Fine grinding roller mill

Abstract

A roller mill for pulverizing material and separating the pulverized material has a mill for crushing the material and a classifier disposed on the mill for separating the crushed material. The mill includes a grinding mechanism that has a plurality of grinding rolls and a grinding ring that coact to pulverize material within a mill housing, which defines a grinding chamber. The classifier is a centrifugal-type classifier having a motor-driven rotor disposed within a classifier housing, which define a classifying chamber. The rotor has a plurality of blades that extend outwardly from the rotor. As the rotor rotates within the classifying chamber, the blades separate fine sized particles from oversized particles by passing the finer sized particles through the blades, and contacting and propelling the oversized particles against the classifier housing. The oversize particles fall downward through an outer annular passage defined by a baffle and the mill housing back to the grinding mechanism. The baffle is disposed along the inner periphery of the mill housing spaced at a distance from the mill housing to provide an inner passage and an outer annular passage. The inner passage directs particle-laden air upward through the grinding chamber to the classifier. The goat annular passage receives and directs the oversized particles downward to the grinding mechanism of the mill through an opening at the bottom of the outer annular passage for directing the oversized particles to the grinding mechanism.