Bulk Density of Plastic Pellets in a Screw Channel

Abstract

Abstract For a correct calculation of the material throughput of single screw extruders in the by solids dominated feed area, the accurate knowledge of the effective bulk density is important. In the screw channel the bulk density measured in a quasi infinite vessel cannot be achieved during processing. The effective density is reduced according to the wall influences. If a two component system exists in the feed area, for example, when processing moulding compounds or regrind, then the bulk density changes likewise. In the following a procedure is described, by which the effect of the screw core measurement and the percentage composition of two material mixtures on the effective bulk density can be calculated.