| 摘要 |
A screw extruder having a cylinder, an extrusion head, a screw in the cylinder and a motor for driving the screw in rotation has insert members which extend into the cylinder to effect plastification and homogenization of the material being extruded. The web of the screw is provided with annular recesses into which the insert members project. Some of the insert members are stationary, in the form of pins projecting radially into the cylinder, while others are movable so as to vary the extent of their projection into the cylinder. The movable insert members may be pins extending radially into the cylinder and movable radially, rotatable threaded pins extending tangentially into the cylinder, rotatable pins extending tangentially into the cylinder and having non-circular portions in the cylinder, or sector-shaped discs which are movable pivotally. Actuators for the movable insert members are controlled by a processor which compares measured output temperature of the extrudant in the extruder head with a preselected temperature.
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