EP0690268B1 - Heating household appliance - Google Patents

Abstract

The thermal insulation is used for enclosing the sides of the oven space and provided by several relatively spaced foil layers, joined together at defined points to form a cellular structure, with a number of air-filled pockets. At least one of the foil layers is provided with an air-tight sealed edge on all sides, acting as a flexible fixing and/or coupling element. Pref. the layers are provided by A1 foils, each layer comprising at least three foils, two of which act as cover layers (a,d) on either side of at least one central spacer foil (b,c) with a meandering configuration. <IMAGE>

Description

The invention relates to a heating appliance according to the Preamble of claim 1.

Thermal insulation of ovens are used in practice currently only fiber insulating materials such as Ceramic barrel mats, used with which the oven muffle with Inclusion of any external heating elements is surrounded. Such fibrous insulating materials are increasingly considered viewed as hazardous to health. According to a known proposal (DE-A 25 49 834) is used instead of fibrous insulating material an insulating film, e.g. made of aluminum, in one or several layers around the wall surfaces of the furnace muffle wrapped, air chambers by means of spacer strips on the edge between the wall surfaces of the oven muffle and the Insulating film, or between the individual layers of the insulating film, be created. The spacer strips must be used here again made of a material that can withstand higher temperatures, as in normal roasting and baking processes or in Extreme case when performing pyrolytic self-cleaning processes inside the oven muffle and accordingly reduces also occur on the outside of the oven muffle withstands. With the mentioned proposal it is recommended to do so To use asbestos foam, which is highly heat-resistant, however again is not without problems.

The invention has for its object a domestic heating appliance, esp. cooking device, e.g. an oven, in relation to design the thermal insulation so that health Problems no longer occur and the insulation in addition to good workability and small space requirements the highest degree of, also partially variable, thermal insulation owns.

This object is achieved according to the invention by the Labeling part of claim 1 measures listed. Embodiments of the invention according to the invention result itself from the following claims.

Tests have shown that at least largely airtight Completion of those enclosed in the film layer A targeted and increased insulation effect can be achieved in air chambers is by replacing the air chambers heated air partially limited or larger Areas can be prevented. By forming Fastening and / or connecting elements through the film edges or edge sections of the foils themselves at these points a very small material cross section and excellent manageability and adaptability of these e.g. edge-side fastening and / or connecting elements to the respective placement of the film layer or layers in the vicinity of e.g. through an oven door or another housing of limited equipment space. Through training these fastening and / or connecting elements e.g. the ability to seal multiple layers of film to be arranged close together and e.g. the compacted and bendable Bend the edges accordingly or closed edge sections a larger film layer as a corner connector between film layers arranged at an angle to one another to use. By appropriate surface profiling the top layers of the film layers or the edges or edge sections can easily conduct heat from housing or furnace muffle to the film layer or between the fastening and / or connecting elements specifically reduced be, so that, for example, only point contact of the aforementioned parts take place. Not least the advantage of the invention is that the invention Products 100% pure and recyclable could be.

According to a preferred embodiment, spacer elements to form the air chambers through the foils themselves formed by e.g. cup-shaped embossing points possess that support each other on a small surface. There may be some contact between the Films also within the outer edges or edge sections be desired in order to target out extremely high thermal loads Places, e.g. the oven muffle, heat energy in less to be able to derive highly contaminated places. It can also be be desired, e.g. the edge-side fastening and / or To use connecting elements to a so-called Heat dissipation e.g. from the front device area such as from the area of the muffle flange on the front. A preferred measure for mounting and positioning the individual foils are spaced apart by profiling the e.g. internal foils e.g. such that the film layer is honeycomb-shaped in cross section is formed, it can be provided that the mutually supportive embossments represent a mutual one Establish the individual foils in the composite, so that e.g. different thermal expansions or mechanical Loads are absorbed.

The invention is illustrated in the drawing Embodiments explained below.

Fig. 1

die perspektivische Darstellung eines Wärme-Hausgerätes in Form einer Backofenmuffel,

Fig. 2 und 3

zwei unterschiedliche Belegungsvarianten einer Backofenmuffel mit Folienschichten in schematischer Darstellung,

Fig. 4

eine Backofenmuffel mit aus mehreren zusammenhängenden Folienschichten gebildeter, abgewickelter Isolierung,

Fig. 5 bis 7

eine vereinfachte Darstellung des Randbereiches einer bzw. zweier Folienschichten sowie die Ausgestaltung des Randes bzw. Randabschnittes.

Fig. 8

eine Draufsicht auf einen Folienschichtrand bzw. Randabschnitt,

Fig. 9

die Draufsicht auf eine Backofenmuffel mit diese umhüllender, als Folienschicht ausgebildeter Isolierung in Schnittdarstellung,

Fig. 10

eine vergrößerte Einzelheit A der Backofenmuffel gemäß Fig. 9,

Fig. 11 und 12

zwei Varianten einer Isolierschicht im Querschnitt.

It shows

Fig. 1

the perspective view of a domestic heating appliance in the form of an oven muffle,

2 and 3

two different occupancy variants of an oven muffle with film layers in a schematic representation,

Fig. 4

an oven muffle with unwound insulation formed from several coherent layers of film,

5 to 7

a simplified representation of the edge area of one or two film layers and the configuration of the edge or edge section.

Fig. 8

a plan view of a film layer edge or edge section,

Fig. 9

the top view of an oven muffle with this enveloping, formed as a film layer insulation in a sectional view,

Fig. 10

8 shows an enlarged detail A of the oven muffle according to FIG. 9,

11 and 12

two variants of an insulating layer in cross section.

Fig. 1 shows a front view of the housing of a domestic heating appliance in the form of an oven muffle 1, the cuboid is formed and four perpendicular to each other Furnace walls 2, 3, 4 and 5 as well as a circumferential, bent furnace or feed flange 6 has. An air distribution shaft is arranged in front of the rear furnace wall 7 8 with corresponding fan 9 and air heating 10, causing heated air flows in the direction of the arrow in blown the equipment room inside the oven muffle 1 can be. Arranged on the top furnace wall 3 is an internal radiant heater 11 while below the lower furnace wall 5 an external radiator 12 is arranged as a so-called bottom heat.

In the exemplary embodiment according to FIG. 2, again 1 called a slightly changed oven muffle in cross section without showing the loading flange 6 according to Fig. 1. Here are the furnace walls 2, 3, 4 and 5 adapted in terms of shape surrounded by four film layers 13, the configuration of which is explained in more detail below. Each film layer 13 has edges made of the films self-formed, bendable and fastening and / or connecting elements Representing edges 14, which have the outer dimensions protrude the oven muffle 1 and after the form-fitting application of the respective film layer 13 on the outside of the oven muffle 1 in Arrow direction folded onto the adjacent film layer become. Due to the mutual overlap of the film layers 13 there is a complete thermal insulation of the relevant furnace walls. In the embodiment 3 are for the insulation of the furnace walls Oven muffle 1 only two longer layers of film 13a provided in the middle of the side furnace walls 2 and 4 butt together and their edges 14 bent outwards and in the direction of the arrow on the respective Foil layer 13a are folded back or according to the dotted outline protrude outwards.

4 is again schematic the front view of an oven muffle 1 canceled Shown loading flange 6 shown, with the Insulation of the aforementioned furnace walls a one-piece film layer sheet 15 is used, the four by compressed edge sections 16 separate film layers 13b and has cantilevered edges 14 at both ends. This film layer web 15 is wrapped around the aforementioned furnace walls, the compressed edge sections 16 in the Corner areas of the oven muffle 1 curved connecting elements represent.

5 is a part of an enlarged view Foil layer 13 with associated edge 14 or edge section 16 shown when trained as a film layer web. This layer of film 13 is multi-layered and consists e.g. from four aluminum foils a, b, c and d, with foils a and d outer Show cover foils. The inner foils have b and c in the exemplary embodiment e.g. a meandering expression and are arranged crosswise to each other, i.e. the meandering and elongated embossing 17 stand perpendicular to each other and touch each other point by point. This Embossing points 17 represent spacing elements, which the in Example multilayer films a, b, c and d around a predetermined one Keep the distance between them. In the area the foils are placed directly on top of one another at their foil edges and at least approximately airtight due to compression locked. This compression can be done by multiple, partial deep drawing of the film composite in the area of deep-drawing points 18 according to FIGS. 6 and 7, but not all slides are drawn. By subsequent Squeezing the deep-drawing points 18 creates a flat edge 14, the film edges of which are permanently attached to one another, 7 shows. The deep-drawing and squeezing points can such as a Z-shaped, mutually overlapping profile according to the top view in FIG. 8.

FIG. 9 shows the oven muffle 1 in somewhat more detail Horizontal section, the front of the loading flange 6 has. It can be seen that on the outside the side furnace walls 2 and 4 layers of film 13b, e.g. Part of a one-piece film layer web could be. The film layer used here 13b is illustrated in more detail in FIGS. 10 and 11. It consists of two outer cover foils a 'and d' and from two inner foils b 'and c'. The inner foils b 'and c' are in a regular pattern with embossing points trained cup-shaped spacers 19a and 19b provided, which support each other, whereby these multi-profiled foils b 'and c' so each other are assigned or placed on top of each other that the spacer elements 19a e.g. the film c 'with the spacer elements 19b of the film b 'meet in a supportive manner. These slides are designed the same. The spacing elements designated 19a preferably have on the support surfaces circular recesses 20 in which the contracting Immerse spacer elements 19b with their flat support surfaces and are held in a form-fitting manner. In this way a firm fixation of the film composite is achieved, so that even when the film layer 13c is bent honeycomb pattern remains. On top of that the cover foils a'and d 'in a similar way with a profiling is provided with elevations 21 on the one hand and depressions 22 on the other hand, being in the elevations 21 engage the flat support surfaces of the spacer elements 19b and are fixed. In the embodiment shown in FIG. 12, the honeycomb-shaped film layer pattern is further expanded by two more foils e 'and f', their design and arrangement is analogous to that shown in FIG. 11 Foil layer 13c. Through the cup-shaped spacers 19a and 19b become one between the cover foils a 'and d' Variety of air chambers 23 are formed, the edge side in the described way e.g. through the edges 14 or edge portions 16 are closed. In the embodiment according to 9 and 10 is the film layer 13c on one Side border 14 bent by 180 ° and thermally closely and directly on the inside 24 of the charging flange 6 coupled or attached relatively large area. Esp. then when the directly on the oven muffle 1 attached cover sheet e.g. a 'from a highly heat-resistant Material like sheet steel with a slightly larger cross-section is formed, one reaches one in this way intensive drainage in the area of the feed flange 6 when the oven is in operation, especially in the pyrolytic self-cleaning mode with operating temperatures of around 500 ° C heat generated and thus a reduction in the flange temperature. It also has some control over the heat distribution as well as a small area direct coupling the inner cover sheet a 'to the oven muffle 1 e.g. on the furnace wall 4 achieves that only the elevations 21st the film layer 13c or the cover film a 'in immediate Make contact with the muffle wall 4 while between these elevations 21 in the region of the depressions 22 air chambers 25 are formed. As illustrated in Fig. 9, be provided that e.g. in the side furnace wall 2/4 there is an expression with a cutout 26 e.g. for accommodating an oven lighting device. More like that Way as with the feed flange 6 can also here the edge 14 of the film layer 13c must be bent and immediately for heat dissipation on the outside wall of the expression 26 be attached. For this purpose, the film layer 13c is e.g. with a circular or elongated recess 27 provided, which is limited by the peripheral edge 14.

FIG. 13 essentially shows the structure according to FIG. 11 or 12. Here are between the touch or Support points, i.e. the recesses 20 of the profiled film e 'and the flat supporting surfaces of the neighboring, upper Foil b 'intermediate layers 30 from a heat poorly conductive Material, which makes the two films mentioned thermal are largely decoupled from each other. Of course can also with a wave-like shaping of the films or intermediate films e.g. such intermediate layers according to FIG be provided, which then e.g. elongated, stripe-shaped are formed, while in Figure 13 in the form of round Discs are executed.

In the exemplary embodiment according to FIG. 14 there is between two Cover foils a and c are essentially wavy or meandering film b arranged as a spacer, the elongated with overlapping each other Perforations or cutouts 31 are provided continuously, whereby the mass of this intermediate film b is reduced by approximately 90% is. In this simple way, heat conduction largely prevented between the cover foils a and c and you get a weight reduction of the film layer.

Within the scope of the invention there is the possibility of the number to vary the foils within a foil layer accordingly the thermal load from the insulation Heat domestic appliance runs out in whole or in part. It exists also the possibility to use other materials instead of aluminum, e.g. also use heat-resistant plastics. The use of highly heat-resistant material e.g. Stole, Stainless steel or the like for at least the inner cover film is useful if the appropriate film layer immediately a radiator e.g. the outside Bottom heat 12 according to FIG. 1 covers. The edges or border areas of the film layers can also e.g. by welding be hermetically sealed or compressed.

Claims (19)

1. Household heating appliance, in particular household appliance, for example baking oven, the appliance chamber of which includes at least one heating element and is at least partially surrounded by at least one multiple layer of air-tight foils which are connected one with the other at least at the rim side and enclose air chambers and which for the remainder are held at a mutual spacing one from the other, characterised in that the at least one foil layer (13) at all sides has a rim (14), which is formed of the foil rims and closed off to be air-tight and which forms a flexible fastening and/or connecting element.
2. Household heating appliance according to claim 1, characterised in that the foil layer (13) consists of a unitary material, preferably of aluminium foil material.
3. Household heating appliance according to one of the preceding claims, characterised in that the appliance chamber is at least partially surrounded by several foil layers (13), which are insulated one against the other in air-tight manner.
4. Household heating appliance according to claim 3, characterised in that the foil layers have differently many foils.
5. Household heating appliance according to claim 3, characterised in that the foil layers (13b) are components of a common foil layer web (15) interrupted aero-dynamically one from the other by closed rim portions (16).
6. Household heating appliance according to claim 3, characterised in that the directly adjoining foil layers overlap at the boundary regions.
7. Household heating appliance according to claim 3, characterised in that neighbouring foil layers abut directly one against the other and their rims (14) are bent away from the place of abutment (Figs. 2 and 3).
8. Household heating appliance according to claim 3, characterised in that the individual foils (a, b, c, d) of the foil layer (13, 13c) are kept at a mutual spacing one from the other by stamped foil places forming spacer elements (17; 19a, 19b) of small area.
9. Household heating appliance according to claim 8, characterised in that the foil layer (13) consists of at least three foils, wherein the at least one foil (b, c) lying between the outer cover foils (a, d) has stamped places forming spacer elements (19a, 19b).
10. Household heating appliance according to claim 9, characterised in that at least two foils (b, c), which are provided with meander-shaped stamped places standing one on the other in crossed manner, are arranged between the cover foils (a, d, Fig. 5).
11. Household heating appliance according to claim 9, characterised in that the inwardly lying foils have substantially bowl-shaped spacer elements (19a, 19b), which are directed one against the other and bear one against the other preferably in honeycomb shape.
12. Household heating appliance according to claim 11, characterised in that those support surfaces of the spacer elements (19a), which are parallel to the plane of the foil layer (13c), comprise a foil with preferably circular depressions (22), in which the support surfaces of small area of the neighbouring foil or foils are retained shape-lockingly.
13. Household heating appliance according to claim 9, characterised in that at least one of the cover foils (a', d') is provided with protrusions (21) and depressions (22) by profiling of the surface.
14. Household heating appliance according to one of the preceding claims, characterised in that the rims (14) and/or rim portions (16) of the foils are clawed together at deep-drawn and preferably squeezed places engaging one behind the other.
15. Household heating appliance according to claim 14, characterised in that the rims (14) and/or rim regions (16) have several, preferably mutually overlapping clawed-together places (Fig. 8).
16. Household heating appliance according to one of the preceding claims, characterised in that the connection at the rim of the foils is realised by welding.
17. Household heating appliance according to claim 9, characterised in that at least one of the cover foils (a') consists of a highly heat-resistant material such as sheet steel plate or fine sheet steel plate.
18. Household heating appliance according to one of the preceding claims, characterised in that at least one of the rims (14) or rim portions of the foil layer (13c) or foil layers is closely coupled thermally to thermally highly loaded regions or to regions, which are to be relieved thermally, of the housing which forms the appliance chamber.
19. Household heating appliance according to claim 18, characterised by the edge coupling at the charging flange (6) of the housing.

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