Roller compactor powder flow

The chief objective of roller compaction is to consistently make an agglomerate of sufficient strength that meets required density, granulometry, and powder flow specifications. Operationally, the key goal of a compactor is to maintain a range of pressure on the feedstock, independent of the fluctuating powder granulometry and flow fed into the rolls, so that a consistent compact is made. 

In older roller compactors, the feed screw did not always adequately deliver the powder to the gripping and compaction zone due to stationary side seals which resist the flow. Factors affecting uniform distribution of compaction pressures were investigated by Funakoshi etal. (2S). The distribution of compaction pressures across the entire ribbon was estimated by determining the force needed to drill the ribbon at various locations. 

A history of hopper and feed screw designs showed that each design evolved to facilitate and improve powder flow to the compactor feed screw conveyance system. Feed hopper designs shown in Roller Compaction Technology for the Pharmaceutical Industry depict designs used in older compactor models (23). Dehont et al. described the powder compaction feeding systems that were in use up to 1989 (24). 

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