| 摘要 |
PURPOSE:To eliminate an error in detection and to improve the degree of freedom of a fitting position by guiding an ultrasonic wave which is emitted by an ultrasonic wave transmitter/receiver to a liquid surface to be detected through a guide pipe and receiving its reflected wave through said pipe. CONSTITUTION:The ultrasonic wave transmitter receiver 7 emits the ultrasonic wave from one end side of the guide pipe 8 according to a signal outputted by an ultrasonic wave oscillation means and then the ultrasonic wave is guided through the pipe 8, guided up to the liquid surface 3 to be detected, and reflected. The reflected wave is passed through the pipe 8 again and received by the transmitter receiver 7. Then a signal processing means measures the required time from the emission to the reception to calculate the distance L1 from the transmitter/receiver 7 to the liquid surface 3a. Then the level L of the liquid surface 3a is measured according to the result. The pipe 8 is made of rubber, synthetic resin, etc., and its internal diameter is determined corresponding to the frequency of the ultrasonic wave. Thus, an external noise signal is cut off and fluctuations of the liquid surface 3a based upon the waving of liquid 3 to be detected are reduced, so the error in detection is reduced. |
