Patent attributes
A linear actuation apparatus for controlling fluid flow comprises a tubular manifold for conducting fluid through a portion, 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 between a closed and an opened position. A magnetic element is also carried by the shaft for reciprocal axial movement therewith. A pair of springs are carried on opposing sides of the magnetic element wherein one spring is compressed and applies an axial force to the shaft when the shaft is moved from a neutral position. A compound magnet, carried by the manifold, applies an axial force to the magnetic element that together with the axial force of the spring(s) and fluid pressure control movement of the shaft and the valve closure.