| 摘要 |
PURPOSE:To detect precisely temperature differences at respective parts of a tank and to prevent securely a tank rollover, by leading out the temperature differences between detection outputs of couples of sensors provided at the respective parts in the tank and reference sensors provided to a float corresponding to them. CONSTITUTION:The sensors 4A-4N are provided at equal intervals from the alpha bottom surface to the ceiling in the tank and the reference sensors 6A- 6N are provided to the float 5 in a boundary surface which is not influenced by external temperature; they correspond to each other. Each sensor is a resistance temperature detector and varies in resistance value with temperature to generate a voltage; the sensor 6 and sensors 4 form a current loop from a constant current source. A processor 7 scans on every couple of the reference sensor 6 and sensor 4 successively to amplify and read its temperature difference voltage. Therefore, the measurement has high resolution and high precision and the tank rollover is prevented automatically to control the tank in safety. |
