conditions, and so that the refrigeration can be automatically extended to cover the above-freezing evaporator under high ambient conditions.

Another object of the invention is the provision of an improved refrigeration system in which advantage is taken of the tendency of mineral oil to absorb refrigerant, such as Freon (F-12) in an amount which varies with temperature, so that as the compressor becomes heated, due to longer running periods under higher temperature ambients, more refrigerant is made available to the system by the fact that the oil liberates the refrigerant at higher temperatures and absorbs more refrigerant at lower temperatures.

Another object of the invention is the provision of an improved refrigeration system provided with an evaporator section used for cooling a frozen food zone and for freezing ice; and a second evaporator section used for cooling a food storage space to above-freezing temperatures, and in which the refrigerant goes first to the frozen food evaporator section, and in which the second evaporator section for cooling the food storage space is provided with a temperature responsive switch for controlling the compressor, and only with suflicient refrigerant to maintain the latter space at a suitable temperature under all ambient room temperatures. A second temperature responsive switch may have its bulb adjacent the first freezing evaporator, and the switches may be connected in parallel so that the demands of both must be satisfied by the compressor.

Another object is the provision of an improved domestic refrigerator of the class described in which the evaporator area under refrigeration may be automatically a varied, depending upon the ambient conditions, and in which the evaporator may be provided with an extended area to accumulate frost and to keep the cabinet from becoming excessively wet during high humidity operating conditions.

Another object of the invention is the provision of an improved household refrigerator structure and arrangement in which the refrigerated space extends from the bottom of the cabinet to the top of the cabinet, and in which the lower end of the cabinet is employed for the coldest Zone for storing frozen food, neXt above which is the zone for ice cubes, and thereafter extending upward toward the top of the cabinet the temperature gradually increases, thereby making the cabinet more efficient because of the natural tendency of the upper end of the cabinet to be warmer and of the lower end of the cabinet'to be colder; and placing the food storage spaces so that those which are used most frequently are at the most convenient levels in the cabinet.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the three sheets of drawings accompanying this specification,

Fig. l is a front elevational view of a household refrigerator cabinet in the open position, without its door;

Fig. 2 is a diagrammatic view in perspective of the evaporator system, showing the course of the refrigerant through the two evaporator portions or evaporator sections, or what may be called two separate evaporators;

Fig. 3 is a diagrammatic, vertical, cross-sectional view, showing the arrangement of the shelves and other contents of the cabinet in one embodiment of the invention;

Fig. 4 is a front elevational view of the evaporator system;

Fig. 5 is a side elevational view of the evaporator system; and

Fig. 6 is a diagrammatic view of the entire refrigeration system, showing the condition of the system at low ambient temperature.

Referring to Figs. 1 and 3, 10 indicates a household refrigerator embodying an arrangement and refrigeration system according to the invention.

The cabinet includes an outer metal shell 11 and an inner liner 12 insulated from each other by suitable insulation 13, and having a front door opening 14, which 17 passes up a condenser flue 18, having condenser coils 19.

The cabinet is supported upon a plurality of foot pads 20; and its bottom may be provided with a condensate pan 21 arranged to receive condensate and to permit the circulation of air over it.to evaporate the condensate. Thus the cabinet has a drainage aperture at 22 in its bottom, comprising a tube passing through the liner and the shell leading to the pan 21.

The cabinet is preferably provided with a suitable lower evaporator 23, disposed immediately above a basket or drawer 24, providing a frozen food storage space. The lower evaporator 23 may be substantially as shown in Figs. 4 and 5, in which an aluminum plate 25 is provided with a plurality of welded angle brackets 26, by means of which the plate is supported from the side walls of the liner.

The plate may have an easy bend at 27, at the rear of the liner, and a depending portion 28, and may be provided with a plurality of backwardly and forwardly extending sinuous tubes 29, beginning at an inlet 30, Fig. 2, and terminating at the outlet 31.

The refrigerant goes to the lower evaporator section 23 first and is thereafter carried upward by a tube 32 to the upper evaporator section 33. The upper evaporator section may be a flat aluminum plate as shown at 33a in Fig. 3, or it may be a three-sided member as shown in Fig. 2, with a rear plate portion 34 and two side plates 35 and 36 integrally joined together.

This upper evaporator may be substantially as shown in Figs. 4 and 5, and the tube 32 may communicate with a forwardly extending portion 37 on the left side, an upwardly extending portion 38 and a backwar'dly extending portion 38a.

Thereafter the tube which is integrally welded to the plate may extend horizontally at 39 across the back plate 34 and forward at 40 on the side plate 36. It extends downward and backward at 41 on the side plate 36, and across the lower part of the back plate 34 at 42, and communicates with a downwardly extending tube 43.

The tube 43 may lead into a suitable cylindrical re ceiver 44, Which is connected with an outlet or suction tube 45. The receiver 44 may be supported on top the plate 25, adjacent the easy b'end 27, and may be secured by a pair of metal straps 46 riveted to the plate 25.

The tube 45 preferably turns its open end upward, as indicated in Fig. 4, at 47 inside the receiver 44 for the purpose of causing the suction tube 45 to aid in separating liquid from vapor in the receiver 44.

The evaporator section 33 has its rear plate 34 provided with a plurality of apertures 48, by means of which it is attached to the liner wall adjacent the top 49 of the liner.

The amount of tubing in proportion to the extended area of the aluminum plates 34, 35, 36 is preferably substantially as shown to provide the upper evaporator with an extended area capable of gathering frost and preventing high humidity conditions in the food storage space which exists in the upper part of the cabinet.

The cabinet is preferably provided with a pair of insululating shelves 50, 51 arranged parallel to each other and spaced from each other, and constructed of suitable material such as sheets of glass or molded plastic.

The sh'elves 50, 51 are spaced slightly at their rear edges 52 from the back wall 53 of the liner to permit a limited circulation of air and a passage of condensate down the rear wall of the liner.

The shelves 50, 51 are spaced from the top of the evaporator section 23 by an amount suitable for the reception of ice trays 54 above the evaporator section 23.

The shelves 50, 51 may be carried by suitable insulating plastic guides mounted on the sidewalls of the liner 12, and the opening between the bottom of the cabinet and the lower shelf 51 may be closed by providing the drawer 24 with a suitable impervious front facing 55, and with a pivoted door on the top of the drawer facing, closing off the front of these spaces to prevent the access of air to them. Both the drawer facing and the pivoted door on it are preferably made of molded heat insulating plastic.

Above the partition 50 there may be provided a pair of drawers 57 and 58 for storage of fresh vegetables, these drawers being covered by a pair of glass covers 59. The cabinet may have an upwardly extending metal wall or partition 60 carrying the guides for the glass covers 59 and also carrying guides 61 for a bottle basket.

Above this the cabinet may be provided with a plurality of wire shelves 62, 63, each shelf having its laterally extending frame memb'ers extending into rubber or plastic grommets 64 mounted in holes in the liner wall.

This places the milk bottle tops at about finger tip level for the ordinary user; and the reason for this is that the milk bottles are then in the coldest part of the food storage space, which is available above the crispers; and

milk bottles are handled perhaps more frequently than any other article in the refrigerator.

The shelves 62 are also at a very convenient location, as they hold other articles of food which are handled more frequently than meats or ice cubes; and they are also at the most convenient height.

In the upper part of the cabinet the upper evaporator 33 is located adjacent the top 49 of the liner by having its side plates 35, 36 secured to the liner wall by means of screw bolts 70. The evaporator 33 is closed at the top, but it may be open. It is also open at the bottom for free circulation of the air into the interior of this evaporator, which is provided with another wire shelf 71 and with a transverse bearing rod 72 rotatably supporting an evaporator cover 73.

Below this evaporator there is located on the side walls and rear of the liner the drain trough 74, which drains downwardly toward a central pipe 75 leading into a funnel 76, which is provided with a pipe 77 for conducting condensate to the bottom of the cabinet, where it passes through aperture 22 into drain pan 21.

The present refrigerator preferably includes a refrigerating system in which the volume of the space in the compressor for gas and for oil and in the condenser and the evaporator sections is proportioned relative to the amount of refrigerant and oil to accomplish special results, as follows:

The frozen food shelf 23 is refrigerated first through a series circuit by refrigerant coming to it from the condenser tubing 19 through the capillary tube 33. After passing through the coils of the shelf 23, the refrigerant passes vupward to the evaporator 33, which may in some cases consist of a flat plate or of tubing on the outside of the liner; and the upper evaporator for the food storage space is refrigerated next with such r'efrigerant as is available.

The freezing shelf 23 will normally receive full refirigeration for the maximum length of time; and the compressor 17 may be controlled by a single thermostatic switch, which has its b-ulb located adjacent the top evaporator near the inlet.

Two bulbs and switches may be employed, one on each evaporator, connected in parallel so that both controls must be satisfied.

Referring to Fig. 6, this a diagrammatic view, showing the refrigeration system and its content at one stage of the operation. All of the parts have been given numerals corresponding to the previous description; and the condition of the refrigeration system at low ambient temperatures is indicated by means of a color code corresponding to that used in the trade-mark rules.

At low ambient temperatures the oil in the system will absorb an amount of refrigerant which will cause the upper evaporator normally to be in a starved condition. At higher ambient temperatures less refrigerant is absorbed in the oil; and, therefore, more refrigerant is available for the upper evaporator, which is ordinarily cooled mostly by superheated gas.

net and the size of the conduits used. One example of the volumes of these spaces is as follows:

cc. Gas volume in the compressor housing 1230 Oil volume in the compressor sump 400 Volume of the condenser tubes 260 Volume of the tubing of the upper evaporator 65 Volume of the tubing of the lower evaporator Volume of the lower evaporator header 215 The distribution of charge in such a two-temperature system may be substantially as follows: At 110 degree ambient or room temperature with the cold control set in the coldest position, the suction pressure was 4 pounds; the head pressure 205 pounds; and the compressor housing temperature 206 degrees. Under these conditions it is found that there are about 2 ounces of Freon (F-l2) absorbed in the oil; 3%. ounces of vapor in the compressor housing and condenser; 4 ounces of refrigerant in the lower evaporator; 2.5 ounces of refrigerant in the top evaporator; and 6 ounces of refrigerant in the header.

Thus it will be apparent that at a very warm room temperature there is very little refrigerant absorbed in the oil. Both evaporators were receiving refrigerant, most of it being used in the lower evaporator, but both evaporators are thoroughly refrigerated.

At 70 degrees ambient or room temperature, with the cold control set in the warmest position, at the cut-in of the thermostat, starting the compressor, the suction pressure is 28 pounds and the head pressure 73 pounds. 'The motor housing temperature is 95 degrees F. Under these conditions it is found that there are 7 ounces of refrigerant absorbed in the oil, 2 ounces of refrigerant in the motor housing and condenser tubes, 3 ounces of refrigerant in the lower evaporator tubes, and 6 ounces of refrigerant in the header. Refrigerant in the upper evaporator is mostly gas.

Thus it will be observed that at a lower and more usual ambient temperature 7 ounces of Freon have been absorbed by the oil, as distinguished from 2 ounces at abnormally hot temperatures. The upper evaporator is substantially without refrigerant unless it needs it, at which time the compressor will operate, and there are only 3 ounces in the lower evaporator, as distinguished from 4 ounces in the first example.

At 70 degrees F. ambient or room temperature, with the cold control set in the warmest position, at the cutout of the thermostat, which stops themotor compressor, there was a suction pressure of 4 pounds, a head pressure of 105 pounds; and the motor housing temperature was 97 degrees F. The running of one cycle of the motor compressor has increased the motor housing temperature two degrees.

Under these conditions it was found that there were 8 ounces of refrigerant absorbed in the oil, 2.7 ounces of refrigerant in the motor housing and condenser tubes, 4 ounces of refrigerant in the lower evaporator tubes, 1 ounce of refrigerant in the upper evaporator tubes, and 2.3 ounces of refrigerant in the header.

Thus the decreased temperature of the oil has resulted in an increased absorption of refrigerant after operation of the motor compressor; and the major portion of the refrigerant is still in the lower evaporator.

Under low room temperature conditions there is quite a high percentage of refrigerant absorbed in the oil; and the unit starts up with the top evaporator completely dry and the lower evaporator partly dry. Under high room temperature conditions there is less refrigerant absorbed by the oil; and the unit starts with the bottom evaporator full and the top evaporator partly full.

The amount of refrigerant absorbed by the oil causes less refrigerant to be available for the upper evaporator, which cools the food storage space; but there is always sufficient refrigerant to cool the freezing plate or lower evaporator, which is constantly maintained at a below freezing temperature.

The great difficulty in the prior art devices has been to keep the main portion of the cabinet from being overcooled under low room temperature conditions. This difficulty is eliminated in the present invention by proper proportioning of the oil and refrigerant and, the volumes of the upper and lower evaporators so that the upper food storage evaporator for above-freezing temperatures is starved of refrigerant progressively asthe room temperature decreases.

Advantage is taken of the fact that lower per cent of running time of the motor compressor decreases the temperature of the mineral oil, which causes it to absorb more refrigerant at lower room temperatures, when the above-freezing food storage space does not need so much refrigeration.

It will thus be observed that I have invented an improved cabinet arrangement and refrigeration system, in which all of the storage spaces are arranged so that the subfreezing food storage, to which access is had least often, is at the lowermost part of the cabinet; and the ice cubes, which are next in order of frequent access, are just above the freezing food storage. Just above this there are located the meat storage pans, and above them the bottle racks, which are located at finger tip level, since access is had very often to milk bottles. Above these are the shelves for other articles, which are at the higher temperature and are more accessible than the other articles just mentioned.

The food storage cooling evaporator is located at the top, warmest part of the cabinet, thus stimulating the air circulation as it cools the air, which then tends to pass downward. The frozen food storage, which is below freezing temperature, is located lowermost, in that part of the cabinet which should naturally be coolest; and the tendency for cold air to spill out is naturally reduced.

The ice cube space and frozen food space have their front closed by suitable closures, and may be doors or by fronts attached to the frozen food basket, so that a minimum of cold air is lost from these spaces when the main door only is opened.

The present refrigerator cabinet requires a minimum amount of baffling to secure the proper temperature for frozen food, making ice, and for above-freezing storage, yet it can be operated by one thermostatic control switch responsive to the temperature of the upper plate.

It will be understood that the specific arrangement of the crispers, meat storage, milk bottles, and other baskets may be varied, while still employing the other features of the present invention.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, What I claim as new and desire to secure by Letters Patent of the United States, is:

l. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first belowfreezing coils and a food storage Zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not ab sorbed and available for cooling said first coils is sufficient to maintain a below-freezing temperature in the below-freezing Zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is suificient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling efiect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said second coils being mounted on the outside of a substantially rectangular sheet metal member of suflicient length to extend from side to side inside the cabinet at the top of the cabinet, and to extend forwardly on each of the side walls of the cabinet to a point adjacent the front of the cabinet, said member being spaced from the inside of the cabinet by said second coils, leaving the rest of the cabinet space substantially open for storage of articles to be refrigerated in said food storage zone.

2. A. refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first below-freezing coils and a food storage zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is sufficient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is sufiicient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling effect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said second coils being mounted on the outside of a substantially rectangular sheet metal member of sufficient length to extend from side to side inside the cabinet at the top of the cabinet, and to extend forwardly on each of the side walls of the cabinet to a point adjacent the front of the cabinet, said member being spaced from the inside of the cabinet by said second coils, leaving the rest of the cabinet space substantially open for storage of articles to be refrigerated in said food stora e zone, the said cabinet being provided on its inside adjacent the lower edge of said metal member with a trough extending below the lower edge of said metal member to receive drainage of condensate and conduct it to the rear of the cabinet, a conduit located at the rear of the cabinet for carrying said drainage to a point on the outside of said cabinet below the cabinet, and an evaporation pan located below the cabinet for receiving said condensate, and having a substantial area for exposing the condensate to the passage of air and evaporating it.

3. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first belowfreezing coils and a food storage zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor com prising a motor,'a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is sufficient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is suflicient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling effect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said cabinet having an outer shell and an inner liner, and the said second coils being located at the upper end of said liner and mounted on a sheet metal evaporator extending across the back of the liner and forwardly on both side walls of the liner and spaced from the liner by said second Coils.

4. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first belowfreezing coils and a food storage zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is suflicient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is sufiicient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufiicient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling effect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said cabinet having an outer shell and an inner liner, and said first below-freezing coils being mounted on a lower freezing evaporator carried by said liner and comprising a sheet metal shelf having a depending rear portion located forwardly of the back wall of said liner.

5. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first belowfreezing coils and a food storage zone cooled by second '9 coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is sufficient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is sufficient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling effect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said cabinet having an outer shell and an inner liner, and said first below-freezing coils being mounted on a lower freezing evaporator carried by said liner and comprising a sheet metal shelf having a depending rear portion located forwardly of the back wall of said liner, the said shelf defining a frozen food space below it and being adapted to carry ice trays above the shelf, and a frozen food drawer located in said frozen food space below said shelf and having a front closure on said drawer for closing saidfrozen food space.

6. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first belowfreezing coils and a food storage zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is sufiicient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is sufficient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling effect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said cabinet having an outer shell and an inner liner, and said first below-freezing coils being mounted on a lower freezing evaporator carried by said liner and comprising a sheet metal shelf having a depending rear portion located forwardly of the back wall of said liner, the said shelf defining a frozen food space below it and being adapted to carry ice trays above the shelf, and a frozen food drawer located in said frozen food space below said shelf and having a front closure on said drawer for closing said frozen food space, the said frozen food drawer supporting a horizontally pivoted door on the upper edge of its front closure, said pivoted door closing the space for ice trays above said shelf.

7. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first below-freezing coils and a food storage zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is Sllfilcient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is sufficient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling elfect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said cabinet having an outer shell and in inner liner, and said food storage zone being separated from said below-freezing zone by a pair of insulating partition plates carried by the liner and spaced from each other to provide an air space between them and spaced from the liner to permit condensate to drain down the liner wall, said liner supporting a plurality of drawers above said partition plates, and said drawers having insulating cover plates above the drawers to provide an upwardly decreasing heat gradient in the food storage zone between said below-freezing coils and said second coils.

8. A refrigeration system comprising an insulated cabinet having a below-freezing zone cooled by first below-freezing coils and a food storage zone cooled by second coils communicating without restriction with said first coils in series, to cool said second coils only with refrigerant from said first coils, a motor compressor comprising a motor, a compressor and a housing enclosing the motor and compressor, a condenser and a restrictor connected in this order to said first coils, said second coils communicating with the suction inlet of said compressor and said compressor having an oil sump, a charge of oil in said sump and a charge of refrigerant of a type miscible with and absorbed by said oil in said system, a portion of said refrigerant being absorbed in said oil at ordinary ambient temperatures, a larger portion being absorbed at lower ambient temperatures, and a lesser portion absorbed at higher ambient temperatures, the volumes of said coils, said oil charge and said refrigerant charge being proportioned so that the amount of refrigerant not absorbed and available for cooling said first coils is sufficient to maintain a below-freezing temperature in the below-freezing zone at the highest ambient contemplated, and the amount of refrigerant available for said second coils is suificient for cooling the food storage zone at a suitable above-freezing temperature at ordinary ambients, and is sufficient for increasing proportionately the cooling effect of said second coils at higher ambients due to the release of absorbed refrigerant from the oil at higher ambients, but decreasing the cooling effect of said second coils proportionately at lower ambients, due to greater absorption of refrigerant at the lower ambients, to avoid overcooling or undercooling the food storage space while maintaining below-freezing temperatures in the freezing zone, the said cabinet having an outer shell and an inner liner, and said first below-freezing coils being mounted on a lower freezing evaporator carried by said liner and comprising a sheet metal shelf having a depending rear portion located forwardly of the back wall of said liner, said lower freezing evaporator supporting a receiver located near its rear edge and connected between the second coils and the compressor suction inlet.

9. A two-temperature household refrigerator, comprising a cabinet having an outer shell extending substantially to the floor, and having an inner liner spaced from the outer shell and separated by insulation, said liner and shell having a front door opening and an insulated door closing said opening, a plurality of insulating partition members carried by said liner in closely spaced relation to each other adjacent the lower end of said liner but spaced from said lower end sufficiently to define an upper ice tray space and a larger lower frozen food space, a lower below-freezing evaporator carried by said liner below said partition members and spaced from the lower partition members sufficiently to receive ice trays above said lower evaporator, a frozen food drawer below said lower evaporator, a front closure carried by said drawer for closing said space below said partition members, a pair of crisper drawers carried by guides on said liner and located above said partition members to be cooled by said lower evaporator, insulating covers carried by said guides above said crisper drawers, and a plurality of open wire supporting members carried by said liner above said crisper covers, the said space above said partition members having an upwardly increasing heat gradient, due to the cooling effect of said lower evaporator which effect is diminished successively in an upward direction by the interposed partition members, drawers and covers therefor to provide a suitable temperature for storage of foods above freezing at upwardly decreasing temperatures, said partition members and drawer covers being spaced from said door, liner, side walls and rear walls sufiiciently to permit liner condensation to drain to the liner bottom, said liner bottom sloping to a drain aperture which drains to an evaporation pan below said cabinet.

10. A two-temperature household refrigerator comprising a cabinet having an outer shell extending substantially to the fioor, and having an inner liner spaced from the outer shell and separated by insulation, said shell and liner having a front door opening and an insulated door closing said opening, a lower subfreezing evaporator, comprising a metal sheet provided with lower refrigerant tubing, spaced from the bottom of the liner to define a frozen food storage space, a frozen food drawer located below said lower evaporator and an insulating partition located above said evaporator and spaced sufficiently to define an ice tray space above the evaporator and separating the interior of the cabinet into a lower subfreezing compartment and an upper above-freezing food storage compartment, and an upper evaporator carried on the inside of the liner at its upper end for cooling the above-freezing food storage space, said upper evaporator comprising a metal sheet provided with refrigerant tubing on its outer side adjacent the liner and extending from the door opening backwardly across each side wall of the liner and across the back of the liner, the said upper and lower evaporators having their refrigerant tubing in unrestricted communication with each other, a motor compressor having an oil sump in the lower part of its housing and having refrigerant under pressure in the upper part of its housing, a condenser and a capillary restriction connected to the outlet of said compressor and connected to the inlet of said lower evaporator tubing, the refrigerant passing from the lower evaporator tubing to the upper evaporator tubing, and a suction conduit from said upper evaporator to the inlet of said compressor to form a refrigerant circuit, a charge of lubricating oil in said oil sump and a limited charge of oil absorbent refrigerant in said circuit, the refrigerant charge being proportioned to the volume of the refrigerant space, to cool the below-freezing space constantly at below-freezing temperatures and diminishing the cooling effect of the space above said partition members as the ambient temperatures lower, due to the absorption of refrigerant in the oil, to prevent overcooling of said latter space.

11. In a household refrigerator, an insulated cabinet having an outer shell and an inner liner separated by insulation, and provided with a door opening and an insulated door, said liner carrying a plurality of guides on its side walls, a pair of insulating sheet partition members carried by said guides, with a dead air space between them, forming an upper above-freezing zone and a lower below-freezing zone, an upper evaporator of sheet metal and tubing, extending across the sides and back of the liner at the top of said upper zone, a lower shelf evaporator of sheet metal and tubing, located below said partition members and providing a shelf for ice trays above said lower evaporator, and a space for frozen food storage below said lower evaporator, a plurality of drawers provided with covers located above said partition members, and a plurality of open shelves located above the drawers for storage of food to which frequent access is had, the cabinet interior having a temperature gradient increasing from the lower shelf evaporator to the top with suitable temperatures for storage of various foods at proper temperature, the least used frozen storage being at the bottom, with the ice cubes next upward, the drawers being arranged above the partition at temperatures just above freezing, and the shelves being at finger tip height and suitable temperature for various foods to which access is had most often, a frozen food drawer slidably mounted below said lower evaporator, an impervious facing carried by the frozen food drawer to close the space under the lower evaporator, and a pivoted door carried by said impervious facing and closing the space above said lower evaporator and below said partition and giving separate access to the ice trays by opening the pivoted door.

References Cited in the file of this patent UNITED STATES PATENTS 2,292,405 Reeves Aug. 11, 1942 2,386,919 Tobey Oct. 16, 1945 2,416,354 Shoemaker Feb. 25, 1947 2,451,903 Bauman Oct. 19, 1948 2,458,048 Bauman Jan. 6, 1949 2,459,311 De Jarlais Jan. 18, 1949 2,515,892 Philipp July 18, 1950 2,578,906 Tobey ec. 18, 1951 2,608,835 Grubb Sept. 2, 1952 2,663,999 Alsing Dec. 29, 1953 2,695,502 Muffiy Nov. 30, 1954 2,697,916 Alsing Dec. 28, 1954

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