The twin-screw extruder can be classified from the mesh […]
The twin-screw extruder can be classified from the meshing or not, whether the direction of rotation is in the same direction or in the opposite direction, and whether the axis of the screw is parallel: whether the parallel twin-screw axes are parallel, the conical twin-screw meshing type counter-rotating, the parallel twin-screw partial meshing Part-type meshing type, non-intermeshing type rotating in the same direction, rotating in the opposite direction, using less (1), meshing type co-rotating twin-screw extruder: the speed of the twin-screw in the same direction is opposite at the meshing position One screw pulls the material into the meshing gap, and the other screw pushes the material out of the gap. As a result, the material moves from one screw to the other and advances in a "∞" shape. Since the gap of the meshing zone is small, the speed of the meshing screw and the groove are opposite in direction, so that the cutting speed is high, and the self-cleaning effect is good, that is, any accumulated material adhering to the screw can be scraped off, thereby。
The residence time of the material is very short, so the meshing type co-rotating twin-screw extruder is mainly used for mixing and granulation. (2) Meshing type counter-rotating twin-screw extruder In the meshing counter-rotating twin-screw extruder, the two screws are symmetrical, and the spiraling of the material on one screw is another due to the different directions of rotation. The screw of the root screw is blocked and cannot form a "∞" type movement. In the solids transport section, the material is transported forward in the form of an approximately closed "C" shaped chamber. However, in the design, a certain amount of clearance is left between the outer diameter of one screw and the root diameter of the other screw, so that the material can pass through. When the material passes through the radial gap between the two screws, it is strongly sheared. Stirring and calendering, so the material is better plasticized, and at the same time it gradually reduces the pitch to obtain the compression ratio, which is mostly used for processing products. (3) Non-intermeshing counter-rotating twin-screw extruder: the application is less than the meshing type, and its working mechanism is different from that of the meshing type, but similar to the single-screw extruder, that is, the material is conveyed by friction and viscous drag.