US2370267A - Refrigerating apparatus - Google Patents

Description

R. H. STARR REFRIGERATING APPARATUS Filed June 6, 1941 o M ./J f. nl! f .@R ,m Y o Z N e E o .mY/...hmm I WM n 6. 0 A 2; M021/ Z 7 MW CSZW/ W/Y w 3 M All .m ons e w. \wm T u [i m J Feb. 27, 1945.

Patented Feb., 2?, i945 UNITED l STATES PATENT OFFICE 2 Claims.

This invention relates to refrigerators, storage compartments, coolers, and the like, which are supplied with a refrigerating medium expanded or circulated through a heat exchange unit contained therein.

It is well known that such units operate emciently when the exterior surfaces thereof are substantially free of ice accumulations, but due to operating conditions, moisture content of the stored commodities and admission of moistureladen air through door openings, the refrigerating surfaces of the units rapidly collect the moisture in the form of ice and they soon become so heavily coated that they cannot operate efficiently. It is then necessary to defrost the units by raising temperature of the refrigerating surfaces above the melting point of the ice. In large storage compartments containing perishable commodities, this is a most serious problem because the necessary rise in temperature results in injury of the commodities, particularly frozen products. As an alternate, the ice may be scraped from the coils, but due to their location and heavy loading of the compartments they are .practically inaccessible. Consequently, defrosting is delayed until such time that defrosting becomes imperative, with the result the refrigerating units are operated ineiiiciently.

It is, therefore, a principal o bject of the present invention to concentrate accumulation of the moisture at an accessible point and prevent ice formation on the heat exchange units which are depended upon in maintaining the desired refrig` erating temperatures.

It is also an object of the invention to provide a moisture accumulator adapted to be located directly in path of the moisture-laden air which enters the refrigerating compartment upon opening of the door thereof.

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

Fig. 1 is a perspective view of arefrigerator equipped in accordance with the present invention, parts of the walls being broken away to better illustrate the location of the refrigerating and moisture collecting units.

Fig. 2 is a longitudinal section through the refrigerator.

Fig. 3 is a diagrammatic perspective view of the moisture collecting and refrigerating units, the condensing unit associated therewith, and the Application June 6, 1941, Serial No. 396,841

valves controlling relative temperatures of the respective refrigerating and moisture collecting units.

Referring more in detail to the drawing:

5 l designates a refrigerator such as used in storing perishable commodities and includes insulated side walls 2 3, front and rear walls 4-5, a floor 6, and top 'I forming an enclosed storage compartment 8 to which access is had through a lo door opening 9 that is provided in the front Wall 4, the opening being closed by a door l0.

The refrigerating compartment is provided with a primary heat exchange or refrigerating unit II, supplied with a refrigerating medium l5 from a condensing unit I2. The unit I2 is shown as including the usual compressor I3 having connection with the heat exchange unit II through a suction line I4, a condenser I5 connected with the discharge of the compressor, and a receiver I6 having connection with the condenser I5, and

with the unit II, by a high pressure line Il.

The refrigerating medium is delivered to the heat exchange unit' II under control of a thermostatic expansion valve I 8, as in conventional practice, and the suction line I4 'is provided with a constant pressure valve I 9 to cooperate with the expansion valve in maintaining a substantially constant pressure in the heat exchange unit, the valves being selectively controlled to carry a pressure necessary in maintaining a predetermined temperature of the refrigerating surfaces 20 of the heat exchange unit.

In the illustrated instance the heat exchange unit II is shown as mounted adjacent the rear wall 5 and remote from the door I0.

In storage refrigerators of the type illustrated, the commodities are closely packed so as to reduce the air space within the refrigerating compartment. Upon opening of the door, to gain access to the compartment, warm air enters the top of the door opening to replace the heavier cold air passing through the lower portion of the door opening. The warm air, upon contacting the refrigerating surfaces of the heat exchange, or reture content which condenses on the refrigerated surfaces and freezes to form an ice coating thereover. This coating rapidly builds up in thickness and is aggravated in accordance with the frequency that the door is opened. Consequently, the heat exchange unit ybecomes so heavily coated with ice that it is diiilcult to maintain the desired temperature in the refrigerating compartment. It then becomes necessary to remove the thermostatic expansion and constant pressure ice therefrom. As above pointed out, removal of frigerating, unit II, immediately loses its moisthe ice is diillcult and is likely to result in spoilage of the stored commodities.

It is well known that escaping tendency of water vapor from the ice collected upon the heat exchange unit is greater the higher the temperature of the ice. Hence water vapor from ice on a warmer heat exchange surface has a greater escaping tendency than on`a colder heat exchange surface.

In carrying out the present invention, I utilize this principle in effecting transfer of ice formation from a warmer to a colder heat exchange surface, as now to be described, the surfaces Iof the heat exchange unit I being the warmer surface. In supplying the colder surface, the compartment is provided with a secondary or smaller heat exchange unit 2| which is located at an accessible point within the storage compartment and preferably in the direct path of the warm air which is admitted to the compartment upon opening of the door l0. The secondary unit 2l is, therefore, located in close relation with the ceiling of the compartment and over the door opening 9, as shown in Figs. 1 and 2. A

In order to control formation of ice thereon. the secondary unit is preferably located so that only the readily accessible lower surface 22 thereof is subject to accumulation of the moisture in the form `of ice which is adapted to be removed readily therefrom by a suitable scraper manipulated through the door opening and without removal or interference with the stored commodities.

The secondary unit is maintained at a lower temperature than the main or primary refrigerating unit throughrefrigerating medium supplied by a pipe 23 having connection with the high -pressureline l1 and in which is interposed a thermostatic expansion valve 24. The discharge side of the secondary unit is connected by a similar pipe 25 With the suction line Il and interposed therein is a constant pressure valve 26, the valves 24 and 26 being set to maintain a lower temperature in the heat exchange unit 2| than in the unit Il. For example, the valves I8` and I9 may be set to maintain a temperature of 1 F. of the primary unit and the valves 24 and 26 set to maintain a temperature of 11 F. for the ice collecting surface 22 of the secondary unit 2|. With this arrangement, the surfaces .20 of the primary refrigerating unit being of higher temperature than the ice accumulating surface 22 of the secondary unit 2|, the water vapor from the ice or frost tending to collect on the primary is transferred to the secondary unit. Consequently the secondary unit collects the moisture which would normally accumulate upon the surfaces of the primary refrigerating unit and the main refrigerating unit is kept at high operating efficiency. When the frost or ice accumulates upon the collecting surface 22, it is a simple matter to effect removal thereof since it is readily accessible through the door opening without disturbing the stored com- Imodities.

Attention is also directed to the fact that when the door is opened and Warm air enters through the top of the opening, it passes directly over the chilled surface ofthe secondary unit to effect dehydration and deposit of the moisture on the surface 22 thereof before the air passes into contact with the main unit.

From the foregoing it is obvious that I have provided a simple and inexpensive means for preventing accumulation of ice upon a main refrigerating unit of a storage compartment or the like and I have provided for concentration of the moisture in the form of ice at a point which is readily accessible.

What I claim and desire to secure by Letters Patent is:

1. In a refrigerator having a storage compartment and a door admitting access to said storage compartment, a pair of cooling units having surfaces exposed to air in the compartment, one of said units being located in said compartment within ready access through the door opening without removal of contents from the storage compartment, and means for supplying a refrigerating medium to said units under such conditions as to maintain the unit that is located within said ready access through the door opening at a lower temperature below freezing than the other unit, said cooler unit having a substantially flat surface area of such size that when free of frost and moisture it will effect condensation and freezing thereon of the moisture contained within the air inside said storage com partment substantially without such condensa-v tion and freezing of the moisture occurring upon the warmer unit.

2. In a refrigerator having a storage compartment, a pair of cooling units, one having heat exchange surfaces of different area than the heat exchange surfaces of the other unit, said units' being exposed to the air in the storage compartment, the unit of lesser heat exchange area being located in said compartment for ready access thereto without removal of contents from the storage compartment, and means for supplying a refrigerating medium to said units under such conditions as to maintain the unit having the smaller heat exchange area and that is located within said ready access at a lower temperature below freezing than the other unit, said cooler unit having a substantially fiat surface area of such size that when free of frost or moisture it will effect condensation and freezing thereon of moisture contained within the air inside said Y storage compartment substantially without such condensation and freezing of the moisture occurring upon the warmer unit.

RAYMOND H. STARR.

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