Application Primary crusher, to reduce the product corn size in a ratio 10....5....:1. Principle of working * The distance between the rolls is fixed in consideration of the requested final corn size and the teeth shape on the rolls (flat, angular, square, with a hook, ...), * The compression springs are calculated depending on the physical data of the product: the product is to be milled, a foreign particle (metal) separates the rolls, to avoid any mechanical damage to the roller mill. * Dust emission is very limited.