US3478536A - Refrigerator - Google Patents

Description

Nov. 18, 1969 TETSUYA KOHYA ET AL 3,478,536

REFRIGERATOR Filed July 24, 1967 s Sheets-Sheet 1 i ww m m ,22 l 64 n L I i 1 -26 9H 2a 36 54 /60)62 Nov. 18, 1969 Filed July 24. 1967 TETSYUYA KOHYA ET AL 3,478,536

REFRIGERATOR 3 Sheets-Sheet 2 Nov. 18, 1969 TETSUYA KOHYA ET AL. 3,478,536

REFRIGERATOR rs sheets-sheet 3 Filed July 24, 1967 Fig.5.

m Q mn United States Patent US. Cl. 62-441 Claims ABSTRACT OF THE DISCLOSURE In order to store refrigerated food, a thermally insulating case with a thermally insulating lid is disposed Within an evaporator of the usual construction. The case is provided with a plurality of vents on each of the upper and lower portions of each side wall with the upper vents having a diameter tapered from the interior toward the exterior of the case to cause warm air to easily leave the case while the lower vents have a diameter tapered from the exterior toward the interior of the case to cause cooled air to easily enter the case. Also a space is provided between the bottom walls of the case and evaporator or between the upper wall of the evaporator and the inner top wall of the refrigerator housing for receiving ice-making trays.

The invention relates to improvements in refrigerators.

In the conventional type of refrigerators adapted to store refrigerated food therein, it has been commonly practiced to dispose a thermally insulating partition in the form of a hollow rectangular prism upon the upper surface of an evaporator to form a space providing a freezing or refrigerating chamber therebetween. Alternatively an evaporator could be made in the form of a hollow rectangular prism of which interior itself is utilized as a refrigerating chamber. In either case refrigerated food is adapted to be disposed directly onto the surface of the evaporator and therefore it is able to be stored at low temperatures during a cooling operation. However, during a defrosting operation and especially during a defrosting operation performed either by the hot gas system utilizing a gaseous refrigerant at a high temperature from the associated compressor or by a heater system utilizing heat generated by the associated electric heater, the evaporator abruptly increases in surface temperature. This may lead to a fear that the refrigerated food stored in the refrigerating chamber will be thawed out; To avoid this fear it is necessary to remove the refrigerated food from the refrigerating chamber during the defrosting operation each time it is performed. This requires the user to expand additional labor.

Also there have been previously known refrigerators of the type in which if refrigerated food is kept stored the cooling operation continued to be performed with the associated defrosting mechanism remaining inoperative. This measure results in an increase in the amount of frost formed on the exposed surface of the evaporator greatly decreasing the cooling efliciency thereby to increase the temperature within the refrigerator.

Accordingly it is a general object of the invention to eliminate the abovementioned disadvantages of the conventional refrigerators.

It is an object of the invention is provide a refrigerator of the type including an improved thermally insulating case for storing refrigerated food while preventing it from melting in the operation of defrosting the associated evaporator.

It is another object of the invention to provide a refrigerator of the type described in the preceding paragraph 3,478,536 Patented Nov. 18, 1969 including a space in which at least one ice-making tray is disposed in contact with the associated evaporator.

Briefly, the invention accomplishes the above cited objects and other objects which become apparent as the description proceeds, by the provision of a refrigerator comprising a housing assembly including an outer housing, an inner housing disposed within the outer housing to form a closed space therebetween, and a thermally insulating material filling the space. The inner housing has a front open face, a thermally insulating door for opening and closing the front open face, and an evaporator in the form of a hollow rectangular prism is disposed within said inner housing to form a cooling system along with a compressor and a condenser. A thermally insulating case composed of a thermally insulating material in the form of a hollow rectangular prism is provided and has a front open face and a bottom surface, and a thermally insulating lid for opening and closing the last-mentioned front open face thermally insulating case along with the thermally insulating lid in its closed position provides a refrigerating chamber for storing refrigerated food.

Preferably at least one ice-making tray may be disposed between the outer bottom surface of the thermally insulating case and the bottom wall of the evaporator.

The invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a schematic front elevation view of a refrigerator constructed in accordance with the principles of the invention with its door open.

FIGURE 2 is a longitudinal section view taken along the line IIII of FIGURE 1 as viewed in the direction of the arrows with the door closed;

FIGURE 3 is a fragmental cross section view taken along the line IIIIII of FIGURE 1 as viewed in the direction of the arrow;

FIGURE 4 is a fragmental front elevation view of a refrigerator illustrating another embodiment of a thermally insulating case constructed in accordance with the teachings of the invention with parts broken away;

FIGURE 5 is a cross section view taken along the line V--V of FIGURE 4 as viewed in the direction of the arrows;

FIGURE 6 is a plan view, partly in section of a modification of the invention;

FIGURE 7 is a sectional view taken along the line VII-VII of FIGURE 6; and

FIGURE 8 is a sectional view taken along the line VIIIVIII of FIGURE 7.

Referring to FIGURES 1 through 3 of the drawings, there is illustrated a refrigerator constructed in accordance with the principles of the invention. An arrangement illustrated comprises a refrigerator housing assembly of the conventional construction generally designated by the reference numeral 10 and including an outer housing 12 and an inner housing 14 disposed within the outer housing to form a closed space therebetween in which any suitable thermally insulating material 16 is filled. The outer and inner housings 12 and 14 respectively may be made of any suitable metallic material such as sheet steel and the thermally insulating material 16 may be, for example, glass fibers. A door generally designated by the reference numeral 18 is hinged at one edge to the housing assembly 10 to open and close the front opening of the latter and also includes an outer and an inner panel 20 and 22 respectively to form a closed space therebetween in which any suitable thermally insulating material 24 such as glass fibers is filled. Both panels 20 and 22 may be of the same material as that of the housings 12 and 14. In order to ensure that the door 18 hermetically closes the front opening of the housing unit 10, the inner panel 22 is provided throughout the internal peripheral edge with an annular gasket 26 adapted to abut against the corresponding peripheral edge of the front housing opening when the door 18 is in its closed position.

An evaporator 28 in the form of a hollow rectangular prism is suspended on the upper portion of the inner housing 14 by the internal top wall of the latter through fittings 30, 30 and its interior provides a freezing or refrigerating space generally designated by the reference numeral 32 and maintained at a temperature sufficient to store refrigerated food. The remaining portion of the inner housing 14 provides a food storage chamber generally designated by the reference numeral 34 and adapted to store ordinary food not required to be frozen therein. In order to maintain the freezing space 32 at a low temperature a relatively thick layer 36 of any suitable thermally insulating material such as foam polyurethane is suitable disposed below the evaporator 28 locally to heat-insulate the refrigerating space 32 from the food storage chamber 34. The layer 36 is shown in FIGURE 2 as being formed of a relatively shallow tray lined with any suitable sheet metal and also serves to receive dew drops formed.

In order to cool the interior of the inner housing 14, a cooling system of the conventional construction is provided comprising a closed motor-operated compressor 38 disposed in a machine room generally designated by the reference numeral 40 on the lowermost portion of the housing unit 10, and a condenser 42 disposed externally of the housing unit 10 on the rear side. Any suitable refrigerant compressed at an elevated temperature by the compressor 38 passes to the condenser 42 where it is condensed. Then the condensed refrigerant flows through an ordinary device for suppressing a flow of refrigerant (not shown), into the evaporator 28 where it is vaporized to cool the interior of the inner housing 14. The vaporized refrigerant returns back to the compressor 38 in the conventional manner.

As shown in FIGURES l and 2, a control panel 44 is disposed on the rear portion of the top wall surface of the outer housing 12 and includes a temperature control 46 for controlling the operation of the compressor 38. The temperature control 46 may be of the bellows type well known in the art and includes a temperature sensitive drum 48 in initimate contact with the inner bottom surface of the vaporizer 28 to be held in heat exchange relationship with respect to the latter and an operating knob 50 mounted on the control panel 44. The temperature control 46 is designed and constructed such that it functions to maintain a temperature in the refrigerating space 32 in the order of about l C. while at the same time maintaining a temperature in the food storage chamber 34 in the order of 5 C. To this end the temperature control 46 may initiate the operation of the compressor 38 when the temperature of the evaporator 28 rises for example to C. and cease the compressor 38 when that temperature lowers down to 20 C. for example.

While the arrangement illustrated comprises the freezing space and food storing chamber 32 and 34 respectively arranged to be cooled by the single evaporator 28 it will be understood that the food storage chamber 34 may be cooled by an auxiliary evaporator (not shown) operatively connected in series or parallel to the evaporator 28. In the latter case both evaporators are completely isolated from each other by any suitable means and they have the respective lids of any suitable thermally insulating material (not shown) in order to thermally isolate them from the surrounding air.

According to the teachings of the invention, the evaporator 28 is provided in the interior with a thermally insulating case or freezer compartment 52 in the form of a hollow rectangular prism having a single open space directed toward the open face of the vaporizer 28 and therefore of the inner housing 14. In other words the case 52 has an upper wall, two opposed side walls, and the bottom wall with the front case open. The case 52 is made of any suitable thermally insulating material such as foam polystyrene or the like to a wall thickness of approximately 15 mm and normally closed by a lid 54 of the same materials as that of the case hinged at one edge to the case 52 whereby the interior of the case 52 provides a freezing or refrigerating chamber 56 thermally isolated from the refrigerating space 32 as previously described.

Preferably the thermally insulating case 52 is disposed on the upper portion of the evaporator 28 adjacent one side wall leaving a gap 58 between the bottom walls of the case and evaporator for the purpose of accommodating one or more ice-making trays 60 in contact with the bottom surface of the evaporator within the gap as shown in FIGURE 1. In order for the thermally insulating case 52 to be detachably secured to the interior of the evaporator 28, L-shaped brackets 62 are fixed on that side wall of the evaporator 28 adjacent which the case 52 is to be disposed and U-shaped hangers 64 are firmly secured on the inner top wall surface of the inner housing 14 at such position that the hangers 64 have their lower legs upon which there are positioned the associated L-shaped ledge 66 fixed on the other side wall of the case 52 as disposed on the brackets 62.

In the normally cooling operation as previously described in conjunction with FIGURE 1, the evaporator 28 refrigerates the refrigerating space 32 to a temperature in the order of l5 C. while the compressor 38 is intermittently operated to maintain that temperature under control of the temperature control 46. As time goes by, the interior of the thermally insulating case 52 or the refrigerating chamber 56 disposed within the space 32 will be gradually cooled due to thermal leakag through the walls of the case 52 until it reaches approximately l5 C. substantially equal to the magnitude of temperature in the refrigerating space 32. Therefore refrigerated food is now possible to be stored in the referigerating chamber 56.

After the cooling system has continued to be operated for a long interval of time, a large amount of frost will be formed on the surface of the evaporator resulting in a decrease in cooling effect. This leads to the necessity of operating defrosting means well known in the art such as the hot gas system utilizing the gaseous refrigerant involved at a high temperature from the compressor 38 or the heating system utilizing heat generated by an electric resistor involved. During this defrosting operation the evaporator 28 abruptly rises in surface temperature which is accompanied by an increase in temperature within the refrigerating space 32. However, the thermally insulating case 52 is designed and constructed such that the thermally insulating material therefor effectively interrupts heat conduction from the heated evaporator 28 to the case as well as thermal leakage therebetween is minimized. In addition, an increase in surface temperature of the evaporator due to the defrosting ceases within a short interval of time. These ensure that even during the forcedly defrosting operation the temperature within the refrigerating chamber 56 remains substantially unchanged with the' result that refrigerated food can be safely stored in the refrigerating chamber 56.

Referring now to FIGURES 4 and 5 wherein like reference numerals designate the components corresponding or similar to those shown in FIGURES 1 through 3, there is illustrated a modification of the thermally insulating case. The evaporator 28 is disposed in the inner housing 14 so as to provide a gap 58 between the outer upper surface of the evaporator 28 and the inner top wall surface of the inner housing 14 suflicient to accommodate one or more ice-making trays 60 in contact with the evaporator.,Disposed within the evaporator 28 is a thermally insulating case 52 such as previously described extending substantially throughout the inside width of the evaporator 28. This measure ensures that the refrigerating chamber 56 or the interior of the case has an internal volume as great as possible permitting a larger amount of refrigerated food to be stored in the refrigerating chamber.

The case 52 has a front open face and in mounted at the entire front peripheral edge to a support place 68 having an opening 70 substantially equal in both shape and dimension to the front open case face with both open faces substantially aligned with each other. Then the support plate 68 is rigidily secured at both ends to the inner side walls of the inner housing 14 by having L- shaped brackets 72, 72 fixed to both the case and inner housing. In order to thermally isolate the interior of the thermally insulating case 52 from a cold storage chamber such as the food storage chamber 34 shown in FIGURES 1 through 3, the front open case face is closed by an openable lid 54 similar to the lid 54 shown in the previous figures and hinged at one side edge to the support plate 68.

FIGURES 6 through 8 illustrate a thermally insulating case similar to the case 52 shown in FIGURES 1 through 3 except for a plurality of vents extending through both side walls thereof. As shown, the case generally designated by the reference numeral 52 has an openable, thermally insulating lid 54 hinged at one side edge to the front open face and a plurality of vents 74 and 76 extending through the upper and lower portions of each side wall to permit warm air to leave the case and cold air to enter the case respectively.

As best shown in FIGURE 8, the vents 74 extending through the upper portion of each side case wall each have a diameter gradually decreasing in size or tapered toward the external wall surface thereby to permit reative- 1y warm air to easily leave the case. On the other hand the vents 76 on the lower portion of each side case wall each have a diameter tapered toward the internal wall surface thereby to permit cold air to easily enter the case 52.

With the arrangement illustrated in FIGURES 6 through *8, a portion of air cooled to a low temperature by the evaporator (not shown in these figures) during the normal cooling operation enters the interior of the case I 52 through the lower vents 76 as shown at the arrows in FIGURE 8 thereby to cool its interior or a refrigerating chamber 56 while relative warm air positioned on the upper portion of the case 62 leaves it through the upper vents 74 as shown at the arrows in FIGURE 8. This process it repeated to permit the temperature of the case 52 or refrigerating chamber to be rapidly decreased to .a magnitude at which refrigerated food can be safely stored.

On the other hand, during the defrosting operation and especially during the forcedly defrosting operation such as previously described, the evaporator abruptly rises in surface temperature but the thermally insulating material for the case 52 is effective for interrupting heat radiated by the heated vaporizer. Also because of the upper vents having the diameter tapered toward the external surface of its wall, warm air tending to enter the case 52 from the exterior is permitted only to'enter it in an extremely small amount. This ensured that the refrigerated food can be stored in the refrigerating chamber '56 during the defrosting operation.

The invention has several advantages. For example the user is not required to remove refrigerated food from the present refrigerator during the defrosting operation. The defrosting operation is possible to be performed while the refrigerated food remains stored in the refrigerator without the food melt.

What we claimis:

1. In a refrigerator comprising a housing assembly including an outer housing, an inner housing disposed within the outer housing to form a closed space therebetween, and thermally insulating material filling said space, said inner housing having a front open face, a thermally insulating door for opening and closing said front open face, and an evaporator in the form of a hollow rectangular prism disposed within said inner housing to form a cooling system along with a compressor and a condenser, the combination of a thermally insulating case composed of thermally insulating material and formed in a hollow rectangular prism having a front open face and a bottom surface, and a thermally insulating lid for opening and closing the last-mentioned front open face, said thermally insulating case being positioned within the hollow rectangular prism of the evaporator, said thermally insulating case along with said thermally insulating lid in its closed position providing a refrigerating chamber for storing refrigerated food, said thermally insulating case being constructed to allow for relatively slow thermal leakage between the thermally insulating case and said evaporator, whereby the interior of said thermally insulating case may be cooled when said evaportor is operating in its cooling mode and whereby the interior of said thermally insulat ing case remains cooler than the interior of said evaporator and does not defrost when said refrigerator is defrosted, means defining a plurality of vents extending through each of the upper and lower portions of each side wall of said thermally insulating case providing communication from the interior of said case with the exterior of said case, said plurality of vents extending through the upper portion of each side wall of said thermally insulating case having a diameter tapered toward the external wall surface and a plurality of vents extending through the lower portion of each side case wall and having a diameter tapered toward the internal side wall surface.

2. Refrigerating apparatus comprising a housing assembly having heat insulated walls, a food storage chamber within said housing, means for providing access to said food storage chamber, cooling system means for cooling said food storage chamber, a freezer compartment adapted to freeze food, means for providing access to said freezer compartment, evaporator means located entirely exterior of said freezer compartment for cooling a space exterior of said freezer compartment to a temperature below that of said food storage chamber, said evaporator means being adapted to cool the interior of said freezer compartment, means for slowing the rate of heating within said freezer compartment to a rate below that of the heating of the said space exterior of said freezer compartment, and to prevent defrosting within said freezer compartment during a refrigerator defrosting operation, said freezer compartment including a substantially vertically disposed wall, said means for slowing the rate for heating the interior of said freezer compartment below that of said space exterior of said freezer compartment including at least one vent formed in said substantially vertically disposed wall near the bottom thereof, said vent providing communication from the interior of said freezer compartment to said space exterior of said compartment, said vent having a relatively small mouth opening into the interior of said freezer compartment and gradually enlarging outwardly as it extends through said substantially vertically disposed wall to form a mouth opening exteriorly of said substantially vertically disposed wall thatis larger than the mouth opening into the interior of said freezer.

3.;A refrigerating apparatus as set forth in claim 2 wherein said means for slowing the rate for heating the interior of said freezer compartment below that of said space exterior of said freezer compartment includes at least one vent formed in said substantially vertically disposed wall near the top thereof, said vent fluidly conmeeting the interior of said freezer compartment to said space exterior of said compartment, said vent having a relatively large mouth opening into the interior of said freezer compartment and gradually enlarging outwardly as it extends through said substantially vertically disposed wall to form a mouth opening exteriorly of said substantially vertically disposed wall that is larger than the mouth opening into the interior of said freezer.

4. A refrigerating apparatus as set forth in claim 3 wherein said freezer compartment includes insulating 7 8 material positioned between the interior of said freezer 2,317,840 4/1943 Wild 62441 compartment and said space exterior of said freezer com- 2,617,268 11 /1952 Ashby 1 a1, 62\ 441 partment. 2,807,149 9/1957 Williams 62-441 5. A rengerat1ng a aratus as set forth 1n im 3 2,889,693 6/1959 Kurowski 62441 whereln the vent posrtloned near the bottom of said sub- 5 3,283,531 11/1966 Horvay et 62441 the vent positioned near the top of said substantialy verstantially vertically disposed wall slants downwardly and 3,377,941 4/1968 Jaremus 62441 tically disposed wall slants upwardly.

LLOYD L. KING, Primary Examiner References Cited UNITED STATES PATENTS 2,303,138 11/1942 Philipp 62441 2,317,775 4/1943 King 62-441 10 Us. 01. X.R.

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