| 摘要 |
A system for control of domestic heating appliances, such as electric kettles, using temperature measurements of the appliance where the rate of change of the temperature with respect to time is calculated and compared to a threshold. If the rate is above the threshold, the heater power is switched off thus avoiding dry-boiling or dry-burning of the appliance, such as when too little or no water is put in the kettle. Preferably the second differential may also be calculated and compared to a threshold if the first differential is less that a threshold, and the heater power turned off if the second differential is above the threshold. A maximum temperature limit and maximum heating time limit may also be set and if either is exceeded, the heater is switched off. |
