| The pilot-operated pneumatic pressure reducing valve is a pneumatic control elements that uses compressed air as drive medium to provide stable working pressure by the feedback of the pilot structure.The pilot-operated pneumatic pressure reducing valve can adapt to the volatility of pneumatic system,which is widely used in general industrial gas occasions and has become one of the important research directions of pneumatic technology.This thesis presents a kind of pilot-operated pneumatic pressure reducing valve which apply to ordinary industrial gas application.Firstly,the structure type is internal pilot to reduce the volume due to the miniaturization,modularity can reduce costs and facilitate the replacement of parts of the pressure reducing valve.Secondly,the overall structure of the pressure reducing valve and the structure design of the pilot valve components and main valve components are proposed,the filter throttle screw and the exhaust bolt are designed.Then,the physical model of the pressure reducing valve is obtained,the whole lumped parameter equation of the pressure reducing valve is created based on MATLAB/Simulink,and analyze the reasons that influence stable working condition and dynamic pressure regulation of the pneumatic system to get the action laws of the parameters.Finally,the test of the pilot-operated pneumatic pressure reducing valve is designed and conducted,and the test results show that the maximum working flow up to 2000L/min of the designed pilot-operated pneumatic pressure reducing valve.The main research contents of the thesis are as follows:Chapter1,the types of the pneumatic pressure reducing valve are described,the research status of the pneumatic pressure reducing valve is summarized,the key and main research contents in this thesis is sketched.Chapter 2,the main components and working principle of the designed pressure reducing valve is described minutely,the structure of the pilot-operated pneumatic pressure reducing valve is analyzed and designed by the technical indicators of the pneumatic system,and the sealed form of the pilot-operated pneumatic pressure reducing valve is determined.Chapter 3,the mathematical model of pilot components and main valve diaphragm and stem-spool assembly of the pilot-operated pneumatic pressure reducing valve is established through the force analysis of the pilot components,the main valve diaphragm,stem-spool assembly.And the factors that affect the performance of the pilot-operated pneumatic pressure reducing valve is obtained by thermodynamic theory which describes the pressure-temperature differential equation of each gas chamber system in the pressure reducing valve.Chapter 4,the lumped parameter differential equation of the designed pressure reducing valve is built,the influence of the parameters such as the inlet pressure,orifice diameter,feedback hole diameter,main valve port diameter,and control air chamber initial volume to the performance of the pressure reducing valve are analyzed based on MATLAB/Simulink.Chapter 5,the basic principle of the output pressure test system and the flow rate test system are introduced.Based on these test system,selecting the test equipment to test the performance of the pressure reducing valve,and the consistency between the simulation results and the experimental data proves the accuracy of the simulation model.Chapter 6,the main contents of in this thesis are summarized,and the further research work is prospected. |
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