EP0071048A1 - Radiant electric heating element and method of manufacturing the same - Google Patents

Radiant electric heating element and method of manufacturing the same Download PDF

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Publication number
EP0071048A1
EP0071048A1 EP82106019A EP82106019A EP0071048A1 EP 0071048 A1 EP0071048 A1 EP 0071048A1 EP 82106019 A EP82106019 A EP 82106019A EP 82106019 A EP82106019 A EP 82106019A EP 0071048 A1 EP0071048 A1 EP 0071048A1
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EP
European Patent Office
Prior art keywords
heating coil
deformations
insulating
radiator according
insulating support
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.)
Granted
Application number
EP82106019A
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German (de)
French (fr)
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EP0071048B1 (en
Inventor
Gerhard Gössler
Eugen Wilde
Bernhard Mikschl
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EGO Elektro Geratebau GmbH
Original Assignee
EGO Elektro Gerate Blanc und Fischer GmbH
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Publication of EP0071048A1 publication Critical patent/EP0071048A1/en
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Publication of EP0071048B1 publication Critical patent/EP0071048B1/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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/017—Manufacturing methods or apparatus for heaters

Definitions

  • the invention relates to an electric heater according to the preamble of claim 1 and a method for its production.
  • the heating conductor consists of a meandering stamped and corrugated band, which has molded protruding tabs that are inserted through a thin insulating support plate and bent under it.
  • the heating conductors made of strips not only have production disadvantages compared to heating coils made of wire because of the punching and the higher waste, but are also more problematic in terms of their durability properties.
  • the object of the invention is to provide an electric radiator which is easy to manufacture and in which the heating coils can be fixed on the insulating support safely and with little risk of thermal overheating.
  • the deformations preferably consist of a one-sided bending of the helix arranged at an axial distance from one another, in particular only one turn being pressed out of the rest of the helix course.
  • the "feet" thus formed lie at an axial distance from one another and are pressed into the otherwise flat or non-profiled surface of the insulating support, while the rest of the heating coil runs practically freely and without being embedded over this surface. This means that the heating coil turns during the pressing process described below Although something can be molded in the surface, which also gives it good lateral support, it should be avoided that the material of the insulating support extends over and surrounds the lower wire of the coil.
  • the surface or surface layer carrying the heating coil is mechanically stronger and more thermally conductive than the rest of the insulating support, preferably by impregnation or curing.
  • the mechanical strengthening improves the holding effect of the "foot" in the insulating support and on the other hand also makes the insulating support less sensitive to transport and assembly.
  • the remaining insulating material can then consist of a less mechanically strong material, which can accordingly have better thermal insulation properties.
  • the somewhat denser surface layer better dissipates the heat from the deformed, embedded part of the coil, so that no heat build-up can occur there, which could lead to the wire burning through overheating.
  • the heating coil arranged in its installation shape in a tool can be provided with deformations in places by means of preferably strip-shaped stamps in accordance with the preferred manufacturing method.
  • the heating coil can then be inserted into a pressing tool part provided with holders for the heating coil in such a way that at least the deformations protrude beyond the surface of the pressing tool part and the insulating material, which may be introduced in loose layers into the pressing tool in individual layers, can be compressed while simultaneously pressing in the deformations .
  • This pressing can take place dry, so that subsequent drying processes are saved.
  • the surface or surface layer carrying the heating coil can preferably be impregnated with a strengthening material, preferably a silica sol.
  • a strengthening material preferably a silica sol.
  • the surface layer to be impregnated can preferably consist of a hydrophilic insulating material and the insulation underneath from a comparatively hydrophobic insulating material.
  • the heating coil itself can generate the heat used for curing during the first test heating, so that it is possible to progressively increase the curing in the vicinity of the heating coils.
  • the electric radiant heater 11 shown in FIGS. 1 and 2 has an insulating support 12 which is arranged in a support shell 13 made of sheet metal.
  • the heater is pressed against the underside of a glass ceramic plate 14 by a spring (not shown).
  • a spring not shown
  • it can also be used to heat other surfaces, for example metal plates or single hot plates.
  • the insulating body 12 consists of two layers, namely an insulating layer 15 made of temperature-resistant and very good insulating material and a surface layer 16 made of a highly heat-resistant insulating material, which is, however, mechanically stronger and has somewhat higher thermal conductivity properties than the insulating layer 15. This mechanically stronger material also forms the raised edge 17 'of the insulating body, which is better protected against injury.
  • a heating coil 18 is arranged on the surface 17 of the insulating support, which is set back from the edge 17 'and thus a bowl-shaped Ver creates depression. It is laid in the form of a double spiral (Fig. 1), so that both connections are easily accessible in the outside area.
  • the heating coils 18 are circular coils made of round resistance wire, which have deformations 19 at a distance from one another, which can be seen from FIGS. 3 to 5. It can be seen there that one turn is pressed out to one side from the normal tubular or cylindrical course of the heating coil, so that it partly lies outside the normal spiral course. The two subsequent turns are pressed together a little.
  • the deformations 19 are arranged such that they give a star-shaped pattern in a top view of the radiator (FIG. 1), as is indicated by the dash-dotted lines 20.
  • the deformations 19 are embedded in the material of the insulating body, specifically in the surface layer 16, that is to say that they are completely surrounded by the insulating material and are thus positively retained in the insulating body.
  • the other and in particular the non-deformed turns of the heating coil 18 lie essentially freely on the surface 17 of the insulating body, whereby, as shown in FIG. 3, they can press somewhat into the surface, but are not completely enclosed by the insulating material, so that they can radiate the heat generated in them well.
  • the heat due to the embedding cannot escape directly from the deformed section 19, at least in the lower part. Some of it is dissipated through the resistance wire by heat conduction. However, the main part is derived from the surface layer 16 by heat conduction. For this purpose, it is advantageous that the deformation of the heating coil is formed by only one turn, because this leads to the dissipation Heat is very low and can be distributed well. However, it would also be possible to form and embed several turns, for example, in the case of heating coils with lower loads.
  • FIG. 6 to 8 show the production of the deformations of the heating coil.
  • a heating coil which is usually produced by winding and then "warping" to the correct length and pitch, is inserted into grooves 21 of a shape 22 which has the double spiral shape shown in FIG. 1.
  • a tool part 23 carries strip-shaped punches 24, which are arranged in a star shape according to lines 20 in FIG. 1. These provided with a rounded cutting edge 24 lie on corresponding recesses 25 in the lower tool part 22. After insertion (Fig. 7), the upper part 23 of the tool is lowered so that the punch 24 penetrate between two turns of the heating coil and this in the from Fig. 3 to 5 deforming manner.
  • the prepared heating coil 18 is inserted with the deformations 19 pointing upwards into a lower pressing tool part 26 and fixed there in the provided spiral shape in grooves 27. Together with a movable pressing tool upper part 28, the pressing tool encloses a shape which corresponds to the finished insulating support. With the upper part of the pressing tool moved out, insulating material in the form of a loose bulk material is introduced into the cavity, which initially still occupies several times the volume of the later insulating body, in layers corresponding to the layering desired later.
  • the insulating material can be constructed, for example, as the base material pyrogenic silica, such as that sold under the trade name Aerosil by Degussa, and can also be opacifiers for absorbing infrared radiation, such as titanium oxide, iron oxide, carbon black or any heat-resistant pigment contain. Ceramic fibers, for example aluminum silicate fibers, can also be used as reinforcing fibers.
  • the lower layer in the form, which later results in the surface layer 16 can have a hardener additive, for example high-melting glass frits, which allow the surface layer to harden when heated. Certain metal oxides can also be used as hardener additives.
  • the insulating body When the mold is closed, the insulating body is compressed to its final shape and the deformations 19 press into the insulating material and are embedded by it, i.e. enclosed or encapsulated.
  • the remaining surface of the spiral acts as a tool surface and has the advantage during the pressing process that the mold can be easily vented if, for example, 27 vent holes 29 are made in the groove base of the groove.
  • the insulating body can preferably be finished pressed in a single operation. However, it is also possible to carry out layer-by-layer pressing if, for example, different layers are to be pressed to different degrees.
  • the body With an insulating body with hardener additive in the surface layer, the body is finished. It is then only cured by heating, for example by applying current to the heating coils 18 on the surface.
  • the mechanically denser and better heat-conducting surface layer 16 can also be produced without post-treatment by appropriate composition of the insulating materials. It is particularly advantageous, however, to remove the surface from the mold with a material act that brings about the desired properties. For example, a silica sol, silicon dioxide in a colloidal form can be sprayed in uniformly. A targeted treatment in the vicinity of the deformations 19 of the heating coils 18 could also take place instead or in addition, for example by arranging spray nozzles at the corresponding fastening points. It is thus possible to achieve the desired mechanical strength and better heat dissipation in fastening areas without otherwise significantly influencing the insulating properties of the insulating support.
  • the surface layer 16 should be hydrophilic, i.e. be water absorbent, as the silica sol is normally suspended in water.
  • the underlying insulating layer 26 should, however, be hydrophobic so that the material cannot penetrate into the insulating layer 15 and reduce the thermal insulating ability.
  • the fumed silica is usually hydrophilic, while the hydrophobic properties of the insulating layer 15 are achieved by a silicone treatment, for example by the addition of silicone groups.
  • Radiators in particular radiant heaters, can largely be produced automatically according to the invention.
  • the deformed heating coil can be provided with all external leads and then the entire insulating body including the fixing can be produced in one operation.
  • the layer-by-layer sequence of different insulation mixtures allows targeted adaptation to the desired application.
  • the top layer should combine high electrical insulation strength with good emissivity.
  • Such a layer then contains, for example, titanium dioxide as an opacifying agent with the addition of Ai 2 0 3 .
  • the deeper layers can then be adjusted for maximum thermal insulation while striving for a low price.
  • the radiator described has the advantage, in particular due to the surface hardening in the entire area not covered by the carrier disk, that it is insensitive to atmospheric moisture and has a very good electrical insulation resistance even when cold.
  • the heating coil can also be produced by a program winding, in which a few turns are still wound normally on a machine and then a turn offset or enlarged is made on one side.
  • the one-sided deformation has the advantage that it is easiest to produce and best meets the thermal and fastening requirements
  • this could also be produced with the corresponding pitch, so that the previously usual warping of the spiral wound on the block is eliminated.
  • the round spiral cross-sectional shape other shapes are also suitable, e.g. an elliptical or flattened shape. Forming from a round wire coil could e.g. take place in the same mold in which the deformation is produced.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Resistance Heating (AREA)
  • Baking, Grill, Roasting (AREA)
  • Surface Heating Bodies (AREA)
  • Control Of Resistance Heating (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Studio Devices (AREA)
  • Measuring Volume Flow (AREA)
  • General Induction Heating (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Cookers (AREA)
  • Ceramic Capacitors (AREA)
  • Inorganic Insulating Materials (AREA)

Abstract

An electrical heating element (18) for heating a plate, e.g. a glass ceramic plate (14) has a multilayer insulating support (12) in whose dish-shaped depression heater coils (18) are arranged in spiral form. The heater coils are located on the insulating support surface (17) and have downwardly directed deformations (19) comprising a turn pressed out in the downwards direction. These deformations (19) are embedded in the surface layer (16) of the insulating support, which is mechanically stronger and more thermally conductive than the underlying insulating layer (15). The deformations are produced in a mould (22, 23) carrying the heater coils in slots (21) and by means of a bladelike punch (24) a turn is pressed into a depression (25). The connection between heater coil (18) and insulating support (12) during the moulding thereof comprises a loose insulating material, the heater coil and deformations being placed in slots (27) of mould part (26).

Description

Die Erfindung betrifft einen elektrischen Heizkörper nach dem Oberbegriff des Anspruchs 1 und ein Verfahren zu seiner Herstellung.The invention relates to an electric heater according to the preamble of claim 1 and a method for its production.

Aus der DE-AS 27 29 929 ist ein elektrischer Heizkörper bekannt geworden, bei dem die Heizwendeln spiralförmig auf einem plattenförmigen Isolierträger dadurch festgelegt sind, daß sie in Abständen in sternförmig verlaufende Erhebungen oder Rippen an der Oberfläche des plattenförmigen Isolierträgers eingebettet sind. Diese Ausführung hat sich sehr bewährt. Sie erfordert jedoch, daß der Isolierträger vor der Festlegung der Heizwendeln vorgepreßt wird, so daß mehrere Arbeitsgänge erforderlich sind.From DE-AS 27 29 929 an electric radiator has become known in which the heating coils are fixed spirally on a plate-shaped insulating support in that they are embedded at intervals in star-shaped elevations or ribs on the surface of the plate-shaped insulating support. This version has proven very successful. However, it requires that the insulating support is pressed before the heating coils are fixed, so that several operations are required.

Aus der DE-OS 23 39 768 ist ein elektrischer Heizkörper bekannt geworden, bei dem die Heizwendel mit haarnadelartig gebogenen Stiften, die in das Isoliermaterial nachträglich hineingesteckt werden, festgehalten werden. Diese Befestigung ist unsicher und sehr arbeitsaufwendig bei der Herstellung.From DE-OS 23 39 768 an electric radiator has become known, in which the heating coil with hairpin-like bent pins, which subsequently in the insulating material to be put in, to be held. This attachment is unsafe and very labor intensive to manufacture.

Aus der US-PS 3 612 828 ist eine ähnliche Befestigung für Heizelemente bekannt geworden, die aus wellenförmig gebogenen Blechstreifen bestehen. Dort werden U-förmig gebogene Blech-oder Drahtbügel durch den Isolierträger gesteckt und mit Klips befestigt.From US-PS 3 612 828 a similar attachment for heating elements is known which consist of corrugated sheet metal strips. There, U-shaped sheet metal or wire brackets are inserted through the insulating support and fastened with clips.

Aus der DE-OS 25 51 137 ist ein Strahlheizkörper bekannt geworden, bei dem der Heizleiter aus einem mäanderförmig gestanzten und gewellten Band besteht, das angeformte vorstehende Lappen besitzt, die durch eine dünne Isolierträgerplatte gesteckt und unter dieser umgebogen werden. Die aus Bändern bestehende Heizleiter haben nicht nur wegen der Stanzung und des höheren Abfalls Produktionsnachteile gegenüber aus Draht bestehenden Heizwendeln, sondern sind auch in ihren Dauerhaltbarkeitseigenschaften problematischer.From DE-OS 25 51 137 a radiant heater has become known in which the heating conductor consists of a meandering stamped and corrugated band, which has molded protruding tabs that are inserted through a thin insulating support plate and bent under it. The heating conductors made of strips not only have production disadvantages compared to heating coils made of wire because of the punching and the higher waste, but are also more problematic in terms of their durability properties.

Aufgabe der Erfindung ist es, einen elektrischen Heizkörper zu schaffen, der leicht herstellbar ist und bei dem die Heizwendeln sicher und mit geringer Gefahr punktueller thermischer überhitzung am Isolierträger festzulegen sind.The object of the invention is to provide an electric radiator which is easy to manufacture and in which the heating coils can be fixed on the insulating support safely and with little risk of thermal overheating.

Diese Aufgabe wird erfindungsgemäß durch das Kennzeichen des Anspruchs 1 gelöst. Die Verformungen bestehen vorzugsweise aus einer in axialem Abstand voneinander angeordneten einseitigen Verbiegung der Wendel, wobei insbesondere jeweils nur eine Windung aus dem übrigen Wendelverlauf herausgedrückt ist. Die dadurch gebildeten "Füßchen" liegen in axialem Abstand voneinander und werden in die im übrigen ebene bzw. unprofilierte Oberfläche des Isolierträgers eingedrückt, während der Rest der Heizwendel praktisch frei und uneingebettet über diese Oberfläche verläuft. Das bedeutet, daß während des nachfolgend noch beschriebenen Preßvorganges die Heizwendel sich zwar etwas in der Oberfläche abformen kann, wodurch sie auch einen guten Seitenhalt bekommt, jedoch sollte vermieden werden, daß das Material des Isolierträgers über den unteren Draht der Wendel herüberreicht und diesen umschließt.This object is achieved by the characterizing part of claim 1. The deformations preferably consist of a one-sided bending of the helix arranged at an axial distance from one another, in particular only one turn being pressed out of the rest of the helix course. The "feet" thus formed lie at an axial distance from one another and are pressed into the otherwise flat or non-profiled surface of the insulating support, while the rest of the heating coil runs practically freely and without being embedded over this surface. This means that the heating coil turns during the pressing process described below Although something can be molded in the surface, which also gives it good lateral support, it should be avoided that the material of the insulating support extends over and surrounds the lower wire of the coil.

Besonders bevorzugt ist eine Ausführungsform, bei der die die Heizwendel tragende Oberfläche bzw. Oberflächenschicht vorzugsweise durch Tränkung oder Aushärtung mechanisch fester und besser wärmeleitend ist als der übrige Isolierträger. Durch die mechanische Verfestigung wird einerseits die Haltewirkung des "Füßchens" im Isolierträger verbessert und andererseits der Isolierträger auch sonst für Transport und Montage unempfindlicher gestaltet. Außerdem kann das übrige Isoliermaterial dann aus einem mechanisch weniger festen Material bestehen, das dementsprechend bessere Wärmeisoliereigenschaften haben kann. Außerdem wird durch die etwas dichtere Oberflächenschicht die Wärme aus dem verformten, eingebetteten Teil der Wendel besser abgeleitet, so daß dort kein Wärmestau entstehen kann, der durch 0berhitzung zum Durchbrennen des Drahtes führen könnte.An embodiment is particularly preferred in which the surface or surface layer carrying the heating coil is mechanically stronger and more thermally conductive than the rest of the insulating support, preferably by impregnation or curing. The mechanical strengthening on the one hand improves the holding effect of the "foot" in the insulating support and on the other hand also makes the insulating support less sensitive to transport and assembly. In addition, the remaining insulating material can then consist of a less mechanically strong material, which can accordingly have better thermal insulation properties. In addition, the somewhat denser surface layer better dissipates the heat from the deformed, embedded part of the coil, so that no heat build-up can occur there, which could lead to the wire burning through overheating.

Zur auch in großen Stückzahlen einfachen Herstellung des elektrischen Heizkörpers kann gemäß dem bevorzugten Herstellungsverfahren die in ihrer Einbaugestalt in einem Werkzeug angeordnete Heizwendel durch vorzugsweise leistenförmige Stempel stellenweise mit Verformungen versehen werden. Die Heizwendel kann dann in ein mit Halterungen für die Heizwendel versehenes Preßwerkzeugteil derart eingelegt werden, daß zumindest die Verformungen über die Fläche des Preßwerkzeugteils hinausragen und das in lockerer Form ggf. in einzelnen Schichten in das Preßwerkzeug eingebrachte Isoliermaterial kann unter gleichzeitiger Einpressung der Verformungen verdichtet werden. Diese Verpressung kann trocken erfolgen, so daß nachfolgende Trocknungsvorgänge eingespart werden.For easy manufacture of the electric radiator even in large quantities, the heating coil arranged in its installation shape in a tool can be provided with deformations in places by means of preferably strip-shaped stamps in accordance with the preferred manufacturing method. The heating coil can then be inserted into a pressing tool part provided with holders for the heating coil in such a way that at least the deformations protrude beyond the surface of the pressing tool part and the insulating material, which may be introduced in loose layers into the pressing tool in individual layers, can be compressed while simultaneously pressing in the deformations . This pressing can take place dry, so that subsequent drying processes are saved.

Nach dem Verpressen kann vorzugsweise die die Heizwendel tragende Oberfläche bzw. Oberflächenschicht mit einem ver- __ festigenden Material, vorzugsweise einem Kieselsol getränkt werden. Dadurch wird die erwähnte mechanisch festere und besser wärmeleitende Oberflächenschicht erzeugt. Um den Bereich der Verfestigung auf die Oberflächenschicht zu beschränken, kann vorzugsweise die zu tränkende Oberflächenschicht aus einem hydrophilen Isoliermaterial und die darunterliegende Isolation aus einem vergleichsweise hydrophoben Isoliermaterial bestehen. Es ist jedoch auch möglich, schon dem Isoliermaterial für die Oberflächenschicht eine aushärtbare Substanz beizufügen, die beispielweise in der Wärme aushärtet. Hier kann beim ersten Probeaufheizen die Heizwendel selbst die Wärme erzeugen, die zum Aushärten dient, so daß es möglich ist, die Aushärtung in der Nähe der Heizwendeln progressiv zu verstärken.After pressing, the surface or surface layer carrying the heating coil can preferably be impregnated with a strengthening material, preferably a silica sol. This creates the above-mentioned mechanically stronger and better heat-conducting surface layer. In order to limit the area of solidification to the surface layer, the surface layer to be impregnated can preferably consist of a hydrophilic insulating material and the insulation underneath from a comparatively hydrophobic insulating material. However, it is also possible to add a curable substance to the insulating material for the surface layer, which substance hardens in the heat, for example. Here, the heating coil itself can generate the heat used for curing during the first test heating, so that it is possible to progressively increase the curing in the vicinity of the heating coils.

Weitere Vorteile und Merkmale der Erfindung gehen aus den Unteransprüchen und der Beschreibung im Zusammenhang mit den Zeichnungen hervor. Ein Ausführungsbeispiel eines Heizkörpers und eine schematische Darstellung des Herstellungsablaufes sind in der Zeichnung dargestellt und werden im folgenden näher erläutert. Es zeigen:

  • Fig. 1 eine schematische Draufsicht auf einen elektrischen Heizkörper,
  • Fig. 2 einen Schnitt durch den Heizkörper und ein Teil einer Glaskeramikplatte
  • Fig. 3 eine starke Vergrößerung des Schnittes im Kreis III in Fig. 2,
  • Fig. 4 eine Seitenansicht einer Heizwendel,
  • Fig. 5 eine perspektivische Darstellung eines Abschnittes der Heizwendel,
  • Fig. 6 ein Detailschnitt durch ein Werkzeug zur Verformung der Heizwendel,
  • Fig. 7 und 8 in der Ebene der Linie VII-VII in Fig. 6 genommene Schnitte in zwei verschiedenen Arbeitsstufen, und
  • Fig. 9 einen Schnitt durch ein Preßwerkzeug, in dem ein Heizkörper verpreßt wird.
Further advantages and features of the invention emerge from the subclaims and the description in connection with the drawings. An embodiment of a radiator and a schematic representation of the manufacturing process are shown in the drawing and are explained in more detail below. Show it:
  • 1 is a schematic plan view of an electric radiator,
  • Fig. 2 shows a section through the radiator and part of a glass ceramic plate
  • 3 shows a large enlargement of the section in circle III in FIG. 2,
  • 4 is a side view of a heating coil,
  • 5 is a perspective view of a portion of the heating coil,
  • 6 shows a detail section through a tool for deforming the heating coil,
  • 7 and 8 in the plane of line VII-VII in Fig. 6 cuts taken in two different stages, and
  • Fig. 9 shows a section through a pressing tool in which a radiator is pressed.

Der in den Figuren 1 und 2 dargestellte elektrische Strahlheizkörper 11 weist einen Isolierträger 12 auf, der in einer Trägerschale 13 aus Blech angeordnet ist. Der Heizkörper ist durch eine nicht dargestellte Feder an die Unterseite einer Glaskeramikplatte 14 angepreßt. Er kann aber auch zur Beheizung anderer Flächen, beispielsweise Metallplatten oder Einzelkochplatten verwendet werden.The electric radiant heater 11 shown in FIGS. 1 and 2 has an insulating support 12 which is arranged in a support shell 13 made of sheet metal. The heater is pressed against the underside of a glass ceramic plate 14 by a spring (not shown). However, it can also be used to heat other surfaces, for example metal plates or single hot plates.

Der Isolierkörper 12 besteht aus zwei Schichten, und zwar einer Isolierschicht 15 aus temperaturbeständigem und sehr gut isolierendem Isoliermaterial und einer Oberflächenschicht 16 aus einem hochwärmebeständigen Isoliermaterial, das jedoch mechanisch fester ist und etwas höhere Wärmeleiteigenschaften hat als die Isolierschicht 15. Dieses mechanisch festere Material bildet auch den hochstehenden Rand17' des Isolierkörpers, der dadurch besser vor Verletzungen geschützt ist.The insulating body 12 consists of two layers, namely an insulating layer 15 made of temperature-resistant and very good insulating material and a surface layer 16 made of a highly heat-resistant insulating material, which is, however, mechanically stronger and has somewhat higher thermal conductivity properties than the insulating layer 15. This mechanically stronger material also forms the raised edge 17 'of the insulating body, which is better protected against injury.

Auf der Oberfläche 17 des Isolierträgers, die gegenüber dem Rand 17' zurückversetzt ist und damit eine schalenförmige Vertiefung schafft, ist eine Heizwendel 18 angeordnet. Sie ist in Form einer Doppelspirale gelegt (Fig. 1), so daß beide Anschlüsse im Außenbereich gut zugänglich sind.On the surface 17 of the insulating support, which is set back from the edge 17 'and thus a bowl-shaped Ver creates depression, a heating coil 18 is arranged. It is laid in the form of a double spiral (Fig. 1), so that both connections are easily accessible in the outside area.

Die Heizwendeln 18 sind kreisrunde Wendeln aus rundem Widerstandsdraht, die in Abständen voneinander Verformungen 19 haben, die aus Fig. 3 bis 5 zu erkennen sind. Es ist dort zu sehen, daß aus dem normalen schlauchartigen oder zylindrisehen Verlauf der Heizwendel jeweils eine Windung nach einer Seite herausgedrückt ist, daß sie z.T. außerhalb des normalen Wendelverlaufes liegt. Dabei werden die beiden anschließenden Windungen etwas zusammengedrückt.The heating coils 18 are circular coils made of round resistance wire, which have deformations 19 at a distance from one another, which can be seen from FIGS. 3 to 5. It can be seen there that one turn is pressed out to one side from the normal tubular or cylindrical course of the heating coil, so that it partly lies outside the normal spiral course. The two subsequent turns are pressed together a little.

Die Verformungen 19 sind so angeordnet, daß sie in Draufsicht auf den Heizkörper (Fig. 1) ein sternförmiges Muster ergeben, wie dies durch die strichpunktierten Linien 20 angedeutet ist. Die Verformungen 19 sind in das Material des Isolierkörpers, und zwar in die Oberflächenschicht 16 eingebettet, d.h., daß sie von dem Isoliermaterial ganz umfaßt werden und somit formschlüssig in dem Isolierkörper festgehalten sind. Die anderen und insbesondere die nicht verformten Windungen der Heizwendel 18 liegen im wesentlichen frei auf der Oberfläche 17 des Isolierkörpers, wobei sie sich, wie Fig. 3 zeigt, etwas in die Oberfläche hineindrücken können, jedoch von dem Isolieimaterial nicht völlig umschlossen werden, so daß sie die in ihnen entstehende Wärme gut abstrahlen können.The deformations 19 are arranged such that they give a star-shaped pattern in a top view of the radiator (FIG. 1), as is indicated by the dash-dotted lines 20. The deformations 19 are embedded in the material of the insulating body, specifically in the surface layer 16, that is to say that they are completely surrounded by the insulating material and are thus positively retained in the insulating body. The other and in particular the non-deformed turns of the heating coil 18 lie essentially freely on the surface 17 of the insulating body, whereby, as shown in FIG. 3, they can press somewhat into the surface, but are not completely enclosed by the insulating material, so that they can radiate the heat generated in them well.

Aus dem verformten Abschnitt 19 kann zumindest im unteren Teil die Wärme infolge der Einbettung nicht direkt entweichen. Ein Teil wird über den Widerstandsdraht durch Wärmeleitung abgeleitet. Der Hauptteil wird jedoch von der Oberflächenschicht 16 durch Wärmeleitung abgeleitet. Dazu ist es vorteilhaft, daß die Verformung der Heizwendel nur von einer Windung gebildet wird, weil dadurch die abzuleitende Wärme sehr gering ist und sich gut verteilen kann. Es wäre jedoch auch möglich, z.B. bei geringer belasteten Heizspiralen mehrere Windungen auszuformen und einzubetten.The heat due to the embedding cannot escape directly from the deformed section 19, at least in the lower part. Some of it is dissipated through the resistance wire by heat conduction. However, the main part is derived from the surface layer 16 by heat conduction. For this purpose, it is advantageous that the deformation of the heating coil is formed by only one turn, because this leads to the dissipation Heat is very low and can be distributed well. However, it would also be possible to form and embed several turns, for example, in the case of heating coils with lower loads.

In den Fig. 6 bis 8 ist die Herstellung der Verformungen der Heizwendel gezeigt. Dazu wird eine üblicherweise durch Wickeln und anschließendes "Verziehen" auf die richtige Länge und Steigung hergestellte Heizwendel in Nuten 21 einer Form 22 eingelegt, die die in Fig. 1 gezeigte Doppelspiralform hat. Ein Werkzeugteil 23 trägt leistenförmige Stempel 24, die entsprechend den Linien 20 in Fig. 1 sternförmig angeordnet sind. Diese mit einer abgerundeten Schneide versehenen Leisten 24 liegen über entsprechende Vertiefungen 25 im Werkzeugunterteil 22. Nach dem Einlegen (Fig. 7) wird das Oberteil 23 des Werkzeugs abgesenkt, so daß die Stempel 24 zwischen zwei Windungen der Heizwendel eindringen und diese in der aus den Fig. 3 bis 5 hervorgehenden Weise verformen.6 to 8 show the production of the deformations of the heating coil. For this purpose, a heating coil, which is usually produced by winding and then "warping" to the correct length and pitch, is inserted into grooves 21 of a shape 22 which has the double spiral shape shown in FIG. 1. A tool part 23 carries strip-shaped punches 24, which are arranged in a star shape according to lines 20 in FIG. 1. These provided with a rounded cutting edge 24 lie on corresponding recesses 25 in the lower tool part 22. After insertion (Fig. 7), the upper part 23 of the tool is lowered so that the punch 24 penetrate between two turns of the heating coil and this in the from Fig. 3 to 5 deforming manner.

Danach wird die vorbereitete Heizwendel 18 jeweils mit den Verformungen 19 nach oben weisend in ein unteres Preßwerkzeugteil 26 eingelegt und dort in der vorgesehenen Spiralform in Nuten 27 festgelegt. Zusammen mit einem bewegbaren Preßwerkzeugoberteil 28 schließt das Preßwerkzeug eine Form ein, die dem fertigen Isolierträger entspricht. In den Hohlraum wird bei herausgefahrenem Preßwerkzeugoberteil 28 Isoliermaterial in Form eines losen Schüttgutes eingebracht, das anfänglich noch das mehrfache Volumen des späteren Isolierkörpers einnimmt, und zwar in Schichten entsprechend der später gewünschten Schichtung. Das Isoliermaterial kann beispielsweise als Basismaterial pyrogene Kieselsäure, wie sie z.B. unter dem Handelsnamen Aerosil von der Firma Degussa vertrieben wird, aufgebaut sein und ferner Trübungsmittel zur Absorption der Infrarotstrahlung wie z.B. Titanoxid, Eisenoxid, Ruß oder irgendein wärmebeständiges Pigment enthalten. Ferner können als Verstärkungsfasern keramische Fasern, z.B. Aluminiumsilikatfasern verwendet werden. Insbesondere die in der Form untere Schicht, die später die Oberflächenschicht 16 ergibt, kann einen Härterzusatz aufweisen, beispielsweise hochschmelzende Glasfritten, die eine Aushärtung der Oberflächenschicht bei Erwärmung ermöglichen. Auch gewisse Metalloxide können als Härterzusatz verwendet werden.Thereafter, the prepared heating coil 18 is inserted with the deformations 19 pointing upwards into a lower pressing tool part 26 and fixed there in the provided spiral shape in grooves 27. Together with a movable pressing tool upper part 28, the pressing tool encloses a shape which corresponds to the finished insulating support. With the upper part of the pressing tool moved out, insulating material in the form of a loose bulk material is introduced into the cavity, which initially still occupies several times the volume of the later insulating body, in layers corresponding to the layering desired later. The insulating material can be constructed, for example, as the base material pyrogenic silica, such as that sold under the trade name Aerosil by Degussa, and can also be opacifiers for absorbing infrared radiation, such as titanium oxide, iron oxide, carbon black or any heat-resistant pigment contain. Ceramic fibers, for example aluminum silicate fibers, can also be used as reinforcing fibers. In particular, the lower layer in the form, which later results in the surface layer 16, can have a hardener additive, for example high-melting glass frits, which allow the surface layer to harden when heated. Certain metal oxides can also be used as hardener additives.

Beim Schließen der Form wird der Isolierkörper auf seine endgültige Form verdichtet und dabei drücken sich die Verformungen 19 in das Isoliermaterial hinein und werden von diesem eingebettet, d.h. umschlossen bzw. umpreßt. Die restliche Oberfläche der Spirale wirkt als Werkzeugoberfläche und hat beim Preßvorgang noch den Vorteil, daß es die leichte Entlüftung der Form ermöglicht, wenn beispielsweise im Nutgrund der Nut 27 Entlüftungsbohrungen 29 angebracht werden. Vorzugsweise kann der Isolierkörper trotz eines mehrschichtigen Aufbaus, der durch das Einschütten mehrerer Lagen von unterschiedlichen Isoliermaterialien erreicht wird, in einem einzigen Arbeitsgang fertiggepreßt werden. Es ist jedoch auch möglich, eine lagenweise Verpressung vorzunehmen, wenn beispielsweise unterschiedliche Lagen unterschiedlich stark gepreßt werden sollen.When the mold is closed, the insulating body is compressed to its final shape and the deformations 19 press into the insulating material and are embedded by it, i.e. enclosed or encapsulated. The remaining surface of the spiral acts as a tool surface and has the advantage during the pressing process that the mold can be easily vented if, for example, 27 vent holes 29 are made in the groove base of the groove. In spite of a multilayer structure which is achieved by pouring several layers of different insulating materials, the insulating body can preferably be finished pressed in a single operation. However, it is also possible to carry out layer-by-layer pressing if, for example, different layers are to be pressed to different degrees.

Bei einem Isolierkörper mit Härterzusatz in der Oberflächenschicht ist damit der Körper fertiggestellt. Er wird dann nur noch durch Erwärmung, beispielweise durch Strombeaufschlagung der Heizwendeln 18 an der Oberfläche ausgehärtet. Die mechanisch dichtere und besser wärmeleitende Oberflächenschicht 16 läßt sich auch durch entsprechende Zusammensetzung der Isoliermaterialienohne Nachbehandlung herstellen. Besonders vorteilhaft ist es jedoch, nach dem Entnehmen des Preßlings aus der Form die Oberfläche mit einem Material zu behandeln, das die gewünschten Eigenschaften herbeiführt. Es kann beispielsweise ein Kieselsol, Siliciumdioxid in kolloidaler Form gleichmäßig eingesprüht werden. Es könnte auch statt dessen bzw. zusätzlich eine gezielte Behandlung in der Umgebung der Verformungen 19 der Heizwendeln 18 erfolgen, indem beispielsweise Sprühdüsen an den entsprechenden Befestigungsstellen angeordnet sind. Es ist somit möglich, die gewünschte mechanische Festigkeit und bessere Wärmeableitung in Befestigungsbereiche zu erreichen, ohne die Isoliereigenschaften des Isolierträgers im übrigen wesentlich zu beeinflussen.With an insulating body with hardener additive in the surface layer, the body is finished. It is then only cured by heating, for example by applying current to the heating coils 18 on the surface. The mechanically denser and better heat-conducting surface layer 16 can also be produced without post-treatment by appropriate composition of the insulating materials. It is particularly advantageous, however, to remove the surface from the mold with a material act that brings about the desired properties. For example, a silica sol, silicon dioxide in a colloidal form can be sprayed in uniformly. A targeted treatment in the vicinity of the deformations 19 of the heating coils 18 could also take place instead or in addition, for example by arranging spray nozzles at the corresponding fastening points. It is thus possible to achieve the desired mechanical strength and better heat dissipation in fastening areas without otherwise significantly influencing the insulating properties of the insulating support.

Um eine gute Verteilung des Tränkungsmaterials zu erreichen, ohne daß dieses zu tief eindringt, sollte die Oberflächenschicht 16 hydrophil, d.h. wasseraufsaugend sein, da das Kieselsol normalerweise in Wasser aufgeschwemmt ist. Die darunterliegende Isolierschicht 26 sollte jedoch hydrophob sein, damit das Material nicht in die Isolierschicht 15 eindringen kann und die thermische Isolierfähigkeit vermindert. Die pyrogene Kieselsäure ist, normalerweise hyrophil, während die hydrophoben Eigenschaften der Isolierschicht 15 durch eine Silikonbehandlung, beispielsweise durch Anlagerung von Silikongruppen, erreicht wird.In order to achieve a good distribution of the impregnation material without penetrating it too deeply, the surface layer 16 should be hydrophilic, i.e. be water absorbent, as the silica sol is normally suspended in water. The underlying insulating layer 26 should, however, be hydrophobic so that the material cannot penetrate into the insulating layer 15 and reduce the thermal insulating ability. The fumed silica is usually hydrophilic, while the hydrophobic properties of the insulating layer 15 are achieved by a silicone treatment, for example by the addition of silicone groups.

Beim Verpressen, insbesondere beim gemeinsamen Verpressen verschiedener Lagen, kommt es zu einer innigen Verbindung, so daß sich diese Schichten nicht voneinander trennen.When pressing, in particular when pressing different layers together, there is an intimate connection so that these layers do not separate from one another.

Heizkörper, insbesondere Strahlheizkörper können nach der Erfindung weitgehend automatisch hergestellt werden. Die verformte Heizwendel kann mit sämtlichen äußeren Zuleitungen versehen werden und danach der gesamte Isolierkörper einschl. der Festlegung in einem Arbeitsgang hergestellt werden. Die schichtweise Folge verschiedener Isoliermischungen erlaubt eine gezielte Anpassung an den gewünschten Anwendungsfall. Z.B. sollte die oberste Schicht eine hohe elektrische Isolierfestigkeit mit einer guten Emissionsfähigkeit verbinden. Eine solche Schicht enthält dann z.B. Titandioxid als Trübungsmittel unter Zusatz von Ai203. Die tieferen Schichten können dann auf höchste thermische Isolierfähigkeit unter gleichzeitiger Anstrebung eines niedrigen Preises eingestellt werden.Radiators, in particular radiant heaters, can largely be produced automatically according to the invention. The deformed heating coil can be provided with all external leads and then the entire insulating body including the fixing can be produced in one operation. The layer-by-layer sequence of different insulation mixtures allows targeted adaptation to the desired application. For example, the top layer should combine high electrical insulation strength with good emissivity. Such a layer then contains, for example, titanium dioxide as an opacifying agent with the addition of Ai 2 0 3 . The deeper layers can then be adjusted for maximum thermal insulation while striving for a low price.

Der beschriebene Heizkörper hat, insbesondere durch die Oberflächenverfestigung in dem gesamten, nicht von der Trägerscheibe abgedeckten Bereich den Vorteil, daß er unempfindlich gegen Luftfeuchtigkeit ist und auch im kalten Zustand einen sehr guten elektrischen Isolationswiderstand aufweist. Die Heizwendel kann außer durch das beschriebene Werkzeug auch durch eine Programmwicklung erzeugt werden, indem auf einer Maschine jeweils einige Windungen noch normal gewickelt werden und danach eine einseitig versetzte oder auch vergrößerte Windung gemacht wird. Obwohl die einseitige Verformung den Vorteil hat, daß sie am einfachsten herstellbar ist und den wärmetechnischen und Befestigungsanforderungen am besten entspricht, ist es auch möglich, den Vorsprung in Form einer umlaufenden Windung mit größerem Durchmesser herzustellen oder beispielsweise die Verformung nur nach einer Seite herauszuziehen, den übrigen Teil der Windung jedoch in der Gesamtgestalt der Wendel zu lassen, so daß die verformte Windung dann eine nierenförmige Gestalt hat. Bei der Programmwicklung der Heizwendel könnte diese auch gleich mit der entsprechenden Steigung hergestellt werden, so daß das bisher übliche Verziehen der auf Block gewickelten Spirale entfällt. Statt der runden Wendel-Querschnittsform eignen sich auch andere Formen, z.B. eine elliptische oder abgeflachte Form. Die Formung aus einer runden Drahtwendel könnte z.B. im gleichen Formwerkzeug erfolgen, in dem die Verformung hergestellt wird.The radiator described has the advantage, in particular due to the surface hardening in the entire area not covered by the carrier disk, that it is insensitive to atmospheric moisture and has a very good electrical insulation resistance even when cold. In addition to the tool described, the heating coil can also be produced by a program winding, in which a few turns are still wound normally on a machine and then a turn offset or enlarged is made on one side. Although the one-sided deformation has the advantage that it is easiest to produce and best meets the thermal and fastening requirements, it is also possible to produce the projection in the form of a circumferential turn with a larger diameter or, for example, to pull the deformation out only on one side to leave the remaining part of the turn in the overall shape of the helix, so that the deformed turn then has a kidney-shaped shape. In the program winding of the heating coil, this could also be produced with the corresponding pitch, so that the previously usual warping of the spiral wound on the block is eliminated. Instead of the round spiral cross-sectional shape, other shapes are also suitable, e.g. an elliptical or flattened shape. Forming from a round wire coil could e.g. take place in the same mold in which the deformation is produced.

Claims (12)

1. Elektrischer Heizkörper für die Beheizung einer Platte (14), z.B. einer Glaskeramik-Kochplatte, mit einem Isolierträger (12), auf dem durch stellenweise Einbettung in das Material des Isolierkörpers eine Heizwendel (18) festgelegt ist und im übrigen zwischen den in Längsabstand der Heizwendel voneinander angeordneten Befestigungsstellen im wesentlichen frei verläuft, dadurch gekennzeichnet, daß die Heizwendel (18) stellenweise vorstehende Verformungen (19) aufweist, die in das Material des Isolierkörpers (12) eingebettet sind.1. Electric radiator for heating a plate (14), e.g. a glass ceramic hotplate, with an insulating support (12), on which a heating coil (18) is fixed by embedding it in places in the material of the insulating body and, in addition, essentially runs freely between the fastening points arranged at a longitudinal distance from the heating coil, characterized in that the heating coil (18) has protruding deformations (19) in places, which are embedded in the material of the insulating body (12). 2. Heizkörper nach Anspruch 1, dadurch gekennzeichnet, daß die Verformungen (19) aus einer in axialem Abstand voneinander angeordneten einseitigen Verbiegungen in der Wendel bestehen.2. Radiator according to claim 1, characterized in that the deformations (19) consist of an axially spaced one-sided bends in the coil. 3. Heizkörper nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Verformungen (19) jeweils aus nur einer aus dem übrigen Wendelverlauf herausgedrückten Windung bestehen.3. Radiator according to claim 1 or 2, characterized in that the deformations (19) each consist of only one turn pressed out from the rest of the spiral course. 4. Heizkörper nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Verformungen (19) derart angeordnet sind, daß sie bei einer spiralähnlichen Anordnung der Heizwendel (18) auf dem Isolierträger (12) im wesentlichen sternförmig liegen.4. Radiator according to one of the preceding claims, characterized in that the deformations (19) are arranged such that they are substantially star-shaped in a spiral-like arrangement of the heating coil (18) on the insulating support (12). 5. Heizkörper nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Isolierträger (12) aus mehreren miteinander verpreßten Isolierschichten (15, 16) besteht.5. Radiator according to one of the preceding claims, characterized in that the insulating support (12) consists of a plurality of insulating layers (15, 16) pressed together. 6. Heizkörper nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die die Heizwendel (18) tragende Oberfläche (17) bzw. Oberflächenschicht (16) vorzugsweise durch Tränkung oder Aushärtung mechanisch fester und besser wärmeleitend ist als der übrige Isolierträger.6. Radiator according to one of the preceding claims, characterized in that the heating coil (18) carrying surface (17) or surface layer (16) is preferably mechanically stronger and better heat-conducting than the rest of the insulating support by impregnation or curing. 7. Heizkörper nach Anspruch 6, dadurch gekennzeichnet, daß die mechanische Verfestigung vorwiegend im Bereich der Einbettung der Verformungen (19) vorgesehen ist.7. Radiator according to claim 6, characterized in that the mechanical solidification is provided primarily in the region of the embedding of the deformations (19). 8. Heizkörper nach Anspruch 6 oder 7, dadurch gekennzeichnet, daß die zu tränkende Oberflächenschicht (16) aus einem hydrophilen Isoliermaterial und die darunterliegende Isolierschicht (15) aus einem vergleichsweise hydrophoben Isoliermaterial besteht.8. Radiator according to claim 6 or 7, characterized in that the surface layer to be impregnated (16) consists of a hydrophilic insulating material and the underlying insulating layer (15) consists of a comparatively hydrophobic insulating material. 9. Heizkörper nach Anspruch 6 oder 7, dadurch gekennzeichnet, daß die Oberfläche (17) bzw. Oberflächenschicht (16) im Bereich der Heizwendel (18) und insbesondere ihrer Einbettung ein durch Wärme aushärtbares Material enthält.9. Radiator according to claim 6 or 7, characterized in that the surface (17) or surface layer (16) in the region of the heating coil (18) and in particular their embedding contains a heat-curable material. 10. Verfahren zur Herstellung des Heizkörpers nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die in ihrer Einbaugestalt in einem Werkzeug (22, 23) angeordnete Heizwendel (18) durch vorzugsweise leistenförmige Stempel (24) stellenweise mit Verformungen (19) versehen wird, die Heizwendel (18) in ein mit Halterungen (27) für die Heizwendel (18) versehenes Preßwerkzeugteil (26) derart eingelegt wird, daß zumindest die Verformungen (19) über die Fläche des Preßwerkzeugteils (26) hinausragen und daß das in lockerer Form ggf. in einzelnen Schichten in das Preßwerkzeug eingebrachte Isoliermaterial unter gleichzeitiger Einpressung der Verformungen (19) in die Oberfläche (17) des entstehenden Isolierkörpers (12) verdichtet wird.10. A method for producing the radiator according to one of the preceding claims, characterized in that the heating coil (18) arranged in its installation shape in a tool (22, 23) is provided with deformations (19) in places by preferably strip-shaped stamps (24), the heating coil (18) is inserted into a press tool part (26) provided with holders (27) for the heating coil (18) in such a way that at least the deformations (19) protrude beyond the surface of the press tool part (26) and that this may be in a loose form insulating material introduced into the pressing tool in individual layers while simultaneously compressing the deformations (19) into the surface (17) of the resulting insulating body (12). 11. Verfahren nach Anspruch 10, dadurch gekennzeichnet, daß die die Heizwendel (18) tragende Oberfläche (17) bzw. Oberflächenschicht (16) nach dem Verpressen mit einem verfestigenden Material, vorzugsweise einem Kieselsol, getränkt wird.11. The method according to claim 10, characterized in that the heating coil (18) bearing surface (17) or surface layer (16) after pressing with a solidifying material, preferably a silica sol, is soaked. 12. Verfahren nach Anspruch 10, dadurch gekennzeichnet, daß eine Aushärtung der mit einem aushärtbaren Material versetzten Oberfläche (17) bzw. Oberflächenschicht (16) durch die Erwärmung der Heizwendel (18) selbst erfolgt.12. The method according to claim 10, characterized in that a hardening of the surface with a hardenable material (17) or surface layer (16) is carried out by heating the heating coil (18) itself.
EP82106019A 1981-07-24 1982-07-06 Radiant electric heating element and method of manufacturing the same Expired EP0071048B1 (en)

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DE19813129239 DE3129239A1 (en) 1981-07-24 1981-07-24 ELECTRIC RADIATOR FOR HEATING A PLATE AND METHOD FOR THE PRODUCTION THEREOF

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US6194689B1 (en) 1998-05-11 2001-02-27 Emerson Electric Co. Radiant heater element for use in grill and the like
US9952160B2 (en) 2014-04-04 2018-04-24 Packaging Corporation Of America System and method for determining an impact of manufacturing processes on the caliper of a sheet material
WO2018200928A2 (en) 2017-04-28 2018-11-01 Corning Incorporated Edge directors including an interior heating device
ES2714427A1 (en) * 2017-11-28 2019-05-28 Bsh Electrodomesticos Espana Sa COOKING FIELD DEVICE (Machine-translation by Google Translate, not legally binding)
US20210041108A1 (en) * 2019-08-09 2021-02-11 Eidon, Llc Apparatuses for radiant heating

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DE2740163A1 (en) * 1977-03-09 1978-09-14 Emerson Electric Co HEATING ELEMENT WITH OPEN HEATING COIL
DE2820138A1 (en) * 1978-05-09 1979-11-15 Karl Fischer Electric element for glass ceramic cooker plate - is partly embedded in raised portions of insulating base

Cited By (10)

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Publication number Priority date Publication date Assignee Title
EP0189108B1 (en) * 1985-01-25 1991-07-10 Ceramaspeed Limited Heating device, especially for a cooking plate heated by radiation, and its manufacturing process
EP0210575A1 (en) * 1985-07-31 1987-02-04 E.G.O. Elektro-Geräte Blanc u. Fischer Electrical radiant heating element for heating hot plates, and process and device for its manufacture
EP0234373A2 (en) * 1986-02-26 1987-09-02 E.G.O. Elektro-Geräte Blanc u. Fischer Cooking unit with radiant heating element
EP0234373A3 (en) * 1986-02-26 1988-03-02 E.G.O. Elektro-Geräte Blanc u. Fischer Cooking unit with radiant heating element
EP0355388A1 (en) * 1988-08-19 1990-02-28 E.G.O. Elektro-Geräte Blanc u. Fischer Radiant heater and method and device for producing same
US5048176A (en) * 1988-08-19 1991-09-17 E.G.O. Elektro-Gerate Blanc U. Fischer Method of making a radiant heater
US5196678A (en) * 1988-08-19 1993-03-23 E.G.O. Elektro-Gerate Blanc U. Fischer Radiant heater, as well as method and apparatus for its production
EP0625865A2 (en) * 1993-05-21 1994-11-23 Ceramaspeed Limited Method of manufacturing a radiant electric heater
EP0625865A3 (en) * 1993-05-21 1995-01-11 Ceramaspeed Ltd Method of manufacturing a radiant electric heater.
US5477605A (en) * 1993-05-21 1995-12-26 Ceramaspeed Limited Method of manufacturing a radiant electric heater

Also Published As

Publication number Publication date
ZA825038B (en) 1983-04-27
NO154679C (en) 1986-11-26
YU158082A (en) 1985-03-20
ES274609Y (en) 1985-01-01
GR76857B (en) 1984-09-04
YU43961B (en) 1989-12-31
DE3129239A1 (en) 1983-02-10
ES274609U (en) 1984-05-16
AU557733B2 (en) 1987-01-08
US4471214A (en) 1984-09-11
AU8621582A (en) 1983-01-27
FI75465C (en) 1988-06-09
ATE11449T1 (en) 1985-02-15
FI822565L (en) 1983-01-25
EP0071048B1 (en) 1985-01-23
DE3262043D1 (en) 1985-03-07
NO822532L (en) 1983-01-25
FI822565A0 (en) 1982-07-20
FI75465B (en) 1988-02-29
NO154679B (en) 1986-08-18
JPS5826485A (en) 1983-02-16
JPH0449231B2 (en) 1992-08-10

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