US1843913A - Refrigerating apparatus - Google Patents

Description

Feb. 9, 1932. v P-M, BRA-[TEN 1,843,913

REFRIGERATING APPARATUS Filed April 50, 1927 @www Patented Feb. 9, 1932 UNITED STATES PATENT y OFFICE PHILIP M. BRATTEN, OF FORT WORTH, TEXAS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO FRIGIDAIRE CORPORATION, A CORPORATION OF DELAWARE REFRIGERATING APPARATUS Application led Apri1 30,

This invention relates to mechanical refrigeration and particularly to mechanically refrigerating devices for cooling various type of commercial refrigerator cabinets such as show-case refrigerators.

One object of the invention is to improve the eliiciency of the transfer of heat from the circulating air of the cabinet to the metal walls of the refrigerating device by substantially preventing accumulation of frost thereon, and to improve the eliiciency of thermal transfer between the metal walls to the refrigerant, whereby refrigeration may be effected more eciently and economically than heretofore. In the present invention this object is accomplished by a novel arrangement of air flues and brine ducts to be described.

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

In the drawings:

Fig. 1 is vertical longitudinal sectional view of a show-case refrigerator cabinet equipped with a refrigerating device embodying the present invention;

Fig. 2 is a top view partly broken away, of the device; and f Fig. 3 is asectional view on the line 33 of Fig. 2.

In Fig. 1, 20 designates a cabinethaving solid insulating walls 21, 22 and 23 and other insulating walls provided by dead air spaces between a plurality of plates of glass 2 4 and 25. A partition 26 Adivides the interior of the cabinet into a cooling compartment 28 and a food or other display compartment 27.

The refrigerating device 30 includes a shell brine tank made of tin-plated copper or galvanized iron and formed to provide a. main brine chamber, reservoir or body portion 31 and a sheet metal shell or shells, the walls of which provide relatively large air flues 35, 36 and 37. These shell type walls are hollow to provide relatively narrow brine ducts or chambers 32, 33 and 34 which communicate with the body portion 3l.

1927. Serial No. 187,929.

The body portion or chamber 31 is provided with a tightly fitting removable cover 3S and encloses a cooling unit herein shown as an evaporator comprising a header or boiler 10 connected with refrigerant ducts 4l. One end of the boiler 40 extends through an opening 42 in the outside wall of the chamber 31 and is secured byl a flanged collar 43, a clamping disc 44 forming one end of the boiler, and by screws 45. Pipes 46 and 47 conduct refrigerant respectively into and out of the boiler 40. Thechamber and ducts should be filled with brine or other low freezing-point liquid up to about one inch below the top of the container and the boiler should not be located too low in the chamber 31, otherwise only the brine at the lower levels will effectively circulate and be cooled. Preferably the top of the boiler should vbe about one inch below the level of the brine.

It has been found that with a cooling unit located 10W in a deep tank, the brine above the unit does not cool down to the tem erature desired, it remaining above the reezing point even when the rest of the brine may be at or below freezing temperature.

The boiler 40 should beilevel in order that the float valve therein (not shown), which controls the flow of refrigerant to the unit, may operate properly. This is done by metal wedges 60 adapted to rest upon the bottom wall of the tank 31 and to engage the lower portions of the loop-ducts 4,1. The wedges 60 may be secured in the desired positiony by soldering. 'f

The device 30 is supported above the bottom of the cooling chamber 28 and is spaced from the chamber walls and baiiie 26 so that air lmay circulate freely around the device as well as through its flues. Preferably, the

combined surface of the exposed vertical walls of the device should at least be equal to the exposed surface of the block of ice which would be required to cool the cabinet. Bv providing relatively narrow brine ducts arid relatively large iiue openings, a relativemore than approximately two-thirds of the cubical content of the cooling chamber 28, and may be slightly less if necessary to provide at least three inches of space between the walls of the device and the cooling chamber walls so that air may circulate freely about and through the unit. The matter of clearance is important, because frosting of the tank and ducts tends to decrease the clearance and might even close it off entirely, preventing free circulation of the air. Unless the air can circulate freely adjacent the walls of the refrigerating device, it can not absorb the heat from the air. For the same reason the flue openings should be relatively wide.

The circulation of air within the cabinet is indicated roughly by the arrows 50, 51, 52 and 53. Shelves or other baffles (not shown) may be provided in the food chamber 27 for securing a fairly even distribution of the air circulating therein.

If more than one refrigerating device is used in a cooling chamber, at least four inches and preferably six inches should be left between the devices for circulation and to prevent the space from being stopped up with frost.

One of the features of the present invention is the use of such a relatively large metal, heat-absorbing surface adjacent which the air may circulate freely, that it is possible to effect satisfactory refrigeration by brine or other heat transfer medium working at temperatures higher than ermissible in brine tanks used heretofore. ing the active period of operation of the refrigerating machine frost may collect upon the metal surface, these surfaces will be defrosted during the idle periods of the machine. Thus hindrance by frost to the transfer of heat to the metal surfaces is much less than in case of brine tanks used heretofore.

Another feature is the circulation of brine through relatively narrow ducts between the metal, heat-absorbing surfaces. Substantially all of the brine which is cooled by the evaporator is caused to circulate actively so that heat will be conducted from the metal walls to the evaporator more rapidly than heretofore, with the result that the duration of the active period of the refrigerating machine is reduced.

It is therefore apparent that refrigeration can be obtained more economically than heretofore because the heat transferring media, the metal walls and the brine, are caused to o erate more efficiently, and because the mac ine is not required to reduce the pressure upon the refrigerant to the low point necessary heretofore, since the averagel brine temperature is higher.

I have discovered also that a cabinet can be cooled most effectively and economically 5 by mechanically refrigerated circulating brine when the refrigerating device containlthough, dur-A ing the brine occupies about two-thirds of the cubic capacity of the cooling compartment or chamber used formerly for receiving ice-blocks, and "when the ducts and lues of the unit are so constructed and arranged as to give the maximum cooling surface with the minimum brine. Large heat transfer surface results in reduction of the space required for` the cooling unit. Therefore, the compartment for receiving the device may be made smaller. Large fines permit free c irculation of air.

The refrigerating device may be provided with horizontal or vertical ues according to the type of refrigerator cabinet with which they are intended to be used. Vertical flues are preferable, owing to the natural tendency of air to descend on being chilled. However, the invention is not limited to refrigerating devices or tanks with vertical fiues, as a cooling unit with horizontal flues may be used advantageously in some types of cabinets; for example, a show-case cabinet not provided with a baffle to separate the food compartment from the cooling compartment.

Where the term brine is used in the specilicat-ion and claims, it refers to any low freezing point liquid or solution which is suitable for transferring heat from the heat transfer walls of the refrigerating device to the evaporator.

As an example of construction of one form of the invention, if the tank and ducts are made of sheet metal sufficiently thin to permit making the joints by lock-seaming and soldering, I prefer to provide ducts only one inch or less wide. If heavier sheet material is required on account of the size of the cooling unit, and the joints must therefore be riveted, the ducts may be tworinches wide to allow for introducing riveting tools between the metal sheets forming the ducts. There is no object in makinof the ducts wider than one inch except to facilitate manufacture. Generally, the brine ducts should be from about one to two inches wide and the fines preferably at least four times as wide as the ducts.

Vhile the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming vithm the scope of the claims which fol- What is claimed is as follows:

1. A cooling device for refrigerators comprising, a tank including a body portion adapted to contain brine, and a plurality of shell type hollow walls forming narrow circulating ducts communicating with the body portion, said walls providing one or more fines for circulating air, and a cooling unit within the body portion for cooling the brine.

2.-A cooling device for refrigerators comprising, a tank including a body portion adapted to contain brine, and a plurality of vertically extending shell type hollow walls forming narrow circulating ducts communieating with the body portion, said walls providing one or more vertically extending Hues for circulating air, and a cooling unit within the body portion for cooling the brine.

3. A cooling device for refrigerators comprising, a tank including a body portion` adapted to contain brine, and a plurality of shell type hollow walls forming narrow circulating ducts communicating with the body portion, said walls extending in a plurality of directions from the body portion and providing a plurality of Hues for circulating air, and a cooling unit within the bod portion for cooling the brine.

4. A cooling device for a refrigerator comprising a sheet metal shell forming a main chamber for brine, an evaporator' within the chamber for cooling the brine therein, certain walls of said shell being hollow and forming relatively narrow chambers, said narrower chambers branching from and communicating with the main brine chamber and arrangedto form a Hue for cooling circulating air.

5. A cooling device for a refrigerator com- Aprising a sheet metal shell forming a main chamber for brine, an evaporator within the chamber for cooling the brine therein, certain walls of said shell being hollow and forming relatively narrow chambers, said narrower chambers branching from and com'- municating with the main brine chamber, said hollow walls being arranged to provide a plurality of Hues, one of said walls be- 1ng common to a plurality of said Hues.

6. A cooling device for a refrigerator comprising a sheet metal shell forming a main chamber for brine, an evaporator within the chamber for cooling the brine therein, certain walls of said shell being hollow and forming relatively narrow' chambers, said narrower chambers branching from and communicating with the main brine chamber and arranged to form a Hue for cooling circulating `a1r, the cross sectional area ofthe refrigerating mediumvchambers formed by the hollowwalls being less than cross sectional area of the Hue formed by such walls.

rising a tank including a main brine cham.

er adapted to contain brine, and a plurality of shell type hollow walls forming narrow circulating ducts communicating with the main chamber, saidw walls extending in a plurality of directions from the chamber and providing ra Hue for circulating air, and aV cooling unit within the main chamber for cooling the brine.

9. A cooling device for refrigerators comprising a tank including a main brine chamber adapted to contain brine, and a plurality of shell type hollow walls forming narrow circulating ducts communicating with the main chamber, said walls providing one or more Hues for circulating air and a cooling unit within the main chamber for cooling the brine, the cro'ss sectional area of the circulating ducts formed by the hllow walls being less than the cross sectional area of the Hue formed by such Walls. l

In testimony whereof hereto ailix my signature.

PHILIP M. BRATTEN.

chamber for brine, an evaporator within the chamber for cooling the brine therein, certain walls of said shell being hollow and forming relatively narrow chambers, said narrower chambers branching from and communicating with the main brine chamber, said hollow walls being arranged to provide a plurality of Hues, one of said walls being common to a plurality of said Hues, the cross sectional area of therefrige'rating chambers formed by the hollow walls being less than i

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