Research On Internal Leakage Detection Technology Of Natural Gas Pipeline Valve Based On Acoustic Emission

Through extensive investigation of valve leakage in natural gas field,we found that the main leakage valves are the ball valves and plug valves.Once there is a valve leakage,it will cause huge economic losses and even harm personal safety,so the effective detection of the valve leakage is of great significance.The following research is carried out in this paper based on the original research:?1?Acoustic emission detection technology has been proved to be applied to natural gas valve leakage detection by investigating the domestic and foreign development status of valve leakage detection technology and analyzing the advantages and disadvantages of different valve inner leakage detection methods.?2?The main noise source and its sound field characteristics are introduced.The valve size?D?and the internal leakage flow?Q?,(AE_rms)and the pressure difference?P?of the valve are deduced according to the Leithi equation and the U8 law,and then the valve leakage flow forecasting model is obtained.?3?The valve is easy to generate mechanical noise in the piping,regulating pry and elbow.In this paper,the wavelet packet threshold method is used to reduce internal leakage noise of the valve.The original signal of the internal leakage of the valve is obtained and it lays the foundation for the quantitative detection of acoustic leakage.?4?Developing of an integrated valve leakage detection device and its supporting software,at the same time,managing ball valve and plug valve leakage model data through Access database to meet the situation testing requirements.?5?The source of the valve internal leakage characteristic database has been introduced and the indoor 3-inch ball valve and the plug valve detection experiment platform has been built.Through the indoor test,the inner leakage sample database is improved and the accuracy of the prediction model is tested and verified.It has been proved that the newly developed instrument can detect the valve leakage effectively and qualitatively through extensive field test.