WO2002093981A1 - Appareil de chauffage electrique par rayonnement - Google Patents

Appareil de chauffage electrique par rayonnement Download PDF

Info

Publication number
WO2002093981A1
WO2002093981A1 PCT/GB2002/002187 GB0202187W WO02093981A1 WO 2002093981 A1 WO2002093981 A1 WO 2002093981A1 GB 0202187 W GB0202187 W GB 0202187W WO 02093981 A1 WO02093981 A1 WO 02093981A1
Authority
WO
WIPO (PCT)
Prior art keywords
electric heater
radiant electric
support
weight percent
insulation material
Prior art date
Application number
PCT/GB2002/002187
Other languages
English (en)
Inventor
Gavin John Coleman
Original Assignee
Ceramaspeed Limited
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 Limited filed Critical Ceramaspeed Limited
Priority to JP2002590717A priority Critical patent/JP2004525497A/ja
Publication of WO2002093981A1 publication Critical patent/WO2002093981A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
    • A47J27/00—Cooking-vessels
    • A47J27/004—Cooking-vessels with integral electrical heating means
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • 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 a radiant electric heater incorporating a dish-like support made from a non-metallic electrically insulating material.
  • the heater is particularly suited to environments which have high humidity or moisture levels.
  • microporous thermal insulation As an electrical and thermal insulation material in radiant electrical heaters such as ribbon or coil element heaters used in grills and cooking hobs.
  • radiant electrical heaters such as ribbon or coil element heaters used in grills and cooking hobs.
  • microporous thermal insulation provides many benefits including an ability to form raised profiles and excellent thermal and electrical insulation properties.
  • the construction of these heaters is typically a metal dish containing a compacted microporous insulation base into which a coil or ribbon element is retained.
  • the microporous thermal insulation typically comprises a dry particulate microporous material as defined hereinafter mixed with a high temperature ceramic or vitreous fibre reinforcement, titanium dioxide opacifier and, for high- temperature use, a small quantity of alumina powder to reduce high temperature shrinkage.
  • a dry particulate microporous material as defined hereinafter mixed with a high temperature ceramic or vitreous fibre reinforcement, titanium dioxide opacifier and, for high- temperature use, a small quantity of alumina powder to reduce high temperature shrinkage.
  • alumina powder to reduce high temperature shrinkage.
  • microporous' is used herein to identify porous or cellular materials in which the ultimate size of the cells or voids is less than the mean free path of an air molecule at NTP, i.e. of the order of 100 nm or smaller.
  • a material which is microporous in this sense will exhibit very low transfer of heat by air conduction (that is collisions between air molecules) .
  • microporous materials include aerogel, which is a gel in which the liquid phase has been replaced by a gaseous phase in such a way as to avoid the shrinkage which would occur if the gel were dried directly from a liquid.
  • aerogel which is a gel in which the liquid phase has been replaced by a gaseous phase in such a way as to avoid the shrinkage which would occur if the gel were dried directly from a liquid.
  • a substantially identical structure can be obtained by controlled precipitation from solution, the temperature and pH being controlled during precipitation to obtain an open lattice precipitate.
  • Other equivalent open lattice structures include pyrogenic (fumed) and electrothermal types in which a substantial proportion of the particles have an ultimate particle size less than 100 nm. Any of these materials, based for example on silica, alumina or other metal oxides, may be used to prepare a composition which is microporous as defined above.
  • the absorption of water or other liquids leads to a reduction in the size of the cells or voids of the microporous thermal insulation as it destroys the aforementioned porous structure.
  • the decrease in pore size results in increased solid - solid conduction within the body of the microporous insulation reducing the electrical and thermal insulation properties of the material and subsequently the benefits of the thermal insulation material to the application.
  • a radiant electric heater For some applications it is required that a radiant electric heater must be able to be energised successfully after it has been placed in a cavity with a container of water being boiled and producing steam continuously in excess of 500 hours.
  • Existing solutions to this problem include using a layer of high temperature glass to protect the microporous thermal insulation from moisture .
  • the glass has a thermal mass associated with it which adversely affects the performance of such heaters and is also expensive.
  • the use of a layer of glass also gives rise to other problems because a seal must be designed to ensure moisture does not penetrate around the glass and affect the microporous thermal insulation material.
  • a heating element within a powdered insulation material encapsulated in a glass, electrically insulating, cooking vessel.
  • the powdered insulation material acts as a dielectric and the powdered insulation material and heating element are contained within a closed chamber in the base of the cooking utensil.
  • Such a heating element is not well suited as a radiant heating element as heat transfer will primarily be by conduction and will consequently be relatively inefficient.
  • a radiant electric heater comprising: an electrically insulating dish-like support; a base layer of thermal insulation material provided within the support; at least one electric heating element supported relative to the base layer of thermal insulation material; wherein a peripheral wall of thermal insulating material is provided within the support and extends upwardly from the base around the periphery of the support to form a cavity within which the at least one electric heating element is located.
  • the base layer may be provided separate from the support.
  • the electrically insulating dish-like support may comprise materials selected from glass, ceramic, plastics compounds, woven or formed fibres, and minerals.
  • the plastics compounds of the electrically insulating dishlike support may have thermosetting or thermoplastic properties.
  • the woven or formed fibres of the electrically insulating dish-like support may be ceramic or glass fibres.
  • the thermal and electrical insulation material may comprise compacted microporous thermal and electrical insulation material.
  • the thermal insulation material may comprise 30 - 100 weight percent of finely divided metal oxide, 0 - 50 weight percent opacifier, 0 - 50 weight percent fibre material, and 0 - 15 weight percent inorganic binder as an intimate mixture.
  • the thermal insulation material may comprise substantially 58.5 weight percent of finely divided metal oxide, 30.0 weight percent opacifier, and 11.5 weight percent fibre material.
  • the at least one electric heating element may be exposed to the atmosphere.
  • Figure 1 is a plan view of an embodiment of a radiant electric heater incorporating a non-metallic dish-like support
  • FIG 2 is a cross-sectional view of the radiant electric heater of Figure 1 taken along the line A - A in Figure 1.
  • the radiant electric heater shown in the drawings comprises a dish-like support 1 in which there is a base layer 2 of electrical insulation material such as compacted microporous thermal and electrical insulation material.
  • the radiant electric heater is intended for incorporation into a grill or cooking hob appliance.
  • a wall 3 of thermal insulation material is provided around the entire periphery of the heater forming a cavity.
  • the wall 3 of thermal insulation material may be provided separate from the base layer 2, or may be integral with the base layer 2.
  • An electric heating element 5 is supported relative to the base layer 2 of thermal insulation material.
  • the heating element 5 may comprise any of the well-known forms of elements, such as wire, ribbon, or foil, or combinations thereof.
  • the heating element 5 is provided within the cavity formed by the peripheral wall 3 and is exposed to the atmosphere.
  • a terminal block 6 is arranged at the edge of the dish-like support 1 and electrically connected to the heating element 5, whereby the heating element 5 can be connected to a voltage supply for energising.
  • thermal cut-out device 4 is optionally provided, extending over the heating element 5, to switch off the heating element in the event of overheating.
  • the rod of the thermal cut-out device 4 passes through apertures in the peripheral wall 3 and is located in a space above the heating element 5 as shown in Figure 2.
  • the microporous thermal insulation material 2 provided in the radiant electric heater comprises 30 - 100 weight percent of finely divided metal oxide (such as silica) , 0 - 50 weight percent opacifier (such as titanium dioxide) , 0 - 50 weight percent fibre material, and 0 - 15 weight percent inorganic binder as an intimate mixture.
  • finely divided metal oxide such as silica
  • opacifier such as titanium dioxide
  • the microporous thermal insulation material 2 provided in the radiant electric heater may comprise substantially 58.5 weight percent of finely divided metal oxide, 30.0 weight percent opacifier, and 11.5 weight percent fibre material.
  • the dish-like support 1 comprises a material which is electrically insulating and which functions as an electrical barrier between the humidity- or moisture- impaired microporous thermal insulation and a grill or cooking hob appliance construction which is earthed electrically.
  • Suitable non-metallic dish materials include glass, ceramic, plastics compounds (both thermoset and thermoplastic) , woven or formed glass fibres or ceramic fibres, and minerals.
  • the dish-like support 1 may be moulded, cast or otherwise formed to pre-determined dimensions and tolerences.
  • the ability to form the dish-like support from specific materials depends on the physical properties of the materials and the limitations of the respective processes. These are well known to the skilled person and require no invention.
  • a radiant electric heater incorporating a non-metallic dish-like support is able to withstand testing in high humidity atmospheres. That is, despite the affinity of the microporous thermal insulation material to water being such that the porous structure of the microporous insulation material is reduced to a level which allows greater electrical and thermal conduction, a radiant electric heater incorporating a non- metallic dish-like support can be energised successfully after the radiant electric heater has been placed in a cavity with a container of water being boiled and producing steam continuously for a period in excess of 500 hours.

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Resistance Heating (AREA)
  • Surface Heating Bodies (AREA)

Abstract

L'invention concerne un appareil de chauffage électrique par rayonnement comprenant un support similaire à un disque d'isolation électrique (1), une couche de base (2) de matière d'isolation thermique située à l'intérieur du support (1), et au moins un élément de chauffage électrique (5) porté par la couche de base (2) de ladite matière. Une paroi périphérique (3) de la matière d'isolation thermique se situe à l'intérieur du support (1) et s'étend vers le haut, à partir de la base, autour de la périphérie du support (1) pour constituer une cavité, au sein de laquelle se trouve au moins élément électrique chauffant (5).
PCT/GB2002/002187 2001-05-15 2002-05-13 Appareil de chauffage electrique par rayonnement WO2002093981A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002590717A JP2004525497A (ja) 2001-05-15 2002-05-13 放射電熱器

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0111900.7 2001-05-15
GB0111900A GB0111900D0 (en) 2001-05-15 2001-05-15 Radiant electric heater

Publications (1)

Publication Number Publication Date
WO2002093981A1 true WO2002093981A1 (fr) 2002-11-21

Family

ID=9914705

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2002/002187 WO2002093981A1 (fr) 2001-05-15 2002-05-13 Appareil de chauffage electrique par rayonnement

Country Status (4)

Country Link
JP (1) JP2004525497A (fr)
CN (1) CN1518847A (fr)
GB (1) GB0111900D0 (fr)
WO (1) WO2002093981A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3289932A1 (fr) * 2016-06-28 2018-03-07 Maurer, Sabrina Élément de chauffage à résistance pouvant être inséré

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3612826A (en) * 1970-07-17 1971-10-12 Gen Motors Corp Surface temperature indicator light for ceramic top infrared radiant range
GB2275404A (en) * 1993-02-11 1994-08-24 Ceramaspeed Ltd Supporting radiant electrical heating element
WO2001009057A1 (fr) * 1999-07-31 2001-02-08 Microtherm International Limited Procede de fabrication de corps d'isolation thermique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3612826A (en) * 1970-07-17 1971-10-12 Gen Motors Corp Surface temperature indicator light for ceramic top infrared radiant range
GB2275404A (en) * 1993-02-11 1994-08-24 Ceramaspeed Ltd Supporting radiant electrical heating element
WO2001009057A1 (fr) * 1999-07-31 2001-02-08 Microtherm International Limited Procede de fabrication de corps d'isolation thermique

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3289932A1 (fr) * 2016-06-28 2018-03-07 Maurer, Sabrina Élément de chauffage à résistance pouvant être inséré

Also Published As

Publication number Publication date
GB0111900D0 (en) 2001-07-04
CN1518847A (zh) 2004-08-04
JP2004525497A (ja) 2004-08-19

Similar Documents

Publication Publication Date Title
CA1108386A (fr) Materiau d'isolation thermique
EP0560479B1 (fr) Matériau d'isolation thermique microporeux
CA1077118A (fr) Surface de chauffe en verre, et element chauffant sous gaine
US4221672A (en) Thermal insulation containing silica aerogel and alumina
US5453597A (en) Electrical heating element and heater incorporating same
US20160010873A1 (en) High performance surface unit for heating
US5220155A (en) Heating and sensing apparatus for range top
US5477605A (en) Method of manufacturing a radiant electric heater
US5512731A (en) Radiant electric heater
EP0625866B1 (fr) Corps de chauffe rayonnant
WO2002093981A1 (fr) Appareil de chauffage electrique par rayonnement
WO2002102115A1 (fr) Systeme de chauffage electrique par rayonnement
US5471737A (en) Method of manufacturing a radiant electric heater
US20020113058A1 (en) Base for an electric heater and method of manufacture
US6013902A (en) Radiant electric heater
JP2003007434A (ja) 輻射電気ヒーター
GB2389504A (en) Electrical food warming apparatus
GB2318489A (en) Disk-like support for radiant electric heater
CN2163969Y (zh) 电热储能取暖器
GB2285058A (en) Alloy for radiant electric heater
EP1375446A1 (fr) Materiau d'isolation thermique
GB2333680A (en) Electric toaster elements
KR200162404Y1 (ko) 전기온풍기용 발열체
JP2561742B2 (ja) 発熱装置
JPH02239585A (ja) 電熱ユニット

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 028097696

Country of ref document: CN

WWE Wipo information: entry into national phase

Ref document number: 2002590717

Country of ref document: JP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase