Patent ID: 8661904
Filing Date: 2014-03-04
Classification: G01B,G01F,G01N

Abstract:
1. A method for investigating a structure having an inner surface interfacing a liquid or soft medium, comprising the steps of: a) exciting acoustic waves in the structure by means of at least one transmitter, b) converting at least a part of the energy associated with the acoustic waves excited in the structure into volume sound waves of the medium, c) reconverting at least a part of the energy associated with the volume sound waves into acoustic wave energy of the structure thereby generating acoustic waves in the structure, d) receiving acoustic waves evoked by the transmitter by at least one receiver, and e) verifying whether a coating is present between the inner surface of the structure and the medium and/or if a coating is present determining properties of the coating by evaluating a signal generated by the receiver upon receipt of acoustic waves evoked by the transmitter, wherein: step e) comprises evaluating a first and a second receiver signal, wherein the first signal is generated by the receiver upon receipt of acoustic waves transmitted directly from the transmitter to the receiver via the structure and the second signal is generated by the receiver due to acoustic sound waves in the medium which were induced by the acoustic waves in the structure and which travel towards the receiver, wherein the structure is a tube-like acoustic wave guide and the transmitter and receiver are arranged on the structure along a line extending parallel to a longitudinal axis of the acoustic wave guide.