EP1276350A2 - Electrical radiating heating device with active sensor recognizing cooking ustensil - Google Patents

Abstract

The radiant heating element comprises a sensor (21) which is formed straight and without ties. The sensor has section which runs over the heating zone (17) which in turn has a straight electric conductor. The heating element is arranged on a metal plate which has two connections for the sensor. The sensor is electrically insulated against the metal plate in at least one end region (22). An Independent claim is also included for a hub with electric heating elements.

Description

The invention relates to an electric radiant heater with a active sensor to detect the positioning of a cooking vessel a hotplate covering the radiator according to the preamble of claim 1.

Such sensors, as known for example from DE 196 03 845 A1 are used to recognize if and where a cooking vessel on the hotplate. Only when the cooking vessel is on the Heating activated. This is done on the one hand to waste energy due to the fact that cooking vessels are not attached and, on the other hand, the risk of Burning or destruction of objects by hot, so to speak Avoid open hot plates.

The sensor according to DE 196 03 845 A1 is designed as a loop made of wire, the essentially round shape between the radiator and Hotplate runs. The fitting of a corresponding metallic Cooking vessel causes a change in the inductance of the sensor loop. This change is set up by associated electronics of a cooking vessel is detected. Depending on this, the heating can be activated be as intended. Difficulties arise itself from the attachment of the sensor to the radiant heater. Furthermore, there are problems with the mass of the sensor, especially in a so-called drop test, in which the sensor, for example can damage a glass ceramic plate as a hob.

Task and solution

The invention has for its object one mentioned to create electric radiant heater, in which the attachment of the sensor on the radiant heater is simplified and the sensor has an improved structure.

This object is achieved with a radiant heater Features of claim 1. Advantageous and preferred training the invention are contained in the subclaims and are set out below described in more detail. The wording of the claims is by express Reference made to the content of the description.

According to the invention, the sensor is in contrast to the known and customary ones round sensor loops or coils designed without loops. It runs essentially in a straight line, preferably at least in the essential sections of its course. Particularly preferred it runs exclusively in the area of the radiant heater or the heating zone essentially straightforward. Loopless means in context with the present invention in particular that the sensor does not form a completely or largely closed loop. Prefers the sensor does not limit any area in its course.

Under "substantially straight" should not be too wavy or similarly designed sensor can be understood. Finally runs this can also describe it in one direction or its course to let.

A sensor according to the invention has the advantage that the structure can be significantly simplified. On the radiant heater is not attach an entire circumferential loop, which may also has several turns, but only straight sections. These can, for example, have at least one end Edge of the radiant heater or an insulation surrounding it be attached. Furthermore, loop-shaped sensors have the disadvantage that that they do not exactly capture the central zone of the radiant heater, because they don’t cross them directly. Because of its circumferential, no section through this central loop-shaped character Area. A straight sensor over this central area on the other hand, leading is not a problem.

The invention has surprisingly succeeded, for example with two wires stretched in parallel over a multi-circuit radiator to recognize the placement of a cooking vessel as well as its size and even its position.

Furthermore, it was surprisingly found that the sensor only one May have section extending over the heating zone, for example can be designed as a straight electrical conductor. It can be from one Edge of the radiant heater to above its center, preferably to to the other edge. Such a sensor closes at all no area. Surprisingly, here is the function or the accuracy of detection just as good as the parallels described above Ladders as sensors. Depending on the set switching threshold of an associated one Electronics can decide whether a cooking vessel is attached or whether this cooking vessel size or position is accepted.

The sensor advantageously runs across a heating zone or the entire one Radiant heaters. Here it is, especially with a sensor with a single conductor or section, possible with great advantage, Radiant heaters to use, the one in the radiant heater have essential supporting or contained metal plate. The metal plate can be designed as a return conductor or second connection for the sensor his. This means that complex additional connection work can be carried out here omitted. It has surprisingly been found that this Function of such a cooking vessel detection sensor is not impaired becomes. This can look like the sensor on at least one of its End areas opposite the metal plate of the radiant heater electrically is isolated. With this insulated end area, it is with one from the outside accessible first electrical connection connected. The other The end of the sensor is electrically connected to the metal plate, directly or indirectly. In a particularly simple embodiment, a second one is required electrical connection only at any point on the metal plate to be attached to be electrically connected to it.

A particularly preferred embodiment looks such that a connection possibility or a connector for the sensor both connections contained in a terminal block. This can be done near a Sensor end of the connecting block on the radiant heater or Metal plates are attached. When using the metal plate as Return conductor or second electrical connection, it is very easy to tap this signal at any point or the terminal block to be placed very close to one end of the sensor.

The sensor advantageously runs centrally over the heating area of the radiant heater. This can ensure that one on the associated Cooking place set cooking vessel in almost every sensible position covers the sensor and enables detection. With a radiant heater with multiple heating areas, the sensor can do more as a heating area, especially all heating areas.

It is also possible to cover the sensor only in separated areas to arrange. A position detection of a cooking vessel for this separated area can be reached. This is for example at additional heaters arranged laterally for elongated roasters or the like. advantageous.

According to one possibility of the present invention, it is possible Attach the sensor to the radiant heater in such a way that it mounted radiant heater with a short distance below one Cooking plate on which the radiant heater is mounted runs. This small distance can be 0.1mm to 10mm, preferably very be small and a few 1/10 mm. As a measure of this distance can also the upper edge of a surrounding the radiant heater Isolation plates or the like can be taken in the assembled Condition on the underside of the hotplate.

In a further embodiment of the invention, the sensor can at least have a height adjustment at one of its ends, so that a desired distance can be set exactly. Such a height adjustment For example, an elongated hole, preferably in perpendicular to the Level of the radiant heater extending direction, on the radiant heater show yourself. Along this slot, the The height of the sensor can then be adjusted.

On the one hand, it is possible to make the sensor rigid, preferably as thick wire or tubular. For a tubular sensor offers in particular a metal pipe that is electrically insulated from the outside can. In one embodiment of the invention, the sensor with a rod regulator commonly used for radiant heaters be combined. The metal outer tube of the rod regulator can be used form the sensor or be used as an electrical conductor for it. This allows a combined unit to be created that is considerable requires less installation effort.

A normally used rod regulator with a residual heat contact can be advantageous be grown on the radiant heater and as Be designed sensor. If the residual heat contact of the rod regulator is not required, the space that has become free in the rod controller can be used as a connection block for the sensor connection.

According to another possibility of the invention, the sensor can be elastic or be flexible. A wire, a strand or a metal band. These can cover at least a section of the Heating area be stretched and gain their stability by stretching.

In the context of the invention, spring means for compensating a thermally induced change in length of the sensor may be provided. alternative or in addition to this, the spring means for storage at least one end of the sensor and / or to maintain the Voltage and thus serve the shape of the sensor. It should be noted here that if the position of the sensor matters, the spring means should be constructed in such a way that it defines an exact position Allow attachment. Furthermore, the spring force on the Time / temperature proof limit of the sensor material or on the cross section of the sensor. This can ensure that the system sensor / spring means is optimally coordinated. A leaf spring is preferably used as the spring means, which at a Execution possibility of the invention even from the metal edge of the Support plates for the radiant heater are punched out and exposed can be.

It is possible to use at least one end of the sensor by means of spring means to attach or store on the radiant heater. there can the spring means against a metal plate for receiving the Radiant heater be electrically insulated. Serve particularly preferably however, the spring means just for the electrical connection of the sensor the metal plate, which then as a return conductor or second electrical connection is used.

The sensor should be scale resistant to the high temperatures not permanently attacked or damaged in the heating zone become. Furthermore, it is advantageous if the material of the sensor does not have a Curie point. Otherwise, adulteration of the Show measurement results.

In addition, it is one commonly used described above Rod controller possible to install a precious metal temperature measuring resistor. Such measuring resistors are, for example, a PT 100 or a PT 1000. The precious metal temperature measuring resistance can the ceramic part of the rod regulator can be replaced. Here it can Outer tube of the rod regulator as a sensor and as a holder for the precious metal temperature measuring resistor be trained.

Finally, the invention also comprises a cooktop with a plurality of radiant heaters, wherein at least one of the radiant heaters is advantageous all, can be designed in the manner described above.

A necessary sensor electronics for the evaluation of signals from the sensor should of course be available. You can be trained like this be, as described for example in DE 196 03 845 A1, the Content by express reference to the content of this description is made

The above and further features go beyond the claims also from the description and the drawings, the individual features each individually or in groups in the form of Subcombinations in one embodiment of the invention and others Areas to be realized and advantageous as well as protectable Can represent designs for which protection is claimed here becomes. The division of the application into individual sections and subheadings limits the statements made under these not in their generality.

Brief description of the drawings

Fig.1

einen Querschnitt durch einen erfindungsgemäßen Strahlungsheizkörper, bei dem ein Stabregler den Sensor bildet,

Fig. 2

eine Draufsicht auf den Strahlungsheizkörper aus Fig. 1,

Fig. 3

einen Querschnitt durch eine alternative Ausführung mit einem gespannten Draht als Sensor und

Fig. 4

eine Draufsicht auf den Strahlungsheizkörper aus Fig. 3.

Embodiments of the invention are shown in the drawings and are explained in more detail below. The drawings show:

Fig.1

3 shows a cross section through a radiant heater according to the invention in which a rod regulator forms the sensor,

Fig. 2

2 shows a top view of the radiant heater from FIG. 1,

Fig. 3

a cross section through an alternative embodiment with a tensioned wire as a sensor and

Fig. 4

3 shows a top view of the radiant heater from FIG. 3.

Detailed description of the exemplary embodiments

Figures 1 and 2 show in cross section an inventive Radiant heater 11, which is essentially formed in the usual way is. That means in a metal plate 12 with the side pulled up Edge 13 is a flat insulating body 14 with a peripheral edge piece 15 arranged. The heat conductor 16 of the radiant heater is on the insulating body 14 laid, for example in meandering turns, see FIG. 2 on the right is a connecting block on the metal plate edge 13 18 attached to a bar controller. In addition, there are other electrical ones Connections 19 are provided for the heating conductor 16 of the radiant heater 11.

The tube 21 of the rod regulator of the connecting block 18 runs across the entire radiant heater 11 or metal plate 12 away. With its left end 22 is mounted in the insulating edge piece 15 or even stands a little bit further.

According to the invention, the metal tube 21 of the rod regulator is used as a pot detection sensor educated. As can be seen from Fig. 2, the Sensor 21 over the entire metal plate 12 or radiant heater 11 away and thus in any case covers one formed by the heating conductors 16 Heating zone 17. The electrical contacting of the pipe or sensor 21 takes place in the right area on the one hand by the sensor either directly with the metal plate 12 or its edge 13 via the attachment of the stick controller is connected as grounding. Since the sensor 21 runs through the metal plate edge 13 can here as another possibility electrical contacting, for example by simple concerns or corresponding resilient contacting means can be provided. The electrical contacting of the other left end of the sensor 21 takes place at the end 22, which, as can be seen in FIG. 1, both by the edge piece 15 and through the metal plate edge 13 extends and a Protrudes pieces over the edge 13. One attached to the end 22 Piece of flexible metal wire 24 is to a pin 25 of a terminal block 27 out. The connecting block 27 is on the metal plate edge 13 attached and consists in the usual way of insulating, preferably ceramic material. It is important that the sensor end 22 no contact with the metal plate edge 13 in the area of the opening Has. For this purpose, the opening can be made sufficiently large be, since a securing of the end 22 anyway by pushing through through the insulating edge 15. Another, more reliable The method is to use the breakthrough or a hole or cutout a kind of electrically insulating sleeve, for example made of plastic or Ceramics to isolate the inside. In this way, storage of the sensor end 22 also take place on the metal plate edge 13.

The metal plate edge 13 is in turn via a further flexible metal strand 28 connected to the second plug-in tab 26 of the connecting block 27. Thus, the sensor 21 is contacted on one End over the sensor end 22 and the metal wire 24. At the other end it takes place over the metal strand 28 and the plate rim 13. As an alternative to the Metal wire 28 could connect the connecting lug 26 directly to the metal plate 12 be connected or even bent out of it.

As alternatives to the possibility according to FIGS. 1 and 2, it is conceivable in the area of the connecting block 18 of the rod regulator or sensor 21 To provide plug connector lug 26. So that the signal line could the metal plate is omitted, this brings electrical or functional however no clear advantage. For this it is very important if a single terminal block 27 for both connections 25 and 26 of the Sensor 21 is present, so that the assembly or contacting very simple and error-free using plugs or the like is. In this configuration, it would also be possible to remove the metal strand 28 from the connecting block 27 to the other end of the sensor 21 in the area of the connecting block 18 of the rod regulator. This is true possible, but means significantly increased effort and is therefore compared to the presented and described possibility consuming.

Furthermore, in the embodiment according to FIGS. 1 and 2 it is possible via the attachment of the terminal block 18 of the rod regulator and / or via the bracket of the other end 22 of the sensor 21, its position and thus future location below a glass ceramic plate that the Radiant heater 11 covers, to fix or adjust.

A similar radiant heater 111 is shown in FIGS. 3 and 4 with a metal plate 112, a metal plate edge 113, an insulating body 114 and two annular edge pieces 115a and 115b. The inner Edge piece 115a divides the heating zone into an inner one above the heating conductors 116 Heating zone area 117a and an outer heating zone area 117b on. A rod regulator 130 is shown in part in FIG. 4 and corresponds a conventional rod regulator to protect against overtemperature, has no connection here with the sensor function.

A leaf spring 131 is screwed or screwed onto the right metal plate edge 113 riveted, with its long resilient leg at an angle of protrudes about 20 ° from the metal plate edge 113. At the end of the leaf spring 131, a sensor wire 121 is attached, the attachment being electrically conductive is. The sensor wire 121 runs across the radiant heater 111 each through corresponding cutouts 133 in the edge pieces 115a and 115b, covering the heating zone areas 117a and 117b.

At the left end of the metal plate 112 or its edge 113 is a connection block 127 attached, which corresponds to that of FIGS. 1 and 2. The sensor wire 121 is directly on an upstanding Section of a plug terminal lug 125 attached in the terminal block 127 such that it is straight from the leaf spring 131 by tension is held. In accordance with the sensor contact of FIG. 1 and 2 is the other plug tab 126 by means of a flexible metal strand 128 with the metal plate edge 113 and thus over the leaf spring 131 connected to the sensor 121. In this way, sensor 121 is over the two plug-in terminal lugs 125 and 126 in a single terminal block 127 contacted. The advantages of this single connection point as well as alternatives to that correspond to the ones above to the 1 and 2 have been described.

From the connecting block 27 or 127, a connecting cable to one corresponding cooking vessel detection electronics. This can with other electronics to control the radiant heater or an entire hob can be combined.

3 and 4, it is possible to by the Terminal lug 126 protruding portion on which the sensor wire 121 is attached, flexible in the direction of the sensor in the manner of a leaf spring or To design the same. In this case it would be possible the other Attach the end of the sensor 121 directly to the metal plate. So could the leaf spring 131 can be saved together with fastening. As another option a corresponding strip could be punched out of the plate rim 113 and bent out laterally to form a leaf spring 131 or their elaborate attachment to replace.

It is also conceivable to use a rod regulator with a sensor tube or a stiff sensor from the edge just a little way over the center of the radiant heater. There can be introduced from below, the sensor holding portion of a metal part of both the Sensor attached as well as an electrical contact at the end can be achieved. This can then be done in analogy to the flexible metal strands be led to a terminal block or the like, the metal strands should be isolated from this. This version can also be used with a flexible wire can be implemented as a sensor accordingly.

Instead of a sensor wire 121, in the embodiment according to FIGS. 3 and 4, a thicker wire, possibly not flexible, can also be used. Here too, the leaf spring 131 can have corresponding spring means for fastening be used at at least one end.

It is possible within the scope of the invention to connect one end of the sensor directly to attach a terminal lug of a terminal block. That has the Advantage that any other attachment for this end is superfluous. at contacting a sensor end by means of or via the metal plate or its edge is to be careful that the sensor is at its other End is insulated from the metal plate.

It can be seen from the two exemplary embodiments that a Attachment of a sensor, which in particular consists of only one straight ladder exists, is very easily possible. This will only be two attachment points needed. Another great advantage of these embodiments consists of both connections and connection leads by using the metal plate as a ladder are simple. By attaching the sensor with one end to the Metal plates can also achieve a significant simplification in construction here become. This means less assembly work and therefore less Costs and sources of error.

Claims (16)

Electric radiant heater (11, 111) with an active sensor (21, 121) for detecting the positioning of a cooking vessel on a hotplate covering the heater, in particular a glass ceramic plate, the sensor (21, 121): consists of electrically conductive material, Is part of an inductive resonant circuit of a controller, preferably by means of detuning the resonant circuit, in the area of at least one heating zone (17, 117) heated by electric radiant heating elements (16, 116) and arranged at least partially overlapping, characterized in that the sensor (21, 121) is essentially rectilinear and is loopless. Radiant heater according to claim 1, characterized in that the sensor (21, 121) has only one section running above the heating zone (17, 117), wherein it is preferably a straight electrical conductor. Radiant heater according to claim 1 or 2, characterized in that the sensor (21, 121) extends across a heating zone (17, 117) and / or the radiant heater (11, 111). Radiant heater according to one of the preceding claims, characterized in that the radiant heater is arranged in a metal plate (12, 112) which essentially supports it, and this metal plate (12, 112) is designed as a return conductor or second connection for the sensor (21, 121) The sensor (21, 121) is preferably electrically insulated from the metal plate on at least one end region (22), a first electrical connection (24, 124) leading directly to the sensor and a second electrical connection (28, 128) leads the metal plate (12, 112), which in turn is electrically connected to the sensor. Radiant heater according to one of the preceding claims, characterized in that the sensor (21, 121) runs centrally over the heating area (17, 117) of the radiant heater (11, 111), preferably in the case of a radiant heater (111) with a plurality of heating areas (117a, 117b) the sensor (121) extends over several heating areas, in particular all heating areas. Radiant heater according to one of the preceding claims, characterized in that the sensor (21, 121) is attached to the radiant heater (11, 111) in such a way that when the radiant heater is mounted it runs 0.1mm to 10mm below the hotplate, preferably the sensor being a Height adjustment has at least one of its ends. Radiant heater according to one of the preceding claims, characterized in that the sensor (21) is rigid, preferably tubular, and in particular is a metal tube which is electrically insulated from the outside. Radiant heater according to claim 7, characterized in that the sensor is combined with a rod regulator normally used in such a way that the metallic outer tube of the rod regulator forms the sensor (21). Radiant heater according to claim 7 or 8, characterized in that a normally used rod regulator with residual heat contact is attached to the radiant heater (11), the residual heat contact of the rod regulator not being required and the space thus freed up in the rod regulator as a connecting block (18) for the sensor connection is trained. Radiant heater according to one of claims 1 to 6, characterized in that the sensor (121) is designed to be elastic and / or flexible and is stretched over at least a portion of the heating region (117a, 117b), wherein it is preferably a wire, a strand or a Metal band is. Radiant heater according to one of the preceding claims, characterized by spring means (131) to compensate for a thermally induced change in length of the sensor (121) and / or to maintain the voltage of the sensor and / or to mount at least one end of the sensor, the spring force acting on the time / The temperature expansion limit of the sensor material and / or the cross-section of the sensor (121) is matched, the spring means preferably having a leaf spring (131). Radiant heater according to claim 11, characterized in that the sensor (121) is attached to the radiant heater (111) with at least one end by means of the spring means (131), in particular the spring means (131) opposite a metal plate (112) for holding the radiant heater (111) are electrically insulated. Radiant heater according to one of the preceding claims, characterized in that the sensor (21, 121) is scale-resistant. Radiant heater according to one of the preceding claims, characterized in that the material of the sensor (21, 121) has no Curie point. Radiant heater according to one of the preceding claims, characterized in that a noble metal temperature measuring resistor, preferably a PT100 or PT1000, is installed in a mounted, usually used rod regulator, the noble metal temperature measuring resistor being replaced by the ceramic part of the rod regulator and the outer tube of the rod regulator as Sensor (21) and as a holder for the noble metal temperature measuring resistor. Hob with several electric radiant heaters, characterized in that at least one of the radiant heaters (11, 111) is designed according to one of the preceding claims.

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