| 摘要 |
<p>Screw extruders, especially cold feed plastics extruders, in which an extruder screw (18) is mounted for rotation in a bore (20) of a barrel portion (10, 14, 16). The screw extruder comprises at least one roll mounted for rotation adjacent an aperture (26) in the barrel portion (10, 14, 16) so that a surface portion of the roll (24) restrains material from leaving the barrel portion (10, 14, 16) through the aperture (26) and heat transfer can be effected between the material and the roll (24). Preferably there are two such rolls (24), diametrically opposed and heated or cooled. The rolls (24) are rotated in the operation of the extruder, preferably by variable speed drive units (28), in carrying out a method of effecting heat transfer according to one aspect of the invention. </p> |
