Patent ID: 8966979
Filing Date: 2015-03-03
Classification: G01B,G01H,G01N

Abstract:
1. A method of measuring the thickness of a deposit of material on an inner wall of a structure, the method comprising: (a) heating a portion of the structure; (b) detecting vibrations at the heated portion; (c) detecting vibrations at an unheated portion of the structure; (d) determining a resonance frequency or frequencies of the structure at the unheated portion of the structure based on the vibrations detected at (c); and (e) determining the thickness of a deposit of material on the inner wall of the structure at said unheated portion using the determined resonance frequency or frequencies at the unheated portion of the structure, wherein the detected vibrations of step (b) at the heated portion are used for calibrating the detected vibrations at the unheated portion of step (c) before steps (d) and (e) are carried out.