37 A Method of Vacuum Leak Detecting Based on Acoustic Emission …
425
(a)1.0 mm
(b)1.5 mm
(c)2.0 mm
Fig. 37.6 The acoustic emission signals of three different leak holes
The commonly used characteristic parameters of continuous acoustic emission
signals are including signal amplitude (Amplitude), average signal level (ASL),
signal energy (Energy), root mean square of signal voltage (RMS) and so on. To
increase the stability of feature parameter identification of different leak signals, the
signal is first filtered by 20–250 kHz. Then, the collected leak signals with a total
length of 8 ms are divided into 25 segments. The analyzing results are shown in
Fig. 37.7. As can be seen from the figure, all of the four parameters is able to distinguish three different kinds of leak effectively, and the results are more stable and
clear by using the ASL, Energy and RMS parameters.
425
(a)1.0 mm
(b)1.5 mm
(c)2.0 mm
Fig. 37.6 The acoustic emission signals of three different leak holes
The commonly used characteristic parameters of continuous acoustic emission
signals are including signal amplitude (Amplitude), average signal level (ASL),
signal energy (Energy), root mean square of signal voltage (RMS) and so on. To
increase the stability of feature parameter identification of different leak signals, the
signal is first filtered by 20–250 kHz. Then, the collected leak signals with a total
length of 8 ms are divided into 25 segments. The analyzing results are shown in
Fig. 37.7. As can be seen from the figure, all of the four parameters is able to distinguish three different kinds of leak effectively, and the results are more stable and
clear by using the ASL, Energy and RMS parameters.