Pilot Diaphragm Pneumatic Valve Excitation Factors Theoretical Analysis And Experimental Research

A new series of pneumatic pressure relief valve with film pilot possesses excellent static characteristics. But at present there is some vibration phenomena when a series of pressure relief valve called QJY is working. This vibration influences pressure stability and working environment severely. This paper is aiming to find out the factors that produce vibration of pressure relief valves and provide the foundation for improving structure, eliminating vibration and optimizing design in the future.In this paper, the preliminary mathematical model is established based on the analysis of the structure and working principle of pressure relief valves, then the dynamic simulation of the valve is done by the means of MATLAB/Simulink. The result of the simulation indicates that the vibration of pressure relief valves is the comprehensive effects of various factors. Simultaneously, the vibration of pressure relief valves can be reduced by increasing output-cavity volume, reducing effective throttle area from input-cavity to top-cavity and reducing the hatch diameter of the main valve, etc.For the sake of finding out the factors that produce pressure relief valve vibration, the experiments on the Valve-body and the valve-core of the pressure valve are carried out respectively. The result of experiment indicates that the main valve-core's vibration and the pilot valve-core's stir up the pressure relief valve's vibration . Therefore, only the structure of the nozzle plank in the pilot area is improved without other structure of the pressure relief valve changed. The result of experiments with improved nozzle plank shows that the vibration phenomena are reduced. Thus, the valve-core of pilot valve's vibration is the main reason that stirs up the pressure relief valve's vibration.