The working process of a single hydraulic prop consists of four stages: ascending column, preliminary support, carrier, and returning column:
(1) At the stage of lifting the single hydraulic prop, insert the injection gun into the three-purpose valve, and pass the working pressure of the emulsion pump station (15-20MPa) to remove the working medium (including M10 emulsifier 1%-2% emulsion) Inject into the column cavity.
(2) In the preliminary support stage of the hydraulic acrow props, after the lifting support surface on the movable H-pillar is expanded, pull out the injection gun. At this time, the working pressure of the inner cavity of the hydraulic prop is equal to the working pressure of the pump station, and the supporting force given by the prop to the supporting working surface is called the initial supporting force.
(3) In the carrier stage, with the operating time, the load of the hydraulic prop on the cover of the prop increases. When the load on the hydraulic prop is lower than the working resistance, the safety valve is closed to restore the balance of the prop. When the load on the prop When the rated working resistance is exceeded, the safety valve in the three-way valve is opened, the liquid in the cavity overflows, the pressure in the cavity decreases, and the living column shrinks.
(4) In the stage of returning the hydraulic acrow props to the column, the three valve unloading valves are opened, and the working fluid of one inner cavity prop is discharged to the goaf area of the unloading valve and will not be collected. The movable column retracts under its own weight to achieve the purpose of reducing the hydraulic prop, and the column moves forward in this way.
