Thermal insulation element

Abstract

Thermal insulation element (1) comprising a plate-like base body (2) with a first planar side and a second planar side, and a vacuum insulation (3), in particular a film-wrapped vacuum insulation, which is arranged between the first planar side and the second planar side, wherein the first planar side and the second planar side are formed by a respective cover layer (4, 5), and on at least one of the two planar sides the respective cover layer (4) is only partially connected, in particular bonded or welded, to the vacuum insulation (3), characterized in that the cover layer (4) which is only partially connected has a relief structure (6) in all, a plurality of or a multiplicity of regions which are not connected to the vacuum insulation (3), the relief structure being designed for compensating thermal expansion or thermal contraction.

Description

TECHNICAL FIELD

[0001] The present application relates to a thermal insulation element for thermal insulation. Such thermal insulation elements are used, inter alia, in refrigeration devices or incubators, for example in refrigeration and / or freezing devices. It is of great importance in these devices that the insulation from the interior container to the outside is of as high a quality as possible, whereby the energy required for refrigeration or warming can be kept as low as possible. BACKGROUND

[0002] Thermal insulation elements are usually used as sandwich elements composed of an insulating material and an outer cover layer. This is known, inter alia, from insulating elements based on polyurethane foam, wherein the foam assumes the insulating function and also a good adhesion to the cover layer, which in turn also enables a high mechanical stability.

[0003] Steel, aluminum or plastic is usually used as a cover layer. In order to avoid thermal bridges, it is advantageous for the cover layer to be composed of plastic at least in the edge region of the sandwich element. In cost-efficient constructions, such as, for example, in domestic refrigeration devices, the entire interior space is usually configured with a plastic cover layer.

[0004] It is problematic here that the thermal expansion coefficient of plastic is usually significantly higher than that of steel. Thus, the expansion coefficient of polystyrene is approximately 7*10 -5 [1 / K] and the expansion coefficient of steel is 1.2*10 -5 [1 / K]. In the case of a temperature difference of approximately 43 K in a freezer cabinet, a thermal contraction of 0.3% is obtained for polystyrene, i.e. in a large device of 2 m height, the length of the interior container contracts by 6 mm. The contraction is prevented by the housing, whereby, however, stresses in the thermal insulation element are obtained, which must be prevented in terms of construction.

[0005] In the case of planar elements, the stresses are at least partially reduced by a bending of the element. The phenomenon is known, inter alia, in the doors of domestic refrigeration devices. If a freezer cabinet door having a height of 170 cm and a thickness of 50 mm is constructed only by a thermal insulation element in sandwich construction, wherein the cover layer on one side is composed of a flat metal plate and the cover layer on the other side is composed of a flat plastic plate, then the door on the cold side is bent in the middle by approximately 22 mm. The process is illustrated in Figure 1 .

[0006] In fact, the bending is reduced by the stiffness of the door panel. However, the metal plate stiffness cannot be arbitrarily increased, because the height of the lateral metal plate edge, which is the main influence on the metal plate stiffness, is limited for constructional reasons, and the metal plate thickness cannot be arbitrarily increased for cost reasons. For this reason, it is known from the prior art to additionally work with unloading grooves on the plastic side. Another possibility known from the prior art for reducing the door bending consists in applying metal strips on the plastic side, which reduce the shrinkage of the plastic, and thus the door bending, due to the smaller thermal expansion. However, disadvantageous here is the increased production effort and the additional material input for the metal strips.

[0007] Problem areas for conventional refrigeration appliance doors are known, which have a PU foam as insulating material. Figure 2 shows different aspects and solutions of the problem in the prior art. However, the PU foam as insulating material is limited in its possibilities with regard to the insulating effect and is increasingly supplemented or replaced by vacuum insulation or film-wrapped vacuum insulation.

[0008] Vacuum insulation with a high-barrier film as gas-impermeable outer shell is prior art and is increasingly popular in the implementation of thermal insulation elements. The use of a barrier film can achieve sufficient tightness with respect to gas particles diffusing inward, without causing excessive thermal bridges in the outer shell or being susceptible to thermal or mechanical stresses.

[0009] However, the film is sensitive to mechanical damage and must be protected in use. Furthermore, the vacuum insulation in the sandwich composite can absorb mechanical forces very well, since the stiffness of the loaded insulation is generally similar or greater than that of conventional insulating materials, in particular plastic foams. SUMMARY

[0010] It is an object of the present invention to reduce or overcome the above-mentioned problem of the subject matter, i.e. the bending of the thermal insulation element caused by thermal differences. This is achieved by means of a thermal insulation element according to the invention.

[0011] According to the invention, the thermal insulation element comprises a plate-like base body having a first planar side and a second planar side, and a vacuum insulation, which is arranged between the first planar side and the second planar side, wherein the first planar side and the second planar side are formed by a respective cover layer, and on at least one of the two planar sides the respective cover layer is only partially connected, in particular bonded or welded, with the vacuum insulation. The invention is characterized in that the cover layer which is only partially connected has an unloading structure in all, multiple or a plurality of regions which are not connected with the vacuum insulation, which is designed to compensate for thermal expansion or thermal shrinkage.

[0012] Because the cover layer is not entirely connected or bonded to the vacuum insulator, it can prevent bending caused by temperature differences between the two cover layers in areas not bonded to the vacuum insulator. This is achieved by thermal contraction or expansion through the expansion or contraction of the unloading structure not connected or bonded to the vacuum insulator. Therefore, it is feasible that the thermal expansion or contraction of the cover layer is reduced by altering the unloading structure without significant bending of the vacuum insulator or insulation element.

[0013] The vacuum insulator here can be a membrane-encapsulated vacuum insulator, which, for example, has pearlite as the core material.

[0014] Vacuum insulators with pearlite as the core material exhibit better performance than PU foam (approximately 7*10) in the insulation layer. -5 [1 / K]) Smaller thermal expansion (<1*10) -5 [1 / K]). However, the advantage of lower thermal expansion is not only evident in the case of pearlite as a filler material, but also applies to all film-wrapped vacuum insulators, because unlike foamed insulators, film-wrapped vacuum insulators do not self-adhere to the cover layer. Therefore, it is also advantageous to add here that the sandwich structure in the insulator element having a film-wrapped vacuum insulator can be produced by a manufacturing process in which the bonding of the portion between the cover layer and the vacuum insulator can be achieved without problems.

[0015] An advantageous modification according to the invention is proposed herein, wherein the membrane-wrapped vacuum insulator is sandwiched between the first and second covering layers, preferably wherein the membrane-wrapped vacuum insulator is directly connected to the two covering layers.

[0016] According to another alternative modification of the invention, the covering layer may be composed of plastic, steel and / or aluminum, or one of these materials.

[0017] Typically, the insulation element is constructed with a covering layer made of different materials. Refrigerated cabinet doors, due to stability requirements and an improved visual appearance, usually have a steel exterior, while the interior is made of plastic. Therefore, in such doors, the insulation element is constructed with an inner covering layer made of plastic and an outer covering layer made of steel.

[0018] According to another improvement of the invention, the covering layer and the vacuum insulation are partially connected to each other via a plurality of connection regions spaced apart from each other.

[0019] Between the connection regions, respectively, a relief structure is provided, which is formed by the region of the cover layer which is not connected to the vacuum insulation. By means of the connection or adhesion of only the part of the cover layer to the vacuum insulation, the unconnected section of the cover layer can absorb and transfer thermal expansion or contraction, so that the forces which cause the bending are reduced, which are exerted by the cover layer onto the vacuum insulation.

[0020] It can be advantageously proposed here that the distance between the connection regions is less than 100 mm, preferably less than 75 mm and preferably less than 50 mm.

[0021] The provision of a plurality of connection regions which are spaced apart from one another by less than 100 mm contributes to the stability of the cover layer and ensures that no negative impression is produced even when the cover layer is examined haptically.

[0022] Furthermore, it can be proposed according to the application that all, a plurality or a multiplicity of the connection regions are strip-like and preferably extend parallel to one another at the cover layer.

[0023] By the strip-like provision of the connection regions, a reliable connection between the cover layer and the vacuum insulation is produced, which can be achieved simply and industrially. If the connection regions are furthermore also oriented parallel to one another, this shows a further simplification when manufacturing the thermal insulation element according to the application, since a plurality of parallel connection strips can be created or applied in a unique mechanical or manual work step. Furthermore, by the parallel orientation of the connection strips and thus also the parallel provision of the relief structures which are provided between the connection strips, an advantageous visual design of the cover layer results.

[0024] A further advantageous variant according to the application can be proposed that the connection regions are provided between the cover layer and the vacuum insulation in a regular structure, wherein preferably the distance between the connection regions provided between the cover layer and the vacuum insulation is identical.

[0025] The regular provision of the connection regions between the cover layer and the vacuum insulation ensures that the same stability and a particularly advantageous visual impression is maintained over the entire area of the cover layer.

[0026] Preferably, it is proposed according to the application that the relief structure is convexly shaped with respect to the vacuum insulation and preferably is clock-shaped or bell-shaped in a sectional view.

[0027] By the convex design of the relief structure with respect to the vacuum insulation, the relief structure can compensate thermal expansion or thermal contraction without an excess of force being introduced into the vacuum insulation which is connected to the cover layer here. This is achieved in that the convex relief structure protrudes or is lowered with respect to the essentially flat formed surface of the vacuum insulation, i.e. expands or contracts.

[0028] It can also be proposed here that the maximum spacing from the inner side of the unloading structure protruding from the vacuum insulation is less than five times the thickness of the cover layer, preferably less than three times the thickness of the cover layer. It can be proposed here that the spacing from the vacuum insulation to the inner side of the cover layer is at least one thickness of the cover layer.

[0029] According to a further advantageous design of the application it can be proposed that a gap, in particular an air gap, is provided between the unloading structure and the vacuum insulation.

[0030] The gap which allows the fluid to enter and exit upon thermal expansion or thermal contraction enables a movement of the cover layer or the unloading structure towards or away from the vacuum insulation.

[0031] Furthermore, according to the application it can be proposed that the area share of the unconnected region between the cover layer and the vacuum insulation is greater than the area share of the connected region between the cover layer and the vacuum insulation, preferably more than twice the area share of the connected region.

[0032] The application also comprises a door of a refrigeration and / or freezing appliance, wherein the door or the flap comprises or consists of a thermal insulation element according to one of the variants discussed above.

[0033] It can be proposed here that the connected region extends strip-like transversely to the longitudinal direction of the door and preferably over the entire width of the door. Thereby, in particular a problematic bending of the door in the longitudinal direction is prevented, since a thermal contraction occurring for example on the cover layer formed towards the inside of the refrigeration cabinet is absorbed by the at least one unloading structure.

[0034] According to a further alternative refinement it can be proposed here that the unloading structure provided with the thermal insulation element is provided on the side of the door facing the interior of the refrigeration and / or freezing appliance. There, the unloading structure can be the surface of the door.

[0035] It can also be proposed, preferably, that the cover layer not provided with the unloading structure is provided with the thermal insulation element at the outer side of the door facing the exterior of the refrigeration and / or freezing appliance, the cover layer preferably being made of aluminum or steel.

[0036] The provision of an outer contour of the door made of steel or aluminum ensures a high-quality visual impression and also contributes to the outer side being insensitive to impacts or other environmental influences.

[0037] It is to be noted here that the expressions "one" and "a" do not necessarily mean just one element, although this is one possible embodiment, but can also mean a plurality of elements. Likewise, the use of the plural also includes the presence of a single relevant element, and vice versa. BRIEF DESCRIPTION OF DRAWINGS

[0038] Further advantages, features and details of the invention become clear from the description according to the drawings. Shown here is:

[0039] Figure 1 A diagram is shown for illustrating the bending of a thermal insulation element with two cover layers and an insulation arranged therebetween;

[0040] Figure 2a - b shows a side view of a thermal insulation element according to the prior art in a state of unloaded and due to thermal contraction induced bending;

[0041] Figure 3a - b shows a side view of another thermal insulation element according to the prior art in a state of unloaded and due to thermal contraction induced bending;

[0042] Figure 4 A sectional view of a plug holder in a fixed state at a refrigeration and / or freezing appliance is shown; and

[0043] Figure 5 An enlarged partial sectional view of a vacuum insulation is shown. DETAILED DESCRIPTION

[0044] Figure 1 An insulation 1 of sandwich construction is shown, the outer cover layers of which are metal sheets or plastic. Here, the outer side is arranged to the left in the drawing, so that the cover layer consisting of metal sheets is arranged on the outside and the cover layer consisting of plastic is arranged on the inside. If such an insulation is now cooled down again on the inside, while the outside is kept at a constant temperature level, a bending as shown occurs.

[0045] Figure 2a and Figure 2b A side view of a conventional insulation is shown, wherein the inside arranged in the upper part of the diagram is subjected to the same temperature level as the outside arranged in the lower part of the diagram in the diagram and in the other case to a significantly lower temperature level, so that a bending occurs (as in Figure 2b ).

[0046] It is already known from the prior art that grooves 11 are provided which extend transversely to the longitudinal direction of the element in order to reduce the bending. In Figure 3a and 3b such a thermal insulation element 1 with transversely extending grooves 11 is shown, according to which it can be seen that the bending is less than in Figure 2b . The grooves 11 here ensure an increased stability at the cover layer of the thermal insulation element 1 facing the inside, so that the thermal contraction does not affect so strongly.

[0047] Figure 4A sectional view of a thermal insulation element 1 according to the application is shown. It can be seen that a thermal insulation body 3 is arranged between two cover layers 4, 5, which can be a film- wrapped vacuum insulation body 3. Preferably, it can also be proposed here to use spherulites as core material, since these have proven to be particularly advantageous for forming a film- wrapped vacuum insulation body.

[0048] Here, the cover layer 4 is typically oriented towards a colder space than the cover layer 5. It can be seen that the cover layer 4 is not connected or bonded to the vacuum insulation body 3 over the entire area, but rather is characterized by regularly having unconnected areas. These areas are unloading structures 6, which are designed to absorb thermal expansion or thermal contraction. The connection areas 7, in which the cover layer 4 is connected or bonded to the vacuum insulation body 3, extend here strip-like and equidistantly over the planar side of the vacuum insulation body 3.

[0049] Starting from the connection areas 7, the unloading structures 6 are structures composed of two legs in the sectional view, wherein each leg is approximately equally long and the legs together enclose an obtuse angle.

[0050] The regularity of the connection areas 7 or the unloading structures 6 arranged therebetween produces an advantageous visual impression of the cover layer 4.

[0051] Figure 5 An enlarged partial sectional view of the vacuum insulation body 1 is shown, so that the area between two adjacent connection areas 7 and the unloading structure 6 arranged therebetween can be seen. Here, the unloading structure 6 in the state of thermal contraction is shown by means of a solid line, while the stress-free state of the unloading structure 6 or the corresponding cover layer 4 is shown by means of a dotted line. It can be seen that in the cooled state of the cover layer 4, the unloading structure 6 is contracted, which is shown in the reduction of the spacing of the inner side of the unloading structure 6 from the vacuum insulation body 3. By thermal contraction, the cap-shaped or bell-shaped profile of the unloading structure 6 is brought closer to the facing surface of the vacuum insulation body 3.

[0052] It is advantageous here that length changes caused by temperature changes and not occurring on the other side of the vacuum insulation body 3 can be compensated without a bending of the vacuum insulation body 3 occurring. The non-areal connection or non-areal bonding of the cover layer 4 allows a thermal contraction in the unloading structure 6 so that forces which would otherwise normally be induced into the vacuum insulation body 3 do not occur.

Claims

1. A thermal insulation element (1), comprising: a plate-like base body (2) having a first planar side and a second planar side, and a vacuum insulation (3) arranged between the first planar side and the second planar side, wherein the first planar side and the second planar side are constituted by a respective cover layer (4, 5), and at at least one of the two planar sides, the respective cover layer (4) is only partially connected with the vacuum insulation (3), characterized in that the partially connected cover layer (4) has a relief structure (6) in all, a plurality of, or a large part of the areas not connected with the vacuum insulation (3), the relief structure being designed for compensating thermal expansion or thermal contraction.

2. The thermal insulation element (1) according to claim 1, wherein the vacuum insulation (3) is a film-wrapped vacuum insulation.

3. The thermal insulation element (1) according to claim 1, wherein at at least one of the two planar sides, the respective cover layer (4) is only partially bonded or welded with the vacuum insulation (3).

4. The thermal insulation element (1) according to any one of claims 1 to 3, wherein the vacuum insulation (3) is sandwiched between a first cover layer (4) and a second cover layer (5).

5. The thermal insulation element (1) according to claim 4, wherein the vacuum insulation (3) is directly connected with both cover layers (4, 5).

6. The thermal insulation element (1) according to any one of claims 1 to 3, wherein the cover layer (4) comprises or consists of plastic, steel and / or aluminum, or one of these materials or a combination of these materials.

7. The thermal insulation element (1) according to any one of claims 1 to 3, wherein the cover layer (4) and the vacuum insulation (3) are partially connected with each other via a plurality of connection areas (7), the connection areas being spaced apart from each other.

8. The thermal insulation element (1) according to claim 7, wherein the spacing of the connection areas (7) is less than 100 mm.

9. The thermal insulation element (1) according to claim 8, wherein the spacing of the connection areas (7) is less than 75 mm.

10. The thermal insulation element (1) according to claim 8, wherein the spacing of the connection areas (7) is less than 50 mm.

11. The thermal insulation element (1) according to claim 7, wherein all, a plurality of, or a multiplicity of the connection areas (7) are constituted strip-like at the cover layer (4).

12. The thermal insulation element (1) according to claim 11, wherein all, a plurality of, or a multiplicity of the connection areas (7) extend parallel to each other.

13. The thermal insulation element (1) according to claim 7, wherein the connection areas (7) are arranged between the cover layer (4) and the vacuum insulation (3) in a regular structure.

14. The thermal insulation element (1) according to claim 13, wherein the spacing between the connection areas (7) arranged between the cover layer (4) and the vacuum insulation (3) is identical.

15. The thermal insulation element (1) according to any one of claims 1 to 3, wherein the unloading structure (6) is convexly shaped with respect to the vacuum insulation (3).

16. The thermal insulation element (1) according to claim 15, wherein the unloading structure (6) is bell-shaped or hood-shaped in a cross-sectional view.

17. The thermal insulation element (1) according to claim 15, wherein the maximum distance from the inner side of the unloading structure (6) protruding from the vacuum insulation (3) is less than five times the thickness of the cover layer (4).

18. The thermal insulation element (1) according to claim 17, wherein the maximum distance is less than three times the thickness of the cover layer (4).

19. The thermal insulation element (1) according to any one of claims 1 to 3, wherein a gap is provided between the unloading structure (6) and the vacuum insulation (3).

20. The thermal insulation element (1) according to claim 19, wherein an air gap is provided between the unloading structure (6) and the vacuum insulation (3).

21. The thermal insulation element (1) according to any one of claims 1 to 3, wherein the area share of the unconnected area between cover layer (4) and vacuum insulation (3) is greater than the area share of the connected area between cover layer (4) and vacuum insulation (3).

22. The thermal insulation element (1) according to claim 21, wherein the area share of the unconnected area between cover layer (4) and vacuum insulation (3) is greater than twice the area share of the connected area.

23. A door of a refrigeration and / or freezing appliance, wherein the door or shutter comprises or consists of a thermal insulation element (1) according to any one of claims 1 to 22.

24. The door according to claim 23, wherein the connected areas (7) stretch strip-like transversely to the longitudinal direction of the door.

25. The door according to claim 24, wherein the connected areas (7) extend over the entire width of the door.

26. The door according to any one of claims 23 to 25, wherein the unloading structure (6) of the thermal insulation element (1) is provided on the side of the door facing the interior of the refrigeration and / or freezing appliance.

27. The door according to any one of claims 23 to 25, wherein the cover layer (5) of the thermal insulation element (1) without unloading structure (6) is provided on the outer side of the door facing the exterior of the refrigeration and / or freezing appliance.

28. The door according to claim 27, wherein the cover layer is made of aluminum or steel.

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