Rock burst valve with load relief valve - has dome seal seating onto pressure space base and linked via overpressure valve to pressureless space

摘要

Rock burst valve for hydraulic mine props is supplemented by a load relief valve of smaller section similarly connected to the pressure space. The base of the pressure space (5) has a port (6) of larger section than the relief valve orifice so that the conical convergent bottom end of the port acts as a seat (8) for the spherical dome of the valve seal (9). - The seal rides in a guide (10) which has side channels (11) leading to a nonpressure space (7) below the space (5). The seal has a choked (15) entry (14) to pass pressure fluid to the subseal reserve space (13) which in turn contains the spring (12) to operate the seal (9). The reserve space is connected to the non-pressure space (7) by channel (16) with an overpressure valve (17) set to a higher pressure than the load relief valve.