US2082756A - Refrigeration apparatus - Google Patents

Description

June 1, 1937. E. s. PRIDHAM REFRIGERATION APPARATUS Original Filed May 51, 1932 illlliilllllfllllllllllil!!! INVENTOR, EDWIN s. P/P/DHAM.

A TTORNE Y Patented June 1, 1937 2 032 755.

UNITED STATES PATENT OFFICE Edwin S. Pridham, Oakland, Calif.

Application May 31, 1932, Serial No. 614,322 Renewed January 15, 1935 5 Claims. (01. 62-90) y invention at s to r f i atin appachanger. Heat transference from the liquid in ratus, and more specifically to such apparatus in the circulating system is rapid due to the use of which evaporation of a fluid at atmospheric presmetals having good heat conductivity in the heat sure produces the cooling effect. exchanger.

5 Among the objects of my invention are: To In Figure 1 a circulating system I, preferably provide a system in which an efficient loss of heat built up from pipe, has a cooling coil section 2, W111 occur; o p v m n for provi ing a large and a heat exchange section 4. This forms a area of evaporating surface; to provide a circuclosed system and is filled with a liquid, preferlating refrigerating system in which the heat exably water or brine. The cooling coil is conchanger and cooler are separate units; and to tained in a refrigerator box 5, which is provided 10 provide a refrigeration system which is simple in with a removable top cover 6. While I have construction, economical to'manufacture, durable shown a top opening box, it will be apparent that and efficient in use, and which permits of atthe cooling coil may be so arranged inside the taining a low, humidity in the interior of the box that a side door can be used. The refrigerrefrigerator box. ator box is preferably double walled and the space 15 Other objects of my invention will be apparent between the walls filled with a good heat inor will be specifically pointed out in the descripsulator such as ground cork or asbestos wool. Box tion forming a part of this specification, but I legs l'serve to raise the cooling chamber from do not limit myself to the embodiment of my inthe floor.

vention herein described, as various forms may The heat exchange portion of the system is L0 be adopted within the scope of the claims. preferably a casting of a metal having high Referring to the drawing: heat conductivity such as copper or aluminum,

Figure 1 is a longitudinal sectional view of a and is preferably provided with integral fins 9 preferred type of my refrigeration system. as shown in Figure 2. The center of the heat ex- Figure 2 is a cross sectional view through the changer is preferably bored out to form an inte- 25 heat exchanger shown in Figure l on the line rior straight and smooth tube l0. Couplings ll v and elbows l2 serve to connect this straight por- Figure 3 is a longitudinal sectional view of the tion to the system I. Unions [4 are provided so top portion of an alternative form of heat exthat the two units may be easily disconnected if changer. desired. 30

Figure 4 is a crosssectional view of the heat An alternative form of heat exchanger is exchanger as shown in Figure 3, and taken on shown in Figure 4', and here thecentral bore is the line 4-4. connected to the hollow fins l5; These fins are The principle upon which the invention is provided with seepage holes 16 of small diameter based is that of cooling by the evaporation of at extending through the fin "walls and connecting volatile fiuid. The degree of cooling will be dethe interior of the heat exchanger with the outpendent upon the difference in temperature beside. f tween the wet and dry bulb thermometers, and In both forms of heat exchangers the fins are the device will be most efficient in hot dry clicovered with absorbent fabric H such as coarse 40 mates, where a cooler is most desirable. Crude linen, burlap or canvas. When solid fins are used 40 forms of coolers using the above principle are holes I9 are preferably provided in the fin strucexemplified by the porous Mexican ollas for coolture to permit air circulation through the fabing water, and the wet burlap mountain type ric. cooler which is well known in the art. The entire heat exchanger is surrounded by a Broadly speaking my inventionv comprises a casing 20 which not only supports the structure, 45 circulating liquid refrigeration system which is but acts as a flue to confine air to the space ocdivided into two portions. One portion is on the cupied by the heat exchanger. The bottom porinterior of a chamber to be cooled, and the tion 2| of this casing is preferably formed into other portion is a heat exchanger. This portion a cone shape and provided with a drain pipe 22 of the system is provided with a convoluted surto carry off accumulated unevaporated fluid. 50 face covered with fiuid absorbent material and The bottom portion 2| of the casing may be this material kept saturated with a volatile fluid. solid as shown, and air supplied to the casing by The fluid is then evaporated rapidly by causing blower 24, or, it may be perforated, and the draft a current of air to move past the absorbed fluid of air created through the casing by chimney in the fabric on the convolutions of the heat exaction. 55

A tank 25 smaller in diameter than the casing, is supported on the top of the casing 20 by brackets 26, and the bottom of the tank is perforated with small drip holes 21. A supply of volatile liquid, preferably water, on account of its availability and cheapness, is provided by a faucet 28 in connection with the water main 29.

When the hollow fin form is used as shown in Figure 4, the tank 25 is not perforated, but is connected directly to the circulating system as shown at 30. This allows water from the tank to supply the loss of water through theseepage holes I 6 in the walls of the hollow fins I 5.

Casing 20 and cooperating structures are mounted on casing legs 3| which serve to rais the heat exchange structures off the floor.

In operation water is admitted to the tank and drips onto the fabric mounted on the fins, and is absorbed by the fabric. The air moved through the casing either by draft or by the blower as shown, evaporates the absorbed water and the temperature of the fabric is reduced to that'of the wet bulb thermometer. This fabric being in intimate contact with a good heat conductor, cools the fins, and also abstracts heat from the water or brine in the system. The

liquid thus cooled becomes heavier than that in theuncooled portion of the system and a circulation will be started through the exchanger downward and into the cooling chamber. Here the liquid will pick up heat from the articles inside, and'the liquid thus warmed will rise to the top of the cooling coil and pass back to the top of the heat exchanger, thereby creatf ing a continuous circulation of liquid in the system. V The drip of water from the tank is preferably adjusted to cover the fabric on the entire surface of the fins, and to supply just enough to allow for the evaporation.

In the hollow fin type of heat exchanger water from the system will seep through the holes in the fin walls and saturate the fabric. The pressure in the supply tank may then be regulated to supply just enough water to the fabric.

While the temperaturev drop is dependent on the difference, betweenthe wet and dry bulb readings of the thermometer, the amount of space than can be lowered to the wet bulb temperature will depend on the area of evaporative surface. AIarge space may be cooled by my invention with a, small heat exchanger because of the rapid evaporation and efficient heat transfer.

While the preferred form of my invention shows a blower to movethe air, it will be obvius that in localities where power is not avail- ,refrigeration system able, any of the known may be used, such as flue ing of funnels facing the as are used on ship board.

As an example, with an air temperature of with a humidity of 30 per cent, the temperature of the refrigerator box may be reduced 20 and even lower with lower humidities.

I claim:

1. A heat exchanger for a circulating refrigeration system which comprises a tube of high heat conducting material, a fin integral with said tube, a layer of fluid absorbent material on said fin, said fin having ducts connecting said tube with said fluid absorbent material.

2. A' heat exchanger for a, circulating liquid which comprises a conduit of high heat conductivity, fins integral with said conduit extending longitudinally along said conduit, a layer of fluid absorbent material on said fins, means for supplying a volatile fluid to said material, an enclosure for said conduit and fins, and means for passing a current of air through said enclosure and between said fins in a direction opposite to the circulation of liquid in said refrigeration system.

3. In combination with a circulating fluid refrigeration system, a heat exchanger comprising a tubular conduit for said fluid, fins on said conduit, said conduit and said fins being formed of a metal having a high heat conductivity, a fluid absorbent material on the outer surface of said fins, said fins having apertures therein for conveying said fluid to said fluid absorbent material.

4. In combination with a circulating fluid refrigeration system, a heat exchanger comprising a tubular conduit for said fluid having a smooth interior duct and a corrugated external surface, said conduit being formed of a, metal having high heat conductivity, a layer of liquid absorbent material on said corrugated surface, and means for cooling said conduit by the evaporation of a volatile fluid from said liquid absorbent material.

5. A heat exchanger for a circulating refrigeration system which comprises a tube of aluminum, an aluminum fin integral with said tube, a layer of fabric on said fin, said fin having ducts connecting the interior of said tube with said fluid-absorbent material, and means for passing a current of air through said fin to evaporate fluid therefrom, said ducts being of a size sufficient to supply fluid from the interior of means of moving air action, or the providprevailing wind such the tube to said fabric at a rate at least equal I to the evaporation rate.

- EDWIN S. PRIDHAM.

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