Apparatus for processing extrudable materials

Apparatus for processing extrudable material comprising:

• (a) a housing having opposite ends and a pair of spaced inlets for admitting material and an outlet intermediate said inlets for processed material;
• (b) a first shaft mounted for rotation within the housing and supported for rotation by bearings at its ends, said first shaft carrying first and second screws each extending from one of said inlets to the outlet, said screws having opposed threads for transporting material from the inlets to the outlet, such that forces exerted on one support bearing by the first screw acting on the material to be processed are at least partially compensated by forces exerted on the other support bearing by the second screw;
• and
• (c) a shear generating device located in the region of said outlet and comprising a first sleeve fixed relatively to the housing, said first shaft extending through said first sleeve and forming an annular gap with said first sleeve, and a transfer passage extending through said first sleeve and connecting the annular gap with the housing, whereby material transported by the screws towards the outlet is subjected to shearing force by passage through said annular gap.