Abstract: A rotary actuator comprises a unitary housing having a cavity therein and defining a continuous internal sealing surface. A rotary piston is located within the cavity in sealing engagement with the sealing surface of the cavity such that the rotary piston divides the cavity into isolated first and second chambers, wherein the rotary piston is arranged to rotate about a rotation axis in accordance with a pressure differential applied between the first and second chambers.

Abstract: A valve apparatus comprises a housing defining a flowpath extending between a valve inlet and a valve outlet and an access port formed in a wall of the housing separately from the valve inlet and the valve outlet to provide access to the flowpath at a location which is intermediate the valve inlet and valve outlet. A valve mechanism is mounted within the flowpath, wherein the valve mechanism in insertable through the access port.

Abstract: A first cutter is provided on an edge region of a first surface of a gate valve member to be moveable across the flow path with the gate valve member along a first cutting plane. A first seal pocket is defined by a depression in the first surface of the gate valve, wherein a second peripheral seal surface is provided within the first seal pocket. The first valve seat and the gate valve member are axially moveable relative to each other to permit a portion of the first valve seat to become received into the first seal pocket of the gate valve member when said gate valve member is located within its second position to provide sealing engagement between the first and second peripheral seal surfaces.

Abstract: A rotary actuator comprises a unitary housing having a cavity therein and defining a continuous internal sealing surface. A rotary piston is located within the cavity in sealing engagement with the sealing surface of the cavity such that the rotary piston divides the cavity into isolated first and second chambers, wherein the rotary piston is arranged to rotate about a rotation axis in accordance with a pressure differential applied between the first and second chambers.

Abstract: A subsea test tree comprises a housing defining a flow path, a valve member mounted in the housing and an actuator coupled to the housing. A drive arrangement extends through a wall of the housing to operatively connect the actuator to the valve. The actuator is operable to operate the valve member to control fluid flow along the fluid pathway. Also disclosed are improvements to actuators.

Abstract: A first cutter is provided on an edge region of a first surface of a gate valve member to be moveable across the flow path with the gate valve member along a first cutting plane. A first seal pocket is defined by a depression in the first surface of the gate valve, wherein a second peripheral seal surface is provided within the first seal pocket. The first valve seat and the gate valve member are axially moveable relative to each other to permit a portion of the first valve seat to become received into the first seal pocket of the gate valve member when said gate valve member is located within its second position to provide sealing engagement between the first and second peripheral seal surfaces.

Abstract: A rotary actuator comprises a rotatable vane assembly mounted within a housing to define first and second chambers, wherein the rotatable vane assembly is rotatable between first and second positions. A first fluid port is in communication with the first chamber to permit an actuation fluid to be delivered to/from the first chamber, and a second fluid port is in communication with the second fluid chamber to permit actuation fluid to be delivered to/from the second fluid chamber. A sealing arrangement is provided for sealing at least one of the first and second fluid ports when the vane assembly is located in one or both of its first and second positions.

Abstract: A valve apparatus (10) comprises a housing (12) defining a flow path (14), a valve seat (42) located within the housing (12) around a periphery of the flow path (14), a carriage member (16) located within the housing (12), a cutting arrangement (28) mounted on the carriage member (16), and a valve member (32) mounted on the carriage member (16) via a connection assembly (34) which permits relative movement between the valve member (32) and the carriage member (16). The carriage member (16) is moveable from a first position towards a second position to drive the cutting arrangement (28) across the flow path (14) and to move the valve member (32) into a position in which relative movement between the valve member (32) and the carriage member (16) permits the valve member (32) to sealingly engage and disengage the valve seat (42) to control flow along the flow path (14).