Twin-screw extruder structure and type

1. Structure and type

The twin-screw extruder is composed of several parts such as the transmission device, the feeding device, the barrel and the screw. The function of each part is similar to that of the single-screw extruder. Its structure is shown in Figure 1. The difference from the single-screw extruder is that there are two parallel screws in the twin-screw extruder placed in the '∞' cross-section material.

The twin-screw extruder used for profile extrusion is usually tightly meshed and counter-rotating, although a few also use co-rotating twin-screw extrusion, generally operated at a relatively low screw speed, about 10r/min . High-speed meshing co-rotating twin-screw extruder, used for compounding, exhaust or as a continuous chemical reactor, the maximum screw speed range of this type of extruder is 300-600r/min. Non-intermeshing extruders are used for mixing, venting, and chemical reactions, and their conveying mechanism is quite different from that of intermeshing extruders, which are closer to those of single-screw extruders, although they are fundamentally different.

2. Daily protection

1. After 500 hours of use, there will be iron filings or other impurities from the gear grinding in the gearbox. Therefore, the gears should be cleaned and the lubricating oil of the gearbox should be replaced.

2. After using it for a period of time, it is necessary to conduct a comprehensive inspection of the extruder to check the tightness of all screws.

3. If the power is suddenly cut off during production, the main drive and heating are suspended. When the power is restored, each section of the barrel must be heated to the specified temperature from the beginning and kept for a period of time before the extruder can be started.

4. If it is found that the surface and the pointer are fully turned, check whether the contact of the thermocouple equilateral line is released.