Boiling Point Detector for Surface Cooking Unit

The new type of boiling point detector is discussed which detects the boiling point of water in a container irrespective of the volume of water or the type of container. This detector consists of the sensor unit using a thermistor and the signal processor unit using a one-chip 4-b microcomputer. The sensor unit is covered with a stainless casing. It is located at the center of the coil heater and comes In contact with the bottom of the container in place. At the signal processor unit, the temperature signal from the sensor unit is applied to the integral A-D converter, and the digital value is calculated by the microcomputer to detect indirectly the temperature rise of the water in the container. The results are stored in the memory of the computer and are compared to determine the boiling point. As a result of the experiment, the boiling point detection accuracy is higher than 95°C and within 2 min after reaching 100°C when the volume of water is 0.5-2 L and the container is made of aluminum, stainless steel, or iron.