摘要 |
An immersion heater is disclosed having a heating member with a small thickness and comprised of PTC thermistor material. The heating member has the same heat contact between each of its two major surfaces and the medium to be heated. A Curie temperature TC and a specific resistance rho TC of the material are dimensioned such that with a given operating voltage U a temperature regulation for the range with the positive temperature coefficient of the material results. By use of the upper limit of the Curie temperature TC, extensive protection against fire can be obtained in the case of inappropriate handling of the immersion heater. |