GP-cone crusher parameters/cubicity Effect of: -stroke -reduction ratio -"width" of the feed material -application example -closed circuit for product shape

Stroke and flakiness index During the crushing stroke the material is crushed and its density increases. Bigger stroke gives higher density and bigger interparticular crushing action. It moves stones between others and cuts flaky grains into smaller and cuts corners of the grains improving their shape. GP300 MF, c.s.s. 20 mm, feed 5-50 mm ,Granodiorite

Crusher reduction ratio If the crusher setting is same with two different feed size, the reduction ratio is bigger with the coarser feed. Nowadays crushing ratio is calculated using either 80 or 50 % size on the crusher feed and discharge

The "width" of the feed material Wide feed fraction gives better shape for crushed aggregates than narrow one. Narrow feed is 25-55 and wide feed 12-55 mm. 12-15 mm fraction size is so called support fraction, it fills room between larger stones increasing the density and bringing more effective crushing stroke improving the product shape

Do we loose capacity? Not necessarily, finer feed gives also higher throughput

Closed circuit In the closed circuit feed change from narrow to wide fraction improves the shape of aggregates. Also the closed circuit increases crushing stages, same grains are crushed more times giving better shape. Smaller is the screen mesh size, better quality for the final product. GP100 MF, feed granite rock 25-55 mm c.s.s. 12 mm, screen mesh size 12 mm

Hur utnyttjar vi våra krossar för optimal kubisitet? Två tänkvärda diagram

Basic concepts for Closer look on Cubicity /Stroke relation NOMINAL STROKE, nSTR - Difference between CSS and OSS HORIZONTAL STROKE, hSTR - The horizontal movement of a point at mantle (picture 1.). RADIAL STROKE, rSTR - The radial movement of a point at mantle (the curve length). See picture 1. EFFECTIVE STROKE, eSTR - Effective stroke direction is against angle bisector between mantle mantle and concave. Effective stroke corresponds to the stroke which is possible to utilise after considering crusher dynamics. Effective stroke is less than or equal to nominal stroke (picture 2.). UTILISED STROKE, uSTR - Utilised stroke direction is against angle bisector between mantle and concave. Utilised stroke is same as real compression movement effected on aggregate. Compression movement is function of Cavity type, Eccentric shaft speed and Nominal stroke. Utilised stroke is always less than or equal to effective stroke. (picture 2.).

Choke zone concept CHOKE ZONE - Choke zone is the smallest crushing zone in closed side volume. Inter-particle breakage can occur only above choke zone. Choke zone controls the capacity of the crusher (picture 1). VOLUME RATIO OF CRUSHING ZONES, DV - The ratio of crushing zone volumes between two sequential zones.