| 摘要 |
PROBLEM TO BE SOLVED: To provide a submerged pump miniaturizing a water level detection sensor and preventing erroneous operation due to attached matter on a detection electrode without providing a grounding electrode. SOLUTION: The submerged pump has a capacitance sensors 11, 12 attached on a attachment rod 9 extending in an up-and-down direction and supported by a pump body 1a, and is driven and controlled according to detection or non-detection of water level by the capacitance sensors 11, 12. The capacitance sensors 11, 12 are provided with detection electrodes 11a, 12a for detecting the water level and oscillation circuits 11b, 12b liquid-tightly covered by insulating material. The water level is detected by detecting change of stray capacitance 20, 21 between the detection electrodes 11a, 12a and oscillation circuits 11b, 12b or capacitance of the detection electrodes 11a, 12a themselves. COPYRIGHT: (C)2007,JPO&INPIT
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