Electrical servo drive for valve - has movable wall bounding chamber acted upon by spring and pressure medium

摘要

The electrical servo drive is for axial adjustment of the setting element of a valve etc. It has a housing which is rigidly connected with the valve and a motor driven movement thread which can be coupled with the setting element. There is also a device containing a spring for automatically returning the setting element into an end position on failure of the motor drive. A section (9) of the movement thread (10) is coupled with a movable wall (14) which bounds a chamber (20) in the housing (1), which on one side is under the cutter of a spring (19). The chamber (20) is connected with a pressure medium supply (21) via an electrically operated control valve (23). The pressure medium cuts on the other side of the movable wall.