Device for a spring return valve actuator and method of operating a valve
AssigneeElectrical Subsea & Drilling AS
InventorEgil Eriksen
Life of this patent
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Abstract
A device for a valve actuator is described, the valve actuator being provided with a spindle nut surrounding a portion of an actuator spindle and engaging an external threaded portion arranged on the actuator spindle, the spindle nut being axially fixed relative to the actuator spindle, and the actuator spindle being in rotation-preventing engagement with an end cap or an actuator housing, and the spindle nut being connected via transmission means to a first driving motor.
Claims10
A device for an electromechanical valve actuator, characterized in that:
- the valve actuator is provided with a spindle nut surrounding a portion of an actuator spindle and being in engagement with an external threaded portion arranged on the actuator spindle, the spindle nut being axially fixed relative to the actuator spindle;
- the actuator spindle is in rotation-preventing engagement with an end cap or an actuator housing;
- the spindle nut is connected via transmission means to a driving motor;
- the spindle nut is provided with an electromagnetic coupling which is in permanent engagement with the transmission means of the driving motor and in engagement with the spindle nut via electromagnetic engagement;
- and
- the spindle nut is provided with an electromagnetic brake which is mounted on an actuator attachment and is in rotation-preventing engagement with the spindle nut via electromagnetic engagement;
- and
- the actuator spindle is connected to an actuator spring which is arranged to be compressed by the axial displacement of the actuator spindle, the actuator spindle being subjected to a push force in the opposite direction to, via the brake and the coupling, release the spindle nut for rotation;
- and
- the valve actuator is provided with a coupling for disconnecting the actuator spindle from a valve spindle, which is attached to the valve slide, and a coupling for releasing the actuator housing from the valve.
A method of operating a valve by means of a valve actuator, characterized in that the method includes the steps of:
- by the rotation of a spindle nut which surrounds a portion of an actuator spindle, is in engagement with an external threaded portion arranged on the actuator spindle and is axially fixed relative to the actuator spindle, providing an axial displacement of the actuator spindle, with compression of an actuator spring via the actuator spindle and a spring plate, the rotation being provided by means of at least one driving motor;
- keeping the spindle nut connected to the transmission means by providing a coupling with holding current;
- keeping an actuator spring tightened by providing a brake with holding current;
- closing the valve automatically by spring return on loss of holding current to the coupling or brake;
- releasing the valve actuator from the valve by disconnecting the actuator spindle from a valve spindle and disconnecting an actuator housing from a valve housing;
- and
- connecting the valve actuator to the valve by locking the actuator housing to the valve housing and connecting the actuator spindle to the valve spindle.
Dependencies are inferred from the claim text.