Abstract: The valve actuator (10) has a movable control element (12) which is typically connected to the valve to be opened/closed and a propulsion device (16) which may be a hydraulically operated piston (16) for moving the movable control element. A resilient element (22) which may be in the form of a spring arrangement has a stroke extending from a first relatively unloaded position to a second relatively loaded position and a transmission mechanism (18) is also provided, where the resilient element is loaded under the action of the propulsion device via the transmission mechanism and is configured to urge the moveable portion of the propulsion device towards the first position via the transmission mechanism when loaded. The transmission mechanism provides a gearing ratio reduction between the moveable portion of the propulsion device and the resilient element.

Abstract: A deployment device is described which comprises a support frame 12 provided with buoyancy tanks 20, the buoyancy of which is adjustable, the support frame 12 being adapted for use in carrying and/or deployment of a payload.

Abstract: A valve seat (10) for use in a valve incorporating a valve gate is disclosed, the valve seat comprising a valve seat body (12) and a biasing device (14) such as a spring (14), the biasing device being integral with the valve seat body. The biasing device and valve seat body may be welded together or may be formed in a single metal workpiece by a machining, casting or forging process. The valve gate and valve seat cooperate to form a metal-to-metal seal within the valve. At least a portion (15) of the valve seat is typically welded to at least a portion of the valve. A pipeline including at least one valve is also disclosed, as is a method of fitting a valve seat to a valve.

Abstract: The valve actuator (10) has a movable control element (12) which is typically connected to the valve to be opened/closed and a propulsion device (16) which may be a hydraulically operated piston (16) for moving the movable control element. A resilient element (22) which may be in the form of a spring arrangement has a stroke extending from a first relatively unloaded position to a second relatively loaded position and a transmission mechanism (18) is also provided, where the resilient element is loaded under the action of the propulsion device via the transmission mechanism and is configured to urge the moveable portion of the propulsion device towards the first position via the transmission mechanism when loaded. The transmission mechanism provides a gearing ratio reduction between the moveable portion of the propulsion device and the resilient element.