(273e) Comparisons Between Solid Plug Model Predictions for a Powder Roll Compactor Screw Feeder and Experimental Measurements

Comparisons between
solid plug model predictions for a powder roll compactor screw feeder and
experimental measurements

T. Patterson and C.
Wassgren, Purdue University

Abstract

Solid plug models previously developed to predict the
pressure distribution in extruded plastic pellets fed by a screw feeder are
evaluated in the present work for feeding pharmaceutical powders, specifically to
the inlet of the nip region in a roll compactor.  Experimental measurements of
the screw torque required to feed the powder at a given feed rate, the pressure
at the outlet of the feeder, and the powder bulk density distribution along the
axis of the screw are compared to corresponding predictions from the solid plug
models.  The screw rotational speed and outlet pressure are varied in the
experiments. The goal of the work is to use the measured screw feeder torque, a
parameter often available in commercial roll compactors, and the solid plug
model to predict the stress at the exit of the feed screw, and use this stress
as an input to Johanson's one-dimensional model for predicting the ribbon
density exiting the roll compactor.