| 摘要 |
<p>An assembly of control valves in which each valve has a piston sliding in the bore of a housing to traverse a neutral position and two control positions; the piston has a flow path therethrough and this flow path is combined with additional ducts or recesses in the piston so that in the neutral position as well as in both control positions the piston provides a through-flow between fluid return connections communicating with the bore.</p> |
