Multi-flighted screw geometry

In co-rotating twin screw extruders, in addition to flow splitting at the flight, further flow splitting takes place in the intermeshing zone (see Fig. 9.5). Furthermore, a multi-flighted screw geometry increases the number of partial flows. The number of partial flows equals... 

The conventional multi-flighted extruder screw has a number of advantages and disadvantages. The basic geometry is shown in Fig. 8.52. 

The Ingen Housz screw combines a barrier geometry with multi-flighted geometry to obtain significant improvements in melting. A picture of the barrier section geometry is shown in Fig. 8.62. 

The barrier section geometry is shown with the screw channel unrolled onto a flat plane. The solid bed is divided into several parallel solid channels. The melt is collected in several parallel melt channels. It is possible to achieve this multi-flighted geometry by a significant increase in the helix angle. The total melting length can be expressed as [27] ... 

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