Volume reducer for powder material

摘要

A volume reducer for reducing the volume of a powder material by removal of some air has a cylindrical casing having an inlet and an outlet for letting powder material in and out. In the casing, a rotor rotatable on the center axis of the casing is provided. The rotor has a cylindrically formed porous plate and a plurality of inner and outer chambers formed in the inside and outside of the porous plate. The outer chambers are loaded with the powder material. A rotary valve that rotates together with the rotor is provided. The rotary valve has a plurality of ventilation openings communicating with the respective inner chambers in an axial direction. The rotary valve is embraced in a stationary valve. The stationary valve has a cavity that communicates with a ventilation opening when the rotary valve is positioned within a predetermined range of its rotation angle. The stationary valve has a compressed air injection opening with which the ventilation opening communicates.