By analyzing the construction and working principle of quick closing valves of feed water pump s driving steam turbine,the necessity and feasibility of the quick closing valve s reconstruction is being elucidated,accompanied by a repor.

The accident phenomenon and its course,analysis and prevention measures are expounded on the quick closing valve of the feed pump turbine which causes the failure in online test.

This impulsion tool uses a high speed on-off valve to control to-and-fro motion of the distributing oil valve core, which impels the cylinder rod to-and-fro motion to form impulsion.

The dissertation analyzes several different hydraulic controlling valves, mainly high speed on-off valves.

Simulation and experimental investigation on pressure dynamics of pneumatic high-speed on/off valves;

Electronically assisted braking system for vehicles based on a high-speed on/off valve;

The Research on the Electro-hydraulic Control System with High-speed ON/OFF Valve;

Research and application of a new PWM high speed on/off valve;

According to the slow response of electro-hydraulic actuator driven by single high speed on/off valve,which was leaded by the restrained volume of high speed on-off valve,the solution that using a high speed on-off valve as the pilot valve and a secondary valve as the distributing valve was presented.

High speed on/off valve is an excellent conversion element which has been developed since 1980 s, it has many merits such as high response speed , good ability of resisting contaminated oil and capability of assorting well with electro circuit.

The calculation domain includes the entire flow fields in the head portion,mainly involving the main steam quick-closing valve,regulating valves and stages.