Method of Operation

With the PALLMANN double stream mill the feed material is reduced through a new, pioneering principle. The fan effect of a multiple wing impeller pulls the feed material centrally into the grinding chamber passing through a special feed chute designed as a gravity separator for heavy material. An especially designed material guiding cone distributes the material evenly on the periphery and the entire width of the grinding track. The impeller, rotating at high speed, produces high air turbulence between the impeller wear plates and the serrated profile of the grinding track.

The double stream guides the feed material through this intensive turbulence in axial direction or in the cross stream depending on the profile used on the grinding track. The material is reduced in high velocity air stream by repeated impact onto the impeller wear plates and the grinding track profile. Through the air guide and within the flow channels of the grinding track a cross-stream sifting is achieved. Discharging of finished product takes place only after the dragging force of air exceeds the kinetic rebound energy applied to the particles. In the area of this actual flow the percentage of mechanical friction is extremely small resulting in an extended service life of impeller wear plates and refining elements.