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
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/02—Induction heating
  • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
  • H05B6/12—Cooking devices
  • H05B6/1209—Cooking devices induction cooking plates or the like and devices to be used in combination with them

Definitions

• the present invention relates to a cooking appliance with induction, and more specifically relates to the hob fitted to such a apparatus.
• the hot plates known from said document DE-U-8 914 894 are brought to a relatively high temperature, their edge must be relatively distant (at least 40 mm) from the support surrounding, if the latter is made of plastic.
• a large cooking container is placed on the hot plate, it communicates by conduction of heat to the support surrounding the plate, which requires either to increase the dimensions of the hot plate (therefore to increase the cost price), or to renounce when using plastic for the support.
• the preceding advantage is not exploited in the heating by induction fireplace. Indeed, the heating occurring directly at the level of the container placed above the inductor, the rise in temperature of the hob, due to conduction thermal from the container to the plane, does not exceed, in the worst case, 300 to 350 ° C depending on the temperature regulation used.
• glass ceramic is an expensive material, which strikes almost unnecessarily, given the previous remark, the price of household appliances.
• the main purpose of the present invention is to find a replacement solution that significantly reduces the costs of a induction cooking appliance.
• the present invention relates to an apparatus for induction cooking with a substantially flat hob and at least one inducing focal point placed under said plate, characterized in that that said plate is constituted by the assembly of a first part obtained by molding a heat-resistant material, and comprising a hole of size greater than the diameter of the inducing hearth, and of a second part glass, intended to support a container to be heated, said second part completely closing the hole in the first part.
• Figure 1 there is shown schematically, in view partial elevation, a container 1 to be heated placed on the plate 2 of a induction cooking appliance with an induction cooker 3.
• the inducing focus 3 is conventionally composed of one or more several coils placed concentrically.
• the coils are shaped generally circular and the diameter of the inducing focus should preferably correspond to the diameter of the largest container to be heated, the latter being placed on the baking sheet 2, facing the inductor hearth.
• the hob has two parts of different materials:
• a first part 21 has a hole 22 whose size is greater than the diameter of the inducing focal point, so as to leave this focal point fully appear when the first part is put in place.
• this first part is molded, by injection or by compression, in a heat-resistant material.
• the material used for molding is a thermoplastic, preferably loaded by mineral particles (glass fibers, silica), in order to avoid molding imperfections.
• thermosetting which has very high mechanical stability and thermal compared to a thermoplastic material.
• the hob according to the invention comprises also a second part 20 made of glass, intended to carry the container to heat.
• This second part is dimensioned at the surface so as to completely cover the hole 22 of the first part 21.
• the thickness of the second part is determined so as to optimize the heating of the container 1 by induction, the inducing focus being over its entire surface in contact with the lower part of this second part.
• the glass used can be a conventional glass ceramic. In this case, we reduced the amount of material needed compared to the tables in glass ceramic known, and therefore, the total cost of the device.
• a glass is used soda-lime, type of glass generally used to make windows.
• soda-lime glass can advantageously be tempered so as to to improve its resistance to mechanical shock.
• a temperature control device advantageously can be provided to use a temperature control device avoiding, by adjusting the power of the inducing hearth, that part 20 does not reach temperatures above a certain threshold, typically 320 ° C.
• Soda-lime and borosilicate glasses are preferable to glass-ceramic because they retain their dielectric characteristics in temperature.
• the assembly of the two parts 20, 21 must allow good sealing and take into account the different expansion coefficients of the two used materials :
• the first part 21 has a peripheral shoulder 23 on the periphery of the hole 20, on which comes to rest the second part 23.
• the two parts are by example assembled by silicone bonding, to ensure a seal maximum.
• assembly can be carried out through a seal.
• the upper surface of the second part is raised relative to the upper surface of the first part, for example of the order of 1 millimeter.
• the bottom of the container is never in contact with the heat-resistant material of the first part.
• the overall cost of a cooking appliance equipped with a plate according to the invention is significantly reduced compared to same appliance fitted with a ceramic hob (the induction cooker can be covered with a glass plate 20, much cheaper than the glass-ceramic, and the support 21 can be made of thermoplastic material or thermosetting).
• the temperature of the plate being lower that in the case of radiant elements, its dimensions can be reduced.
• the distance between the edges of the inductor hearth 3 and the support 21 can be very small (about 4 mm).
• the plate 20 exceeds by about 1 mm the level of the support 20, there is no heat exchange between them (by the vessels to be heated), which allows the support 21 made of thermosetting or thermoplastic material.
• the first part being molded functions additional devices such as the control keypad or the air outlet of cooling can be integrated directly, with searches new aesthetics, especially in terms of volume.
• Figures 2a to 2f Different geometric configurations are possible, such as show Figures 2a to 2f. (circular, elliptical shapes (Figure 2a) or square (figure 2b) for devices fitted with four induction cookers conventional, or two induction cookers for fish dishes ( Figures 2c to 2 F)).

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Family Applications (1)

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Cited By (3)

Citations (8)

• 1994
  • 1994-11-04 FR FR9413195A patent/FR2726634B1/fr not_active Expired - Fee Related
• 1995
  • 1995-11-03 DE DE1995614079 patent/DE69514079T2/de not_active Expired - Fee Related
  • 1995-11-03 EP EP19950402455 patent/EP0711098B1/de not_active Expired - Lifetime

Patent Citations (8)

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