Supports: cabinet structure – Spaced insulated wall – Refrigerator cabinet
Reexamination Certificate
1997-12-01
2001-05-01
Hansen, James O. (Department: 3636)
Supports: cabinet structure
Spaced insulated wall
Refrigerator cabinet
C312S400000, C312S409000, C220S592090
Reexamination Certificate
active
06224179
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a heat-insulating housing having at least one useful housing space which is enclosed by housing walls and at least one door. The invention also relates to a household oven and a household refrigerator having a chamber with the housing.
Thermal insulation is achieved in various ways in the known prior art. In the field of household appliances, for instance, such as refrigerating appliances, ovens or the like, various insulating materials are used to insulate useful spaces. In ovens, an oven chamber that surrounds a baking space is provided with fibrous insulating materials on its outside which serves the purpose of thermal insulation, and in refrigerating appliances high-resistance foams are used for thermal insulation. The high-resistance foams are introduced in the form of liquid starting components between an outer metal housing and an inner plastic lining for joining the two together after a chemical reaction has taken place. Vacuum insulating panels are also used instead of the high-resistance foam insulation for purposes of insulation in the field of refrigerating appliances. The vacuum insulating panels are introduced into an interstice between the outer metal housing and the inner plastic lining. In that case, transitions between the individual wall portions of the heat-insulating housing of a refrigerating appliance are also filled with high-resistance plastic foam. As far as refrigerating appliances are concerned, the thermal insulation techniques which were used heretofore in the field of household appliances are disadvantageous especially in the event of recycling of the appliances, which is gaining increasing importance, since the various materials forming the heat-insulating housing are joined together into a unit by the high-resistance foam insulation, and separating the unit into its individual materials entails complicated and expensive separating processes, because of the adhesion action of the liquid foam. With regard to fibrous thermal insulating materials used in household ovens, such materials, because of their fibrous nature, are time-consuming to install in the oven chamber to be insulated and moreover involve the risk of individual fibers becoming dissolved out of the fibrous composition of the insulating material and becoming deposited at contact points of electrical function units, where they may cause problems regarding oven function because of their insulating nature.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a heat-insulating housing as well as a household oven and a household refrigerator having the housing, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type in a simple way and which at the same time make it possible to markedly improve the thermal insulating action of the housing in a simple way.
It is accordingly an object of the invention to provide a heat-insulating housing, comprising housing walls formed of two mutually spaced apart boundary walls substantially enclosing an interstice; at least one door enclosing at least one useful housing space along with the housing walls; and slabs of pressure-resistant, open-celled, evacuatable heat insulation material in a final chemical state to be introduced loose into the interstice for filling the interstice.
Through the use of this structure according to the invention, a heat-insulating housing is created which when recycled can be broken down at little technical effort and thus in an economical manner into maximally pure material components, which can thus be used in turn as technically high-quality materials. Moreover, due to the construction of the housing according to the invention an insulation process that is favorable from a production standpoint is achieved, which makes cost-intensive devices for environmental protection and for protecting the health of the production workers unnecessary. Moreover, sealing provisions of the kind previously employed to prevent the escape from refrigerating appliances of high-resistance foam insulation introduced in the form of liquid starting components, can be dispensed with. Additionally, influence on electrical appliance functions from individual insulating fibers of fibrous insulating materials that could unintentionally plug up electrical contact paths is substantially precluded.
In accordance with another feature of the invention, the boundary walls are constructed to be maximally dimensionally rigid. Through the use of the dimensionally rigid boundary walls, the thermal insulation material introduced into the interstices can be densified to improve the heat-insulating properties of the housing walls, without additionally having to support the boundary walls through the use of a supporting form.
In accordance with a further feature of the invention, the heat insulation material is formed of slabs of open-celled polymer foams. The heat insulation material, which is constructed with open cells, not only permits a substantially simpler but also a markedly greater pressure reduction in the interstice as compared with the ambient pressure of the housing walls, and at the same time, because of the dimensionally rigid boundary walls and the pressure proof insulating material, substantially flat surfaces are created, even after an evacuation of the interstice, which without further provisions can serve at the same time as visible or transparent surfaces for the housing walls.
In accordance with an added feature of the invention, the air pressure is lowered in the interstice filled with the heat insulation material as compared with the ambient pressure of the housing, and the boundary walls demarcating the interstice are formed of a material that is diffusion proof at least approximately in accordance with the pressure difference. Effective insulation for housing walls that is constant in terms of its long-term effect can be achieved through the use of such a structure.
In accordance with an additional feature of the invention, sufficiently good thermal insulation can be created if the air pressure in the interstice filled with the open-celled, pressure-proof heat insulation material is between 0.01 mbar and 100 mbar, but is preferably below 1 mbar.
In accordance with yet another feature of the invention, especially flat surfaces in an evacuated interstice between the boundary walls are obtained if the pressure-proof open-celled heat insulation material, in terms of the thickness of the material, is approximately equivalent to the spacing between the boundary walls.
In accordance with yet a further feature of the invention, especially effective thermal insulation for the housing walls, and especially effective support in the event of evacuation of the interstice, is attained for the boundary walls if the pressure-proof open-celled heat insulation material is disposed substantially over the entire surface of the housing.
In accordance with yet an added feature of the invention, the open-celled, pressure-proof heat insulation material is formed of aerogels, which are condensed constantly during the process of filling the interstice, with a density of from 80 to 300 kg/m
3
, and preferably with a density in a range from 80 to 120 kg/m
3
.
Through the use of this kind of filling of the interstice, a coefficient of thermal conductivity for the housing walls is attained having a value, even without reducing the air pressure in the interstice between the boundary walls, which is markedly below that of the insulation techniques previously used in the field of household appliances.
In accordance with yet an additional feature of the invention, the pressure-proof, open-celled heat insulation material is formed of slabs with joining aids disposed at locations at which they are connected to one another.
Through the use of this kind of insulating material that can be introduced loose into the interstice, it is assured that flat surfaces and thus satisfactory visible or transparent surfaces for the housi
Eberhardt Hans-Frieder
Wacker Wolfram
Wenning Udo
BSH Bosch und Siemens Haus-geraete GmbH
Greenberg Laurence A.
Hansen James O.
Lerner Herbert L.
Stemer Werner H.
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