Hydraulic circuit for longwall support

摘要

The invention relates to a hydraulic circuit for the longwall support in underground mining for supporting a longwall by means of a plurality of support shields, which hydraulic circuit comprises a pressure sensor (19) in the annular piston line (10) of each cylinder/piston unit (4). When a predetermined maximum pressure is reached, the pressure sensor (19) emits a pressure warning signal (28), by which the entire longwall can be depressurized by means of a longwall cut-off valve (11). The pressure warning signal (28) is locked with respect to any control signal for one of the hydraulic valves.