EXHAUST PORT STRUCTURE OF BALL MILL

PURPOSE: To enable ejecting coal-water slurry containing no coarse particles from an exhaust port by connecting a conical separation material to an exit end plate at an exhaust port side of a trunk and providing a porous opening at the conical part of the separation material. CONSTITUTION: As pulverization action inside the bowl mill proceeds, grain size of coal decreases and grain size of a coal-water mixed system increases. Coal particles are not fully dispersed between a pulverization medium 16 and the coal-water mixed system and pulverization and mixing action including collision and grinding between the coal and the pulverization medium 16 is hindered and coarse particles shift in an axial direction while moving on coal- water slurry surfaces. When the particles reach the exit end plate 22, the coarse particles are hindered from moving in the axial direction and are changed in the direction to a radial direction. Further, grain size of the coarse particles is reduced by accepting pulverization and mixing action with the pulverization medium 16 moving on the conical separation material 20. The coal-water slurry containing no coarse particles passes through the porous opening of the separation material 20 and a passage 29 and is ejected from the exhaust port 18.