Air Classifier Mill is a vertical grinding mill incorporating an internal air classifying wheel with an independent drive.
Product is fed into the grinding chamber by either a feed screw or a pneumatic conveying system via a rotary feed valve.
The product is impacted by the high speed grinding media, which causes the feed product to fracture and be thrown by the centrifugal force to the wall of the grinding chamber, which in turn, causes the product to fracture further. The fractured particles are entrained in the induced airflow liberating the outside wall of the internal baffle assembly, which is fitted with air baffles to laminar the air flow. The laminar airflow and particles pass to the internal classifier, which is rotating, in the same direction as the rotor disc. Oversized particles rejected by the centrifugal force applied by the classifying wheel are thrown to the inner wall of the baffle and move down by gravity and by the pressure created by the classifier.
The grinding chamber of the ACM houses both the components of the classifying and grinding zones. They include the impact rotor and hammers, the liner assembly, the shroud and baffle assembly and the classifier wheel. The grinding chamber can be designed to operate to 10 bar(g) overpressure for explosive materials.
Rotors are normally supplied as single discs; however options include reduced diameter rotors for use with heavy duty liners, and rotor discs with replaceable wear plates for abrasive applications. Hammers are bolted to the rotor disc and can be easily removed and replaced.
• Bar Hammers – for fine size reduction and maximum impact.
• Pins – for producing coarse particle size distributions and to minimize the generation of fines.
A liner is located at the grinding chamber wall. There are two basic types of liners; the multiple deflector (MD) liner is for fine size reduction and the smooth liner is for coarse size reduction and to minimize the generation of fines. The purpose of the liner is to provide for more efficient size reduction by slowing the peripheral speed of the particles and to deflect them back into the impact hammer path.