Research On High-pressure,Super-large-flow And High-water-based Safety Valve

With the development of coal mining technology,hydraulic support equipment as one of the core equipment of fully mechanized mining technology is gradually approaching safety,efficiency,and intelligence.At the same time,the development of hydraulic supports in the direction of large mining height,advanced support and large work resistance,As a result,the overall size of the hydraulic support equipment is increased,and the requirements for the emulsion pumping station system are getting higher and higher.The high-pressure and large-flow safety valve(pressure 40 MPa,flow 1800L/min)is used in emulsion pumping stations and hydraulic supports.It is an indispensable hydraulic valve for hydraulic support and power supply equipment.It is mainly used for voltage stabilization control,overload pressure relief The role of protection is to prevent the hydraulic support or emulsion pump station from being suddenly pressurized,and unloading in time will cause damage and deformation to the entire system.Its performance will directly affect the safety factor of the emulsion pump station and the hydraulic support.Support performance.Through the analysis and research of different structures of high-pressure and large-flow safety valves in terms of working mechanism,sealing method,and valve port structure advantages and disadvantages,based on th e easy failure of sealing,long dynamic response time and nonlinear interference of hydraulic power on the spool,according to the safety valve According to the performance index requirements,the follow-up high-pressure super large flow safety valve structure is proposed,and its operation mechanism and advantages and disadvantages are analyzed while the structure optimization design is completed.The other parameter values of the safety valve are further calculated through the mathematical model of dyna mic and static characteristics.Follow-up analysis and research on dynamic characteristics and spool hydraulic power.Using AMESim to simulate the dynamic characteristics of the follow-up safety valve,the impact characteristics(flow step)and the opening and closing characteristics of the safety valve are studied in detail.The influence of different values on the pressure overshoot rate,transition process time and response time of the control spool and the main spool under the impact conditions of the safety valve damping aperture and spring stiffness is analyzed;the different positions of the orifices are compared The effect of the closed characteristic on the dynamic characteristics of the safety valve.Research shows that under the impact characteristics,the oscillation frequency of the spool decreases with the increase of the damping aperture,and the oscillation time is prolonged;the increase of the spring stiffness leads to an increase in the steady-state pressure,the spring stiffness is too small,the spool oscillates violently,and the safety valve is stable Sexual decrease.When the control spool of the safety valve is opened with a orifice,the set pressure is slightly lower than the opening of the valve sleeve,but its dynamic response performance is poor,the control spool overshoot rate is large and the transition process time is longer,so the valve sleeve is selected with Safety valve structure of orifice.Through fluid dynamic simulation calculation,the flow field simulation of different valve port structures(ordinary poppet valve structure,flange structure,follow-up structure)is carried out,and the internal pressure and velocity field of the flow field as well as the changes in hydraulic power are analyzed and targeted The effect of cavitation on the hydrodynamic force is studied.The results show that the flange structure has a good effect on the hydraulic power compensation.With the increase of the valve core opening and the inlet and outlet pressure difference,the hydraulic power value increases,and its growth rate is smaller than that of the ordinary poppet valve;the follow-up structure main spool The upper hydraulic power is similar to the ordinary poppet valve.The fluid force acting on it fluctuates around zero with the change of the opening.When the opening and the set pressure are close to the design value,the main spool receives the fluid force close to zero.The results are consistent,and the size of the set pressure can be controlled by adjusting the area of the booster chamber;the occurrence of cavitation will cause the value of the hydrodynamic force to slightly decrease,and the trend of the hydrodynamic force with the increase of opening is basically the same as that under the turbulence model.According to the simulation results of AMESim,the internal flow field of different orifice positions of the safety valve is further simulated and analyzed.The pressure and velocity cloud diagram of the internal flow field is combined with the dynamic characteristics of the simulation results to select the safety valve sleeve orifice structure.The change in the area of the pressurization chamber causes the increase or decrease of the fluid force of the main spool,which has a large impact,which proves the stable performance of the follow-up safety valve spool operation,and provides the feasibility and superior stability of the follow-up safety valve program Proved.This paper studies the dynamic and static characteristics of the proposed follow-up safety valve structure,and provides theoretical support for the feasibility of subsequent follow-up safety valve development.At the same time,the follow-up structure provides ideas and assistance for the design of hydraulic valves.