High volume ceiling type air diffuser

An air diffuser for directing air through a single elongated opening in a drop ceiling in a pattern directed along the plane of the ceiling, comprising:

• a plenum chamber positioned above the plane of the ceiling having a bottom wall extending parallel to the plane of the ceiling and having side walls extending upwardly from the bottom wall, a pair of spaced parallel vertical walls extending downwardly from the bottom wall of the plenum chamber above the elongated opening in the ceiling, said parallel walls extending parallel to the length of the elongated opening and being spaced apart a distance greater than the width of the opening, the bottom wall of the plenum chamber being open between the parallel walls for passing air from the plenum chamber into the space between the parallel walls out the opening in the ceiling, the lower edge of at least a first one of the parallel walls terminating in a ledge extending perpendicularly toward the opposite parallel wall, a first baffle positioned in the plenum chamber and extending into the space between the parallel walls toward the ledge, the first baffle forming a first throat with said first one of the parallel walls for discharging air in a first stream directed downwardly from the plenum chamber at said ledge, and a second baffle positioned in the plenum chamber above the opening between the parallel walls, the first and second baffles intersecting within the plenum chamber the second baffle forming a second throat with the bottom wall of the plenum chamber for discharging air from the plenum chamber in a second stream directed at said first baffle and associated ledge.