| 摘要 |
<p>In an extruder for processing material to form an extruded product, the extruder (12) including an elongated extruder barrel (24) having a material inlet end (40) and an outlet end (42) remote from the inlet end (40), and a pair of elongated, axially co-rotatable, flighted extrusion screws (46, 48) within the barrel for moving material from the inlet end (40) towards and through the outlet end (42), the barrel (24) is provided with a pair of parallel bores (56, 58) which are formed with spiral grooved surfaces (64) along at least a portion of their lengths. An inlet opening (62) is provided adjacent the inlet end of the barrel such that one of the co-rotating screws (46) of the extruder rotates in a direction outward and downward from the inlet opening (2) and the other screw (48) rotates upward and toward the inlet opening. The bore (58) receiving the upturning screw is provided with a smooth surface region (66) adjacent the opening which prevents material entering the inlet opening (62) from being delivered back into the opening (62) by the upturning screw (48).</p> |
