Electrical heating element
AssigneeVacuumschmelze GmbH & Co. KG
InventorsHartwin Weber, Waldemar Doering
Life of this patent
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Abstract
An electric heating element is provided with a durable PTC resistance made at least partially of an iron-based alloy, exhibiting stable characteristics to a temperature of 1500 DEG C. and having a resistance/temperature characteristic curve which substantially increases in a linear manner within a temperature range between an ambient temperature and 1500 DEG C. and can be used for a temperature control. The PCT resistance is provided with an oxidation resistant metallization or is gas-tightly enveloped by a jacket (2, 3, 12), a space between the jacket (2, 3, 12) and the PCT resistance (1,13) being filled with a powder or granules (14) which remove an important gas amount from the space.
Claims22
An electrical heating element with a PTC resistor intended for heating and regulating made at least partially of an iron-based alloy, comprising
- continuous and constant properties when operated up to 1,500° C. and does not have any crystallographic grid conversions, and
- a resistance/temperature curve rising in the temperature range between room temperature and 1,500° C., and the rise of which in the temperature range between room temperature and about 750° C. is so steep that the temperature of the PTC resistor can be set to a target temperature using its own temperature behavior.
A method of using an electrical heating element in a glass ceramic cooking element, comprising the steps of:
- providing a PTC resistor intended for heating and regulating made at least partially of an iron-based alloy, comprising continuous and constant properties when operated up to 1,500° C. and does not have any crystallographic grid conversions, and a resistance/temperature curve rising in the temperature range between room temperature and 1,500° C., and the rise of which in the temperature range between room temperature and about 750° C. is so steep that the temperature of the PTC resistor can be set to a target temperature using its own temperature behavior;
- providing a space between an upper cover plate and a lower cover plate,
- inserting the PTC resistor in the space, and
- sealing the space gastight.
Dependencies are inferred from the claim text.