Liquid Pipeline Valve Leakage Non-Intrusive Monitoring System Design

Valve is control device of the fluid pipe, it's one of the most widely used general machinery parts in petrochemical industry field. In industrial applications, valve has the characteristics of large amount, frequent operation and so on. Due to reasons such as corrosion, wear and improper maintenance, leakage phenomenon often appear. The valve in the pipeline system control cut-off and circulation of the fluid, the valve leakage cause waste of resources, environmental pollution and even cause fire, explosion and other accidents.Valve internal leakage cause the medium pressure disturbance on both sides, the intervention type liquid pipeline valve leakage monitoring system designed in this paper uses dynamic pressure sensor to detect pressure disturbance signals. Leakage monitoring system mainly includes field instruments, data acquisition terminal and the monitoring server. Field instrument include transmitter and install fixtures, field instrument detect dynamic pressure signal and output current signal. The current signal transmitted to data acquisition terminal through the cable. Data acquisition terminal has the functions of real-time multi-channel signal acquisition, temporary data storage and network transmission, etc. The data acquisition terminal is developed based on ARM processor. It collect multiple output signal, then transmit the signal to the server through the network. The diagnostic application in the server diagnosis based on the signal.The time and frequency domain analysis to the signal under different conditions shows that the kurtosis and energy spectrum changes when the valve leakage occurs. Using the method of wavelet packet decomposition, analysis of the reconstructed signal kurtosis characteristics, so as to extract the signal feature vector. Using PCA-SVDD method to establish valve leakage diagnosis model. The valve leakage diagnosis algorithm dynamic library and valve leakage monitoring application is developed to achieve the real-time diagnosis and monitoring of the valves.The Valve leakage monitoring system has been verified in a petrochemical plant experiment. Experimental results show that the valve leakage monitoring system designed in this paper provides a convenient, effective and reliable means of surveillance for industrial valves.