METHOD AND APPARATUS FOR MEASURING POSITION OF BOUNDARY OF DIFFERENT SUBSTANCES BY ULTRASONIC WAVE

摘要

PROBLEM TO BE SOLVED: To provide a boundary position measuring method for measuring the distance to the boundary of different types of substances, from the time taken by propagation of ultrasonic waves reflected from the boundary of different types of substances and the acoustic velocity of ultrasonic waves corrected corresponding to the degree of deterioration of a medium, in the ultrasonic waves propagating in the medium. SOLUTION: The propagation time of longitudinal and transverse ultrasonic waves in a surface-reformed layer 4a is obtained by a part 6 for measuring the time taken to propagate reflected waves received by an ultrasonic sensor 1. The acoustic velocity corrected corresponding to the degree of deterioration is calculated by an acoustic velocity correcting apparatus 7 based on the correlation of the degree of the deterioration of a corrected data recording part 8a and the acoustic velocity ratio. The position of the boundary is calculated by the boundary position calculating apparatus 9, which calculates the boundary position from the corrected acoustic velocity and the propagation time.