How to optimize continuous processing and make it work in pharmaceutical manufacturing is a crucial issue. Real-time devices for continuous feeding processes, among many other topics, were discussed at a seminar I attended last week. The seminar, “Advances in Pharmaceutical Processing”, was sponsored by K-Tron, which supplies material handling and feeding systems.
Feeders set the precise throughput to a downstream, continuous process, explained Sharon Nowak, global business development manager for food and pharmaceuticals at K-Tron, in a presentation at the seminar. Feeding performance can thus largely affect the performance of subsequent unit operations. Continuous processes generally use gravimetric (rather than volumetric) feeders because gravimetric feeders use loss-in-weight controllers that give more real-time information and are therefore more accurate than volumetric feeders. The need for accuracy in the pharmaceutical industry is even greater than that of the plastics or food industries, and the accuracy of feeders is now being examined at shorter intervals, down to one-second sampling. In addition, feeders are being tested and optimized for accuracy at very low rates. Nowak’s presentation explored various ways to optimize feeders and improve accuracy.
Real-time data can also be used to control other aspects of material flow. For instance, hopper flow aids, such as vibrators or agitators, are commonly used to keep poorly flowing material from forming ratholes or bridges that would prevent consistent material flow out of the hopper. Conventional vibrating devices, however, can cause material packing because of too much vibration. K-Tron’s ActiFlow device uses real-time feedback about flow conditions to start and stop vibration so that the hopper is vibrated just enough to restore good mass flow. I think this is an interesting example of applying real-time data to process control.
Better understanding of how to use real-time data, built-in calibration, and on-line controls are a good step towards implementing continuous manufacturing in pharmaceutical processes.