| 摘要 |
Disclosed herein is an electro-magnetic valve actuator. The actuator includes a housing (28), a drive stem (18) extending from the housing, and an electro-magnet (14) in operable communication with the housing and drive stem, the drive stem being responsive to a magnetic field generated by the electro-magnet. Further disclosed is an electro-magnetic-mechanical valve actuator. The actuator includes a housing, a drive stem having a stem head extending from the housing, a lead screw supported by the housing a motor in driving communication with the lead screw and a follower in threaded communication with the lead screw, the follower selectively electro-magnetically affixable to the stem head. Yet further disclosed herein is a method for operating a valve actuator The method includes applying a current to an electro-magnet to urge a drive stem against a closure spring to open a valve and maintaining current in the electro-magnet to keep the valve in the open position. |
