| 摘要 |
PURPOSE:To prevent the effect of the waving of a liquid, by providing a wave transmitter and a wave receiver so that they are submerged in the liquid when the liquid level is higher than a specified liquid level. CONSTITUTION:An ultrasonic wave transmitter T and an ultrasonic wave receiver R are provided at position relationship in a tank (t) so that a wave transmitting front f1 does not face a wave recieving front f2. When the wave teansmitter T and the wave receiver R are submerged in a liquid in the tank (t), a radiation direction angle from the wave transmitter T is broad in the liquid and the wave is propagated in the liquid without attenuation. Thus the wave can be received by the wave receiver R. When the liquid level l in the tank (t) becomes lower than the wave transmitter T or the wave receiver R, which is located at a higher position. The wave cannot be received by the wave receiver R. Therefore, whether the liquid level is located higher than a specified liquid level l or not is detected. |
