Valve cartridge, for lockable non-return valves for gallery lining frame struts, has main piston and control piston actuated by fluid fed through transverse channel in casing into an annular gap between it and wall of piston mounting bore

摘要

The valve cartridge, for lockable non-return valves for gallery lining frame struts in mining, has a main piston (78) and a control piston (76). This is actuated by fluid fed through a transverse channel (50) in the casing (72) into an annular gap (64) between it and the wall of the piston mounting bore (60). An independent claim is included for a valve system, use in lockable non-return valves for gallery lining frame struts in mining, containing the cartridge.