Co-rotating self-cleaning multi-screw extruder with speed ratio of 2.5 and extruding method therefor

Abstract

A co-rotating self-cleaning multi-screw extruder with a speed ratio of 2.5 and an extruding method therefor are disclosed. The screw mechanism includes a center screw and peripheral screws which rotate in the same direction. The peripheral screws are each of a double threaded structure, and the center screw is of a quintuple threaded structure. The rotation speed of the peripheral screws is 2.5 times that of the center screw, and the peripheral screws are always meshed with the center screw, whereas the adjacent peripheral screws are intermittently meshed with each other. The extruding method therefor is as follows: there is a periodically open space between adjacent peripheral screws, providing the periodical and intermittent mixing action, so that material from different thread grooves is mixed with each other. Meanwhile, the topological chaos action, by which the material is cut into two portions, is formed between the center screw and the peripheral screws, and the chaos mixing is caused by the random motion which is generated from the periodical changes of the channel, so that a periodical action of 'compression-expansion' is achieved. Furthermore, due to the tensile force field action caused by the differences in rotation speed between the center screw and the peripheral screws, the compression preheating and dispersion mixing of the material are achieved. The co-rotating self-cleaning multi-screw extruder effectively improves the efficiency of conveying and mixing of materials.