In the past, it was common practice to feed the additives manually in powder coating boxes. Later on, powder coating producers added additives at chips container. Finally the additive was fed by rotary airlocks upstream the mill, or by feeding the additives at the sieve after cyclone discharge.
The additive suction inlet allows the additive to be added in front of the mill (Fig. 1), the additive Injector adding agent between cyclone classifier and sieve (Fig. 2).
With the Suction Inlet, the additive is sucked, due to the negative pressure in the powder coating system, into the feeding pipe. The additive flows with the powder coating chips in the ICM (Impact Classifier Mill). In the mill, the additive is mixed with the powder coating. The disadvantage of this set-up is, that a significant part of the additive is lost at the cyclone collector into the filter. With the Additive Injector, the additive is fed by compressed air through the Injector into the NEA Additive Adapter. In the Adapter, the additive is mixed with the final product. In comparison with the Suction Inlet, the additive consumption with the Injector is lower. However, the additive dispersion is not as efficient.
Now a new system was designed to reduce the amount of additive and at once to improve significantly the dispersion in the final powder coating product.