This paper proposes a new structure of valve seat which named heat shrinking assembly seat.The seat is suit for globe valves under ultra-high temperature and high pressure and other special working conditions.According to the research and development background of the valve seat red sleeve structure,structural characteristics and the determination methods for fit interference and heating temper-ature of the seat and has verified its performance through methods of Finite Element Analysis and the pressure test.
To solve the material problem of Inconel 625 bellows,the welding process of Φ25 ×0.2 tube was studied by micro-plasma,welding 0.2 mm thick strip into 25mm diameter tube.Verified the me-chanical properties of the welds of the tube welded with different process parameters by tube expansion test.The microstructure of the welding seam with different process parameters was analyzed by metal-lography.Verified the best welding process parameters of the tube through forming test of the bellows,the mechanical properties of the welds are equivalent to that of the basement,meeting the forming re-quirements of the bellows.
In order to quantitatively detect the leakage rate of the pneumatic actuator in the leakage test when lacking of professional measuring instrument.A quantitative test method of leakage test based on equation of state for ideal gas is proposed.This method uses the ideal gas state equation and the known maximum allowable leakage rate to derive the maximum allowable pressure drop of the pneumatic actu-ator in a certain holding time of the leakage test.By measuring the pressure drop before and after the leakage test,it can be judged whether the tightness of the pneumatic actuator meets the requirements of the maximum leakage rate.
In the use of the safety valve in the process of flutter and frequency jump,it is easy to affect the safety of the safety valve sealing performance and service life,more serious threat to the safety of e-quipment and personnel.Solving the problem of safety valve flutter and frequency hopping can effec-tively improve the safety and stability of safety valve operation.Based on the above,this paper analyzes the reason of the frequency jump and flutter of the safety valve,and the influence of the disc angle on the safety valve.
The pre-isolation valve is a medium self-driven built-in globe valve,using process pipe-line medium energy as the valve drive source.In order to explore the influence of the dielectric self-driven built-in structure on the flow capacity of the valve,the numerical simulation analysis of the pre-isolation valve was carried out by using fluid dynamics.The main valve stroke,disc shape and piston cylinder diameter that affect the flow capacity of the valve were determined by orthogonal analysis method,and the primary and secondary positions of each factor and the optimal structure combination of the valve were determined.Combined with the performance requirements of the valve,the influence of the built-in structure on the flow capacity of the valve is analyzed.The analysis results show that the main and secondary factors affecting the flow capacity of the valve are valve stroke,disc shape and pis-ton cylinder diameter.The flow capacity of the front isolation valve is the best when the valve stroke is 140 mm,the disc shape is concave and the piston cylinder diameter is 376 mm.The built-in structure of the drive device has little influence on the flow capacity of the pre-isolation valve.The influence of the dielectric self-drive device installed in the valve chamber on the flow characteristics of the valve can be reduced by optimizing the flow path structure(valve stroke,disc shape,piston cylinder diame-ter).
