COAL BASED THERMAL POWER PLANTS: COAL MILLS
In this type, leakage in the mill area is the suction type, the exhauster is used for lifting the milled coal from the pulverizer to the furnace through a cyclone. The tube mills have a large circular drum, with adequate ball charge, which is rotated at about 70% of the speed at which the ball charge would be held against the inner surface by centrifugal force.