Diagnostic methods of obstruction foreign body position in the pipe

摘要

PROBLEM TO BE SOLVED: To provide a method for diagnosing a blocked foreign matter position in a piping for diagnosing a position where blocked foreign matters are deposited in the piping.;SOLUTION: A drain piping is vibrated by striking the outer surface by an impact hammer with a built-in load sensor. This vibration is measured by an acceleration sensor installed in the drain piping to be input to an FFT analyzer as a vibration signal. The FFT analyzer calculates a transfer function on the basis of the vibration signal and striking force to the drain piping measured by the load sensor. A signal processor calculates a mode attenuation ratio of a natural vibration mode by using the transfer function (S1), and determines whether or not the mode attenuation ratio is equal to or more than a reference mode attenuation ratio (S2). When this determination is YES, wavelet transform is performed to an acceleration time history waveform measured by the acceleration sensor (S5) to create display information of a time-frequency waveform of the acceleration time history waveform (S6). A blocked foreign matter position is diagnosed on the basis of the display information.;COPYRIGHT: (C)2014,JPO&INPIT