In the normal operation of a hydraulic acrow props, the rated resistance is determined by the opening pressure of the safety valve. The higher the opening pressure of the safety valve, the higher the rated working resistance of the steel acrow props, and the higher the contact pressure requirement of the support on the top and bottom plates.
In the actual use process of the coal mine, in order to facilitate acrow prop management, the opening pressure of the safety valve was adjusted to 30T, which caused almost no safety valve to open when the working face of the broken roof was pressed periodically. When it is crushed, the roof slab will undergo wave-like flexural damage along the inclined direction; local roof fall accidents sometimes occur.
Therefore, in the daily use of safety valve opening process, management should be strengthened and rational use should be made. The opening force of the safety valve should be determined according to the stope conditions. When the roof and floor are hard and the mining height is equal to the coal thickness, the opening pressure of the safety valve should be adjusted to 30T , In order to improve the rated working resistance and topping ability of the hydraulic acrow props.
When directly jacking and the bottom plate is soft, the opening pressure of the acrow prop safety valve can be adjusted to 25T, so as to prevent the contact specific pressure of the top beam and the bottom plate from exceeding the allowable value, causing the top plate to break.
