EP0637194B1 - Elektrischer Wärmestrahler - Google Patents

Elektrischer Wärmestrahler Download PDF

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Publication number
EP0637194B1
EP0637194B1 EP94305133A EP94305133A EP0637194B1 EP 0637194 B1 EP0637194 B1 EP 0637194B1 EP 94305133 A EP94305133 A EP 94305133A EP 94305133 A EP94305133 A EP 94305133A EP 0637194 B1 EP0637194 B1 EP 0637194B1
Authority
EP
European Patent Office
Prior art keywords
heater
heater according
base layer
strip
heating element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94305133A
Other languages
English (en)
French (fr)
Other versions
EP0637194A1 (de
Inventor
Kevin Ronald Mcwilliams
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.)
Ceramaspeed Ltd
Original Assignee
Ceramaspeed Ltd
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 Ceramaspeed Ltd filed Critical Ceramaspeed Ltd
Publication of EP0637194A1 publication Critical patent/EP0637194A1/de
Application granted granted Critical
Publication of EP0637194B1 publication Critical patent/EP0637194B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H05B3/68—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

  • This invention relates to radiant electric heaters, particularly for use with glass ceramic top cookers.
  • Radiant electric heaters are well known which comprise a metal dish, for example of circular, rectangular or oval shape, containing a base layer of thermal and electrical insulating material supporting one or more electrical heating elements.
  • a peripheral wall of insulating material is also generally provided in the dish.
  • heating element has comprised coiled bare resistance wire, the wire generally having a circular cross-section and being formed into a helical coil.
  • wire which may for example comprise an iron-chromium-aluminium alloy
  • wire coil elements are readily adaptable to heaters of different sizes and to requirements for different operating voltages by appropriate variation of the above parameters.
  • a strip or ribbon of corrugated form (sometimes referred to as crinkled, or sinuous, or serpentine, or convoluted form) is generally adopted in order to accommodate the required length of ribbon within the heated zone.
  • other configurations of strip or ribbon such as a helical coil, may be adopted if desired.
  • a number of parameters of the strip or ribbon can be varied in order to achieve the required heater performance. These parameters comprise: thickness of the strip or ribbon; width of the strip or ribbon; total length of the strip or ribbon; and corrugation (or coil) pitch and corrugation depth of the strip or ribbon.
  • the strip or ribbon element When an operating voltage is applied, the strip or ribbon element heats up to full radiance much faster than a corresponding coiled wire element. In a typical arrangement the strip or ribbon element is found to heat up in about one third of the time required by a corresponding coiled wire element.
  • strip or ribbon elements are less versatile than coiled wire elements in meeting the requirements for heaters of different sizes and operating voltages.
  • a much longer strip or ribbon element is required than for a corresponding coiled wire element.
  • a strip or ribbon element may be required to be more than twice as long as an equivalent coiled wire element. This is because of practical limitations imposed on the minimum value of the corrugation pitch and the maximum value of the corrugation depth.
  • the length of the strip or ribbon must be correspondingly increased to increase the electrical resistance of the element in order to achieve the specified power.
  • a radiant electric heater comprising a support dish containing a base layer of thermal and electrical insulating material and at least one electrical heating element supported by the insulating material, wherein the heating element comprises first and second portions electrically connected in series for operation, the first portion comprising an elongate strip of resistive material and the second portion comprising coiled bare resistance wire.
  • the first portion of the heating element preferably extends across a major part of the area of the base layer of the radiant heater and the second portion preferably extends across a minor part of the area of the base layer of the radiant heater.
  • the series connection between the first and second portions may be effected directly between ends thereof or by way of a connector mounted on the dish.
  • a connector mounted on the dish.
  • Such a connector may also be used for connecting the element to a voltage source.
  • the heating element may comprise a metal or metal alloy, for example nickel-chromium alloy or iron-chromium-aluminium alloy.
  • the first portion and the second portion may conveniently comprise the same resistive material.
  • the elongate strip of the first portion is preferably supported on edge by the base layer.
  • the elongate strip of the first portion may be mounted in or on the base layer, for example by partially embedding the first portion in the base layer.
  • the elongate strip of the first portion is preferably corrugated in form.
  • the electrical heating element may be provided singly in a heater, or one or more such elements may be provided in a heater having multiple heated zones.
  • the multiple heated zones may be separated by a dividing wall if desired.
  • the advantageous use of a strip or ribbon heating element may be maximised while making use of a proportion of coiled wire element to enable the available heater area and/or supply voltage requirement to be accommodated.
  • a radiant electric heater for use under a glass ceramic top of a cooker is constructed comprising a metal dish 1 of well known form containing a base layer 2 of thermal and electrical insulating material.
  • insulating material suitably comprises microporous thermal and electrical insulating material which is well known to the skilled person.
  • a peripheral wall 3 of insulating material is provided, the top surface of which contacts the underside of the glass ceramic top of the cooker (not shown) when the heater is installed for operation.
  • a heating element is provided, supported on the base 2 and comprising a first portion 4 and a second portion 5.
  • the first portion 4 extends across a major part of the area of the base layer 2, while the second portion 5 extends across a minor part of the area of the base layer 2.
  • the first portion 4 of the heating element comprises an elongate strip or ribbon of a resistive material, for example metal or metal alloy such as an iron-chromium-aluminium alloy.
  • the strip or ribbon portion 4 is provided of corrugated form, as indicated in detail by reference numeral 6, and is supported on edge.
  • the elongate strip is generally rectangular in cross section, is of corrugated form and has a thickness t, a width w, a corrugation pitch x and a corrugation depth y.
  • Figure 4 exemplifies a shaped elongate strip or ribbon of the type used in portion 4 of Figure 3, although the actual pattern shown in Figure 4 is somewhat different from that of portion 4 in Figure 3. It would be preferred to provide the entire heating element of Figure 3 in the strip or ribbon form of portion 4, but as explained hereinbefore this is not possible with heaters of small heated areas or zones and/or where a heater is required to be operated at a high voltage, for example 400 volts rather than, say, 230 volts.
  • a strip or ribbon element is required to be considerably longer than an element comprising a well known form of coiled bare resistance wire. Consequently there can be insufficient space within the heater to accommodate an element entirely of strip or ribbon form.
  • the elongate strip or ribbon is supported on edge by the base layer 2. This is generally accomplished by partially embedding the strip or ribbon in the base layer.
  • portion 5 which comprises coiled bare resistance wire of known form.
  • the coiled bare resistance wire is shown in more detail in Figure 1, the wire having a diameter d, the coil having a diameter c, and adjacent turns of the coil having a pitch p.
  • Such coiled wire is suitably composed of a resistive material such as metal or metal alloy similar to the strip or ribbon of portion 4, for example iron-chromium-aluminium alloy.
  • the portions 4 and 5 are electrically connected in series, suitably at a connector 7 which is also used for connecting the heater to a voltage supply.
  • the portion 5 of coiled resistance wire may suitably form a complete turn around the periphery of the strip or ribbon portion 4 of the element.
  • one or more further turns of coiled resistance wire may be required for portion 5 surrounding the portion 4.
  • the proportion of coiled wire should be kept as small as possible.
  • the resulting heater may be provided with a well-known form of thermal limiter (not shown) extending across it and serving to prevent overheating when the heater is installed and operating in a cooking appliance with a glass ceramic top.
  • portions 4 and 5 can be envisaged. These could include the strip or ribbon portion 4 surrounding the coiled wire portion 5, or portions 4 and 5 interspersed with one another, whilst retaining the series connection between the portions.
  • the elongate strip or ribbon may take other forms than a corrugated strip, such as a helical coil.

Landscapes

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

Claims (11)

  1. Elektrische Strahlungsheizung, umfassend eine Aufnahmeschüssel (1), die eine Basisschicht (2) aus thermischem und elektrischem Isoliermaterial und wenigstens ein von dem Isoliermaterial getragenes elektrisches Heizelement enthält, dadurch gekennzeichnet, daß das Heizelement einen ersten und einen zweiten Abschnitt aufweist, die für den Betrieb elektrisch in Reihe geschaltet sind, wobei der erste Abschnitt (4) einen länglichen Streifen aus Widerstandsmaterial und der zweite Abschnitt (5) einen gespulten blanken Widerstandsdraht umfaßt.
  2. Heizung nach Anspruch 1, dadurch gekennzeichnet, daß der erste Abschnitt (4) des Heizelementes über einen größeren Teil der Fläche der Basisschicht (2) der Strahlungsheizung und der zweite Abschnitt (5) über einen kleineren Teil der Fläche der Basisschicht (2) der Strahlungsheizung verläuft.
  3. Heizung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Reihenschaltung zwischen dem ersten Abschnitt (4) und dem zweiten Abschnitt (5) unmittelbar zwischen deren Enden erfolgt.
  4. Heizung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Reihenschaltung zwischen dem ersten Abschnitt (4) und dem zweiten Abschnitt (5) mit Hilfe eines auf der Aufnahmeschüssel (1) montierten Steckverbinders (7) erfolgt.
  5. Heizung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß das Heizelement ein Metall oder eine Metallegierung umfaßt.
  6. Heizung nach Anspruch 5, dadurch gekennzeichnet, daß die Metallegierung Nickel-Chrom oder Eisen-Chrom-Aluminium umfaßt.
  7. Heizung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß der erste Abschnitt (4) und der zweite Abschnitt (5) dieselbe Widerstandsmaterialzusammensetzung haben.
  8. Heizung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß der längliche Streifen des ersten Abschnittes (4) auf dem Rand in der Basisschicht (2) steht.
  9. Heizung nach Anspruch 8, dadurch gekennzeichnet, daß der längliche Streifen des ersten Abschnittes (4) auf oder in der Basisschicht (2) montiert ist.
  10. Heizung nach Anspruch 9, dadurch gekennzeichnet, daß der längliche Streifen des ersten Abschnittes (4) teilweise in der Basisschicht (2) eingebettet ist.
  11. Heizung nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß der längliche Streifen des ersten Abschnittes (4) eine gewellte Form hat.
EP94305133A 1993-07-28 1994-07-13 Elektrischer Wärmestrahler Expired - Lifetime EP0637194B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9315589 1993-07-28
GB9315589A GB2280578B (en) 1993-07-28 1993-07-28 Radiant electric heater

Publications (2)

Publication Number Publication Date
EP0637194A1 EP0637194A1 (de) 1995-02-01
EP0637194B1 true EP0637194B1 (de) 1997-09-24

Family

ID=10739551

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94305133A Expired - Lifetime EP0637194B1 (de) 1993-07-28 1994-07-13 Elektrischer Wärmestrahler

Country Status (7)

Country Link
EP (1) EP0637194B1 (de)
AT (1) ATE158684T1 (de)
DE (1) DE69405834T2 (de)
DK (1) DK0637194T3 (de)
ES (1) ES2107138T3 (de)
GB (1) GB2280578B (de)
GR (1) GR3025466T3 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2003246042B2 (en) * 1999-02-19 2005-07-07 Wik Far East Ltd Electric Heating Plate
GB0221519D0 (en) * 2002-09-17 2002-10-23 Ceramaspeed Ltd Radiant electric heater
JP2005197074A (ja) * 2004-01-07 2005-07-21 Ngk Insulators Ltd 抵抗発熱体およびヒーター
CN109041291A (zh) * 2018-07-02 2018-12-18 安徽思源三轻智能制造有限公司 一种加热均匀的加热板

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8514785D0 (en) * 1985-06-11 1985-07-10 Micropore International Ltd Infra-red heaters
DE3812490A1 (de) * 1988-04-15 1989-11-02 Ego Elektro Blanc & Fischer Strahlheizkoerper
GB8926289D0 (en) * 1989-11-21 1990-01-10 Ceramaspeed Ltd Radiant electric heaters
DE4023810A1 (de) * 1990-07-27 1992-01-30 Ako Werke Gmbh & Co Heizkoerper fuer ein elektrisches kochfeld
DE4031343C2 (de) * 1990-10-04 1996-04-11 Ako Werke Gmbh & Co Verfahren zum Befestigen eines Heizdrahtes an einem Isolierträger und Heizkörper, insbesondere für eine Glaskeramik-Kochplatte

Also Published As

Publication number Publication date
DK0637194T3 (da) 1998-03-30
DE69405834T2 (de) 1998-03-12
ES2107138T3 (es) 1997-11-16
GR3025466T3 (en) 1998-02-27
GB2280578B (en) 1997-02-26
GB9315589D0 (en) 1993-09-08
GB2280578A (en) 1995-02-01
DE69405834D1 (de) 1997-10-30
ATE158684T1 (de) 1997-10-15
EP0637194A1 (de) 1995-02-01

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