EP0035254B1 - Electric heating equipment for ranges or cooking tops - Google Patents

Electric heating equipment for ranges or cooking tops Download PDF

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Publication number
EP0035254B1
EP0035254B1 EP81101442A EP81101442A EP0035254B1 EP 0035254 B1 EP0035254 B1 EP 0035254B1 EP 81101442 A EP81101442 A EP 81101442A EP 81101442 A EP81101442 A EP 81101442A EP 0035254 B1 EP0035254 B1 EP 0035254B1
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EP
European Patent Office
Prior art keywords
heat
heating coil
mounting
plate
foil
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EP81101442A
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German (de)
French (fr)
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EP0035254A1 (en
Inventor
Ingo Dipl.-Ing. Dr. Bleckmann
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ELPAG AG CHUR
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ELPAG AG CHUR
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Priority to AT81101442T priority Critical patent/ATE7254T1/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

Definitions

  • the invention relates to an electric heating device for cookers or hot plates, in which a heat-resistant holder is arranged under a plate that is permeable to heat rays, in particular under a ceramic glass plate, which receives an electric heating coil and in which the holder is in a cavity between the glass plate and a heat-insulating one Layer or a warming body is arranged, wherein the heat-insulating layer is covered by a reflective film.
  • Electric cookers that are equipped with so-called “jet hot plates” are becoming increasingly popular.
  • the stove surface is formed, for example, by a glass plate.
  • Circular, square or rectangular electrical heating devices are located under the glass plate.
  • the heat generated by the electrical heating device is predominantly transmitted by radiation to cooking or roasting dishes, which are placed on the glass plate.
  • the heating coil must be brought to a correspondingly high temperature so that the required heat output is transferred to the cooking or roasting vessel when it is parked.
  • this high temperature considerably reduces the life of the heating coil.
  • the invention has for its object to propose a heating device of the type in question, in which the heat flow from the heating coil down, d. H. in the direction facing away from the glass plate, is considerably reduced and a uniform heat emission to the cooking vessel is achieved.
  • the temperature of the heating coil can be about 50 ° -100 ° C, otherwise the dimensions are the same. H. from Z. B. 1000 ° C to 950 ° C or 900 ° C, which results in about a doubling of the life of the heating coil.
  • a bracket 1 for a Walkeri 2 consists of a z. B. made of magnesite, refractory stone, which is H-shaped in cross section, d. That is, a round or square or rectangular plate 3 has webs 4 in one piece. Grooves 5 are embossed in the surface of the plate. Depending on the desired power levels of the plates, one or more heating coils 2 can be inserted into the grooves, which are operated in series or parallel connection or in individual connection.
  • the bottom of the groove 5 is at a distance of through holes or slot-shaped recesses 6 arranged one above the other, through which a convection air stream is sucked in during operation from the heated heating coil 2, as is indicated by the arrows in FIG. 1.
  • This convection air flow cools the heating coil, so that its temperature is about 30-50 ° C. lower in comparison to an embodiment of the same power, but without the holes or recesses 6.
  • Further holes or recesses 7 are provided between the windings of the heating coil 2 through which the convection air flow can drop when it has given off heat to the ceramic glass plate 8.
  • a bracket or a shell 9 which carries a heat insulation layer 10 or a heat insulation body.
  • a radiation-reflecting film 11, in particular an aluminum film, is placed on the heat-insulating body 10.
  • the legs 4 of the holder 1 are supported on the one hand on the underside of the glass plate 8 and on the other hand on the film 11 or on the thermal insulation layer 10.
  • a cavity is created, which is divided by the plate 3 into approximately two halves 12a and 12b of equal size.
  • the temperature can be sensed, for example, in the cavity 12a by means of a thermostat device 13 which extends diagonally through the arrangement.
  • the heating coil 2 is at a distance from the plate 8, a correspondingly wide section of the radiation cone 14 hits the plate 8, so that a uniform heat emission on the cooking vessel or a corresponding pan, not shown, is achieved and local unwanted overheating is excluded. Furthermore, this keeps the load on the plate 8 within limits.
  • the heat radiated downward from the underside of the plate 3 is largely radiated back through the film 11.
  • the cavity 12b now has two very important functions:
  • the cavity 12b can be dimensioned such that the heat-reflecting film 11 does not assume a temperature which would be above its softening temperature or even melting temperature.
  • a corresponding air convection is created through the cutouts 6, 7, which ensures a corresponding compensation.
  • the convection flow can be very different, depending on the temperature at the top of the plate. In general, the temperature on the plate 8 by the cooked or roasted material will be lower than the temperature on the surface of the film 11. The cooled air accordingly falls through the recesses 7 and cools the space 1 2b, then through other recesses 6 rises again. The effect is particularly pronounced when 13 strings of the heating coil 2 have been switched off by the temperature control.
  • the task mentioned at the outset namely lowering the temperature of the heating coil by 50-100 ° C. while the heating output is otherwise the same, is significantly supported if the holder 1 is made from a material which has very good thermal conductivity with very poor electrical conductivity. Values such as those achieved by magnesium oxide pressed bodies are preferred.
  • the holder should accordingly consist of MgO or a ceramic that has values similar to those of an MgO compact.

Abstract

An electrical heating device for cookers and hot plates is disclosed, having a heat-resistant support member disposed below a heat-radiation transmitting plate, in particular, a glass-ceramic plate. The support member is adapted to receive at least one electric heater filament, wherein the support member is disposed within a hollow space between the heat-radiation transmitting plate and a heat-insulating layer or body. The support member is provided with holes or cut-out portions enforcing convection of the air enclosed within the hollow space, and furthermore, the heat-insulating layer being covered by a reflecting sheet or foil, so that a substantial portion of the heat radiated downwards by the heater filament is directed partially by reflection at the sheet or foil and partially by the air current passing over the sheet or foil onto the heat-radiation transmitting plate and onto a cooking or frying vessel standing thereupon.

Description

Die Erfindung betrifft eine elektrische Heizeinrichtung für Herde oder Kochplatten, bei der unter einer für Wärmestrahlen durchlässigen Platte, insbesondere unter einer Keramikglasplatte, eine hitzebeständige Halterung angeordnet ist, welche eine elektrische Heizwendel aufnimmt und bei der die Halterung in einem Hohlraum zwischen der Glasplatte und einer wärmedämmenden Schicht oder einem wärmenden Körper angeordnet ist, wobei die wärmedämmende Schicht von einer reflektierenden Folie abgedeckt ist.The invention relates to an electric heating device for cookers or hot plates, in which a heat-resistant holder is arranged under a plate that is permeable to heat rays, in particular under a ceramic glass plate, which receives an electric heating coil and in which the holder is in a cavity between the glass plate and a heat-insulating one Layer or a warming body is arranged, wherein the heat-insulating layer is covered by a reflective film.

Elektrische Herde, die mit sogenannten »Strahlkochplatten« ausgerüstet sind, finden zunehmende Verbreitung. Die Herdoberfläche wird beispielsweise von einer Glasplatte gebildet. Unter der Glasplatte befinden sich kreisförmige, quadratische oder rechteckige elektrische Heizeinrichtungen meistens unterschiedlicher Größe. Die von der elektrischen Heizeinrichtung erzeugte Wärme wird überwiegend durch Strahlung auf Koch- oder Bratgefäße übertragen, welche auf der Glasplatte abgestellt werden.Electric cookers that are equipped with so-called “jet hot plates” are becoming increasingly popular. The stove surface is formed, for example, by a glass plate. Circular, square or rectangular electrical heating devices, mostly of different sizes, are located under the glass plate. The heat generated by the electrical heating device is predominantly transmitted by radiation to cooking or roasting dishes, which are placed on the glass plate.

Es ist aus der DE-A1-2 500 586 eine Ausführungsform nach dem Oberbegriff des Patentanspruchs 1 bekannt, bei denen die die Hitze erzeugende Heizwendel in einem bestimmten Abstand von der Unterseite der Glasplatte angeordnet ist. Es wird dabei an der Unterseite der Glasplatte ein schalenförmiges Gebilde aus einem hitzebeständigen Material befestigt. Die Heizwendel ist in den Boden des schalenförmigen Gebildes eingelegt. Diese Ausführungsformen haben den Vorteil, daß die Glasplatte nicht unmittelbar mit der relativ hohen Temperatur der Heizwendel belastet wird und daß jede Heizwendel durch die Verbreiterung des Strahlungskegels einen größeren Abschnitt der Glasplatte bestrahlt. Auf diese Weise wird also die durch die Glasplatte hindurchgehende Strahlung gleichmäßiger verteilt. Der Nachteil dieser Ausführungsformen liegt darin, daß ein relativ sehr hoher Anteil der von der Heizwendel erzeugten Wärmeenergie nach unten abgeleitet wird und dementsprechend verlorengeht. Diese Verluste wirken sich einerseits in der Energiebilanz ungünstig aus, andererseits muß die Heizwendel auf eine entsprechend hohe Temperatur gebracht werden, damit die geforderte Wärmeleistung auf das abgestellte Koch- oder Bratgefäß übertragen wird. Durch diese hohe Temperatur wird jedoch die Lebensdauer der Heizwendel erheblich verringert.It is known from DE-A1-2 500 586 an embodiment according to the preamble of claim 1, in which the heat-generating heating coil is arranged at a certain distance from the underside of the glass plate. A bowl-shaped structure made of a heat-resistant material is attached to the underside of the glass plate. The heating coil is inserted in the bottom of the bowl-shaped structure. These embodiments have the advantage that the glass plate is not directly loaded with the relatively high temperature of the heating coil and that each heating coil irradiates a larger section of the glass plate due to the widening of the radiation cone. In this way, the radiation passing through the glass plate is distributed more evenly. The disadvantage of these embodiments is that a relatively very high proportion of the thermal energy generated by the heating coil is dissipated downwards and is accordingly lost. On the one hand, these losses have an unfavorable effect on the energy balance, on the other hand, the heating coil must be brought to a correspondingly high temperature so that the required heat output is transferred to the cooking or roasting vessel when it is parked. However, this high temperature considerably reduces the life of the heating coil.

Bei elektrischen Koch- und Brateinrichtungen mit von Luft umstrichenen, freiliegenden Heizwendeln war es z. B. aus den DE-C-554 103, GB-A-212 449, FR-A-459 773, GB-A-246 604, DE-C-385 493 und DE-C-361 768 bereits bekannt, Maßnahmen zu treffen, um die Luftzirkulation zu fördern. Dadurch sollte z. B. die von der Heizwendel erhitzte Luft auf den Boden eines abgestellten Kochgefäßes geleitet werden, um so die Energieausnutzung zu verbessern. Soweit in der Halterung der Heizwendel Löcher angebracht wurden, dienten diese auch dem Abfluß überkochender Flüssigkeit und der Vermeidung von elektrischen Kurzschlüssen durch dieselbe. Nach DE-C-554 103 dienten die im Boden der Rillen angebrachten Löcher dem Ansaugen der Zirkulationsluft. Für den Rückfluß der sich unter dem Kochtopf ansammelnden Luft dienen zwei am seitlichen Ende der Kochplatte angeordnete eigene Kanäle. Eine reflektierende Folie ist dort nicht vorgesehen. Für die Temperaturverteilung ergibt sich daher ein Gefälle von außen nach innen.In electric cooking and roasting equipment with air-wrapped, exposed heating coils, it was e.g. B. from DE-C-554 103, GB-A-212 449, FR-A-459 773, GB-A-246 604, DE-C-385 493 and DE-C-361 768 already known measures to meet to promote air circulation. This should, for. B. the air heated by the heating coil can be directed to the bottom of a parked cooking vessel, so as to improve energy efficiency. Insofar as holes were made in the holder of the heating coil, these also served to drain off boiling liquid and to avoid electrical short-circuits through the same. According to DE-C-554 103, the holes made in the bottom of the grooves were used to draw in the circulation air. Two separate channels arranged at the side end of the hotplate serve for the backflow of the air collecting under the saucepan. A reflective film is not provided there. There is therefore a gradient from outside to inside for the temperature distribution.

Der Erfindung liegt die Aufgabe zugrunde, eine Heizeinrichtung der in Rede stehenden Art vorzuschlagen, bei der der Wärmefluß von der Heizwendel nach unten, d. h. in der von der Glasplatte abgewendeten Richtung, erheblich verringert und eine gleichmäßige Wärmeabgabe an das Kochgefäß erreicht wird.The invention has for its object to propose a heating device of the type in question, in which the heat flow from the heating coil down, d. H. in the direction facing away from the glass plate, is considerably reduced and a uniform heat emission to the cooking vessel is achieved.

Die Lösung der genannten Aufgabe ergibt sich aus den Merkmalen des Anspruchs 1.The solution to the stated problem results from the features of claim 1.

Abgesehen von der besseren Wärmeübertragung auf das Koch- oder Bratgut kann die Temperatur der Heizwendel bei sonst gleicher Dimensionierung um etwa 50°-100°C, d. h. von z. B. 1000°C auf 950°C oder auch 900°C abgesenkt werden, wodurch sich etwa eine Verdoppelung der Lebensdauer der Heizwendel ergibt.Apart from the better heat transfer to the cooking or roasting material, the temperature of the heating coil can be about 50 ° -100 ° C, otherwise the dimensions are the same. H. from Z. B. 1000 ° C to 950 ° C or 900 ° C, which results in about a doubling of the life of the heating coil.

Die abhängigen Unteransprüche beschreiben bevorzugte Ausführungsformen. Zur Erläuterung des Anspruchs 3 sei bemerkt, daß bisher als Träger für die Heizwendel Materialien, auch Fasermaterialien, verwendet wurden, die eine relativ schlechte Wärmeleitfähigkeit λ in der Größenordnung von 0,09 W/m°k bei 1000°C hatten. Es überraschend, daß bei Verwendung von Fasermaterial mit einer um den Faktor 10 besseren Wärmeleitfähigkeit, also z. B. von 0,7 W/m°k bei 1000°C die beabsichtigte Verdoppelung der Lebensdauer der Heizwendel erreicht werden kann.The dependent sub-claims describe preferred embodiments. To explain claim 3 it should be noted that hitherto materials, including fiber materials, have been used as supports for the heating coil, which had a relatively poor thermal conductivity λ of the order of 0.09 W / m ° k at 1000 ° C. It is surprising that when using fiber material with a 10 times better thermal conductivity, ie z. B. of 0.7 W / m ° k at 1000 ° C the intended doubling of the life of the heating coil can be achieved.

Auf der beiliegenden Zeichnung ist eine bevorzugte Ausführungsform der neuen elektrischen Heizeinrichtung dargestellt. Auf den Zeichnungen zeigen:

  • Fig. 1 einen Vertikalteilschnitt der Heizeinrichtung und
  • Fig. 2 eine Schnittansicht längs der Linie II-II in Fig. 1.
A preferred embodiment of the new electric heating device is shown on the accompanying drawing. The drawings show:
  • Fig. 1 is a partial vertical section of the heater and
  • FIG. 2 is a sectional view along the line II-II in FIG. 1.

Eine Halterung 1 für eine Heizwendei 2 besteht aus einem z. B. aus Magnesit gepreßten, feuerfesten Stein, welcher im Querschnitt H-förmig ist, d. h., eine runde oder quadratische oder auch rechteckige Platte 3 besitzt einstückig Stege 4. In die Oberfläche der Platte sind Rillen 5 eingeprägt. Je nach den erwünschten Leistungsstufen der Platten können in die Rillen eine oder mehrere Heizwendeln 2 eingelegt sein, die entsprechend in Serien- oder Parallelschaltung oder in Einzelschaltung betrieben werden.A bracket 1 for a Heizwendei 2 consists of a z. B. made of magnesite, refractory stone, which is H-shaped in cross section, d. That is, a round or square or rectangular plate 3 has webs 4 in one piece. Grooves 5 are embossed in the surface of the plate. Depending on the desired power levels of the plates, one or more heating coils 2 can be inserted into the grooves, which are operated in series or parallel connection or in individual connection.

Der Boden der Rille 5 besitzt im Abstand von einander angeordnete, durchgehende Löcher oder schlitzförmige Aussparungen 6, durch die im Betrieb von der erhitzten Heizwendel 2 ein Konvektionsluftstrom angesaugt wird, wie dies durch die Pfeile in Fig. 1 angedeutet ist. Durch diesen Konvektionsluftstrom wird die Heizwendel gekühlt, so daß ihre Temperatur um etwa 30-50°C niedriger ist im Vergleich zu einer Ausführungsform gleicher Leistung, jedoch ohne die Löcher oder Aussparungen 6. Zwischen den Wicklungen der Heizwendel 2 sind weitere Löcher oder Aussparungen 7 vorgesehen, durch welche der Konvektionsluftstrom nach unten fallen kann, wenn er Wärme an die Keramikglasplatte 8 abgegeben hat.The bottom of the groove 5 is at a distance of through holes or slot-shaped recesses 6 arranged one above the other, through which a convection air stream is sucked in during operation from the heated heating coil 2, as is indicated by the arrows in FIG. 1. This convection air flow cools the heating coil, so that its temperature is about 30-50 ° C. lower in comparison to an embodiment of the same power, but without the holes or recesses 6. Further holes or recesses 7 are provided between the windings of the heating coil 2 through which the convection air flow can drop when it has given off heat to the ceramic glass plate 8.

Weiterhin ist ein Bügel oder eine Schale 9 vorgesehen, die eine Wärmedämmschicht 10 oder einen Wärmedämmkörper trägt. Auf den Wärmedämmkörper 10 ist eine die Strahlung reflektierende Folie 11, insbesondere eine Aluminiumfolie, aufgelegt. Die Schenkel 4 der Halterung 1 stützen sich einerseits an der Unterseite der Glasplatte 8 und andererseits an der Folie 11 bzw. an der Wärmedämmschicht 10 ab.Furthermore, a bracket or a shell 9 is provided, which carries a heat insulation layer 10 or a heat insulation body. A radiation-reflecting film 11, in particular an aluminum film, is placed on the heat-insulating body 10. The legs 4 of the holder 1 are supported on the one hand on the underside of the glass plate 8 and on the other hand on the film 11 or on the thermal insulation layer 10.

Auf diese Weise entsteht ein Hohlraum, der von der Platte 3 in etwa zwei gleich große Hälften 12a und 12b unterteilt wird. Für eine entsprechende Temperaturregelung kann die Temperatur beispielsweise in dem Hohlraum 12a mittels einer Thermostateinrichtung 13 abgetastet werden, die sich diagonal durch die Anordnung erstreckt.In this way, a cavity is created, which is divided by the plate 3 into approximately two halves 12a and 12b of equal size. For a corresponding temperature control, the temperature can be sensed, for example, in the cavity 12a by means of a thermostat device 13 which extends diagonally through the arrangement.

Da bei der neuen Anordnung die Heizwendel 2 im Abstand von der Platte 8 liegt, trifft ein entsprechend breiter Abschnitt des Strahlungskegels 14 auf die Platte 8, so daß eine gleichmäßige Wärmeabgabe auf das nicht dargestellte, auf die Platte 8 abgestellte Kochgefäß oder eine entsprechende Pfanne erzielt wird und örtliche unerwünschte Überhitzungen ausgeschlossen werden. Weiterhin hält sich dadurch die Belastung der Platte 8 in Grenzen.Since in the new arrangement the heating coil 2 is at a distance from the plate 8, a correspondingly wide section of the radiation cone 14 hits the plate 8, so that a uniform heat emission on the cooking vessel or a corresponding pan, not shown, is achieved and local unwanted overheating is excluded. Furthermore, this keeps the load on the plate 8 within limits.

Die von der Unterseite der Platte 3 nach unten abgestrahlte Wärme wird zum größten Teil durch die Folie 11 zurückgestrahlt. Der Hohlraum 12b hat dabei nun zwei sehr wichtige Funktionen:The heat radiated downward from the underside of the plate 3 is largely radiated back through the film 11. The cavity 12b now has two very important functions:

Würde die Folie 11, z. B. eine Aluminiumfolie, unmittelbar an der Unterseite der Platte 3 angeordnet werden, dann würde sie schmelzen, da dort Temperaturen bis 900°C auftreten können. Der Hohlraum 12b kann dagegen so dimensioniert werden, daß die wärmereflektierende Folie 11 keine Temperatur annimmt, die über ihrer Erweichungstemperatur oder gar Schmelztemperatur liegen würde. Auf der anderen Seite entsteht nun eine entsprechende Luftkonvektion durch die Aussparungen 6, 7, welche für einen entsprechenden Ausgleich sorgt. Die Konvektionsströmung kann sich dabei sehr unterschiedlich ausbilden, je nachdem, welche Temperatur an der Oberseite der Platte herrscht. Im allgemeinen wird die Temperatur an der Platte 8 durch das aufgestellte Koch- oder Bratgut geringer sein als die Temperatur an der Oberfläche der Folie 11. Die abgekühlte Luft fällt dementsprechend durch durch die Aussparungen 7 nach unten und kühlt den Raum 1 2b, wobei sie dann durch andere Aussparungen 6 wieder nach oben steigt. Der Effekt ist besonders ausgeprägt, wenn durch die Temperatursteuerung 13 Stränge der Heizwendel 2 abgeschaltet wurden.Would the film 11, e.g. B. an aluminum foil, be arranged directly on the underside of the plate 3, then it would melt, since temperatures up to 900 ° C can occur. The cavity 12b, on the other hand, can be dimensioned such that the heat-reflecting film 11 does not assume a temperature which would be above its softening temperature or even melting temperature. On the other hand, a corresponding air convection is created through the cutouts 6, 7, which ensures a corresponding compensation. The convection flow can be very different, depending on the temperature at the top of the plate. In general, the temperature on the plate 8 by the cooked or roasted material will be lower than the temperature on the surface of the film 11. The cooled air accordingly falls through the recesses 7 and cools the space 1 2b, then through other recesses 6 rises again. The effect is particularly pronounced when 13 strings of the heating coil 2 have been switched off by the temperature control.

Entsprechende Vergleichsversuche zeigten, daß die Energieübertragung auf das Kochgut bei der neuen Ausführungsform um über 10% im Vergleich zu bekannten Ausführungsformen verbessert wird. Da die Temperatur der Heizwendel bei sonst gleichen Dimensionierungen um ungefähr 50°C abgesenkt werden kann, ergibt sich etwa eine doppelte Lebensdauer der Heizwendel 2 im Vergleich zu anderen Ausführungsformen.Corresponding comparative tests showed that the energy transfer to the food to be cooked in the new embodiment is improved by more than 10% compared to known embodiments. Since the temperature of the heating coil can be reduced by approximately 50 ° C. while the dimensions are otherwise the same, this results in approximately twice the service life of the heating coil 2 in comparison to other embodiments.

Die eingangs genannte Aufgabe, nämlich Absenkung der Temperatur der Heizwendel um 50-100°C bei sonst gleicher Heizleistung wird wesentlich unterstützt, wenn die Halterung 1 aus einem Material hergestellt wird, das bei sehr schlechter elektrischer Leitfähigkeit eine sehr gute Wärmeleitfähigkeit hat. Bevorzugt werden Werte, wie sie durch Magnesiumoxidpreßkörper erreicht werden. Die Halterung soll dementsprechend aus MgO oder aus einer Keramik bestehen, die ähnliche Werte wie ein MgO-Preßkörper besitzt.The task mentioned at the outset, namely lowering the temperature of the heating coil by 50-100 ° C. while the heating output is otherwise the same, is significantly supported if the holder 1 is made from a material which has very good thermal conductivity with very poor electrical conductivity. Values such as those achieved by magnesium oxide pressed bodies are preferred. The holder should accordingly consist of MgO or a ceramic that has values similar to those of an MgO compact.

Claims (3)

1. An electrical heater for ovens or boiling plates, wherein a heatresistant mounting is arranged under a plate which is capable of transmitting radiant heat, in particular a ceramic plate, which mounting carries at least one electrical heating coil, and wherein the mounting is disposed in a space between the glass plate and a heat-barrier layer or a heat-barrier member, wherein the heat-barrier layer is covered by a reflecting foil, characterised in that the mounting has a large number of holes or openings which cause convection of the air enclosed in the space, wherein the heating coil is arranged in a groove (5) in the mounting (1), the bottom of which has a part of the holes or openings (6) so that a convection air flow is sucked in through said openings and passed upwardly through the heated heating coil against the glass plate (8) and that provided between the turns of the heating coil (2) is the other part of the holes or openings (7), through which the convection air flow drops downwardly against the foil (11).
2. A heater according to claim 1 characterised in that the mounting (1) comprises a body of H-shaped cross-section and comprising refractory brick, preferably magnesite, the limb portions (4) of which bear against the underside of the plate (8) and against the heat-carrier layer (10) or the reflective foil (11), white the plate-shaped central web portion (3) of the H-shaped body, which joins the limb portions together, carries the heating coil (2).
3. A heater according to one of claims 1 to 3 characterised in that the mounting (1) for the heating coil (2) comprises a material which, being of poor electrical conductivity, has very good thermal conductivity, namely, in accordance with the values of MgO-pressed members, preferably comprising said material or corresponding ceramics.
EP81101442A 1980-02-29 1981-02-27 Electric heating equipment for ranges or cooking tops Expired EP0035254B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81101442T ATE7254T1 (en) 1980-02-29 1981-02-27 ELECTRICAL HEATING DEVICE FOR COOKERS OR HOT PLATES.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3007806A DE3007806C2 (en) 1980-02-29 1980-02-29 Electric heating devices for stoves and hotplates
DE3007806 1980-02-29

Publications (2)

Publication Number Publication Date
EP0035254A1 EP0035254A1 (en) 1981-09-09
EP0035254B1 true EP0035254B1 (en) 1984-04-25

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EP81101442A Expired EP0035254B1 (en) 1980-02-29 1981-02-27 Electric heating equipment for ranges or cooking tops

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US (1) US4357523A (en)
EP (1) EP0035254B1 (en)
AT (1) ATE7254T1 (en)
DE (2) DE3007806C2 (en)

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Also Published As

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US4357523A (en) 1982-11-02
DE3007806C2 (en) 1982-09-02
EP0035254A1 (en) 1981-09-09
ATE7254T1 (en) 1984-05-15
DE3007806A1 (en) 1981-09-10
DE3163268D1 (en) 1984-05-30

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