| 摘要 |
PURPOSE:To enable highly accurate detection of a liquid amount by measuring a time difference between a supersonic wave generated from a supersonic wave sensor and a wave reflected from a water surface, and to calculate the liquid amount from the time when the water surface is stabilized. CONSTITUTION:A transmitting means 9 applies a high-frequency signal to a supersonic wave sensor 5. A receiving means 10 inputs a reflected signal received by the supersonic sensor 5 to output an amplified and shaped wave form. A time measuring means 11 measures a time taken from the transmission of the transmitting means 9 to the reception of the receiving means 10. A water surface stableness judging means 15 detects predetermined number of times measured by the time measuring means 11 to judge the stableness or unstableness of the water surface from the dispersion during the detecting time. A liquid amount calculating means 12 calculates the liquid amount from a time measured by the time measuring means 11 when the water surface is judged to be stabilized by the water surface stableness judging means 15. Thus, the liquid amount can be measured with higher accuracy than the conventional one. |
