EP1844629B1 - Heating device with temperature sensor and hob with heating devices - Google Patents

Abstract

A hob comprising a plurality of radiant heating devices, each of which is further comprised of a support and a heat conductor mounted thereon. An elongate and tubular temperature sensor having a temperature sensitive element in a glass envelope extends along the support and is embedded therein to such a degree so as to project only slightly upwards. Ends of the temperature sensor with connections extend to the edge of the support or even project beyond.

Description

The invention relates to a heating device, as it is advantageously used for hobs with a cover made of glass or glass ceramic, and a hob with a plurality of heaters.

It is for example from the DE 199 42 967 known to arrange at heaters in the form of radiant heaters an over-temperature fuse in the form of a so-called rod controller with an elongated, rod-like expansion element. Above all, this over-temperature fuse serves not to exceed a maximum permissible temperature at a glass-ceramic plate of a hob which extends above the heating device. It is attached with its housing outside of the radiant heater to a receiving tray. The rod-shaped expansion element protrudes into the interior of the radiant heater and can, for example by staples or upstanding hook-like holder, are fixed. However, the attachment of the housing to the outside of the receptacle with effort, in particular installation effort provided.

The US 4,447,711 shows a temperature sensor, which runs under heat conductors or a plane in which heat conductor lie. There, the temperature sensor is attached in one embodiment to a controller housing, where he hangs there in the air, so to speak. According to another embodiment, the temperature sensor is not held on the support on which run the heating conductors, but on an underlying lower support. In this version, the temperature sensor runs well below the heating conductors.

The DE 2729930 A shows in one embodiment a temperature sensor which is attached to a housing of a temperature controller. There it runs under an upper carrier layer of a carrier, on which the heating conductor is arranged. According to another embodiment, it is in turn attached to a temperature controller housing, but runs well above the heating conductors. He is only attached to its ends.

The FR 2261695 A describes the course of a temperature sensor in a channel on a carrier for heating conductors. Nothing is carried out for the exact fixing of the temperature sensor. The temperature sensor runs well below the heating element.

Task and solution

The invention has for its object to provide an aforementioned heating device and a hob, with which the disadvantages of the prior art can be avoided and in particular the arrangement of a temperature sensor can be simplified to a heater.

This object is achieved by a heating device with the features of claim 1 and a hob with the features of claim 13. Advantageous and preferred embodiments of the invention are set forth in the further claims and are explained in more detail below. The wording of the claims is incorporated herein by express reference.

The heating device has both a temperature sensor and a carrier, wherein an elongate heating conductor is arranged on or on or above the upper side of the carrier. The heating conductor is in particular designed and arranged such that it forms a substantial part of the surface the carrier covered, for example, spiral, meandering or a mixture thereof. According to the invention, the temperature sensor is predominantly or even exclusively fastened or held on the carrier only, whereby it is also arranged on the carrier, that is to say it touches it. This means that it is advantageously arranged with a substantial part of its length or extension on the carrier or bears against it. In this way, especially in comparison to the aforementioned prior art to a mounting on a receiving tray odgl. the carrier be waived. Furthermore, for example, a pre-assembly of the carrier and temperature sensor can be made into a structural unit, regardless of the type of a receiving tray used, and in particular as well as training without receiving tray are possible.

The temperature sensor is advantageously elongated. In particular, it has a kind of simple or double, in particular bent tube. Therein a sensitive element can be arranged.

Furthermore, the temperature sensor is advantageously designed for temperature detection via electrical evaluation, that is not via mechanical expansion behavior due to temperature change or the like.

Thus, it is possible to make it both smaller and without moving parts, especially since no expansion forces or the like. have to act on him or be recorded.

In one embodiment of the invention, the temperature sensor may be at least partially embedded in the carrier or run in a channel in the carrier. Advantageously, it is in substantially complete contact with the material of the carrier and may rest against the carrier along a substantial part of its length. Thus, a substantially complete support or storage on the carrier can be made for the best possible support. An embedding of the temperature sensor in the carrier or the carrier material also allows a determination against lateral movements. It should be noted in particular that a holder of the temperature sensor on the support on the one hand in the lateral direction and on the other hand in the vertical direction can be realized in each case independently or in combination with each other in an advantageous manner. A channel or a recess in which the temperature sensor runs can be provided for this purpose. It is also possible that the carrier has a recess or a channel to accommodate electrical leads for the heating conductor on the carrier or lead. Here, the temperature sensor can be introduced at the same time or the recess can have a double function. It is also possible to produce the recess for the temperature sensor by a sandwich construction with correspondingly preformed support parts. One of them then has the recess, overlying parts can cover the recess at least partially again, although windows can be provided upwards.

It can be provided that the carrier has a substantially flat or uniform surface, at least in some or in essential areas. About this, the temperature sensor something survive, so to speak not completely embedded in the carrier. The supernatant can either be only a small piece, for example, to make especially in this area the temperature detection.

Alternatively, it is also possible that the aforementioned carrier having a substantially planar surface or flat shape has a survey or elevation, in which the temperature sensor extends. An embedding of the temperature sensor in such a survey can be advantageously designed so that a substantial part, in particular the largest, of the temperature sensor is embedded in the carrier or is covered by the carrier material of the survey. In continuation of this idea, it is also possible to provide on a substantially flat support an aforementioned survey, in which the temperature sensor is largely embedded or is supported by it. However, the temperature sensor can extend laterally free of the survey with substantial length ranges while resting on the support, but largely free to make undisturbed by effects of the wearer temperature detection. In this case, such a survey acts as a mechanical support of the temperature sensor. An elevation can also run at a distance and be designed as a lateral protection.

Furthermore, it is also possible to arrange the temperature sensor substantially below the plane or top of the flat carrier, so to speak, under the heating conductors. In this case, the temperature sensor can either be exposed upwards or be largely covered with carrier material. When evaluating such a temperature sensor, it should be noted that the temperature at the heating conductors or in an area above the heating conductors can not be detected directly by embedding in the carrier material. Either correction factors can be used here. Alternatively, with a such arrangement, the temperature of the carrier are very well detected, if so desired.

In a fundamentally different embodiment, the temperature sensor can be arranged on the carrier, wherein it is substantially free or not embedded in the carrier. In any case, it is not embedded with functionally important parts or parts whose embedding means an effect on the temperature detection, for example because such a sensitive element of the temperature sensor is shielded from the carrier material. An attachment can be made by holding means which, for example, cross-brackets, protruding attachment members or the like. include.

In a further embodiment of the invention, it may even be provided or desired that the temperature sensor is shielded from direct irradiation by the heat conductors lying laterally next to it. This can be done advantageously by a shield, for example in the form of a layer of carrier material. However, it is not necessary to embed the temperature sensor particularly deep in the carrier, but it can also be provided relatively narrow walls or webs. Above all, the temperature sensor should be exposed obliquely upwards to the side and directly upwards for the best possible detection of the temperature at, for example, a glass-ceramic hob plate extending above it.

As already mentioned above, the temperature sensor advantageously has a sensitive element for the measurement. This is advantageously metallic or a piece of metal or metal wire. A sensitive element is advantageously elongated, in particular in order to be able to detect a temperature over a relatively large area. The sensitive element should be arranged in an envelope, which preferably consists of temperature- and / or radiation-permeable material. Especially preferred here is glass, for example as a glass tube. The glass can eg by coloring, doping or the like. be changed or optimized in its transmission properties. There are also covers made of metal possible.

The sensitive element can advantageously be contacted electrically via connection wires of the temperature sensor to the outside. If it is arranged in a glass envelope, then the connecting wires must be inserted here, whereby they are usually melted down. It is advantageous if these melts are outside the heater or outside the carrier and especially outside the direct heating effect of the heater to avoid excessive thermal stress or destruction. Advantageously, the temperature sensor generally protrudes laterally beyond the heating device with one end, in particular a covering end with electrical connections. So a contact is possible, for example by welding or soldering or with a detachable connection.

In a further embodiment of the temperature sensor, a sensitive element may be guided in an elongated form parallel to an aforementioned connecting wire, advantageously within the envelope. So it can be connected to this, advantageously welded.

In a further embodiment of the invention, it is possible to form the enclosure as a capillary, in which the sensitive element extends. In this case, it can at least partially touch a wall of the capillary, wherein it can also rest in larger areas or on a longer section, in particular it can be supported.

The temperature sensor can advantageously be arranged on the carrier in such a way that heating conductors, viewed in the plane of the carrier, are located only laterally next to the temperature sensor. However, they are not heat conductors present, which are higher or lower. In particular, all the heating conductors of the heating device run approximately in one plane or define such a plane.

In another embodiment, the temperature sensor may also be at an angle to the plane of the otherwise substantially flat carrier or its upper side. In this case, it is advantageously covered in a longitudinal region by a layer of the carrier material. In another longitudinal area it is exposed, for example at the end. There he can record the temperature very well.

As a sensitive element, a compound of metal and ceramic can be used. The ceramic may have PTC properties, wherein it may contain, for example, at least one high-temperature superconductor. Furthermore, the sensitive element can advantageously have a low heat capacity, whereby, above all, a rapid response of the temperature sensor is possible. It may have a temperature coefficient of resistivity greater than that of platinum, such as silver or tungsten. It can also be designed so that the temperature dependence of its electrical resistance compensates or reduces the deviation between the temperature of a glass ceramic plate extending above the heating device and that which detects the sensitive element itself within certain temperature ranges.

Another possibility for a sensitive element is an optical temperature sensor.

Furthermore, it is possible to arrange such a sensitive element on its own sensor carrier, for example made of ceramic. In particular, it may be enveloped to the outside with a ceramic cladding, for example, consisting of several parts. The carrier may also be the sensor element itself.

Such a sensitive element can be advantageously produced by conventional thick film or thin film processes. In particular, it can be applied to a sensor carrier.

The fact that the temperature sensor can be placed on the support or even a piece embedded in it, it is possible to bring the heater or the heat conductor closer to the underside of an overlying hob plate. Thus, the size can be reduced and the transmission of heat output via radiation can be increased by reduced distance. In particular, the heating wire can radiate freely and be exposed or open at the top. So its heating effect is best.

An inventive hob can have one or more heating devices, wherein these are formed as described above. Furthermore, it has a cooktop plate, below which the one or more heating devices are arranged. In this case, the distance between the bottom of the hob plate and the heaters is reduced or very low in relation to known hobs. Advantageously, it is less than 2 cm, more advantageously even only 1 cm or even less. Thus, an aforementioned reduction of the overall height is possible. Furthermore, a higher power input of the heater through the hob plate can be made possible in a standing thereon cookware. In this case, all the heating devices are preferably constructed according to the same principle or each have, as it were, lowered temperature sensors.

Furthermore, it is possible to save a separate connection block.

1. a) einfaches Füllmaterial, wie beispielsweise Glaspudermehl oder Schaumglas, in eine Aufnahmeschale wie einen Blechteller einlegen,
2. b) den Temperatursensor einbringen und
3. c) eine Dämm-Schicht mit pyrogener Kieselsäure darüber einbringen.

By maintaining the entire height or using a proportion of the gained height, the heat insulation can be made stronger or cheaper. For example, the thermal insulation can be completely or partially replaced by a foam glass or sandwiched structures. Thus, the heating of the cooking appliance containing the radiator can be reduced. Such a heater can be manufactured, for example, by the following steps:

1. a) insert a simple filler material, such as glass powder or foam glass, into a receiving tray such as a sheet metal plate,
2. b) insert the temperature sensor and
3. c) introduce an insulating layer with fumed silica over it.

A heat conductor can then be attached over the insulating layer.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections as well as intermediate headings does not restrict the general validity of the statements made thereunder.

Brief description of the drawings

Fig. 1

eine vergrößerte Darstellung einer Ausführungsform eines U-förmigen Temperatursensors mit Glasrohr,

Fig. 2

eine Darstellung zweier Möglichkeiten, wie an einer erfindungsgemäßen Heizeinrichtung ein Temperatursensor aus Fig. 1 teileingebettet angeordnet ist,

Fig. 3

eine Variation der Heizeinrichtung aus Fig. 2, bei der der Temperatursensor jeweils in einem vorgefertigten Kanal angeordnet ist,

Fig. 4

eine weitere Variation der Heizeinrichtung aus Fig. 2, bei der der Temperatursensor vollständig in einen Träger der Heizeinrichtung eingebettet ist,

Fig. 5

zwei weitere Variationen der Heizeinrichtung aus Fig. 2, bei der der Temperatursensor einerseits vollständig auf den Träger der Heizeinrichtung aufgesetzt ist und andererseits teilweise herausragt und

Fig. 6

ein erfindungsgemäßes Kochfeld im Seitenschnitt.

Embodiments of the invention are shown schematically in the drawings and will be explained in more detail below. In the drawings shows:

Fig. 1

an enlarged view of an embodiment of a U-shaped temperature sensor with glass tube,

Fig. 2

an illustration of two ways, such as on a heater according to the invention, a temperature sensor Fig. 1 is arranged partially embedded,

Fig. 3

a variation of the heater Fig. 2 in which the temperature sensor is arranged in each case in a prefabricated channel,

Fig. 4

another variation of the heater Fig. 2 in which the temperature sensor is completely embedded in a support of the heating device,

Fig. 5

two more variations of the heater off Fig. 2 in which the temperature sensor on the one hand completely placed on the support of the heater and on the other hand partially protruding and

Fig. 6

an inventive hob in side section.

Detailed description of the embodiments

In Fig. 1 a temperature sensor 11 is shown as an exemplary embodiment. The temperature sensor 11 is generally elongated, wherein it has a U-shaped glass tube 13 as a shell. The upper part 14a and the lower part 14b of the glass tube 13 run very close to each other. Alternatively, the two parts could have more distance. It is also possible to construct the temperature sensor with only one and substantially straight or elongated tube, preferably made of quartz glass.

In the glass tube 13 is a schematically illustrated elongated sensitive element 15. This can be very diverse and be both a kind of metal wire of the corresponding metal as well as a sensitive layer which is applied to a support. An electrical contact to the sensitive element 15 via connecting wires 16a and 16b, which are welded thereto. At the point, where the leads 16 exit from the glass tube 13, fuses 17a and 17b are provided. Thus, it is also possible, for example, to provide a protective gas atmosphere in the interior of the glass tube 13 or even a vacuum.

In Fig. 2 is a basically first embodiment of the invention shown. A heater 20 has a disk-shaped or plate-shaped carrier 22, which consists of thermal insulation material, such as in the DE 2551137 A or the EP 750 444 A is described. Then a heating conductor 26, in the example shown, an upright Heizleitererband. This may be partially embedded in the carrier 22 or have holding members which extend into it. The carrier 22 is substantially flat at its top and all heating conductors 26 also extend in a plane.

The difference in Fig. 2 between the left example and the right example is in the elongated elevation 23 in the right hand example. In both cases, the temperature sensor 11 is indeed completely embedded in the carrier 22 with the lower part 14b. The upper part 14a looks out about halfway or over the thermal insulation material of the carrier 22 via. In the right example, it can be seen that without elevation 23, the upper part 14a would protrude beyond the carrier 22 or would lie above it. Thus, here the survey 23 in addition to a mechanical stabilizing effect bring a certain shield to the side. In particular, this is advantageous if it is not possible to embed the temperature sensor 11 deeper in the carrier 22.

It is in Fig. 2 Also to recognize that the ends of the glass tube 13 and the upper part 14a and the lower part 14b laterally from the support 22 at least a small piece look out or are fully accessible. In particular, this also applies to the melts 17a and 17b, so that the connecting wires 16a and 16b are completely free or not covered by the material of the carrier 22.

The shape of the survey 23 may vary. In addition to a shown, relatively gentle increase, the increase may also be steeper. Furthermore, the elevation 23 may also be wider or longer than shown. However, it advantageously extends only in the immediate area around the temperature sensor 11, since otherwise it could adversely affect the attachment of the heating conductors 26. So the production cost is low.

Out Fig. 2 is the basic principle to recognize that in this embodiment, the temperature sensor 11, although embedded in the carrier 22 and in its material, but still protrudes a piece beyond it or. Above all, it is not covered at the top, so that it can detect, for example, heat radiation from a cooktop panel located above it.

In Fig. 3 is again shown in a split representation of a heater 120 according to the invention according to a second basic embodiment. The carrier 122 each has elongated, approximately U-shaped channels 124. While in the presentation after Fig. 2 For example, if the temperature sensor can already be compressed together with the loose thermal insulation material in the initial state to form the carrier 22, here the channel 124 is present even before the temperature sensor 111 is introduced. The attachment of the temperature sensor 111 in the channel 124 can be done by tailor-made training with pushing. Likewise, sticking or retaining clips or the like. possible. Again, the ends of the upper part 114a and the lower part 114b or the connecting wires 116 should be easily accessible or a piece over the side edge of the carrier 122 projecting.

Furthermore, it can be seen how a supply line 127 to the heating conductor 126 at least partially extends in the channel 124 and is guided to the outside. In order to more easily reach the heating conductor 126, the channel 124 or a part thereof may also be led up to the heating conductor 126. In this case, the temperature sensor 111 occupies only a part of the entire length of the channel 124.

In the left half of the Fig. 3 the upper part 114a of the temperature sensor 111 projects over the upper side of the otherwise flat carrier 122. In the right half, however, a survey 123 is provided on both sides of the channel 124. This causes the same depth of embedding of the temperature sensor in the carrier this is also completely shielded to the side by the thermal insulation material. Thus, the temperature sensor 111 is not above the carrier 122 or its material at any point. However, as can be seen, it is completely open at the top, ie in the direction in which it is to measure a temperature, or it can detect heat radiation very well.

In Fig. 4 is again shown in a third embodiment in a split representation, as the temperature sensor 211 is completely embedded in the carrier 222 and its material. In both cases it is not over or free at any point. Only the ends look out at the side again.

It should also be noted, similar to in Fig. 3 in that in the left half the temperature sensor 211 lies substantially below the heating conductor 226. So he could walk under them too. In the right half, on the other hand, the upper part 214a of the temperature sensor 211 would not be embedded without the elevation 223 or be exposed and protrude beyond the material of the carrier 222. Likewise, without the surveys 123 in Fig. 3 the upper part 114a are exposed to the side, heat radiation from the heating conductors 126 could act on it.

Similar to Fig. 2 can be executed in accordance with Fig. 4 the temperature sensor 211 may be crimped together with either the thermal barrier material to the finished carrier. Alternatively, not shown recesses could be provided, similar to the channels in Fig. 3 , in which the temperature sensor is inserted. These are then not open at the top.

In Fig. 5 on the left a fourth basic version is shown. Here, the temperature sensor 311 is placed on top of the carrier 322 and is completely on this on or above her. An attachment is made by the retaining clip 325, which surrounds it like a bow and is anchored in a manner not shown on the support 322. For this purpose, it can either be glued or extending into or protruding into it, for example, with protruding projections. On the representation of heating elements is omitted here.

Again, it is possible, on one or both sides of the temperature sensor 311 surveys similar to those of the Fig. 2 to 4 provide that project upwardly from the carrier and either fix the temperature sensor 311 laterally or cover at least partially laterally. The retaining clip 325 can then either extend into the survey or this project beyond the side.

In Fig. 5 On the right, a fifth basic embodiment is shown, in which the temperature sensor 411 extends obliquely to the surface of the carrier 422. With one end 411 'he protrudes from the carrier and can make the temperature measurement in this area, for example. The ends of the tubes 414 with the terminals 416 in turn protrude laterally and are accessible for contacting.

In Fig. 6 an inventive hob 30 is shown with a hob plate 31, preferably made of glass ceramic. Below this, a heater 20 is similar to that in the left half in FIG Fig. 2 arranged. Shown here is also a receiving tray 29, in which the heater 20 is. The receiving tray 29 is pressed against the underside of the hob plate 31.

It can be seen that the heating conductors 26 project beyond the upper part 14a of the temperature sensor. They have a certain distance to the underside of the hob plate 31, which is determined by the side edge of the receiving tray. However, this distance is in the range of a few millimeters or about one centimeter and is thus considerably smaller than in previous radiant heaters. For some of these, the temperature sensor still has to run between the heating conductors and the hob plate and must maintain a certain minimum distance.

The connecting wires 16a and 16b of the temperature sensor 11 are guided to an evaluation or control, not shown. This evaluates together with the temperature sensor 11 and the sensitive element 15, the detected temperature.

Claims (14)

1. Heating device preferably for hobs (30) with a cover (31) of glass or glass ceramic, the heating device having a temperature sensor (11, 111, 211, 311) and a support (22, 122, 222, 322) on whose upper side a heat conductor (26) is arranged, the temperature sensor being fastened/mounted exclusively on the support and arranged thereon, the temperature sensor (11, 111, 211) being at least partially embedded inside the support (22, 122, 222) or running inside a channel (124) therein, wherein the temperature sensor (11, 111, 211) runs inside an elevation (23, 123, 223) of the otherwise substantially flat support (22, 122, 222) and is substantially covered by the support material, the major part of the temperature sensor being embedded in the support and an arrangement of the temperature sensor (11, 111, 311) on the support (22, 122, 322) being designed such that heat conductors (26, 126, 326) are only located laterally next to the temperature sensor and not higher or lower when seen in a plane of the support.
2. Heating device according to Claim 1, wherein the temperature sensor (11, 111, 211, 311) is designed elongated, preferably tubular, being in particular bent in a U-shape.
3. Heating device according to Claim 1 or 2, wherein the temperature sensor (11, 111, 211, 311) is designed for temperature recording via electrical evaluation.
4. Heating device according to one of the preceding claims, wherein the temperature sensor (11, 111, 211) is in largely full contact with the support material or is directly embedded therein.
5. Heating device according to one of the preceding claims, wherein the support (122) has a recess (124) in which run the temperature sensor (111) and an electrical lead (127) for the heat conductor (126).
6. Heating device according to Claim 4 or 5, wherein the temperature sensor (11, 111, 211) projects towards the side on which the heat conductor (26, 126, 226) is arranged somewhat beyond the otherwise substantially flat surface of the support (22, 122, 222), preferably by a maximum of one third.
7. Heating device according to one of the preceding claims, wherein the temperature sensor (11, 111, 211) is shielded from direct radiation from the heat conductor (26, 126, 226) preferably by a layer of the support material, in particular by embedding the temperature sensor in the support (22, 122, 222) or by lateral elevations (23, 123, 223) of the support over the temperature sensor.
8. Heating device according to Claim 4 or 5, wherein the temperature sensor (411) is arranged obliquely to the plane of the otherwise substantially flat support (422) or the upper side on which the heat conductor (426) is arranged, preferably being covered in one longitudinal area by a layer of the support material and exposed in another longitudinal area.
9. Heating device according to one of the preceding claims, wherein the temperature sensor (11, 111, 211, 311) has a sensitive element (15), in particular in elongated form, the sensitive element being arranged in an envelope (13, 14) preferably of electrically insulating material such as glass, and wherein in particular fused enclosures of the connecting wires of the temperature sensor (11, 111, 211, 311) to the sensitive element (15) are in the glass (13, 14) outside the heating device (20, 120, 220, 320) or outside the support (22, 122, 222, 322).
10. Heating device according to Claim 9, wherein the sensitive element (15) has a bond between metal and ceramic, the metal and/or ceramic having PTC properties and in particular at least one high-temperature superconductor.
11. Heating device according to Claim 9 or 10, wherein the sensitive element (15) is made using a thick-film and/or thin-film manufacturing method.
12. Heating device according to one of the preceding claims, wherein the temperature sensor (11, 111, 211, 311) projects with one end (17) having electrical connections (16) beyond the heating device (20, 120, 220, 320) or the lateral edge of the support (22, 122, 222, 322).
13. Hob with several heating devices (20) according to one of the preceding claims, the hob (30) having a hob plate (31) and the heating devices being arranged underneath, wherein the distance between the underside of the hob plate and the heating devices (20) is very small.
14. Hob according to Claim 13, wherein the heating devices (20) have a heat conductor (26), in particular a heating wire freely radiating and exposed/open to the top, and the distance between the underside of the hob plate (31) and the heat conductor is less than 2 cm, preferably less than 1 cm.

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