The mills type SV are designed for the fine or finest grinding of many materials of medium hardness and abrasiveness, such as:
• minerals (calcium carbonate, gypsum, limestone, antimony trisulfide, etc.)
• chemical products (calcium oxide, calcium oxide, aluminium hidroxide, petroleum coke)
• vegetable products (coals, dried vegetables, cocoa, etc)
• micronizing of cereals
These mills have an high speed vertical axis rotor on which some rigid hammers of suitable shape are fixed.
The grinding action is provided by impact against a toothed lining and by friction between layers of the processed material.
The product is pneumatically discharged upwards, through an air classifier. The dynamic classifier is designed according to the grinding requirement and is fitted onto the top of the mill.
The cage-type dynamic microclassifier fitted onto the mill is suitable to obtain powders at a fineness up to 99% finer than 20 micron, with an high percentage of particles finer than 5 micron. The oversize not passing through the micro-classifier falls down to the mill where it is further ground.
The drive of the micro-separator is independent and usually is made with a variable speed motor.
This allows a very fine adjustment of the working speed and the micro-separator directly from the control board.
Granulometry also depends on the mill’s speed and on the air flow.
The air flow, drawn through the mill by the exhaust blower, can be heated for drying moist products or can be cooled for treating thermo-sensitive products.
The air circuit is closed under inert gas when processing products subject to explosion risks.