| 摘要 |
PURPOSE:To detect a level height of liquid unaffected by dimensions and construction of a liquid reservoir, condition in the reservoir, classification and characteristic of the liquid, by introducing supersonic wave from outside surface of the reservoir wall and detecting the liquid level inside the reservoir by comparing damping rates of the reflected wave. CONSTITUTION:Regarding a sound pressure reflecting rate of a supersonic wave, when the supersonic wave (Longitudinal wave) is projected vertically onto the border surface 5 of reservoir wall S and air A, the sound pressure reflecting rate RA reaches 99.9981%. This represents approximate total reflection on this surface 5. On the other hand, the sound pressure reflecting rate RW for vertical irradiation of the supersonic wave (Longitudinal wave) onto the border surface 6 of reservoir wall S and water W reaches 93.7684%. As the sound pressure is proportional to the height of echo appearing on CRT, when values of RA and RW are compared, the comparison value h becomes 0.559dB. When the echo heights of multiple recting waves are compared, every reflection accumulates the difference of echo heights by 0.559dB and thus, detection of the water level 2 becomes available. |
