As anyone who works with bulk solid materials knows, accurately and reliably controlling the flow rate of material at normal process rates can be challenging. Add to the challenge the need to control the flow of some minor ingredients in the process in micro-regions as low as 20g/hr. Further compound the challenge by requiring a level of precision that permits only a scant few percent sample-to-sample variation. This is the challenge of microfeeding.
The development of microfeeding technology emerged primarily as a result of the recent decade’s shift toward Process Automation Technology (PAT) as sanctioned by the FDA. This initiative has hastened application of continuous processing techniques in the pharmaceutical industry. Moving to a continuous process necessitates the elimination of manual feeding of minor ingredients and creates a real need for microfeeding technology.
The successful development of microfeeding technology represents a much needed response to the pharmaceutical industry’s requirement, and also offers processors in other industries a previously unavailable capability. A microfeeder can be applied in a variety of processes and industries: the micro-introduction of a powdered concentrate in plastics compounding, a trace component in energetics production, an option in low rate feeding of smaller sized micronizers, or as a continuous, on-line alternative to the traditional batch pre-mix approach for minor ingredients and additives.
Adopting a Microfeeding Mindset
Before addressing the design challenges of microfeeding it is important to first shift focus from the familiar notions of typical process feeding to the micro-realm of ultralow-rate feeding.