Supports: cabinet structure – Spaced insulated wall – Refrigerator cabinet
Reexamination Certificate
2000-05-10
2001-04-17
Cuomo, Peter M. (Department: 3636)
Supports: cabinet structure
Spaced insulated wall
Refrigerator cabinet
C052S788100
Reexamination Certificate
active
06217140
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a heat-insulated wall having two covering layers, which are configured to be substantially vacuum-tight, and are disposed at a distance from one another. The two covering layers are connected to one another by a connecting profile (which runs along their contour and is configured with an essentially U-shaped cross-section). The two covering layers together with the connecting profile, enclose an intermediate space which can be evacuated and filled with an evacuable heat insulating material.
In the case of heat-insulated walls and housings which are based on vacuum insulation technology, and as are used, for example, in the case of domestic appliances such as refrigerators and freezers, metallic materials, for example stainless-steel sheeting, are used as the outer covering layers for the walls and housings, owing to the requirement for long-term diffusion sealing. For reasons of diffusion sealing, metallic connecting profiles are once again used to connect the two outer covering layers and are welded to the outer covering layers in a diffusion-proof manner. In this case, in addition to thin sheet-metal strips, connecting elements formed from thin sheeting and constructed with a cross section like a U-profile are also used as connecting profiles. The material thickness of the connecting elements is in all locations in the same order of magnitude as the material thickness of the outer covering layers, in order to make it possible to ensure the necessary process reliability in the manufacturing sequence of the heat-insulated wall. However, owing to their thermal conductivity, connecting elements having such a material thickness result in the thermal conductivity of the heat-insulated wall rising. Such a rise is relatively unproblematic if glass-fiber panels are used as the filling materials for the heat-insulated walls since, owing to their characteristics, such panels allow the insulating walls to have an extremely low thermal conductivity. However, at the same time, the use of glass-fiber panels results in the manufacturing costs for the heat-insulated walls being relatively high, owing to the costs of the glass-fiber panels. Furthermore, owing to their relatively high density, the use of glass-fiber panels results in the heat-insulated walls and housings filled with them being difficult to handle. Not only is the handling difficult during the production and completion to form a refrigerator but, in the end, also for the end user, owing to the weight resulting from them. However, other available supporting materials, such as open-cell polyurethane foam or polystyrene foam which do not have the disadvantageous characteristics of the glass-fiber panels are unsuitable for use as a filling material for heat-insulated walls owing to the low thermal conductivity which can be achieved with their use in conjunction with the connecting profiles that are now available, since the rise in the thermal conductivity caused by the use of such connecting profiles for the heat-insulated wall reaches an order of magnitude that is virtually impractical for use in refrigerators.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a heat-insulated wall that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which has simple constructional measures.
With the foregoing and other objects in view there is provided, in accordance with the invention, a heat-insulated wall, including: a connecting profile having a U-shaped cross-section, two limbs each with a given material thickness, and a base configured as a sheet connecting the two limbs; an evacuable heat-insulating material; and two covering layers disposed at a distance from one another and connected to each other by the connecting profile in an at least substantially vacuum-tight manner, the two covering layers together with the connecting profile enclosing an intermediate space that can be evacuated and filled with the evacuable heat-insulating material, the two covering layers each having a material thickness substantially the same order of magnitude as the given material thickness of the two limbs.
The object is achieved according to the invention by the fact that the U-shaped connecting profile is equipped with limbs whose material thickness is at least approximately in the same order of magnitude as the material thickness of the covering layers. The connecting profile also has a base that connects the two limbs and is configured like a sheet.
The connecting profile as claimed in the invention with its limbs that has thick walls in comparison to its base allows, with minimized thermal conduction, not only the use of robust clamping devices, without any problems during manufacture, for fixing the connecting profile with respect to the outer thin sheeting covering layers, but also simplifies the capability to join the connecting profile to the covering layers. Furthermore, owing to the fact that the material thickness of the limbs is in the same region as the material thickness of the covering layers, it is possible to use beam-welding processes with a high degree of process reliability. Which in turn allows a high process rate (for example about 10 m/min or more), for example by using a laser-beam welding process, as a result of which the manufacturing costs for a heat-insulated wall or a heat-insulated housing are considerably reduced. Furthermore, the connecting profile according to the invention makes it possible to use costeffective heat-insulation materials, such as open-pore polyurethane foam or open-cell polystyrene foam as a supporting body without, in the process, changing the thermal conductivity of the insulating wall to an order of magnitude which will be completely impractical for use in refrigerators.
The connecting profile on the one hand and the covering layers of the heat-insulated walls on the other hand can be produced to be particularly diffusion-resistant on the one hand and be particularly dimensionally stable on the other hand if, as is provided according to a preferred embodiment of the subject matter of the invention, the connecting profile and the covering layers are formed from stainless steel or corrosion-protected steel.
A further preferred embodiment of the subject matter of the invention provides for the limbs and the base of the connecting profile to be configured as separate individual parts, which are joined together by welding to form the connecting profile.
Such a solution offers the capability, depending on the application of the heat-insulating wall, to combine various material thicknesses for the base, configured like a sheet, with various material thicknesses for the limbs of the connecting profile. Furthermore, it is also possible to use base elements that have different profiles, reduce the thermal conductivity and can be profiled particularly cost-effectively as individual parts. In addition, the use of welding to connect the individual parts between the limbs and the sheet-like base, which is thinner than the limbs, results in an integral material joint which gives the connecting profile a certain stiffness. As a result of which the connecting profile can be handled without any problems in mass production.
A particularly high process rate for the production of the connecting profile is obtained if, according to a next preferred embodiment of the subject matter of the invention, the welded connection between the limbs and the base is produced by a beam-welding process.
The use of such a welding process allows the amount of energy required to melt the connection profile to be metered exactly so that only the connecting zone and its immediate vicinity are melted thus avoiding damage, for example from overheating, particularly on the sheet-like base.
The base and the limbs of the U-shaped connecting profile are welded particularly reliably over the entire joint length without any welding faults if, according to a next preferred embodiment of the subject matter
Hirath Jurgen
Schutte Markus
Anderson Jerry A.
BSH Bosch und Siemens Haus-geraete GmbH
Cuomo Peter M.
Greenberg Laurence A.
Lerner Herbert L.
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