Refrigerator

Nov. 8, 1938.

2,136,222

R. H. STARR

REFRIGERATOR

Filed Feb. 20, 1935

<img file="US2136222A_D0001.tif" />

Patented Nov. 8, 1938

2,136,222

UNITED STATES PATENT OFFICE

2,136,222 REFRIGERATOR Raymond H. Starr, Kansas City, Mo. Application February 20, 1935, Serial No. 7,363 5 Claims. (Cl. 62—103)

This invention relates to refrigerators and particularly to those of that character wherein condensation from the refrigerating elements is caught by drip pans that are supported over the 5 merchandise undergoing refrigeration. In refrigerators of this character, the drip pans not only interfere with circulation of air around the refrigerating elements, but they form surfaces on which moisture in the air condenses and 10 drips therefrom onto the merchandise.

It is, therefore, the principal object of the present invention to provide a refrigerating element and drip pan construction which promotes circulation of air and prevents condensation on the 13 under surface of the pan.

In accomplishing this and other objects of the invention, as hereinafter pointed out, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying 2Q drawing, wherein:

Fig. 1 is a cross sectional view through a display type refrigerator equipped with refrigerating elements and drip pans embodying the features of the present invention.

Fig. 2 Is an enlarged cross section through one ²⁵ of the refrigerating elements and the drip pan associated therewith.

Fig. 3 is a detail perspective view of one end of the refrigerating elements particularly illustrating their relation to the drip pans which ³⁰ collect water resulting from defrosting of the refrigerating elements.

Fig. 4 is a fragmentary vertical section through one of the refrigerating elements and drip pans ... supported thereunder.

’Fig. 5 is an enlarged perspective view of a portion of one of the drip pans particularly illustrating. its construction whereby condensation in the bottom of the pan is prevented.

₄₀ Referring more in detail to the drawing:

I designates a conventional refrigerator^- display case including front and rear walls 2 and 3 connected by top and bottom walls 4 and 5 and end walls 6 to form a longitudinal refrigerating compartment 7. Supported in the refrigerating ° compartment is a plurality of superimposed shelves 8 and 8' upon which merchandise is placed for display through transparent panels 9 that are incorporated into the front wall 3. Access is had ₅₀ to the display on the shelves through openings 10 provided in the rear wall 2 and closed by doors 1 I. In display refrigerators of this character, refrigerating elements 12 are Usually located in the top of the compartment 7 and over the mer55 chandise on display in order to provide natural gravitational movement of the cold air downwardly, from the relatively cold temperature surrounding the refrigerating elements and over the relatively warmer merchandise on the shelves and 60 movement of relatively warm air surrounding the merchandise upwardly for circulation around the refrigerating elements.

It is well known that moisture content of the merchandise on display is absorbed by the air and deposited on the refrigerating elements in ₅the form of frost which is added to by accumulations caused by moisture laden air being carried into the refrigerating compartments upon opening of the doors i I.

This frost accumulates to such an extent that ₁₀it interferes with efficiency of the refrigerating elements and it is necessary to defrost the coils at frequent periods. When defrosting the refrigerating elements, the ice melts and drips therefrom in the direction of .the merchandise but is _lgcaught in a drip pan that is supported below the refrigerating elements.

This construction takes care of the moisture from the refrigerating elements but due to the size and relatively low conductivity of the pans, ₂₀they tend to retain low temperatures and are slow to conform to air temperatures within the case. Consequently, air contacting the under surface of the pans reaches the dew point and, therefore, condenses thereon and drips onto the merchandise. ' 25

I, therefore, provide an arrangement of refrigerating elements whereby the areas from which the melting ice drips are limited to a small portion of the refrigerating surfaces. The size of the drip pans can thus be reduced to that suffi- ³⁰cient to catch the water, thereby not only promoting circulation of air about the refrigerating elements but reducing the thermal capacity of the pan so that the temperature of the pan is quicker to respond to the temperature of the air. ³⁵Consequently, the air does not as quickly reach the dew point when moving in contact with the pan.

Opposite faces of the pan have different capaci- ties for absorbing radiant energy; that face which ^4Gfaces the refrigerating element is bright, while the other face is darkened. Thus the temperature of the pan itself will be warmer than if both faces have equal capacities for absorbing radiant energy. 45

In the illustrated instance, the refrigerating elements 12 are arranged in pairs designated 13 and 14 and extend longitudinally of the compartment, each element comprising interconnected pipes 15 arranged in the form of a hollow ⁵⁰square with its diagonal axes in perpendicular and horizontal planes so that the radiating fins 16 thereon are positioned with the lower corners 17 thereof located in the perpendicular plane. _ggBy thus locating the fins, moisture melting from the pipes gravitates downwardly over the faces of the fins and along the lower converging edges 18 and 19 thereof to the corners 17, from where it drips into the drip pans above mentioned, eo

2,136,222

With this arrangement of the coils, it is clearly obvious that a drip pan need be provided of only sufficient width to catch the water dripping from the corners IT.

In order to insure that the water does not drip from the edges 18 and 19, the fins are preferably spaced close enough upon the pipes 15 so that the capillary action afforded by the spaces therebetween is sufficient to retain the flowing 10 water in contact therewith until it reaches the points IT.

The drip pans 20 and 21 for the respective refrigerating sections are formed in the shape of troughs sloping from one end of the compart15 ment to the other where they empty into a collection pan 22 having an opening 23 in one corner thereof connected with a waste pipe 24 leading to a sewer or other place of disposal.

For convenience of construction, the troughs 20 20 and 21 are preferably formed of strips of sheet metal bent on their longitudinal centers to provide valleys 25 and upwardly diverging sides 26 and 27 spaced apart a sufficient distance to assure collection of the water dripping from the 25 fins Π.

In order to stiffen the troughs and enhance the appearance of the upper edges thereof, they are preferably flanged inwardly and then downwardly to lie against the inner faces of the 30 troughs as indicated at 28. The pan 22 is also constructed of sheet metal and has flaring sides 29 conforming to the side flanges of the troughs as best illustrated in Fig. 3.

In order to further reduce the thermal ca35 pacity of the troughs and pan 22, they are preferably constructed of a metal having high thermal conductivity such as for example aluminium or an aluminium alloy of extremely light gauge.

By thus constructing the pans, the high ther40 mal conductivity thereof causes the temperature of the pans to more quickly assume the temperature of the air circulating thereunder and substantially relieves the fins of condensation on the under surfaces thereof. I have found, 45 however, that by treating the under surfaces of the pans with a dark coating having heat absorbing properties as indicated at 30, the metal quickly absorbs and retains heat radiated from the merchandise on display so that the tempera50 ture of the pan tends to approach that of the merchandise.

I have also found that by providing the pan with a bright or polished upper surface, as indicated at 31, the radiant energy absorbing ca55 pacity thereof is greatly reduced and radiation of the heat absorbed through the lower heat absorbing face is inhibited in the direction of the cooling coil, the temperature of the coil, therefore, has less effect on the pan, and I am 60 enabled to additionally raise the temperature thereof.

The troughs are preferably supported under the respective cooling elements by means of hooks 32 engaging the lowermost pipe 15 and 05 having their lower ends connected to cross bars 33 extending transversely of the troughs in spaced relation to the bottom thereof.

For example, assuming that the temperature surrounding the coils which may be termed a 70 cold body is 30° and the merchandise which may be termed a warm body is maintained at a temperature of 40° the temperature of the drip pan can be maintained at a constant temperature of 38° which is more nearly that of the 75 merchandise and is high enough to prevent air moving thereover from reaching the dew point. The maintenance of this temperature also has the advantage in that it prevents formation of ice in the pans that would cause them to overflow when the refrigerating elements are de- 5 frosted.

It is also possible to maintain the pans in relatively dry condition because the water does not freeze therein, but readily drains therefrom into the collecting pan and from there into the 10 disposal pipe 24.

The drip pans also provide means for controlling air circulation about the cooling elements. For example, when warm merchandise is placed on the shelves, heat radiating therefrom 15 is absorbed by the coating 30 to raise the temperature of the pans to approximately that of the merchandise. Upon heating of the pans, the air circulating thereabout becomes warmer and results in increased circulation about the cooling 20 elements. As the merchandise cools off, the heat radiation therefrom decreases and the pans cool off in the same proportion to correspondingly reduce air circulation about the cooling coils.

From the foregoing it is apparent that I have 25 provided a coil arrangement and pan construction which prevents condensation on the under side of the pan that ordinarily drips upon the merchandise on display.

By maintaining the pan at a temperature sub- 30 stantially that of the air moving thereacross, the pan is maintained in relatively dry and sanitary condition.

It is also obvious that since the pan is only of sufficient width to catch the moisture dripping 35 from the coils, it does not interfere with circulation about the refrigerating elements, but due to the high temperature thereof, the circulation about the cooling elements is increased.