Abstract
In this paper, a method to measure the pipe wall thinning in a large scale by microwaves was demonstrated. In the experiment, a microwave network analyzer was used to generate microwave signals propagating in the pipe where the frequency was swept from 47.38 to 47.47 GHz. A copper pipe having 16.26 mm inner diameter, 1 mm wall thickness, 900 mm length and with joints of thickness reductions having the length of 17 mm and thinning values of 3 to 80% wall thickness were detected significantly. By building up a resonance model, a quantitative evaluation method was established. By comparing the experimental results with those derived by the theoretical analysis, it is shown that the errors of the evaluated results are less than ± 0.5% of the pipe diameter. It indicates that high precision for remote detection and evaluation can be achieved by using this nondestructive method.
