DE4324996C1 - Foamfree insulation for refrigerators - Google Patents

Abstract

The foamfree insulation for refrigerators is characterised in that evacuated shaped bodies are mounted on the external container or internal container before external and internal container are interconnected, external and internal container of the refrigerator are subsequently interconnected in a gas-tight manner and the cavity formed during this is evacuated.

Description

The invention relates to a foam-free insulation for Refrigeration appliances.

Known refrigerators, such as refrigerators and freezers for the household area and refrigerators for the Leisure area, usually consist of one Sandwich housing and one or more doors, being the cavities between the inner and outer container of the Foam the housing or the door (s) with polyurethane become. The polyurethane foam has one double function: on the one hand it wears as Construction element to the mechanical stability of the device and also acts as Insulation medium to the cold losses of the device to keep low.

A description of these known constructions from Refrigerators and freezers can be found in "Textbook of Kältetechnik ", volume 2, 3rd edition, pages 862-865, C.F. Müller, Karlsruhe (1981).

The known refrigeration devices are manufactured such that the inner container by deep drawing suitable plastics, such as ABS (acrylonitrile butadiene Styrene) and PS (polystyrene). Of the Inner container generally consists of one single component, which has two side walls, a rear wall, has a top and a bottom.  

The outer container is made of suitable materials, for example painted or galvanized sheets. Parts of the outer container also consist of others Materials such as cardboard, the additional are laminated with an aluminum foil.

As components for the outer container are either flat, two-dimensional workpieces used or it become the flat, two-dimensional workpieces using suitable methods (bending, pressing) spatially arranged, three-dimensional workpieces deformed. The two- and / or three-dimensional Workpieces are made in a suitable manner, for example by screwing, riveting, soldering, welding, gluing, connected together and form the outer container, of the 2 side walls, a rear wall a top and has a floor.

The pre-assembled outer container and the inner container are initially separate, then stretched out and for example by Screw, rivet or glue together connected. The resulting cavity becomes known refrigeration devices foamed with polyurethane.

A special case is the device construction with foamed in Evaporator / condenser; here contains the Cavity also the evaporator capillary tubes (Inside of the device) and condenser (Outside of device). The manufacture of the appliance doors takes place in a similar way to the production of the Housing.  

It is known to improve the insulation effect of refrigerators and freezers in the insulation to bring in evacuated moldings. Suitable for this Evacuated moldings are for example in the German applications DE 38 28 669 A1, DE 40 29 405 A1 and DE 40 19 870 A1 (Degussa) are described.

In US 4,529,638 (Matsushita) is a evacuated molded body described within the Refrigerator cavity between the inner and outer wall in is embedded in a polyurethane foam. About Art the attachment, however, is not a statement been.

Evacuated moldings can be particularly in refrigeration devices simply before assembling the eye and inner container, that is, in the phase, in the interior and Outer container still available separately, attached become.

A procedure for attaching evacuated Moldings in refrigeration equipment is carried out by one

• - The evacuated moldings on the outer container or the inner container of the refrigerator before Outer and inner containers are connected to each other,
• - Outside and inside container of the refrigerator then connects with each other thereby foaming cavity.

The known refrigeration devices have the disadvantage that they contain polyurethane foam. When foaming, the use of a propellant gas, such as pentane, CO ₂ , fluorocarbons or the like, is necessary.

In addition to the due to the chemical properties sometimes difficult handling of propellants also the insulating effect does not have the desired effect to have.

There is therefore the task of a foam-free Find insulation for refrigerators.

The invention relates to a foam-free Insulation for refrigerators, which thereby is characterized in that evacuated moldings on the Outer container or inner container of the refrigerator are attached before the outer and inner container be connected together, outer and inner container of the refrigerator then gas-tight with each other are connected and the cavity that forms is evacuated.

In particular, the foam-free insulation in the Housing, the doors and / or the compressor niches of the Refrigerators are used.

Evacuated moldings can be used as evacuated Filler insulation boards with symmetrical or asymmetrical structure can be used.  

Silicic acid can be used as a filler for the moldings and / or silicates can be used.

The molded body can be attached by gluing with Adhesives are made using substances as adhesives can be used without chemical reaction tie off.

Hot melt adhesives or double-sided adhesive tapes are used.

The moldings can on the inside of the Outer container or on the outside of the Inner container are attached.

When attaching the moldings can additionally Spacers are introduced.

The moldings can preferably be on the inside the outside wall of the device.

As a shaped body, preferably asymmetrical Shaped body used in the Barrier film on the flat side Aluminum foil included.

The asymmetrical moldings can be attached in this way be that the flat side of the molded body on the Comes to rest on the inside of the outside wall of the device.

Several moldings can be together before installation get connected.  

Several moldings can be placed on the device wall Be attached composite.

The moldings are attached so that they either on the inside of the outer container or on the Can come to lie outside of the inner container the attachment to the inside of the outer container already on the flat, two-dimensional or even the spatially deformed, three-dimensional workpieces respectively. An attachment of the molded body on pre-assembled outer container is also possible.

The outer or inner container can be made of gas-tight and water vapor tight materials such as metals or Plastic. As an outer or inner container can be deep-drawn or gas-tight from individual parts assembled structures can be used. You can either by an adjusted material thickness or be constructed by supports so that they are in the Evacuation of the cavities should not be deformed.

After installing the outer and inner container a cavity around the volume of the molded body is reduced and evacuated. During installation the parts can be soldered in a known manner, Gluing and / or welding connected become. It is essential that this connection via remains gastight for a long period of time to ensure optimal thermal insulation.

The molded bodies are preferably attached by gluing from one side of the molded body  either with the inner wall of the outer container or with the outer wall of the inner container of the refrigerator, the gluing directly on the device wall can be done so that a composite in the arrangement Shaped body / adhesive / device wall.

However, it is also possible between the molded body and Device inner wall and / or outer wall spacer or insert spacers so that a composite in the arrangement of molded body / adhesive / spacer / Adhesive / device wall comes about. In this case a subsequent introduction of additional Spacers between the molded body and the inside wall of the device and / or outer wall in the already assembled, However, device not yet evacuated may be advantageous.

The moldings can in the area of the side walls Rear wall, the top and the bottom attached in the area of the door (s). limitations can differ from one another through constructive conditions of the cavity, such as refrigerant lines or electrical lines, screws, protruding Material parts and the like. To in these cases too an undisturbed attachment of the molded body as possible to arrive is the constructive elimination of the to strive for disruptive elements in the device cavity.

Evacuated plates can be used as suitable moldings according to German applications DE 38 28 669 A1, DE 40 29 405 A1 and DE 40 19 870 A1 (Degussa) can be used. Here are pressed filler plates, which in  evacuated a sheath of barrier film and were sealed. Preferred fillers can be Silicas and silicates can be used. Especially vacuum insulation panels can preferably be used with asymmetrical structure, which in DE 40 19 870 A1 are described, used. This Vacuum insulation panels have an internal pressure of 1 up to 4 mbar.

The moldings can have a symmetrical structure (DE 38 28 669 A1, DE 40 29 405 A1 or asymmetrical structure DE 40 19 870 A1.

Both sides are in the case of symmetrical shaped bodies trained and exist symmetrically to the center of the plate made of the same barrier film on both sides without aluminum layer.

The two exist in the case of asymmetrical moldings Pages made of different barrier films. The curved side consists of an aluminum-free Barrier film. The flat side can be made from one aluminum-containing barrier film, the one particularly high diffusion resistance Has water vapor and other gases.

Asymmetrical moldings are compared symmetrical moldings are preferably used.

Asymmetric moldings are preferred Form attached so that the flat, aluminum-containing  Side towards the device outer wall and the curved, aluminum-free side to the inside wall of the device comes to lie.

In this arrangement there is the aluminum one Side of the molded body on the warm side of the in Operation refrigeration device, and the aluminum-free, curved side on the cold side, with the following advantages:

The rates for water vapor and gas permeation from Aluminum-containing barrier films are among the Temperatures operating in the insulation of existing refrigeration devices occur, hardly measurable; your Temperature dependence is also extremely low. Therefore, the higher temperatures affect the warm side of the device hardly disadvantageous on the Water vapor and gas permeation into the molded body; the generally higher water vapor partial pressures affect the warm side of the device hardly compensate for the same reasons.

The rates for water vapor and gas permeation from aluminum-free barrier films are among the same conditions also very low; however is the temperature dependence of water vapor and Gas permeation from aluminum-free barrier films significantly more pronounced than aluminum-containing ones Barrier films; that's why they work lower temperatures on the cold side of the Device favorably on water vapor and gas permeation in the moldings. Another advantage is that  generally lower water vapor partial pressures on the cold side of the device.

The molded articles are preferred Design on the inside of the outside wall of the device attached.

The arrangement of several moldings on one Device wall can be done by the insulation boards in the Be bonded together. Here, the moldings be placed "at a distance" or "butt to butt".

Furthermore, it is possible not only to use the shaped bodies to be placed side by side, but also on top of each other.

Two or more moldings can be made before Attach in the refrigerator connected together with, for example, double-sided adhesive tape, with suitable plastic profiles or Plastic connectors.

As adhesives for attaching the moldings in Refrigerators can be used without glue set chemical reaction, like hot melt adhesives, Pressure sensitive adhesives or adhesive solutions.

Even adhesives that set through chemical reactions are suitable, such as curable phenoplasts and aminoplasts or reaction adhesives (polyester resins, epoxy resins, Polyurethane glue).  

Adhesives that do not have a chemical reaction are preferred set, such as hot melt adhesives or pressure sensitive adhesives.

Products that e.g. B. based thermoplastics, such as Vinyl copolymers, polyurethanes, polyesters or polyamides are used.

Products that, for example, can be used as pressure sensitive adhesives based on polyisoprene, polyisobutylene and Polyvinyl ether are made, find use.  

Products that are double-sided are preferred Represent adhesive tapes used.

It is also possible to remove unevenness in the molded body, like unintentional indentations, indentations, small Folding or the like by applying adhesive balance.

The adhesives can either on the molded body or on the device wall or simultaneously on both be applied. It is possible to apply of the adhesives, especially the double-sided ones Adhesive tapes, not just immediately before installing the Molded body to make in the refrigeration units, but already during the production of the molded body. Separate Shaped bodies can be placed in the Refrigerator with each other with double-sided adhesive tape get connected.  

After installing the panels in the isolation room of the The remaining insulation space (or Cavity) of the refrigerator is evacuated.

Evacuation can be carried out using known suction pumps a suction line, which is closed after evacuation will be done. When evacuating the cavities can an internal pressure of 5 to 900 mbar can be set.

In addition to evacuation, the cavities can also be used Additives such as glass fibers, coarse-grained powders or granules. These additives should have a coarse-grained or fibrous structure so that the evacuation is not hindered. The additives increase the insulation performance elevated. The additives can be such that during the evacuation the mechanical load can support the refrigerator wall.

The evacuation of the cavities according to the invention has the Advantage that the mechanical stability of the Refrigerator without the use of polyurethane foam given is. Furthermore, thermal bridges on the Places the refrigerator dismantled, at which one Shaped body not attached for geometric reasons can be.

Another advantage is that there is no insulating foam must be used. Questions like Environmental compatibility of the propellant gas and Recyclability of the foam material.

Claims (1)

Foam-free insulation for refrigeration devices, characterized in that evacuated molded bodies are attached to the outer container or inner container of the refrigeration device before the outer and inner containers are connected to one another, the outer and inner containers of the refrigeration device are then connected to one another in a gas-tight manner and the cavity which is formed is evacuated.