Background of the Screw Extruder (1)
The invention relates to a screw extruder for working plastic compositions, especially polymers and rubber mixtures, consisting of a cylinder in which a motor-driven screw is disposed, the cylinder of which is provided with pins which are arrayed in several planes perpendicular to the cylinder axis and can be inserted radially through openings in the cylinder wall, and the screw is provided in the spirals of the screw with gaps disposed in the planes of the pins.
Such screw extruders are disclosed in German Patent 137,813 and U.S. Pat. No. 1,848,236. The pins extending radially into the extruder cylinder improve the kneading and mixing of the material, and in many cases they have made such kneading and mixing possible for the first time.
When the screw is changed and when the extruder is to be cleaned these pins have to be removed and then reinstalled. When the pins are threaded in place it becomes possible to adjust their depth, which is done for the purpose of reducing the screw resistance by having the pins reach less deeply into the cylinder and to improve the kneading and mixing action by setting the pins deeper.
Such screw extruders are disclosed in German Patent 137,813 and U.S. Pat. No. 1,848,236. The pins extending radially into the extruder cylinder improve the kneading and mixing of the material, and in many cases they have made such kneading and mixing possible for the first time.
When the screw is changed and when the extruder is to be cleaned these pins have to be removed and then reinstalled. When the pins are threaded in place it becomes possible to adjust their depth, which is done for the purpose of reducing the screw resistance by having the pins reach less deeply into the cylinder and to improve the kneading and mixing action by setting the pins deeper.
