Patent ID: 7472680

Claim:
A vortex generator for flow of a fluid comprising: a housing that includes a passage through which the fluid flows; and a valve that is movably coupled to the housing between a fully closed position and a fully open position for changing flow of the fluid in the passage, wherein the valve includes an open portion that defines a main aperture for generating a vortex in the flow of the fluid, wherein the valve also has an intermediate position between the fully closed position and the fully open position, wherein: the housing further includes a recessed portion such that the recessed portion of the housing and the valve cooperate to define a sub-aperture through which the fluid flows when the valve is positioned in the intermediate position, and the passage includes an entrance through which the fluid enters the passage and an exit through which the fluid exits the passage, wherein the housing includes a first recessed portion that extends from the entrance to an area adjacent the valve when the valve is in the fully closed position, and wherein the housing includes a second recessed portion that extends from the exit to an area adjacent the valve when the valve is in the fully closed position.