US 9,713,345 B2 · Device and method for controlling an electrical heater to limit temperature

Abstract

There is provided a method of controlling an electrical heating element, including maintaining a temperature of the heating element at a target temperature by supplying pulses of electrical current to the heating element; monitoring a duty cycle of the pulses of electrical current; and determining if the duty cycle differs from an expected duty cycle or range of duty cycles, and if so, reducing the target temperature, or stopping the supply of current to the heating element or limiting the duty cycle of the pulses of electrical current supplied to the heating element. As the temperature is maintained at a known target temperature, any variation in the duty cycle or range of duty cycles expected to maintain the target temperature is indicative of abnormal conditions.

Claims17

Dependent claims

A method of controlling an electrical heating element, comprising:

maintaining a temperature of the heating element at a target temperature by supplying pulses of electrical current to the heating element;
monitoring a duty cycle of the pulses of electrical current by determining a proportion of time that electrical current is supplied to the heating element, to provide a detected duty cycle;
and
comparing the detected duty cycle with an expected duty cycle to determine if the detected duty cycle differs from the expected duty cycle or range of duty cycles, and if so, reducing the target temperature, or stopping the supply of current to the heating element, or limiting the duty cycle of the pulses of electrical current supplied to the heating element.

1 more element

Dependencies are inferred from the claim text.

Device and method for controlling an electrical heater to limit temperature

Life of this patent

Device and method for controlling an electrical heater to limit temperature

Life of this patent

Abstract

Claims17