| 摘要 |
<p>Manual overrides for valves are disclosed herein. An example apparatus includes an actuator (102) to move a stem (18) of a valve. The actuator includes a housing (126,150) defining a bore (128) and a piston (132) disposed in the bore. The example apparatus also includes a rod (170) movably coupled to the housing to extend into the bore, and the piston is to be movable via the rod or a fluid to flow into the bore. The example apparatus also includes a lock (188) to hold the rod in a first position on the housing where the rod is to disable a supply of the fluid to the bore.</p> |
