roll crushers

1. [img_assist|nid=12002|title=|desc=|link=none|align=right|width=280|height=146]Crushing rolls which break material by pressure continuously maintained between the faces of two revolving metal cylinders, with axes parallel to each other and separated by a space equal in size to that of the required finished product; used as fines crushers or for low reduction primary crushing of material of a friable and low-abrasive nature.
2. Sledging rolls employ a combination of impact, shear and pressure. They have at intervals round the rolls, rows of teeth of varying length which grip the rock and feed it into the crushing chamber, also acting as picks to break the larger lumps; the optimum type of feed is stratified friable rock.

Also: double-roll crushers