| 摘要 |
<p>A safety control valve system for fluid actuated devices comprising two fluid-motor operated main valve means, each of which has supply and exhaust valve members, at least one of said main valve means being normally open, that is, having its supply valve member open and its exhaust valve member closed when said valve means is de-activated. Means connects the supply valve members of the two valve means in series between supply and outlet ports and the exhaust valve members in parallel between the outlet and exhaust ports. A normally closed pilot valve is provided for the normally closed valve means, if any, and a normally open pilot valve or valves for the normally open valve means. Movement of either valve means to its exhaust position will therefore completely stop the supply of pressurized fluid to the outlet port and provide a direct exhaust connection with good exhausting capacity, even if the other valve means is stuck in an open or partially open position.</p> |
