Method for operating a radiant heating device, radiant heating device, and hob having a radiant heating device
The radiant heating device uses an edge-mounted temperature sensor and empirical data to calculate critical point temperatures, enhancing accuracy and safety through indirect measurement.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- E G O ELEKTRO GERAETEBAU GMBH
- Filing Date
- 2025-09-29
- Publication Date
- 2026-05-15
AI Technical Summary
Existing radiant heating devices struggle with accurate and practical temperature measurement, particularly at critical points where sensors are not directly installed, leading to inefficiencies in temperature control and safety monitoring.
A radiant heating device with a temperature sensor positioned in the edge region and a control unit that uses stored empirical data to calculate temperatures at critical points based on operating mode, duration, and power output, combined with a reference sensor for non-contact measurement.
Enables precise temperature determination at critical points without direct installation, improving temperature control and safety monitoring through accurate and efficient temperature calculation.
Smart Images
Figure EP2025077830_15052026_PF_FP_ABST
Abstract
Description
[0001] Method for operating a radiant heating device, radiant heating device and cooktop with a radiant heating device
[0002] Application area and state of the art
[0003] The invention relates to a method for operating a radiant heating device and a radiant heating device designed for carrying out this method, as well as a cooktop equipped with at least one such radiant heating device. The radiant heating device comprises at least one heating element on a support and at least one temperature sensor in the edge region of this support.
[0004] From DE 10 2022 204 359 A1, a radiant heating device for a cooktop is known, in which the temperature is measured by means of a temperature sensor in the center of the support. An elongated heating element is laid flat and in strips on the support. The temperature sensor can measure the temperature in the central area of this radiant heating device.
[0005] Task and solution
[0006] The invention is based on the objective of creating a method mentioned above, a radiant heating device designed for its implementation and a cooktop equipped therewith, with which problems of the prior art can be solved and it is particularly possible to measure a temperature at the radiant heating device simply, accurately and practically with a simple and practical design of the radiant heating device.
[0007] This problem is solved by a method with the features of claim 1, by a radiant heating device with the features of claim 6, and by a cooktop with the features of claim 15. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. Some of the features are described only for the method, only for the radiant heating device itself, or only for a cooktop equipped with it. However, they should be applicable independently and separately to such a radiant heating device, to a method for operating it, and to a cooktop equipped with at least one such radiant heating device.
[0008] The radiant heating device has a flat, planar support with an edge region. This edge region lies within the outer 70% to 99% of the support's diameter or width. In other words, the edge region lies within the outer 30% of the support. The radiant heating device has at least one long or elongated heating element that runs along the support in a path and is attached to it. The heating element runs within a planar heating area, or rather, its path defines the heating area; that is, the heating area is where a heating element is present and where very high temperatures occur. Advantageously, the shape of the heating area corresponds to the shape of the support or the radiant heating device, and is particularly advantageous if it is round or circular.
[0009] At least one temperature sensor is provided in the perimeter area, which is connected to a control unit for the power supply of the radiant heating device. This control unit is advantageously a microcontroller or the like. The power supply of the radiant heating device can include switching elements such as relays or semiconductor switches suitable for practical operation of the radiant heating device. Typical radiant heating devices like the one mentioned above can be controlled or powered by relays. Preferably, an additional temperature sensor, in particular an NTC thermistor, is provided on the control side for continuous reference measurement of the temperature sensor in the radiant heating device. This additional temperature sensor for continuous reference measurement can be arranged on a circuit board of the control unit, as is known to those skilled in the art.
[0010] The procedure is carried out in the following steps, although further steps may be added, even in between. Generally, it is intended that during the operation of the radiant heating device or an electrical appliance in which the radiant heating device is installed, for example, a cooktop, the temperature sensor records the temperature so that it is available to the connected control unit and can be processed or used. In this way, the control unit always knows the temperature at and recorded by the temperature sensor. It can be measured continuously or at specific time intervals, which should not exceed 5 or even 1 second. The control unit connected to the power supply receives operating information from it about the operating mode and / or the operating duration of the radiant heating device, or about its operation.This can and should advantageously be linked to information about which heating element of this radiant heating device is being operated, in particular whether all heating elements of this radiant heating device are being operated. Furthermore, the control unit receives information from the power supply about the power level at which the radiant heating device, or at least one heating element (advantageously all heating elements of this radiant heating device), is being operated and has been operated up to that point. This power level can also be directly related to the operating mode and / or operating duration; in this case, the information is essentially equivalent.
[0011] The control unit stores memory values for various temperatures at the radiant heating element. These temperatures depend on the operating mode and / or duration, as well as the power output of the radiant heating element or heating component. These temperatures apply to a different defined point than the location of the temperature sensor. These stored values are used to determine the temperature at a specific point on the radiant heating element, based on both the temperature measured at the temperature sensor and the stored values.Based on the temperature determined at a specific point on the radiant heating device, a function can be triggered to control the device. This function is selected from the following group: warm or hot indicator for the radiant heating device; power reduction for at least one heating element or for the entire radiant heating device due to reaching the maximum temperature; temperature-controlled operation of the radiant heating device or heating element. Additional options may be added to this list; it is not exhaustive.
[0012] The principle of the invention can also be expressed simply as follows: a temperature is measured at a different point on the radiant heating device than the defined point where the temperature is relevant or required. The measured temperature can then be corrected, so to speak, based on information about the operating mode and duration, as well as the heating output generated so far. In this way, the temperature at the defined point of interest can be calculated from older or recorded and stored empirical data, based on operating duration, operating mode, and / or power output.
[0013] Thus, the invention makes it possible to measure the temperature at a point during the operation of a radiant heating device. While this point is not the relevant, of interest, or critical point, it is nevertheless a point or area where measurement is relatively easy and requires minimal effort. By calculating or determining the temperature at a specific point or area of interest, based on the stored values and taking into account the previous operating mode and / or duration of the radiant heating device, which are decisive for the temperatures at that point, a temperature can then be obtained. Generally, the stored values in the control unit can be obtained as follows: In a preliminary step, the aforementioned radiant heating device is equipped with a reference temperature sensor at a defined point.Advantageously, this is a point located above the heating element, or where a maximum temperature prevails above the radiant heating device or heating element and below the cooktop. This radiant heating device is then installed in a cooktop of a defined type in the same way as it will be in subsequent series production. This precisely replicates how the radiant heating device will be installed in a cooktop during later operation, ensuring the same temperature conditions and other properties. The point where the cooktop temperature is measured by the reference temperature sensor can be located in a central area of the radiant heating device. Advantageously, this temperature is measured using a pyrometer or an IR / thermal imaging camera as a reference temperature sensor, particularly from above, thus providing a non-contact and therefore accurate measurement.Very accurate and reliable temperature measurement is possible. Alternatively, a reference temperature sensor similar to the temperature sensor used for measurements during operation can be used; this sensor is then installed in the radiant heating device for the reference measurements.
[0014] The radiant heating device is then operated in a variety of different operating modes and / or for varying durations. It is also operated at different power levels, for example, at very high or maximum continuous power, as well as at medium and low power. Preferably, the radiant heating device is operated intermittently, so that the heating element, or at least one heating element, is either operating at full power or is switched off. This results in an average power level over time. Such intermittent operation of a radiant heating device is known in the art and is even common practice. This corresponds to a type of pulse-width modulation, whereby the radiant heating device, or at least one heating element, should not typically be switched on and off too frequently per minute.The switching frequency of the radiant heating device can depend on the power at which it is operated, ranging from 2 to 20 times per minute. During the aforementioned varying operation of the radiant heating device, or of at least one heating element of the radiant heating device, the temperature is continuously measured at both the temperature sensor and the reference temperature sensor. These measured temperatures are stored. Either during the initial storage or later in the memory, these measured temperatures are stored together, or they are combined depending on the different operating mode, duration, and / or power level.This allows for consideration of the fact that, for example, during very rapid heating of the radiant heating device at maximum power, the difference between the temperature at the temperature sensor and the temperature at the reference temperature sensor is greater than after, say, twenty minutes. This can be due to dynamic processes, particularly the radiant heating device heating up from a cool state. A corresponding temperature difference may also be smaller at the beginning of heating or during operation of the radiant heating device if heating occurs at only medium or even low power. This embodiment of the invention thus allows the stored values to be obtained in a way that closely reflects real-world conditions.
[0015] Subsequently, these acquired storage values can be stored in the control units of a mass-produced cooktop of the same type. If this type of cooktop has, for example, four radiant heating elements, the storage values for all four radiant heating elements are preferably acquired separately, at least if they are of different designs and / or sizes.
[0016] The aforementioned method of obtaining the stored values allows the respective temperature at a defined point of the radiant heating device to be precisely determined, i.e., not by approximate calculation based on different theoretical assumptions that do not necessarily apply in practice, but based on actual measurements.
[0017] In a possible further development of the invention, it may be provided that the stored values are available in the form of several or a multitude of tables, which are ordered according to operating type, operating duration and / or power level.
[0018] In another embodiment of the invention, correction values can be calculated or derived from the stored values, depending on a few factors.
[0019] In a further development of the invention, the radiant heating device can be provided with more than just a single independently operable heating element, advantageously two or three heating elements. In this case, only a single temperature sensor is still advantageously attached to the radiant heating device. When obtaining the aforementioned stored values, it should be taken into account that, as a sub-type of operating mode, operation in different combinations of the at least two heating elements, and thus of all heating elements of this radiant heating device, must also be considered. Finally, the temperature conditions in or on the radiant heating device are significantly affected if additional heating elements are operated or heated. In practice, it can advantageously be assumed that these additional heating elements are operated in the same way, in particular with the same pulse frequency or with different pulse frequencies.Therefore, their performance level is essentially the same or predictable.
[0020] In a possible further development of the invention, it can be provided that a sudden change in the specific temperature at the defined point, in particular by at least ± 10°C per second, is determined by placing a pot on a cooking zone heated by the radiant heating device or by removing a pot from this cooking zone. Due to the very precise determination of the temperature possible according to the invention, even relatively small fluctuations can be assigned a precisely defined significance.
[0021] In a further possible embodiment of the invention, a hot indicator for a cooking zone heated by the radiant heating element on a cooktop can be activated as soon as the temperature at any point on a cooktop surface above the radiant heating element, where the cooking zone is located, exceeds a defined temperature, such as 50°C, or alternatively, a general temperature between 40°C and 200°C. Advantageously, this temperature is taken at the defined point, as this point is advantageously defined such that it most frequently, or always, exhibits the highest temperature on the radiant heating element or under the cooktop surface.
[0022] In an advantageous embodiment of the invention, the temperature sensor is a thermocouple. This has the significant advantage of being highly temperature-resistant and also very robust in handling and installation, both on the radiant heating device itself and on a cooktop. The use of such thermocouples is known to those skilled in the art and can be implemented easily and without problems.
[0023] Preferably, a metal plate can be arranged on the aforementioned thermocouple, or a conventional welded connection of the thermocouple can be abutted or welded to a metal plate. Preferably, this metal plate can have a relatively small area, for example, less than 12 mm x 12 mm, and in particular less than 8 mm x 8 mm. The thickness of the metal plate can be from 0.1 mm to a maximum of 3 mm, or even as little as 1 mm. The metal plate facilitates the mechanical fixing of the thermocouple.
[0024] In a preferred embodiment, the temperature sensor is arranged at the end of an elongated support structure, and it should be electrically insulated from the support structure. For this purpose, the elongated support structure can preferably be made of ceramic or at least partially, and in particular entirely, of ceramic. The two electrical connections for the temperature sensor, especially if they are the two connecting wires for a thermocouple, can advantageously be routed within the support structure. This protects them mechanically from damage during installation on the radiant heating device and thermally from high operating temperatures.
[0025] In a further possible embodiment of the invention, the elongated support structure with the temperature sensor at its tip can project inwards over one side or edge of the support for the at least one heating element. An outer edge section, advantageously designed in the form of a ring, can be placed on the support. The support structure can project through or pass through this outer edge section. Outside the outer edge section, the support structure can be attached to a connection housing, which can be designed essentially as is known for radiant heating devices. Thus, the connection housing has electrical connections, advantageously at least to the temperature sensor and particularly advantageously also to the at least one heating element or even to all heating elements of this radiant heating device.The connection housing can be attached to the support, advantageously to a mounting bracket for the support, which is preferably made of metal or thin sheet metal. This allows for the creation of a single unit consisting of the connection housing and the temperature sensor, or of a mounting bracket for the temperature sensor. This unit simply needs to be positioned appropriately against the radiant heating device and then attached to it. Electrical contacts can protrude inwards, to which the heating elements are electrically connected. This is known from the prior art for so-called rod controllers for radiant heating devices, which also serve, to a certain extent, to detect temperatures at the radiant heating device or at least to detect when these temperatures exceed or fall below certain defined levels.Alternatively, the temperature sensor and its mounting bracket can simply be inserted through the outer edge section, thus eliminating the need for the aforementioned connection housing. The connecting wires for the thermocouple can then protrude from the mounting bracket and be connected to a control unit, for example, via plug connectors or similar.
[0026] In an advantageous embodiment of the invention, the temperature sensor can extend outside the heating area or over a region of the carrier that is free of any heating elements or in which no heating element is provided. This can apply to the perpendicular or vertical projection of the temperature sensor onto the carrier; advantageously, this projection can also have twice or even three times the area. However, it should not exceed this, since the space on the carrier or its surface should be occupied as much as possible by the at least one heating element.These and other features are evident not only from the claims but also from the description and the drawings, whereby the individual features, either alone or in combination, may be implemented in one embodiment of the invention and in other fields, and may represent advantageous and individually protectable embodiments for which protection is claimed here. The division of the application into individual sections and subheadings does not limit the general validity of the statements made therein.
[0027] Brief description of the drawings
[0028] Exemplary embodiments of the invention are shown schematically in the drawings and are explained in more detail below. The drawings show:
[0029] Fig. 1 shows an oblique view of a radiant heating device according to the invention with a temperature sensor according to the invention and a single heating element,
[0030] Fig. 2 is a top view of the radiant heating device from Fig. 2 with an indicated lower reference temperature sensor in a free central area,
[0031] Fig. 3 shows a top view similar to Fig. 2 of another radiant heating device according to the invention with two heating elements, and
[0032] Fig. 4 shows a sectional view of an arrangement of the radiant heating device from Fig. 1 and 2 in a cooktop according to the invention, including a reference temperature sensor and alternatively a pyrometer for detecting and recording various temperature values.
[0033] Detailed description of the exemplary implementations
[0034] Figure 1 shows an oblique view and Figure 2 shows a top view of a radiant heating device 11 according to the invention, as known, for example, from the aforementioned DE 10 2022 204 359 A1. Reference is also made to this document. The radiant heating device 11 has a planar and flat support 13 with a central region 14, on the upper surface of which an edge body 16 is mounted in the edge region. This design can also be seen in the sectional view of Figure 4. The support 13 and the edge body 16 are made of a conventional material known and widely used for radiant heating devices.
[0035] The support 13 with the edge body 16 on it is placed in and secured within a plate-shaped receiving tray 18. The receiving tray 18 can be made of thin sheet metal, as is customary. An elongated heating element 20 is laid on the upper side of the support 13 in a meandering pattern and in concentric bands; this laying pattern is known from the prior art. A narrow, strip-like free area 15 extends from the free central area 14 to the edge body 16. No part of the heating element 20, or indeed no heating element 20 itself, is visibly located within this free area 15.
[0036] Near the edge of the support 13, a temperature sensor 22 is arranged above the clearance 15. Advantageously, it consists of a thermocouple mounted on a rectangular or square metal plate. Advantageously, the two contact wires of the thermocouple, with their conventional design, are welded to the metal plate. This is also known in principle from the prior art. The temperature sensor 22, or the aforementioned metal plate, is arranged and attached at the front end of an elongated ceramic tube 24. This ceramic tube 24 extends inwards through a corresponding opening in the edge body 16 and runs horizontally and radially. Thus, it itself extends above the clearance 15. The connecting wires, and therefore an electrical connection for the temperature sensor 22, run inside the ceramic tube.Outside the outer body 16, the ceramic tube 24 is attached to a connection housing 26, as is generally known from the prior art. Electrical connection options, in particular plug connectors or plug connector tabs, typically protrude from the connection housing 26. This is generally known from the prior art and is indicated in particular by a connecting cable 27 as shown in Fig. 4. The heating element 20 is also connected to the connection housing 26 and the plug connector tabs therein in a known manner by means of electrical connections 21. Thus, the entire electrical connection to the radiant heating device 11 is made via the connection housing 26.
[0037] In the top view of Fig. 2, a reference temperature sensor 28 is shown in dashed lines in the central area 14, advantageously located exactly in the center of the support 13. It is arranged, for example according to the aforementioned DE 10 2022 204 359 A1, on a sensor holder 29 and mounted on top of it. Alternatively, instead of such a reference temperature sensor, a pyrometer can also be used to measure from above, which will be explained further below with reference to Fig. 4.
[0038] Figure 3 shows a further embodiment of a radiant heating device 111. Similar to the radiant heating device 11 shown in Figures 1 and 2, it has a round and flat support 13, advantageously with a larger diameter than shown in Figures 1 and 2. The support 113 has a free central area 114. An annular edge body 116 is attached to its outermost edge. Together with this, the support 113 is inserted into and secured in a plate-like receiving tray 118. Two heating elements 120a and 120b run along the top surface of the support 113, in principle with a similar arrangement pattern as in Figure 2. However, heating element 120a runs in the outer diameter region of the support 113, and the other heating element 120b runs in the inner diameter region. The heating elements 120a and 120b are connected to a receiving housing 126 by means of three electrical connections 121, including plug-in terminals or the like provided therein.
[0039] In the edge region near the edge body 116, a temperature sensor 122 is arranged at the end of a ceramic tube 124, similar to the arrangement shown in Fig. 1, but without a free area below or above the heating element 120a. The temperature sensor 122 is advantageously designed as described above, i.e., as a thermocouple. Its connecting wires run inside the ceramic tube 124 to the connection housing 126, where they are connected to protruding plug-in terminals.
[0040] Thus, the radiant heating device 111 of Fig. 3 shows a dual-circuit radiant heating device, or a so-called dual-circuit heater. The two heating elements 120a and 120b can be operated together for large pots, or only the inner heating element 120b can be operated for small pots. A single temperature sensor 122 is sufficient here as well to accurately determine temperatures. For this, the operating mode must be known, i.e., whether only the heating element 120b is operated or both heating elements.
[0041] Figure 4 shows a partial view of a cooktop 1, as is generally known. The cooktop 1 has a conventional cooktop plate 3, under which, or pressed against its underside, a radiant heating element 11 according to Figures 1 and 2 is arranged. In this case, the aforementioned reference temperature sensor 28 is actually temporarily present and attached to a corresponding sensor holder 29. It is connected to a control unit 31 by means of a cable 30. As an alternative to the reference temperature sensor 28 within the radiant heating element 11 for measuring the temperatures, the pyrometer 28' can be arranged above the central area of the radiant heating element 11. The pyrometer 28' has the significant advantage that it allows for non-invasive temperature measurement of the cooktop plate 3.No effort is required for the installation and electrical connection of the reference temperature sensor 28 in the radiant heating device 11; a pyrometer can easily be installed above it.
[0042] The temperature sensor 22 is also connected to the control unit 31 via the aforementioned connecting cable 27. Likewise, the heating element 20 is connected to a power supply 33 via a cable 32 and is supplied with power in a known manner not shown here. The power supply 33 can include switches, for example, power relays. Likewise, known semiconductor switches or the like can be used.
[0043] The radiant heating element 11 and the cooktop 1 are designed and arranged exactly as they will later be in series production. It may even be possible for the radiant heating element 11 to be arranged in precisely the same position in the cooktop 1 as this exact type of radiant heating element will be arranged in this exact type of series-produced cooktop.
[0044] A control unit 31, configured as a reference, executes various operating modes at the heating element 20 via the power supply 33. This involves different operating durations combined with different power levels or outputs over a specific period. The temperature is measured at the reference temperature sensor 28 or the pyrometer 28' and evaluated and recorded by the control unit 31. Simultaneously, the corresponding temperatures are measured and recorded by the temperature sensor 22. In particular, the two temperatures are correlated and stored. This can be organized according to different operating modes and / or operating durations, so that the respective correlated temperatures are stored for a large number of different operating modes and durations.Thus, later in the operation of a series-produced cooktop 1 with series-produced radiant heating devices 11, under known conditions for operating type and operating duration, the correct temperature in the central area 14 of the radiant heating device 11 can be determined from the correlated pair of values of the temperature recorded at the temperature sensor 22, in particular at the cooktop plate 3, i.e. where it is of interest, but where there is no temperature sensor.
[0045] The temperatures, values, or pairs of values recorded by the controller 31 during the aforementioned operation are then advantageously processed, particularly with regard to the correlation of the temperatures at the reference temperature sensor 28 or the pyrometer 28' on the one hand and at the temperature sensor 22 on the other, and possibly also compressed to reduce the amount of storage space required. This data is then programmed into each controller that is installed in the series production of the radiant heating device 11 for a corresponding cooktop 1. Thus, during actual operation of the series-produced cooktop, the temperature of the radiant heating device 11 can be adjusted based on a temperature recorded by the temperature sensor 22, taking into account previous operating conditions, in particular the operating mode and duration.The temperature of the heating element 20 can be determined by reading the corresponding correlated temperature, which is the temperature prevailing in the central area 14 at the location of the reference temperature sensor 28. In this way, the temperature at this point above the central area 14, which typically has the highest temperatures during operation of the standard cooktop, can be determined without actually having a temperature sensor at that point.
[0046] The arrangement of the temperature sensor 22 so close to the edge of the support 13, or rather close to the edge body 16, offers the significant advantage that the design, particularly of a holder or similar component for the temperature sensor 22 itself, is much simpler. Compared to known rod controllers that thermomechanically determine temperature, the design is simpler. Furthermore, not only can individual temperature points or temperature ranges be determined, but any temperature within a wide range can be measured with relative accuracy. Additionally, the electrical contact of the thermocouple as the temperature sensor 22 is much simpler, since it can be positioned within the relatively short ceramic tube 24, extending out from the edge body 16 and thus out of the direct heating area of the heating element 20.The connection to the terminal housing 26, which also accommodates the electrical connections 21 for the heating element 20, allows for a general electrical connection of the radiant heating device 11 in a known manner. Compared to the electrical contacting in the aforementioned DE 10 2022 204 359 A1, the design is also simpler, since there the contact exits the bottom of the radiant heating device or the metallic mounting tray, and the cable has to be routed separately.
Claims
Patent claims 1. A method for operating a radiant heating device, wherein the radiant heating device comprises: a flat and planar support with an edge region, the edge region being located in the outer 70% to 99% of the diameter or width of the support; at least one elongated heating element extending in tracks on the support within a planar heating area; a temperature sensor in the edge region, wherein the temperature sensor is connected to a control device for a power supply for the radiant heating device, characterized by the steps: during operation of the radiant heating device or an electrical device in which the radiant heating device is installed, the temperature sensor detects the temperature for processing in the control device; the control device receives the temperature from the temperature sensor.The control unit is connected to a power supply for the radiant heating device and receives operating information from it regarding the operating mode and / or duration of the radiant heating device, as well as the power level at which the radiant heating device is operated. The control unit stores memory values for temperatures depending on the operating mode and / or duration and the power level during operation of the radiant heating device. By using the temperature measured at the temperature sensor on the one hand and the stored values on the other, a temperature at a defined point on the radiant heating device or a cooktop plate above it is determined. Based on the determined temperature at the defined point on the radiant heating device or a cooktop plate above it, a function is triggered.which is selected from the following group: Warm indicator or hot indicator for the radiant heating device; power reduction for the at least one heating element due to reaching the maximum temperature; temperature-controlled operation of the radiant heating device.
2. Method according to claim 1, characterized in that storage values are stored in the control device which are obtained by the following steps: A radiant heating device of a certain type, wherein the radiant heating device is configured according to the preamble of claim 1, is provided with a reference temperature sensor at a defined point, preferably at a defined point where a maximum temperature prevails above the radiant heating device and / or on a cooktop plate of a hob above it. Operation of the radiant heating device with a variety of different operating durations and operating modes and different power levels and / or temperatures, wherein preferably the radiant heating device is operated intermittently and the at least one heating element is either operated at full power or switched off in such a way that a power level is established on average over time as the average power over time, Measuring the temperature at the temperature sensor and the temperature at the reference temperature sensor, Saving the recorded temperatures, combining the recorded temperature values with regard to operating duration and / or operating type and / or power level.
3. Method according to claim 1 or 2, characterized in that the storage values have been recorded by continuously recording the temperature at the temperature sensor of a radiant heating device of the same construction, which is installed in an electrical device corresponding to a series-produced electrical device, wherein an additional temperature sensor is used to record the temperature at the relevant defined point, wherein the recorded temperature values are correlated, wherein various operating modes and / or operating durations are additionally set and the respective operating mode and / or operating duration are stored together with the correlated temperature values, wherein this is also stored in the control unit for a power supply for the radiant heating device.
4. Method according to claim 2 or 3, characterized in that correction values for the values measured with the temperature sensor can be derived from, on the one hand, information about the previous operation of the radiant heating device and, on the other hand, from the temperatures measured with the reference temperature sensor.
5. Method according to one of the preceding claims, characterized in that a hot indicator is activated for a cooking zone heated by the radiant heating device. This occurs as soon as the temperature at any point on a cooktop plate above the radiant heating element where the cooking area is formed exceeds 50°C.
6. Radiant heating device for carrying out the method according to one of the preceding claims, wherein the radiant heating device comprises: a flat and planar carrier with an edge region, wherein the edge region lies in the outer 70% to 99% of the diameter or width of the carrier, at least one elongated heating element which runs in tracks on the carrier within a planar heating area, a temperature sensor which is connected to a control device of a power supply for the radiant heating device, characterized in that the temperature sensor is arranged on the side of the carrier in the edge region.
7. Radiant heating device according to claim 6, characterized in that the temperature sensor is a thermocouple.
8. Radiant heating device according to claim 6 or 7, characterized in that a metal plate is arranged on the thermocouple or a welded connection of the thermocouple is located on a metal plate, wherein preferably the metal plate has an area of less than 12 mm x 12 mm.
9. Radiant heating device according to one of claims 6 to 8, characterized in that the temperature sensor is arranged at the tip of an elongated support device, in particular is electrically insulated from it, wherein the elongated support device preferably has ceramic or consists of ceramic.
10. Radiant heating device according to claim 9, characterized in that the elongated support device projects inwards over one side or over an edge region of the support for the at least one heating element, preferably extends through an outer edge part that limits the support on the outside, and is attached to a connection housing outside the outer edge part.
11. Radiant heating device according to claim 10, characterized in that the connection housing is attached to the support or to a receiving shell for the support and has electrical connections, wherein the electrical connections have at least go to the temperature sensor and preferably electrical connections go to the at least one heating element, in particular to all heating elements, of this radiant heating device.
12. Radiant heating device according to one of claims 6 to 11, characterized in that the temperature sensor runs outside the heating area or over an area of the carrier that is free from the heating element or is free from all heating elements.
13. Radiant heating device according to one of claims 6 to 11, characterized in that the temperature sensor runs above the heating area and over an area of the support on which a heating element is arranged.
14. Radiant heating device according to one of claims 6 to 13, characterized in that the temperatures recorded in claim 2 or 3 are stored in control devices which are equipped with radiant heating devices of the same type in the same manner.
15. Hob comprising: at least one radiant heating device according to one of claims 6 to 14, a power supply for the at least one radiant heating device, a control device, a hob plate below which the at least one radiant heating device is arranged.