Intermeshing twin-screw extruders

The throughput rate of intermeshing twin-screw extruders (Fig. 18-56) and the Farrel continuous mixer (Fig. 18-51) is scaled up with diameter to about the 2.6 power. 

These two-phase polymers are generated in an optimized single-stage process using a corotating, close-intermeshing, twin-screw extruder. 

Mack, M., Corotating Intermeshing Twin-Screw Extruder Berstorff s System, Chapter 5 in Plastics Compounding Equipment and Processing, Todd, D.B. (Ed.), Hanser Publishers, Munich (1998)... 

In addition to single screw extruders, there are twin and multiscrew extruders that perform essentially the same functions, but with additional benefits. Among these, the intermeshing twin screw extruders are the most important ones. They are used primarily for heat-sensitive resins (such as PVC), which are difficult to process. The intermeshing screws create a relative motion of one flight in another, such that it acts... 

Fig. 26. Typical mixing elements for a co-rotating intermeshing twin-screw extruder...

Fig. 27. Progressive dispersion of calcium carbonate in polypropylene within a co-rotating intermeshing twin-screw extruder. Filler dispersion is expressed in terms of a mean volume diameter determined by image analysis...

Bigio D, Wang K. Scale-up rules for mixing in a non-intermeshing twin-screw extruder. Polym Eng Sci 1996 36(23) 2832-2839. 

Several studies have been performed to evaluate the mixing capabilities of twin screw extruders. Noteworthy are two studies performed by Lim and White [12,13] that evaluated the morphology development in a 30.7 mm diameter screw co-rotating [28] and a 34 mm diameter screw counter-rotating [3] intermeshing twin screw extruder. In both studies they dry-mixed 75/25 blend of polyethylene and polyamide 6 pellets that were fed into the hopper at 15 kg/h. Small samples were taken along the axis of the extruder and evaluated using optical and electron microscopy. 

Co-rotating, intermeshing twin screw extruder The Banbury... 

F. Busby, T. W. McCullough, K. R. Hugues, and R. O. Kirk, Melting of Homopolymers in Corotating, Intermeshing Twin-screw Extruders, SPE ANTEC Tech. Papers, 54, 3571 (1996). 

C. E. Wyman, Theoretical Model for Intermeshing Twin Screw Extruders Axial Velocity Prohle in Shallow Channels, Polym. Eng. Sci., 15, 606-611 (1975). 

Co-rotating, Fully Intermeshing Twin Screw Extruders, 572... 

Fig. 10.4 Hexalobal, intermeshing, counterrotating twin-screw mixing screw elements. [Reprinted by permission from W. C. Thiele, Counterrotating Intermeshing Twin Screw Extruders, in Plastics Compounding—Equipment and Processing, D. B. Todd, Ed., Hanser, Munich, 1998.]...

Flow and Mixing in Counterrotating, Intermeshing Twin Screw Extruders... 

CO-ROTATING, FULLY INTERMESHING TWIN SCREW EXTRUDERS... 

K. J. Gadzenveld and L. P. B. M. Janssen, Scale-up of Counter-rotating Closely Intermeshing Twin Screw Extruders without and with Reactions, Polym. Eng. Sci., 30, 1529-1536 (1990). 

S. Satija and C. S. Tucker, Effect of Screw Root Profile on PMMA Melting in Counterrotating Non-intermeshing Twin Screw Extruder, SPE ANTEC Tech. Papers, 40, 248-255 (1994). 

K. Nguyen and J. Lindt, Finite Element Modeling of a Counterrotating, Non-intermeshing Twin Screw Extruder, Polym. Eng. Sci., 29, 709-714 (1989). 

T. Sakai, Intermeshing Twin Screw Extruders, in Mixing and Compounding of Polymers, I. Manas-Zloczower and Z. Tadmor, Eds., Hanser, Munich (1994). 

T. W. McCullough and B. T. Hilton, The Extrusion Performance of Co-rotating, Intermeshing Twin Screw Extruder Screw Elements-An Experimental Investigation, SPE ANTEC Tech. Papers, 39, 3372-3379 (1993). 

J. P. Christiano and M. Lindenfelzer, Investigation of Mixing Patterns in Co-rotating Fully Intermeshing Twin Screw Extruders Mixing Elements Using Dynamic Pressure Distributions, SPEANTEC Tech. Papers, 43, 78-83 (1997). 

Theoretical volumetric flow rate in a counterrotating intermeshing twin screw extruder (10.2-2)... 

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