The Research On Fault Diagnosis Of Gas Source And Internal Leakage Of Control Valve

Pneumatic control valve is often used to regulate the pressure and flow of various media,in the maintenance of stability,process safety and optimization control plays a vital role.With the development of industry,more and more industrial equipment and modern control process are becoming more and more complicated,more and more types of pneumatic control valves are applied in industrial process control.Because of the bad working environment of control valve,the control valve frequently moves for long time,so control valve prone to a variety of faults,in the event of failure,it may lead to waste of raw materials,environmental pollution and even more serious production accidents.Therefore,the research on the fault diagnosis of pneumatic control valve is of great significance to the safety,stability and high efficiency of industrial processes such as chemical industry and electric power.In this paper,the method of signal processing is used to detect the fault of gas source,and the control valve internal leakage fault diagnosis is realized by using the method of comparing characteristic coefficients.The main contents of this paper are as follows:The empirical modal decomposition(EMD)is introduced into the fault detection of gas source.In order to obtain the fault data,this paper constructs the experimental platform and simulates the gas source leakage fault,realize the automatic detection of the gas source fault by using the EMD to decompose the experimental data,the experimental results verify the effectiveness of the method.Hilbert vibration decomposition(HVD)is applied to fault detection of air source of pneumatic control valve.EMD realizes the detection fault of gas source,but EMD has end point effect in the process of decomposition,which introduces HVD and the simulation shows that HVD avoids the endpoint effect,and the experimental results show that it can effectively detect gas leakage failure.In this paper,the simulation experiment of internal leakage of control valve is carried out by using the Enterprise Flow table.By using Lab VIEW acquisition system,the pressure difference and flow data of the solid valve are collected and calculated and analyzed,and the internal leakage failure and the failure strength are detected by comparing the flow characteristic curves of the control valves in different states.The method of signal analysis is often applied to the fault diagnosis of rotating machinery,this paper firstly introduces the method of EMD and HVD signal analysis into the fault diagnosis of the control valve,and realizes the gas source fault detection,which has some innovative significance.It is of great practical value to realize the fault diagnosis of the internal leakage of control valve based on the flow coefficient,which provides the reference for the control valve on-line fault diagnosis.