Gong-kuang zidonghua (Nov 2021)
Study on the fast fluid supply and return scheme of hydraulic support column in fully mechanized working face
Abstract
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 935 s and is 221% shorter than the traditional scheme. Therefore, it is concluded that the direct supply scheme by electro-hydraulic controlled reversing valve is the best scheme.
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