Patent ID: 6094987
Filing Date: 2000-08-01
Classification: G01H

Abstract:
A method for ultrasonic wave measurement, in which first and second ultrasonic sensors are arranged to face each other, and these first and second ultrasonic sensors are respectively provided with first and second reflectors on their surfaces, and further, an interval between these reflectors is set as a distance L, comprising the steps of:measuring a time t.sub.1 until an ultrasonic wave transmitted from the first ultrasonic sensor is received in the second ultrasonic sensor, a time t.sub.2 until the ultrasonic wave transmitted from the first ultrasonic sensor is reflected by the second reflector, and is received by the first ultrasonic sensor, a time t.sub.3 until the ultrasonic wave transmitted from the second ultrasonic sensor is received in the first ultrasonic sensor, and a time t.sub.4 until the ultrasonic wave transmitted from the second ultrasonic sensor is reflected by the first reflector, and is received in the second ultrasonic sensor, within a medium subject to measurement; anddetermining a propagation time t.sub.t of an ultrasonic wave in the distance L within the medium subject to measurement from the following equation t.sub.t =(t.sub.4 -t.sub.3 +t.sub.2 -t.sub.1)/2 and an absolute sound velocity V of the medium subject to measurement from the following equation V=L/t.sub.t.