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AssigneeE.G.O. Elektro-Geraetebau GmbH
InventorsLutz Ose, Eugen Wilde, Willi Essig
Estimating the term…
On the one hand is provided an electric heating element (15, 31) consisting of a semiconducting ceramic (28, 32) as well as a method for its production. The semiconducting ceramic material may be porous or foamed to thus contain pores (29, 34) open outwardly. The pores are attainable by admixing filler bodies, which dissolve during sintering, to the starting material or by impreganting a textile substrate material (36) with a ceramic material. Due to the porosity of the heating element (15, 31) an increased radiant surface area is attained. On the other hand is provided an electric heating element (115, 132, 145, 150, 158, 160, 162) as well as a method for its production which consists of semiconducting ceramic and comprises a negative temperature coefficient of the electrical resistance. The temperature coefficient is negative throughout over the full operating temperature range. The material suitable for the heating element (115, 132, 145, 150, 158, 160, 162) is doped silicon carbide or TiN. One such heating element (115, 132, 145, 150, 158, 160, 162) may be put to use, for example, rod-shaped in a radiant heater body (111) or foil-shaped at the underside of a surface element (30) of a cooktop (31). The electric conductivity of the material of the heating element (115, 132, 145, 150, 158, 160, 162) can be adjusted by nitrogen absorption during annealing in a nitrogen atmosphere subsequent to the sintering process.
An electric heating element (15, 31) made of a semiconducting ceramic wherein said semiconducting ceramic material comprises cavitations (29, 34) at least in part.
A method of producing an electric heating element (15, 31) consisting of a semiconducting ceramic comprising the steps:
An electric heating element (15, 32, 45, 50, 58, 60, 62) consisting of semiconducting ceramic wherein said heating element (15, 32, 45, 50, 58, 60, 62) comprises a negative temperature coefficient of its electrical resistance.
A method of producing an electric heating element (15, 32, 45, 50, 58, 60, 62) having an inherently negative temperature coefficient of said electrical resistance of said heating element (15, 32, 45, 50, 58, 60, 62) consisting of a semiconducting ceramic which for attenuating said negative temperature coefficient is doped with a dopant, nanoparticles being contained in said starting material by means of which the residual porosity of said ceramic after the sintering process of said starting material is adjustable, said residual porosity serving diffusion or doping with a dopant.
An electric heating means (11) including an electric heating element (15, 32, 45, 50, 58, 60, 62) comprising a negative temperature coefficient of its electrical resistance, said heating means comprising assigned to said heating element (15, 32, 45, 50, 58, 60, 62) a temperature sentinel (25, 26) including control means for influencing said heating element (15, 32, 45, 50, 58, 60, 62).
Dependencies are inferred from the claim text.