Method for detecting defects in a tube heat exchanger
A method for maintaining a tube heat exchanger includes: obtaining measurement signals resulting from the passage of a measurement probe in the tubes of the heat exchanger, determining a reference time series corresponding to an average, at each instant, of the measurement signals, synchronising each measurement signal with the reference time series by applying a dynamic time warping, DTW, to said measurement signal and the reference time series, and searching for a potential anomaly by measuring a potential local deviation of a measurement signal with respect to the other measurement signals.
1 . A method for maintaining a tube heat exchanger, comprising:
obtaining measurement signals resulting from the passage of a multifrequency eddy-current measurement probe in the tubes of the heat exchanger, wherein each measurement signal is a multidimensional time series comprising P components, P being a natural integer greater than or equal to 2,
determining by a processor of a computer a reference time series corresponding to an average, at each instant, of the measurement signals and comprising P components,
synchronising each measurement signal with the reference time series by applying a dynamic time warping, DTW, to said measurement signal and the reference time series multidimensionally on the P components simultaneously, and
searching for a potential anomaly by measuring a potential local deviation of a synchronised measurement signal with respect to the other measurement signals synchronised with the reference time series.
2 . The method according to claim 1 , wherein the search for a potential anomaly is carried out component by component by the processor of the computer.
3 . The method according to claim 1 , comprising a selection, among the measurement signals, of measurement signals resulting from the passage of a measurement probe in the tubes belonging to a subset of tubes grouped according to the similarity of their physical properties by the processor of the computer.
4 . The method according to claim 1 , wherein the search for a potential anomaly by measuring a potential local deviation of a measurement signal with respect to other measurement signals comprises determining by the processor of the computer a distance between a value of the measurement signal and the corresponding values of other measurement signals.
5 . The method according to claim 4 , wherein a median filter is applied by the processor of the computer to the distances determined during the search for anomalies.
6 . A non-transitory computer-readable medium, comprising program code instructions for causing a computer to execute the steps of the method according to claim 1 , when said program is executed by the computer.