The powder classifying device

The powder classifying device classifies powder having a particle size distribution and collects the classified powder. The device includes a disc-like cavity (16) to which the powder is supplied and where the supplied powder is classified, a powder supply port (18) for supplying the powder to the cavity, guide vanes (40) arranged so as to extend from an outer periphery of the cavity in an inner direction at a predetermined angle, a discharge unit (22) for air streams including fine particles discharged from the cavity, a collection unit (30) for coarse particles discharged from the cavity and air nozzles arranged below the guide vanes on an outer peripheral wall of the cavity along a tangential direction of the outer peripheral wall and blow compressed air into an inside of the cavity.