| 摘要 |
<p>PURPOSE:To easily detect the position of objects by measuring the propagation time and waveforms of the acoustic waves transmitted in plural directions from the ultrasonic oscillators or objects embedded in respective flow passages in which the objects are embedded by successively changing the directions where the acoustic waves are received and comparing the measured values with the preset position of the object and transmitting time of the acoustic waves. CONSTITUTION:The ultrasonic oscillators 3 are embedded in the peripheral parts of the runner cone parts 2 of runners 1 of a water-wheel so as to face the outlets 5a thereof for each of the flow passages 5 of the runners 1. The waves are transmitted and received while the respective ultrasonic oscillators 3 are driven by successively changing the directions where the acoustic waves are received. The waveforms of the signals received from the respective ultrasonic oscillators 3 are compared at all times with the waveforms of the signals received just before this reception. Namely, the waveforms of the received signals vary with whether a robot 4 for inspection is inserted into the flow passage 5 or not; therefore, the presence of absence of the robot 4 for inspection in the flow passage 5 is decided by measuring the correlations of the respective waveforms.</p> |
