Abstract: An electrically operated valve actuator effective for shifting a valve (10) between open and closed positions is disclosed, the valve actuator comprising a movable member in the form of a valve stem (21) connected to a valve body (14), the movable member being driven by an electric motor (22) in linear motion between valve closing and valve opening positions, wherein electrical power to the motor is supplied via a current (25) control including a supplied current detection device. The movable member is designed for an idling length of travel (L) in the opening and closing directions during which the valve (10) is either fully open or fully closed, and the movable member is associated with buffer means (30) that during the idling length of travel gradually increases the torque and power required to move the movable member further in the open and closed positions of the valve (10), respectively.

Abstract: A sub sea valve actuator system including a piston and cylinder assembly and a return spring arranged in an actuator housing, a hydraulic pump and electric motor assembly associated with the piston and cylinder assembly, and hydraulic flow lines for hydraulic medium driving the piston and cylinder in relative displacement against a force of the return spring. The valve actuator system includes a detector configured to detect an end-of-stroke position of the piston and cylinder assembly. The detector includes at least one of: a motor current monitoring circuit unit, a hydraulic medium pressure sensor unit, a position sensor unit, and a linear variable differential transformer unit. An electromechanical arresting mechanism is arranged to be energized for releasably arresting the return spring in a compressed state in result of the detected end-of-stroke position.

Abstract: A gate valve actuator including a stem that is movable linearly in an actuator housing connectable to the gate valve. The stem acts on the gate valve to shift the gate valve between open and closed positions, respectively. The stem is driven by a motor in a first direction into a steady state operation position. In the position the stem is biased in a second opposite direction towards a shutdown position by a spring member acting on the stem. A trigger mechanism is arranged for holding the spring member in a compressed state. The trigger mechanism includes an electrically controllable trigger that is arranged for release of the spring member in result of de-energizing the electrically controlled trigger. A method for shifting a gate valve between a steady state operation mode and a shutdown mode utilizing the gate valve actuator.

Abstract: A subsea valve actuator is disclosed, comprising an override shaft (6) reaching from inside a fluid filled and pressure compensated actuator housing (1) to the exterior thereof via a bearing and sealing arrangement (7), wherein a visual valve position indicator (14) is arranged exterior to the actuator housing. The visual indicator (14) is pivotally mounted to the override shaft and guided non-rotatably to be forced in axial displacement on the override shaft when the override shaft is rotated, wherein the mounting of the visual indicator (14) on the override shaft (6) is encased in a fluid filled, pressure compensated indicator mounting enclosure (19) surrounding the override shaft (6) in sealing (26) relation outside of the actuator housing (1).

Abstract: A subsea arrangement comprising an external casing and a pressure equalizing valve for equalization of the fluid pressure in an internal space of the casing. The pressure equalizing valve is provided with a valve body including a base section displaceably received in an opening provided in the casing; and a valve member secured to the base section and arranged inside the casing, the valve member facing a valve seat surrounding said opening. The valve body is displaceable upwards, under the effect of an external fluid pressure, from a resting position, in which the valve member prevents fluid flow into and out of said internal space, to a raised position, in which the valve member allows fluid flow from the surroundings into said internal space for equalization of the fluid pressure therein when the subsea arrangement is lowered into the sea.

Abstract: A sub sea valve actuator system including a piston and cylinder assembly and a return spring arranged in an actuator housing, a hydraulic pump and electric motor assembly associated with the piston and cylinder assembly, and hydraulic flow lines for hydraulic medium driving the piston and cylinder in relative displacement against a force of the return spring. The valve actuator system includes a detector configured to detect an end-of-stroke position of the piston and cylinder assembly. The detector includes at least one of: a motor current monitoring circuit unit, a hydraulic medium pressure sensor unit, a position sensor unit, and a linear variable differential transformer unit. An electromechanical arresting mechanism is arranged to be energized for releasably arresting the return spring in a compressed state in result of the detected end-of-stroke position.

Abstract: A gate valve actuator including a stem that is movable linearly in an actuator housing connectable to the gate valve. The stem acts on the gate valve to shift the gate valve between open and closed positions, respectively. The stem is driven by a motor in a first direction into a steady state operation position. In the position the stem is biased in a second opposite direction towards a shutdown position by a spring member acting on the stem. A trigger mechanism is arranged for holding the spring member in a compressed state. The trigger mechanism includes an electrically controllable trigger that is arranged for release of the spring member in result of de-energizing the electrically controlled trigger. A method for shifting a gate valve between a steady state operation mode and a shutdown mode utilizing the gate valve actuator.