综采工作面液压支架立柱快速供回液方案研究

Study on the fast fluid supply and return scheme of hydraulic support column in fully mechanized working face

液压支架自动跟机控制应具备高支护、快速移架、大推移距离等性能,其中在保障采场安全的前提下,缩短工作面空顶时间是一个极为关键的问题。但目前液压支架自动跟机控制存在动作时间长、较手动操作效率低、控制参数凭经验设定等问题,导致综采工作面推移速度慢、液压系统压力与流量匹配不佳等问题。为减少液压支架动作时间,提高综采工作面推移速度,建立了液压支架阀控缸单元液压缸伸出动作瞬态过程的流量-压力数学模型,分析认为液压缸伸缩瞬间压力主要与供回液压力有关,且与时间呈二次方关系。基于上述结论,提出了立柱供液阀直供、二级控制+立柱快速供液阀、电液控换向阀直供3种立柱快速供回液方案,详细介绍了3种方案的工作原理。在AMESim软件中建立了基于3种方案的液压支架仿真模型,通过分析不同方案下液压支架在执行降柱-移架-升柱循环动作时液压缸无杆腔、有杆腔瞬态压力及动作时间,对比了3种方案的稳定性和快速性,结果表明:3种方案下液压支架执行降柱-移架-升柱循环动作时液压缸无杆腔、有杆腔压力曲线变化趋势基本一致,认为3种方案的稳定性基本相同;电液控换向阀直供方案下液压支架执行降柱-移架-升柱循环动作的总时间最短,为9.35 s,较传统方案缩短22.1%,因此得出电液控换向阀直供方案为最佳方案。

The hydraulic support automatic follow-up control should have the performance of high support,fast support moving,large moving distance,etc.Among these performance,under the premise of ensuring stope safety,shortening the time of working face empty roof is an extremely critical issue.However,the current hydraulic support automatic follow-up control has problems such as long action time,lower efficiency than manual operation,control parameters set by experience and other problems,resulting in the slow moving speed of the fully mechanized working face,and poor matching of hydraulic system pressure and flow.In order to reduce the action time of the hydraulic support and improve the moving speed of the fully mechanized working face,the flow-pressure mathematical model of the hydraulic support valve-controlled cylinder unit in hydraulic cylinder extension action transient process is established.The analysis shows that the instantaneous pressure of the hydraulic cylinder extension is mainly related to the supply and return hydraulic pressure,and has a quadratic relationship with time.Based on the above conclusions,three schemes for column fast fluid supply and return named direct supply by column liquid supply valve,two-level control+column fast liquid supply valve,and direct supply by electro-hydraulic controlled reversing valve are presented.The working principles of the three schemes are introduced in detail.The simulation models of hydraulic support based on the three schemes are established in AMESim software,and the stability and rapidity of the three schemes are compared by analyzing the transient pressure and action time of the rod cavity and rodless cavity of hydraulic cylinder when the hydraulic support executes the cycle of column lowering-support moving-column lifting under different schemes.The results show that the pressure curves of the rod cavity and rodless cavity of hydraulic cylinder are basically the same when the hydraulic support executes the cycle of column lowering-support moving-column lifting under the three schemes.It is considered that the stability of the three schemes is basically the same.The total time for the hydraulic support to perform the cycle of column lowering-support moving-column lifting under the direct supply by electro-hydraulic controlled reversing valve is the shortest,which is 9.35 s and is 22.1%shorter than the traditional scheme.Therefore,it is concluded that the direct supply scheme by electro-hydraulic controlled reversing valve is the best scheme.