| 摘要 |
<p>1. An extrusion apparatus comprising : a hollow rotatable cylinder (10) having a plurality of circumferentially spaced extrusion ports (11) ; a stationary arcuate formation (14) disposed within the cylinder (10) ; a pipe (30) arranged to feed extrusion material into the interior of the hollow cylinder (10) ; characterized in that : - the stationary arcuate formation (14) has a base (39) at a distance from the inner wall (15) of said hollow cylinder (10) and a plurality of lands (40-46) extending between the base (39) and the inner wall (15), the spaces between adjacent pairs of lands (40-46) defining passages (48-53) aligned with the extrusion ports (11), such that extrusion material is fed by the rotation of the hollow cylinder (10) into the passages (48-53) ; - each of said passages (48-53) of said stationary arcuate formation has an individually adjustable dam mechanism (65-70) movable relative to the stationary arcuate formation (14) and extending into the passage, thereby providing a restriction within said passage, the size of this restriction being variable by movement of the dam mechanism relative to the stationary arcuate formation (14), the restriction serving to increase the pressure of extrusion material fed into the passages (48-53), thereby forcing extrusion material out of the extrusion ports (11) while the latter move along the passages (48-53).</p> |
