| 摘要 |
PURPOSE:To accurately measure an ultrasonic wave propagation body distance even if the kind of an ultrasonic wave propagation medium or temperature is changed by arranging an ultrasonic wave reflection body and an ultrasonic sensor for sound velocity measurement in a container at a specific distance and calculating the sound velocity in the ultrasonic wave propagation medium. CONSTITUTION:When a water distance is measured, a water distance calculating means 6 is controlled to emit ultrasonic waves from an ultrasonic sensor 3 for water distance measurement and ultrasonic sensor 4 for sound velocity measurement and the ultrasonic sensor 3 for water distance measurement detects an echo reflected by the internal surface of a pipe 1 and the ultrasonic sensor 4 for sound velocity measurement detects an echo reflected by the ultrasonic wave reflection body 5. The sensor 4 counts the time t1 of reciprocal propagation of a distance l1 to the reflection body 5 and the sound velocity V in water as the ultrasonic wave propagation medium is calculated from the time t1 and distance l1. An ultrasonic wave propagation medium distance measuring means 63 calculates the water distance l2 based on the sound velocity V and the time t2 from the ultrasonic sensor 3 for water distance measurement. |
