| 摘要 |
A device for a valve actuator (3) is described, the valve actuator (3) being provided with a spindle nut (4F) surrounding a portion of an actuator spindle (4A) and engaging an external threaded portion arranged on the actuator spindle (4A), the spindle nut (4F) being axially fixed relative to the actuator spindle (4A), and the actuator spindle (4A) being in rotation-preventing engagement with an end cap (3D) or an actuator housing (3A), and the spindle nut (4F) being connected via transmission means (4H, 4K, 4N, 5A, 5C) to a first driving motor (4M). The valve actuator (3) is provided with a connecting device (7B) for a second, mobile driving motor (7A), typically a torque tool from an underwater vessel. The torque tool (7A) is in engagement with the spindle nut (4F) via transmission means (4I, 4L, 7D, 7E). The actuator is provided with an actuator spring (4C) for automatically closing the valve on loss of holding current to, respectively, an electromagnetic coupling (5) connecting the spindle nut (4F) to the transmission means (4H, 4K, 4N) and a brake (6) keeping the actuator spring (4C) tightened. The actuator (3) is provided with a coupling (2) for disconnecting or connecting the actuator (3). A method of operating a valve (1) is described as well, the method including the steps of: by rotation, via an electromagnetic coupling (5), of a spindle nut (4F) which surrounds a portion of an actuator spindle (4A), is in engagement with a portion of an actuator spindle (4A) and is axially fixed relative to the actuator spindle (4A), providing an axial displacement of the actuator spindle (4A), with compression of an actuator spring (4C) via the spring plate (4E), the rotation being provided by means of at least a driving motor (4M, 7A); by providing an electromagnetic brake (6) with holding current, keeping an actuator spring (4C) tightened; by spring return, automatically closing the valve (1) on loss of holding current to, respectively, the coupling (5) and the brake (6); disconnecting an actuator spindle (4A) from a valve spindle (1I) and disconnecting an actuator housing (3A) from a valve (1B, 1C); connecting an actuator (3) by locking an actuator housing (3A) to a valve (1B, 1C) and connecting an actuator spindle (4A) to a valve spindle (1I). |
