3.1.4 Grinding operation
Grinding is the most effective processing technique to improve nutrient utilization and animal performance. For uniform particle size to ensure better quality pellets, the complete batch passes through the hammer mill (i.e100 per cent grinding after batching) prior to mixing. Thus grinding increases surface area of batch ingredients for improved rate of digestion, decreased segregation and mixing problems. Hence a grinding section has been provided with the plant to grind the complete batch materials to powder form. The grinding system consists of hopper, a rotary feeder with magnet, the grinding mill (Hammer mill; Fig. 3.5), collection hopper below mill, screw conveyor, elevator and aspiration system. The grindable raw materials are fed to the grinding mill by the rotary feeder through a magnet, where these materials are ground to powder. After grinding, the total powder batch is conveyed through conveyor and elevator and stored in hopper above mixer. Batch from this hopper is fed automatically to the batch mixer through a pneumatic flap. Quality control officer should ensure the particle size of grinded materials for proper mixing of raw materials. He should also ensure that the hammer mill sieve is of correct mm hole size and the same is not damaged so as to limit the ground particle micron sizes within the fixed norms
Fig. 3.5 Hammer mill
