Research On Hydraulic Support Composite Safety Valve

As an important safety control Component of the hydraulic support,the safety valve of the hydraulic support pillar is mainly used to protect the hydraulic support pillar (cylinder) and its stmctural members from overload by overflow.The working characteostics of safety valve,namely pressue overshoot and response time,have a signincant impact on the reliability of hydraulic support when the roof of working face is impacted by pressure.Therefore,the research on the dynamic charactcostics of safety valve has certain academic value,and the improvement and developmcnt of high-performance safety valve products have good practical application value.Taking a certain type of mine hydraulic support pillar safety valve as the physical object,this paper introduces the stmcturc and working principle of thc safety valve based on its working conditions and working status.Through the dynamic analysis of the safety valve spool and the hydrodynamic analysis of the throttle hole,the dynamic mathematical model of the relief valve overflow process is established.The soawarc MATLAB/simulink is used to carry out the simulation experirncnt of various comnbined structtrcs.By analyzing and comparing the dynamic characteristics of single large now safety valve and multi-small flow combincd safety valve,it is concluded that when the roof beam of hydraulic support meets the impactload of coal seam root,under the same total flow area,the small now combined safety valve can enhance the impact resistance of the hydraulic suppont pillar and reduce the overshoot of the liquid pressure in the hydraulic suppon pillar and the dynamic charactenstics of the system are obviously improved.The theory of PID control is applied to safety valve.Hydraulic cylinder is used as proportional part of PID control,accllmulator is used as integral part of PID control and direct-acting safety valve is combined to form a combined safety valve based on the concept of PID.The results show that the combined safety valve system improves the dynamic characteristics of liquid pressure in the pillar of mining hydraulic support,improves the stability of the system and enhances the reliability of the system.Based on this innovativcconcept,a new type of combined safety valve product can be developed.