Mixing and residence time distribution in melt screw extruders

Pinto, Gustavo; Tadmor, Z.

doi:10.1002/pen.760100505

Cited by 132 publications

(93 citation statements)

References 8 publications

(1 reference statement)

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“…Apart from their local pressure-generating or pressure-consuming capacity, the different screw geometries of the cokneader can be characterized by their residence time distribution RTD (16,17). provided the completely filled lengths are known.…”

Section: Residence Time Distributionmentioning

confidence: 99%

On the modeling of continuous mixers. Part II: The cokneader

Elemans

Meijer

1990

Polymer Engineering & Sci

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The Buss cokneader is a single-screw extruder with interrupted flights. Pins from the barrel are inserted into the screw channel. The screw is both rotating and oscillating. Due to this action, screw flights are continuously wiped by the pins. During one passage of the pin, the material is not only subjected to high shear stress, but it is reoriented as well, thus promoting the distributive mixing process by the local weaving action of the pins and screw flights. Attempts to model the cokneader tend to focus on a single pin passing through the hole in a screw flight (1,2). However, a more comprehensive model can start with the same equations that apply to the corotating twin-screw extruder (3). Because the effect of leakage flows on the local pressure gradient has to be considered along with the effect of the local dragging action of the pins (neglecting the oscillatory action), experiments with model liquids have been performed to evaluate the comprehensive model. Additional experiments with a Plexiglas-walled cokneader support the calculations concerning filled lengths in various screw geometries. These results, and those of model calculations, which are extended to the nonisothermal, nonNewtonian situation, are presented.

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Section: Residence Time Distributionmentioning

confidence: 99%

On the modeling of continuous mixers. Part II: The cokneader

Elemans

Meijer

1990

Polymer Engineering & Sci

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“…It should be mentioned that the original definition of WATS defined by Pinto and Tadmor [7] is slightly different to the definition Eqn. 9 and that the term Mean Total Strain seems to be more appropriate in this case.…”

Section: Mixing Measuresmentioning

confidence: 99%

Effects of geometry variations on the mixing ability of a shear-mixing-type screw head

Straka¹,

Steinbichler²

2016

AIP Conference Proceedings

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“…Lindt and Ghosh (1992) studied the fluid mechanics of the formation of polymer blends and suggested that the degree of mixing increases with the generation of interfacial area between the individual material components and with the residence time. Thus, the shear strain of the mixed composite will play an important role in the generation of this interfacial area (Pinto and Tadmor, 1970). breaker plate from 5-7 mm.…”

Section: Effect Of Glycerol and Holes Diameter On Machine Outputmentioning

confidence: 99%

Effects of Glycerol and Diameter of Holes in Breaker Plate on Performance of Screw Mixer for Nanocomposites

Fadeyibi

Osunde

2017

Agricultural Engineering

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A breaker plate of a screw mixer is an efficient mixing device for use in homogenizing nanocomposites. This research was undertaken to investigate the effects of glycerol and diameter of holes in a breaker plate on performance of a screw mixer for nanocomposites. Samples of the nanocomposites were formulated by blending 1000 g cassava starch, 45-55% glycerol and 2% magnetite nanoparticles; and used to evaluate the performance of a locally developed screw mixer at 5 mm and 7 mm diameters of holes in its breaker plate. The effects of glycerol and diameter of holes in the breaker plate on mixing index, amount of unmixed nanocomposites and output/ 1000g were evaluated as performance indices for 1 hour. Empirical models were determined for predicting the performance of the mixer within the designed criteria. The results showed that the output/ 1000g and the mixing index increased with higher glycerol and diameter of holes in the breaker plate. However, the amount of unmixed nanocomposites decreases with a higher diameter of holes in the breaker plate (p<0.05). The maximum output/ 1000g and mixing index lies between 5 mm diameter of holes in the breaker plate and 55% glycerol concentration with an approximate desirability of 0.60. The empirical models developed were fit (R 2 =0.89, p<0.05); and there were no significant differences between actual and predicted values. The results suggest application of 5 mm diameter of holes in the breaker plate for homogenizing nanocomposites for optimum performance.

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Mixing and residence time distribution in melt screw extruders

Cited by 132 publications

References 8 publications

On the modeling of continuous mixers. Part II: The cokneader

On the modeling of continuous mixers. Part II: The cokneader

Effects of geometry variations on the mixing ability of a shear-mixing-type screw head

Effects of Glycerol and Diameter of Holes in Breaker Plate on Performance of Screw Mixer for Nanocomposites

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