UDY CYCLONE SAMPLE MILL
PRINCIPLES OF OPERATION
The Cyclone Sample Mill uses a high velocity air-flow, an abrasive surface, and centrifugal forces to grind material. Figures 1 and 2 identify the main parts. The Impeller rotates at a high speed creating the high velocity flow of air to propel articles against the abrasive surface.
When material is added to the Mill, the rotation of the Impeller and centrifugal force throw the particles to the perimeter of the Grinding Chamber where the air-flow pushes them along the abrasive tungsten carbide surface. When the particles become small enough, they move with the air-flow out of the Grinding Chamber and are deposited in a sample Collection Bottle by cyclone action.
The air-flow prevents accumulation inside the Grinding Chamber eliminating the need to clean out the Mill between samples. The air-flow also minimizes heating of the materials accumulation inside the Grinding Chamber eliminating the need to clean out the Mill between samples. The air-flow also minimizes heating of the material to avoid thermal degradation.
The Mill creates a relatively uniform particle size. The Screen only has an indirect effect on the particle size, because most particles do not escape the Grinding Chamber until they are small enough to flow with the air stream. However, impact with the Impeller throws some larger particles toward the Grinding Chamber exit. The Screen provides an upper limit of the size particles that can be thrown prematurely. Finer screens reduce the air-flow and consequently, the particle size the air can carry, as well as limiting the maximum particle size.
An optional Sample Feed Controller provides a uniform feed rate of material into the Mill. This significantly increases the uniformity of the particle size of the ground samples. It also makes sample addition more convenient and eliminates the possibility of Mill overloading.
The Cyclone Sample Mill is available in Direct Drive and Belt Drive versions. The Belt Drive version is recommended for almost all applications. The Direct Drive version can be used only for light duty application where uniform particle size distribution is not needed. It uses a .500 H.P. series wound universal motor with a speed of about 10,000 to 20,000 rpm depending on the load. The Belt Drive version is much quieter and has a higher grinding capacity. It rotates the Impeller at a relatively constant 12,600 rpm (10,500 for 50 Hz. Mills), using a ¾ HP totally enclosed induction motor. Additional general information about the Mill such as materials millable, sample feed into the Mill, initial and final particle sizes, etc. may be found in the color brochure of the Mill.