WGS (Waterfree Guided Strand) Pelletizer

The melt cooling-granulation step, at the end of a screw extrusion process, is a crucial issue and manufacturers have developed a number of solutions and for example:

  • Strand - Water bath;
  • Die face – Water ring;
  • Die face - Under water.
  In all above cases the cooling medium is water which is in direct contact with melt and must be filtered and recycled.
There are at least three good reasons suggesting to develop a new cooling-pelletizing system able to avoid the direct melt-water contact:
  • Many polymer melts, in contact with water, undergo severe hydrolytic degradation (e.g. PA,PC,PET etc.)
  • Speaking about the Strand – Water bath, no effective way is currently available to automatically repair strands when breaking. Such inconvenient requires always a difficult manual intervention and sometimes causes the entire cooling process breakdown. Similar troubles arise when long fiber reinforced strands are being cooled, as in this case the strands undergo uncontrolled deformation and cooling process instability.
  • Equipment to separate water from pellets and dry the pellets is expensive and energy and space consuming
Since long Nexxus has started a development of a new cooling-pelletizing system aiming to eliminate all above drawbacks. This new equipment deserves a particular interest as it is a natural completion of long fibers pellets technology, but it may be me successfully extended in general to all types of strand granulation.
The new system has been designed to:
  • Cool the melt with steel contact, which at turn is water cooled
  • Guide the strands up to the cutter in a way that self-repairing in case of breakage is fairly possible.
  • Grant uniform strands extrusion even with multiple strand dies
  • No strand number limitation
The technology is in an advanced step but still needs some time to complete validation @ 2014 Nexxus Channel All rights reserved / P.Iva 03001710122 / Design and develop: