Image Number 5 for United States Patent #7234489.
A valve assembly (10) comprises a vortex chamber (14) with an axial outlet port (20), a main inlet port (16) for a fluid to be controlled, and a substantially tangential inlet port (25); the fluid enters through an inlet chamber (13) in which is a mechanical valve (26) movable so as to obstruct fluid flow into the vortex chamber (14). A duct (24) links the inlet chamber (13) to the tangential inlet port (25) of the vortex chamber. The position of the mechanical valve (26) affects the flow of fluid through the duct (24), so the vortex chamber (14) amplifies the effect of the mechanical valve. Further movement of the valve (26) closes off flow altogether (40). The assembly may include a weir (36) in the outlet, to separate gas and liquid phases.