Patent ID: 7588205

Claim:
A medium agitation mill in which an agitating member is rotatably fixed in a cylindrical pulverizing tank with an inlet provided for a raw material bearing a substance to be pulverized, the pulverizing tank having a pulverizing compartment with a pulverizing medium contained therein, thus rotating the agitating member while being supplied with the raw material via the inlet and agitating the pulverizing medium to crush or grind the substance into ultrafine particles, characterized in that: the agitating member comprises a hollow, bottomless cylinder having a cylindrical wall on its circumference, the cylindrical wall having apertures circumferentially made at intervals for circulating the pulverizing medium; the agitating member has a medium-separating vane wheel arranged coaxial with the agitating member and fixed in its inner space and, the medium-separating vane wheel having a plurality of vanes arranged on its circumference and fixed at intervals; and a hollow drive shaft has an outlet at its end, opening to the inside of the medium-separating vane wheel, and is adapted to drive and rotate the vane wheel so as to make the relatively heavy medium fly away from the relatively light “to be pulverized” substance in radial directions under the centrifugal influence, allowing the crushed substance separate from the medium to flow into the outlet, which has an on-off valve responsive to the standstill of the vane wheel for closing the outlet and responsive to the rotating of the vane wheel for opening the outlet under the centrifugal influence.