Stoves and furnaces – Stove lids and tops – Liquid or gaseous fuel
Patent
1997-12-02
1999-08-03
Dority, Carroll B.
Stoves and furnaces
Stove lids and tops
Liquid or gaseous fuel
126 39R, 126214A, F24C 1510
Patent
active
059311525
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a glass-ceramic gas cooking plate and to a process for manufacturing it.
The market of cooking plates which can be fixed in or which are integrated in kitchen ranges includes essentially three types of products: gas flame plates, electric plates made of cast iron, and glass-ceramic plates.
The gas flame cooking plates consist of a plate, generally made of enamelled sheet metal, of burners emerging from this plate, and of supports for cooking articles resting on this plate.
Recent efforts have renewed the appearance of these cooking plates by replacement of the traditional enamelled sheet metal by glass or glass-ceramic plates. However, these innovations have not modified the old design of the gas flame plate which includes a plate, burners, and supports for the cooking utensils.
The electric plates made of cast iron have allowed electrical energy to be used for cooking, but since the advent of glass-ceramic cooking plates, they have been confined to bottom-of-the-line electric cooking plates.
The glass-ceramic cooking plates occupy a predominant place in the market of cooking plates and represent modernity and the top of the line with regard to cast iron electric plates and the gas flame plates. The qualities recognized by consumers are ease of cleaning due to the continuity of the glass-ceramic plate as well as the modern appearance of these surfaces, which are black in color in almost all cases. The glass-ceramic plates use several systems of heating. Heating by radiant or halogen electric ranges is the most widespread, but requires several kilowatts of power, which are not always available on the electrical networks of a number of countries including Italy and to a lesser extent Spain. For these countries, systems of heating with gas with no visible flame, placed under the glass-ceramic plate, have been developed in order to replace electric ranges.
Heating of cooking articles using flameless gas ranges or radiant or halogen electric ranges, because the transfer of heat to said articles occurs through the glass-ceramic plate, involves preheating of the plate. Systems of heating by induction under the glass-ceramic plate allow one to heat the cooking utensil directly without heating the glass-ceramic plate, but they require specific cooking articles (which are conductive and preferably magnetic).
The use of lithium aluminosilicate glass-ceramics has allowed for the development of glass-ceramic cooking plates due to their very low expansion coefficient which allows them to resist thermal shocks of several hundred degrees.
Let us recall that a glass-ceramic is originally a glass, called precursor glass, whose specific chemical composition makes it possible to bring about a controlled crystallization by suitable thermal treatments called ceramic processing treatments. This specific structure which is partly crystallized gives the glass-ceramic unique properties. During ceramic processing treatments, the following phases are generally observed: a nucleation phase during which the nuclei on which the crystals will form coalesce, and a crystallization phase during which the crystals form and then grow. The viscosity of the glass decreases during the initial heating, has a minimum value just before crystallization, and then increases under the effect of crystallization. Nucleation takes place at around 700.degree. C. Ceramic processing into transparent material occurs at around 900.degree. C., whereas ceramic processing into opaque material takes place at around 1100.degree. C., with opalizing beginning at around 1000.degree. C.
Various material belonging to the family of the lithium aluminosilicate glass-ceramics are used as support for cooking articles: .beta.-quartz glass-ceramics, black in appearance, slightly transparent in the visible, and to varying degrees transparent in the infrared, and .beta.-spodumene glass-ceramics, white in appearance, opaque in the visible, and slightly transparent in the infrared. Because of their optical properties, the use of .beta.-spodumene glass-cer
REFERENCES:
patent: 4458661 (1984-07-01), Mulay
patent: 4835121 (1989-05-01), Shibuya et al.
patent: 5212122 (1993-05-01), Pannhorst et al.
patent: 5313929 (1994-05-01), Thurk et al.
patent: 5549100 (1996-08-01), Heisher et al.
Fafet Gerald P.
Fredholm Allan M.
Dority Carroll B.
Eurokera
Nwaneri Angela N.
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