The classification of the extruder(1)

Single screw extruder plays an important role as both plasticizing and granulating machinery and forming and processing machinery. In recent years, single screw extruder has made great development. The large single screw extruder for granulation produced in Germany has a screw diameter of 700mm and an output of 36t / h.

The main sign of the development of single screw extruder lies in the development of its key part - screw. In recent years, people have done a lot of theoretical and Experimental Research on screws. Now there are nearly 100 kinds of screws, including separation type, shear type, barrier type, shunt type and wavy type.

From the development of single screw, although the single screw extruder has been relatively perfect, with the continuous development of polymer materials and plastic products, more characteristic new screws and special single screw extruders will emerge. In general, the single screw extruder is developing towards high speed, high efficiency and specialization.

Twin screw extruder has good feeding characteristics, is suitable for powder processing, and has better mixing, exhaust, reaction and self-cleaning functions than single screw extruder. It is characterized by its advantages in processing plastics and blends with poor thermal stability. In recent years, foreign twin-screw extruders have developed greatly. Various forms of twin-screw extruders have been serialized and commercialized, and there are many manufacturers. They are roughly classified as follows:
(1) according to the relative position of the two axes, there are parallel and conical;
(2) according to the meshing procedure of two screws, there are meshing type and non meshing type;
(3) according to the rotation direction of the two screws, there are the same direction and different direction, and there are inward and outward in the different direction; □
(4) according to the screw rotation speed, there are high-speed and low-speed;
(5) according to the structure of screw and barrel, it can be divided into integral and combined.

On the basis of twin-screw extruder, in order to process blends with poor thermal stability more easily, some manufacturers have developed multi screw extruders, such as planetary extruder