Abstract: A material injection nozzle for a spray drying system of the type wherein the material to be dried is introduced into the exhaust pipe of one or more pulse jet engines and borne upwardly through openings in the floor of a vertical drying chamber is disclosed. The nozzle includes a substantially cylindrical member that is coaxially mounted within the pulse jet engine exhaust pipe to extend from the exit opening thereof to a point below the termination of a material feedpipe that passes coaxially upward through the lower portion of the pulse jet engine exhaust pipe. In all cases, the nozzle is dimensioned and arranged to interact with the high temperature gaseous flow and acoustic field within the exhaust pipe to eliminate or greatly reduce adherence of material passing through the exhaust pipe which would otherwise accumulate as a burned, hardened substance and cause the pulse jet engines to malfunction and cease operating.

Abstract: Spray drying apparatus is disclosed wherein circumferentially spaced apart exhaust pipes of three L-shaped pulse jet engines extend upwardly into the floor of a cylindrical drying chamber. The engines extend radially outward beneath the floor of the drying chamber, with the engine inlet openings being supported in spaced apart juxtaposition with air augmentation ducts which extend upwardly and tangentially into the drying chamber at equally spaced apart positions near the drying chamber floor. Moisture laden material, such as a slurry tht contains the material to be dried is introduced into the upwardly directed exhaust stream of each engine by means of feedpipes which pass coaxially along the interior of each engine exhaust pipe and an injection nozzle that is affixed to the terminus of each feedpipe at a predetermined distance below the engine exhaust opening.