DE202014004182U1 - Furnace muffle with glass or glass ceramic wall elements connected with metallic components - Google Patents

Abstract

Oven muffle, in particular oven muffle, with at least one wall element consisting at least partially of glass or glass-ceramic, which at least partially delimits an interior serving in particular as a cooking space, characterized in that the glass or glass-ceramic of the wall element has at least one integral connection with at least one component made of a metallic material is connected.

Description

The invention relates to a furnace muffle, in particular baking oven muffle, with at least one at least partially made of glass or glass ceramic wall element which limits an interior serving in particular as a cooking space at least partially, wherein the glass or the glass ceramic of the wall element is connected to at least one component made of a metallic material ,

Electrically heated ovens for stoves or for installation in a kitchenette are well known. The oven consists essentially of a baking oven muffle, which is heated at the top and bottom with tubular bodies. At the front, the oven muffle is closed with a framed glass door. Usually, the upper heating is arranged in the interior of the baking oven muffle and is supported in high-quality ovens by a second radiator, which allows a grill function of the oven. The lower radiator is arranged on the outside of the muffle floor. In addition to these standard heaters for top / bottom heat and grill operation, a circulating air blower is often still used in the rear wall, which can also have a separate heating ring, not only to circulate air, but also to generate even hot air.

Many oven mufflers, in particular oven muffles or muffles of microwave ovens or steamers, have viewing windows, generally in the door. That's the way of view doors. They allow the outside of the view into the muffle interior. In the case of glazed doors, in contrast to the other wall elements delimiting the muffle interior, effective thermal insulation is made more difficult. That is why glazed doors heat up on their outside more than the housing over the walls bounding the interior. Usually, glazed doors consist of frames, usually metallic frames, and usually several panes, which are attached to the frame, the door panel. The handle for closing and opening the door is usually attached to the door frame or is part of the door frame. The handle can also be attached to the windscreen. He may be screwed through holes through the disc with the frame, for example. The hinges for opening and closing the door, generally in the form of a hinged door, are attached to the frame.

It is known that holding devices are formed as metallic holding grid in a cooking chamber of a baking oven, which are mounted on vertical side walls of a muffle, which limits the cooking space. These holding grids are used to hold other components, such as a rail extension system, such as a telescopic rail. On this telescopic rail then a food support such as a grid, a fat pan or a baking sheet, can be placed. Two identically designed holding devices on opposite vertical side walls of the muffle make it possible for the food support to be positioned correspondingly on both sides. It is known that the holding devices can be attached directly to the muffle wall via corresponding bushing suspensions. The attachment of a holding device is often quite complex and limited with respect to the mechanical stable support. EP 2 703 736 A1 proposes here an improved solution.

It is known to make oven walls made of glass or glass ceramic.

The use of glass ceramic in ovens is already in the CA 2,183,498 described.

In DE 35 27 957 C2 an oven muffle is described glass ceramic, which is detachably joined together and which is heated by externally heated radiant heaters.

DE 35 27 958 C2 describes an enamelled steel sheet muffle, in which window openings are provided in the side walls, are inserted into the glass or glass ceramic panes.

DE 10 2008 025 907 describes a furnace muffle with the interior limiting wall elements, of which at least two adjoining wall elements made of glass or glass ceramic.

In particular, due to the high temperatures in the muffle interior, the design possibilities of Muffelraumkomponenten and design elements are limited both in terms of their choice of material and in terms of their attachment.

Thus, the described metallic holding devices can be realized on the muffle side walls, for example in steel muffles, but not on glass or glass ceramic wall elements, since suitable mounting options are missing. This is where the invention comes in order to remedy the situation.

The glass or glass-ceramic materials of the at least partially existing wall elements for oven muffles usually have low thermal expansion coefficients, in particular coefficients of expansion α (20 ° C - 300 ° C) between -1.0 × 10 ^-6 / K and +4.0 × 10 ^-6 / K.

To brittle materials such as glass or glass ceramic with metallic To connect materials, various possibilities are described in the prior art.

One possibility is to constructively produce the desired bond between a brittle material and a metallic material, for example by clamping or bolting. Here, however, there is a disadvantage in that the different thermal expansions in the components involved, in particular the Verschraubungskomponenten, can not be sufficiently compensated so that fracture-relevant stresses in the brittle material are reliably avoided. Another disadvantage of a constructive bond of brittle material and metallic material are far-reaching restrictions on the possible geometric design of the compound.

Special requirements arise from the use in the high temperature range that prevails in the oven muffles. Depending on the use, for example as a drying oven, or oven, possibly even as a pyrolysis oven, occur in the interior of the oven muffle temperatures of 50 ° C to 600 ° C.

Another challenge in the use of completely or partially consisting of glass or glass ceramic wall elements in oven mufflers is that, for example, in pyrolysis ovens the wall element and thus its fasteners or similar temperature changes with a temperature difference of more than 230 K, are exposed. In such cases, there is a risk that the bodies will break at the junction.

The object of the invention is thus to provide a furnace muffle with wall elements with glass or glass ceramic components with a stable, especially temperature-stable connection with a component made of a metallic material.

This object is achieved by a furnace muffle according to the protection claim 1.

Essential is the cohesive connection.

It can be realized in different ways. The application oven muffle also means high demands on its temperature stability for the cohesive connection. However, the concrete requirements depend on the specific position of the material connection on the oven muffle, namely on the thermal, mechanical and chemical load acting on it. The person skilled in the art knows how to select the suitable production method according to the requirements.

An advantage of a cohesive connection is an easier to implement tightness of the cooking chamber, as can be dispensed with holes for attaching elements, this is interesting, for example, in appliances with Dampfgarfunktion.

Another advantage of a cohesive connection over a positive or non-positive connection, in which a hole in the glass or glass ceramic plate is necessary, is the reduced space requirement, since no counter element on the back of the plate is needed.

In order to solve the problem of thermal shock resistance, the use of components made of metallic materials, which are largely adapted to the glass or the glass ceramic in the desired application in terms of their expansion behavior, is described in the prior art. Here, however, problems arise in the temperature range above 250 ° C.

Another possibility, discussed in the prior art, consists in the integral connection by means of a bonding of metallic material and brittle material, wherein the adhesive, due to its elastic property, compensates for the different thermal expansions of the materials to be joined. Examples of such adhesives in the prior art are, for example, silicone adhesives. A disadvantage of such a cohesive connection, however, is that the temperature resistance is usually limited to temperatures less than 250 ° C. There are also adhesives known that can withstand more than 300 ° C, but only for a limited time. There are also known adhesives which are long-term stable at the temperatures mentioned, but which are not suitable for the present material pairings.

Another possibility of a cohesive connection is to lower by means of intermediate glasses or glass solders the stresses arising in the connection between the brittle material and the metallic material. However, in such a solution, it should be borne in mind that the difference in the thermal expansions of the brittle material and metallic material can no longer be compensated for temperature changes of more than 250 K.

As a suitable method for producing a cohesive connection according to the invention between the glass or the glass ceramic of the wall element and a component made of a metallic material, the soldering, in particular the ultrasonic soldering, as for example in the DE 10 2012 204 235 A1 is described.

A particularly suitable method for producing a cohesive connection according to the invention between the glass or the glass ceramic of the wall element and a component made of a metallic material is welding, in particular ultrasonic welding. The ultrasonic welding takes place in the usual frequency range from 15 to 50 kHz, preferably at 20 to 40 kHz, particularly preferably at 20 kHz or at 40 kHz. It leads to high-temperature-stable compounds that can withstand the operating temperatures occurring in the interior of a furnace muffle.

Regarding the ultrasonic welding method is applied to the DE 199 17 133 A1 referenced, in detail the welding of a workpiece made of glass, glass ceramic and / or ceramic, that is, a brittle, inorganic, poorly heat-conductive material with low long range order and a workpiece thereof from various material, such as a metal is described. The disclosure of the DE 199 17 133 A1 is fully incorporated in the present application.

The welding, in particular with ultrasonic welding apparatuses, between the glass or the glass ceramic of the wall element and the component of metallic material takes place between a first connection surface on the glass or the glass ceramic of the wall element and a second connection surface on the component made of metallic material. Between the first and second connection surface an intermediate layer is introduced. The welding can be carried out flat or even partial area, wherein a partial area welding depending on the geometry of a spot welding, a seam welding or torsional welding can be.

In this embodiment, it is thus provided that the connection of glass or glass ceramic of the wall element and component of metallic material comprises an intermediate layer between glass or glass ceramic of the wall element and the metallic material, in particular an intermediate layer of a ductile metal. The intermediate layer ensures that the connection between glass or the glass ceramic of the wall element and the metallic material is produced. Furthermore, stresses that arise between the glass or the glass ceramic of the wall element and the metallic material can be at least partially reduced by the intermediate layer. In the present application, ductile metals are understood as meaning those having an elongation at break ≥ 1%, preferably ≥ 10%, in particular in the range from 1% to 20%, preferably from 2% to 15%.

Particularly preferred materials having such an elongation at break are, for example, the pure aluminum foil Al 99.5 - smooth, soft, bright rolled - ALUJET from the company ALUJET GmbH, Ahornstraße 16, D-82291 Mammendorf, which at a thickness in the range 0.05 mm to 0, 30 mm has an elongation at break transversely ≥ 4% and an elongation at break of ≥ 4%, or an aluminum foil 7800 from 3M Germany GmbH, Carl-Schurz-Str. 1, D-41453 Neuss, which also has an elongation at break ≥ 4% at a film thickness of 0.05 mm.

In this embodiment, a portion of the stresses is elastically degraded by the intermediate layer, above 100 ° C by flowing, but it can remain residual stresses.

A particularly preferred embodiment consists in that the glass ceramic or the glass is a material having a thermal coefficient of linear expansion α (20 ° C.-300 ° C.) ≦ 4 × 10 ^-6 / K, in particular in the range -1.0 × 10 -4 ^{. 6} / K ≦ α ≦ 4 × 10 ^-6 / K, particularly preferably -0.6 × 10 ^-6 / K ≦ α ≦ 2 × 10 ^-6 / K.

Exemplary materials having a thermal expansion coefficient in this range are Li-Al-Si glass ceramics such as glass ceramics ROBAX ^®, ceramic ^® and Nextrema ^® of the company Schott AG, Mainz, having a coefficient of thermal expansion in the temperature range from 20 ° C to 300 ° C in the range of -0.3 to 1.0 x 10 ^-6 / K have. The glass ceramics used can be transparent, translucent or opaque. They can be colorless or colored.

As a glass material, for example, a borosilicate glass can be used depending on the type and type of heating and the position of the glass material, e.g. B. Borofloat33 ^® or Borofloat40 ^®. The glass material Borofloat33 ^® has a thermal coefficient of linear expansion α (20 ° C - 300 ° C) of 3.3 10 ^-6 / K. The glass material Borofloat40 ^® has a thermal coefficient of linear expansion α (20 ° C - 300 ° C) of 4.0 10 ^-6 / K.

Depending on the type and type of heating and the position of the glass material, for example the green glass, ie the non-ceramised material, can be used as the glass material in accordance with the compositions of the cited glass ceramics. It has a thermal expansion coefficient between 3.8 × 10 ^-6 / K and 4.2 × 10 ^-6 / K.

Glass-ceramics are preferred for use as a furnace muffle wall element because of their superior thermal resistance to glasses. Glass ceramics are particularly suitable for applications in the oven muffle with maximum temperatures on the disc above 280 ° C and maximum temperature gradients on the disc over 145 K better than glasses. In oven doors, glass panes are often used as windscreen Glass ceramic discs used. As inner panes, in particular in pyrolysis ovens, glass ceramic panes are preferred.

It is also possible to combine glass ceramic elements with glass elements.

As a metallic material for the component of metallic material is preferably a metallic material having a coefficient of thermal expansion α in the temperature range 20 ° C to 300 ° C, for which applies: α ≤ 20 · 10 ^-6 / K, in particular in the range 4.0 · 10 ^{- 6} / K ≦ α ≦ 6 × 10 ^-6 / K. A particularly preferred metallic material is KOVAR. Alternatively, molybdenum, steel, tungsten or stainless steel are possible. KOVAR is an iron-cobalt-nickel alloy.

It is particularly preferred if the metallic material is selected depending on the glass or glass ceramic material in such a way that the metallic material has a thermal coefficient of linear expansion α (20 ° C - 300 ° C) in the range α _{(glass or glass ceramic)} - 10 · 10th ^-6 / K ≤ α ≤ _{(glass or glass ceramic)} + 10 · 10 ^-6 / K, preferably α _{(glass or glass ceramic)} - 8 · 10 ^-6 / K ≤ α ≤ α _{(glass or glass ceramic)} + 8 · 10 ^{- 6} / K, in particular α _{(glass or glass ceramic)} - 5 × 10 ^-6 / K ≦ α ≦ α _{(glass or glass ceramic)} + 5 × 10 ^-6 / K.

A body or composite comprising the glass or glass-ceramic material and the metallic material surprisingly exhibits a permanently temperature-resistant compound above 250 ° C., in particular above 300 ° C., despite the different thermal expansions of the two joining partners. Particularly preferably, the permanent temperature resistance up to temperatures of 400 ° C, particularly preferably up to 500 ° C, achieved. Even temperature changes of over 250 K, the compound thus prepared withstand, even if the brittle material has a low or zero expansion.

According to the invention, an intermediate layer is introduced between the glass or glass-ceramic material and the metallic material. The intermediate layer preferably consists of a ductile metal, preferably of aluminum, in particular high-purity aluminum or else also gold or a gold alloy. The thickness of such an intermediate layer is preferably in the range of 50 μm and 200 μm.

In addition to the intermediate layer, it is possible to pretreat the first and / or second connecting surface, in particular if it is connected by means of ultrasonic welding as a joining method. This is particularly advantageous for the glass or glass ceramic material. In question, for example, come thermal or chemical toughening or a strength-enhancing coating. Surprisingly, it has also been found that an improvement in the temperature and / or thermal shock resistance can be achieved by local and / or full-area etching or polishing of the bonding surface of the glass or glass-ceramic material. The connection of glass or glass ceramic material and metallic material by means of ultrasonic welding can be done very quickly. Thus, such a connection can be made by spot and / or torsional welding in short times. Times of less than 10 seconds are possible, preferably less than 5 seconds, in particular even less than 1 second.

The furnace muff according to the invention with a wall element consisting at least partially of glass or glass ceramic with at least one cohesive connection with a component made of a metallic material is preferably produced as follows:
First, a glass or a glass-ceramic is preferably having a thermal expansion coefficient α (20 ° C - 300 ° C) ≤ 4 · 10 ^-6 / K, in particular α (20 ° C - 300 ° C) ≤ 2 · 10 ^-6 / K , preferably in the range -1 × 10 ^-6 / K, ≦ α ≦ 4 × 10 ^-6 / K, in particular in the range -0.6 × 10 ^-6 / K ≦ α _brittle ≦ 2 × 10 ^-6 / K, for example a Li-Al-Si glass-ceramic provided with a first bonding surface.

In contrast, a metallic material having a thermal coefficient of linear expansion α in the temperature range from 20 ° C. to 300 ° C., for which α (20 ° C. -300 ° C.) ≦ 20 × 10 ^-6 / K, in particular in the range 4 × 10 ^-6 / K ≤ α ≤ 6 · 10 ^-6 / K, for example KOVAR, provided with a second interface.

Then, the glass or glass-ceramic material with the metallic material firmly in the region of the first and second bonding surface via an intermediate layer which is introduced between the first and second bonding surface, the intermediate layer preferably of a ductile metal, in particular aluminum, preferably pure aluminum, an aluminum alloy , Gold or a gold alloy, preferably with a thickness between 50 microns and 200 microns, connected together. As a result, a high temperature resistant compound for temperatures of more than 250 ° C, preferably more than 300 ° C and / or a thermal shock resistance of more than 250 K, provided.

The brittle-glass or glass-ceramic material is connected to the metallic material by a joining process, in particular welding, in particular ultrasonic welding, preferably in the form of spot welding, seam welding or torsion welding.

Particularly high-temperature resistant compounds, in particular with regard to thermal shock resistance, are achieved when, in particular, the first bonding surface of the glass or glass ceramic article is treated. Here it is possible biasing, smoothing, nubs, structuring, partial or full-area etching, polishing and / or ion exchange.

The oven muffle according to the invention may have one or more cohesive connections between a wall element and a component. Preference is given to several compounds.

It is preferred that the furnace muff according to the invention has at least two wall elements at least partially, preferably made entirely of glass or glass ceramic, and / or that it has at least two components of metallic material.

The oven muffle according to the invention may have cohesive connections between a wall element and more than one component. More than one compound per component is preferred.

The oven muffle according to the invention may have cohesive connections between a component and more than one wall element. More than one compound per wall element is preferred.

The wall element is preferably formed in a plate shape.

The plate may have the one or more cohesive connections on the top or on the bottom or on the narrow edge surfaces, the side surfaces of the plate.

The plate may be flat or partially deformed or formed partially changed in its thickness, material structure or surface structure.

The plate may be bent, in particular in the form of a cylinder surface or a spherical surface segment.

The cohesive connection may be formed flat or part-surface, wherein in a ultrasound-welded connection, the partial area connection is preferred. In the case of part-area welding, the ratio between welded contact surface (vK) and non-welded contact surface (nvK) is preferably less than 1.

The cohesive connection can be formed between uncoated surfaces; the integral bond can also be formed between surfaces, one or both of which are coated. When both surfaces are coated, the coatings may have the same or different compositions.

By virtue of the invention, glass or glass ceramic plates which consist of a plurality of segments or modules can be connected to one another by means of metallic connecting elements, in particular connecting strips, which are materially connected to the plate segments or modules. This is particularly advantageous where the contact area is exposed to elevated temperatures and therefore silicone adhesives can not be used.

The connection strips consist for example of steel, esp. Stainless steel, aluminum or enamelled sheet metal.

In this case, a wall element may be modular or segmental and composed as described. Or two or more wall elements can be connected via connecting elements, in particular connecting strips, via integral, preferably welded, preferably ultrasonically welded, in particular part-area connections and thus at least partially open up a space, the interior of the oven muffle.

Thus, a furnace muffle with three lateral wall elements made of glass or glass ceramic, a bottom plate and a ceiling plate made of glass or glass ceramic as further wall elements and as the last wall element of a door made of glass or glass ceramic possible, of which except for the door element, the respective adjacent elements via connecting strips are connected cohesively. It is also possible to connect only certain wall and / or ceiling and / or floor panels made of glass and glass ceramic, while other wall and / or ceiling and / or floor panels made of glass and glass ceramic with conventional furnace muffle materials such as steel enamel connected are

By means of the invention it is also possible to realize connections of frames, frame segments and frame borders with the glass or glass ceramic plate. Preferably, the cohesive connections, with which these compounds are realized, formed only part of the surface.

These frames and frames are also particularly useful where the contact area is exposed to elevated temperatures and therefore silicone adhesives can not be used.

In particular, when the frame or the frame segment extends over a side surface of the Plate extends to its top and bottom, it serves as edge protection.

Thus, a glazed door can be realized with a glass or glass-ceramic viewing window and a metal frame.

The glazed door can be connected via hinges to the oven muffle. The hinges can be connected via the metal frame with the oven muffle. According to the invention, the hinges can be connected via at least one cohesive connection to a wall element of the oven muffle adjoining the door and / or to the glass or the glass ceramic of the wall element door.

The hinges are preferably made of steel, esp. Stainless steel, aluminum or enamelled sheet metal.

Other possible mounting elements which can likewise be used in accordance with the invention are clips with clip receptacles, bolts, clamps, screws, nuts, eyes or hooks. But also handles, for example door handles, in various embodiments, for example in toggle or handle form, can be connected via the integral connection to the glass pane. or glass ceramic plate fastened. The mounting elements mentioned here offer, as an adapter welded on the glass ceramic, also the ability to easily attach the metal elements to be connected such as spacers, metal cover, metal strips o. Ä. On the glass ceramic.

The glazed door can have more than one pane, preferably it has a front and an inner pane. This improves the thermal insulation of the open muffle. The inner pane is preferably made of glass ceramic and the front pane is made of glass. A third or even fourth central disk is also preferred, for example in pyrolysis furnaces. Thus, the thermal insulation of the open muffle is further improved. The disks can be connected to one another via spacers according to the invention. The spacers can be selectively, so partially, or circumferentially mounted. Preferably, they are mounted close to the wafer edge. The cohesive connections can be formed fully or partially. Partial area connections are preferred

The spacers are preferably made of steel, esp. Stainless steel, aluminum or enameled sheet metal.

Such a disk package with within the oven door via spacers selectively or circumferentially connected discs of glass ceramic or glass if necessary has the advantage of ease of installation and a high thermal insulation effect. The latter especially when air flow is prevented by a circumferential seal, with a small air outlet overpressure in the disk package is prevented when heated. Thus, the oven muffle facing glass ceramic side gets hotter, which improves the pyrolysis effect in the oven and on the glass ceramic.

In oven muffles, such as oven muffles, with circulating air blowers, possibly also with additional heating ring, can be realized by the invention preferably a compound of the circulating fan and / or its metallic cover with the preferably at least partially made of glass ceramic wall element of the oven muffle. Preferably, such fans are mounted on the back wall of the oven muffle, but other positions are possible.

Also, the attachment and fixation of heating elements such as heating coils is possible via cohesive connections of the at least partially made of glass ceramic wall element of the oven muffle with one or more metal elements, which in turn are attached to the heating element. Such a heating element is preferably arranged on the wall or wall forming the rear wall or a side wall.

It is also possible to combine glass-ceramic elements with glass elements by connecting them via integral connections with metal elements, for example rails. For example, recesses in a glass ceramic plate can be covered with a glass pane connected in this way. In particular, in this way transparent glass elements, in particular plates, can be connected to non-transparent glass ceramic elements, in particular plates, so that they form viewing windows in the wall elements.

The invention will be described below with reference to the figures. Show it

1 in a sectional view of a double pane of a baking oven door, the front and inner pane are connected to each other via a material connection with a spacer and are kept apart from each other,

2 in a sectional view of a rear wall of a baking oven muffle, on each of which via a cohesive connection a fan and its metal cover are mounted,

3 the holder of a heating element of a baking oven muffle, in which the heating spiral is materially connected via a metal holder to the glass ceramic plate as a wall element of the oven muffle,

4 a perspective view of a baking oven muffin with a oven door, which is connected via hinges with the muffle,

5a to 5c various types of connection that can be realized by using a metal element that is bonded to the glass or glass ceramic object,

6 a perspective schematic representation of a furnace muffle interior, in which on a wall element inside a baking sheet holder is fastened by means of screwing on cohesively connected to the wall element metal elements,

7 in a sectional view of a rear or side wall of a baking oven muffle, in which by means of material connection via a metal element, a glass element is embedded.

8th a perspective view of a baking oven muffle, are realized on the various embodiments of inventive cohesive connections.

In 1 is a sectional partial view of a oven door with a glass ceramic disc as an inner pane 1.1 and a glass pane as a windshield 1.2 shown. Both plates are firmly bonded to the metallic spacer 1.3 connected. The spacer may also be mounted on one or more mounting elements, which are materially connected to the glass ceramic. The cohesive connection is preferably produced by welding, in particular ultrasonic welding. The glass ceramic plate 1.1 may consist, for example, without limitation, of a Li-Al-Si glass ceramic, in particular ROBAX ^® of the company Schott AG, Mainz. Such substantially zero-expansion material has a mean thermal expansion coefficient α (20 ° C-300 ° C) <0.15 × 10 ^-6 / K. The glass plate 1.2 may, for example, without limitation, of a borosilicate glass, in particular Borofloat33 ^® or Borofloat40 ^® from Schott AG, Mainz. Such a material preferably has an average thermal expansion coefficient α (20 ° C.-300 ° C.) of 3.3 × 10 ^-6 / K to 4.0 × 10 ^-6 / K, in particular of 3.3 × 10 ^-6 / K or 4.0 × 10 ^-6 / K. In the metallic material of the spacer 1.3 or the mounting member is essentially a metallic material having a thermal expansion coefficient α (20 ° C - 300 ° C) ≤ 20 · 10 ^-6 / K in the temperature range of 20 ° C to 300 ° C, preferably <6 × 10 ^-6 / K. The spacer 1.3 For example, it is made of steel, enamelled steel, stainless steel, aluminum or Kovar, with Kovar being preferred. The spacer is attached to the outer edge of the discs for design reasons. He is trained all around. Even partial training, so spacer segments are possible. It is also possible that the spacer is designed for better thermal insulation as a hollow body.

It is also possible that in the spacer heat-insulating materials are integrated.

In 2 is a sectional view of a rear wall of a baking oven muffle shown. The back wall 2.1 made of glass ceramic has an opening. Behind her is a schematically depicted fan 2.2 arranged, via a material connection with the rear wall 2.1 connected is. The fan housing can also be mounted on one or more mounting elements, which are materially connected to the glass ceramic. The fan is covered by a metal cover 2.3 covered, which also has integral connections with the rear wall 2.1 is connected or mounted on one or more mounting elements, which are materially connected to the glass ceramic. Preferably, the cohesive connections were produced by ultrasonic welding.

In 3 is the holder of a heating element of a baking oven muffle shown. The heating element is preferably arranged on a side wall or on the rear wall of the oven muffle. The glass ceramic plate 3.1 as a wall element of the oven muffle is connected via a cohesive, preferably produced by means of ultrasonic welding, connection with a metal holder 3.2 connected to the heating coil 03.03 of the heating element is attached. So the Heizspiralelement can be fixed. This succeeds particularly well if the connection is realized via more than one metal element, for example via two or three or even four or five metal elements.

4 shows a perspective view of a baking oven with a oven door. The oven door with a glass ceramic door inner pane 4.1 is about two metal hinges 4.2.1 and 4.2.2 with the front part 4.3 connected to the oven muffle. The hinges 4.2.1 and 4.2.2 are preferably made of steel, enamelled steel, stainless steel, aluminum or more preferably made of Kovar and are about inventive cohesive compounds, which were preferably produced by ultrasonic welding, with the inner door panel 4.1 connected. The front part 4.3 can be made of metal, for example steel, enamelled steel, stainless steel, aluminum or Kovar, or glass ceramic or glass. If it consists of glass ceramic or glass, the hinges can also be connected to this component via integral connections according to the invention. On the outside of the door is a metal door handle, such as steel, enamelled steel, stainless steel, aluminum or Kovar, attached. Also, it can be attached directly to the outer pane of glass ceramic or glass via a material connection according to the invention. To accommodate the hinges or the door handle, it is possible to connect only adapter plates or angle cohesively with the glass ceramic disk, in which the hinges or the door handle are then releasably or permanently locked. This ensures easy assembly and disassembly of the oven door.

In 5a to 5c are shown schematically different types of connection, in which initially a glass or glass ceramic plate 5.1 with at least one metallic element 5.2 is connected cohesively. Preferably, the cohesive connection was produced by welding, particularly preferably by ultrasonic welding. The cohesive connection may be formed over the entire surface or part of the area, preferably it is part of the surface formed.

In 5a is the metallic element 5.2a , which is attached to the glass ceramic plate by means of material connection, a button or rivet-shaped element, such as Kovar, on the one metal rail 5.3a can be pushed. The element can be presented by machining such as turning or milling, by forming such as deep drawing or bending or pressing or by cutting machining such as punching. Preferably, namely to ensure better guidance of the rail, the use of more than one of these metal elements 5.2a , Preferably, the metal rail is made of the same material as the metal element.

5b is a sectional view showing a more specific embodiment of 5a known metal rail with metal element shows. Due to the special shape of the metal element 5.2b that conform to the shape of the metal rail 5.3b adjusted, the rail can not only be postponed, but also clipped on. For this type of fastening rails and metal elements made of Kovar are preferred. Such a Klips- / plug connection allows a particularly simple installation. The metal element may be presented by machining such as turning or milling, by forming such as deep drawing or bending or pressing, or by cutting such as punching. 5c also shows in sectional view an alternative connection possibility, in which with the glass ceramic plate 5.1c cohesively connected element 5.2c with another metal element 5.3c is screwed. That's the element 5.2c a metal element with blind hole into which a mounting plate 5.3c inserted from steel and with a screw 5.4c was screwed. Also other versions of the metal element 5.3c are conceivable, for example, those with external thread or thread with through hole through the metal element.

The element can be presented by machining such as turning or milling, by forming such as deep drawing or bending or pressing or by cutting machining such as punching.

In 6 are on the wall element inside 6.1 of oven muffle interior two metal elements 6.2.1 and 6.2.2 attached via a cohesive connection. On them a baking sheet holder is screwed. Thus, the mounting of sheet metal and rust holders compared to conventional fasteners is enormously simplified. It is also possible to use more than two metal elements.

7 shows a sectional view of a rear or side wall of a baking oven muffle. The wall element consists of a non-transparent glass ceramic plate 7.1 , The glass ceramic plate 7.1 has a recess. The recess is made of a transparent glass element 7.2 covered. The glass element 7.2 is by means of cohesive, preferably produced by ultrasonic welding, connection with a metal element 7.3 connected, which also by means of cohesive, preferably generated by ultrasonic welding, connection to the glass ceramic plate 7.1 connected is. This creates a viewing window. If outside of the oven muffle in front of the window a lighting unit 7.4 , is attached, can be illuminated by the glass element, the interior of the oven muffle.

8th combines in perspective perspective various special embodiments of the oven muffle according to the invention. The wall elements 8.1 the oven muffle, incl. the ceiling element, are made of glass ceramic. The individual wall elements are over metallic connecting strips 8.2 connected with each other. The metallic connecting strips are connected to two wall elements via integral connections. The connecting strips can also be mounted on one or more mounting elements, which are materially connected to the glass ceramic. The material bond was preferably produced by means of welding, in particular ultrasonic welding. Through these connection strips, the discs can be tightly interconnected, even at operating temperatures where adhesive solutions with silicone adhesives fail. A heating element 8.3 is also fixed via a cohesive connection to the glass ceramic sidewall. The heating element may also be mounted on one or more mounting elements which are cohesively bonded to the glass ceramic are connected. In particular, radiant heating elements can be fastened directly on the outside of the glass ceramic. Inside the oven muffle interior are pull-out or insertion elements 8.4.1 and 8.4.2 made of metal materially connected to the wall elements. The pull-out or insertion elements can also be mounted on one or more mounting elements, which are materially connected to the glass ceramic. Thus, the direct connection between metal and glass ceramic is possible. And the installation of such rails or strips to which food supports such as gratings are attached, is greatly simplified compared to conventional fasteners.

The invention will be explained below with reference to the embodiments.

First embodiment of the production of a cohesive connection according to the invention by means of ultrasonic welding.

In a first embodiment, the brittle material consists of the glass ceramic ^Ceran® with a mean thermal expansion coefficient α _20-300 of -0.2 × 10 ^-6 / K. The surface intended for connection to a metallic molding is a surface formed in a rolling process with the nub structure known from the application as a cooking surface. The intermediate layer of ductile material is an aluminum foil EN-AW-1050A with a thickness of 0.1 mm for use. The metallic molded body consists of a 0.5 mm thick and 22 mm in diameter measuring flat base plate made of the material Kovar with a mean thermal expansion coefficient α _20-300 of 5.5 · 10 ^-6 / K. On the base plate centric and placed perpendicular to her is a firmly connected to the base plate threaded bolt with a height of 12 mm and a diameter of 8 mm for further mounting options according to the further application of the component according to the invention.

In a torsional ultrasonic welding process, the glass-ceramic Ceran, the intermediate layer of aluminum and the Kovar base plate are welded together using a sonotrode in the form of a hollow cylinder with frontal Rautierung, the front of the sonotrode touches the Kovar base plate and a torsional vibration performs. The sonotrode amplitude is 25 μm, the sonotrode frequency is 20 kHz, the welding pressure is 1.5 bar and the welding power is 500 Ws.

The composite body produced in this way has a connection between the nubbeads of the ceramic glass-ceramic in the contact region and the intermediate layer of aluminum, on the one hand, and at the same time a connection between the intermediate layer of aluminum and the kovar baseplate. A subsequent thermal stress caused by 100 temperature changes between room temperature 25 ° C and maximum temperature 350 ° C, the composite body without visible damage. A test of the resistance of the compound by a mechanical load test resulted in a shear strength of at least 700 N.

The composite body thus produced constitutes a mounting element and is suitable as an adapter in order to fix the glass ceramic plate to another metal part in or on the oven muffle.

Second embodiment of the production of a cohesive connection according to the invention by means of ultrasonic welding.

In a second embodiment, the brittle material consists of the glass Borofloat 33 ^® with a mean thermal expansion coefficient α _20-300 of 3.3 · 10 ^-6 / K. The surface intended for connection to a metallic shaped body is a fire-polished surface formed in a float process. The intermediate layer of ductile material is an aluminum foil EN-AW-1050A with a thickness of 0.1 mm for use. The metallic molded body consists of a 0.5 mm thick and 22 mm in diameter measuring flat base plate made of the material Kovar with a mean thermal expansion coefficient α _20-300 of 5.5 · 10 ^-6 / K. On the base plate centric and placed perpendicular to her is a firmly connected to the base plate threaded bolt with a height of 12 mm and a diameter of 8 mm for further mounting options according to the further application of the component according to the invention.

In a torsional ultrasonic welding process, the glass Borofloat 33, the intermediate layer of aluminum and the Kovar base plate are welded together using a sonotrode in the form of a hollow cylinder with frontal Rautierung, with the front side of the sonotrode touches the Kovar base plate and a torsional Vibration takes place. The sonotrode amplitude is 25 μm, the sonotrode frequency is 20 kHz, the welding pressure is 2.0 bar and the welding power is 700 Ws.

The composite body thus produced has a surface connection between the Borofloat 33 glass and the intermediate layer of aluminum, on the other hand, and at the same time a connection between the intermediate layer of aluminum and the Kovar base plate. The contact surface produced in the welding process is approximately 1.5 cm ² . A subsequent thermal stress caused by 100 temperature changes between room temperature 25 ° C and maximum temperature 300 ° C, the composite body without visible damage. A test of the resistance of the compound by a mechanical stress test resulted in a shear strength of at least 500 N.

The composite body thus produced constitutes a mounting element and is suitable as an adapter in order to fix the glass ceramic plate to another metal part in or on the oven muffle.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2703736 A1 [0004]
• CA 2183498 [0006]
• DE 3527957 C2 [0007]
• DE 3527958 C2 [0008]
• DE 102008025907 [0009]
• DE 102012204235 A1 [0026]
• DE 19917133 A1 [0028, 0028]

Cited non-patent literature

• EN-AW-1050A [0098]
• EN-AW-1050A [0102]

Claims (11)

Furnace muffle, in particular oven muffle, with at least one at least partially made of glass or glass ceramic wall element which at least partially limits a particular serving as a cooking space, characterized in that the glass or the glass ceramic of the wall element via at least one material connection with at least one component of a metallic material is connected. Furnace muffle according to claim 1, characterized in that the cohesive connection is soldered or welded, in particular ultrasonically welded Furnace muffle according to claim 1 or 2, characterized in that the connection of wall element of glass or glass ceramic and component of metallic material comprises an intermediate layer between the glass or glass ceramic plate and the metallic material, in particular an intermediate layer of a ductile metal. Furnace muffle according to one of claims 1 to 3, characterized in that the material of the wall element of glass or glass ceramic, a low-expansion material in the temperature range 20 ° C to 300 ° C, preferably with a thermal expansion coefficient α (20 ° C - 300 ° C) ≤ 4 × 10 ^-6 / K, in particular ≦ 2 × 10 ^-6 / K, preferably in the range -1.0 × 10 ^-6 / K ≦ α ≦ 4 × 10 ^-6 / K, particularly preferably -0.6 × 10 ^-6 / K ≤ α ≤ 2 · 10 ^-6 / K. Furnace muffle according to one of claims 1 to 4, characterized in that the metallic material of the component has a thermal coefficient of linear expansion α (20 ° C - 300 ° C) ≤ 20 · 10 ^-6 / K, in particular in the range 4 · 10 ^-6 / K ≤ α (20 ° C - 300 ° C) ≤ 6 · 10 ^-6 / K. Furnace muffle according to one of claims 1 to 5, characterized in that the metallic material of the component is tungsten or molybdenum or KOVAR or steel or stainless steel. Furnace muffle according to one of claims 1 to 6, characterized in that it has more than one cohesive, in particular welded, in particular ultrasonically welded connection Furnace muffle according to one of claims 1 to 7, characterized in that it comprises at least two at least partially, preferably made entirely of glass or glass ceramic wall elements and / or that it comprises at least two components made of metallic material Furnace muffle according to claim 8, characterized in that the component or components represent connecting strips. Furnace muffle according to claim 8, characterized in that the component or components represent extract or insertion elements. Furnace muffle according to one of claims 1 to 8, characterized in that the component or the components are mounting elements on the wall or the elements of glass or glass ceramic.

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