COMPOUNDING: Two-Stage System Packs Power in Smaller Footprint

Designed for heat- and shear-sensitive materials.

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Coperion, Stuttgart, Germany (U.S office Ramsey, N.J.) has redesigned its Kombiplast KP two-stage compounding to make it more compact and more energy efficient than previous iterations. It is even said to provide higher throughputs.

Designed for heat- and shear-sensitive materials, the Kombiplast teams a ZSK twin screw extruder equipped with a ZS-B twin screw side feeder with an ES-A downstream single-screw extruder that gently builds up sufficient pressure for pelletizing.

Coperion reports that PVC fittings molder Formatura Iniezione Polimeri SpA (FIP) has installed the first unit of the new, improved series (a KP 62 Mv PLUS/200) at its facility in Casella, Italy. This system is being used for compounding tailor-made rigid PVC compounds at a throughput rate of about 3500 lb/hr.

Coperion's patented Feed Enhancement Technology (FET) is incorporated in the ZS-B twin screw side feeder of the Kombiplast. There, the feeding zone is provided with a porous, gas-permeable wall section to which a vacuum is applied externally, permitting extraction of the air between the particles and hence considerably improving the material intake capacity in the processing of feed limited products, such as dry blends. The improvement to feed behavior has a positive effect on operating reliability and, as a result, production rates and compound, Coperion explains.

Another part of the system that has undergone fundamental improvement is the ES-A single-screw discharge unit: The barrel is now cooled with water instead of air. This result in a reduction in electricity consumption and an improvement in the accuracy with which the temperature profile can be set and controlled. The ES-A is now driven by a geared motor, which cuts down on the height of the machine base to reduce footprint.  For better pelletizing performance, both the drive and the rotor bearings of the EGR eccentric pelletizer have been improved: the knives can be set more accurately, thus ensuring a consistently uniform length of chopped pellet.