| 摘要 |
PURPOSE: To detect the interface of a precipitation layer highly accurately regardless of fluctuation in the liquid level of a fluid. CONSTITUTION: A first distance S from a predetermined position to the liquid level 4a of a fluid 4 is determined based on the difference of time between transmission and reception of a first oscillator 1 disposed at a predetermined position above the fluid 4. A second distance L from the liquid level 4a of the fluid 4 to the interface 8a of a precipitation layer 8 is then determined based on the difference of time between transmission and reception of a second oscillator 2 floating on the fluid 4. Finally, the interface of the precipitation layer 8 is determined, along with the liquid level of the fluid 4, based on the first and second distances S, L and a fixed distance K from the precipitation starting position of the precipitation layer 8 to a predetermined position. |
