EP1109478A2 - Fond pour recipient chauffant et mode de fabrication - Google Patents

Fond pour recipient chauffant et mode de fabrication

Info

Publication number
EP1109478A2
EP1109478A2 EP99943077A EP99943077A EP1109478A2 EP 1109478 A2 EP1109478 A2 EP 1109478A2 EP 99943077 A EP99943077 A EP 99943077A EP 99943077 A EP99943077 A EP 99943077A EP 1109478 A2 EP1109478 A2 EP 1109478A2
Authority
EP
European Patent Office
Prior art keywords
base
channel
heating element
base plate
electrical
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Withdrawn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
EP99943077A
Other languages
German (de)
English (en)
Inventor
Barry Goodwin
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.)
Aptech (uk) Ltd
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP1109478A2 publication Critical patent/EP1109478A2/fr
Withdrawn legal-status Critical Current

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

Definitions

  • This invention relates to a base adapted for use in a heating vessel, more particularly a base which has an electrical heating element as an integral part thereof, and a method of manufacture thereof.
  • Conventional heating vessels such as kettles, comprise a container for receiving a liquid to be heated, above or below a base of which there is a heating element for heating the liquid.
  • the heating element is a separately made and fitted component from the base.
  • a base adapted to be included in a container of a heating vessel, the base comprising a base plate having a channel therein and an electrical heating element located and held in the channel such that the heating element and the base plate form one integral unit.
  • a heating vessel having a base according to the first aspect of the invention.
  • the heating vessel may, for example, be a kettle or a coffee maker but it may be provided for other purposes.
  • the heating element may be a resistance heating element, heat being produced by resistance to the passage of electrical current through the element.
  • the heating element may comprise a resistance wire. This may be made of metal alloy, such as a nickel chrome alloy.
  • the resistance wire may be helically coiled in the manner of a helical spring.
  • An electrical connector may be provided at each end of the resistance wire.
  • Each electrical connector may be a cold tail, may be made of nickel, and may be provided with an insulating sleeve, which may be made of fibre glass.
  • the channel provided in the base plate may extend annularly and may have a U-shaped cross-section. It may extend in other configurations and be of other cross-sections, as desired.
  • the heating element should be situated in the channel such that it does not come into electrical contact with walls of the channel.
  • An electrical insulating, thermally conducting material may be provided around the heating element in the channel. Preferably the material acts to hold the heating element in a substantially central position in the channel, out of contact with the walls of the channel.
  • the material may be a powder, and may be magnesium oxide powder.
  • a closure member is preferably placed over the channel and may be pressed into, and secured, as by welding, in the channel. Electrical insulating, thermally conducting material provided in the channel, is preferably compressed by location of the closure member in the channel, thereby to increase the thermal conductivity of the material.
  • the closure member may be provided with one or more apertures for the passage therethrough of an electrical connector or connectors.
  • a seal, for example of silicon, may be provided in the or each aperture.
  • the base plate and closure member may be made of stainless steel.
  • the heating vessel may be constructed from a low melting point material such as polypropylene.
  • the transfer of heat from the base to a liquid in the heating vessel is very efficient. However, this is desirable until a 'no liquid' condition occurs within the vessel - at this point the element may be in danger of overheating. It is desirable to be able to detect a rise in temperature of the element, and to cut-off the electrical supply thereto preventing overheating of the element.
  • the base may be provided with one or more electrical cut-off devices. Preferably at least two cut-off devices are provided, this reduces the possibility of failure to disconnect the electrical supply to the element.
  • the or each or some of the cut-off devices may comprise a bimetal device.
  • the or each or some of the cut-off devices may comprise a solid state device.
  • each cut-off device senses the element temperature, and when this rises above a chosen threshold level the cut-off device disconnects the electrical supply to the element.
  • the or each or some of the cut-off devices may be fitted to the underside of the base.
  • the or each or some of the cut-off devices may be provided with a heat conducting strip, which may conduct heat from the element or around the element to a part of the device remote from the element.
  • the or each or some of the cut-off devices may be connected to a heat conducting strip, which may conduct heat from the element or around the element to the device.
  • At least a part of the or each or some of the conducting strips may be positioned, e.g. by pressing, within the channel of the base.
  • the or each or some of the conducting strips may be manufactured from copper.
  • a method of manufacture of a base comprising the steps of: forming a channel in a base plate; inserting and positioning a heating element in the channel and securing the heating element in the channel, such that the heating element and the base plate form an integral unit.
  • the channel may be formed in the base plate by a pressing operation.
  • the heating element is positioned and secured in the channel out of electrical contact with walls of the channel.
  • the method may comprise the further steps of surrounding the heating element with an electrical insulating, thermally conducting material in the channel, and locating a closure member in the channel, e.g. by pressing the closure member into the channel, and fixing the closure member to the base plate, to close the channel with the heating element enclosed therein.
  • the closure member may be welded to the base plate.
  • the heating element may be inserted into and be accurately positioned in the channel progressively along the channel.
  • thermally conducting material may be immediately introduced into the channel to surround the element, so that the element becomes embedded in the material and is held firmly in position in the channel by the material.
  • the insertion and positioning of the element in the channel and the introduction of the material into the channel may be automatically performed and controlled.
  • an apparatus for positioning a heating element in a channel of a base comprising: means for holding a base plate of the base; means for rotating the base plate about a central axis thereof; and positioning means for progressively bringing the heating element into the desired position in the channel as the base plate is rotated.
  • the positioning means may comprise first and second positioning means.
  • the first positioning means may comprise a support arm which may terminate in a hooked portion.
  • the hooked portion preferably extends beneath and around the heating element, thereby supporting the heating element from below to progressively bring it into the desired position in the channel as the base plate is rotated.
  • the second positioning means may comprise a roller.
  • the roller preferably abuts an upper surface of the heating element, thereby acting in co-operation with the hooked portion to progressively bring the heating element into the desired position in the channel as the base plate is rotated.
  • the apparatus may also comprise a feed pipe for introducing the material into the channel as the base plate is rotated.
  • Figure 1 is a cross-sectional view of a portion of a first embodiment of a base according to the first aspect of the present invention
  • Figure 2 is a top plan view of the base of Figure 1 ;
  • Figure 3 illustrates a first stage of manufacture of a base
  • Figure 4 is a top plan view of Figure 3;
  • Figure 5 illustrates a second stage of manufacture of the base of Figure 3 and Figure 4;
  • Figure 6 is a top plan view of Figure 5;
  • Figure 7 illustrates a third stage of manufacture of the base of Figures 3 to 6;
  • Figure 8 is a cross-sectional view of a portion of a second embodiment of a base according to the first aspect of the present invention.
  • Figure 9 is a bottom plan view of the base of Figure 8.
  • Figures 1 and 2 show a base 1 for a heating vessel, for example a kettle.
  • the base comprises a circular base plate 2 formed with a concentric annular channel 3 of U-shaped cross-section.
  • the base further comprises a heating element 4 situated within the channel.
  • the heating element is in the form of a helically coiled, spring-like, wire of nickel-chrome alloy. This is laid in the channel to form a ring.
  • Each end of the heating element is connected to a respective nickel cold tail 5.
  • a first portion 6 of each cold tail 5 lies within and along the channel, and is spot- welded to the associated end of the heating element.
  • each cold tail Integrally joined to the first portion 6 of each cold tail is a second portion 8 which extends substantially perpendicular to the first portion, and projects upwards out of the channel.
  • the second portion is joined to a third portion 9 ( Figure 2) which is substantially perpendicular to the second portion, and projects in a generally radially inwardly direction with respect to the annular channel.
  • Radially inner ends of the third portions 9 of the two cold tails 5 are received in and secured in a mounting block 10.
  • An insulating sleeve 11 made of fibre glass is fitted to each cold tail, to surround part of the first portion, all of the second portion, and part of the third portion of the cold tail, as shown.
  • the channel 3 is filled with magnesium oxide powder 12 which surrounds the heating element 4 and holds this firmly embedded in the powder in a substantially central position along the length of the channel.
  • the magnesium oxide powder electrically insulates the heating element from the walls of the channel, but is thermally conductive allowing heat from the element to pass through it to the base plate.
  • a closure ring 13 is located in the mouth of the channel.
  • the closure ring 13 is of substantially U-shaped cross-section ( Figure 7) , and the arms of the U-shape form a frictional fit with the side walls of the channel, sealing the magnesium oxide powder within the channel.
  • the closure ring 13 is spot- welded to the base plate 2 to retain it securely in the channel.
  • Cut-outs 14 are provided in the closure ring for the two cold tails 5.
  • the second portions 8 of the cold tails pass out of the channel through the cut-outs, as shown.
  • a silicon sealant 15 is provided in each cut-out 14, surrounding the respective cold tail portion.
  • FIGS 3 to 7 show various stages in the manufacture of the base.
  • the base plate 2 has been pre-formed, by pressing, with the channel 3, and the mounting block 10 has been fixed to the base plate.
  • the next stage of manufacture ( Figure 5 and Figure 6) entails filling the channel 3 with magnesium oxide powder whilst positioning the heating element accurately within the channel.
  • the apparatus comprising a positioning and filling device which supports the base plate and is provided with a support arm 20, a control roller 21 and a feed pipe 22.
  • the support arm 20 of the device is positioned in the channel, initially adjacent one end of the heating element ( Figure 5) , such that a hooked bottom end 20' of the support arm is positioned in the bottom of the channel ( Figure 4) and extends underneath and around the heating element.
  • the device then rotates the base plate about its central axis whilst the support arm 20 and feed pipe 22 are held stationary.
  • the hooked bottom end 20 ' of the support arm 20 supports the heating element as the base plate is rotated and positions the element at the correct distance from the bottom of the channel and away for the side walls of the channel.
  • the control roller 21 is lowered onto the top of the heating element and prevents it from moving upwards out of position as the base plate is rotated.
  • magnesium oxide powder 12 is delivered through the feed pipe 22 behind the control roller and support arm. The magnesium oxide powder is filled to approximately the top of the channel. A full revolution of the base plate takes place and so the heating element is progressively positioned in the channel along the length of the channel and embedded in the magnesium oxide powder.
  • the control roller is lifted clear of the heating element as the second cold tail reaches the support arm.
  • the flow of magnesium oxide powder from the feed pipe 22 is interrupted and the support arm and feed pipe are lifted clear of the channel allowing the base plate to be removed from the positioning and filling device.
  • the closure ring 13 is placed into the mouth of the channel, such that the cold tails 8 pass through the cut outs 14 of the closure ring.
  • a punch unit 23 is used to force the closure ring down into the channel thus compressing the magnesium oxide powder. Typically a load of 30 tons is exerted on the closure ring. This compresses and increases the thermal conductivity of the powder.
  • the closure ring is secured in the channel by spot welding the arms of its U-shaped cross-section to the base plate at the sides of the channel. Silicon sealant is applied in each cut-out to prevent the ingress of moisture into the channel. The base is then complete and ready for use in a heating vessel.
  • the base plate can be welded in place to form the bottom of the hollow body of a kettle or other heating vessel, a rim portion of the plate being welded to the bottom periphery of a circumferential wall of the body.
  • the heating element With the base plate, becomes an integral part of the body of the vessel.
  • FIGS 8 and 9 show a second embodiment of a base for a heating vessel. This is similar to the base of Figures 1 and 2, and like features have been given the same reference numerals.
  • the base 1 in this embodiment is provided with an electrical cut-off device 30, comprising a solid state device. This is connected to a copper heat conducting strip 31, part of which is positioned within the channel 3 of the base as shown, 180 degrees from the electrical connections i.e. the cold tails 5.
  • the conducting strip conducts heat from the heating element 4 or around the element to the device, which senses the element temperature and when this rises above a chosen threshold level the device disconnects the electrical supply to the element.
  • the thickness of the base plate of each base may be of comparable thickness to the wall thickness of the body, so that it may be relatively thin.
  • the base described may be manufactured cheaply and with a high degree of accuracy in the positioning and insulation of the heating element in the channel, so that failure such as is often experienced with conventional heating elements through incorrect location of the wire in the insulating material and sheath, is avoided.

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Cookers (AREA)
  • Resistance Heating (AREA)

Abstract

Ce fond (1) est constitué d'une platine de fond (2) dans laquelle est ménagé un canal (3). Un élément électrique chauffant (4) est disposé et maintenu dans le canal de façon que l'élément chauffant (4) et la platine (2) forment un ensemble monobloc. Le fond (1) est conçu pour être intégré à l'enceinte d'un récipient chauffant tel qu'une bouilloire. L'élément chauffant (4) peut être un fil de résistance. On peut garnir l'intérieur du canal (3) d'un matériau électro-isolant et thermo-conducteur (12) enrobant l'élément chauffant (4) de façon à le retenir bien centré dans le canal (3). On le recouvre de préférence d'un couvercle (13) fixé à l'intérieur du canal (3). Le fond (1) peut être pourvu d'au moins un dispositif coupe circuit (30) venant interrompre l'alimentation électrique de l'élément (4) en cas de surchauffe. L'invention concerne également, d'une part un procédé de fabrication de ce fond (1), et d'autre part un appareil permettant de centrer l'élément chauffant (3) dans le canal (3) du fond (1).
EP99943077A 1998-09-03 1999-08-31 Fond pour recipient chauffant et mode de fabrication Withdrawn EP1109478A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9819091 1998-09-03
GBGB9819091.1A GB9819091D0 (en) 1998-09-03 1998-09-03 Base for a heating vessel and a method of manufacturing thereof
PCT/GB1999/002866 WO2000013561A2 (fr) 1998-09-03 1999-08-31 Fond pour recipient chauffant et mode de fabrication

Publications (1)

Publication Number Publication Date
EP1109478A2 true EP1109478A2 (fr) 2001-06-27

Family

ID=10838202

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99943077A Withdrawn EP1109478A2 (fr) 1998-09-03 1999-08-31 Fond pour recipient chauffant et mode de fabrication

Country Status (4)

Country Link
EP (1) EP1109478A2 (fr)
AU (1) AU5636299A (fr)
GB (2) GB9819091D0 (fr)
WO (1) WO2000013561A2 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2379851B (en) * 2001-09-11 2005-09-28 Otter Controls Ltd Underfloor heating elements and element protector control assemblies for underfloor heating elements
RU2415634C2 (ru) 2004-10-21 2011-04-10 Стрикс Лимитед Электронагреватель (варианты) сосуда для нагрева жидкости и сосуд для нагрева жидкости
CN200941691Y (zh) * 2006-07-28 2007-08-29 游明丰 发热器
CN103334539B (zh) * 2013-07-17 2015-08-05 王睿敏 复合墙板、复合墙板与横梁挂接单元和复合墙板与横梁连接结构

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB255710A (en) * 1925-12-04 1926-07-29 Cutler Hammer Mfg Co Improvements in or relating to electric heating devices
GB482544A (en) * 1936-02-27 1938-03-31 Siemens Schuckeriwerke Ag Improvements in or relating to electric boiling vessels
GB719962A (en) * 1952-05-19 1954-12-08 Simplex Electric Co Ltd Improvements in vessels for heating liquids
CH380832A (de) * 1959-09-29 1964-08-15 Forbach Gmbh & Co Kg Verfahren zum Haltern der Isoliermassebettung einer elektrischen Heizwendel in einem Plattenheizkörper für Heisswassergeräte und dergleichen
US4052590A (en) * 1976-10-28 1977-10-04 National Presto Industries, Inc. Electric appliance with intermittently staked sheathed heating element
CH658356A5 (de) * 1982-12-08 1986-10-31 Jura Elektroapparate Fab Heizvorrichtung und verfahren zur herstellung derselben.
FR2551940B2 (fr) * 1983-03-31 1989-07-07 Cuisi Technic Sarl Corps chauffant electrique, et foyer de cuisson equipe de ce corps chauffant
US5140134A (en) * 1990-08-10 1992-08-18 Allied Precision Industries, Inc. Nestable stackable heated bowl with thermostatically controlled electric heating element
CA2099189A1 (fr) * 1993-06-25 1994-12-26 Lunchiang Hu Poelon a commande par thermostat avec capteur situe au fond dudit poelon
US5380986A (en) * 1994-01-13 1995-01-10 Mullen; Charles F. Multi-purpose electric fast cooking apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0013561A2 *

Also Published As

Publication number Publication date
WO2000013561A3 (fr) 2000-07-27
GB9819091D0 (en) 1998-10-28
AU5636299A (en) 2000-03-27
WO2000013561A2 (fr) 2000-03-16
GB9920315D0 (en) 1999-11-03
GB2342551A (en) 2000-04-12
GB2342551B (en) 2003-06-11

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