How much air does a hammer mill need to handle?

The amount of air that needs to pass through a hammer mill depends on the type of raw material and the fineness of grind. Finer grinding requires a larger quantity of air. Raw materials with a high fat/oil content also require a larger air quantity. In both cases, this has to do with temperature increase > cooling and to prevent the sieve plates from clogging up. With (very) coarse grinding only a small amount of air is needed. A rule of thumb is that the air speed through the perforation should be 4 to 5 m/s for fine grinding and/or fat/oil rich raw materials.