Pulverizers are equipments that reduce the coal to the required fineness before entering the boiler furnace. Pulverizering units are of two types "impact mill″ and "ball mill″. The impact mill hammers coal into fine particles by means of hammers mounted on a rotating shaft. In ball mill the coal is crushed by heavy steel balls rotating in a drum. The most commonly used pulverizer fuel system is the direct fire unit in which the coal is pulverized near the point of use. At this point, the pulverized coal has reached a mixture of fine particles of coal and is swept through pipes into the furnace. Coal dust or gases that are emitted from a freshly crushed coal is hazardous when present in the air in sufficient quantity. If a dangerous combustible mixture is created in the atmosphere, an explosion will result if the cloud of dust is ignited.