Patent ID: 6304514
Filing Date: 2001-10-16
Classification: G01B,G01N

Abstract:
An ultrasonic measuring apparatus with transmitter and receiver for locating the geometrical position of the boundary between a first and a second material by measuring and comparing the propagation times required for return to the receiver by an ultrasonic signal (US.sub.R) emitted by the transmitter and reflected at the boundary to the first material and an ultrasonic signal (US.sub.2) reflected at the boundary to the second material, characterized in that from the ultrasonic signal (US.sub.S) received by the receiver the ultrasonic signal (US.sub.2) reflected at the boundary to the second material is isolated by forming the difference between the ultrasonic signal (US.sub.S) received and a reference signal (US.sub.2) corresponding to the ultrasonic signal (US.sub.R) reflected at the boundary to the first material, and the propagation time of the ultrasonic signal through the first material is determined from the time (t.sub.2) up to the first rise in the reference signal (US.sub.2) and the time (t.sub.1) up to the first rise in the received ultrasonic signal (US.sub.S).