When designing and selecting the cross section shape of the spiral groove, the appropriate section should be selected according to the particle size of the feed. When sorting coarse-grained materials, the water flow on the section of the spiral groove should be thick, so that the coarse-grained gangue moves down the spiral groove at a faster speed under the action of the thick layer of water flow. In this process, under the action of inertial centrifugal force, the coarse-grained gangue moves to the outside of the spiral groove, while the upper layer of water also moves to the outside of the spiral groove, promoting the gangue particles to move to the outside of the spiral groove. The heavy minerals move in the inner side of the spiral groove, thus forming the zoning of light and heavy minerals on the cross section of the spiral groove. By adopting the spiral groove with concave section, thicker water flow can be obtained, which meets the requirement of sorting coarse grained materials. When selecting fine-grained materials, the section of the spiral groove is required to be gentle.
For coarse granular materials of -2mm, elliptical or parabolic cross section spiral grooves should be used. The ratio of the cross-sectional long axis of the study surface (i.e. the elliptic surface) to the short sleeve is 2, the length of the long sleeve is about 2/3 of the diameter of the spiral groove, and the long sleeve is arranged horizontally. The spiral groove with this section shape has better sorting effect on coarse grained materials. Better sorting effect can also be obtained by using spiral grooves with compound elliptic section.
The cross section spiral groove is also developed and produced abroad, the cross section shape of this spiral groove is changed from top to bottom, this spiral groove is used to separate the beach placer and other materials, the effect is good. The spiral chute with a cubic parabola section can obtain better sorting index when sorting slime.
