Granulation monitoring by fast Fourier transform technique

Abstract

In the wet granulation process with a high speed mixer, the fast Fourier transform (hereinafter FFT) technique with a personal computer was adopted to perform concurrent precise analysis of the vibration to monitor the granulation process. In this study, a vibration pattern was obtained by inserting a probe into the powder layer. The specific wave pattern of the vibration was observed as granulation progressed. The frequency of the wave was equivalent to that of the impeller blades of the high speed mixer. The elemental strength of the wave at the impeller blade frequency (hereinafter ESWF) converted by FFT exhibits a good relationship with the mass median diameter of the granules. It was demonstrated that the wet granulation process can be concurrently monitored and controlled by ESWF.