Full vacuum heat insulation box body and method for producing and disassembling the same

a technology of full vacuum and heat insulation box, which is applied in the field of full vacuum heat insulation box body and method for producing and disassembling the same, can solve the problems of ozone layer destruction, clearly inferior heat insulation property of such urethane foam, 19 to 20 mw/mk, etc., and achieves the effect of reducing the degree of vacuum, facilitating the acquisition of tight wall surfaces, and improving working efficiency

Inactive Publication Date: 2001-10-25
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0035] A technical object of the present invention is to entirely hold the inside of heat insulation walls in a vacuum state as well as to provide easy evacuation, light-weight and uniform strength, reduction of remaining gas and prevention of entrance of gas from the outside, and also to facilitate disassembling after scrapping of the heat insulation walls so as to simplify recycling of respective members.
[0036] In order to achieve the above object, according to one aspect of the present invention, a full vacuum heat insulation box body in which the inside of its heat insulation walls is filled with structural materials having continuous pores and kept in a vacuum state, is constructed such that inner and outer boxes constituting a shell of the heat insulation box body and the structural material put between the inner and outer boxes are held only by close-contact caused by means of a vacuum. With this configuration, the constituent materials of the box body can be separated and collected easily when disassembling the box body after scrapping, without leaving material on the abutting parts.
[0037] Preferably, the shell of the heat insulation box body has an uneven surface, and the structural materials abutting on the uneven surface of the shell include moldings formed of a pulverized resin foam. With this configuration, a non-filling portion is not produced between the uneven surface of, for example, the inner box and the abutting surface of the structural materials, so that flaws in design characteristic such as surface deformation can be prevented even in the case where the inside of the shell is kept in a vacuum.

Problems solved by technology

It has been found that the chlorine containing 1,1-dichloro-1-fluoroethane (HFC141b), which is one of hydrochlorofluorocarbons that has been used as a foaming agent for forming urethane foam used as a heat insulating material herein, is a cause of ozone layer destruction.
However, the heat insulating property of such urethane foam is in a range from 19 to 20 mw / MK and clearly inferior to the heat insulating property of 16 mw / MK of chlorofluorocarbons used before issue of regulations on use of ozone layer destruction substances.
However, in the cases that the packing material has some fine defect which is larger than expected, a part of the packing material is destroyed by an external factor or a large amount of volatile substance remains in or sticks to the core material, thereby creating a number of possibilities that a desired heat insulating property cannot be provided.
Therefore, if the aforementioned failure occurs in the vacuum heat insulation panel, it is not only very difficult to repair the vacuum heat insulation panel but also impossible to replace the vacuum heat insulation panel with a new one.
In the conventional heat insulation box body configured so that all the heat insulation wall is kept in a vacuum state as described above, it has been found that it is very difficult to fill the inside of the shell with a powder or granular substance uniformly and densely when the powder or granular substance is put in the shell.
Accordingly, if the inside of the shell is kept in a vacuum state, the shell is pressed by atmospheric pressure so as to be partly or wholly contracted, so that deterioration of design characteristic may be caused or in some cases, deterioration of heat insulating property caused by reduction of the wall thickness may be triggered.
Further, in filling a heat insulation box body having inferior filling property such as a large-size refrigerator, or the like, a larger amount of filling is required than the amount of filling corresponding to the density for obtaining a strength required to prevent deformation caused by the atmospheric pressure.
Accordingly, there arise disadvantages such as economical loss, increase of weight, lowering of heat insulating property, etc.
Further, in filling the heat insulation box body with open-cell foaming urethane, communication of bubbles cannot be sufficiently achieved so that closed cells remain, if bubbles in a foamed state flow over a short distance from the start point of foaming, bubbles flow in a state of stable shape after completion of bubble growth, and so on.
Accordingly, if this is used as it is, for a structural material, there arises a disadvantage that not only a long time is required for evacuation particularly of a large-size full vacuum heat insulation box body but also a degree of vacuum changes is lost over the passage of time.
Furthermore, in a state where the inside of the shell is filled with no gap, a long evacuation time is required because this structure brings a great disadvantage for sucking remaining gas in an opposite portion inside the shell to the gas-exhaust hole up to all open cells through a long distance along open cells by use of a vacuum pump from a gas-exhaust hole provided in an end portion of the heat insulation box body such as a refrigerator, or the like, to thereby perform evacuation to secure a sufficient vacuum state.
Further, during the period when the degree of vacuum drops with the passage of time, a cooling operation is carried out frequently, so that electric power is additionally consumed and the temperature of the inside of the refrigerator becomes unstable to cause a problem in that the freshness of foods is affected.
Further, when the full vacuum heat insulation box body obtained by the conventional production method is to be disassembled after scrapping so as to recycle parts or members, some measures are required to prevent scattering of the filling materials at the time of disassembling or collecting in the former case of filling powder or granular materials, and it is also difficult to handle the materials without damage even in the case of employing a method in which the filling materials are disposed in a form protected by bags, or the like.
It is however impossible to perfectly separate the urethane foam self-adhering to the inner and outer boxes from adhering surfaces.
Accordingly, used members cannot be reused and therefore, recycling of the members is difficult using the conventional methods.

Method used

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  • Full vacuum heat insulation box body and method for producing and disassembling the same
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  • Full vacuum heat insulation box body and method for producing and disassembling the same

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embodiment 1

[0076] Embodiment 1

[0077] The present invention will be described below on the basis of an embodiment as shown in the drawings.

[0078] As shown in FIG. 1, the full vacuum heat insulation box body in this embodiment is applied to a chest freezer and so designed that inner and outer boxes 22 and 23 which constitute a shell 21 of the heat insulation box body and structural materials with continuous pores 24, 25, 26 and 35 which are interposed between the inner and outer boxes 22 and 23 and are preserved only by close contact based on a vacuum.

[0079] In more detail, a box-like member formed by stainless steel thin plates welded or jointed with bond is used herein as the inner box 22 constituting an interior surface of the shell 21. The material of this member is selected taking such conditions into consideration as suppression of lowering of heat insulating property caused by propagation of heat from the outer box 23 constituting an exterior surface of the shell 21, a gas barrier propert...

embodiment 2

[0099] Embodiment 2

[0100] Referring now to FIG. 6 through FIG. 8, with respect to the inside of the circumferential side walls, only left and right walls are shown and explained.

[0101] In this embodiment, the full vacuum heat insulation box body is applied to a chest freezer. Parts of structural materials 24 and 25 inserted in side walls of a shell 21 constituted by outer and inner boxes 23 and 22 and a plate member 27, that is, parts 24a, 24b, 25a and 25b each produced by cutting a large slab-like foamed article formed from a foaming resin such as foaming urethane, or the like, having open cells and exhibiting a triangular sectional structure are so designed that a plurality of grooves 41 extending in the lengthwise direction as shown in FIG. 8 are provided in parallel on an inclined surfaces of either one of the inner part 24a and the outer part 24b, or 25a and 25b. The grooves are herein provided on the inclined surfaces of the inner parts 24b and 25b disposed on the inner box 22...

embodiment 3

[0105] Embodiment 3

[0106] In the full vacuum heat insulation box body according to this embodiment, the present invention is applied to the same chest freezer as in the first embodiment. Among the structural materials 24, 25, 26 and 35 inserted in the inside of the shell 21 constituted by the outer and inner boxes 23 and 22 and the plate member 27 in FIG. 1, at least parts 24a, 24b, 25a, 25b, 35a and 35b exhibiting a triangular sectional structure are formed of polystyrene foam having open cells. Incidentally, FIGS. 1, 2, 3 and 7 explained previously are referred to in the following description.

[0107] In this embodiment, a resin foam having open cells is used as a material for the structural materials 24, 25, 26 and 35. As a material, polystyrene foam having small cell size are used as well as urethane foam. With respect to a method for producing polystyrene foam having open cells, as described in WO96 / 07942 (JP-A-8-503720, Japanese Patent Application No. Hei-6-509062) and WO96 / 1687...

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Abstract

A heat insulation box body includes inner and outer boxes forming a shell of the heat insulation box body and triangular structural materials inserted in the shell held by close-contact by means of a vacuum. Further, at the time of disassembling the heat insulation box body after scrapping, a shell surface is cut and air is introduced into the inside of the shell to return the state of the shell to an atmospheric pressure state and then respective members are separated from each other.

Description

BACKGROUND OF THE INVENTION[0001] 1. Field of the Invention[0002] The present invention relates to heat insulation walls requiring heat insulation in a heat insulation box body such as a refrigerator, or the like, in which wall surfaces are formed of thin metal plates, resin moldings, or the like. More particularly, the present invention relates to a full vacuum heat insulation box body in which porous structural materials are disposed in a shell constituting heat insulation walls for the purpose of preventing deformation so that a vacuum is kept, a refrigerator using such a full vacuum heat insulation box body, a method for producing such a full vacuum heat insulation box body, and a method for disassembling such a full vacuum heat insulation box body.[0003] 2. Description of the Related Art[0004] Conventionally, a shell of a refrigerator, or the like, is so constituted that an outer box is formed of a thin metal plate such as an iron plate, an inner box is formed of a resin moldin...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): B65D81/38B29C39/10B29C44/12B32B1/00B32B5/18F25D23/06
CPCB29C44/1242F25D23/062F25D2201/1262F25D2201/14Y10T428/231Y10S62/13Y10S29/044Y10T29/49359F25D2400/04F25D23/02
InventorNISHIMOTO, YOSHIO
OwnerMITSUBISHI ELECTRIC CORP