Yield valve for mine props in outbursts - has sealing member cone of different angle from seat cone and projecting beyond seat cone edge

摘要

The mine prop yield valve for rock bursts contains a gas-sprung piston whose cone seated sealing member works with a conical valve seat which communicates with the prop interior and has medium ports for fluid escape in emergencies. The conical sealing member surface (9, 7) has differing conicity from the valve seat (8) surface. Preferably the cone (9) on the member (7) projects beyond the edge (8') of the seat (8) cone. The sealing member and seat are of materials differing in strength and/or elasticity. A plastics ring (10) on the sealing member carries the sealing cone (7). The ring is then screwed (11) to the piston (3).