The effect of batch size on scale-up of a pharmaceutical granulation in a fixed bowl mixer granulator

The effect of two batch sizes of a pharmaceutical granulation processed in a fixed bowl mixer granulator has been evaluated using the classical dimensionless numbers, Power, Reynolds and Froude recently shown to apply to this type of mixer. Despite a correction for the differences in the heights of the powder bed the relationships were significantly different. This is thought to be due to the differences in the downward force acting on the impeller as a result of the changes in flow pattern as the powder bed contacts the sloping sides at the top of the mixer.