This paper introduces the five system structure of twin screw extruder

Twin-screw extruder (screw and barrel) by extrusion system, the transmission structure (reducer, bearing and motor), feeding system, heating and cooling structure and control system of five parts, with single screw extruder, twin screw extruder barrel, two root screw, charging part adopts spiral forced feeding within the barrel, screw with bearing specifications and layout is more complex.

1. Extrusion system

1. Screw structure

It is the main part of the extruder. The screw tooth shape of twin screw in twin screw is not in accordance with the rules. It cannot form a closed mesh, which belongs to the non-sealing type. The screw is self-locking and is driven by gear. It is not in direct contact with the screw

2. Cylinder structure

A metal cylinder has the properties of heat resistance, abrasion resistance and corrosion resistance. The machine tube and the screw are combined to realize the crushing of plastic. The cylinder structure of twin screw extruder and single screw extruder are the same as the cylinder structure of the single screw extruder. In the double screw extruder, the meshing of the two screw extruder and the conical twin screw extruder usually adopt the monolithic cylinder; A small number of large extruders adopt piecewise composite cylinder to facilitate machining.

2. Transmission structure

The driving system is used to drive the screw and the torque and rotational speed required by the screw in the extrusion process, usually consisting of the motor, the gearbox and the bearing.

Double screw in the work when the axial force and work in single screw extrusion when the axial force is similar to or higher than that of single screw extruder of axial force, such a large axial force should need large size bearing to bear, but, as a result of the double screw work arrangement limits the screw under axial force in the bearing arrangement space, and thus how much bearing arrangement scheme.

3. Feeding system

According to the characteristics of extruder extruder and the working conditions, the feeding system of double screw extruder adopts the compulsory metering feeding method.

The feeding device is like a single screw extruder working independently, and the screw of rotating feed is driven by direct current motor through the output shaft of worm gear reducer. The rotation speed of the screw, the size of the feed material, the working speed of the twin screw extruder, the temperature of the cylinder, the material pressure of the products and the amount of material used. The screw thread in the feeding device is threaded. It can be single head or double head. The common application is single thread.

4. Heating and cooling structure

Heating and cooling are the basic conditions of the extruder, generally based on the resistance heating cylinder method. The commonly used structure of aluminum resistance wire heater is used. The heater is a metal tube that holds the resistance wire into a magnesium oxide insulating material and then casts the metal tube into a aluminum alloy casing.

V. control system

Control the operation and stop of twin screw extruder.