RAPRA'S GLITTERING PRIZE.

This article outlines the basic historical development of the single screw extruder and the theoretical considerations which have been used to develop the mixer for successful extrusion. It describes experimental work using two cavity transfer mixers of different length-to-diameter (L/D) ratios, to demonstrate the highly efficient mixing or blending action when used for rubber compounds. Applications for this new mixer have been outlined including use in rubber extrusion. Mathematical aspects of mixer design principles are also discussed.