METHOD AND MEASURING ASSEMBLY FOR MEASURING LAYER THICKNESS AND SOUND WAVE SPEED IN SINGLE-LAYERED OR MULTILAYERED SAMPLES BY MEANS OF ULTRASOUND WITHOUT A PRIORI KNOWLEDGE OF THE OTHER VARIABLE

摘要

This invention is concerned with measuring the wall thickness of pipes, containers or plates (hereinafter referred to as sample) in which the inside or bottom is not accessible. In addition, the invention is concerned with the measurement of the layer thickness of coatings or linings of these samples. Special measuring arrangements are disclosed by ultrasonic transmitter and receiver in pitch-catch and pulse-echo configuration and the associated method for determining the wall thickness without prior knowledge of the speed of sound in the sample. The object of the invention is to measure the wall thickness of a sample (e.g., pipe wall, vessel wall or plate) independently of the knowledge of the speed of sound of that sample. Another object is to measure individual layer thicknesses of a multi-layer system (e.g., coated or lined pipe wall) without prior knowledge of their sonic velocities. The method and the measuring arrangement make it possible to measure the wall thickness independently of the knowledge of the speed of sound of the sample (for example, pipe wall, vessel wall or plate). This leads to a reduced measurement uncertainty of the wall thickness and inner diameter of the tube and thus to a reduced measurement uncertainty of a clamp-on ultrasonic flowmeter.