US3648482A - Method and apparatus for producing refrigerating constructions - Google Patents

Abstract

A refrigerated enclosure including driven airstreams circulating across an access opening to the enclosure. Passages for carrying the streams are located in the top, back and bottom walls of the enclosure. The passages are formed by solidifying foam around pattern members with metal foil being located on the interior surfaces of the passages.

Description

States Paten Beckwith ct ail.

[ 51 Mar. M, 11972 [54] METHOD AND APPARATUS FUR PRODUCING REFRIGERATING (IONSTRUCTIONS [72] lnventors: Sterling Beckwith, Menlo Park, Calif.;

Robert E. Vogel, Deerfield, lll.

[73] Assignee: Kysor llndustrial Corporation, Cadillac,

Mich.

[22] Filed: Sept. 5, 1969 [2]] Appl. No.: 870,713

Related US. Application Data [62] Division of Ser. No. 623,685, Mar. 16, 1967.

[52] US. Cl ..62/256, 62/426, 62/272,

62/419 [51] Int. Cl. ..A47ii 3/04 [58] Field otSearch ..62/255, 256,426, 272,419

MacMaster ..62/256 Primary Examiner-William J. Wye Attorney-McDougall, Hersh & Scott [57] ABSTRACT A refrigerated enclosure including driven airstreams circulating across an access opening to the enclosure. Passages for carrying the streams are located in the top, back and bottom walls of the enclosure. The passages are formed by solidifying foam around pattern members with metal foil being located on the interior surfaces of the passages.

15 Claims, 15 Drawing Figures Sheets-Sheet l INVENTORS 5 M 6. 5E mw Pafemed March 14, 1972 3,648,482

4 Sheets-Sheet i:

INVENTORS Sierlz'lgg Beckwzih Patented March 14, 1972 3,648,482

4 Sheets-Sheet L INVENTORS Sibrlirz Beckwz' 2 1 METHOD AND APPARATUS FOR PRODUCING REFRIGERATING CONSTRUCTIUNS This is a division of my copending application Ser. No. 623,685, filed March 16, 1967, and entitled Method and Apparatus for Producing Refrigerating Construction.

This invention relates to improved methods and means for building equipment utilizing refrigerating means. The invention is particularly concerned with refrigerated constructions which utilized moving streams of air employed for purposes of creating refrigerated conditions in areas of the construction located within or adjacent to the paths of the air streams.

In describing the instant invention, reference will be made to certain refrigerated cabinet constructions. In such constructions, air curtains are moved across an access opening for the cabinets and the character of the curtains is important with regard to efficient operation of the construction.

In Hagen et al. U.S. Pat. No. 3,134,243 and in Simons U.S. Pat. No. 2,862,369, there are described refrigerated display cabinets which are provided with access openings exposed to the atmosphere while still being capable of maintaining the contents in a refrigerated state. Loss of refrigeration from the enclosed space through the access opening is reduced in a highly effective manner in these constructions by the use of a gaseous, preferably air, curtain which is continuously advanced across the open side from one edge of the opening to the opposite edge.

The air curtain in these constructions is adapted to be formed of adjacent panels of air, with the innermost panel comprising a refrigerated cold air panel, and with one or more outer panels having temperatures approaching the ambient temperature. It has been found that it is desirable to recirculate the inner cold air panel and to provide means for circulating the adjacent guard panels, to conserve the refrigeration and to maintain the enclosed space in a satisfactory refrigerated state.

Copending application Ser. No. 613,802, entitled System for Defrosting of Refrigerating Constructions describes a refrigerated cabinet construction which includes horizontally disposed passages in top and bottom walls and vertically disposed passages in a back wall. The vertically disposed passages are situated in side-by-side relationship with the two innermost passages extending to pairs of horizontal passages in the top and bottom walls. These horizontal passages fan out from their juncture with the vertical passages to provide wide outer ends which are substantially coextensive with the cabinet opening. Outer vertical passages communicate with similar upper and lower pairs of horizontal passages. Dimensional control of the respective passages is maintained to provide for ideal air flow.

The instant invention is directed to improved techniques for the production of cabinets of the type described in the afore mentioned application. This invention is also directed to novel refrigerating coil constructions which operate in an extremely efficient manner when associated with cabinets produced in accordance with this invention.

It is, therefore, the object of the instant invention to provide improved techniques for the production of refrigerated cabinets and for the production of refrigerating coils to be used in conjunction with such cabinets.

Other objects and advantages of the invention will appear hereinafter, and for purposes of illustration, but not of limitation, specific embodiments of the invention are shown in the accompanying drawings in which:

FIG. 1 is a vertical, sectional view of a cabinet construction produced in accordance with the techniques ofthis invention;

FIG. 2 is a horizontal sectional view illustrating refrigerator coil compartments in the construction;

FIG. 3 is a detail view illustrating the refrigerator coil construction;

FIG. 4 is an enlarged end view of one form of coil construction;

FIG. 5 is an enlarged cross-sectional view of a modified form of coil construction;

FIG. 6 is a side elevation of the modified form shown in FIG.

FIG. 7 is a detail view illustrating the side of the coil construction shown in FIG. 5;

FIG. 6 is a cross-sectional view of ployed in the formation of air refrigerated construction;

FIG. 9 is a perspective view illustrating the core parts employed in the assembly shown in FIG. 8;

FIGS. 10 and 11 illustrate additional core parts used for forming other portions of the cabinet; and,

FIGS. 12 through 15 illustrate pattern constructions employed in the manufacture of the passages utilized in the cabinet construction.

As noted, the instant invention will be described with reference to constructions which employ air curtains moving in side-by-side relationship across an access opening of the refrigerated cabinet construction. Such air curtains are commonly employed for the purpose of forming barriers to prevent or minimize heat transfer.

The invention will be specifically described with respect to refrigerated enclosures of the type defining an access opening in one wall whereby communication with the space within the enclosure can be accomplished. The enclosures or cabinets of this invention are provided with a plurality of nozzles arranged in side-by-side relationship across one edge of an access opening and corresponding inlets are located across the opposite edge of the access opening. The inner nozzles and inlets are provided for the passage of a refrigerated stream across the access opening while the adjacent outer nozzles and inlets circulate progressively warmer air panels. The inner refrigerated stream is circulated through a passage having refrigeration coils located therein and one or more of the outer adjacent streams may also be refrigerated.

FIG. ll illustrates a refrigerated calbinet design of the type described in the aforementioned application. The construction comprises a refrigerated cabinet 10 which includes a top wall 12, a bottom wall 14, a back wall 16 and a front wall 18. The front wall 18 defines an opening 20 which provides access to the interior 22 of the refrigerated cabinet. An inner wall 24 defines the extent of the refrigerated space.

The cabinet comprises outlet nozzles 26 and 28 and inlets 30 and 32. Accordingly, the construction is adapted to provide for the movement of panels of air 34 and 36 across the access opening 20.

The inner, refrigerated panel of air 36 is delivered to the nozzle 28 through a pair of passages, one of which comprises passage 40. As set forth in the aforementioned case, a second passage is located at the side of the passage 40 with the front ends of the passages being substantially coextensive with the outlet 28. These side-by-side passages communicate with rectangular, vertically disposed passages 42 and 44 extending upwardly along the back of the construction (see FIG. 2). Substantially horizontal continuations are provided at the lower ends of the passages 42 and 4-4. The refrigerated air panel moving across the access opening enters the inlet 32 for entry into these passages, one of which is shown as passage 46.

A similar arrangement is provided for the guard panel issuing from the nozzle 26 and entering the inlet 30. Substantially horizontal passages collect the incoming air, These passages communicate with vertical passages 48 and 50, and these passages in turn communicate with upper horizontal passages. FIG. 2 illustrates the location of the vertical passages while FIG. ll shows lower passage 52 and upper passage 54, each communicating with vertical passage 50.

As best shown in FIG. 1, a third duct 56 is located at the top of the cabinet. A circulating fan 58 draws air into this duct for passage out through nozzle 60. With this arrangement, a stream of ambient air is forced downwardly adjacent the guard panel of air issuing from the nozzle 26.. This additional panel of air tends to reduce turbulance as the air panels move across the access opening of the cabinet. Specifically, the additional panel will tend to prevent spilling of any air from the guard panel beyond the inlet 30. This, of course, serves to avoid any spilling of air from the refrigerated panel. The additional panel of ambient air is directed whereby the air in the panel will spill outside the cabinet.

a molding assembly empassages for use in building the Refrigerating coils 62 can be located within the lower substantially horizontal passages 46 and 64. Circulating fans 66 are located within the vertical passages. Access to the fans for maintenance purposes is simplified by providing removable plates 68 for access to the fans from the interior of the cabinet.

As noted in the aforementioned case, defrosting can be accomplished through the use of a door 70 located at the top of each of the passages 42 and 44. When pivoted to the position shown in FIG. 1, the respective passages 42 and 44 communicate with the outside atmosphere through outlet conduits 72. During defrosting, ambient air is drawn into the inlet 30 and is circulated through the outer passages. The air then passes out of the nozzle 26 and then into the inlet 32 where it contacts coils 62. The air then passes up through the passages 42 and 44 and into the atmosphere through the outlet conduits 72.

In forming the cabinet, light insulation material such as Styrofoam can readily be utilized. Such material, however, tends to heat up slowly and any frost collecting on the surfaces will, therefore, be more difficult to remove. Accordingly, the instant invention contemplates the provision of thin sheets of material which will conduct heat at a high rate. The ambient air will, therefore, remove frost from such surfaces in a more efficient manner. Sheets of aluminum foil serving as linings for the passage walls are suitably employed for this purpose.

The construction of the substantially horizontal passages is similar in many respects. Referring to the bottom of the cabinet, it will be noted that the passages 52 are located at a lower lever than the passages 46 and 64. All of these passages are tapered whereby a relatively long, narrow mouth portion is presented to the inlets 30 and 32. The taper is such that relatively short but wide openings are provided at the opposite ends of the passages for communication with the vertically disposed passages. As shown in FIG. 2, the lower passages taper toward the exterior pair of vertical passages 48 and 50 while upper passages 46 and 64 communicate with vertical passages 42 and 44. It will be noted that in the design illustrated, the refrigerated streams are maintained away from the exterior walls to provide minimum cold loss.

In the case of the passages 46 and 64, a relatively large interior cross section is desirable. This permits location of suitable refrigerating coils within these passages. The preferred design for such coils will be referred to hereinafter.

The upper horizontal passages are designed along the same lines as the lower horizontal passages. As noted in the aforementioned case, however, specific dimensional limitations are applied in the formation of these upper passages. Thus, a specific taper is provided in each upper passage from the outlet nozzles to the point of communication with the vertical passages. Specifically, in horizontal section, the air stream moves from a small dimension to a large dimension, while in vertical section, the opposite is true. By properly controlling the taper, the upper passages can be designed whereby the cross-sectional area at any given point in the passages will be substantially the same as the area at any other point. For example, the passages 42 and 44 may have dimensions 4 inches by 9 inches for a cross-sectional area of 36 inches. The entry end of the passage 40 will have this same dimension; however, the four inch dimension will taper downwardly to a I% inch dimension at the outlet end of the passage 40. The nine inch dimension on the other hand will increase to 24 inches adjacent the outlet nozzle whereby a cross-sectional area of 36 inches is maintained.

By controlling the cross-sectional area within the passages, a minimum amount of disturbance of the air streams will be realized. There will be no significant disruption as might occur where different cross-sectional areas would cause change in air pressure and change in speeds.

FIGS. 2 through 7 illustrate in detail a preferred form of refrigerator coils 62. It will be noted that the coil construction includes an upper manifold 80 and a lower manifold 82. Refrigerating liquid is adapted to be circulated through these manifolds and to the coil elements connected to the manifolds. The coil elements include an upper tubular portion 84 which extends rearwardly from the upper manifold to loop 86. An intermediate portion 88 extends between this loop and a second loop 90. Lower portion 92 extends to a connecting tubular portion 94.

The connecting portion 94 extends to a second upper tubular portion 96 which in turn extends to loop 98 intermediate portion 100, loop 102 and a second lower portion 104. This second lower portion extends to lower manifold 82.

FIG. 3 illustrates two adjacent coil arrangements in a flattened position. It will be apparent that when these two portions are bent to form a loop in connecting tubular portion 94, they will be situated in side-by-side relationship.

A plurality of plates 106 are welded to the respective coil assemblies to provide sandwich-like assemblies. In a modified form of the invention, a plurality of openings 108 may be formed in the sides of the plates 106. The jagged edges surrounding these openings act as frost collectors. It has been found that the frost can be more rapidly removed when it is collected in this manner. It will be noted when considering FIG. 5 that adjacent openings are pierced in opposite directions whereby maximum exposure of the jagged edges can be achieved.

As previously noted, the passages 46 and 64 which hold the coils are tapered whereby the front openings of the passages will be substantially coextensive with the lengthwise dimension of the inlet 32. The opening defined at the rear of the passages 46 and 64 is, on the other hand, of the same dimensions asthe vertical passages 42 and 44. Accordingly, a taper must be provided in the coil configurations. It will be apparent that the coil design illustrated is ideally suited for providing such a taper. The adjacent coil lengths can be bent into shape whereby a fanlike arrangement is achieved. It has also been found that the refrigerating efficiency of the coil design illustrated is extremely satisfactory.

FIG. 8 illustrates a mold construction 110 adapted to be used during formation of a cabinet characterized by the features of this invention. The mold is designed whereby a plurality of core elements can be set up in the mold, the core elements corresponding to the positions of the passages to be provided in the cabinet construction. A material such as Styrofoam" can then be introduced into the mold whereby all of the walls can be formed of insulating material. This arrangement provides a highly efficient means for forming the cabinet in that the major volume of the cabinet will be an essentially integral unit. Furthermore, an extremely light weight construction is realized in an arrangement of this type.

The mold construction consists of an exterior wall 112 and an interior wall 114. These walls rest on base elements 116 and 118.

A first metal liner 120 is located over the interior surfaces of the outer wall 112. This metal liner will form the outer surface of the completed cabinet. A second liner 122 is positioned over the inner wall 114, and this liner will form the interior surface of the cabinet.

A U-shaped structural member 124 is located in overlying relationship with respect to the inner liner 122. As more clearly set forth in the aforementioned application, this structural member may comprise a channel-shaped member, and one such member is located at each end of the cabinet. In some instances, one or more intermediate structural members can also be employed depending upon the length of the cabinet.

Supporting legs 126 are connected to the bottom arm of the U-shaped structural member. It will be apparent when considering FIG. 8 that the mold is arranged with the cabinet disposed in a face-down position.

FIGS. 9 through 11 illustrate core members which are situated within the mold whereby passages will be formed when foam is introduced into the mold. The core member 128 is provided for forming a vertical passage in the cabinet. Where a cabinet of the type shown in FIG. 2 is being produced, core 7 members 128 are used for forming the outer passages 48 and 50. These core members will be situated at the front and back of the mold 1 10.

Two intermediate core members 130 are provided for forming the vertical passages 42 and 44. Horizontal core members 132 and 134 are associated with the core member 130 for purposes of forming the horizontal passages. The core member 134 is of substantial thickness since the passage formed with this core member will retain the refrigerator coils. Passage 46 is formed with the core member 134 while a mirror image of this core member will form the passage 64. The core member 128 is associated with core members 136 and 138 in the mold. These core members form the uppermost and lowermost passages in the completed cabinet.

The core members preferably assume the configurations illustrated in FIGS. 12 through 15. Core members 128 are formed of complementary sections 140 and 142. With a core design of this type, the core sections can be removed after completion of a foaming operation without disturbing the integrally formed structure.

It will be noted that the top surface 144 of the core members 128 is positioned adjacent the liner 120. After foaming, an appropriate opening can be made in the liner at which time, the sections 142 of the core can be pulled outwardly. The section 140 can then be removed whereby a free passage will be provided. It will be noted that all of the core members are preferably wrapped in a highly conductive material, such as aluminum foil, before insertion in the mold. This material serves as an ideal separating material permitting foaming in place and subsequent removal of the cores. Furthermore, when the core members are removed, this foil will remain in place so that the formed passages will have a conductive liner. As noted in the aforementioned application, this greatly improves the efficiency of the defrosting operation.

A similar core construction is provided for each of the vertical cores 128 and 130. The cores utilized for forming the horizontal passages are also formed of multiple sections so that the cores can be removed without disturbing the integral structure of the cabinet.

FIG. 13 illustrates a core assembly making up core 136. The assembly comprises four pieces numbered 146 through 152. The core section 150 is of substantially uniform thickness and this piece can be pulled forwardly for removal from between the pieces 148 and 152. It will be noted that the leading end of the core will rest on top of the base 118 during forming. This end can, therefore, be exposed when the mold is lifted off the base, and this provides easy access to the core section 150.

Once the section 150 is removed, there will be sufficient space permitting removal of the sections 152, 148 and 146, in that order.

The core 132 is made up ofsections 154, 156, 158 and 160. The section 154 is of substantially uniform thickness whereby it can be removed after forming to thereby provide sufficient space for removal of the other sections.

A substantially similar arrangement prevails with respect to the core 138 shown in FIG. 15. This core includes three sections numbered 162, 164 and 166. The section 162 can be pulled outwardly from beneath the other two core sections to permit complete removal of the core sections.

It will be noted that the use of sections of the type described for forming the cores 132, 136 and 138 is extremely important. In each instance, these cores have tapers which would make it impossible to remove them if they were formed in single pieces. Accordingly, at least one of the core sections of each core must be of substantially uniform thickness or must have a reverse taper whereby this section can be removed. As soon as one section is removed, space is provided whereby the other sections can be removed. Accordingly, the concept of providing one core section which is to be the first section removed is critical to the provision of an integrally formed cabinet structure having the desired passages.

In the case of the vertical passages and in the case of the core 134, the dimensions are such that removal of a one-piece core is possible. The cores are, however, preferably formed in sections since it has been found that the cores can be removed more easily with such an arrangement. The foil covers for all of the cores will remain in place, particularly since there is some degree of adherence to the plastic which is formed adjacent the foil surfaces.

The mold arrangement shown in FIG. 8 is particularly desirable since the structures within the mold can be readily located in position. Thus, the wall 114 provides a support for the inner liner 122, and this assembly in turn provides support for the structural members 124. The cores 132 through 138 can stand in place on the base elements 116 and 118 with the cores 128 being in turn supported on the upstanding cores. The outer wall 1 12 is located around this entire assembly.

In order to facilitate proper positioning, it is contemplated that pins could be formed in the various core elements. FIG. 9 illustrates pins 170 which are adapted to fit into openings 172 defined by the core 130. Similar pins 176 are associated with the leading edge of the core 132 for interfitting with the base element 118. Obviously, such pins can be provided at various locations on the core elements, and these will not in any way interfere with the operations described.

Where portions of the core structure, for example the end 144 of the core 128, are exposed, insulating material can be used to fill in the gap in the refrigerator wall. It will be noted with respect to the core that the passages 42 and 44 formed by this core extend to the door 70.

It will be understood that various changes and modifications may be made in the above described construction which provide the characteristics of this invention without departing from the spirit thereof particularly as defined in the following claims.

That which is claimed is:

1. In a construction comprising a refrigerated enclosure defining an open side for access to the interior of the construction, at least two air inlet means and corresponding outlet nozzles extending in side-by-side relationship across opposite edges of said open side, passages communicating the respective nozzles and inlets, circulating means operating to drive separate air streams through said passages and across said access opening, and refrigerating means located for refrigerating at least the innermost stream crossing said access opening, the improvement wherein said passage means includes a lower set of substantially horizontally disposed conduits for receiving air from said inlet means, substantially vertically disposed conduits communicating with said horizontally disposed sections, and an upper set of substantially horizontally disposed conduits for passing air from the vertical sections to said nozzles, at least said upper conduits having a tapered shape with one end adjacent said nozzles defining a relatively long and narrow mouth substantially coextensive with said nozzles, and with the other end adjacent said vertically disposed sections defining a relatively short and wide mouth for connection with said vertical sections.

2. A construction in accordance with claim 1 wherein said vertical conduits include at least two interior conduits disposed in side-by-side relationship, and at least two exterior conduits on opposite sides of said interior conduits, and wherein said horizontally disposed sections comprise pairs of conduits communicating with said interior conduits and separate pairs of conduits communicating with said exterior conduits.

3. A construction in accordance with claim 1 wherein the cross-sectional area of the interior passage defined by the tapered conduits is substantially the same at different points along the length of the tapered conduits.

4. A construction in accordance with claim 1 wherein said refrigerating means comprise coils disposed in passage means defined by said lower act of conduits.

5. A construction in accordance with claim 1 wherein said passages are lined with thin sheets of material characterized by high heat conductivity.

6. A construction in accordance with claim 1 including U- shaped structural members for supporting the walls and passage means of said enclosure, said U-shaped members comprising upper and lower, substantially horizontally disposed legs, and an intermediate substantially vertically disposed section, said legs and said intermediate section defining the interior configuration of the enclosure.

7. A construction in accordance with claim 6 wherein said structural members are located at least at either end of said enclosure, and including an inner liner attached to said structural members and extending across the enclosure for defining the inner walls of the enclosure.

8. A construction in accordance with claim 6 including vertically disposed legs secured to said structural members and extending downwardly to a support for said enclosure whereby all of the load carried by the structural members is transmitted to said vertical legs.

9. In a construction comprising a refrigerated enclosure including refrigerating means, circulating means for driving air into contact with said refrigerating means and passage means for directing the refrigerated air whereby the interior of said enclosure is adapted to be cooled, the improvement wherein said refrigerating means are disposed in a portion of said passage means, said refrigerating means comprising a plurality of elongated tubular members situated in side-by-side relationship and extending along said passage means in the direction of air flow, and manifold means extending crosswise of the passage means for interconnecting the ends of said tubular members, said tubular members comprising a plurality of adjacent sets with each set including vertically spaced apart members, and including vertically disposed plates attached at the side of the tubular members in each set, said plates being pierced to form a plurality of perforations, and said perforations defining jagged edges serving as points for the collection of frost.

10. A construction in accordance with Claim 9 wherein the passage means confining said tubular members taper from a narrow end to a wider end portion, and wherein said tubular members fan outwardly from a closely spaced relationship at said narrow end to a more widely spaced relationship at said wider end.

11. A construction in accordance with Claim 10 wherein said inner and outer wall members define a U-shaped cross section, and including U-shaped structural members associated with said inner wall member whereby the structural members become integrated with the material forming the refrigerated enclosure during a molding operation.

12. In a construction comprising a refrigerated enclosure including refrigerating means, circulating means for driving air into contact with said refrigerating means, and passage means for directing the refrigerated air whereby the interior of said enclosure is adapted to be cooled, said refrigerating means being disposed in a portion of said passage means and comprising a plurality of elongated interconnected tubular members in side-by-side relationship and a plurality of plates attached to said tubular members, the improvement wherein said plates have jagged means projecting therefrom into the path of air flow for collection of frost thereon.

13. The construction in claim 12 wherein said plates have a plurality of perforations with jagged protruding edges fonning said jagged means.

14. The construction in claim 12 wherein said refrigerating means, circulating means, and passage means are arranged to recirculate refrigerated air through said refrigerating means.

15. The construction in claim 14 comprising a food display case including an access opening arranged cooperatively with said passage means to cause the refrigerated air to flow across said access opening and return to said refrigerating means where frost is collected on said jagged means.

Claims (15)

1. In a construction comprising a refrigeratEd enclosure defining an open side for access to the interior of the construction, at least two air inlet means and corresponding outlet nozzles extending in side-by-side relationship across opposite edges of said open side, passages communicating the respective nozzles and inlets, circulating means operating to drive separate air streams through said passages and across said access opening, and refrigerating means located for refrigerating at least the innermost stream crossing said access opening, the improvement wherein said passage means includes a lower set of substantially horizontally disposed conduits for receiving air from said inlet means, substantially vertically disposed conduits communicating with said horizontally disposed sections, and an upper set of substantially horizontally disposed conduits for passing air from the vertical sections to said nozzles, at least said upper conduits having a tapered shape with one end adjacent said nozzles defining a relatively long and narrow mouth substantially coextensive with said nozzles, and with the other end adjacent said vertically disposed sections defining a relatively short and wide mouth for connection with said vertical sections.

2. A construction in accordance with claim 1 wherein said vertical conduits include at least two interior conduits disposed in side-by-side relationship, and at least two exterior conduits on opposite sides of said interior conduits, and wherein said horizontally disposed sections comprise pairs of conduits communicating with said interior conduits and separate pairs of conduits communicating with said exterior conduits.

3. A construction in accordance with claim 1 wherein the cross-sectional area of the interior passage defined by the tapered conduits is substantially the same at different points along the length of the tapered conduits.

4. A construction in accordance with claim 1 wherein said refrigerating means comprise coils disposed in passage means defined by said lower set of conduits.

5. A construction in accordance with claim 1 wherein said passages are lined with thin sheets of material characterized by high heat conductivity.

6. A construction in accordance with claim 1 including U-shaped structural members for supporting the walls and passage means of said enclosure, said U-shaped members comprising upper and lower, substantially horizontally disposed legs, and an intermediate substantially vertically disposed section, said legs and said intermediate section defining the interior configuration of the enclosure.

7. A construction in accordance with claim 6 wherein said structural members are located at least at either end of said enclosure, and including an inner liner attached to said structural members and extending across the enclosure for defining the inner walls of the enclosure.

8. A construction in accordance with claim 6 including vertically disposed legs secured to said structural members and extending downwardly to a support for said enclosure whereby all of the load carried by the structural members is transmitted to said vertical legs.

9. In a construction comprising a refrigerated enclosure including refrigerating means, circulating means for driving air into contact with said refrigerating means and passage means for directing the refrigerated air whereby the interior of said enclosure is adapted to be cooled, the improvement wherein said refrigerating means are disposed in a portion of said passage means, said refrigerating means comprising a plurality of elongated tubular members situated in side-by-side relationship and extending along said passage means in the direction of air flow, and manifold means extending crosswise of the passage means for interconnecting the ends of said tubular members, said tubular members comprising a plurality of adjacent sets with each set including vertically spaced apart members, and including vertically disposed plates attached at the side of the tubular members in each set, said plates being pierced to foRm a plurality of perforations, and said perforations defining jagged edges serving as points for the collection of frost.

10. A construction in accordance with Claim 9 wherein the passage means confining said tubular members taper from a narrow end to a wider end portion, and wherein said tubular members fan outwardly from a closely spaced relationship at said narrow end to a more widely spaced relationship at said wider end.

11. A construction in accordance with Claim 10 wherein said inner and outer wall members define a U-shaped cross section, and including U-shaped structural members associated with said inner wall member whereby the structural members become integrated with the material forming the refrigerated enclosure during a molding operation.

12. In a construction comprising a refrigerated enclosure including refrigerating means, circulating means for driving air into contact with said refrigerating means, and passage means for directing the refrigerated air whereby the interior of said enclosure is adapted to be cooled, said refrigerating means being disposed in a portion of said passage means and comprising a plurality of elongated interconnected tubular members in side-by-side relationship and a plurality of plates attached to said tubular members, the improvement wherein said plates have jagged means projecting therefrom into the path of air flow for collection of frost thereon.

13. The construction in claim 12 wherein said plates have a plurality of perforations with jagged protruding edges forming said jagged means.

14. The construction in claim 12 wherein said refrigerating means, circulating means, and passage means are arranged to recirculate refrigerated air through said refrigerating means.

15. The construction in claim 14 comprising a food display case including an access opening arranged cooperatively with said passage means to cause the refrigerated air to flow across said access opening and return to said refrigerating means where frost is collected on said jagged means.

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