US2044600A

US2044600A - Refrigerating apparatus

Info

Publication number: US2044600A
Application number: US548612A
Authority: US
Inventors: Harry M Williams
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1931-07-03
Filing date: 1931-07-03
Publication date: 1936-06-16
Anticipated expiration: 1953-06-16

Description

June 16, 1936. H. M. WILLIAMS 2,044,600

REFRIGERATING APPARATUS I Filed July s, 1931 AEYs Patented June 16, 1936 mesne assignments, to General Motors Corporation, a corporation of Delaware Application July 3, 1931, Serial No. 548,612

6Claims.

This invention relates tor'efrigerating appara tus and more particularly to refrigerator cabinets having insulating walls formed of a, plurality of spaced sheets of bright metallic foil.

In insulation of spaced sheets of bright metallic foil, the enclosed air spaces are provided for preventing the transmission of heat by conduction, and the sheets of bright metallic foil are provided for preventing the transmission of heat by radiation. The bright metallic foil accomplishes this by its reiiecting qualities. Hence in order to preserve the reflecting qualitiesA of this bright metallic foil, it is essential that this foil should not tarnish. I 'I'his tarnishing is ordinarily .caused by the condensation of moisture uponthe foil which usually enters the insulation carried by external air which finds its way therein.

The objects of my invention include the provision of means for preventing thebright metallic foil from tarnishing, the provision of means for preventing the access of external air to the foil insulation and for preventing the condensation of moisture upon the foil.

Further objects and advantages of the present invention will be apparent from the following description, reference being hadto the accompanying drawing, wherein a preferred form of the present invention is` clearly shown.

In .the drawing: l

Fig. 1 is a vertical sectional view oi a refrigerator embodying the invention;

Fig.2 is an enlarged sectional'viewof a portion of Fig. 1, and

Fig. 3 is an enlarged sectional view of another portion of Fig. l.

In Fig. l there is shown a refrigerator cabinet 20 having a. machinery compartment 2| in ,the lower portionand a food storagel compartment 22 in the upper portion of the cabinet.

Pillars

23 and 24 in the corners of the machinery compartment support the walls of the-food storage compartment. The food storage compartment has an innerwall or shell 25 of sheet metal, preferably covered with a suitable substance such as porcelain, and an outer metal wall or shell 26- preferably covered with porcelain; paint, lacquer or other suitable substance. A door 21 is provided in one wall of the food storage compartment and has on its inner side a sheet metal member- 28, coated with porcelain, and on its outer'oide.rr

(Cl. (i2-89) at the four corners of the machinery compartmeut 2|. A cooling unit 30 of any suitable type containing a volatile refrigerant is supported by the top wall of the inner wall or shell 25 within the food storage compartment. Evaporation of refrigerant within the cooling unit maintains the cooling unit 30' at a. low temperature and cools the-cabinet by the convection of air within the food storage compartment.

In order to prevent the porcelain coating upon the exterior of the refrigerator cabinet from chipping, a chip board 3| is placed against the inner side of the outer sheet metal walls 26. By preventing excessive flexing of the outer sheet metal walls, the chip board prevents the porcelain from-chipping. nInside of the outer sheet Vmetal wall 26 and the chip board 3|, a relatively thin layer of insulating material 32 of the fibrous type such as cork is. provided. This insulating material 32 reduces the amount of heat transl mitted by conduction. Between the insulating material 32 and the inner sheet metal shell 25 are provided a plurality of spaced sheets of bright metallic foil. These sheets of foil 33 are spaced by wooden frame members 36 to provide air spaces between the sheets of foil. The air spaces between the sheets ofV foil further reduce the transmission of heat by conduction and the sheets of bright metallic foil reduce the amount of heat transmitted by radiation to a minimum. By such a.construction' the amount of h'eat leakage'into ,the cabinet is exceedingly small. If desired, an additional sheet of foil separated by air spaces from the other sheets of foil and the chip board 3|', may beused instead of the fiber insulation 32. In order to preserve the reflecting qualities of the bright metallic foil so as to prevent heat leakage byvradiation, it is necessary to prevent the tarnishing of the bright metallic foil. This tarnishing has its source in thelleakage of warm` air from theoutside of the cabinet to the insulation between the inner and

outer shell

25 and 26. The cause of this warm air getting into the insulation is due to the fact that it is practically impossible to perfectly seal the insulation,` and that because of the varying temperature of the walls of the cooling unit and the varying barometrlc pressure, due to changing weather conditions, the, air from the exterior of the cabinet is alternately drawn in and forced out-of spaces between the r outer-and inner shells 25' and 26. inasmuch as f theinner shell 25 is made in one piece, leakage of air from the interior of the cabinet to the insulation does not often occur, consequently the air by these causes is ordinarily drawn from.

'uration point and normally contains a large amount of moisture as compared to the cold air within the cabinet. When this warm air reaches the insulatiomit is cooled because of the coldness within the -cabinet and by this cooling the saturation point, that is, the capacity of the air for holding the moisture, is reduced so that dew or moisture is condensed or deposited in and on the insulation. Thisedew lowers the insulating value of the brous type of insulation and causes the bright metallic foil of the foil type of insulation to tarnish and become dull so that its reflecting properties are diminished.

As stated above, the air within the food storage compartment 22 contains a relatively small amount of water vapor therein since the air in its circulation past the cooling unit has been reduced in temperature so that the excess moisture in the air has been condensed out oi' the air and as a result, the air contains only a small amount of water vapor therein. By the breathe ing action of the insulation, I supply ,this cold air containing a relatively small amount of water vapor through the breathing tube to the insulation between the inner and

outershells

25 and 26. The tube 35 has its mouth preferably directly beneath the cooling unit so as to draw the coldest air inside of the food storage compartment. Apertures 3G and 31 are provided in the sheets of metal foil 33 to provide for the access of air between all the layers of insulation to the tube 35. The spacing members 3l are also provided with apertures 38 for providing access of air from the various side panels of the cabinet to the breathing tube 35. In order to further prevent a tarnishing of the foil, extremely thin coating of beeswax or stearic acid may be applied. Preferably, however, the foil is provided with a thin plating of chromium which resists tarnishing to a very high degree. Chromium plated foil resists tarnishing to such a degree that it may be used for insulation without the above described breathing apparatus. Instead of ordinary foil, sheets of paper coated with a suitable adhesive which in turn is coated with aluminum lining bronze by a dusting method may be used.

' The door 21 is similarly insulated. The door 21 is provided with a thin layer l0 of insulating material of the brous type and a plurality of layers of bright metallic foil Il suitably spaced by spacing members 42 of wood or other suitable material. The sheets of foil are provided with apertures I3 which provide access; of the air between the layers of foil to a breathing tube 44 which extends beneath the cooling unit. Inasmuch as the zone immediately beneath thecooling unit contains air which has just been cooled by the cooling unit, it is preferable that the breathing tubes should havegtheir mouths immediately beneath the cooling unit. The foil in the door may be treated similar to the foil in the other parts of the cabinet as described bovelto prevent tarnishing.`

Thus I have disclosed means for preventing sheets.of bright metallic foil from tarnishing.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form,

it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as folltws:

1. A refrigerator including a cabinet having inner and outer walls, a cooling unit supported within said cabinet, insulation between said inner and outer walls, said insulation comprising a plurality of spaced sheets of bright metallic foil, and means for preventing said foil from tarnishing including breathing means having connections with the spaces between said sheets for inhaling into said spaces only air dehydrated by .Said cooling unit.

2. A refrigerator including a cabinet having 15 inner and outer walls,` a cooling unit supported within said cabinet, insulation between said inner and outer walls, said insulation comprising a plurality of spaced sheets of bright metallic foil,

and means for preventing said foil from tarnish` 20 ing including breathing means having a tube structure connecting with the spaces between said sheets, said tube structure extending immediately beneath the cooling unit i'or inhaling into said spaces only air dehydrated by said cooling unit. 25

3. A refrigerator including a cabinet having inner and outer walls. and insulation -between said inner and outer walls comprising a plurality of spacingxmembers, a plurality of sheets of foil mounted `in-'spaced relation upon the spacing 30 members forming insulation spaces, said spacing members having passages therethrough and said sheets having passages therethrough providing a restricted communication between the insulation spaces, and breathing means having a single 35 passage communicating with the interior of the cabinet and said communicating insulation spaces for inhaling into said spaces only'cold dry air from the interior of the cabinet.

4. An insulating structure including inner and l outer walls and insulation between the inner and Outer walls including a plurality oi' sheets held in spaced relation by structural members prviding substantially dead air spaces between the sheets at least some of the sheets having bright 45 metal surfaces, and breathing means for breathing air into and from the air spaces.

5. An insulating structure including inner and outer walls and insulation between the inner and outer walls including a plurality of sheets o! bright metal i'oil held in spaced relation by structural members providing substantially dead air spaces between Ythe sheets of foil, and breathing means communicating with each of the air spaces" 5,' between the sheets of bright metal i'oilfor breathing air into and from the air spaces aforesaid. 6. An insulating structure including an-enc1o sure formed of spaced inner and outer walls, in-

sulating means between said spaced inner and -outer walls including a plurality oi' sheets held in spaced relation by structural members providing substantially dead air spaces between the sheets, at least some of the sheets having heat reflecting surfaces, said inner walls being provided an with breathing means for breathing air from the interior of the enclosure into the space between the inner and outer walls.