A novel crammer feeder that is controlled not by speed but by torque is the only known device that can successfully feed blown film fluff into an extruder with a grooved-feed-throat, which up to now was thought impossible.
A novel crammer feeder that is controlled not by speed but by torque is the only known device that can successfully feed blown film fluff into an extruder with a grooved-feed-throat, which up to now was thought impossible. So says the inventor of the device, consultant Eric Hatfield of Film Solutions & Technology Inc. in Cincinnati. The feeder is patented by Hatfield’s former company, Flextech, also in Cincinnati, which sub-licenses the unit to Hosokawa Alpine American, Natick, Mass. Alpine has built several units over the past two years and has designs to fit extruders of 65 to 120 mm diam. for LLDPE, HDPE, nylon, and EVOH films. Typically the crammer feeds 30% to 40% fluff with virgin pellets, but Alpine has successfully run lab trials with up to 100% LLDPE fluff. The torque-controlled feeder, which will be displayed for the first time at NPE 2006 in June, has another advantage: When used just with virgin pellets, it significantly increases output per screw revolution.