Extruder showing principle

Figure 12.1 Cross section of an extruder showing principle components.

Fig. 10 The NICA system radial-screen extruder. (A) Assembled unit. (B) Dismantled to show extrusion mechanism. (C) Cross section indicating working principle.

The schematic illustration already shows the principle of later de-airing extrusion machines, i.e. a primary pug mill A1 and a main extruder B3, which are coimected by a low-pressure chamber B, the actual vacuum chamber. In this system, the clay cushions formed inside the auger flights of the primary pug mill and main extruder serve as a sealing for the vacuum chamber, in which a negative pressure is produced by the vacuum pump E. This patent was acquired by Messrs. Chamber Brothers in Philadelphia, and was used to build de-airing extruders (Fig. 43). 

Figure 7 (A) Gravity-feed rotary extruder (B) close-up showing the extrusion zone (C) operating principle of gravity-feed extruder. (Courtesy of Niro Pharma Systems.)...

Figure 6 shows a simple extrusion line with extmder, transfer pipe, and die [5.] Also shown are the flows at the end of the extruder and out of the die. The flow oscillation is attenuated at the die by the absorption of some of the low disturbance in the piping according to hydraulic transient principles. 

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