Abstract: The extra-high pressure pneumatic on-off valve is very important part in a new pressure reducing method by expander that is used for enhancing the efficiency of extra-high pressure pneumatic power system. The operation principle and dynamic property of the valve are detailedly investigated by means of theoretical and experimental way. The problem of needing large driving power and slowing response in extra-high pressure pneumatic on-off valve is solved by means of pneumatic dynamic force balance method. A two-stage valve that used a pilot solenoid spherical valve to control a large flow-rate poppet valve is developed. The definitions and rules of dynamic processes based on the control chamber volume changing or not, and on the key pressure points in the control chamber are put forward. The mathematical models of the valve are obtained based on above definitions and rules. Some influencing factors to the valve are analyzed. The results show that the dynamic property of the valve is corresponding between simulation and test.

Key words: Dynamic property, Extra-high pressure pneumatic, Model, Pneumatic on-off valve