| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid level detector capable of raising accuracy of capacitance to be detected by a detection part to allow detection of a liquid level with high accuracy without complicating structure.SOLUTION: A sensor part 10 has a substrate 12, and is arranged in the vertical direction in a tank 7. On the substrate 12, five sensors 1-5 are formed like thin plates in its longitudinal direction. The sensors 1-5 are constituted of detection electrodes 1a-5a, and a grounding electrode 18, respectively, and have pieces of different electrode length with the same electrode width. A CPU 26 measures capacitance values of all the sensors 1-5 (S1) to perform processing for determining which sensors have tips between which a liquid level is positioned. For example, when the capacitance value C2 is smaller than a reference capacitance C, the CPU 26 performs liquid level calculation processing (n=2) (S3). The CPU 26 calculates a liquid level H in the tank 7 by using a capacitance value Cn, electrode length Ln, the lowest measured liquid level H, and a reference capacitance Cof a sensor n (S21). |
