During operation, material is poured into the feed funnel, directed to the center of the rotor and propelled outward through the rotor channels. The controlled air flow, produced by the rotor and the centrifugal force, carries the material outward. In traveling outward the material is accelerated tangentially and radially to reach maximum velocity at the rotor rim. Here, the material leaves the rotor at an angle determined by the combined tangential and radial velocity components, and is thrust against an impact block. The material is shattered along its natural structure lines. The shattered material is carried by the air flow to the scroll area of the mill for discharge to a cyclone and connecting container or classifier. Besides carrying the material out of the unit, the air flow constantly cools the equipment and product, and cleans the interior of the mill.
Vortec Products Company has developed a complete line of Impact Mills for particle size reduction of material to fine or ultra fine powder. The Vortec Impact Mill offers controlled size reduction with a minimal production of undesirable fines at a fraction of the cost usually required to do the same task with a typical jet mill or ball mill.
The air swept machine relies on particle kinetic energy for size reduction. It accelerates each particle mechanically and thus directs particles to impact upon stationary impact blocks. Control over particle size reduction is attained by varying either the speed of the machine or the target distance to provide a suitable particle kinetic energy level that affects each particle. Size reduction is enhanced by increasing the particle’s kinetic energy level. Conversely it is minimized by reducing kinetic energy. The Vortec Impact Mill maximizes product yield by controlling the quantity of undersize particles produced as follows. Kinetic energy is impacted to each particle in proportion to the particle size. Since the propensity for fracture varies with the particle’s kinetic energy, small particles in feed stock will fracture less than larger particles. Material is removed from the Vortec Impact Mill after a single impact. Thus, particles that have been reduced to the desired size may be removed immediately after being produced. Energy is not wasted because it is supplied only to particles requiring size reduction.
A comparable jet pulverizer to the Vortec M-1 Impact Mill requires a 100 horsepower air compressor to create an inefficient fluid bed to carry the raw material for impact against itself. Multiple impacts are required for size reduction leading often to a high percentage of undersized product. In addition to the large air compressor requirements and its associated electric power expense, expensive air dryers and large capacity dust collectors are required. The Vortec M-1 Impact Mill uses a 7 1/2 horsepower motor, a 5 to 10 horsepower high capacity, low pressure air compressor, and a dust bag or small dust collector. Capital and operating expenses are considerably less for a Vortec M-1 Pulverizing System.
Accessories are available to operate the mill in an inert atmosphere for milling of highly flammable or explosive material . Accessories are also available for cryogenic milling of difficult material such as plastic, rubber, fibrous material, material with low melting point, and material with high oil contents. The mill is capable of milling material as cold as -300°F. For precise product size requirements, the Vortec M-1 Mill can be operated in tandem with the accurate Vortec C-1 Particle Classifier.