EP1602262A1 - Dispositif de chauffage electrique a plaque chauffante a contact - Google Patents

Dispositif de chauffage electrique a plaque chauffante a contact

Info

Publication number
EP1602262A1
EP1602262A1 EP04716592A EP04716592A EP1602262A1 EP 1602262 A1 EP1602262 A1 EP 1602262A1 EP 04716592 A EP04716592 A EP 04716592A EP 04716592 A EP04716592 A EP 04716592A EP 1602262 A1 EP1602262 A1 EP 1602262A1
Authority
EP
European Patent Office
Prior art keywords
heater
hotplate
heating
iron
contact
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.)
Withdrawn
Application number
EP04716592A
Other languages
German (de)
English (en)
Inventor
Wolfgang Thimm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EGO Elektro Geratebau GmbH
Original Assignee
EGO Elektro Geratebau GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by EGO Elektro Geratebau GmbH filed Critical EGO Elektro Geratebau GmbH
Publication of EP1602262A1 publication Critical patent/EP1602262A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • 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
    • 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
    • H05B2203/02—Heaters using heating elements having a positive temperature coefficient

Definitions

  • the invention relates to an electric heater with a contact hotplate with the features of the preamble of claim 1.
  • the invention has for its object to provide a heater mentioned at the outset with which the disadvantages of the prior art can be avoided and in particular an additional temperature limiter with opening electrical contacts can be dispensed with.
  • the heater with the contact hotplate has at least one wire-shaped or wire-like heater for heating the contact hotplate.
  • the heater consists of a metallic material with PTC properties.
  • the advantage of a heater made of PTC material for a contact hotplate is that above a certain temperature, which roughly corresponds to a limit temperature that should not be exceeded in normal operation, the electrical resistance of the heater increases sharply. This reduces the current flow accordingly and the heating output drops. The lowering of the heating power in turn causes a return to the operating temperature range.
  • the use of a heater made of such a PTC material has the advantage that it is not just a pure securing element.
  • the heater is self-limiting in addition to its property as a heating element, so it combines two properties.
  • the heater can either consist of a so-called iron-based alloy, which maintains a cubic, inner-centered crystal structure during all operating states of the heater. All operating states of the heater are understood to mean different temperatures at which the heater is operated as intended. In the case of contact hotplates, these are usually temperatures up to a few hundred degrees, for example up to 300 ° C or 400 ° C.
  • the maintaining The special crystal structure has the advantage that a phase transition from ⁇ -iron to ⁇ -iron is avoided during normal operation. This way the heater has a better durability. Above all, however, it is possible to obtain PTC properties in addition to raising a Curie temperature of the material, which can be set relatively precisely in a desired range. Such a material is described for example in EP 1213540 A2, to which reference is expressly made here.
  • the heater can consist of a cobalt-iron alloy as a metallic material with PTC properties, which contains, for example, approximately 70% cobalt-iron.
  • a cobalt-iron alloy as a metallic material with PTC properties, which contains, for example, approximately 70% cobalt-iron.
  • Such a material is available, for example, under the name CF25 from Vacuumschmelze.
  • the heater can also be made of a tungsten alloy or a molybdenum alloy. Such alloys are known for use in halogen lamps or light bulbs.
  • a temperature-resistance coefficient greater than 6 is preferably provided, so that the temperature rise is relatively strong from the desired temperature limit range. Larger values above 8 can also be selected, for example 10.
  • an iron-based alloy can be characterized in that it contains vanadium.
  • the vanadium content can be 1 to 3 or 4% by weight, for example approx. 1.5% by weight.
  • Other alloys can contain a small proportion of molybdenum, for example up to 4% by weight. It can also contain 1 to 4% by weight of titanium.
  • the arrangement of the heater on the contact hotplate can be such that it is arranged on its underside for heating it.
  • a con- tact should be as flat as possible or ensure the best possible heat transfer.
  • a heater according to the invention in a tube, for example in a coiled form. It should be covered with insulation, for example quartz sand, ceramic or the like.
  • This tube in turn can be placed on the underside of the contact hotplate, for which purpose it is advantageously flattened to increase the contact area.
  • the heater may be surrounded by insulation in an airtight manner.
  • insulation can be based on glass or ceramic and should accordingly be temperature-stable. It can also be polymer ceramics.
  • the insulation is arranged here with the heater on the underside of the contact hotplate. It is also conceivable to provide an evacuated insulation within which the heater runs.
  • a heater or a contact hotplate can have several wire-shaped heaters, for example two or three. At least one of the heaters, in particular exactly one heater, advantageously consists of an iron-based alloy mentioned above. So part of the available heating power is self-regulating, which can either have a direct effect on the other heaters or over the entire heat input onto the contact hotplate.
  • a heater made of the aforementioned iron-based alloy with at least one conventional heater, which can also consist of wire made of conventional resistance material, in series. Overheating the heater with the PTC effect then causes the entire branch to be throttled or switched off, and thus also the conventional one Heater.
  • a conventional heater or the like can be, for example, an FeCrAI alloy. exhibit. Such a heating conductor is described in EP 542128 A1, to which reference is expressly made here.
  • a parallel connection of a heater with an aforementioned iron-based alloy and a conventional heater there can be a parallel connection of a heater with an aforementioned iron-based alloy and a conventional heater.
  • the heater regulates itself or only its own branch.
  • the heaters in particular in the aforementioned possible wirings, can be provided in several separate branches.
  • a heater made of an iron base alloy mentioned above should be provided in at least one of the branches. It is possible to apply electrical energy to all branches together.
  • the individual branches can run in so-called defined surface areas, which can surround and adjoin one another, but essentially do not overlap or penetrate. The surface areas are advantageously adapted to the shape of the contact hotplate, for example round and concentric with one another.
  • any switching device which can produce different circuits can be used to connect such branches to several heaters. These can be serial and / or parallel, wherein several branches can be interconnected in completely free wiring and supplied with electrical energy. Different branches can be interconnected in different ways. Depending on the type of wiring, they can be supplied with different amounts of energy. This is especially true when such a contact plate according to the invention is similar to a conventional hotplate with several heating circuits on a voltage source is connected and either clocked or the power can be set by the type of connection.
  • a contact hotplate can be a so-called cast hotplate, as is common.
  • the heater or heaters can run between ribs which are molded onto the underside of the cast-iron hotplate. As described above, the heaters can run in an insulation and, under certain circumstances, also in the form of a tubular heater.
  • the heater has a flat wire shape and is attached to the underside of the ceramic with good heat conduction, preferably flat.
  • a flat wire shape can extend up to a wide foil shape in order to create a balanced relationship between heater area, heater cross-section and heater output.
  • FIG. 1 is a side view of a ceramic plate with flat heaters
  • FIG. 2 is a plan view of the underside of the ceramic plate from FIG. 1,
  • FIGS. 5 and 6 wiring examples for several heating conductors.
  • a heater 11 is shown from the side.
  • This has a contact hotplate 12, which can consist, for example, of a ceramic material.
  • a ceramic hotplate is known for example from EP 069 298 A1.
  • Heating conductors 14 are arranged on the underside of the hotplate 12. The course of the heating conductor 14 is particularly clear from Figure 2. It can be seen here how, starting from connections 15, a heating conductor 14 is applied as a continuous band in double spiral shape to the underside of the hotplate 12.
  • the heating conductor 14 is divided into several different areas, which can basically be divided into two types.
  • the heating conductor regions 14a are formed from so-called normal or conventional heating conductor material, for example a FeCrAI alloy.
  • Heater regions 14b which together as the heater regions 14a form the entire, continuous heat conductor 14 as short pieces, are made of the metallic material according to the invention with PTC
  • the heating conductor regions 14a and 14b are connected to one another in such a way that there are no disturbing contact resistances and also no other boundary layer problems.
  • heating conductor 14 There are various options for applying the heating conductor 14. On the one hand, it is possible to produce a continuous band, for example in the form of flat wire, from the heating conductor regions 14a and 14b by joining them together. This can be attached to the underside of the hotplate 12 in almost any manner, for example by gluing or embedding using ceramic adhesive. Alternatively, it is conceivable to produce so-called thick-film pastes from the respective materials and to melt them onto the hotplate 12.
  • a heater 111 is shown in section with a cast hotplate 112 on which a cooking vessel stands.
  • the cast hotplate 112 has, according to known designs, concentric projecting ribs 118 on the underside. In each of the spaces formed by these ribs 118, a heating conductor 114 is embedded in a spiral shape by means of the insulating embedding 117.
  • a further heater 211 is shown in FIG.
  • a heating conductor 214 is also provided there in a coiled form. However, here the heating conductor 214 is embedded in a tube 216 together with an insulating embedding 217. Tube 216 and heating conductor 214 form a so-called tubular heating element and are approximately triangular in cross section here. This makes it possible to ensure a larger direct contact surface for heat transfer to a hotplate 212 located above. Methods for deforming a tube 216 into such a triangular shape are known to the person skilled in the art.
  • the tube 216 is advantageously surrounded on the underside of the hotplate 212 with a thermal insulation or the like, which particularly preferably has a certain reflective effect upwards. As a result, a large part of the heat generated by the tube 216 or the hot conductor 214 can be directed upwards to the hotplate 212.
  • the tube 216 can either be attached to the underside of the hotplate 212 by means of glue or the like, for example as described above, it advantageously also providing good heat transfer here.
  • glue or the like for example as described above
  • Further possibilities can, for example, be to solder or bond the tube 216 to the underside of the hotplate 212, since the heating conductor 214 is electrically insulated from it. Such metallic transitions would additionally improve the heat transfer if the hotplate 212 were made metallic.
  • FIGS. 5 and 6 show possible types of interconnection of heating conductors 314a and 414a made from conventional heating conductor material and heating conductors 314b and 414b made from an iron-based alloy according to the invention. As can be seen, these can be connected in parallel, in series or in a mixed manner with one another in various ways.
  • the heat conductors made of an iron-based alloy according to the invention have a PTC characteristic. This means that their specific electrical resistance increases sharply from a temperature of approx. 300 ° C and can more than double, for example up to 600 ° C. As described at the beginning, the increase in the electrical see resistance of a heating conductor the current flow through it is lower. This reduces the heat output, which in turn causes the resistance to drop due to the decreasing temperature.
  • heating conductors so to speak, can be used in various ways.
  • the heating conductors described here should primarily be used as heating conductors and not only as overtemperature protection devices.
  • FIG. 5 shows a parallel connection of two, so to speak, conventional heating conductors 314a.
  • a heating conductor 314b made of an iron-based alloy is connected upstream of these.
  • the heating conductors 314a and 314b are, for example, attached to a contact hotplate for heating in the manner described above.
  • heating conductors shown which are jointly supplied with voltage
  • further heating conductors can be attached to the same contact hotplate.
  • a separately switchable two-circuit radiator could be created.
  • the heating conductor 314b heats because of the relatively uniform temperature distribution in the hotplate. This increases its electrical resistance due to the properties of the iron-based alloy used, which in turn causes a reduction in the current flowing through it. This means that less current flows through the conventional heating conductor 314a. This reduces their heating output and overall the heating of the hotplate. The temperature drops until the current flow through the heating conductor 314b increases again and thus also the heating power. Thus, the heating conductor 314b does not regulate only itself, but also the conventional heating conductor 314a. Furthermore, he himself contributes to heating the hotplate.
  • the heating conductors in particular the hot conductor 314b, it is possible to achieve a so-called steady state.
  • the temperature and electrical resistance and thus the heating output remain approximately the same.
  • FIG. 6 shows a parallel connection of a conventional heating conductor 414a and a heating conductor 414b according to the invention with an iron-based alloy. Both heating conductors 414 are connected to the supply voltage. In the case of overtemperature, it is easy to see that only the heating conductor 414b reduces its output. The heating conductor 414a remains unaffected by this and continues to heat normally.
  • the heating conductor 414b according to the invention regulates itself only.
  • the total heat generation is reduced, but only by reducing the heat generation by the iron-based alloy heating conductor 414b according to the invention.
  • heating conductors according to the invention made of an iron-based alloy are arranged on a hotplate, which are in particular subjected to power together with a voltage, it is advantageous to arrange them over a hotplate in a surface-distributed manner. This makes it easier to detect local overheating and take this overheating into account. Furthermore, in certain types of hotplates, it is possible to replace conventional heating conductors with heating conductors according to the invention made of an iron-based alloy in usually particularly hot areas. The different heaters or heating conductors can have approximately the same output.
  • the hotplate has a normal heating conductor, the resistance of which increases from approx. 15 ohms at room temperature to approx. 20 ohms at 800 ° C.
  • the hotplate has a PTC heating conductor, the resistance of which increases from 5 ohms at room temperature to approx. 32 ohms at 800 ° C.
  • the two heating conductors should be connected in series and operated with a voltage of 230 V.
  • the temperature curve should be illustrated using the following table:
  • a pot with good heat extraction is heated at 300 ° C with an output of almost 2kW. If the pan is empty and the temperature of the hotplate rises sharply, the output is significantly reduced and you only get about half of it at the highest temperatures of almost 800 ° C Heating output of just over 1kW. This enables cooling or less intense heating again.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Resistance Heating (AREA)

Abstract

L'invention concerne, suivant une forme d'exécution, un dispositif de chauffage électrique (11) comprenant une plaque chauffante à contact (12) sur laquelle sont agencés des filaments de chauffage du type fils métalliques (14). Au moins l'un des filaments de chauffage (14b) est constitué par un matériau ayant un effet PTC, par exemple, un alliage à base de fer. Celui-ci conserve, pendant toute la durée du fonctionnement de la plaque, une structure cristalline cubique centrée et présente en même temps l'effet PTC. Un tel filament de chauffage (14) offre, en plus de sa fonction de chauffage, un réglage de température indépendant, empêchant toute température excessive, ce qui permet de supprimer des limiteurs de température distincts, munis de contacts de commutation.
EP04716592A 2003-03-05 2004-03-03 Dispositif de chauffage electrique a plaque chauffante a contact Withdrawn EP1602262A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE2003110255 DE10310255A1 (de) 2003-03-05 2003-03-05 Elektrische Heizung mit einer Kontaktkochplatte
DE10310255 2003-03-05
PCT/EP2004/002125 WO2004080127A1 (fr) 2003-03-05 2004-03-03 Dispositif de chauffage electrique a plaque chauffante a contact

Publications (1)

Publication Number Publication Date
EP1602262A1 true EP1602262A1 (fr) 2005-12-07

Family

ID=32864312

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04716592A Withdrawn EP1602262A1 (fr) 2003-03-05 2004-03-03 Dispositif de chauffage electrique a plaque chauffante a contact

Country Status (5)

Country Link
EP (1) EP1602262A1 (fr)
CN (1) CN1757265A (fr)
DE (1) DE10310255A1 (fr)
WO (1) WO2004080127A1 (fr)
ZA (1) ZA200505471B (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006017998A1 (de) * 2006-04-07 2007-10-11 E.G.O. Elektro-Gerätebau GmbH Heizvorrichtung und Kochfeld mit einer solchen Heizvorrichtung
DE102007040891A1 (de) 2007-08-24 2009-04-30 E.G.O. Elektro-Gerätebau GmbH Heizeinrichtung, Verfahren zum Betrieb einer Heizeinrichtung und Elektrowärmegerät mit einer solchen Heizeinrichtung
CN102748218A (zh) * 2012-08-01 2012-10-24 华锐风电科技(集团)股份有限公司 风电机组的控制方法和装置
DE102014208408A1 (de) * 2014-05-06 2015-11-12 BSH Hausgeräte GmbH Heizkörper für ein Gargerät sowie Gargerät, insbesondere Kochfeld

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953711A (en) * 1973-11-06 1976-04-27 E.G.O. Elektro-Geraete Blanc Und Fischer Cooking units
DE2660073C2 (fr) * 1976-05-06 1987-04-30 Karl 7519 Oberderdingen De Fischer
DE2825475C3 (de) * 1977-10-14 1981-04-16 P. Ferrero & C. S.p.A., Alba, Cuneo Vorrichtung zum Erwärmen von in geschlossenen Behältern abgepackten zum unmittelbaren Verzehr bestimmten Nahrungsmitteln
DE3622415A1 (de) * 1986-07-03 1988-01-07 Ego Elektro Blanc & Fischer Strahlheizkoerper
DE4010479A1 (de) * 1990-03-31 1991-10-02 Bosch Gmbh Robert Gluehstiftkerze fuer brennkraftmaschinen
US5220155A (en) * 1992-03-12 1993-06-15 Emerson Electric Co. Heating and sensing apparatus for range top
JPH0579894U (ja) * 1992-03-28 1993-10-29 株式会社村田製作所 正特性サーミスタ発熱装置
AT408299B (de) * 1994-03-30 2001-10-25 Electrovac Heizvorrichtung für elektrische heizplatten, zündeinrichtungen, temperatursensoren od. dgl.
EP0853444B1 (fr) * 1997-01-10 2005-11-23 E.G.O. ELEKTRO-GERÄTEBAU GmbH Système à cuire avec une plaque de cuisson électrique, transférant la chaleur par conduction
DE19701640A1 (de) * 1997-01-10 1998-07-16 Ego Elektro Geraetebau Gmbh Kontaktwärmeübertragendes Kochsystem mit einer Elektro-Kochplatte
EP0967838B1 (fr) * 1998-06-25 2005-07-27 White Consolidated Industries, Inc. Assemblages chauffants à couche mince
DE10060273C1 (de) * 2000-12-05 2001-12-13 Vacuumschmelze Gmbh & Co Kg Glühstiftkerze für Brennkraftmaschinen

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004080127A1 *

Also Published As

Publication number Publication date
DE10310255A1 (de) 2004-09-16
WO2004080127A1 (fr) 2004-09-16
ZA200505471B (en) 2007-02-28
CN1757265A (zh) 2006-04-05

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