Gear pumps for compounding
Plastic compounding is a continual, multi-stage process using extruders where polymers and additives are mixed with each other in the melt phase. The discharge materials are dosed in the extruder. The material is mixed into a homogeneous melt in the extruder and then formed into small pellets in a granulator. A gear pump is normally in front of the granulator, which provides constant pressure build-up for consistent granulate. The end products include mono-pigment, additive master batches as well as filler and reinforced-fiber compounds. Large gear pumps are used in particular during the compounding of polyolefins such as LDPE, LLDPE, HDPE and PP.