Multi-direction after-air ports for staged combustion systems

Claim 1

A multi-directional air control device for an after-air port for passing secondary air from an opening of a windbox to an opening of a furnace, the port being of the type having a longitudinal conduit defining a chamber through which the air from the windbox passes to the furnace, the device comprising: a continuous inner shroud located inside the chamber, radially spaced from a wall of the conduit, defining a central path and an outer swirl path through the chamber and extending from the furnace opening toward the windbox opening; a plurality of outer swirl vanes disposed in the outer swirl path; a plurality of first louvers rotatably mounted within and to said continuous inner shroud about a first axis oriented perpendicular to the longitudinal axis of the conduit; a plurality of second louvers rotatably mounted within and to said continuous inner shroud about a second axis oriented perpendicular to the longitudinal axis of the conduit and perpendicular to the first louvers; and means for rotating each of the first and second louvers for controlling an air flow direction through the furnace opening.