Design And Research On A Pressure Reducing Valve With Rapid Discharge

With the development of production technology, there are more and more new requirements of the discharge ability of a pressure reducing valve in a pneumatic system. But by now, there are no such pressure reducing valve in the market. One of the main reasons of this situation is that the structure of pressure reducing valve with rapid discharge is different from ordinary valve, which cause the other abilities of valve being uncertainly.To solve the problem, a direct-action pressure reducing valve and a pilot-operated pressure reducing valve are designed in this paper, all with rapid discharge. Also a PID-PWM control system is carried out to control the pilot-operated pressure reducing valve.The research work of this paper can be divided into the following four parts:1, Designed the structure of the valveReferencing to the size of the pressure reducing valve LR-1/4-D-O-MINI developed by FESTO, a direct-action pressure reducing falve and a pilot-operated pressure reducing valve are designed and manufactured.Carried out 3D-model of the valve with PROE software and carried out the 2D-design of the accessories with AUTOCAD.2, Set up simulink models of the valve with MATLAB and FLUENTReferencing to the results of mathematical analysis, three models are set up by MATLAB\SIMULINK and MATLAB\SIMSCAPE:(1) A static mode(2) A dynamic model(3) A discharge modelWith the static model, flow rate characteristics and pressure characteristics are analyzed. With the dynamic model, dynamic characteristic and the impact of the key parameters are analysed.With the discharge model, the discharge ability of the valve is analysed. The simulink results of discharge model indicate that the discharge ability of the designed valve is largely improved comparing to the ordinary valves of the same size.Also, a flow model of the valve is set up by FLUENT. With this model, pressure distribution, flow direction and flow velocity are analyzed.3, Designed the PID-PWM control system for pilot-operated pressure reducing valveSet up the model of PID-PWM control system with MATLABVSIMULINK and analyzed the performance of the PID-PWM system. The results of the following control signals are obtained with the simulink model:steady signal, step signal and square wave signal.4, Carried out experimentsSet up experimental platforms and developed programs for the platforms. The following five experiments are carried out in this paper:(1) Experiment to analyze flow characteristcs(2) Experiment to analyze pressure characteristcs(3) Experiments to analyze the impact of the main spring on dynamic characteristics(4) Experiments to analyze the impact of the discharge port size on discharge ability(5) Experiments to analyze the performance of the PID-PWM control systemThe results of experiments indicate that the discharge time of the valve designed has been shorten to about half of ordinary valves and the accuracy deviation of the control system for the pilot-operated pressure reducing valve has reached 1%.