| 摘要 |
<p>The non-return valve for use in hydraulic supports in deep coal mining comprises a casing (2) with several connection ports (3 - 5) in which a control piston (6) and valve piston (10) are mounted. The valve piston can slide in a sleeve (18) mounted in a bore (8) in the casing against the force of a valve spring (12). The sleeve is filled with water and only allows a controlled connection of the bore (8) with an inner chamber (19).</p> |
