Three Screw Granulator

The triple screw granulator is widely recognized for its flexible and diverse geometric arrangement, which allows for multiple zones of engagement to form material flow and velocity variations, as well as beneficial effects on the spatial distribution of particles, resulting in excellent mixing characteristics, a smaller length-to-diameter ratio, and a higher production capacity compared to other types of granulators.

The structure of the three-screw granulator is characterized by three screws arranged in a zigzag and rotating in the same direction, which is equivalent to the output of two pairs of twin-screw three-screw extruders.

1. Sufficient melting and even dispersion: The three screws arranged in a row produce strong compression and kneading, resulting in excellent plasticizing effects. This is due to the presence of two meshing zones, which double the compression range and make dispersion more even.
2. High output: For example, the three-screw extruder can produce 80% high-concentration filler masterbatch in one step without high-shear, with an output of 350 kg/hour. However, the double-screw extruder cannot produce 40% high-concentration filler masterbatch without high-shear compounding or repeated production, with an output of only 60 kg/hour.
3. Environmentally friendly and energy-saving: For example, with a 75 kW motor running at 500 rpm, the three-screw extruder can produce 50% carbon black masterbatch at 180 kg/hr, with the main motor current at 90 amps. The specific power consumption is only 0.2-0.25 kW/kg.
4. High-quality products.

One of them is the production of 50% concentration conductive carbon black masterbatch by twin-screw extruder, which requires compounding, while the three-screw granulator does not require a compounding machine, and the material can be directly fed into the three-screw granulator to produce 50% concentration carbon black masterbatch. If you bite the masterbatch, it will collapse and have cracks but not break, indicating that the masterbatch has good toughness. Why is that? Because it is fully melted and the components are evenly dispersed, allowing for the production of a film as thin as 0.005mm with uniform results.
If a high-shear device is used, the three-screw granulator can produce a higher concentration carbon black masterbatch with excellent toughness.

The second is the production of 85% calcium carbonate-filled PE or PP masterbatch by twin-screw extruder, which can be crushed by hand with a simple squeeze. However, the same formulation masterbatch produced by the three-screw granulator can be crushed by hand without breaking, and it cannot be crushed by a centrifugal dehydrator.
The third is the production of PP flame-retardant cable material, which has a strength of 13 MPa and an elongation of 185% after compounding by a twin-screw extruder with a length-to-diameter ratio of 40.
However, the material produced by the three-screw granulator without compounding has a strength of 14 MPa and an elongation of 237%. In addition, the three-screw granulator can produce a masterbatch with a filler content of up to 70% of aluminum powder or trioxide of antimony, while the twin-screw extruder cannot.