Crushers corrugated

Smooth jaws produce more numerous flaky pieces than corrugated jaws. Curved jaws produce less fines but more numerous flaky particles. Crusher speed has little effect. The presence of material too small to be crushed has a deleterious effect on the shape of products. Secondary crushers with a small reduction ratio can improve the shape of primaiy crushed material, but secondaiy crushers are not inherently different from primaiy crushers. Slotted screens can remove flaky particles from the product. Impact crushers produce fewer flaky particles than any other type. 

The so-called drug mill consists of a cone revolving within another cone (or both surfaces may be curved) without eccentric motion, wherein it differs from the gyratory crusher. These surfaces usually have corrugations on them so that comminution is mainly a matter of shredding and tearing rather than of crushing or abrasion. 

Roll crushers are size reduction devices that shear (or compress) the material that is to be reduced in size. The surfaces used can take the form of a rotating roll and a stationary anvil, or two equal-speed rolls rotating in opposite directions. The surfaces of the rolls can be smooth, corrugated, or toothed. The particular design of the teeth and corrugations is critical in keeping the production of lines and dust to a minimum (Roman, 1967). 

Roll crushers. In Fig. 14.5-3b a typical smooth roll crusher is shown. The rolls are rotated toward each other at the same or different speeds. Wear of the rolls is a serious problem. The reduction ratio varies from about 4 1 to 2.5 1. Single rolls are often used, rotating against a fixed surface, and corrugated and toothed rolls are also used. Many food products that are not hard materials, such as flour, soybeans, and starch, are ground on rolls. 

Roll crushers are used for the primary reduction of medium-hard moist and abrasive materials such as marl, shale and clay (Fig. 9). The feed is subjected to compressive and shearing action between a pair of counter-rotating rolls, which may be either smooth or corrugated or provided with tooth-like projections. The teeth give better bite to the feed and concentrate the action of the crushing force, enabling large and compact pieces of rock to be split. 

---