(under subclass 497) Subject matter wherein the resistance heating element of the immersion heater increases its resistance as the temperature increases.
SEE OR SEARCH CLASS
219, Electric Heating,
504+, for variable resistance means and subclasses 552+ for heating element structure.
338, Electrical Resistors,
22+, for thermistor type and subclasses 25+ for ambient temperature.
374, Thermal Measuring and Testing, 183+, for current modifying sensor and, particularly, subclass 185 for detail of resistive sensor.
