1,029,295. Screw conveyers. KALLE A.G. Nov. 22, 1962 [Nov. 22, 1961], No. 44268/62. Heading B8A. A screw conveyer for conveying, kneading extruding, cooling, heating or drying plastic or other substance is provided with two interengaging screws which rotate in the same direction, each of which screws has a thread, the cross-section of which includes a concave flank F and a convex tip K. The two screws are mounted parallel and close together such that the thread of one screw engages the hollow of the other screw and cleans it from caked material.
