| 摘要 |
PURPOSE:To easily and precisely detect a liquid level position even in case of a deep tank by generating a standing wave with a sound wave of a fixed frequency from one opened end side of a pipe having the other opened end part dipped in a liquid in the tank. CONSTITUTION:In a cylindrical body 9 having both the ends opened, one end part is fixed to the upper wall surface of a tank 5 and suspended from the wall surface, and the other end part is extended close to the bottom surface of the tank 5 and regularly dipped in a liquid 6. A speaker 1 is mounted to clog the upper end opening part, and a small diameter air hole 9a is provided on the upper end part of the cylindrical body 9. The speaker 1 generates a sound of a fixed frequency into the cylindrical body 9 to generate a standing wave with the liquid 6. On the basis of the acoustic impedance of the speaker 1 corresponding to the generation of the standing wave according to the liquid level position of the liquid 6, the liquid level position is calculated by a counter. |
