Radiant heating device for a cooktop and method for manufacturing a radiant heating device

Abstract

Radiant heating device (15, 115) for a cooktop (11), with: - a flat support (21, 121) made of thermal insulation material with a support top (23, 123), - at least one heating element (27, 127) on the carrier top (23, 123), wherein the heating element (27, 127): - is elongated, - is attached to the top of the carrier (23, 123), - runs in lanes in a pattern and thereby covers a heating surface, - is trained for operation with visible radiation, whereby: - Heat distribution means (33, 133, 233, 333, 433) are arranged in the support (21, 121) below the top of the support (23, 123) and in a surface parallel to the top of the support (23, 123), - the heat distribution means (33, 133, 233, 333, 433) have a minimum distance to the top of the support (23, 123), where the minimum distance is 0.2 mm, - the heat distribution means (33, 133, 233, 333, 433) consist of a heat distribution material whose thermal conductivity is at least 10 W / (m*K), - the heat distribution means (33, 133, 233, 333, 433) span a heat distribution surface and run within this heat distribution surface, - the heat distribution area is at least 70% of the heating area spanned by the at least one heating element (27, 127), characterized in that: - the heat distribution means (33, 133, 233, 333, 433) do not have a completely closed heat distribution surface, - the heat distribution means (33, 133, 233, 333, 433) have interruptions (235, 338) in the heat distribution area they span and - the interruptions (235, 338) form interruption areas, - no heat distribution means or heat distribution material are provided in the interrupted areas.

Description

Area of ​​application and state of the art

[0001] The invention relates to a radiant heating device for a hob and a method for producing such a radiant heating device.

[0002] Such a radiant heating device is known from EP 0 590 315 A2. At least one heating element is arranged on a flat, planar support made of electrically insulating and thermally insulating material. The heating element has a strip shape and is attached to the support in an upright position by being inserted into the top of the support with support feet projecting at regular intervals. Although the individual windings of the heating elements are relatively close together, a gap is nevertheless maintained. During operation of the radiant heating device, the heating elements glow with radiation in the visible range, reaching a temperature of 1,000°C to 1,100°C. This luminous phenomenon makes it possible to see exactly where the heating elements are glowing and thus radiating and generating heat.

[0003] EP 0 627 869 A1 describes a radiant heating device in a cooktop with a flat support made of thermal insulation material. Elongated heating elements are distributed over a surface on the support's upper surface. The thermal insulation material of the support is arranged in two metal sheet shells, which serve to support the support and also distribute its heat. Task and solution

[0004] The invention is based on the object of creating a radiant heating device as mentioned above and a method for its production, with which problems of the prior art can be solved and in particular it is possible to provide a radiant heating device that is as efficient as possible and generates as much heating power as possible or offers the highest possible yield of heating power in comparison to the electrical energy used.

[0005] This object is achieved by a radiant heating device having the features of claim 1 and by a method for its production having the features of claim 13. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are mentioned only for the radiant heating device or only for a method for its production. However, they are intended to be able to apply independently and independently of one another to both a radiant heating device and a method for its production. The wording of the claims is incorporated into the content of the description by express reference.

[0006] The radiant heating device, which is installed alone or advantageously in several units in a cooktop and is arranged beneath a cooktop plate, comprises a flat support made of thermal insulation material which advantageously has a thermal conductivity of less than 1 W / (m*K) at room temperature, particularly advantageously less than 0.5 W / (m*K) or even less than 0.1 W / (m*K). The thermal insulation material can advantageously contain more than 50% fumed silica and materials with a higher refractive index, such as opacifiers. The support is also advantageously substantially flat or planar, at least where it supports at least one heating element on a support top side. This heating element is elongated, in particular strip-shaped, and attached to the support top side. It projects predominantly from the support top side or protrudes above the support top side, i.e. upwards.It runs in paths in a specific pattern, whereby such a pattern can be concentric and / or meandering, for example. The heating element spans a heating surface, which is formed by the surface within the outermost or outermost sections of the heating element. The heating element is designed for operation with visible radiation, whereby a temperature range can extend up to 1,200°C. Advantageously, a temperature range typically goes up to 1,100°C, so that the heating element glows bright orange-red during operation. The heating element is advantageously designed as known from the prior art, for example from the aforementioned EP 590 315 A2. A single heating element can be provided, or alternatively, several heating elements can be provided, for example two or three heating elements. When halogen lamps are used as heating elements, even significantly higher temperatures are possible.

[0007] According to the invention, heat distribution means are arranged in the carrier below the carrier top side, preferably running in a plane parallel to the carrier top side. The heat distribution means are arranged at a minimum distance from the carrier top side, wherein the minimum distance or distance can be 0.2 mm to 3 mm or even up to 10 mm. Thus, the heat distribution means are preferably completely covered by the thermal insulation material, but not too far below the carrier top side or too far away from the heating element, advantageously 0.2 mm to 10 mm. The heat distribution means or a corresponding heat distributor consist of a heat distribution material whose thermal conductivity is greater or significantly greater than that of the thermal insulation material. The thermal conductivity of the heat distribution material is advantageously at least 10 W / (m*K) at room temperature, particularly advantageously at least 20 or 30 W / (m*K).The heat distribution means span a heat distribution surface and run within this heat distribution surface. Similar to what was previously described for the heating surface, the heat distribution surface is formed by the outermost sections of the heat distribution means and encompasses the entire surface therein or in between. This heat distribution surface can be at least 70% of the heating surface spanned by the at least one heating element, advantageously at least 90%. This makes it possible for the heat distribution surface to be located to a significant extent, or to a large extent to a very large extent, where the heating surface is located. This means that the heat distribution surface can very effectively support or supplement the heating surface in terms of its heating effect. At the aforementioned very high temperatures that the heating element reaches during operation and which are at least 800°C, advantageously at least 1.000°C, it was found that a considerable amount of heat energy is radiated upwards by the heating element, as intended and desired. Due to the lateral spacing of the individual turns or tracks of the heating element from one another, certain areas are created in between in which the upper side of the carrier can be seen when viewed from above. However, due to the very low thermal conductivity of the thermal insulation material on this upper side of the carrier, the heat or heating energy is, so to speak, absorbed. This is one of the reasons for using the thermal insulation material for the carrier: to prevent its heat or heating energy from being radiated downwards into the cooktop housing to an excessive extent.

[0008] The purpose of the invention, with the arrangement of the heat distribution means or the heat distributor in the carrier below the top side of the carrier at a short distance from it, i.e. relatively close below the top side of the carrier, is to enable the heat emitted downwards by the heating element to be distributed laterally. This heat is thus conducted laterally and to the side into the areas of the top side of the carrier or the upper area of ​​the carrier where the top side of the carrier lies between two adjacent heating elements. Here, the temperature of the top side of the carrier is already significantly lower than directly below the heating element or in the immediate vicinity of it, in particular at a distance of 1 mm or less. This means that the heat transmitted laterally by the heat distribution means can be emitted upwards again, so that it passes through the thin layer of thermal insulation material above the heat distribution means and can radiate upwards.This occurs predominantly in the areas between two adjacent heating elements. This heat radiates in the same direction as the heating element. This proportion is predictably significantly lower than that of the heating elements themselves, for example, it amounts to only 5% to 20%. Nevertheless, the total heat energy radiated upwards is increased, which improves the upward heating effect of the radiant heating device. Furthermore, less heat is inevitably released downwards into the entire support, or less heat escapes from the support downwards and to the sides, so that the aforementioned effect of heating downwards into a cooktop housing is reduced. The invention thus achieves a twofold advantage.

[0009] In an advantageous embodiment of the invention, the heat distribution means comprise metal or are made entirely of metal. For this purpose, they can preferably comprise iron or steel, as these are good heat conductors, or alternatively aluminum, as this is an even better heat conductor. To prevent corrosion and to achieve long-term stability of the structure, the heat distribution means can comprise stainless steel or be made entirely of stainless steel. A completely corrosion-resistant stainless steel is suitable for this purpose. Other surface quality properties are less important. Aluminum is even better protected by the oxide layer. Other materials such as copper or nickel can also be used. Furthermore, it is entirely possible to use ceramics such as SiC or boron nitride or ceramic fabrics, for example made of SiC fibers or boron nitride, also so-called Tyranno fibers.

[0010] In an embodiment of the invention, the heat distribution means can have a thickness of 0.1 mm to 3 mm, advantageously 1 mm to 2 mm. This thickness is particularly advantageous in the direction perpendicular to the surface of the support's upper side. In other words, the heat distribution means can have a thickness between 0.5% and 15% of the entire support, advantageously between 3% and 10%. Above all, they should be located significantly closer to the support's upper side than to the support's underside, so that thermal insulation downwards is still sufficiently good in all cases.

[0011] The invention provides that the heat distribution means do not have a completely closed heat distribution surface. This means that they themselves are not completely closed or can advantageously have interruptions within themselves and thus in the heat distribution surface. These interruptions in turn form interruption surfaces, and neither the heat distribution means nor heat distribution material are provided in these interruption surfaces. Rather, it is advantageous if thermal insulation material is also provided in the interruption surfaces, primarily in order to achieve stable integrity of the support. In this case, the thermal insulation material passes through the heat distribution means, so to speak. In a further development of the invention, it can be provided that the sum of the interruption surfaces of the heat distribution means is greater than 50% of the total heat distribution surface spanned by the heat distribution means.Under certain circumstances, it may even be possible for the total interrupted areas to exceed 70% of the total heat distribution area spanned by the heat distribution materials. This, in turn, means that the heat distribution material is provided on a maximum of half, preferably a maximum of 30%, of the heat distribution area. Thus, the heat distribution materials only partially interrupt the planar structure of the thermal insulation material, thus ensuring good structural integrity of the carrier and preserving its thermal insulation properties.

[0012] In an advantageous embodiment of the invention, the heat distribution means are designed as a mesh, a grid, a scrim, or a fabric. They can each consist of elongated heat-conducting elements that form the mesh, the grid, the scrim, or the fabric. These elongated heat-conducting elements, for example in the manner of metal wires, can be loosely connected to one another or they can have internal mobility relative to one another. This is particularly possible with the aforementioned embodiments. The advantage here is that expansion due to strong heating, during operation of the radiant heating device at temperatures above 600°C or even above 700°C, does not cause stress in the heat distribution means due to the internal mobility. The individual heat-conducting elements then expand slightly, and the entire heat distribution means spans a somewhat larger heat distribution surface.After cooling, they can also contract again. The aforementioned interrupted surfaces also change their size and arrangement only slightly, so that the structural integrity of the beam is preserved as much as possible. Due to the aforementioned relatively small thickness of the heat-dissipating media, they change only imperceptibly in the thickness direction, especially in the direction perpendicular to the surface of the beam's upper surface. Thus, they do not cause the beam to expand in a damaging way in this direction.

[0013] Preferably, the heat distribution means are designed to be dimensionally stable and / or inherently stable. This makes their handling before manufacturing the entire radiant heating device easier and more practical. Above all, this can also simplify the manufacturing process itself.

[0014] The heat distribution means are particularly preferably designed as a grid with intersecting and elongated heat-conducting elements. These heat-conducting elements can intersect at an angle of approximately 90°. To achieve the aforementioned properties of internal mobility relative to one another on the one hand and dimensional stability on the other, the heat-conducting elements can be positively and / or non-positively connected to one another at contact points, i.e. where two heat-conducting elements touch. However, they should not be materially connected to one another. This allows them to expand to the required extent upon expansion due to strong heating, especially if this may not occur homogeneously. A grid structure is considered very advantageous for this purpose within the scope of the invention, especially because two adjacent heat-conducting elements can each be bent apart in opposite directions.

[0015] Overall, the heat distribution means advantageously runs in a single plane, parallel to the support surface. It is also particularly advantageous to provide one or more heat distribution means in a single plane or layer, rather than distributed across multiple planes within the support.

[0016] Especially for the aforementioned elongated heat-conducting elements, it can be advantageous for their diameter or width to be between 5% and 30% of the distance between two adjacent heat-conducting elements, especially when these heat-conducting elements are directly adjacent to each other. This also makes it possible to achieve the aforementioned goal of the sum of the interrupted areas between the heat-conducting elements being larger or even significantly larger than half of the total heat distribution area spanned by the heat distribution means.

[0017] In a further embodiment of the invention, the carrier material or the carrier can be continuously connected above and below the heat distribution means. This means that the carrier material is connected through the aforementioned interruptions. Thus, the carrier material extends through these interruptions and ensures that the entire carrier is inherently stable, thus maintaining its structural integrity, particularly during operation of the radiant heating device with heating of the heat distribution means and their subsequent expansion.

[0018] A fastening can be provided for the heating element so that it is at least partially embedded in the support or in the support surface. For this purpose, the heating element can particularly advantageously have holding feet at the bottom or on the underside or on the lower edge that project downwards. These holding feet are embedded in the support or in the support surface, in particular pressed or inserted during manufacture of the radiant heating device. This is known from the prior art. If these holding feet can reach close to or very close to the heat distribution means, and if these are made of metal, it is advantageous for the heat distribution means or the holding feet to have an electrically insulating coating, at least on the side facing the heating element. This could, for example, be a glass layer, an enamel layer or ceramic layer, or a lacquer layer that has sufficient temperature resistance.In general, the at least one heating element or its support feet and the heat distribution means can be electrically insulated from one another, preferably by means of an electrically insulating coating.

[0019] Advantageously, the carrier comprises a first layer of thermal insulation material and a second layer of thermal insulation material, which are firmly bonded together. The imaginary separating surface between the two layers runs parallel to the carrier surface. The heat distribution means are arranged between the two layers and are thus firmly embedded in the carrier. At least the layer of the two layers that forms or comprises the carrier's upper surface advantageously has a substantially uniform thickness.

[0020] A method according to the invention for producing a radiant heating device as described above provides that a first layer of thermal insulation material is provided for the support. The thermal insulation material is undisturbed. The heat distribution means are then applied or placed onto this first layer of thermal insulation material. They can be attached, for example, using adhesives or the like, but this is not necessary. Subsequently, a further second layer of thermal insulation material for the support is applied onto the existing first layer and onto the heat distribution means. Undisturbed, partially compressed, or largely or fully compressed thermal insulation material can also be used for the second layer. The thermal insulation material is then pressed again, or the two layers are pressed together, to form the entire support.If both layers have already been partially, largely, or even completely pre-pressed, they should be bonded to one another and to the integrated heat distribution means using a suitable adhesive to ensure the support is stable. The at least one heating element can then be attached to the top side of the support, for example, by inserting it using retaining feet protruding from a lower edge. As previously explained, a further embodiment of the invention can provide for the first layer of thermal insulation material to be not yet fully pressed, in particular unpressed. This allows the applied heat distribution means to sink at least slightly into the loose thermal insulation material, which facilitates pressing the entire support and improves the result.Especially if the second layer of thermal insulation material is applied loosely, i.e. without being partially or completely pressed, the entire support with integrated heat distribution means can be manufactured particularly well and in itself stable.

[0021] In an alternative embodiment of the invention, the first layer of thermal insulation material is at least partially compressed, preferably to at least 30% to 70% of the thickness of the loosely deposited material. The heat-distributing agents are then applied or laid on top. Subsequently, the second layer of thermal insulation material is applied, advantageously pre-compacted to a similar extent as described above for the first layer, or alternatively, uncompacted. The entire support can then be compressed with the heat-distributing agents embedded therein.

[0022] These and other features emerge not only from the claims but also from the description and the drawings. The individual features may be implemented individually or in combination in one embodiment of the invention and in other fields, and may represent advantageous and protectable embodiments for which protection is claimed here. The division of the application into individual sections and subheadings does not limit the generality of the statements made therein. Brief description of the drawings

[0023] Embodiments of the invention are illustrated in the drawings and explained in more detail below. In the drawings: Fig. 1 a section through a hob according to the invention with a radiant heating device according to the invention, Fig. 2 a plan view of the radiant heating device from Fig. 1, Fig. 3 an alternative design of a radiant heating device with a differently designed support, Fig. 4 a plan view of a first embodiment of a heat distributor according to the invention with slots in a thin plate, Fig. 5 a plan view of an alternatively designed heat distributor as a grid of wires running at right angles to each other, Fig. 6 a sectional view through the grid of the heat distributor from Fig. 5 and Fig. 7 a sectional view similar Fig. 6 by a heat distributor in the form of a grid made of flat wires. Detailed description of the implementation examples

[0024] In the Fig. Figure 1 shows a sectional view through part of a hob 11. The hob 11 has a hob plate 12 with a bottom 13. A radiant heating device 15 according to the invention is pressed onto this bottom 13. Advantageously, additional heating devices or radiant heating devices of the same type and design are located beneath the hob plate 12 of the hob 11.

[0025] The radiant heating device 15 comprises a sheet metal shell 17 with a base and raised edge, in which an insulating edge 19 is located on a support 21. The insulating edge 19 and support 21 are each made of a thermally insulating material described above, preferably fiber-free. Its thermal conductivity can be less than 1 W / (m*k). The two parts are pressed against each other, and the insulating edge 19, in particular, has a sufficiently high strength so that the radiant heating device 15 can be pressed from below against the underside 13 of the cooktop plate 12.

[0026] The carrier 21 is designed as a type of thick disc with a largely or substantially flat carrier upper side 23. Parallel to this runs a carrier lower side 24, with which the carrier 21 rests on the bottom of the sheet metal shell 17.

[0027] On the upper side 23 of the carrier, an elongated heating element 27, as described above, is arranged, which is band-shaped with a thickness of approximately 0.05 mm and a height of, for example, 3 mm. The course of the heating element 27 on the carrier 21 can be seen from the top view of the Fig. 2; in particular, it is a kind of mixture of concentric and meandering. The heating element 27 protrudes outward through the insulating edge 19 with connection ends 30a and 30b to allow electrical contact. This is a design known in the prior art.

[0028] According to the invention, a flat and planar heat distributor 33 is arranged within the carrier 21 as the previously described heat distribution means. In the sectional view of the Fig. 1 shows that the heat distributor 33 is considerably closer to the support top surface 23 than to the support bottom surface 24. For example, if the thickness of the support 21 is approximately 12 mm to 15 mm, the distance between the heat distributor 33 and the support top surface 23 can be approximately 2 mm to 3 mm, but in principle also less, theoretically even up to 0.2 mm. The thickness of the thermal insulation material of the support 21 above the heat distributor 33 is thus considerably less than the thickness below, for example by a factor of 3 to 10.

[0029] Furthermore, it can be seen that the heat distributor 33, viewed in the horizontal direction, even protrudes slightly below the heating element 27 or projects outwards beyond it. This is also evident from the dashed line in the top view of the Fig. 2. In particular, the heat distributor 33 can extend almost under the entire support surface 23, which is exposed within the insulating edge 19. Thus, heat that the heat distributor 33 has absorbed from the heating element 27 within the support 21 can be distributed across the surface, i.e., in a horizontal direction, and then radiated upwards again toward the cooktop plate 12. Below the thick insulating edge 19, this would clearly no longer make sense.

[0030] From the top view of the Fig. 2 clearly and easily shows that the flat design of the heat distributor 33 below the heating element 27, which runs along its paths, means that there is a large area, in particular more than 70% or even more than 80%, of the surface of the support top 23 above the heat distributor 33 not directly covered by the heating element 27 and is thus shielded. This very effectively achieves the effect mentioned above, namely that heat emitted downwards into the support 21 by the heating element 27 is absorbed by the heat distributor 33 arranged just below it. This heat is emitted downwards by the heating element 27 anyway. The heat is then distributed horizontally by the heat distributor 33, in particular across its entire surface and approximately evenly, and then emitted upwards again.This heat must pass through the thin layer of thermal insulation material above it again, but due to its thinness, this is easily possible. The heat is distributed primarily in the material of the heat distributor 33 itself and not in the thermal insulation material of the support 21. Of course, the heat is only dissipated upwards where a part of the heating element 27 does not run directly above it. According to the top view of the . Fig. 2, however, sufficient small surfaces remain, for example, between two adjacent heating elements or tracks of the heating element 27, so that the heat distributor 33 can release or radiate heat upwards between them. This achieves the effect explained above, namely that more heat is released or radiated upwards overall. Furthermore, this heat is then also not released downwards into the support 21 and the cooking surface 11. This is a further advantage of the invention.

[0031] In the Fig. Figure 3 shows how, in a radiant heating device 115, a support 121 is not formed as a single piece with the heat distributor 133 integrated therein, but rather consists of an upper part 122a and a lower part 122b. A clear separation can be seen between these two, and the heat distributor 133 runs exactly between them. Either the upper part 122a and the lower part 122b can be manufactured as semi-finished products, i.e., also pressed together, and then, with the heat distributor 133 in between, inserted into a sheet metal shell corresponding to Fig. 1, or they can be pre-glued with the heat distributor 133 in between. Alternatively, they can be prefabricated with only partial compression and then finally pressed together with the heat distributor 133 between them, so that they are already stably connected to each other as a separate part. As yet another alternative, they can be pressed from loose bulk material with the heat distributor 133 inserted, thereby maximizing integral strength. This was also explained at the beginning.

[0032] From the Fig. 3 it can also be seen that in the heating element 127 shown here, holding feet 128 project downwards and are fully inserted into the carrier 121 or into the upper part 122. The length of the holding feet 128 can be approximately as long as the height of the heating element 127 itself, but can advantageously be somewhat shorter, for example, approximately 2 mm to 3 mm. It is advantageous if the holding feet 128 do not touch the heat distributor 133, although the distance could and should be small. The heat distributor 133 is advantageously made of the metal mentioned above, in particular aluminum or stainless steel, each with a high known thermal conductivity of approximately 200 W / (m*K) or 20 W / (m*K). Direct contact with the holding feet 128 could, however, lead to undesired current flow and, in particular, to a short circuit. This could generally be remedied by the heat distribution medium orThe heat spreader 133 is coated with an electrically conductive coating of any desired type, which can be, for example, an oxide layer, or alternatively, an enamel or glass layer. However, it would be better in any case to arrange the heat spreader 133 at a small distance below the support feet 128. The distance can advantageously be at least 0.1 mm or 0.2 mm, but should not exceed 2 mm or even 3 mm.

[0033] In the Fig. Figure 4 shows a plan view of a first embodiment of a heat distributor 233 according to the invention. The heat distributor 233 consists of a thin metal plate 234 with a thickness of approximately 0.2 mm, preferably made of aluminum or stainless steel. Radially extending slots 235 are introduced, in particular punched, into the metal plate 234, only a few of which are shown here. A central region remains in the middle of the holding plate 234 to ensure the stability of the heat distributor 233. The radially extending slots 235 enable good heat distribution in the radial direction. Furthermore, an attempt can be made to compensate for expansion of the heat distributor 233 during heating during operation of a radiant heating device in which it is installed. It should also be noted that the radially extending widening regions of the plate 234 do not necessarily have to be continuous in the radial direction.Heat conduction in the heat distributor is generally not required over long distances for the function of the invention; in fact, good heat conduction over a distance corresponding to the distance between two tracks of the heating element 27 is sufficient. Fig. 2 corresponds.

[0034] An alternative and preferred embodiment for a heat distributor 333 is the Fig. 5. The heat distributor 333 is designed here as a grid with vertical wires 337a and horizontal wires 337b; they can be made of stainless steel or aluminum. As previously described, they can also be electrically insulated on the surface or at least on the top, for example with a glass, ceramic, or enamel layer. Advantageously, the wires 337a and 337b are identical and designed as round wires with a thickness of approximately 1 mm. The distance between directly adjacent wires can be 3 mm or more. The grid of the heat distributor 333 is visibly regularly designed; the wires 337a and 337b intersect at right angles with spaces 338 in between that correspond to the aforementioned interruptions. These wires 337a and 337b are not permanently connected to one another, welded or glued. They are only, as the Fig. 6 shows in section, each bent into a very slight zigzag shape. This makes the heat spreader 333 relatively stable. For example, it can be manufactured as a very large mat and cut or punched out of it in the appropriate size. Furthermore, individual wires 337a and 337b can move relatively easily in terms of their length and also in their position relative to each other due to thermally induced expansion. This is the case with the metal plate of the Fig. 4 hardly or not at all possible.

[0035] The sectional view through the heat distributor 333 according to Fig. Figure 6 corresponds to a typical design of such a grid. The distance between the round wires 337a on the one hand and the round wires 337b on the other hand is exaggerated here for clarity. Typically, they are adjacent to each other.

[0036] In the Fig. 7 is a sectional view through a further heat distributor 433 according to the invention, which is similar to Fig. 6. Here, however, the grid is formed from flat wires 439a and 439b, as can be clearly seen in the section through the flat wire 439a. This allows the area of ​​the gaps 338 in the grid of the heat distributor 333 to be Fig. 5 can be reduced again slightly so that the total area of ​​all gaps is at least 50% of the total area of ​​the heat distributor 333.

Claims

[1] Radiant heating device (15, 115) for a cooking hob (11), comprising: - a flat support (21, 121) made of thermal insulation material with a support top side (23, 123), - at least one heating element (27, 127) on the carrier top side (23, 123), wherein the heating element (27, 127): - is elongated, - is attached to the top of the support (23, 123), - runs in a pattern and creates a heating surface, - designed for operation with visible radiation, where: - heat distribution means (33, 133, 233, 333, 433) are arranged in the carrier (21, 121) below the carrier top side (23, 123) and in a surface parallel to the carrier top side (23, 123), - the heat distribution means (33, 133, 233, 333, 433) have a minimum distance from the carrier top (23, 123), the minimum distance being 0.2 mm, - the heat distribution means (33, 133, 233, 333, 433) consist of a heat distribution material whose thermal conductivity is at least 10 W / (m*K), - the heat distribution means (33, 133, 233, 333, 433) span a heat distribution surface and run in this heat distribution surface, - the heat distribution area is at least 70% of the heating area spanned by the at least one heating element (27, 127), characterized by , that: - the heat distribution means (33, 133, 233, 333, 433) do not have a completely closed heat distribution surface, - the heat distribution means (33, 133, 233, 333, 433) have interruptions (235, 338) in the heat distribution surface spanned by them and - the interruptions (235, 338) form interruption surfaces, - no heat distribution means or heat distribution material are provided in the interruption areas. [2] Radiant heating device according to claim 1, characterized bythat the heat distribution means (33, 133, 233, 333, 433) comprise metal or consist entirely of metal. [3] Radiant heating device according to claim 1, characterized by that the heat distribution means (33, 133, 233, 333, 433) comprise ceramic or consist entirely of ceramic. [4] Radiant heating device according to one of the preceding claims, characterized by that the heat distribution means (33, 133, 233, 333, 433) have a thickness of 0.1 mm to 3 mm. [5] Radiant heating device according to one of the preceding claims, characterized by that the sum of the interrupted areas is greater than 50% of the total heat distribution area spanned by the heat distribution means (33, 133, 233, 333, 433). [6] Radiant heating device according to one of the preceding claims, characterized byin that the heat distribution means (333, 433) are a mesh, a grid, a scrim or a fabric consisting of elongate heat-conducting elements (337a, 337b, 437a, 437b) which are loosely connected to one another and / or which have an internal mobility relative to one another, wherein the heat distribution means (333, 433) are inherently dimensionally stable and / or intrinsically stable. [7] Radiant heating device according to claim 6, characterized by that the heat distribution means (333, 433) are designed as a grid with intersecting elongated heat conducting elements (337a, 337b, 437a, 437b), wherein the heat conducting elements (337a, 337b, 437a, 437b) are connected to one another at contact points in a form-fitting and / or force-fitting manner, but not in a material-fitting manner. [8] Radiant heating device according to claim 6 or 7, characterized bythat a diameter or a width of the heat conducting elements (337a, 337b, 437a, 437b) is between 5% and 30% of the distance between two adjacent heat conducting elements (337a, 337b, 437a, 437b). [9] Radiant heating device according to one of the preceding claims, characterized by that the carrier material and the carrier (21, 121) are continuously connected to one another above the heat distribution means (33, 133, 233, 333, 433) and below the heat distribution means (33, 133, 233, 333, 433), wherein carrier material runs through the interruptions (235, 338) in the heat distribution means (33, 133, 233, 333, 433). [10] Radiant heating device according to one of the preceding claims, characterized by that the at least one heating element (27, 127) is at least partially embedded in the carrier (21, 121) and in the carrier surface for fastening. [11] Radiant heating device according to claim 10, characterized bythat the at least one heating element (27, 127) and / or its holding feet (128) and the heat distribution means (33, 133, 233, 333, 433) are electrically insulated from one another by means of an electrically insulating coating, wherein an electrically insulating coating is applied to the heat distribution means (33, 133, 233, 333, 433). [12] Radiant heating device according to one of the preceding claims, characterized by that the carrier (121) has a first layer (121a) of thermal insulation material and a second layer (121b) of thermal insulation material, which are firmly connected to one another and between which the heat distribution means (33, 133, 233, 333, 433) are arranged. [13] A method for producing a radiant heating device according to any one of the preceding claims, wherein - a first layer (121a) of thermal insulation material is provided for the carrier (121), - the heat distribution means (133) are applied or placed on the first layer (121a) of thermal insulation material, - then a further 2nd layer (121b) of thermal insulation material for the support (121) is applied to the other 1st layer (121a) and the heat distribution means (133), thereafter, the thermal insulation material is pressed to form the support (121), after which the heating element (27, 127) is attached to the support top (123), characterized by that the heat distribution means (133) are applied or placed on an unpressed first layer (121a) of thermal insulation material. [14] Method according to claim 13, characterized by that the second layer (121b) of thermal insulation material is applied to the heat distribution means (133) without pressing, and then the entire composite of thermal insulation material with the heat distribution means (133) embedded therein is pressed. [15] Method according to claim 13, characterized by , that - first the 1st layer (121a) of thermal insulation material is at least partially pressed, - the heat distribution means (133) are then applied or laid on, whereby thermal insulation material for the second layer (121b) is then applied uncompacted or pre-compacted to the heat distribution means (133), - subsequently, a final pressing of the carrier (121) with heat distribution means (133) embedded therein takes place.

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