Insulation for baking ovens

Abstract

Baking oven insulation including at least a first insulating layer composed of a fiber material, and a metallic sheet material layer and a second insulating layer at least partially composed of a fiber material. The first and second insulating layers are located at opposite sides of the metallic sheet material layer. The first insulating layer is an inner layer to be arranged immediately at the outer side of a cavity wall of a baking oven and immediately at the inner side of the metallic sheet material layer. Moreover, the second insulating layer is an outer layer adapted to be spaced from the cavity wall of the baking oven. The first insulating layer has a thickness d1 which enables the first insulating layer to reduce the heat conduction from the cavity wall to the metallic sheet layer.

Claims

1. Baking oven insulation, comprising at least a first insulating layer composed of a fibre material, a metallic sheet material layer and a second insulating layer at least partially composed of a fibre material, wherein the first and second insulating layers are located at opposite sides of the metallic sheet material layer, wherein the first insulating layer is an inner layer to be arranged immediately at the outer side of a cavity wall of a baking oven and immediately at the inner side of the metallic sheet material layer and the second insulating layer is an outer layer adapted to be spaced from the cavity wall of the baking oven wherein the first insulating layer comprises a thickness d1 which enables the first insulating layer to reduce the heat conduction from the cavity wall to the metallic sheet layer, wherein the second insulating layer comprises a thickness d2, wherein the ratio d1/d2 is in the range between 0.25 and 0.75.

2. Baking oven insulation, comprising at least a first insulating layer composed of a fibre material, a metallic sheet material layer and a second insulating layer at least partially composed of a fibre material, wherein the first and second insulating layers are located at opposite sides of the metallic sheet material layer, wherein the first insulating layer is an inner layer to be arranged immediately at the outer side of a cavity wall of a baking oven and the second insulating layer is an outer layer adapted to be spaced from the cavity wall of the baking oven and wherein the fibre material of the first insulating layer is made of glass wool with a material density between 20-50 kg/m.sup.3, or rock wool with a material density between 40-60 kg/m.sup.3.

3. Baking oven insulation according to claim 1, wherein the second insulating layer is formed by a stack of insulating sub-layers comprising at least two sub-layers.

4. Baking oven insulation according to claim 1, wherein the fibre material of the first insulating layer is made of glass wool with a material density between 20-50 kg/m.sup.3, or rock wool with a material density between 40-60 kg/m.sup.3.

5. Baking oven insulation according to claim 1, wherein the metallic sheet material layer is formed by a metallic foil.

6. Baking oven insulation according to claim 1, wherein the first and second insulating layers immediately lie against the metallic sheet material layer.

7. Baking oven insulation according to claim 1, wherein the second insulating layer comprises a thickness d2, wherein the ratio d1/d2 is in the range between 0.25 and 0.75.

8. Baking oven insulation according to claim 1, wherein d1 is in the range of 0.5 cm to 1.5 cm and/or the second insulating layer comprises a thickness d2 in the range of 1 cm to 2.5 cm.

9. Baking oven insulation according to claim 1, wherein the second insulating layer comprises a fibre material with higher material density than the first insulating layer.

10. Baking oven insulation according to claim 1, wherein the fibre material of the first and second insulating layer comprises a coefficient of thermal conductivity in the range of 0.030-0.045 W/mK and/or a specific heat capacity in the range of 840-1000 J/kgK.

11. Baking oven insulation according to claim 1, wherein the second insulating layer comprises a fibre material with higher heat capacity than the first insulating layer.

12. Baking oven insulation according to claim 1, wherein the first and second insulating layers are arranged in parallel or substantially in parallel to one another.

13. Baking oven insulation according to claim 3, wherein the insulating sub-layers are woven together in order to build an integrally formed layer.

14. Baking oven insulation according to claim 3, wherein the material density of a second insulating sub-layer being spaced from the metallic sheet material layer by means of the first insulating sub-layer is at least 10% higher than the material density of the first insulating sub-layer.

15. Baking oven insulation according to claim 1, wherein the second insulating layer is formed by a stack of insulating sub-layers comprising at least three sub-layers.

16. Baking oven insulation according to claim 15, wherein a first sub-layer arranged in direct proximity to the metallic sheet material layer and a third sub-layer being spaced from the first sub-layer by a second sub-layer are composed of a fibre material.

17. Baking oven insulation according to claim 15, wherein a second sub-layer arranged between a first sub-layer and a third sub-layer is formed by a rigid insulation material.

18. Baking oven comprising an oven cavity with a cavity wall, characterized in that, the cavity wall is at least partially covered by a baking oven insulation according to claim 1.

19. Baking oven insulation according to claim 5, said metallic foil being an aluminium foil.

20. Baking oven insulation according to claim 17, said rigid insulation material comprising micro-porous silica or foam glass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawing, in which:

(2) FIG. 1 shows a schematic diagram of a baking oven according to the invention;

(3) FIG. 2 shows a schematic diagram of a baking oven insulation according to a first embodiment of the invention;

(4) FIG. 3 shows a schematic diagram of a baking oven insulation according to a second embodiment of the invention; and

(5) FIG. 4 shows a schematic diagram of a baking oven insulation according to a third embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) The present invention will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Throughout the following description similar reference numerals have been used to denote similar elements, parts, items or features, when applicable.

(7) FIG. 1 illustrates a baking oven 10. The baking oven 10 comprises an oven cavity 11 which is adapted to receive the food to be cooked and/or baked. The baking oven 10 may comprise at least one heating element for heating the interior of the oven cavity 11. Thereby, the temperature inside the oven cavity 11 is raised to a temperature significantly higher than the ambient temperature of the baking oven 10.

(8) In order to keep thermal losses as low as possible and to protect the surrounding area of the baking oven, particularly when the oven is integrated in a furniture niche or cabinet, the cavity 11 of the baking oven 10 is encapsulated by a thermal baking oven insulation 1.

(9) FIG. 2 shows a first embodiment of a baking oven insulation 1. The baking oven insulation 1 may be arranged in close proximity to the outer side of a cavity wall 12 confining the oven cavity 11. Preferably, the baking oven insulation 1 may be arranged immediately at the outer side of the cavity wall 12. Furthermore, the baking oven insulation 1 may be arranged between the cavity wall 12 and a housing 13, which builds the chassis of the baking oven 10.

(10) The baking oven insulation 1 may be a flexible insulation constituted by a stack of multiple layers, wherein adjacent layers abut against each other without any gaps or spacings between said layers. Specifically, the baking oven insulation 1 comprises a first insulating layer 2 which immediately adjoins to a metallic sheet material layer 3. The metallic sheet material layer 3 adjoins at the side opposite to the first insulating layer 2 to a second insulating layer 4. Preferably, the metallic sheet material layer 3 adjoins immediately at the side opposite to the first insulating layer 2 to a second insulating layer 4. The first insulating layer 2 forms an inner layer immediately adjacent to the outer side of the cavity wall 12 of the oven cavity 11 effecting a spacing between the cavity wall 12 and the metallic sheet material layer 3.

(11) The metallic sheet material layer 3 acts as an efficient reflector for heat radiation escaping from the oven cavity 11 through the cavity wall 12. In other words, the metallic sheet material layer 3 forms a reflective barrier for heat radiation exhausting through the cavity wall 12. The metallic sheet material layer 3 may be formed by a metallic foil, e.g. an aluminium foil. The second insulating layer 4 forms an outer insulating layer which may be located adjacent to the housing 13 of the baking oven 10. For example, the first and second insulating layers 2, 4 may be adhered immediately to the metallic sheet material layer 3.

(12) The first and second insulating layers 2, 4 may be formed by a fibre material, specifically by a mineral fibre material. Preferably, the fibre material is glass wool or stone wool. Furthermore, the fibre material of the first and second insulating layers 2, 4 may comprise a coefficient of thermal conductivity in the range of 0.030-0.045 W/mK. The specific heat capacity of the fibre material of the first and second insulating layers 2, 4 may be in the range of 840-1000 J/kgK. The density of the fibre material may be in the range of 20-200 kg/m.sup.3, preferably in the range of 20-50 kg/m.sup.3, most preferably around 35 kg/m.sup.3 for glass wool and in the range of 40-60 kg/m.sup.3, preferably around 45 kg/m.sup.3 for stone wool. By using a fiber material with upper mentioned parameters, a high thermal insulation of the oven cavity 11 may be achieved, wherein the baking oven insulation 1 comprises a low specific heat capacity and/or mass. Thereby, the storage of heat within the baking oven insulation 1 is minimized resulting in a minimal energy loss due to heating up and cooling down the baking oven insulation 1.

(13) The first and second insulating layers 2, 4 may be formed by the same fiber material or different fiber materials. Preferably, the specific heat capacity of the fiber material of the second insulating layer 4 may be higher than the specific heat capacity of the fiber material of the first insulating layer 2. Thereby, the energy losses after heating up the oven cavity (phase of constant or essentially constant temperature within the oven cavity) are reduced. According to another embodiment, the first insulating layer 2 as an inner layer may be constituted by stone wool and the second insulating layer 4 forming the outer layer may be constituted by glass wool, because stone wool has higher temperature stability than glass wool.

(14) The first insulating layer 2 comprises a first thickness d.sub.1 and the second insulating layer 4 comprises a second thickness d.sub.2. The first thickness d.sub.1 may be the same or different to the second thickness d.sub.2. According to an aspect of the invention, the first thickness d.sub.1 may be smaller than the second thickness d.sub.2 (d.sub.1<d.sub.2). The ratio between the first and second thicknesses d.sub.1, d.sub.2 may be in the range between 0.25 and 3, preferably between 0.25 and 1, most preferably between 0.25 and 0.5. The first thickness d.sub.1 may be between 5 mm and 20 mm, preferably between 8 mm and 12 mm, specifically 10 mm.

(15) According to a different configuration, the density of the material of the first and/or second isolating layer 2, 4 may be inhomogeneous. FIG. 3 shows a further embodiment of a baking oven insulation 1.

(16) The basic structure of the baking oven insulation 1 is similar to the embodiment of FIG. 2, so, in the following only the differences to the embodiment of FIG. 2 are explained in detail. Apart from that, the description of the embodiment of FIG. 2 may also apply to the embodiment of FIG. 3. The main difference of the baking oven insulation of FIG. 3 is that the second isolating layer 4 comprises two sub-layers 4.1, 4.2, i.e. is formed by a first sub-layer 4.1 and a second sub-layer 4.2. The first sub-layer 4.1 may be immediately adjacent to the metallic sheet material layer 3 and the second sub-layer 4.2 abuts against the first sub-layer 4.1. Said first and second sub-layers 4.1, 4.2 may be interconnected such that the second sub-layer 4.2 is adhered to the first sub-layer 4.1. Said adhesion may be caused by the wadding-like or cotton-like structure of the fibre material of the first and second sub-layers 4.1, 4.2. In order to enhance the interconnection of the first and second sub-layer 4.1, 4.2, said layers may be woven together. Also other additional adhesion-enhancing methods or means, e.g. needling, may be possible.

(17) The first and second sub-layer 4.1, 4.2 may be arranged such that said sub-layers are in parallel or substantially in parallel to one another. In addition, the first and second sub-layer 4.1, 4.2 may comprise the same material or different material. According to one embodiment, the first sub-layer 4.1 may comprise a lower material density than the second sub-layer 4.2. According to another embodiment, the first sub-layer 4.1 may comprise a higher material density than the second sub-layer 4.2. For example, the material densities may differ by at least 10%, preferably by 15%. The thickness of the second insulating layer 4 (sum of the thicknesses of the first and second sub-layer 4.1, 4.2) may be in the range of 1 cm to 2.5 cm, preferably 1.3 cm to 1.8 cm.

(18) FIG. 4 shows a third embodiment, in which the second isolating layer 4 is constituted by an inhomogeneous material. Specifically, the second isolating layer 4 is formed by a stack of sub-layers 4.1, 4.2, 4.3, namely a first sub-layer 4.1, a second sub-layer 4.2 and a third sub-layer 4.3. The first isolating layer 2 and the metallic sheet material layer 3 are configured according to the features described above. Specifically, the first and third sub-layers 4.1, 4.3 may be formed by a fibre material. The fibre material may be composed as described above. The second sub-layer 4.2 may be embedded within the first and third sub-layers 4.1, 4.3, wherein the first sub-layer 4.1 adjoins to the metallic sheet material layer 3 and the third sub-layer 4.3 forms the outer layer located in proximity to the housing 13.

(19) The second sub-layer 4.2 may be formed by a highly insulating rigid or semi-rigid insulation material, e.g. micro-porous silica or foam glass. Thereby, the heat insulation effected by the baking oven insulation 1 is optimized.

(20) Preferably, the sum of the thicknesses of the first, second and third sub-layer 4.1, 4.2, 4.3 is d.sub.2 and the thickness of the first insulating layer 2 is d.sub.1, wherein the first thickness d.sub.1 may be smaller than the second thickness d.sub.2 (d.sub.1<d.sub.2). The ratio between the first and second thicknesses d.sub.1, d.sub.2 may be in the range between 0.25 and 3, preferably between 0.25 and 1, most preferably between 0.25 and 0.5. The first thickness d.sub.1 may be between 5 mm and 15 mm and the thickness d.sub.2 may be in the range of 1 cm to 2.5 cm, preferably 1.3-1.8 cm.

(21) The baking oven insulation 1 as described above is advantageous because the heat losses are reduced in comparison to prior art insulations. By using at least two insulating layers consisting of fibre material which are encapsulating a metallic sheet material layer, the baking oven insulation 1 is adapted to encapsulate the oven cavity without any spacings between the cavity wall and the baking oven insulation 1 thereby reducing convective heat flow between the cavity wall and the baking oven insulation 1. Due to the higher insulating effect the baking oven insulation 1 is very suitable if space restrictions prohibit the usage of insulation with high thickness. By using fibre material, the mass, respectively, the heat capacity of the baking oven insulation 1 is reduced. Thus, the energy loss due to heating up and cooling down the baking oven insulation 1 is reduced. In addition, at least the outer layers of the baking oven insulation 1 are flexible thereby enabling an optimal adaption to the cavity wall, respectively, the housing compared to rigid insulation materials.

(22) Above, embodiments of the baking oven insulation according to the present invention as defined in the appended claims have been described. These should be seen as merely non-limiting examples. As understood by a skilled person, many modifications and alternative embodiments are possible within the scope of the invention.

LIST OF REFERENCE NUMERALS

(23) 1 baking oven insulation 2 first insulating layer 3 metallic sheet material layer 3 second insulating layer 4.1 first sub-layer 4.2 second sub-layer 4.3 third sub-layer 10 baking oven 11 oven cavity 12 cavity wall 13 housing d.sub.1 thickness of first insulating layer d.sub.2 thickness of second insulating layer