THE POWER-CONSUMPTION-CONTROLLED EXTRUDER - A TOOL FOR PELLET PRODUCTION

Based on the assumption that there is a link between power consumption of an extruder and pellet properties, a control circuit for power con sumption was developed. Powder and granulation liquid are feeded separ ately into a twin-screw extruder. The power consumption is controlled by varying the pump rate at a given powder-feed rate; consequently eac h level of power consumption results in a specific water content of th e extrudate for a particular formulation. The shape of pellets depends almost entirely on the level of power consumption irrespective of for mulation. The size of dry pellets is additionally affected by a shrink ing factor which depends on the water content. The power-consumption-c ontrolled extruder is an appropriate tool for the production of pellet s. The system is able to adapt the water content for a formulation aut omatically.