Pressure-relief valve for hydraulic support systems, in particular for use as a rock-burst valve

摘要

The invention relates to a pressure-relief valve for hydraulic support systems which is preferably used as a rock-burst valve. The closing body (8) of the valve is partly pressure-compensated with the use of a compensating piston (10); it is loaded on the one hand in the opening direction by the hydraulic pressure at the valve inlet (6) and on the other hand in the closing direction from the rear side via the compensating piston (10), the pressure-compensation space (17) which accommodates the compensating piston (10) being connected to the valve inlet side (6) via an axial connecting passage (25). According to the invention, a stop valve (24) controlled by the hydraulic system pressure (prop pressure) is allocated to the pressure-compensation space (17). In the event of an overload, the stop valve (24) suddenly relieves the pressure-compensation space (17) so that the closing body (8) lifts from its valve seat (7) and opens the discharge of the pressure fluid towards the valve outlet (9). As soon as the pressure in the hydraulic system (prop pressure space) has fallen again to a preset value, the hydraulically releasable valve (24) closes again so that the pressure at the valve inlet side can build up again in the pressure-compensation space, which pressure puts the pressure-relief valve into the closed position. IMAGE