How to distinguish the screw rotation of the twin-screw extrusion granulator?

The development of twin-screw extrusion granulator: it was successfully developed in Italy in the 1930s, and developed rapidly in the late 1960s and early 1970s. Hetero-rotating twin-screw is developed with the development of RPVC products, and the contract direction is developed with the modification of polymers. The research on the theory of twin-screw extrusion cannot adapt to the development of application. It has formed a consensus worldwide and has become The seminar is hot.

Compared with the parallel meshing counter-rotating twin-screw extruder, the volume of a series of C-shaped chambers composed of two screws and barrels gradually decreases from the feeding section to the discharging section. Add a larger volume of powdery material, as the screw becomes smaller, the material is compressed and melted. The aspect ratio of the screw refers to the ratio of the useful length of the screw to the outer diameter. Generally, the length-diameter ratio of the integral twin-screw extruder is between 7-18. For combined twin screw extruders, the aspect ratio is variable. From the perspective of development, the aspect ratio has a gradually increasing trend. The rotation of the screw is divided into the same direction and the opposite direction. Generally, co-rotating twin-screw extruders are mostly used for mixing, and counter-rotating extruders are mostly used for extruding products.

In the discharge section, due to the small diameter of the screw and the small peripheral speed of the screw, the shear rate of the material here is low, and the frictional heat generated is also small. It is suitable for processing heat-sensitive materials, so it is used to process PVC powder and directly process it into product. Introduction of thread curve correction method According to the theory, the theoretical axial curve of the screw thread can be obtained, but the meshing gap value of the theoretical curve is 0.