Study on Extrusion Characteristics of the Tri-Screw Extruder

Abstract

A novel kind of extruding machinery is proposed—a tri-screw extruder (TRISE), in which three intermeshed screws are arranged in the three corners of a triangle; three meshing regions and a center zone also comprise the special construction. The flow rate and the pressure-generating ability of the melt in the thread-zone flow field of the tri-screw extruder, especially the pumping formed by the action of taking in and sending out melt in the unique center zone, are also described. The results of simulation and experiments clearly show that the tri-screw extruder has stronger conveying capacity. The shear frequency of material in the tri-screw extruder is higher than that in the twin-screw extruder, which means that filler could be loaded to a much higher point in the TRISE than in the twin-screw. Results from the TRISE also show that energy consumption of the TRISE is lower than that of the twin-screw extruder.

Keywords:

• Central zone
• Extrusion characteristic
• Meshing region
• Simulation
• Tri-screw extruder

ACKNOWLEDGMENT

The authors wish to thank the engineers and workers of Jingjing factory in Zhejiang province for their courage and insight to invest in constructing the new machine and doing much to refine it.

Notes

A _φ, The smallest area of center region (mm²).

A _b , The area of the tri-bore of the barrel (mm²).

A ₀, The free area of the flow channel (mm²).

δ = A _φ/A ₀: The ratio.