Patent attributes
A hybrid turbine classifier for a coal pulverizer includes a cone disposed within the separator body of the pulverizer. The cone extends downwardly from a base to a frustum which forms an opening for depositing coal particles on the grinding table of the pulverizer. The outer surface of the cone and the separator body define an outer passage for coal/air flow, containing a mixture of smaller and larger coal particles, from the grinding table. A circular, first classifier cage disposed proximate to the base of the cone defines a circumferential passage between the outer passage and the cavity of the cone. The first classifier cage includes static, circumferentially-spaced vanes which direct the coal/air flow in a spiraling, circular flow path within the cavity. The flow path defines a first flow direction. A circular, second classifier cage is coaxially disposed within the first classifier cage. The second classifier cage includes a rotor which is rotatable around the axis and which defines a circumferential outlet from the cavity. The rotor has circumferentially-spaced blades directing the coal/air flow in a second flow direction opposite to the first flow direction. The vanes of the first classifier cage define a static vane angle selected to direct the coal/air flow tangentially to the blades of the second classifier cage.
