US2095835A - Defrosting means for refrigerating apparatus - Google Patents

Description

Oct. 12, 1937. c. A. RODMAN DEFROSTING MEANS FOR REFRIGERATING APPARATUS Filed May 51, 1935 INVENTOR ATTORNEY Patented Oct, 12,1937

nnmos'rmq MEANS non arrm'ru Badman, Detroit, Mich, assignor to John B. Tanner Clarence A.

PATENT OFFICE.

gnramnmmc 'Aiipiicauon May 31, 1935, Serial No. 24,382

This invention relates to air conditioning and i refrigerating systems. Its' principal object is to provide a simple, effective means for quickly and economically defrosting the expansion or cooling 5 coils of such a system.

In the use of refrigerating means in the apparatus when forced circulation of air is provided, such for example as in my air conditioning apparatus shown, described and claimed in my Patent No. 2,009,817, issued July 30, 1935, for

Refrigerating and dispensing apparatus, and in other devices of the character of the latter example, quick and effective efrosting is highly desirable. This application is a continuation in part of the aforesaid patent.

In any such arrangement where air is circulated in a return bend through-a series of ex: pansion tube coils, partitions are utilized, and an object of this invention is to so construct such partitions that they may be provided. with heating means which may quickly raise the temperature of these partitions and thus cause the air to pass in contact with heating surfaces as it passes over the cooling elements which during this heating, are defrosted and preferably shut off from the refrigerant, that is, the'flowof refrigerant is discontinued during the defrosting intervals.

Further objects include the simple emcient construction of such heating and defrosting 3 means, providing for a cheap assembly of it with the cooling unit.

A more specific object is tois'o construct walls or partitions in a cooling unit that I may elec- 'trically heat the same for the purpose of de- 35. frosting.

Other objects and advantages will become more apparent in the following description which relates to the accompanying drawing in which:

Fig.1 is a sectional view illustrating a condensing or expansion type of refrigerating device through which air is passed by forced circulation.

Fig. 2 is a side elevation of-rny evaporator unit showing the partitions adapted. to be heated therein. I 45 Fig. 3 isa sectional line 3-3 of. Fig. 2.

In the drawing Fig. 1 shows a structure similar to that of Fig. 1 of my prior application'No. 731,657, above referred to and to which reference may be had for more detailed description 0! its operation.

For convenience we will here again briefly describe the construction shown as illustrative of any use or embodiment of the present invention.

I indicates a suitable casing having insulation plan of the same on the .thence to a storage tank unit is disconnected from t, surrounding a metallic chamber l0 enclosing theexpansion or cooling coils ii of a refrigerating unit. A suitable compressor and driving mechanism is indicated at l8 and driven by a motor designated 20. Fromthe coil Ii to the 5 compressor is a return passage or tube 22. From the compressor the liquid refrigerant passes through condenser coils indicated at 24 and from which it passes through a tube 21 to a suitable expansion valve 10 connected with the expansion and refrigerating coils l5.

The coils are divided by partitions 32 below which is an opening 33, air being impelled by a fan indicated at 40 of the Sirroco" type and Ill driven by a motor as shown at 42. The air passes upwardly from the fan through a passage 44 to the chamber (not shown) to be cooled, and thence returned to the casing I0, thus, the refrigerated air is circulated over any food or other 20 material to be refrigerated or cooled.

While in the operation of suclra system, I have, by the use of specially constructed expansion valves effected a high degree of control of the humidity as described in 'my copending applica- 25 tion, referred to, defrosting becomes necessary or at least desirable at intervals and it is essential and economical to effect quickly.

In the use of such cooling coils for various refrigerating systems it is well known that such requirements for defrosting afford a diillculty, in that the foods or other materials .being preserved, must during the defrosting period, be subjected to warm air over long periods, while the frost and ice accumulation on the coils slowly melts. Wherever possible, of course the refrigerator,

the preservation chamber, but frequently this is not possible and in most instances the entire apparatus must be the defrosting most emptied of its foods and other material for such defrosting.

By the present invention I am enabled however, to completely defrost and in fact effectively dry the refrigerating coils in a very few minutes. 4

My-preferred method is that illustrated in Figs. 2 and 3, in which I have shown the cooling unit as comprising the plurality of looped portions of the tube I, having parallel reaches ll connected by return bends 52. The parallel portions being provided with spaced fins or heat radiating members 5|, the parallel portions and radiating fins being housed in a suitable box like case I. I

Intheupper righthand corner ofthiscaseil indicated a fan housing represented by the broken lines 62 and line 63 indicates an outlet passage.

' The casing isshown as divided into three sections by the partitions l and I2, each of which stops short of reaching the full length of the casing to leave passages for air as indicated by the broken line, arrows i4 and 15. The air inlet opening 16 is indicated by the broken'line arrows at the lower left of the casing.

These partitions ill and I2 are preferably of a hollow nature within which is included heating elements. Any kind of heating element may be V used, as for example, the resistance unit in an '"electric iron, the element being supported by. a

sheet of mica or like material to which the element is attached, and then'after insulating the indicated at $2.

-Obviously 'in the normal cooling operation of the coils the heating elements are idle but when it is desired to defrost, the conditions of the merchandise to be refrigerated having beensuitably taken care of, as by shutting off circulation thereto or by removing,'if desired, current is then supplied to the heating elements 80 by closing suit able switches, one of which is indicated at 85. The fan is continued in operation and the heat of the surfaces of the partitions l0 and I2, coming in contact with the air passing along both sides of each partition and also in contact with the reaches 50 of the coils transfers the heat thus delivered to the surfaces of the coils and very rapidly effects melting and evaporation. The de frosting is thus accomplished in a few minutes time. The circuit through the heating elements is then opened and the refrigerating may be immediately resumed.

While. I have described'the heating means as electrical, obviously other heating media may be used where conveniently available. For example, hot water or steam may be circulated through a hollow partition or through tubes built into the partitions or wall surfaces.

Other modifications, such as the providing of heating elements in the-walls of the casing, for

process cooling unit, may be provided with electric or other heating units.

Having thus described my invention, I claim:

1. The combination with a cooling coil of a refrigerating apparatus, of a casing embracing portions of said coil and having wall members efiecting a circuitous passage therein, means for forcibly circulating air in said passage and means for heating a wall surface of the passage.

2. The combination with the expansion coil of a. refrigerating apparatus of a casing embracing a plurality of reaches of said coil, a partition dividing the casing for a portion of the'distance across one wall thereof to another, inlet and outi let air orifices, a fan for moving 'air through said passage, said partition having electric heating elements therein adapted to facilitate defrosting of the coil.

3. In a refrigerating system of the compression-expansion type, the combination with an evaporator having parallel reaches, of a supporting member for said reaches and forming a passageway for air to be circulated therethrou gh,

means connected to said reaches for causing heat and cold transmission thereto, a means for causing a circuitouspassage of air through said evaporator, and a means associated with said evaporator for heating said last mentioned means.

4. The combination with the expansion coil of a refrigerating apparatus, of a casing embracing a plurality of reaches of said coil and forming an air passageway, a means providing a circuitous air passageway, said means having electric heating elements therein adapted to defrost said reaches of said coil, and a fan for moving air through said passageway.

5. The combination with the expansion coil of a refrigerating apparatus, of a casing embracing a plurality of reaches of said "coil and'forming an air passageway, a means providing a circuitous air passageway, said means having electric heating elements therein adapted to defrost, means for the transfer of heat and cold to the reaches of said coil, and a fan for movingair through said passageway.

CLARENCE A. R ODMAN.

example, the vertical walls of the case 60 of the

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