Air classifier mill PPS Series

impactverticalfor powders

The mill type PPS are designed for the fine or finest grinding of many materials of medium hardness and abrasiveness, such as: • Powder coatings • Chemicals • Vegetable products (dried vegetables, cocoa, soia, cereals, wood flours) • Pesticides These mills have a high speed vertical axis rotor on which many vertical pins or hammers of suitable shape are fixed. The grinding action is provided by impact against smooth or toothed lining and by friction between layers of the processed material. The product is pneumatically discharged upwards, through an air classifier. The special design with coaxial shafts of rotor and classifier mounted on suitable bearings provide a compact construction and an easy installation. The dynamic microclassifier, with special shape and deflector, is suitable to obtain powders at a fineness up to 99% finer than 30 micron, with average diameter d50 adjustable in the range 2 – 20 micron with granulometry distribution in a narrow range. Fineness adjustment is made by changing the speed of the classifier, the capacity of the suction blower, and the speed of the rotor. The oversize not passing through the micro-classifier returns to the grinding area where it is further pulverized. Only the product with the requested granulometry is collected after the mill. The high flow of air (or other gas) and the mill’s design reduce the heat transfer to the product, compared with other type of pulverizing systems.