Multiple roll crushers of this kind particularly serve for crushing of mineral material to be crushed, more particularly for coal, ore, rock, natural stone, bauxite, marl, clay, oil sand or similar materials. These crushers are designed to crush the material arriving with a grain size of up to approx. 150 mm down to a grain size of usually <50 mm. Especially on crushing of coal, it is important that it is not or only a little compacted during the crushing procedure and that its inner structure is mainly maintained.
State of the art in technology according to DE 199 04 867 A1 is a device for crushing of mineral material with two crushing rolls, with the crushing procedure being executed between the crushing rolls and the walls of the crusher casing lying opposite to these rolls and provided with crushing devices. No crushing procedure runs between the two crushing walls with rotate in opposite direction.
Known from U.S. Pat. No. 5,547,136 is a mill in which the crushing procedure is executed between two rolls with cutting elements arranged at the circumference on helical lines. Underneath of the working gap, a fixed anvil extending in the longitudinal direction of the roll is arranged, with arched sieves being fastened to it on both sides adapted to the outer shape of the crushing rolls. Material that does not fall through the holes of the sieves is transported above these sieves back into the charge space. This mill mainly serves for fine crushing and/or grinding of waste material down to comparably small grain sizes.
An arrangement for crushing and cooling of an already relatively fine grain size material leaving from a calcining kiln is described in WO 94/21 381 AI, wherein the crusher has several roller-type crusher elements arranged side by side and at one level on a flying support. The rotational direction of the crusher rolls alternates from one roll to the other. The crusher rolls arranged on the same level fill the entire width of the dumping area of the inflow shaft, with one working gap each being left free between the crusher rolls, the size of said gap being determined by the desired grain size of the material to be calcined.
Known from U.S. Pat. No. 5,595,350 A is another roll-type crusher located at the end of a cooling facility, with four crusher rolls being arranged side by side, the first three of which, viewed from the feed side, rotate clockwise and wherein the fourth turns anti-clockwise opposite thereto. The material coming from the feed side and which has not yet fallen through the intermediate spaces between the first rolls is thus crushed in the gap between the third and the fourth roll. These four rolls are loaded differently during this process.