Investigations on the residence time distribution of a three-chamber feed frame with special focus on its geometric and parametric setups

The feed frame is one of the key elements of a rotary tablet press. It ensures a uniform flow rate of powder from the funnel to the compression dies. An experimental study was conducted to investigate the residence time distribution of a three-chamber feed frame system (Fill-O-Matic). For this study, a Fette 102i rotary tablet press was used to simulate the conditions of the manufacture of tablets. The Fill-O-Matic consists of distributing, filling, and dosing chamber which together provide a large volume. For this reason, the influence of a geometric setup (filling cam and inner/outer scraper) and a parametric setup (die disc speed, feed frame speed, and filling depth) on the residence time distribution were determined with regard to the continuous manufacturing of tablets, an approach to optimize the configuration of the Fill-O-Matic. The results showed that the outer scraper has an influence on the residence time of the powder in the feed frame. An interesting output of the study was that an increase of the feed frame speed did not lead to an influence of the mean residence time. Instead, the intermixing of the powder, described as mean centered variances, increased by an increasing feed frame speed. (C) 2017 Elsevier B.V. All rights reserved.