| 摘要 |
Apparatus for extruding plastic material, rubber and other thermoplasts and elastomers comprises two screw extruders each having a casing with a cylindrical bore and with a feed inlet and discharge, an extruder screw rotatable in the cylindrical bore of the casing and drive means at the opposite end of the casing from the discharge for rotating the extruder screw. The discharge of the first extruder is connected to the feed inlet of the second extruder so that material extruded by the first extruder is fed into the second extruder. A vacuum is applied to the interior of the casing of the second extruder in the vicinity of the inlet opening in order to degas material received in the second extruder from the first extruder. At a point slightly downstream from the inlet of the second extruder there is provided pressure responsive means for sensing pressure variations in the bore of the extruder. Control means responsive to the pressure sensing means regulates the relative speeds of rotation of the screws of the first and second extruders so that the screw channel of the screw of the second extruder in the vicinity of the inlet opening is not completely filled, thus leaving a space in the passage through which the vacuum is applied to the material to obtain an effective degassing thereof.
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