Abstract: An air sieving apparatus capable of sieving particles in a particle size range below 50 ?m includes a cylindrical screening case defining an internal space and provided with a screen dividing the internal space into an upper space and a lower space. Powdered material is fed through a powdered material feed opening onto a bottom plate disposed to cover the lower open end of the screening case with gaps formed therebetween. Air in the screening case is sucked upward by a suction blower. The fed powdered material is dispersed by currents of air sucked through the gaps and the dispersed powdered material is sucked upward. Fine particles that have passed through the screen 3 flow through a fine particle recovery duct into a cyclone and a fine particle container. Coarse particles remaining in the lower space drop through the coarse particle recovery opening into a coarse particle container.

Abstract: An air sieving apparatus capable of sieving particles in a particle size range below 50 ?m includes a cylindrical screening case defining an internal space and provided with a screen dividing the internal space into an upper space and a lower space. Powdered material is fed through a powdered material feed opening onto a bottom plate disposed to cover the lower open end of the screening case with gaps formed therebetween. Air in the screening case is sucked upward by a suction blower. The fed powdered material is dispersed by currents of air sucked through the gaps and the dispersed powdered material is sucked upward. Fine particles that have passed through the screen 3 flow through a fine particle recovery duct into a cyclone and a fine particle container. Coarse particles remaining in the lower space drop through the coarse particle recovery opening into a coarse particle container.

Abstract: A particle feed apparatus is combined with a jet mill and has a particle feeder for feeding particles to an air injector that injects particles together with particle carrying air into the jet mill. The particle feed apparatus is a closed structure isolated from the environment. The use of the closed particle feed apparatus prevents the backflow of dust-loaded air that occurs in a milling system formed by combining a jet mill and an open particle feed apparatus. The use of the closed particle feed apparatus improves the working environment, enhances the milling ability of the jet mill and facilitates operations.