Apparatus for working rubber compounds

Abstract From the Canadian patent

An extruder for working rubber and other elastomeric compounds having an extruder screw with a feed section, metering section and a transition section. The transition section has a plurality of working sections in succession with each section having a pair of helical flights defining a pair or primary channels. One of such helical flights has a flight that leads off to define a secondary channel for leading off the portion of the compound subjected to a shearing action from the primary channels. The primary channels decrease in volume while their axial width remains the same. The secondary channel increases in axial width and depth to accommodate the worked rubber compound.