A hydraulically operated directional control valve

摘要

In the directional control valve (10) for support mechanisms in underground mining, the valve piston (16) is guided seal free in the valve seat carrier (15) between the high pressure connection (P) and a sealing ring (22) and thus permits an overflow of high pressure fluid from the high pressure connection (P) to the return flow connection (T) on opening the valve (10). The valve (10) thus achieves an opening and closing characteristic with negative overlapping and so provides gentle switching processes, so that switching impacts with high pressure peaks do not arise.