US2707871A - Refrigeration apparatus - Google Patents

Description

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Mag,t l0, 1955 w. G. MocEY 2,707,871

REFRIGERATION APPARATUS Filed Oct. 31, 1952 United States Patent 2,7ii'7,8 71 Patented May 130, 1955 ice REFRIGERATION APPARATUS Walter G. Mocey, Philadelphia, Pa., assignor to Philco Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application October 31, 1952, Serial No. 317,984

2 Claims. (Cl. 62-99) This invention relates to refrigeration apparatus of the kind having a storage compartment cooled by a vertically disposed plate type evaporator, and the invention has as its primary object the prevention of moisture accumulation upon certain portions of the wall structure which defines the compartment.

It is now recognized that a desirable way of constructing a refrigerator comprises dividing the space defined by the inner liner of the cabinet into upper and lower compartments by means of a generally horizontal partition which serves as the bottom of the upper compartment and the top of the lower compartment, and isolates the two compartments in such manner as to prevent contact of air within one compartment (usually the lower) with the low temperature evaporator which cools the upper compartment. ln order to refrigerate the lower compartment it is known to provide a vertically extending plate-like evaporator disposed in closely spaced adjacency with respect to a rear wall of that compartment. One such refrigerator is disclosed and claimed in the copending application of Malcolm G. Shoemaker, bearing Serial No. 296,995, filed July 3, 1952, and assigned to the assignee of the present invention.

While constructions of this general character are well known and are advantageous, they have been found in practice to be subject to a disadvantage in that moisture tends to condense and accumulate upon portions of the top wall of the lower compartment. This condensation is generally localized, being limited to the rear portions of the top wall, that is, portions which overlie or are closely adjacent to the upper part of the plate-like evaporator aforesaid. The reason for this accumulation will be understood when it is recognized that in a compartment refrigerated by such a vertically extending evaporator these surface portions tend to be maintained at a temperature somewhat lower than the temperature of other surfaces disposed within the compartment and, also, there is relatively little circulation of air in this region.

Respecting the relative lack of circulation in this area, it is to be understood that a compartment of this type is cooled by a convectional, circulatory flow of air which takes place downwardly past the low temperature forward surface of the evaporator and upwardly through opposed zones of the compartment spaced from the evaporator. There is a tendency for the warmer, upwardly moving air to return to the cooled plate by curving downwardly in a streamline path such that the rear portion of the underside of the partition is not swept with warm air.

To overcome this difliculty, and to achieve the general objective indicated above, the invention contemplates provision within the compartment of an air defiector or baffle which is spaced somewhat from the top wall of the compartment, preferably underlies the region of condensation only, and has its rear edge so disposed, as respects the upper edge of the plate-like evaporator, as to cause said baffle to define-in cooperation with the top wall of the compartment-a passage through which a portion of the circulating air moving backwardly toward the evaporator flows across the stated region of the top wall and downwardly behind the evaporator. It is of importance that the baffle not be refrigerated, and that it be maintained out of conductive association with the evaporator.

While the primary flow of air in such a refrigerator is downwardly across the front surface of the evaporator, there is also a tendency for air, as it is cooled, to be drawn downwardly through the space between said evaporator and the adjacent portions of the rear wall of the compartment. A baffle constructed and arranged in the manner aforesaid utilizes the mentioned tendency and draws air across the rear portions of the top wall, thereby preventing condensation of moisture upon such portions.

The manner in which the foregoing and other objectives of my invention may best be achieved, will be more clearly understood from a consideration of the following detailed description, considered in conjunction with the accompanying drawing, in which:

Figure l is a fragmentary, side sectional view illustrating a two-compartment refrigerator embodying apparatus in accordance with the invention; and

Figure 2 is a perspective illustration of the upper, forward portion of the refrigerator.

Now making more detailed reference to the drawing, it will be seen that the invention is therein illustrated as embodied in a household or domestic refrigerator comprising an outer shell 10 and an inner shell or liner member 11 spaced and insulated from the outer shell 10 by any suitable insulation shown at 12. A pair of doors seat against the forward face of the cabinet, seating the same and providing access thereto. lt will be understood that the refrigerator also includes circulating means for example, a compressor-condenser unit of any desired type, but illustration of this portion of the apparatus is not necessary herein since the present invention is not concerned therewith.

As indicated above, and as clearly appears in the drawing, the refrigerator is of the type in which the space within the inner liner 11 is sub-divided into an upper relatively low temperature freezing compartment which, in the embodiment shown, is defined by an evaporator 13, and a lower main food storage compartment 14, division being effected by means of an insulated partition designated by the reference character 15. The partition spans the width and depth of the space defined by the inner liner 1i and is so constructed, and disposed within the cabinet, as thermally to isolate the two compartments, preventing contact of the air within the main lower compartment with the low temperature evaporator 13.

In order to refrigerate the lower compartment it is provided with a plate type evaporator 16 which extends vertically within said lower compartment, being spaced somewhat from the rear wall of the latter. Since thermosyphonic movement of air is relied upon to refrigerate the compartment 14, and since the quantity of air which can move, convectionally, downwardly through the restricted space behind the evaporator is insuflicient to provide adequate refrigeration within the compartment, the evaporator must be of such a character as to cause its front surface to be maintained at a relatively low temperature in order that substantial circulation across said front surface will occur. To this end, evaporator 16 comprises a metal plate of high thermal conductivity having bonded to its rear surface suitable refrigerant tubing 17 which latter, together with upper evaporator 13, is connected in refrigerant flow relationship with the condensing unit (not shown). The normal circulatory flow of air which cools the compartment 14 is clearly shown by solid-line arrows applied to Figure 1.

In particular accordance with the present invention, an

air deflector, or baflle structure 1S is provided within the compartment M, this structure comprising a relatively thin metallic sheet 19 spaced beneath the rear part of the top wall of the compartment, that is, so located as to underlie the aforesaid zone of condensation. The sheet 19 spans the width of the cabinet and is carried by the side walls of the compartment in any convenient manner, as through the agency of track-like supports shown at 20. in order to space the forward edge of the sheet i9 somewhat below the top of the cornpartment, and to improve the appearance of the baille structure, the sheet carries at its forward edge an upwardly turned ange portion 21 which is provided with a plurality of air inow apertures shown at 22. The bathe preferably has slight downward inclination toward the rear of the compartment, and its back edge 23 lies closely adjacent to the upper edge of the plate-like evaporator lo. inclination of the battle serves a dual purpose, decreasing the frictional resistance presented to the air flowing through the passage above the baille and delivering to the face of the evaporator 16 any drops of moisture which may, under unusual circumstances, collect upon the upper surface of the bafiie, Moisture thus passed to the surface of evaporator lo is delivered to any suitable drain, as for example the drain structure indicated at 24 in Figure l.

lt is to be noted that the baffle does not extend for wardly within the cabinet beyond a distance just sufcient to underlie the area of condensation. This factor is of importance, since extension of the baffle to the front of the compartment 14 would result in an undue increase in the resistance to air flow through the space above the baffle, and consequent reduction in the effectiveness of the structure. Further, air circulating within the refrigerator follows a path of streamline contour, and in order that a suicient quantity of the circulating air may be delivered to the space above the baffle, in the manner indicated by broken-line arrows applied to Figure l, its forward or inlet edge is preferably disposed rearwardly of the midpoint of the depth of the cabinet. A baille of this kind has been found completely to eliminate the aforesaid condensation difficulty, and to have a noticeable effect in maintaining desired temperatures throughout the compartment i4. In this latter connection the baille tends to reduce the thermal gradient throughout the height of the compartment.

Considering the operation of apparatus constructed in accordance with my invention in somewhat greater detail, it will be seen that there are two operational advantages which, together, result in virtually complete elimination of condensation.

Firstly, the bathe provides positive circulation of air across the critical surface arcas of the partition l5, thereby insuring a supply of relatively dry air. There is a change in density, due to heat transfer to the evaporator i6, of air confined between the rear surface of the evaporator and the back wall of the compartment. in changing density the air moves to a lower level, thereby creating a reduced pressure area in the region of the top of the evaporator, and as will now be understood this pressure reduction is utilized to create the aforesaid positive circulation. Secondly, the baffle structure 18 is instrumental in raising the temperature in the region concerned above the dew point temperature of the moisture-laden air within the refrigerator, The air passing above the baille is ot course at a more elevated temperature than air in contact with the evaporator, or present in the lower part of the refrigerator, and it is also to be borne in mind that the relatively low thermal mass of the unrefrigerated baffle causes the baille itself to warm rapidly, under the influence of the circulatory flow of air which it induces. This warming of the baffle further assists in maintaining the temperature, in the region above Cil the baiile, at a value in excess of the dew point. lf refrigerant were to be circulated in heat exchange relation with the bathe structure, it will be evident that reduction in the temperature above the bafe would occur, and condensation would result. The term bale, as used in the appended claims, should be understood with this in mind.

ln summary, and as will now be well understood, there is provided, by this invention, refrigeration apparatus of the plate-cooled type having in novel combination therewith bafe structure so constructed and arranged as to result in virtually complete elimination of a condensation problem formerly encountered in refrigerators of this kind. lt is to be noted that the construction, disposition, and the extent of the baflle structure all contribute to achievement of this result.

l claim:

l. in refrigeration apparatus, a storage compartment including top, bottom and side walls, a plate type evaporator having cooling means bonded thereto, said evaporator extending generally vertically within the compartment in closely spaced adjaeency to one of the side Walls thereof, the front surface of said evaporator being maintained at a relatively low temperature during normal operation of the apparatus whereby the compartment is cooled primarily by a convectional current of air circulating downwardly past the front surface of said evaporator and upwardly through an opposed region of the compartment spaced from said evaporator, there further being a tendency for air to flow downwardly through the space between said evaporator and the adjacent wall of the compartment, and means for utilizing the last- Mentioned ow of air to prevent condensation of moisture upon the top wall of the compartment in a restricted region extending somewhat forwardly from the plane of said evaporator, said means comprising an air deiiecting baffle spaced from said top wall and underlying the said region only, the rear edge of said baffle being so disposed, as respects the upper edge of said evaporator, as to cause said baille to detine, in cooperation with the top wall of the compartment, a passage through which a portion of the circulating air ows across the stated region of said top wall and downwardly behind said evaporator.

2. In refrigeration apparatus, a storage compartment including top, bottom, side and rear walls, cooling means within the compartment comprising a plate-like member of high heat conductivity extending generally vertically within the compartment in spaced adjacency to the rear wall thereof and having an upper edge close- ]y underlying said top wail, said plate-like member having in high heat exchange relation therewith a refrigerant flow passage to maintain said member at a relativeiy low temperature, the construction and arrangement being such that during normal operation of the apparatus the compartment is cooled primarly by a convectional circulatory liow of air downwardly past the front surface of said member and upwardly through a portion of the compartment spaced from said member, and means for promoting iiow of air across a restricted region of the rear part of said top wall generally overlying said membcr, said means comprising an air deector spaced from said top wall and extending beneath the said region, said deiector having a rear edge portion disposed in closely spaced adjaceney with respect to the upper edge of said member.

References Cited in the tile of this patent UNITED STATES PATENTS 2,085,346 Vretman June 29, 1937 2,298,896 Meyer Oct. 13, 1942 2,501,540 Ryan Mar. 2l, 1950

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