Roller compactor sizing granulators

Gereg and Capolla developed process parameters determined by a model laboratory bench scale Carver press, model C (Carver Inc. Savannah, Georgia, U.S.A.), which were translated to production scale compactor parameters (6). Their study provided a method to predict whether a material is suitable for roller compaction. Their study objectives were to characterize properties of the material to identify process parameters suitable to achieve the necessary particle size and density using the dry granulation process and then translate laboratory information to a production scale roller compactor. Actually, information developed from a Carver press was correlated and scaled-up to a production scale Fitzpatrick roller compactor. Model IR 520 (Fitzpatrick Co., Elmhurst, Illinois, U.S.A.) The compactor produced very similar powder granule characteristics as the Carver press. Various lactose materials, available as lactose monohydrate or spray dried lactose monohydrate, were used as the model compounds. Results indicated that a parametric correlation could be made between the laboratory bench Carver press and the production scale compactor, and that many process parameters can be transferred directly. 

Table 10 Roller Compactor Operating Conditions and Particle Size Distributions for 5% Active Granulation Trials...

Location In a roller compactor, the mill or granulator is often located after the rolls (as the formed ribbons exit) and before a screen. The mill reduces the ribbons into granules which pass through the screen which separates the over-sized granules from... 

Roller compactors are available in different designs and can be equipped with a variety of differently profiled rollers to produce compacted material, pellets, or briquettes. Usually, the compacted product then has to be milled to the desired particle size. To minimize dust and fines, which have to be recycled back to the compaction process, selection of suitable milling equipment is important. Gentle systems, such as roller mills or sieve mills, are preferred. As Figure 16.21 shows, compacted granules appear as more irregular, sharp-edged particles. 

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