EP0250880B1 - Radiant heating element - Google Patents

Radiant heating element Download PDF

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Publication number
EP0250880B1
EP0250880B1 EP87107772A EP87107772A EP0250880B1 EP 0250880 B1 EP0250880 B1 EP 0250880B1 EP 87107772 A EP87107772 A EP 87107772A EP 87107772 A EP87107772 A EP 87107772A EP 0250880 B1 EP0250880 B1 EP 0250880B1
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EP
European Patent Office
Prior art keywords
radiant heater
heating
radiant
unit according
marginal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87107772A
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German (de)
French (fr)
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EP0250880A2 (en
EP0250880A3 (en
EP0250880B2 (en
Inventor
Gerhard Dipl.-Ing. Gössler
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EGO Elektro Geratebau GmbH
Original Assignee
EGO Elektro Gerate Blanc und Fischer GmbH
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Application filed by EGO Elektro Gerate Blanc und Fischer GmbH filed Critical EGO Elektro Gerate Blanc und Fischer GmbH
Priority to AT87107772T priority Critical patent/ATE69495T1/en
Publication of EP0250880A2 publication Critical patent/EP0250880A2/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
    • H05B3/74—Non-metallic plates, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits
    • H05B3/748—Resistive heating elements, i.e. heating elements exposed to the air, e.g. coil wire heater
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
    • H05B3/74—Non-metallic plates, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits
    • H05B3/746—Protection, e.g. overheat cutoff, hot plate indicator
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/04—Heating plates with overheat protection means
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/07—Heating plates with temperature control means

Definitions

  • the invention relates to a radiant heater according to the preamble of claim 1.
  • the food to be cooked must be gently heated to a predetermined temperature level for as short a time as possible, after which, when the power is reduced and controlled via a temperature switch or controlled by a power control device, cooking is continued without the need for a separate actuation of the electrical actuation process for the hotplate.
  • This automatic influencing of the heat output of the hotplate is so desirable that it does not automatically return to the state of the boiling phase after the one-time transition from the state of the boiling phase to the continued boiling phase, unless it has been switched off completely and by appropriate cooling again provided for the implementation of a next heating phase.
  • radiant heat in the visible wave range is emitted as quickly as possible, so that the cook can quickly recognize the operational readiness or the operating state of the hotplate from the visible glow of the associated radiant heater, and thus as far as possible high radiation density or heat output is quickly available.
  • a radiant heater in which a separately switchable radiant heater determines the edge heating and thus the fixed heating field size.
  • the inner area of the radiant heater lies within the edge heating, of which the radially outermost part of the circle does not belong to the edge heating formed exclusively by the outermost heating resistor. All sections of the radiant heating resistors are approximately evenly distributed over the entire heating field, without a particular distribution of the radiation density being recognizable.
  • the invention has for its object to provide a radiant heater of the type described, in which the time from switching on until reaching visible glow and thus also the heating time compared to previously known radiant heaters, which in particular have at least one exposed heating resistor, can be significantly reduced.
  • the parboiler heating is not switched off at the end of the parboiling phase, but is possibly reduced to a smaller difference in its radiation density compared to the area of the radiant heater within it.
  • a variable parboil circuit is created which, during the parboil phase, at least temporarily results in faster heat development in the edge area of the radiant heater or where the best contact between this vessel bottom and the heating plate is generally given due to the usual shape of the bottom of the cooking vessel.
  • the increased power difference during the heating phase, with which the edge heating is operated compared to the rest of the partial power can also be used to ensure that the edge heating described glows visibly in an extremely short time after switching on the hotplate and thus visually indicates the full operational readiness of this hotplate .
  • the described heat emission behavior of the parboiler heating which is continued to be used during the boiling phase, can e.g. can be achieved in a simple manner in that the parboiling edge heating is provided or switched over the entire parboiling phase with relatively increased power.
  • a particularly simple switchover from the parboiling phase to the continued boiling phase can be achieved, for example, by switching a partial output of the jet heater essentially as a function of time, preferably via a temperature switch with a high switching temperature difference or hysteresis.
  • This temperature switch only switches off at a relatively high temperature influencing its temperature sensor and only at a relatively low temperature which the radiant heater does not usually do during cooking, but only when it is full constant shutdown and after appropriate cooling, can achieve.
  • this behavioral characteristic of the temperature switch can also be achieved in that the heat coupling of the temperature sensor of the temperature switch to the radiant heater or the radiant heater is chosen to be very low such that the temperature sensor is only heated when the end of the heating phase is reached the switch-off temperature is heated and then can no longer cool down to its switch-on temperature due to low heat dissipation through appropriate insulation during continued cooking. This results in a time-dependent influencing of the parboiling phase using switching elements that respond exclusively to temperature influences.
  • a particularly simple embodiment of the subject matter of the invention is that at least a predetermined part of the jet heater, that is to say at least one heating resistor, is practically switched off by short-circuiting during the boiling phase.
  • a significant increase in the output in the outer region of the heating field can be achieved without any particular effort, this solution being suitable even for the simplest radiant heaters which have only a single radiant heating resistor, that is to say only a single electrical heating circuit.
  • At least one such inner part can be formed by a radiant heating resistor with a high positive temperature coefficient (PTC), the device influencing the transition from the boiling phase to the continued cooking phase then exclusively can be formed by the associated radiant heating resistor itself, since the PTC resistor brings about the desired reversal due to its characteristic behavior.
  • PTC positive temperature coefficient
  • a still further simplified and technically very economical solution to the problem on which the invention is based can also be achieved in that the parboiling edge heating is provided by a separate, in particular single-stranded, bifilar, i.e. Double back and forth heating circuit is formed, which is preferably always connected in parallel to the inner part of the jet heater. Because of its arrangement on the periphery of the heating field, this heating conductor can be subjected to a much higher load than the heating coil located within it, for example taking up the remaining part of the heating field, as a result of which a much faster visible glow of this area of the heating field and a shorter heating time can be achieved.
  • an advantageous solution to the object on which the invention is based is achieved in that the parboiler heating is connected to the carrier with less heat-conducting coupling than the inner part of the jet heater, so that the specific heat dissipation from the edge heating in the carrier is significantly less than that of the inner part of the jet heater and therefore the edge heating comes to a visible glow much faster after switching on.
  • This lower specific heat dissipation can be achieved by various, relatively simple measures, for example by a lower specific surface contact between the associated heating resistor and the support, by using a support material with a lower specific thermal conductivity in the area of the edge heating and by similar measures.
  • the parboiler control device can also be formed exclusively by the heat-conducting connection between the jet heater and the carrier, without using a separate control or regulating device, since only the characteristics of this heat-conducting connection are used to end the parboiling phase.
  • a particularly low specific thermal connection between the edge heating and the support can e.g. can be achieved in that longitudinal sections of the associated heating resistor are arranged essentially freely floating in a contact-free manner with respect to the carrier, that is to say they run in a contact-free or tensioned manner between suspension sections in the manner of suspension bridge sections.
  • the longitudinal sections of the heating resistor with a low thermal coupling to the support can also be created in that they lie in areas of the support which have different thermal conductivity due to the material of the support and are formed, for example, by a thermal insulation or insulation material which is suitable for the immediate mounting of the heating resistor is unsuitable, but has very good insulation properties.
  • Such an insulation material is used in radiant heaters, for example, as underbedding of a cup-shaped or disk-shaped insulation support body, which has lower thermal insulation values, but is suitable for the reliable determination of the heating resistance by direct embedding.
  • the relatively dimensionally stable insulation support body can be provided with openings in the area of the said longitudinal sections of the heating resistor, into which upward projections of the underbedding expediently protrude such that these projections pass through Completely completely fill breaks at least in plan view, wherein these projections can be set back at least partially in the vertical direction relative to the front side associated with the heating resistors and / or can be set at least partially in relation thereto.
  • the insulation support body can be, for example, a relatively solid molded body made of mineral fibers, made of a material such as is known, for example, under the trade name "Fiberfrax", while the underbedding is based on pyrogenic silica.
  • the parboil control device expediently has a temperature sensor that actuates the associated switch, which is preferably insulated with respect to the jet heater by means of an insulation layer, which in a simple manner without special additional insulation measures can be achieved that the temperature sensor is embedded in the already existing insulation material of the carrier, that is on the side facing away from the heating plate of the radiant heating resistor. If the temperature sensor is designed as an expansion rod sensor, it can simply be embedded in the insulation carrier by simply plugging it into the insulation carrier, and its switching head can lie outside the carrier.
  • This switch which operates in the manner of a temperature protection switch, can also be formed by a so-called Klixon thermostat, which interacts with a heat conducting rod, which transfers the heat from the sensing point to the temperature sensor in the switching head of the thermostat, for example formed by a bimetal sensor.
  • a radiant heater 1 according to the invention, which is intended to be arranged on the underside of a translucent heating plate 2 made of glass ceramic or the like, has a shell-shaped or cup-shaped support 4.
  • the carrier 4 consists essentially of a one-part or multi-part inner shell 5 made of at least one insulation material and a relatively thin-walled outer shell 6, which serves to protect and mount the inner shell 5, which preferably consists of sheet steel.
  • the inner shell 5 carries on its substantially flat or parallel to the heating plate 2 floor a radiant heater 7 to be operated by electric current in the form of at least one encapsulated heating resistor 8, but it is conceivable that at least part of the power of the radiant heater 1 also with a encapsulated radiant heater, i.e. a bulb lamp, such as a halogen lamp, can be operated.
  • the radiant heater has only unencapsulated heating resistors.
  • the heating resistor 8 is laid in a double spiral approximately in such a way about the central axis of the radiant heater 1 that its two connection ends 14 lie on the periphery of the heating field 10 which is essentially delimited by the outermost, approximately annularly closed spiral winding.
  • a predetermined number of outer turns of the heating resistor 8, namely about half of all turns or about three spiral turns in the exemplary embodiment shown, are provided as the heating-up edge heating 9 for operation with a relatively increased radiation density during the heating-up phase, while the rest lie within this heating edge 9 Windings of the same heating resistor form a remaining partial power 11, which can be operated in a variable power gradient with respect to the edge heating 9.
  • the entire jet heater 7, that is to say the only heating resistor 8 forming this, is operated during the entire heating operation by means of an adjustable control device or, for example, a clocking power control device, with the jet heater 7 being connected to the mains current with the interposition thereof.
  • an adjustable control device or, for example, a clocking power control device there is a temperature sensor 16 crossing the heating field 10 in the space between the radiant heater 7 and the heating plate 2, which in the case of using a control device 12 for the operation of the Jet heater 7 can influence this or can be assigned to a temperature limiter 15, the switching head of which is arranged directly on the outside of the carrier 4 penetrated by the temperature sensor 16.
  • the temperature sensor 17, which can be an expansion rod sensor with an outer tube and an inner rod arranged therein with different expansion coefficients, or a heat conducting rod which supplies the heat from the sensing point to the switching head of the control device 13 below the switching head of the temperature limiter 15 on the outside of the carrier 4 also parallel to the heating plate 2, but below the bottom surface of the inner shell 5 receiving the radiant heater 7 and above its underside, i.e.
  • this temperature sensor 17 can be shorter than half the width of the heating field 10 such that it essentially only on one side of its central axis in the area of the associated turns of the edge heating 9 l weighs.
  • a cut-off switch 18 Arranged in the switching head of the control device 13 designed as a cut-off switch 18 in the form of, for example, a snap switch, which is not directly connected to the power supply for the radiant heater 7, is arranged in a short-circuit circuit of a short-circuit for the partial power 11, that is to say exclusively via its two connecting poles two points at a distance from each other of the heating resistor 8 so electrically connected that when the parboiler 11 is closed, the longitudinal section of the heating resistor 8 belonging to the partial power 11 and occupying the inner zone of the heating field 10 is essentially taken out of operation by short-circuiting.
  • the remaining section of the heating resistor 8 associated with the parboiler heating and operating essentially up to the periphery of the heating field 10 is operated during the closed short-circuit circuit 19 with a relatively substantially increased radiation density and, after being switched on, is heated up very quickly so that the heating plate 2 a visible glow can be perceived.
  • the heating switch 18 opens, so that now also the longitudinal section of the heating resistor 8 belonging to the partial power 11 goes into full power operation and thus the difference in radiation density between the area of the heating edge heating 9 and that of the partial power 11 is at least reduced.
  • increased power should be available for as long as possible during the boiling process, without switching back to the increased power again during continued cooking and after the temperature monitor forming the control device 13 has responded.
  • the shortening of the boil-up time to be achieved by the design according to the invention also results from the fact that the cooking vessel base 3 of cooking vessels is usually curved in such a way that the cooking vessel base 3 has the most direct contact with the heating plate 2 in the region of its outer edge and therefore there is a particular one faster heat transfer is possible.
  • arrows, the length of which represent the radiation density indicate that an operating arrangement is provided in the subject matter of the invention in such a way that the power density is greatest in this edge region in the boiling phase. In the continued cooking phase, either this external power density in the edge area 9 can be reduced, the power density in the area of the partial power 11 can be increased, or both processes can be carried out simultaneously.
  • the switching hysteresis of the control device 13 is chosen so large that it no longer switches back to the short-circuit position, that is to say in the closed position of the parboiler switch 18, before the radiant heater 1 has almost completely cooled.
  • this longitudinal section can also be formed by a heating conductor with a high positive temperature coefficient, which consists, for example, of molybdenum disilicide.
  • a heating conductor with a high positive temperature coefficient which consists, for example, of molybdenum disilicide.
  • the carrier 4 is stretched with the end face of the edge of the shell of the inner shell 5 under pressure over the entire surface against the inside or underside of the heating plate, so that the inner circumference of this contact edge essentially coincides with the periphery or outer boundary of the heating field 10.
  • the heating resistor 8 can be immovably fixed to the inner shell 5 by at least partially embedding its coils in the insulating material.
  • the radiant heater can also be round, rectangular or square, deviating from the circular shape, instead of being circular, the heating resistor then expediently following this outer contour in its spiral shape.
  • the radiant heater 1 a has as the parboiling edge heater 9 a one in only one operation, that is, only in a single-strand loop or bifilar external heating resistor made of particularly thin, heavy-duty resistance wire, i.e. of a resistance wire that is thinner and is more resilient or loaded than the heating resistor belonging to the partial power 11.
  • the radiant heater of this radiant heater 1 is basically of two-circuit design, but the two heating circuits are connected in parallel or in series, which is why they are always switched on and off simultaneously.
  • the inner shell 5a consists of two superimposed supporting bodies 20, 21 of different insulating materials and thicknesses, the lower, panel-shaped supporting body 20 consisting of a powdery pressed mass, being relatively pressure-elastic, a greater thickness than the molded body 21 lying thereon over the entire surface has and above all has a thermal insulation value which is significantly higher than that of the support body 21.
  • the disk-shaped support body 21 for example, is a relatively dimensionally stable molded body made of pressed mineral fibers, on which the heating resistors are held by embedding in places. This support body 21 has on the upper side upwards about its remaining thickness, approximately radial to the central axis of the radiant heater 1 a and integrally formed with the rest of the support body 21 webs.
  • the webs lying only in the radially outer region of the heating field are each formed between depressions 23, which extend from the periphery of the heating field only over part of the turns of the heating resistors.
  • the windings lying radially inside the depressions 23, that is to say in the central region, are therefore in direct contact with the inner shell 5a.
  • these turns are held by embedding exclusively on the webs 22, while according to FIG. 5 they float freely in the area of the depressions, that is to say opposite span or bridge the inner shell 5a without contact or only lie weakly.
  • the distance of the longitudinal sections of the heating resistors bridging the depressions parallel to their bottom surfaces from these bottom surfaces can be smaller than the outside diameter of these heating resistors, in particular about half as large, while the heating resistors are embedded in the webs 22 by about half their outside diameter.
  • the distance between adjacent webs can be approximately twice their width.
  • openings or openings 23b which are continuous over the thickness of the support body 21b can also be provided, which are at least partially filled by projections 24 of the lower support body 20b.
  • the projections 24 extend slightly above the upper sides of the webs 22b, but are provided with channel-shaped receiving grooves 25 in the region of each longitudinal section crossing them, the bottom surfaces of which can be slightly lower than the upper side of the webs 21b.
  • the depth of the receiving grooves 25, relative to which the associated longitudinal sections of the heating resistors can be provided in a contact-free manner or only loosely but without embedded, is expediently so great that the adjacent receiving grooves 25 separating webs of the support body 21b only extend approximately to the middle of the outer diameter of these longitudinal sections.
  • the heat dissipation from the above-mentioned longitudinal sections of the radiant heaters lying between the webs 21 into the inner shell 5b is particularly low, so that these longitudinal sections very quickly come to a visible glow after being switched on from the cold state.
  • control device 13 can be similar to that according to DE-OS 32 47 028 or that according to EP-A- 01 14 307, to which reference is made for further details.
  • the parboiler heating is in the same space as that of the rest of the jet heater 7, which is enclosed by the carrier 4 and the heating plate 2, and is not separated from it in a ring shape by an intermediate web of the carrier.
  • the invention results in a higher specific power in the outdoor area, which may be as high as it could not be expected from the heating resistor and / or the glass ceramic plate in continuous operation. Due to its mostly temporary effect and the higher power consumption in this area, especially during the parboiling phase, it does not trigger any harmful effects.
  • a higher specific power could also be provided outdoors. It mainly has an effect during the heating-up time, in that the outer heating conductor glows faster, so that the desired optical effects are triggered and heat transfer to the cooking vessel begins earlier. During the continued cooking phase, this power distribution, which is advantageously maintained without switching, hardly plays out, at least not negatively, because the total power then e.g. is reduced by cyclical switching on and off of the total power. It has been shown that a higher specific load on the edge area and in particular on the outer heating conductor winding does not play an important role in their service life, since these do not burn out even with some overload.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Electric Stoves And Ranges (AREA)
  • Resistance Heating (AREA)
  • Power Steering Mechanism (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
  • Control Of Resistance Heating (AREA)

Abstract

In a radiant heater unit (1) for heating through a hotplate (2), the periphery of the heating field is formed by an initial cooking marginal heating system (9), which is e.g. operated by a short-circuit connection (19), so that it passes much more rapidly from the cold state into the visible glowing state and also in the marginal region use is made of the faster heat transfer there to the bottom (3) of the cooking utensil. The increased radiant power density can also be obtained by other measures, namely by modified insulating conditions in the vicinity of the marginal heating system, by using a PTC resistor in the vicinity of the inner partial power system and similar measures.

Description

Die Erfindung betrifft einen Strahlheizkörper nach dem Oberbegriff des Patentanspruches 1.The invention relates to a radiant heater according to the preamble of claim 1.

Bei zahlreichen Kochprozessen ist es erwünscht, eine möglichst kurze Ankochzeit zu erreichen, d.h. am Anfang des Kochprozesses das Kochgut während möglichst kurzer Zeit schonend auf ein vorbestimmtes Temperaturniveau anzuheizen, wonach bei zurückgefahrener Leistung und geregelt über einen Temperaturschalter oder gesteuert über ein Leistungssteuergerät fortgekocht wird, ohne daß hierfür eine gesonderte Betätigung des elektrischen Betätigungsorganges für die Kochstelle erforderlich sein soll. Diese automatische Beeinflussung der Wärmeabgabe der Kochstelle ist dabei so erwünscht, daß sie nach dem einmaligen Übergang vom Zustand der Ankochphase in die Fortkochphase nicht mehr von selbst in den Zustand der Ankochphase zurückkehrt, es sei denn, sie ist ganz abgeschaltet worden und durch entsprechende Abkühlung wieder für die Durchführung einer nächsten Ankochphase bereitgestellt.With numerous cooking processes, it is desirable to achieve the shortest possible heating time, i.e. At the beginning of the cooking process, the food to be cooked must be gently heated to a predetermined temperature level for as short a time as possible, after which, when the power is reduced and controlled via a temperature switch or controlled by a power control device, cooking is continued without the need for a separate actuation of the electrical actuation process for the hotplate. This automatic influencing of the heat output of the hotplate is so desirable that it does not automatically return to the state of the boiling phase after the one-time transition from the state of the boiling phase to the continued boiling phase, unless it has been switched off completely and by appropriate cooling again provided for the implementation of a next heating phase.

Bei Strahlheizkörpern ist es darüber hinaus erwünscht, daß nach dem Einschalten einer Kochstelle nach möglichst kurzer Zeit Strahlungswärme im sichtbaren Wellenbereich abgegeben wird, damit die kochende Person möglichst schnell anhand des sichtbaren Glühens des zugehörigen Strahlheizers die Betriebsbereitschaft bzw. den Betriebszustand der Kochstelle erkennt und damit möglichst schnell eine hohe Strahlungsdichte bzw. Wärmeleistung zur Verfügung steht.In the case of radiant heaters, it is also desirable that after switching on a hotplate, radiant heat in the visible wave range is emitted as quickly as possible, so that the cook can quickly recognize the operational readiness or the operating state of the hotplate from the visible glow of the associated radiant heater, and thus as far as possible high radiation density or heat output is quickly available.

Es wurde bereits versucht, dieses thermische und optische Verhalten eines Strahlheizkörpers dadurch zu erreichen, daß an der Peripherie des Heizfeldes ein gesonderter Strahlheizwiderstand vorgesehen ist, der während der Ankoch- bzw. Anheizphase zugeschaltet wird und nach der Ankochphase abgeschaltet bleibt. Einen solchen äußeren, gesondert zuschaltbaren Heizwiderstand gibt es auch für solche Kochstellen, welche zwischen zwei festen Heizfeldgrößen umschaltbar sind, um sie wahlweise auf Kochgefässe unterschiedlicher Grundriß-Größe umschalten zu können. Mit solchen Anordnungen können zwar zum Teil recht gute Ergebnisse erzielt werden, jedoch führt das Abschalten des während der Ankochphase zugeschalteten Heizwiderstandes während des Fortkochens zu einer relativ ungleichmäßigen spezifischen Wärmebeaufschlagung des Kochgefäßbodens. Außerdem werden dafür Leistungssteuergeräte mit Zusatzschaltern benötigt.Attempts have already been made to achieve this thermal and optical behavior of a radiant heater by providing a separate radiant heating resistor at the periphery of the heating field, which is switched on during the heating or heating phase and remains switched off after the heating phase. Such an external, separately switchable heating resistor is also available for those hotplates which can be switched between two fixed heating field sizes in order to be able to selectively switch them to cooking vessels of different floor plan sizes. With such arrangements, quite good results can be achieved in some cases, but switching off the heating resistor which is switched on during the boiling phase leads to a relatively uneven specific heat application to the bottom of the cooking vessel during cooking. Power control units with additional switches are also required for this.

Nach der GB-A-2 115 259 ist ein Strahlheizkörper bekannt, bei welchem ein gesondert schaltbarer Strahlheizwiderstand die Randbeheizung und damit die feste Heizfeldgröße bestimmt. Innerhalb der Randbeheizung liegt der innere Bereich des Strahlheizers, von dem auch die radial äußersten Teilkreisabschnitte nicht zu der ausschließlich durch den äußersten Heizwiderstand gebildeten Randbeheizung gehören. Sämtliche Abschnitte der Strahlheizwiderstände sind etwa gleichmäßig über das gesamte Heizfeld verteilt, ohne daß eine besondere Verteilung der Strahlungsdichte erkennbar wäre.According to GB-A-2 115 259 a radiant heater is known, in which a separately switchable radiant heater determines the edge heating and thus the fixed heating field size. The inner area of the radiant heater lies within the edge heating, of which the radially outermost part of the circle does not belong to the edge heating formed exclusively by the outermost heating resistor. All sections of the radiant heating resistors are approximately evenly distributed over the entire heating field, without a particular distribution of the radiation density being recognizable.

Der Erfindung liegt die Aufgabe zugrunde, einen Strahlheizkörper der beschriebenen Art zu schaffen, bei welchm die Zeit vom Einschalten bis zum Erreichen eines sichtbaren Glühens und damit auch die Ankochzeit gegenüber bisher bekannten Strahlheizkörpern, die insbesondere mindestens einen freiliegenden Heizwiderstand aufweisen, merklich verkürzt werden kann.The invention has for its object to provide a radiant heater of the type described, in which the time from switching on until reaching visible glow and thus also the heating time compared to previously known radiant heaters, which in particular have at least one exposed heating resistor, can be significantly reduced.

Diese Aufgabe wird bei einem Strahlheizkörper der eingangs beschriebenen Art gemäß der Erfindung durch den Patentanspruch 1 gelöst.This object is achieved in a radiant heater of the type described above according to the invention by claim 1.

Zweckmäßig wird die Ankoch-Randbeheizung am Ende der Ankochphase nicht abgeschaltet, sondern ggf. auf einen geringeren Unterschied ihrer Strahlungsdichte gegenüber dem innerhalb ihr liegenden Bereich des Strahlheizers zurückgefahren. Es wird eine variable Ankoch-Schaltung geschaffen, die während der Ankochphase zumindest vorübergehend eine schnellere Wärmeentwicklung im Randbereich des Strahlheizkörpers bzw. dort ergibt, wo in der Regel aufgrund der üblichen Bodenform von Kochgefässen der beste Kontakt zwischen diesem Gefäßboden und der Heizplatte gegeben ist. Der während der Ankochphase erhöhte positive Leistungsunterschied, mit welchem die Randbeheizung gegenüber der übrigen Teilleistung gefahren wird, kann auch dafür herangezogen werden, daß die so beschriebene Randbeheizung nach dem Einschalten der Kochstelle in äußerst kurzer Zeit sichtbar glüht und damit optisch die volle Betriebsbereitschaft dieser Kochstelle anzeigt.Advantageously, the parboiler heating is not switched off at the end of the parboiling phase, but is possibly reduced to a smaller difference in its radiation density compared to the area of the radiant heater within it. A variable parboil circuit is created which, during the parboil phase, at least temporarily results in faster heat development in the edge area of the radiant heater or where the best contact between this vessel bottom and the heating plate is generally given due to the usual shape of the bottom of the cooking vessel. The increased power difference during the heating phase, with which the edge heating is operated compared to the rest of the partial power, can also be used to ensure that the edge heating described glows visibly in an extremely short time after switching on the hotplate and thus visually indicates the full operational readiness of this hotplate .

Das beschriebene Wärmeabgabe-Verhalten der Ankoch-Randbeheizung, die gleichzeitig in der Fortkochphase weiter betrieben wird, kann z.B. auf einfache Weise dadurch erreicht werden, daß die Ankoch-Randbeheizung im wesentlichen über die gesamte Ankochphase mit relativ erhöhter Leistung vorgesehen bzw. geschaltet ist.The described heat emission behavior of the parboiler heating, which is continued to be used during the boiling phase, can e.g. can be achieved in a simple manner in that the parboiling edge heating is provided or switched over the entire parboiling phase with relatively increased power.

Eine besonders einfache Umschaltung von der Ankochphase in die Fortkochphase kann z.B. dadurch erreicht werden, daß eine Teilleistung des Strahlheizers im wesentlichen zeitabhängig, vorzugsweise über einen Temperaturschalter mit hoher Schalttemperaturdifferenz bzw. -Hysterese geschaltet wird. Dieser Temperaturschalter schaltet erst bei einer relativ hohen, seinen Temperaturfühler beeinflussenden Temperatur ab und erst bei einer relativ so niedrigen Temperatur wieder ein, wie sie der Strahlheizkörper während des Fortkochens üblicherweise nicht, sondern nur durch vollständiges Abschalten und nach entsprechendem Abkühlen, erreichen kann. Statt dessen oder zusätzlich hierzu kann diese Verhaltenscharakteristik des Temperaturschalters auch dadurch erreicht werden, daß die Wärme-Ankoppelung des Temperaturfühlers des Temperaturschalters an den Strahlheizer bzw. den Strahlheizkörper sehr gering so gewählt wird, daß der Temperaturfühler erst bei Erreichen des Endes der Ankochphase durch Wärmeleitung auf die Abschalttemperatur erwärmt ist und dann infolge geringer Wärmeableitung durch entsprechende Isolierung während des Fortkochens nicht mehr auf seine Einschalttemperatur abkühlen kann. Es ergibt sich also eine zeitabhängige Beeinflussung der Ankochphase unter Verwendung ausschließlich auf Temperatureinflüsse ansprechender Schaltorgane.A particularly simple switchover from the parboiling phase to the continued boiling phase can be achieved, for example, by switching a partial output of the jet heater essentially as a function of time, preferably via a temperature switch with a high switching temperature difference or hysteresis. This temperature switch only switches off at a relatively high temperature influencing its temperature sensor and only at a relatively low temperature which the radiant heater does not usually do during cooking, but only when it is full constant shutdown and after appropriate cooling, can achieve. Instead of or in addition to this, this behavioral characteristic of the temperature switch can also be achieved in that the heat coupling of the temperature sensor of the temperature switch to the radiant heater or the radiant heater is chosen to be very low such that the temperature sensor is only heated when the end of the heating phase is reached the switch-off temperature is heated and then can no longer cool down to its switch-on temperature due to low heat dissipation through appropriate insulation during continued cooking. This results in a time-dependent influencing of the parboiling phase using switching elements that respond exclusively to temperature influences.

Eine besonders einfache Ausführungsform des Erfindungsgegenstandes liegt darin, daß während der Ankochphase mindestens ein vorbestimmter Teil des Strahlheizers, also mindestens eines Heizwiderstandes durch Kurzschließen praktisch abgeschaltet wird. Dadurch kann eine wesentliche Erhöhung der Leistung im Außenbereich des Heizfeldes ohne besonderen Aufwand erreicht werden, wobei diese Lösung selbst für solche einfachsten Strahlheizkörper geeignet ist, welche nur einen einzigen Strahlheizwiderstand, also nur einen einzigen elektrischen Heizkreis aufweisen.A particularly simple embodiment of the subject matter of the invention is that at least a predetermined part of the jet heater, that is to say at least one heating resistor, is practically switched off by short-circuiting during the boiling phase. As a result, a significant increase in the output in the outer region of the heating field can be achieved without any particular effort, this solution being suitable even for the simplest radiant heaters which have only a single radiant heating resistor, that is to say only a single electrical heating circuit.

Insbesondere anstatt einer solchen Kurzschlußschaltung für mindestens einen innerhalb der Peripherie liegenden Teil des Strahlheizers kann mindestens ein solcher innerer Teil durch einen Strahl- heizwiderstand mit hohem positivem Temperaturkoeffizienten (PTC) gebildet sein, wobei dann die den Übergang von der Ankochphase in die Fortkochphase beeinflußende Einrichtung ausschließlich durch den zugehörigen Strahlheizwiderstand selbst gebildet sein kann, da der PTC-Widerstand aufgrund seines charakteristischen Verhaltens die gewünschte Umsteuerung bewirkt.In particular, instead of such a short circuit for at least one part of the radiant heater located within the periphery, at least one such inner part can be formed by a radiant heating resistor with a high positive temperature coefficient (PTC), the device influencing the transition from the boiling phase to the continued cooking phase then exclusively can be formed by the associated radiant heating resistor itself, since the PTC resistor brings about the desired reversal due to its characteristic behavior.

Eine noch weiter vereinfachte und fertigungstechnisch sehr günstige Lösung der der Erfindung zugrundeliegenden Aufgabe kann auch dadurch erreicht werden, daß die Ankoch-Randbeheizung durch einen gesonderten, insbesondere einstrangig sich nur über höchstens 360° erstreckenden, ggf. bifilaren, d.h. doppelt hin- und zurückgeführten Heizkreis gebildet ist, der vorzugsweise stets zum inneren Teil des Strahlheizers parallel geschaltet ist. Wegen seiner Anordnung an der Peripherie des Heizfeldes kann dieser Heizleiter wesentlich höher belastet werden als die innerhalb ihm liegende, beispielsweise den restlichen Teil des Heizfeldes einnehmende Heizwendel, wodurch ein wesentlich schnelleres sichtbares Glühen dieses Bereiches des Heizfeldes sowie eine kürzere Ankochzeit zu erreichen sind.A still further simplified and technically very economical solution to the problem on which the invention is based can also be achieved in that the parboiling edge heating is provided by a separate, in particular single-stranded, bifilar, i.e. Double back and forth heating circuit is formed, which is preferably always connected in parallel to the inner part of the jet heater. Because of its arrangement on the periphery of the heating field, this heating conductor can be subjected to a much higher load than the heating coil located within it, for example taking up the remaining part of the heating field, as a result of which a much faster visible glow of this area of the heating field and a shorter heating time can be achieved.

Zusätzlich zu den beschriebenen Maßnahmen, aber auch statt dessen, ist eine vorteilhafte Lösung der der Erfindung zugrundeliegenden Aufgabe dadurch zu erreichen, daß die Ankoch-Randbeheizung mit geringerer Wärmeleit-Ankoppelung als der innere Teil des Strahlheizers mit dem Träger verbunden ist, so daß also die spezifische Wärmeableitung von der Randbeheizung in den Träger wesentlich geringer als diejenige des inneren Teiles des Strahlheizers ist und daher die Randbeheizung nach dem Einschalten wesentlich schneller zum sichtbaren Glühen kommt. Diese geringere spezifische Wärmeableitung kann durch verschiedene, relativ einfache Maßnahmen, beispielsweise durch eine geringere spezifische Flächenberührung zwischen dem zugehörigen Heizwiderstand und dem Träger, durch Verwendung eines Tragwerkstoffes mit geringerer spezifischer Wärmeleitfähigkeit im Bereich der Randbeheizung sowie durch ähnliche Maßnahmen erreicht werden. In diesem Fall kann ebenfalls ohne Verwendung einer gesonderten Steuer-oder Regeleinrichtung die Ankoch-Steuereinrichtung ausschließlich durch die Wärmeleitverbindung zwischen dem Strahlheizer und dem Träger gebildet sein, da zur Beendigung der Ankochphase ausschließlich die Charakteristika dieser Wärmeleitverbindung herangezogen werden.In addition to the measures described, but also instead, an advantageous solution to the object on which the invention is based is achieved in that the parboiler heating is connected to the carrier with less heat-conducting coupling than the inner part of the jet heater, so that the specific heat dissipation from the edge heating in the carrier is significantly less than that of the inner part of the jet heater and therefore the edge heating comes to a visible glow much faster after switching on. This lower specific heat dissipation can be achieved by various, relatively simple measures, for example by a lower specific surface contact between the associated heating resistor and the support, by using a support material with a lower specific thermal conductivity in the area of the edge heating and by similar measures. In this case, the parboiler control device can also be formed exclusively by the heat-conducting connection between the jet heater and the carrier, without using a separate control or regulating device, since only the characteristics of this heat-conducting connection are used to end the parboiling phase.

Eine besonders geringe spezifische Wärmeleitverbindung zwischen der Randbeheizung und dem Träger kann z.B. dadurch erreicht werden, daß Längsabschnitte des zugehörigen Heizwiderstandes im wesentlichen frei schwebend berührungsfrei gegenüber dem Träger angeordnet sind, also nach Art von Hängebrücken-Abschnitten zwischen Aufhängungsabschnitten berührungsfrei bzw. gespannt verlaufen.A particularly low specific thermal connection between the edge heating and the support can e.g. can be achieved in that longitudinal sections of the associated heating resistor are arranged essentially freely floating in a contact-free manner with respect to the carrier, that is to say they run in a contact-free or tensioned manner between suspension sections in the manner of suspension bridge sections.

Die in geringer Wärmeleit-Ankoppelung zum Träger stehenden Längsabschnitte des Heizwiderstandes können aber auch dadurch geschaffen werden, daß sie in Bereichen des Trägers liegen, die von dessen Werkstoff her unterschiedliche Wärmeleitfähigkeit aufweisen und beispielsweise durch einen Wärmedämm- bzw. Isolationswerkstoff gebildet sind, der zwar für die unmittelbare Halterung des Heizwiderstandes ungeeignet ist, jedoch sehr gute Isolationseigenschaften aufweist.However, the longitudinal sections of the heating resistor with a low thermal coupling to the support can also be created in that they lie in areas of the support which have different thermal conductivity due to the material of the support and are formed, for example, by a thermal insulation or insulation material which is suitable for the immediate mounting of the heating resistor is unsuitable, but has very good insulation properties.

Ein solcher Isolationswerkstoff wird bei Strahlheizkörpern beispielsweise als Unterbettung eines napf- oder scheibenförmigen Isolations- Tragkörpers verwendet, der zwar niedrigere thermische Dämmwerte hat, jedoch für die sichere Festlegung des Heizwiderstandes durch unmittelbare Einbettung geeignet ist. In diesem Fall kann der relativ formfeste Isolations-Tragkörper im Bereich der genannten Längsabschnitte des Heizwiderstandes mit Durchbrüchen versehen sein, in welche nach oben gerichtete Vorsprünge der Unterbettung zweckmäßig derart ragen, daß diese Vorsprünge die Durchbrüche zumindest in Draufsicht im wesentlichen vollständig ausfüllen, wobei diese Vorsprünge wenigstens teilweise in Höhenrichtung gegenüber der den Heizwiderständen zugehörigen Vorderseite zurückversetzt und/oder wenigstens teilweise demgegenüber vorversetzt sein können. Der Isolations-Tragkörper kann beispielsweise ein relativ fester Formkörper aus mineralischen Fasern, aus einem Werkstoff sein, wie er z.B. unter dem Handelsnamen "Fiberfrax" bekannt ist, während die Unterbettung auf der Basis von pyrogener Kieselsäure aufgebaut ist.Such an insulation material is used in radiant heaters, for example, as underbedding of a cup-shaped or disk-shaped insulation support body, which has lower thermal insulation values, but is suitable for the reliable determination of the heating resistance by direct embedding. In this case, the relatively dimensionally stable insulation support body can be provided with openings in the area of the said longitudinal sections of the heating resistor, into which upward projections of the underbedding expediently protrude such that these projections pass through Completely completely fill breaks at least in plan view, wherein these projections can be set back at least partially in the vertical direction relative to the front side associated with the heating resistors and / or can be set at least partially in relation thereto. The insulation support body can be, for example, a relatively solid molded body made of mineral fibers, made of a material such as is known, for example, under the trade name "Fiberfrax", while the underbedding is based on pyrogenic silica.

Sofern zur Umschaltung von der Ankochphase zur Fortkochphase eine Unterbrechung eines elektrischen Kreises herangezogen wird, weist die Ankoch-Regeleinrichtung zweckmäßig einen den zugehörigen Schalter betätigenden Temperaturfühler auf, der vorzugsweise über eine Isolationsschicht gegenüber dem Strahlheizer wärmegedämmt ist, was ohne besondere zusätzliche Isolationsmaßnahmen auf einfache Weise dadurch erreicht werden kann, daß der Temperaturfühler in den ohnehin vorhandenen Isolationswerkstoff des Trägers eingebettet ist, also auf der von der Heizplatte abgekehrten Seite des Strahlheizwiderstandes liegt. Ist der Temperaturfühler als Dehnstabfühler ausgebildet, so kann er lediglich durch Einstekken in den Isolationsträger auf einfache Weise in diesen eingebettet werden, und sein Schaltkopf kann außerhalb des Trägers liegen. Dieser nach Art eines Temperaturschutzschalters arbeitende Schalter kann aber auch durch einen sogenannten Klixon-Thermostaten gebildet sein, der mit einem Wärmeleitstab zusammenwirkt, welcher die Wärme von der Fühlstelle zum beispielsweise durch einen Bimetallfühler gebildeten Temperaturfühler im Schaltkopf des Thermostaten überträgt.If an electrical circuit is interrupted to switch from the boiling phase to the boiling phase, the parboil control device expediently has a temperature sensor that actuates the associated switch, which is preferably insulated with respect to the jet heater by means of an insulation layer, which in a simple manner without special additional insulation measures can be achieved that the temperature sensor is embedded in the already existing insulation material of the carrier, that is on the side facing away from the heating plate of the radiant heating resistor. If the temperature sensor is designed as an expansion rod sensor, it can simply be embedded in the insulation carrier by simply plugging it into the insulation carrier, and its switching head can lie outside the carrier. This switch, which operates in the manner of a temperature protection switch, can also be formed by a so-called Klixon thermostat, which interacts with a heat conducting rod, which transfers the heat from the sensing point to the temperature sensor in the switching head of the thermostat, for example formed by a bimetal sensor.

Diese und weitere Merkmale von bevorzugten Weiterbildungen der Erfindung gehen auch aus der Beschreibung und den Zeichnungen hervor, wobei die einzelnen Merkmale jeweils für sich allein oder zu mehreren in Form von Unterkombinationen bei einer Ausführungsform der Erfindung und auf anderen Gebieten verwirklicht sein und vorteilhafte sowie für sich schutzfähige Ausführungen darstellen können, für die hier Schutz beansprucht wird. Ausführungsbeispiele der Erfindung sind in den Zeichnungen dargestellt und werden im folgenden näher erläutert. In den Zeichnungen zeigen:

  • Fig. 1 einen erfindungsgemäßen Strahlheizkörper im Querschnitt und in vereinfachter Darstellung,
  • Fig. 2 den Strahlheizkörper gemäß Fig. 1 in Draufsicht,
  • Fig. 3 eine schematische Darstellung der Verteilung der Strahl-Leistungsdichte in der Ankochphase,
  • Fig. 4 eine weitere Ausführungsform eines Strahlheizkörpers in einer Darstellung entsprechend Fig. 2,
  • Fig. 5 einen Schnitt nach der Linie V-V in Fig. 4 in abgewickelter Darstellung,
  • Fig. 6 eine weitere Ausführungsform in einer Darstellung entsprechend Fig. 5,
  • Fig. 7 einen Schnitt nach der Linie VII-VII in Fig. 6.
These and further features of preferred developments of the invention also emerge from the description and the drawings, the individual features being realized individually and in groups in the form of subcombinations in one embodiment of the invention and in other fields, and advantageous and for themselves Protectable designs for which protection is claimed here. Embodiments of the invention are shown in the drawings and are explained in more detail below. The drawings show:
  • 1 shows a radiant heater according to the invention in cross section and in a simplified representation,
  • 2 shows the radiant heater according to FIG. 1 in plan view,
  • 3 shows a schematic representation of the distribution of the beam power density in the parboiling phase,
  • 4 shows a further embodiment of a radiant heater in a representation corresponding to FIG. 2,
  • 5 shows a section along the line VV in FIG. 4 in a developed representation,
  • 6 shows a further embodiment in a representation corresponding to FIG. 5,
  • 7 is a section along the line VII-VII in Fig. 6th

Wie die Fig. 1 und 2 zeigen, weist ein erfindungsgemäßer Strahlheizkörper 1, der zur Anordnung an der Unterseite einer aus Glaskeramik oder dgl. bestehenden, transluzenten Heizplatte 2 bestimmt ist, einen schalen- bzw. napfförmigen Träger 4 auf. Der Träger 4 besteht im wesentlichen aus einer ein- oder mehrteiligen Innenschale 5 aus mindestens einem Isolationswerkstoff und einer relativ dünnwandigen, dem Schutz und der Fassung der Innenschale 5 dienenden Außenschale 6, die bevorzugt aus Stahlblech besteht. Die Innenschale 5 trägt auf ihrem im wesentlichen ebenen bzw. zur Heizplatte 2 parallelen Boden einen durch elektrischen Strom zu betreibenden Strahlheizer 7 in Form mindestens eines unverkapselten Heizwiderstandes 8, wobei es jedoch denkbar ist, daß zumindest ein Teil der Leistung des Strahlheizkörpers 1 auch mit einem verkapselten Strahlheizkörper, also einer Kolbenlampe, wie einem Halogenstrahler, betrieben werden kann. Die bevorzugte Anordnung liegt jedoch darin, daß der Strahlheizkörper ausschließlich unverkapselte Heizwiderstände aufweist.1 and 2 show, a radiant heater 1 according to the invention, which is intended to be arranged on the underside of a translucent heating plate 2 made of glass ceramic or the like, has a shell-shaped or cup-shaped support 4. The carrier 4 consists essentially of a one-part or multi-part inner shell 5 made of at least one insulation material and a relatively thin-walled outer shell 6, which serves to protect and mount the inner shell 5, which preferably consists of sheet steel. The inner shell 5 carries on its substantially flat or parallel to the heating plate 2 floor a radiant heater 7 to be operated by electric current in the form of at least one encapsulated heating resistor 8, but it is conceivable that at least part of the power of the radiant heater 1 also with a encapsulated radiant heater, i.e. a bulb lamp, such as a halogen lamp, can be operated. However, the preferred arrangement is that the radiant heater has only unencapsulated heating resistors.

Der Heizwiderstand 8 ist in einer Doppelspirale etwa derart um die Mittelachse des Strahlheizkörpers 1 verlegt, daß seine beiden Anschlußenden 14 an der Peripherie des im wesentlichen durch die äußerste, annähernd ringförmig geschlossene Spiralwindung begrenzten Heizfeldes 10 liegen. Eine vorbestimmte Anzahl äußerer Windungen des Heizwiderstandes 8, nämlich im dargestellten Ausführungsbeispiel etwa die Hälfte aller Windungen bzw. etwa drei Spiralwindungen, sind als Ankoch-Randbeheizung 9 zum Betrieb mit relativ erhöhter Strahlungsdichte während der Ankochphase vorgesehen, während die übrigen, innerhalb dieser Randbeheizung 9 liegenden Windungen desselben Heizwiderstandes eine restliche Teilleistung 11 bilden, die in veränderbarem Leistungsgefälle gegenüber der Randbeheizung 9 betrieben werden kann.The heating resistor 8 is laid in a double spiral approximately in such a way about the central axis of the radiant heater 1 that its two connection ends 14 lie on the periphery of the heating field 10 which is essentially delimited by the outermost, approximately annularly closed spiral winding. A predetermined number of outer turns of the heating resistor 8, namely about half of all turns or about three spiral turns in the exemplary embodiment shown, are provided as the heating-up edge heating 9 for operation with a relatively increased radiation density during the heating-up phase, while the rest lie within this heating edge 9 Windings of the same heating resistor form a remaining partial power 11, which can be operated in a variable power gradient with respect to the edge heating 9.

Der gesamte Strahlheizer 7, also der einzige diesen bildende Heizwiderstand 8 wird während des gesamten Heizbetriebes über eine einstellbare Regeleinrichtung oder ein beispielsweise taktendes Leistungssteuergerät betrieben, unter dessen Zwischenschaltung der Strahlheizer 7 an den Netzstrom angeschlossen ist. Zweckmäßig befindet sich im Raum zwischen dem Strahlheizer 7 und der Heizplatte 2 ein das Heizfeld 10 überkreuzender Temperaturfühler 16, der im Falle der Verwendung einer Regeleinrichtung 12 für den Betrieb des Strahlheizers 7 diese beeinflussen oder einem Temperaturbegrenzer 15 zugeordnet sein kann, dessen Schaltkopf unmittelbar an der Außenseite des vom Temperaturfühler 16 durchsetzten Trägers 4 angeordnet ist.The entire jet heater 7, that is to say the only heating resistor 8 forming this, is operated during the entire heating operation by means of an adjustable control device or, for example, a clocking power control device, with the jet heater 7 being connected to the mains current with the interposition thereof. Appropriately, there is a temperature sensor 16 crossing the heating field 10 in the space between the radiant heater 7 and the heating plate 2, which in the case of using a control device 12 for the operation of the Jet heater 7 can influence this or can be assigned to a temperature limiter 15, the switching head of which is arranged directly on the outside of the carrier 4 penetrated by the temperature sensor 16.

Für den hinsichtlich der relativen Strahlungsdichte unterschiedlichen Betrieb des Strahlheizers 7 in der Ankochphase einerseits und in der Fortkochphase andererseits ist eine zusätzliche Regeleinrichtung 13 vorgesehen, deren Temperaturfühler 17 der Temperatur im Inneren bzw. im Vollquerschnitt der Innenschale 5 ausgesetzt ist. Der Temperaturfühler 17, der ein Dehnstabfühler mit einem Außenrohr und einem darin angeordneten Innenstab unterschiedlicher Ausdehnungskoeffizienten oder ein Wärmeleitstab sein kann, welcher die Wärme von der Fühlstelle dem unterhalb des Schaltkopfes des Temperaturbegrenzers 15 an der Außenseite des Trägers 4 liegenden Schaltkopf der Regeleinrichtung 13 zuführt, liegt ebenfalls parallel zur Heizplatte 2, jedoch unterhalb der den Strahlheizer 7 aufnehmenden Bodenfläche der Innenschale 5 und oberhalb von deren Unterseite, also auf der von der Heizplatte 2 bzw. dem Temperaturfühler 16 abgekehrten Seite des Strahlheizers 7 in den Isolationswerkstoff der Innenschale 5 eingebettet und etwa radial zur Mittelachse des Strahlheizkörpers 1, wobei dieser Temperaturfühler 17 kürzer als die Hälfte der Weite des Heizfeldes 10 derart sein kann, daß er nur auf einer Seite von dessen Mittelachse im wesentlichen ausschließlich im Bereich der zugehörigen Windungen der Randbeheizung 9 liegt. Der im Schaltkopf der als Abschalteinrichtung ausgebildeten Regeleinrichtung 13 angeordnete Ankochschalter 18 in Form beispielsweise eines Schnappschalters, der nicht unmittelbar an die Stromzufuhr für den Strahlheizer 7 angeschlossen ist, ist in einem Kurzschlußkreis einer Kurzschlußschaltung für die Teilleistung 11 angeordnet, also über seine beiden Anschlußpole ausschließlich mit zwei im Abstand zueinanderliegenden Stellen des Heizwiderstandes 8 so elektrisch leitend verbunden, daß bei geschlossenem Ankochschalter der der Teilleistung 11 zugehörige, die Innenzone des Heizfeldes 10 belegende Längsabschnitt des Heizwiderstandes 8 durch Kurzschließen im wesentlichen außer Betrieb genommen ist. Dadurch wird der der Ankoch-Randbeheizung zugehörige restliche und im wesentlichen bis an die Peripherie des Heizfeldes 10 reichende Längsabschnitt des Heizwiderstandes 8 während der geschlossenen Kurzschlußschaltung 19 mit relativ wesentlich erhöhter Strahlungsdichte betrieben und nach dem Einschalten sehr schnell so weit aufgeheizt, daß durch, die Heizplatte 2 ein sichtbares Glühen wahrgenommen werden kann. Sobald der Temperaturfühler 17, der in inniger Berührung mit dem Isolationswerkstoff oder in einem Hohlraum in der Innenschale 5 im wesentlichen berührungsfrei eingebettet sein kann, mit der infolge seiner wärmegedämmten Anordnung gegebenen Zeitverzögerung auf die Abschalttemperatur der Regeleinrichtung 13 erwärmt worden ist, öffnet der Ankochschalter 18, so daß nunmehr auch der der Teilleistung 11 zugehörige Längsabschnitt des Heizwiderstandes 8 in vollen Leistungsbetrieb geht und somit der Unterschied der Strahlungsdichte zwischen dem Bereich der Ankoch-Randbeheizung 9 und demjenigen der Teilleistung 11 zumindest reduziert wird. Dadurch soll während des Ankochens möglichst lange erhöhte Leistung zur Verfügung stehen, ohne daß während des Fortkochens und nach Ansprechen des die Regeleinrichtung 13 bildenden Temperaturwächters wieder eine Rückschaltung auf die erhöhte Leistung erfolgt.An additional control device 13, whose temperature sensor 17 is exposed to the temperature inside or in the full cross section of the inner shell 5, is provided for the different operation of the radiant heater 7 in the parboiling phase on the one hand and in the boiling phase on the other hand with regard to the relative radiation density. The temperature sensor 17, which can be an expansion rod sensor with an outer tube and an inner rod arranged therein with different expansion coefficients, or a heat conducting rod which supplies the heat from the sensing point to the switching head of the control device 13 below the switching head of the temperature limiter 15 on the outside of the carrier 4 also parallel to the heating plate 2, but below the bottom surface of the inner shell 5 receiving the radiant heater 7 and above its underside, i.e. on the side of the radiant heater 7 facing away from the heating plate 2 or the temperature sensor 16, embedded in the insulation material of the inner shell 5 and approximately radially to the central axis of the radiant heater 1, wherein this temperature sensor 17 can be shorter than half the width of the heating field 10 such that it essentially only on one side of its central axis in the area of the associated turns of the edge heating 9 l weighs. Arranged in the switching head of the control device 13 designed as a cut-off switch 18 in the form of, for example, a snap switch, which is not directly connected to the power supply for the radiant heater 7, is arranged in a short-circuit circuit of a short-circuit for the partial power 11, that is to say exclusively via its two connecting poles two points at a distance from each other of the heating resistor 8 so electrically connected that when the parboiler 11 is closed, the longitudinal section of the heating resistor 8 belonging to the partial power 11 and occupying the inner zone of the heating field 10 is essentially taken out of operation by short-circuiting. As a result, the remaining section of the heating resistor 8 associated with the parboiler heating and operating essentially up to the periphery of the heating field 10 is operated during the closed short-circuit circuit 19 with a relatively substantially increased radiation density and, after being switched on, is heated up very quickly so that the heating plate 2 a visible glow can be perceived. As soon as the temperature sensor 17, which can be embedded essentially in contact with the insulation material or in a cavity in the inner shell 5, has been heated to the switch-off temperature of the control device 13 with the time delay due to its thermally insulated arrangement, the heating switch 18 opens, so that now also the longitudinal section of the heating resistor 8 belonging to the partial power 11 goes into full power operation and thus the difference in radiation density between the area of the heating edge heating 9 and that of the partial power 11 is at least reduced. As a result, increased power should be available for as long as possible during the boiling process, without switching back to the increased power again during continued cooking and after the temperature monitor forming the control device 13 has responded.

Die durch die erfindungsgemäße Ausbildung zu erzielende Verkürzung der Ankochzeit ergibt sich auch aus dem Umstand, daß der Kochgefäßboden 3 von Kochgefäßen in der Regel derart gewölbt ist, daß der Kochgefäßboden 3 im Bereich seines Außenrandes den direktesten Kontakt zur Heizplatte 2 hat und daher dort ein besonders schneller Wärmetransport möglich ist. In Fig. 3 ist mit Pfeilen, deren Länge die Strahlungsdichte repräsentieren, angedeutet, daß beim Erfindungsgegenstand eine Betriebsanordnung derart vorgesehen ist, daß in der Ankochphase die Leistungsdichte in diesem Randbereich am größten ist. In der Fortkochphase kann dabei entweder diese äußere Leistungsdichte im Randbereich 9 zurückgefahren, die Leistungsdichte im Bereich der Teilleistung 11 hochgefahren werden oder es können beide Vorgänge gleichzeitig durchgeführt werden. Die Schalthysterese der Regeleinrichtung 13 ist so groß gewählt, daß sie vor dem nahezu vollständigen Abkühlen des Strahlheizkörpers 1 nicht mehr in Kurzschlußstellung, also in Schließstellung des Ankochschalters 18 zurückschaltet.The shortening of the boil-up time to be achieved by the design according to the invention also results from the fact that the cooking vessel base 3 of cooking vessels is usually curved in such a way that the cooking vessel base 3 has the most direct contact with the heating plate 2 in the region of its outer edge and therefore there is a particular one faster heat transfer is possible. In FIG. 3, arrows, the length of which represent the radiation density, indicate that an operating arrangement is provided in the subject matter of the invention in such a way that the power density is greatest in this edge region in the boiling phase. In the continued cooking phase, either this external power density in the edge area 9 can be reduced, the power density in the area of the partial power 11 can be increased, or both processes can be carried out simultaneously. The switching hysteresis of the control device 13 is chosen so large that it no longer switches back to the short-circuit position, that is to say in the closed position of the parboiler switch 18, before the radiant heater 1 has almost completely cooled.

Anstatt den der inneren Teilleistung 11 zugehörigen Längsabschnitt des Heizwiderstandes 8 für die Ankochphase kurzzuschließen, kann dieser Längsabschnitt auch durch einen Heizleiter mit hohem positivem Temperaturkoeffizienten gebildet sein, der beispielsweise aus Molybdän-Disilizid besteht. Dieser, zwar durch einen gesonderten, in Reihe mit dem übrigen Heizwiderstand bzw. mit dem der Ankoch-Randbeheizung 9 zugehörigen Längsabschnitt geschaltete PTC-Widerstand bewirkt sofort nach dem Einschalten des Strahlheizkörpers aufgrund seines geringeren Anfangswiderstandes einen sehr hohen Anlaufstrom und zusätzlich signalisiert dieser PTC-Widerstand durch schnelle Erwärmung auf Glühtemperatur auch optisch ein ähnlich schnelles Aufheizen des Strahlheizkörpers, wie das bei der Verwendung von Halogenlampen als Strahlheizer der Fall ist. Danach regelt sein sich erhöhender Eigenwiderstand die Leistung in der Fortkochphase selbsttätig zurück.Instead of short-circuiting the longitudinal section of the heating resistor 8 associated with the inner partial power 11 for the boil-up phase, this longitudinal section can also be formed by a heating conductor with a high positive temperature coefficient, which consists, for example, of molybdenum disilicide. This, by a separate PTC resistor connected in series with the rest of the heating resistor or with the longitudinal section associated with the parboiler heating 9, causes a very high starting current immediately after switching on the radiant heater due to its lower initial resistance and additionally signals this PTC resistor due to rapid heating to the annealing temperature, the radiant heater is visually similarly quick to heat up, as is the case when using halogen lamps as radiant heaters. After that its increasing inherent resistance automatically regulates the power in the continued cooking phase.

Der Träger 4 ist mit der Stirnseite des Schalenrandes der Innenschale 5 unter Druck ganzflächig gegen die Innen- bzw. Unterseite der Heizplatte gespannt, so daß also der Innenumfang dieses Anlagerandes im wesentlichen mit der Peripherie bzw. Außenbegrenzung des Heizfeldes 10 zusammenfällt. Der Heizwiderstand 8 kann durch wenigstens teilweise Einbettung seiner Wendeln in den Isolierwerkstoff der Innenschale 5 unverrückbar gegenüber dieser festgelegt sein. Ferner kann der Strahlheizkörper im Grundriß statt kreisrund auch von der Kreisform abweichend rund oder rechtekkig bzw. quadratisch ausgebildet sein, wobei dann der Heizwiderstand zweckmäßig in seiner Spiralform dieser Außenkontur folgt.The carrier 4 is stretched with the end face of the edge of the shell of the inner shell 5 under pressure over the entire surface against the inside or underside of the heating plate, so that the inner circumference of this contact edge essentially coincides with the periphery or outer boundary of the heating field 10. The heating resistor 8 can be immovably fixed to the inner shell 5 by at least partially embedding its coils in the insulating material. Furthermore, the radiant heater can also be round, rectangular or square, deviating from the circular shape, instead of being circular, the heating resistor then expediently following this outer contour in its spiral shape.

In den Fig. 4 bis 7 sind für einander entsprechende Teile die gleichen Bezugszeichen wie in den Fig. 1 bis 3, jedoch in den Fig. 4 und 5 mit dem Index "a" und in den Fig. 6 und 7 mit dem Index "b" verwendet.4 to 7 are the same reference numerals for corresponding parts as in Figs. 1 to 3, but in Figs. 4 and 5 with the index "a" and in Figs. 6 and 7 with the index " b "is used.

Der Strahlheizkörper 1a gemäß den Fig. 4 und 5 weist als Ankoch-Randbeheizung 9a einen in nur einem einzigen Umgang, also nur in einer einstrangigen Schlinge oder bifilar verlegten äußersten Heizwiderstand aus besonders dünnem, hochbelastbaren Widerstandsdraht auf, also aus einem Widerstandsdraht, der dünner und höherbelastbar bzw. belastet ist, als der der Teilleistung 11 zugehörige Heizwiderstand. Der Strahlheizer dieses Strahlheizkörpers 1 ist also im Grunde genommen zweikreisig ausgebildet, jedoch sind die beiden Heizkreise parallel oder in Reihe so geschaltet, weshalb sie stets simultan ein- und ausgeschaltet sind.The radiant heater 1 a according to FIGS. 4 and 5 has as the parboiling edge heater 9 a one in only one operation, that is, only in a single-strand loop or bifilar external heating resistor made of particularly thin, heavy-duty resistance wire, i.e. of a resistance wire that is thinner and is more resilient or loaded than the heating resistor belonging to the partial power 11. The radiant heater of this radiant heater 1 is basically of two-circuit design, but the two heating circuits are connected in parallel or in series, which is why they are always switched on and off simultaneously.

Wie Fig. 5 zeigt, besteht die Innenschale 5a aus zwei aufeinanderliegenden Tragkörpern 20, 21 unterschiedlicher Isolierwerkstoffe und Dicken, wobei der untere, plattenförmig geschüttete Tragkörper 20 aus einer pulvrigen gepressten Masse besteht, relativ druckelastisch ist, eine größere Dicke als der ganzflächig daraufliegende Formkörper 21 hat und vor allem einen thermischen Isolationswert aufweist, der wesentlich höher als derjenige des Tragkörpers 21 ist. Demgegenüber ist der beispielsweise scheibenförmige Tragkörper 21 ein relativ formstabiler Formkörper aus verpressten mineralischen Fasern, an welchem die Heizwiderstände durch stellenweise Einbettung gehaltert sind. Dieser Tragkörper 21 weist an der Oberseite nach oben etwa um seine übrige Dicke vorstehende, zur Mittelachse des Strahlheizkörpers 1a etwa radiale und einteilig mit dem übrigen Tragkörper 21 ausgebildete Stege auf. Die nur im radial äußeren Bereich des Heizfeldes liegenden Stege sind jeweils zwischen Vertiefungen 23 gebildet, welche von der Peripherie des Heizfeldes nur über einen Teil der Windungen der Heizwiderstände reichen. Die radial innerhalb der Vertiefungen 23, also im Mittelbereich liegenden Windungen stehen daher in direkter Berührung mit der Innenschale 5a. Im Bereich der Stege 22, die außer der Ankoch-Randbeheizung 9a noch drei weitere Windungen des Heizwiderstandes 8a erfassen, sind diese Windungen durch Einbettung ausschließlich an den Stegen 22 gehaltert, während sie gemäß Fig. 5 im Bereich der Vertiefungen diese frei schwebend, also gegenüber der Innenschale 5a berührungsfrei überspannen bzw. überbrücken oder nur schwach aufliegen. Der Abstand der die Vertiefungen parallel zu deren Bodenflächen überbrückenden Längsabschnitte der Heizwiderstände von diesen Bodenflächen kann kleiner als der Außendurchmesser dieser Heizwiderstände, insbesondere etwa halb so groß sein, während die Heizwiderstände in die Stege 22 etwa um die Hälfte ihres Außendurchmessers eingebettet sind. Der Abstand zwischen benachbarten Stegen kann etwa dem doppelten von deren Breite entsprechen.5 shows, the inner shell 5a consists of two superimposed supporting bodies 20, 21 of different insulating materials and thicknesses, the lower, panel-shaped supporting body 20 consisting of a powdery pressed mass, being relatively pressure-elastic, a greater thickness than the molded body 21 lying thereon over the entire surface has and above all has a thermal insulation value which is significantly higher than that of the support body 21. In contrast, the disk-shaped support body 21, for example, is a relatively dimensionally stable molded body made of pressed mineral fibers, on which the heating resistors are held by embedding in places. This support body 21 has on the upper side upwards about its remaining thickness, approximately radial to the central axis of the radiant heater 1 a and integrally formed with the rest of the support body 21 webs. The webs lying only in the radially outer region of the heating field are each formed between depressions 23, which extend from the periphery of the heating field only over part of the turns of the heating resistors. The windings lying radially inside the depressions 23, that is to say in the central region, are therefore in direct contact with the inner shell 5a. In the area of the webs 22, which in addition to the parboiler edge heating 9a also detect three further turns of the heating resistor 8a, these turns are held by embedding exclusively on the webs 22, while according to FIG. 5 they float freely in the area of the depressions, that is to say opposite span or bridge the inner shell 5a without contact or only lie weakly. The distance of the longitudinal sections of the heating resistors bridging the depressions parallel to their bottom surfaces from these bottom surfaces can be smaller than the outside diameter of these heating resistors, in particular about half as large, while the heating resistors are embedded in the webs 22 by about half their outside diameter. The distance between adjacent webs can be approximately twice their width.

Wie die Fig. 6 und 7 zeigen, können im oberen Tragkörper 21 statt der Vertiefungen 23 auch Durchbrüche bzw. über die Dicke des Tragkörpers 21b durchgehende Öffnungen 23b vorgesehen sein, welche wenigstens teilweise von Vorsprüngen 24 des unteren Tragkörpers 20b steckgliedartig ausgefüllt sind. Die Vorsprünge 24 reichen im dargestellten Ausführungsbeispiel nach oben über die Oberseiten der Stege 22b geringfügig hinaus, sind jedoch im Bereich jedes sie überquerenden Längsabschnittes des jeweiligen Heizwiderstandes mit rinnenförmigen Aufnahmenuten 25 versehen, deren Bodenflächen geringfügig tiefer als die Oberseite der Stege 21b liegen können. Die Tiefe der Aufnahmenuten 25, gegenüber denen die zugehörigen Längsabschnitte der Heizwiderstände berührungsfrei oder lediglich uneingebettet lose anliegend vorgesehen sein können, ist zweckmäßig so groß, daß die benachbarte Aufnahmenuten 25 voneinander trennenden Stege des Tragkörpers 21b nur etwa bis zur Mitte des Außendurchmessers dieser Längsabschnitte reichen. Durch die beschriebene Ausbildung ist die Wärmeableitung von den genannten, zwischen den Stegen 21 liegenden Längsabschnitten der Strahlheizkörper in die Innenschale 5b besonders gering, so daß diese Längsabschnitte nach dem Einschalten vom kalten Zustand sehr schnell zum sichtbaren Glühen kommen. Dadurch, daß der Tragkörper 20b durch die Vorsprünge 24 wenigstens in einigen, rasterartig verteilten Zonen über die Unterseite des Tragkörpers 21 b hinaus verdickt ist, ergibt sich eine hervorragende zusätzliche Wärmedämmung. Er könnte aber auch eben sein.As shown in FIGS. 6 and 7, in the upper support body 21, instead of the depressions 23, openings or openings 23b which are continuous over the thickness of the support body 21b can also be provided, which are at least partially filled by projections 24 of the lower support body 20b. In the exemplary embodiment shown, the projections 24 extend slightly above the upper sides of the webs 22b, but are provided with channel-shaped receiving grooves 25 in the region of each longitudinal section crossing them, the bottom surfaces of which can be slightly lower than the upper side of the webs 21b. The depth of the receiving grooves 25, relative to which the associated longitudinal sections of the heating resistors can be provided in a contact-free manner or only loosely but without embedded, is expediently so great that the adjacent receiving grooves 25 separating webs of the support body 21b only extend approximately to the middle of the outer diameter of these longitudinal sections. As a result of the design described, the heat dissipation from the above-mentioned longitudinal sections of the radiant heaters lying between the webs 21 into the inner shell 5b is particularly low, so that these longitudinal sections very quickly come to a visible glow after being switched on from the cold state. The fact that the support body 20b is thickened by the projections 24 at least in some, grid-like zones beyond the underside of the support body 21b, results in excellent additional thermal insulation. But it could also be.

Im Falle der Ausbildung nach Fig. 1 kann die Regeleinrichtung 13 ähnlich wie diejenige nach der DE-OS 32 47 028 bzw. diejenige nach der EP-A-01 14 307 ausgebildet sein, auf die wegen weiterer Einzelheiten Bezug genommen wird. Die Ankoch-Randbeheizung liegt im selben, vom Träger 4 und der Heizplatte 2 umschlossenen Raum wie der übrige Strahlheizer 7 und ist von diesem nicht durch einen Zwischensteg des Trägers ringförmig getrennt.1, the control device 13 can be similar to that according to DE-OS 32 47 028 or that according to EP-A- 01 14 307, to which reference is made for further details. The parboiler heating is in the same space as that of the rest of the jet heater 7, which is enclosed by the carrier 4 and the heating plate 2, and is not separated from it in a ring shape by an intermediate web of the carrier.

Es ergibt sich bei der Erfindung im Außenbereich eine höhere spezifische Leistung, die unter Umständen so hoch sein kann, wie man sie im Dauerbetrieb dem Heizwiderstand und/oder der Glaskeramikplatte nicht zumuten könnte. Durch ihre meist nur temporäre Wirkung und die höhere Leistungsabnahme in diesem Bereich, insbesondere während der Ankochphase, löst sie aber keine schädlichen Wirkungen aus. Es könnte auch generell im Außenbereich eine höhere spezifische Leistung vorgesehen sein. Sie wirkt sich hauptsächlich während der Ankochzeit aus, indem der äußere Heizleiter schneller glüht, damit die erwünschten optischen Wirkungen auslöst und früher mit der Wärmeübertragung an das Kochgefäß beginnt. Während der Fortkochphase spielt diese vorteilhaft ohne Umschaltung aufrechterhaltene Leistungsverteilung mit Bevorzugung des Randbereiches sich kaum, zumindest aber nicht negativ aus, weil dann die Gesamtleistung z.B. durch taktendes Ein- und Ausschalten der Gesamtleistung herabgesetzt ist. Es hat sich gezeigt, daß eine höhere spezifische Belastung des Randbereiches und insbesondere der äußeren Heizleiterwindung für deren Lebensdauer keine wesentliche Rolle spielt, da diese selbst bei einiger Überlastung nicht durchbrennen.The invention results in a higher specific power in the outdoor area, which may be as high as it could not be expected from the heating resistor and / or the glass ceramic plate in continuous operation. Due to its mostly temporary effect and the higher power consumption in this area, especially during the parboiling phase, it does not trigger any harmful effects. In general, a higher specific power could also be provided outdoors. It mainly has an effect during the heating-up time, in that the outer heating conductor glows faster, so that the desired optical effects are triggered and heat transfer to the cooking vessel begins earlier. During the continued cooking phase, this power distribution, which is advantageously maintained without switching, hardly plays out, at least not negatively, because the total power then e.g. is reduced by cyclical switching on and off of the total power. It has been shown that a higher specific load on the edge area and in particular on the outer heating conductor winding does not play an important role in their service life, since these do not burn out even with some overload.

Claims (13)

1. Radiant heater unit (1) for heating a hotplate (2), particularly a glass ceramic hotplate, with at least one cooking point and a support (4) for an electric radiant heater (7) having at least one radiant heating resistor (8), such as a heater coil, the radiant heater (7) extending from a circular periphery of a heating field (10) determining a fixed heating field magnitude over a central zone into an inner zone of the heating field and an area of the radiant heater (7) associated with a partial power system forms at the periphery of the heating field (10) a marginal heating system (9) around an inner area associated with a further partial power system and control means for the initial cooking operation of the marginal heating system (9) are provided with a predetermined radiation density, characterized in that the control means for the initial cooking operation of the marginal heating system (9) are constructed with a higher radiation density than that of the inner area.
2. Radiant heater unit according to claim 1, characterized in that the marginal heating system (9) is connected with a higher power over the entire initial cooking phase as compared with the inner area and that preferably the control means are constructed for switching to final cooking operation, in which a heater of the marginal heating system (9) is operated with a power lower than in the initial cooking phase.
3. Radiant heater unit according to claims 1 or 2, characterized in that a partial power system (11) of the radiant heater (7) is switched for ending the initial cooking phase in a substantially time-dependent manner, preferably by means of a temperature switch with a high switching temperature difference or hysteresis and/or with a low thermal coupling to the radiant heater
4. Radiant heater unit according to one of the preceding claims, characterized in that the control of the initial cooking phase is formed by a short-circuit circuit (19) of the inner part of the radiant heater (7), the marginal heating system (9) and the inner part of the radiant heater (7) being in particular formed by a single radiant heating resistor.
5. Radiant heater unit according to one of the preceding claims, characterized in that the inner area of the radiant heater (7) is formed by a radiant heating resistor with a high positive temperature coefficient (PTC).
6. Radiant heater unit according to one of the preceding claims, characterized in that the marginal heating system (9a) is formed by a separate heating circuit, which in particular extends in single-strand or bifilar manner over approximately 360°.
7. Radiant heater unit according to one of the preceding claims, characterized in that at least the marginal heating system (9a) with a lower thermal conduction coupling than the inner part of the radiant heater (7a) is connected to the support (4a) and preferably has a smaller specific surface contact with the support (4a) than the inner area.
8. Radiant heater unit according to one of the preceding claims, characterized in that the control means are in particular exclusively formed by the heat conducting connection between the radiant heater (7a) and the support (4a).
9. Radiant heater unit according to one of the preceding claims, characterized in that the longitudinal portions of at least the heating resistor of the marginal heating system (9a) are arranged in substantially freely suspended, contact-free manner with respect to the support (4a).
10. Radiant heater unit according to one of the preceding claims, characterized in that the longitudinal portions of at least the heating resistor of the marginal heating system (9b) are in particular arranged in alternating manner in regions of the support (4b) having different thermal conductivity characteristics.
11. Radiant heater unit according to one of the preceding claims, characterized in that a side of said support (4b) receiving said radiant heater is provided by two superimposed support bodies (20b, 21 b), the lower one of which having a minor specific thermal conductivity and penetrating openings (23b) in the upper support body (21b) at least in the vicinity of the marginal heating system (9b).
12. Radiant heater unit according to claim 11, characterized in that the support (4a) has a thick-walled inner shell (5a) made from insulating material for receiving the radiant heater (7a) and a thin-walled outer shell (6a) as a reinforcement and that preferably the upper support body (21) is made from fibrous insulating material and/or the lower support body (20) is made from substantially pulverulent insulating material.
13. Radiant heater unit according to one of the preceding claims, characterized in that an initial cooking regulating device (13) has a temperature sensor (17), particularly constructed as an expansion rod sensor and which is preferably thermally insulated by means of an insulating layer with respect to the radiant heater (7) and is in particular embedded in the inner shell (5).
EP87107772A 1986-07-03 1987-05-28 Radiant heating element Expired - Lifetime EP0250880B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87107772T ATE69495T1 (en) 1986-07-03 1987-05-28 RADIANT HEATER.

Applications Claiming Priority (2)

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DE19863622415 DE3622415A1 (en) 1986-07-03 1986-07-03 BEAM RADIATOR
DE3622415 1986-07-03

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EP0250880A2 EP0250880A2 (en) 1988-01-07
EP0250880A3 EP0250880A3 (en) 1989-02-08
EP0250880B1 true EP0250880B1 (en) 1991-11-13
EP0250880B2 EP0250880B2 (en) 1997-04-23

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US (1) US4810857A (en)
EP (1) EP0250880B2 (en)
JP (1) JPS6366891A (en)
AT (1) ATE69495T1 (en)
AU (1) AU596673B2 (en)
DE (2) DE3622415A1 (en)
ES (1) ES2027255T3 (en)
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DE807698C (en) * 1949-07-24 1951-07-02 Otto Kiefer Dipl Kfm Thermostat consisting of two metal rods with different expansion coefficients
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US3912905A (en) * 1974-02-25 1975-10-14 Kanthal Corp Electric resistance heating device
US4008454A (en) * 1975-11-04 1977-02-15 General Electric Company Differential expansion rod and tube thermostat
DE2729929C3 (en) * 1977-07-02 1981-10-08 Karl 7519 Oberderdingen Fischer Radiant heating unit for glass ceramic electric cookers
DE2820114A1 (en) * 1978-05-09 1979-11-15 Karl Fischer Radiation heating unit for cooking utensils - has insulating support for resistors with transverse elevations in which resistors are partly embedded
DE3007037A1 (en) * 1980-02-26 1981-09-03 Ego Elektro Blanc & Fischer GLASS CERAMIC COOKER
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US4574187A (en) * 1980-08-29 1986-03-04 Sprague Electric Company Self regulating PTCR heater
DE8133341U1 (en) * 1980-11-17 1982-03-25 Micropore International Ltd., Droitwich, Worcestershire ELECTRIC RADIATION HEATER FOR COOKERS WITH GLASS CERAMIC COVER PANELS
GB2087698B (en) * 1980-11-17 1984-03-28 Micropore International Ltd Electric radiant heater unit
DE3206024A1 (en) * 1982-02-19 1983-09-08 Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart ELECTRIC COOKING PLATE, PREFERABLY GLASS-CERAMIC COOKER
EP0103741B1 (en) * 1982-09-16 1988-11-17 E.G.O. Elektro-Geräte Blanc u. Fischer Heating element, especially radiant heating element for the heating of ceramic plates
DE3314501A1 (en) * 1983-04-21 1984-10-25 Ego Elektro Blanc & Fischer Heating element, especially a radiant heating element for heating glass-ceramic plates
DE3247028A1 (en) 1982-12-18 1984-06-20 Ego Elektro Blanc & Fischer TEMPERATURE CONTROL DEVICE FOR A HEATER
IT8320567V0 (en) * 1983-01-21 1983-01-21 I R C A Ind Resistenze Corazza ELECTRIC HEATING ELEMENT, IN PARTICULAR FOR SMOOTH COOKING HOBS.
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Also Published As

Publication number Publication date
ES2027255T3 (en) 1992-06-01
EP0250880A2 (en) 1988-01-07
EP0250880A3 (en) 1989-02-08
DE3622415A1 (en) 1988-01-07
ATE69495T1 (en) 1991-11-15
US4810857A (en) 1989-03-07
YU107487A (en) 1989-12-31
JPS6366891A (en) 1988-03-25
AU596673B2 (en) 1990-05-10
AU7520687A (en) 1988-01-07
EP0250880B2 (en) 1997-04-23
DE3774497D1 (en) 1991-12-19

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