Research and application of controllable, agile, and pressure-stabilizing liquid supply system for coal mining face

During group advancing of hydraulic supports at a coal mining face, the hydraulic system experiences excessive pressure fluctuations, and the maximum capacity of the liquid supply system cannot meet instantaneous high-flow demand. Pressure-stabilizing liquid supply with support-mounted accumulators is also subject to delayed startup and competition for liquid. To address these problems, the accumulators were installed on the mining equipment train, and a controllable, agile, and pressure-stabilizing liquid supply system based on an accumulator station was designed. A simulation model of the working-face hydraulic system was established to analyze pressure and flow fluctuations at the support inlet during group advancing. The analysis showed that when the support-advancing time met working-face requirements, the support-inlet pressure fluctuated sharply and the pump station incurred additional overflow losses. By controlling the connection and disconnection between the accumulator-station outlet and the main supply line of the hydraulic system, the system provided rapid liquid replenishment at low pressure and rapid pressurization of support legs, thereby enabling real-time matching between liquid-supply capacity and demand as well as agile dynamic liquid replenishment. Simulation results showed that after deployment of the system, the time required for advancing the scraper conveyor and hydraulic supports decreased by 26.0%, and pressure fluctuations decreased by 45.3%. Industrial tests showed that after deployment, the system achieved a marked pressure-stabilizing effect: pressure fluctuations decreased by 66.0%, and pressure was concentrated in the high-pressure range, which was more conducive to the stable and rapid operation of working-face hydraulic equipment.