3.1.13 Aspiration section
To clear the dust that may have accumulated inside the equipment due to dumping of various ingredients in the hoppers, bins and other equipment, localized aspiration system (Fig. 3.15) operated with compressed air and having bag filters and blowers are provided in all dust generating areas like elevators, conveyors etc. in the plant. The dust powder collected by aspiration system is put back to the process line for minimizing the process loss. Air breathers are provided on top of hoppers/ bins for releasing air and arrest dust. In some equipment, air balancing ducts are provided to neutralize the pressurized dust air. In case of pellet cooler aspiration system, instead of bag filter, cyclone with air lock, and blower with ducting are provided. The outlet emission of pellet cooler cyclone should be within 150 mg / cu m. All bolted joints in equipment, conveyors are provided with silicon sealant / good quality felt packing to arrest leakage of dust through joints. QC officer should check periodically the proper functioning of the compressed air based jet filler system of these aspiration units and also ensure that these filler bags are not torn due to continuous use.
Fig. 3.15 Aspiration system
