Coperion K-Tron Pitman, Sewell, NJ – sister company to Coperion (see above) – reports that it has developed an accurate feeding system for calcium carbonate (CaCO3) used as a mineral filler for plastics compounding. This takes into account the characteristics of the filler (for example, particle size and shape, gas permeability, bulk density and angle of repose) and the required feed rate. Loss-in-weight feeders provide dustproof containment of the raw material. 

While a single screw feeder may work well with free flowing grades of CaCO3, a twin-screw feeder is generally recommended to achieve a reliable result. A choice of screw designs is available to suit the flow rate and characteristics of the filler. A hopper of the appropriate shape and size needs to be selected based on the refill requirements of the feeders, a general rule-of-thumb being 12 hopper refills per hour with a maximum fill level in the hopper at 80% of the hopper volume. www.coperionktron.com 

 

 

To prevent flooding with free flowing grades of CaCO3 , twin-screw feeders are recommended and (right) a wide choice of screw designs is available