US2768505A - Two temperature portable refrigerator - Google Patents

Description

Oct- 30, 1956 H. B. GooDwIN Two TEMPERATURE PORTABLE REFRIGERATOR 2 Sheets Filed April 27,

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BY if@ ATTORNEYS.

Oct. 30, 1956 H, B, GOODWIN 2,768,505

TWO TEMPERATURE PORTABLE REFRIGERATOR Filed April 27, 1954 2 Sheets-Sheeb 2 is, J4

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ATTORNEYS.

United States Patent O TWO TENIPERATURE PORTABLE REFRIGERATOR Application Api-i127, 1954, Serial No. 425,783

Claims. (Cl.` 621-2) This invention relates to a refrigerator and more particularly to a refrigeratorin which solid carbon dioxide, commonly known as Dry Ice, may be used as the refrigerant.

There are many situations in which it is desirable toy provide a refrigerator, which refrigerator is selfcontained and readily portable so that foods may be stored therein and transported Without danger of spoilage forl a matter of several days.

It is also desirable to provide a refrigerator as above outlined which 4by `a simple adjustment can be made to maintain a normal refrigeration temperature of between 35 Land 40 F. o r a freezing temperature of 10 F., so that it lmay serve either for the storage of ordinary fQQds at ordinary refrigerated temperatures or in the alter-native for frozen foods at freezing temperatures.

TWith the foregoing considerations in mind, it is an objm t of my invention to provide a refrigerator which is yparticlllarly adapted to the use of Dry Ice as the refrigerant although other refrigerating media can be used. Itis another object of the invention to provide a refrigerator havinga food storage chamber and a refrigerant compartment insulated therefrom and to provide a passagethrough which cold air from the refrigerant compartment may flow downwardly through the refrigerated chamber and ultimately back 'into .the refrigerant cornpartment under control of a valve.

It is still another object of the invention to provide a novel thermostatically controlled valve to control the ow of l-cold air in said refrigerator.

`These and various other objects of the invention which will be pointed out in more detail hereinafter or which will become apparent to one skilled in the art upon reading these specifications, I accomplish by that certain construction and arrangement of parts of which I shall .nowdescribe an exemplary embodiment.

Reference is made to the drawings forming a -part hereof and in which: Y

Figure l is a top plan view of the device.

Figure 2 is a fragmentary front elevational View of the same with the door open. v i f Figure 3 is a vertical cross-sectional View taken o n the Aline 3-3 of Figure 2 but showing the door closed.

Figure 4 is a horizontal cross-sectional view 4taken on the line 4 4 of Figure 3.

Figure 5 is a perspective View of one of the handle members.

Figure 6 is a fragmentary exploded view similar to Figure 3 showing the door .of the refrigerant compartment open and the refrigerant container removed.

Figure 7 is a fragmentary detail view in cross section showing the vent connection for the yrefrigerant compartment. Figure 8 is a fragmentary cross-sectional view -showing the thermostatically actuated valve lin elevation on a greatly enlarged scalenwith respect to the showing in Figure v3.

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Figure 9 is a bottom plan View of the thermostatically actuated Valve as seen from the line 9 9.

Figure 10 is a fragmentary cross-sectional view taken on the line iti-lil of Figure 9, and

Figure ll is a perspective view of one of the thermostat plates.

Briey, in the practice of my invention I provide a box of insulating material having a door fitting tightly against the box by means of interengaging rubber gaskets or the like and within the box I provide a horizontal shelf of insulating material dividing the box into an upper refrigerant compartment and a lower refrigerated chamber. This shelf is shorter than the depth of the box so `as to provide clearance between the front of the shelf and the inside of the door for convection currents. More or less central-ly toward the rear of theshelf I provide an aperture through which refrigerated air from the refrigerant compartment may flow downwardly into the refrigerated chamber by convection. Flow through this aperture is regulated by a valve which is actuated by a thermostat disposed within the refrigerated chamber. By means of a sloping baille the cold air passing through this aperture is directed toward the rear of the refrigerated chamber whence it flows downwardly and across the bottom of the chamber and upwardly past the front edge of the shelf. A secondary circulation returns above the sloping back baffle above mentioned and is recirculatcd.

The front of the refrigerant compartment is provided with an insulated door which is inwardly spaced from the main door of the box and which is spaced slightly downwardly from the top of the box so that the warmed air 'lying inside the main door and past the front of the shelf passes upwardly betweenthe two doors and returns to the refrigerant compartment over the top of the inner door.

Referring now in greater detail to the drawings, the box comprises a top wall 10, side walls 11 and 12,` a rear wall 13 and a door I4. The door is preferably attached to the box by means of a piano hinge or the like at15. A rubber gasket or the like at i6 is provided on the front face ofthe top, bottom and side walls and a rubber gasket 17 is provided on the inside of the door. When the door is shut, the gaskets 16 and 17 interengage to seal the box tightly'.

A vent pipe 1S extends from the back wall 13 adjacent the top and handle members are provided for lifting the device as indicated generally at 1S?. The members 19', as best seen in Figure 5, are bail-like elements pivoted on straps 2d which are secured to the top ofthe box within the recess'Zl. The straps 30 are undercut as at 22 so that webbing straps may be passed under them to secure the box in position on an airplane or the like.

The .interior of the box is divided by means of a horizontal insulative shelf 30 into an upper refrigerant compartment 31 and a lower refrigerated chamber 32. It will be clear from Figure 3 that the shelf 30 is shorter than the depth of the box so as to leave a clearance 33 between the front of the shelf and the inside of the door 14.

Adjacent the rear of the shelf 30 and substantially centrally thereof I provide the aperture 34 throngh which cold air from the compartment 31 may owlinto the chamber 32. This flow is directed rearwardly by the rearwardly sloping baffle 35 which is suitably secured to the shelf 30 by means of the studs 36,. The ow of air through the aperture 34 is controlled by the thermostatically actuated rvalve shown in greater detail in Figures 8 to 1.1 inclusive and will be described in greater detail hereinafter. f

Hinged to the vtop 10 of the box is the supplementary door 40 which is of insulating material. The hinges 'are indicated at 41 and they are designed to provide a space 42 between the top of the supplementary door 40 and the inside of the top of the box. The front edge of the shelf 30 is rabbeted, as best seen in Figures 3 and 6, to accommodate the supplementary door 40 which is provided at the bottom with the rubber bumper 43. The door 40 is locked in place by means of the latches 44 which engage in loops 45 on the front of the shelf. The door 40 thus seals off the compartment 41 except at the top where air may flow through the space 42.

It will now be clear that a cooling medium is disposed within the compartment 31 and foodstutfs to be refrigerated are disposed in the chamber 32 (and this may be on racks 46 if desired). A convection circulation of air will be set up as indicated by the arrows in Figure 3. Thus air chilled by the refrigerant medium tlows downwardly through the aperture 34 over the bafe 35 and down inside the rear wall 13. Thence the air tlows through and under the foodstuffs on the rack 36 toward the front of the chamber 32 and in an upward direction as it reaches the door 14.

Some of the circulating air will pass back over the baffle 35 and be recirculated through the chamber 32 by the principal flow of the air which has picked up heat from the foodstuffs being refrigerated, upwardly inside the door 14 and between it and the front of the shelf 30 and the supplementary door 40 and iinally through the space 42 back into the compartment 31.

It will be understood that any refrigerant medium may be used, including even the evaporator coils of a mechanical refrigerator but the potentialities of the invention may be more fully realized by the use of solid carbon dioxide or Dry Ice, as it is more commonly called. If Dry Ice is used, the box may be charged with Dry Ice as hereinafter to be described and from actual tests I have determined that the predetermined cold temperature will be maintained within the refrigerated chamber 32 regardless of the ambient temperature or changes therein for as many as 5 or 6 days. I will therefore describe the invention particularly in connection with the use of Dry Ice.

The Dry Ice is placed in a container 50 which is removable from the chamber 31. As will be clear from the drawings, the Dry Ice receptacle 50 is provided with spacing members 51 on its side and bottom walls so that air may circulate freely around it. The receptacle 50 has a cover 52 held in place by snap clamps 53 and the cover member 52 is provided with a vent pipe 54 surrounded by a rubber or the like sealing member 55. It will be clear from a consideration of Figures 6 and 7 that when the receptacle 50 has been loaded with Dry Ice and is slipped into the chamber 41, the vent pipe 54 telescopes into the vent pipe 18 which is of larger diameter and the edge of the pipe 18 compresses the sealing chamber 55 so as to provide a sealed vent for the receptacle 50 to the outside air. A handle member 56 is provided for the member 50 for convenience in handling.

The vent structure just described is necessary because the Dry Ice, as it absorbs heat, vaporizes and the vaporized carbon dioxide must be vented to the atmosphere. It will be understood that for installation in airplanes or the like the vent pipe 18 may be connected to a pipe which is vented to the outside of the fuselage.

Since in a box as described above there is no compressor which can be started or stopped in accordance with refrigeration requirements, means must be provided to control the temperature within the chamber 32. This is accomplished by means of a valve adapted to cover the aperture 34 in the shelf 30 and which is thermostatically actuated. The thermostat is arranged so that it may be placed on either one of two settings in one of which it will maintain a temperature suitable for frozen foods, as for example between --5 F. and -10 F. and in the other of which it will maintain a temperature 4 suitable for the storage of non-frozen foods, say between 35 F. and 45 F.

The valve and thermostat and associated parts will now be described with reference to Figures 8 to ll inclusive.

Secured to the bottom of the shelf `30 by means of screws or the like is a plate 60 having a hole 60a. A bracket 61 mounted on the plate 60 provides bearings for the valve rock shaft 62. The valve proper is indicated at 63 and a counterweight is indicated at 64. The rocker arm 65, to which the valve 63 and the counterweight 64 are attached, may be in the form of a piece of sheet metal suitably formed as shown and it is provided with a hole 66 through which the actuating rod 67 may be attached. The other end of the actuating arm 67 is attached to the end of a coiled birnetallic element 68.

The adjusting mechanism comprises a first plate 70 having a hole 70a, and provided with the arcuate slots 71. A headed screw 73 passes through one of the slots 71 and is screwed into the plate 60 and a thumb screw 74 passes through the other slot and is threaded into the plate 60. The screw 73 simply serves as a retainer and the thumb screw 74 serves to clamp the plate 70 in adjusted position. A ring or bushing, which may be of aluminum, is indicated at 90. The ring 90 is pressed into the hole 60a, and engages in the hole 70a, serving as a bearing for the plate 70.

The second plate, 80, is provided with the arcuate slots 83 and headed screws 84 pass through the slots 83 and are threaded into the plate 70. The stud 72 (Figure ll) has a ange 72a, and it is slotted at 82 and drilled and tapped axially at 81. The stud 72 is assembled to the plate by means of a screw 82a passing through the washer 81a, the plate 80 and into the hole 81 in the stud 72. The inner end of the bimetallic element 68 is secured to the slot 82 of the member 81.

It will be understood that when the plate 80 is clamped to the plate 70 by means of the screws 84, the setting of the thermostat can be changed by loosening the thumb screw 74 and rotating the plate 70 and its associated parts by means of the finger tab 86. Moving the tab in an upwardly direction, as seen in Figure 9, will provide for a colder temperature in the chamber 32, while moving the tab downwardly will provide for warmer temperature in the chamber 32.

In the initial setup, the stud 72 is adjusted by loosening the screw 82a and turning it, until the end of the bimetallic element is in approximately correct position with respect to the actuating rod 67 and then tightening the screw 82a. Once this adjustment is accomplished, it is desirable to lock the stud 72 to the plate 80. This is accomplished by drilling and tapping a small hole through the washer 81a, plate 80 and ange 72a, and inserting a small screw as at 91.

The plate 70 is then rotated counterclockwise, as seen in Figure 9, until the screws 73 and 74 engage in the ends of the slots 71. The screws 84 are then loosened and the plate 80 is adjusted by means of the finger tab 86 until the desired freezing temperature is attained. The screws 84 are then tightened to clamp the plate 80 to the plate 70 permanently. To insure a permanent adjustment, small holes may be drilled and tapped into the plate 70 at ends of the slots 83, and small screws inserted as at 92. It will by clear that the screws 92 will prevent accidental movement of plate 80 with respect to plate 70 even if the screws 84 become loose.

The unit is then moved by means of the tab 85 in a clockwise direction and adjusted until the desired normal refrigerating temperature is achieved and at that point a pin 87 is inserted through one of the slots 71 (preferably the innermost one of these slots) and screwed into the plate 60 to detine the other limit of movement of the plate 70.

When the unit has been thus adjusted, all that is necessary to shift Yfrom one `temperature to theother is to loosen the thumb screw 74 and' move the plate 70 by means .ofits iinger tab 85. Thepredetermined two ternperatures will-be achieved at the two extremities of movemeut of the plate 70.

yFrom what has been said above, it will be clear that if the temperature in the chamber 32 increases so that a greater flow of -cold air is required, the bimetallic element pulls on the rod 67 :opening v,the valve `63 and that when the required low temperature is attained, the bimetallic element 68 moving in the opposite direction closes the valve 63.

It will be clear that numerous variations and modiications may be made without departing from the spirit of my invention and I therefore do not intend to limit myself in any manner other than as set forth in the claims which follow.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A refrigerator comprising an insulated box having a door, a horizontally disposed insulated shelf dividing said box into an upper refrigerant compartment and a lower refrigerated chamber, said shelf being shorter than the depth `of said box to provide a clearance between the front of said shelf and the inside of said door, and having an aperture adjacent the rear of said shelf, a valve for closing said aperture, a thermostat for actuating said valve disposed in said chamber, a bafe disposed in said chamber in operative relation to said aperture to direct air flowing from said aperture toward the rear of said chamber, a supplementary insulated door for said compartment spaced from the top of said compartment, and a refrigerating medium in said compartment, whereby cold air flows from said compartment through said aperture into said chamber toward the rear wall thereof, and thence upward and forward between said door and snpplementary door, and over said supplementary door back into said compartment, by convection, as controlled 'oy said thermostatically actuated valve.

2. A refrigerator according to claim l, wherein the refrigerating medium is solid carbon dioxide, said medium being contained in a closed container having a vent opening and adapted to it in said compartment, said compartment having a vent pipe adapted to register with said vent opening when said container is disposed in said compartment, to vent said container to the outside atmosphere.

3. A refrigerator according to claim l, wherein the refrigerating medium is solid carbon dioxide, said medium being contained in a closed container having a vent opening and adapted to fit with clearance on all sides within said compartment, spacing elements for maintaining said container in spaced relation to the walls of said compartment and said supplementary door, said compartment having a vent pipe adapted to register with said vent opening when said container is disposed in said compartment, to vent said container to the outside atmosphere.

4. A refrigerator according to claim l, wherein the refrigerating medium is solid carbon dioxide, said medium being contained in a closed container having a stub vent pipe and a compressible sealing member surrounding said stub vent pipe, said container adapted to iit in said compartment, said compartment having a vent pipe having an internal diameter larger than said stub vent pipe and telescoping over the latter and into sealing engagement with said sealing member when said container is disposed in said compartment, to vent said container to the outside atmosphere.

5. A refrigerator according to claim l, wherein the refrigerating medium is solid carbon dioxide, said medium being contained in a closed container having a stub vent pipe and a compressible sealing member surrounding said stub vent pipe, said container adapted to tit with a clearance on all sides within said compartment,

spacing elementsfor maintaining said container inspaced relation to the walls of said compartment and said -supplementary door, said compartment having a vent l'pipe having an internal diameter Vlarger than said stub vent pipe and telescoping -over the latter and into sealing engagement with said sealing member when said-container i-s disposed in said compartment, to vent said container to the outside atmosphere.

6. A refrigerator comprising an insulated box having a door, a horizontally disposed insulated shelf dividing said box into an upper refrigerant compartment and a lower refrigerated chamber, said shelf being shorter than the depth of said box to provide a clearance between the front of said shelf and the inside of said door, and having an aperture adjacent the rear of said shelf, a valve for closing -said aperture, a thermostat for actuating said valve disposed in said chamber, a bafe disposed in said chamber in operative relation to said aper ture to direct air flowing from said aperture toward the rear of said chamber, a supplementary insulated door for said compartment spaced from the top of said compartment, and a refrigerating medium in said compartment, whereby cold air flows from said compartment through said aperture into said chamber toward the rear wall thereof, and thence upward and forward between said door and supplementary door, and over said supplementary door back into said compartment, by convection, as controlled by said thermostatically actuated valve, said thermostat comprising a base plate secured to the underside of said insulated shelf, a main adjusting plate pivotable on said base plate over a limited range, an auxiliary adjusting plate pivotable with respect to said main plate over a limited range, means for securing said auxiliary plate to said main plate in a desired. position of adjustment, and a stud pivotable with respect to said auxiliary plate and capable of being secured in an adjusted position to said auxiliary plate, whereby when said main plate is pivoted, -said auxiliary plate and stud are pivoted also, means for clamping said main plate in a desired position of adjustment, a heat responsive element secured to said stud, and an operative connection between the free end of said heat responsive element and said valve.

7. A structure according to claim 6, wherein said main adjusting plate is provided with an arcuate slot on a radius about the axis of said stud and a screw passes through said slot and is threaded into said base plate for clamping said main adjusting plate in adjusted position and wherein said auxiliary adjusting plate has an arcuate slot on a radius about the axis of said stud and a screw passes through said last named arcuate slot and is threaded into said main adjusting plate for :clamping said auxiliary plate to said main plate in a desired position of adjustment.

8. A two-temperature thermostatically actuated valve comprising a base plate, a main adjusting plate pivotable with respect to said base plate over a limited range, an auxiliary adjusting plate pivotable with respect to said main plate over a limited range, means for securingv said auxiliary plate to said main plate in a desired position of adjustment, and a stud pivotable with respect to said auxiliary plate and capable of being secured to said auxr iliary plate in an adjusted position, whereby when said main plate is pivoted, said auxiliary plate and stud are pivoted also, means for clamping said main plate in a desired position of adjustment, a heat responsive element secured to said stud, and an operative connection between the free end of said heat responsive element and said valve.

9. A structure according to claim 8, wherein said heat responsive element is a coiled bimetallic element.

10. A structure according to claim 8, wherein said main and auxiliary adjusting plates are provided with arcuate slots on a radius about the axis of said stud, a screw passing through the arcuate slot in said main plate and threaded into said base plate for clamping said main plate in a desired position of adjustment, `a screw passing through the arcuate slot in said auxiliary plate and threaded into said main plate to clamp said auxiliary plate in the desired position of adjustment with respect to said main plate.

References Cited in the tile of this patent UNITED STATES PATENTS Rowledge Feb. 9, 1932 Rice Feb. 26, 1935 Gilpin Feb. 9, 1937 Atchison Aug. 4, 1942 FOREIGN PATENTS Great Britain Feb. 7, 1949

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