DOWNHOLE LINEAR ACTUATION APPARATUS AND METHOD

摘要

A linear actuation apparatus for controlling fluid flow in a wellbore comprises a tubular manifold for conducting fluid through a portion thereof when disposed in the wellbore, and a shaft supported for reciprocal axial movement within the manifold. A valve seat is supported within the manifold in substantial alignment with the shaft, and a valve closure element is carried by the shaft for reciprocal axial movement therewith between a closed position preventing fluid flow across the valve seat and an opened position permitting fluid flow across the valve seat. A magnetic element is also carried by the shaft for reciprocal axial movement therewith. A pair of springs are each carried on opposing sides of the magnetic element such that one of the springs is compressed by and applies an axial force to the shaft under the movement of the shaft from a neutral position. A compound magnet is carried by the manifold about the magnetic element for applying an axial force to the magnetic element that together with the axial force of the compressed spring(s) and fluid pressure within the manifold control movement of the shaft and the valve closure element. Aspects of the apparatus define a linear actuator and a related linear actuation method.