Classifying cyclone

Claim 1

Cyclone classifying apparatus for separating fine particles from coarser particles suspended in a gaseous medium, said apparatus comprising, a housing, an inlet which introduces a gas-particle suspension into said housing tangentially so as to form a separating vortex in which said particles move under inertial forces, and without the influence of rotating baffles, to the wall of said housing and then fall downwardly, an outlet generally located on the upper portion of said housing, for carrying away unwanted exhaust containing said fine particles from said device, means for directing classifying air in an axial direction generally upwardly toward said outlet, said means comprising a classifying air inlet and an air deflector, wherein said air deflector is shaped to direct said classifying air upwardly through an annulus formed between said air deflector and said wall of said housing, and means for redirecting particles on the wall of said housing into the path of said classifying air, said means comprising an annular deflecting ring protruding from said wall of said housing in the path of said separated particles falling along said wall, said annular ring being positioned adjacent said annulus at a location where said classifying air is travelling upwardly in a nonturbulent flow insufficient to entrain said coarser particles, and said ring having a beveled top to deflect said particles on the wall inwardly.