Study On The Detecting System Of Acoustic Emission Of Pipeline Leakage

The leakage of pipeline is a difficult problem to pipeline transport for long,study on the theories and methods of leakage detecting and locating is significant to pipeline transport. Especially the fast development of computer technology in processing speed, combining the technology of software and virtual device with the theories and methods of leakage detecting and locating to study full digit detecting or locating system of pipeline leakage can improve the precision and reliability of leakage detecting and locating,and its flexibility is better too. The detecting of acoustic emission (AE) of pipeline leakage is a method based on the detecting of supersonic which is stimulated by the press of flowing fluid inside the pipeline when it is traveling across the body of pipeline. In this paper,the detecting and locating method by conjoining computer signal processing of leakage acoustic emission with neural net method was researched,in experience,a new method is realized on the leakage locating by wavelet disintegrating which abstracts the sub-signal in AE signal which carry the message of leakage. In detail,the following work has finished in our research.①The mechanism and features of AE wave that travels in equality-diameter pipeline are analysized,and the model of AE signal detecting is also established. At the same time,according the model,scheme of AE signal detecting is designed,the collection of AE signal is also finished.②In VC6.0 environment we develop a software system that has friendly user interface and can process the AE signal and can locate too. By this system, we analysis the features of AE signal in time field and frequency field and the relation-shipment of AE signal in detail;in test ,the adaptive filter and wavelet filter in both soft throttle and rigid throttle method have been finished.③When the condition of leakage is changed,the main band of frequency of leakage signal is also changed. In order to analysis the signal of leakage usually when the main band of frequency of leakage signal,method is used to analysis the main band of frequency by calculating the value of power spectrum and the power value of every level′s sub-signal that is abstracted from AE leakage signal by wavelet disintegrating,some parameters of filter and wavelet dividing is decided by result of the calculation,and the result of filter and wavelet dividing is better.④In the aspect of locating,the inter-relation locating and wavelet locating method...