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US 4,938,605 AGranted
Apparatus and method for mixing and continuous extrusion of a plastic mass
AssigneeWerner & Pfleiderer
InventorReinhard Friedrich
Life of this patent
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AssigneeWerner & Pfleiderer
InventorReinhard Friedrich
Estimating the term…
An apparatus for the mixing and continuous extrusion of a plastic mass having a first stage in which an intermittently operating mixer receives the starting materials batchwise and a second stage having a screw extruder which is supplied at periodic intervals, with material from the intermittent mixer. In order to provide a simple, inexpensive apparatus for two-stage mixing and extruding in which the full output of the first stage can be used and, independently of the state of the intermediate product, a continuous feed of material into the screw extruder of the second stage is effected. The second stage has mixing and kneading blades continuously rotating within a trough and an extrusion screw which extends along the bottom of the trough into an extrusion cylinder. A continuous drive motor for the extrusion screw is controlled so that the trough is always filled at least to 25% of its volume.
An apparatus for the mixing and continuous extrusion of a plastic mass comprising a first stage including an intermittently operating mixer to which starting materials are fed batchwise and a second stage including extruder means supplied at intervals by the intermittent mixer and comprising a mixing and kneading device including mixing and kneading blades continuously rotating in a trough, an extrusion screw extending in said trough beneath said blades and an extrusion cylinder projecting from said trough and into which said extrusion screw extends, drive means for continuous drive of the extrusion screw and control means connected to said drive means for operating the same to maintain an amount of material in said trough representing at least 25% of the volume of the trough.
A two stage method for mixing and extruding a plastic mass comprising adding batchwise materials to be mixed into an intermittently operated mixer, mixing the materials in the intermittently operated mixer, intermittently discharging the mixed material from the mixer into a buffer trough of a second stage mixing and extrusion apparatus, continuously supplying the mixed material from the buffer trough into continuously operating mixing and kneading blades in the second stage, continuously feeding the thus mixed and kneaded material by the mixing and kneading blades into an extrusion screw, continuously transporting the material by said extrusion screw and extruding and discharging the material from the second stage, sensing the amount of material in said trough and driving the extrusion screw in response to the amount of material in said trough to maintain an amount of said material in said trough representing at least 25% of the volume of said trough.
Dependencies are inferred from the claim text.