Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from European Patent Application No. 98610027.9 filed Aug. 17, 1998. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an insulating cover for open cooling devices, such as refrigerators or deep freezers generally used in stores and supermarkets. In numerous cases refrigerators or deep freezers will not be covered over a longer period of time, e.g. stores selling products that need cooling to maintain freshness, rely on open refrigerators and deep freezers to provide easy accesses for the customers to the produce. However, in the closing hours of these stores the energy consumption can be greatly reduced by applying insulating covers to the openings of these cooling devices. 
     2. Description of the Prior Art 
     The conventional technique, used for reducing the energy consumption of cooling devices in the closing hours of stores and supermarkets, applies insulating covers to the openings of refrigerators or deep freezers. Chest refrigerators or chest deep freezers are conventionally covered by self-supporting insulating covers, supported by the edges of the chest refrigerator or chest deep freezer. The conventional self-supporting insulating cover as described in DK patent no.:152602, to which reference hereby is made. 
     The conventional insulating cover comprises two plastic foils joined at the circumferentially outer rim providing an enclosure for the insertion of insulating material. Rods or beams are mounted to the cover to constitute a self-supporting effect of the insulating cover, however the rods or beam increase the weight of the insulating cover. The rods&#39; or beams&#39; overall weight contribution to the total weight of the insulating cover is considerable compared to of any of the parts included in the cover. 
     Experience from using conventional technique shows that usage of the conventional insulating cover on top of cooling devices, renders it necessary to insure the insulating material from moving within the enclosure thereby reducing the overall insulating effect of the cover. Therefor a type of fixation is needed to avoid shifting, to any substantial extent, of the insulating material. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an easy to handle, durable self-supporting insulating cover having an overall polygonal, semi-circular, circular, semi-elliptic, elliptic or any of above combinatory shape with an improved stiffness and support of the insulating cover. 
     A feature of the present invention originates from the fact that stitching through the insulating cover insuring the enclosed insulating material from concentrating at any particular areas of the insulating cover can be avoided. This is particularly advantageous because by avoiding through-stitches, thermal bridges between air inside the cooling device and outside the cooling device are eliminated, and by insuring a stable insulating material without through-stitches an enhanced insulation is achieved. 
     A particular advantage of the present invention relates to the lighter structure of the insulating cover, which renders it easy to handle and carry the insulating cover and therefore provides a more manageable and mobile insulating cover. 
     The above object, feature and advantage together with numerous other objects, features and advantages, which will be evident from the below detailed description of preferred embodiments of the insulating cover according to the present invention, comprising: 
     (a) a gas and water impermeable first foil and defining a first circumferential outer rim, 
     (b) a gas and water impermeable second foil substantially coextensive with said first foil and defining a second circumferential outer rim, said first and second foil being joined together at said first and second outer circumferential rims of said first and second foils, defining an enclosure between said first and second foils, 
     (c) a body of insulating material inserted in said enclosure, and 
     (d) a plurality of supporting tubular elements in co-planar relationship with said first and second foil providing stiffness of said insulating cover in axial direction of said plurality of supporting tubular elements and flexibility of said insulating cover in a direction perpendicular to said axial direction, said plurality of supporting tubular elements having a weight constituting at a maximum 30% of the total weight of the insulating cover, such as a weight within the range of 5% to 25%, preferably 10% to 20% of the total weight. 
     Using a plurality of supporting tubular elements constitutes a significant reduction of the overall total weight of the insulating covers compared with the conventional covers. This fact insures an easy to handle, manageable and therefore more mobile construction, which reduces the time spend on the application and removal of the insulating covers. Furthermore the plurality of supporting tubular elements provides a greater stiffness of the cover in the axial direction compared to conventional covers using rods or beams, hence constituting a smoother surface of the insulating cover minimising any shifting or slipping of the insulating material inside the insulating cover. Finally the smoother surface reduces the material from concentrating at any particular area of the cover and therefor eliminates the need for through-stitches to fixate the insulating material. 
     The plurality of supporting tubular elements can have an overall length in the axial direction concordant with length of an insulating cover in that same direction, alternatively the plurality of supporting tubular elements can have an overall length in the axial direction longer than the length of the insulating cover in that same direction, or, finally, the plurality of supporting tubular elements can have an overall length in the axial direction shorter than the length of the insulating cover in that same direction thereby providing the insulating cover with a flexible extenuation allowing the insulating cover to fold about an edge of a cooling device. 
     The plurality of supporting tubular elements can be fixed to one of the outer surfaces of said first or second foils, or it can be fixed in said enclosure. The plurality of supporting tubular elements can be fixed to said first and/or second foils by gluing, welding, stitching or combinations thereof. Stitching can involve stitching a plurality of bands onto the outer surfaces of first or second foils with two parallel series of stitches leaving a space between them for the insertion of one supporting tubular element in each said space. This wide variety of options allows insulating covers according to the present invention to fulfill numerous of customized solutions and designs to optimized for an enhanced insulation. 
     The body of insulating material can comprise mineral fibers, plastic fibers, plastic filaments, partly coherent foam spheres, fully coherent foam spheres, any other insulating materials or combinations thereof An embodiment according to the present invention can comprise a body of fully coherent insulating material defining a sheet structure with a circumferentially outer rim. The application of a sheet of insulating material can insure against fibers evading the enclosure, and therefor increase the life span of the insulating cover. 
     The body of insulating material can be loosely inserted into the enclosure, or it can be fixed in the enclosure by gluing, welding, stitching or any combinations thereof the insulating material to said first and/or second foils. When applying a body of fully coherent insulating material it can be fixed at the circumferentially outer rim of said first and/or second foils by gluing, welding, stitching or any combinations thereof. The first and second foils can be joined at their outer circumferential rims by stitching through a band folded about outer surfaces at said outer circumferential rims of said first and second foils and the circumferentially outer rim of said body of insulating material situated in said enclosure. The latter technique constitutes the possible reduction of production steps and therefor reduction of the production costs. 
     The insulating cover can have an overall polygonal shape, such as rectangular, trapezoidal, parallelogram, triangular, hexagonal, semi-hexagonal or an overall circular, semi-circular, elliptic, semi-elliptic or any combinations thereof, providing a large variety of shapes of insulating covers of the present invention that can fulfill insulating purposes for a substantial amount of types of cooling devices. 
     The plurality supporting tubular elements can have an individual supporting tubular element orientated substantially perpendicular to said circumferential outer rim or defining a specific angle with said circumferential outer rim. This feature insures that an optimum support and smooth surface is achieved. 
     An overall rectangular shaped insulating cover can comprise a multiple of individual modules of insulating covers linked together to form said overall rectangular insulating cover, and an overall hexagonal, circular or elliptic shaped insulating cover can comprise two corresponding semi-hexagonal semi-circular or semi-elliptic shaped individual modules of insulating covers linked together to form said insulating cover. The linking of multiple modules of insulating covers can be permanent or detachable through linking mechanisms such as tape, zippers, buttons, Velcro, magnets or any combinations thereof. The multiple of modules of insulating covers defining a first end of an individual module of insulating cover having a first part of said locking mechanism placed on a first surface of said individual module of insulating cover and a second end of said individual module of insulating cover having a second part of said locking mechanism placed on a second surface of said individual module of insulating cover, multiple modules can be linked through second end of a first module to first end of a second module thereby constituting an overlapping of modules constituting an insulating cover. This feature gives tremendous possibilities for using the cover on top of various cooling devices, furthermore the modular construction will enhance the easy handling and mobility of the insulating cover. 
     The insulating cover can have dimensions of an area from 0.45 m 2  to 50 m 2  typical areas being 1.4 m 2 , 2.7 m 2 , 4.1 m 2  and 5.4 m 2 , a thickness from 5 mm to 50 mm typical thickness&#39; being 10 mm. Due to the modular features of the present invention the area an insulating cover made according to present invention can assume a significant variety of sizes of areas. 
     The impermeable first foil can have perforations systematically situated such as to drain accumulated condensed water from said insulating cover. The insulating cover can be arranged on a cooling device having said outer surface of first foil facing the cooling device. This drains any accumulated condensed water from the interior of the insulating and allows the insulating cover to be aired hence allowing vapour to evade the interior. 
     The first and second foils of the insulating cover can be of impermeable materials e.g. polymers or plastic foil such as PE, PP, PVC or any other types of plastic foils, or metal sheets such as aluminum foil, or any combinations thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be further described with reference to the drawings, in which 
     FIG. 1 is a schematic illustration of a cooling device covered by a first and presently preferred embodiment of a rectangular insulating cover according to the present invention. 
     FIG. 2 is a schematic illustration of a magnified section of the first embodiment of the insulating cover also shown in FIG. 1, having a section removed thereby revealing the interior of the cover. 
     FIG. 3 is a schematic illustration of a section of a second or alternative embodiment of the insulating cover defining an overall semi-hexagonal configuration. 
     FIG. 4 is a schematic illustration of a magnified section of one of the corners of a modified second or alternative embodiment of the insulating cover defining a semihexagonal embodiment, having a section removed thereby revealing the interior of the cover. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, a cooling device, designated by the reference numeral  10  in it&#39;s entirety, being e.g. a chest refrigerator or a chest deep freezer, has two parallel square end walls  12  mounted together with two parallel rectangular side walls  16  with the adjoining walls at right angles to each other. A bottom piece  14  is completing the shape of an open box, allowing for access through the uncovered top to cooled produce  18  arranged within. Fresh meat, dairy products, poultry and fish, or frozen vegetables, ice-cream, precooked dinners or any combinations thereof are examples of the produce  18 , but the cooling device  10  can also contain biological products, biological specimens, microbiological cultures, medicine, pharmaceutical products, medical instruments or any combinations thereof. In its entirety the edge of the walls facing away from the bottom piece  14  of the cooling device  10  has a thickness defined by a for refrigerators or freezers typical insulating material being either a single layer, a double layer or a composite of materials, e.g. mineral fibers, PU foam or any other insulating material or combinations thereof, enclosed in sheets of metal e.g. aluminum, zinc, steel, iron, or sheets of plastic materials or glass, or any combinations thereof. The thickness of the walls is providing a top surface  11  for the possible resting, strapping, Velcro-locking, buttoning or magnetic holding of an insulating cover, designated by the reference numeral  15  in it&#39;s entirety, onto the cooling device  10 . 
     The cooling device  10  can have the dimensions: width from 0.5 m to 2.5 m, length from 1 m to 20 m and depth 0.5 m to 1 m, having typical dimensions: width 0.9 m, length 1.5 m and depth 0.75 m. The top surface  11  of the cooling device  10  can be slanting up to 45° with respect to the horizontal plane. 
     The insulating cover  15  comprising an outer impermeable foil  13  and an inner impermeable foil  26  can additionally be extended in an outward direction and folded down onto the outward facing surfaces of the walls of the cooling device  10  hereby obtaining a good insulation. 
     The insulating cover  15  can be fitted any cooling device  10  either by one full size cover matching the dimensions of the cooling device  10 , or it can be fitted any cooling device  10  by constructing a insulating cover  15  from any multiple of modules of insulating covers  15 . The modules can be permanently linked together or be detachable. The separation of linked insulating cover  15  modules can be conducted through linking mechanisms like tape, zippers, buttons, Velcro, magnets or any combinations thereof. The linking mechanisms can be situated such that two edges of modules overlap one another, hence recovering full insulating effect. This can effectively be done by having one part of the linking mechanism on the outer surface of a module and the second part of said linking mechanism on the inner surface of an adjoining module 
     The insulating cover  15  of the present invention is a flexible self-supporting construction supported by the top surface  11 , defined by the walls of the cooling device  10 . The flexibility of the insulating cover  15  allows the cover to be rolled into a cylindrical shape, hence reducing the required storage space for the insulating cover  15 . An advantage of the modular constructed insulating cover  15  can be that the handling of the cover and the storage possibilities of the cover are considerably improved. 
     In the present context, terms, such as inner, outer, bottom and top, relate to the space confined inside the cooling device  10 . An inner surface of an object is facing the confined space, all other surfaces of said object are outer surfaces. The term bottom is the part of the cooling device  10  resting on the floor furthermore comprising an inner surface perpendicular to all the inner surfaces of the walls of the cooling device  10 . The term top is the part of the cooling device  10 , through which access to the confined space is achieved, and further comprising the edges of the walls. Terms such as inward and outward are terms describing surface directions. An inward facing surface is relating to a surface of for example a foil, which is facing an interior space. Outward is relating to the surface facing away from an interior space. The interior of the insulating cover  15  is further described in detail with reference to FIG.  2 . 
     FIG. 2 is illustrating a magnified section of the insulating cover  15 , with a section cut away to reveal the interior. Insulating material  24 , such as mineral fibers, plastic fibers, plastic filaments, partly coherent foam spheres, fully coherent foam spheres, any other insulating materials or combinations thereof, is positioned between the outer impermeable foil  13  and the inner impermeable foil  26 . The insulating material  24  can be loosely inserted between the inner and outer foils or can be glued, welded or stitched onto the outer foil  13  or inner foil  26 . The presently preferred embodiment has a sheet of the insulating material  24  fixed between the outer foil  13  and inner foil  26  by gluing, welding or preferably stitching a band  22 , folded about the edges of the sheet of the insulating material  24 , the inner foil  26  and the outer foil  13  at the full circumference of the insulating cover  15 . The inner foil  26  has systematically placed perforations  28   a-l  enabling the possibility for airing the insulating material  24  and hence significantly reducing the amount of condensed water accumulating in the insulating material  24 . Furthermore having the perforations  28   a-l  on the inner foil  26  the accumulated condensed water is drained out of the insulating cover  15 . 
     A supporting tubular element  20  can be mounted on the outward facing surfaces of the inner or outer foils  26 , 13 , or can be placed in the space between the insulating material  24  and the inward facing surfaces of the inner foil  26  or the outer foil  13 , and can be fixed to either inward or outward facing surfaces by gluing, welding or stitching. FIG. 2 is showing the supporting tubular element  20  between the inward facing surface of the inner foil  26  and the insulating material  24  and fixed by stitches  23  through the inner foil  26 . 
     In a rectangular shaped insulating cover  15 , as shown in FIGS. 1 and 2, a number of parallel supporting tubular elements  20  are inserted into the insulating cover  15  creating a low weight, stiff and self-supporting cover. When the insulating cover  15  is supported by the top surface  11  of the cooling device  10 , the supporting tubular elements  20  create a smooth surface of the insulating cover  15  minimising any shifting or slipping of the insulating material  24  inside the insulating cover  15 , while maintaining the possibility for rolling the cover together about an axis parallel to the supporting tubular elements  20 . 
     A feature of using the supporting tubular elements  20  is, stitching through the insulating cover  15  insuring the insulating material  24  from concentrating at any particular areas of the insulating cover  15  can be avoided. This is particularly advantageous because by avoiding through-stitches, thermal bridges between air inside the cooling device  10  and outside the cooling device  10  are eliminated, and by insuring a stable insulating material  24  without through-stitches an enhanced insulation is achieved. 
     By implementing supporting tubular elements  20  instead of supporting rods a greater stiffness of the insulating cover  15  is obtained, while the weight of the insulating cover  15  is reduced making the mobility of the insulating cover  15  more manageable. 
     A second or alternative embodiment according to the present invention is shown in FIGS. 3 and 4 and will in the following be further described in detail. FIG. 3 is illustrating one of two parts of an insulating cover  30  for a hexagonal shaped chest cooling device being either a refrigerator or a deep freezer. The insulating cover  30  comprises three pieces of trapezium shaped outer foils  34   a-c.  Each of the outer foils  34   a-c  can have an insulating material  42 , of any of the previously described material types, loosely inserted between inner foils  44   a-c  and the outer foils  34   a-c  or can have the insulating material  42  glued, welded or stitched on to the inward facing surface of the outer foils  34   a-c  or the inward facing surface of the inner foils  44   a-c.  The second or alternative embodiment of the present invention has a sheet of the insulating material  42  fixed between the outer foils  34   a-c  and the inner foils  44   a-c  by gluing, welding or preferably stitching bands  32   a-c  and  36   a-c,  folded about the parallel edges of the insulating material  42 , the inner foils  44   a-c  and the outer foils  34   a-c,  thereby producing three trapezium shaped sections. Bands  31   a-b  are folded about the adjoining slanting edges of the three trapezium shaped sections, such that the bands  31   a-b  are in contact with the outer foils  34   a-c  of two adjoining trapezium shaped sections. The bands  31   a-b  are stitched from the outer foil  34   a-c  through the insulating material  42  and inner foil  44   a-c  of the first trapezium shaped section, through the inner foil  44   a-c,  insulating material  42  and outer foil  34   a-c  of the second trapezium section leaving space in the bands  31   a-b  for the insertion of supporting tubular elements  40 . The two end edges of the semi-hexagonal shape are fitted with bands  38   a-b  either by gluing, welding or preferably stitching, leaving space in the bands  38   a-b  for insertion of further supporting tubular elements  40 . 
     The supporting tubular elements  40  are inserted into the space in the bands  31   a-b  and  38   a-b  giving the insulating cover  30  a smooth surface and hence achieving similar advantages as described for the first preferred embodiment of the present invention. Alternatively the supporting tubular elements  40  can be fixed onto the outward facing surface of the inner foils  44   a-c  by bands  48   a-d  sewn onto the outward facing surface of the inner foils  44   a-c,  as shown in FIG. 4, using two seems leaving a space between the seems for the insertion of the supporting tubular element  40 . 
     The inner foils  44   a-c  are systematically perforated with holes  46   a-h  hence achieving the same advantages, as the insulating cover  15  described through FIGS. 1 and 2. 
     The particular cooling device for the insulating cover  30 , shown in FIG. 3 and 4, can include a variety of hexagonal dimensions, and comprise a hexagonal surrounding wall and a hexagonal centre. The hexagonal centre being solid hence providing a supporting surface for the insulating cover  30  in conjunction with the outer walls of the cooling device. 
     The above described preferred embodiments made according to present invention can be used for a variety of purposes including extra insulating covers for upright standing open refrigerators or additional insulating or non-insulating purposes. 
     EXAMPLE 
     The preferred embodiment of the cover according to the present invention described above with reference to FIGS. 1 and 2, was made as follows. 
     The rectangular insulating cover  15  had the overall dimensions: length 1250 mm, width 910 mm, average thickness 5 mm, with 2 supporting tubular elements each having a diameter of approximately 10 mm and separated by a distance of 600 mm. The first supporting tubular  20  element placed at a distance of 325 mm from one edge of the insulating cover parallel to the axis of the supporting tubular elements and the second supporting tubular  20  element placed at a distance of 925 mm from said edge. The supporting tubular elements  20  were fixed using through-stitches  23  separated by 25 mm. 
     The outer foil was impermeable and made of the material PE and had an average thickness of 120 μm. The inner foil was impermeable and made of the same materials as the outer foil and also had an average thickness of 120 μm. The inner foil was perforated with holes  28   a-l  with a diameter of 6 mm through the inner foil at widthwise separations of 82 mm and lengthwise separations of 200 mm. The first perforation, for instance  28  h, positioned 27 mm from the edge defining the width of the insulating cover  15  and 35 mm from the edge defining the length of the insulating cover  15 . The band  22  holding the foils together was made of the material PVC, but can be any such as PE, PP or cotton, and had the width 36 mm and was folded about the edges of the two foils and a sheet of insulating material  24  and stitched with a polyester thread. The insulating material was polyester.

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