Spirals are sorting devices which separate the materials according to their different densities. They can be used for a grain size range from approximately 0.04mm to 4mm, with a throughput per spiral of approximately 1t/h to 4t/h. If a higher throughput is required, two or three spirals can be combined to form one column. Several spiral columns can be joined to form banks of two, four, six or eight with one distributor for the inlets and collector chutes for the outlets. Different types of spirals for heavy, middling and light-density products.
Principle of operation
The slurry (content 10% to 40% solids depending on application) is fed into the spiral from the top. Spread on the spiral bottom, it moves down by gravity. A transverse flow is directed inwards on the sluice bottom or outside on the slurry surface is superimposed on the main flow. This combination results in a separation of the particles contained in the suspension, depending on their density. Particles with a lower specific gravity, such as wood, coal or organic matter, are concentrated in the outer areas of the flow. Particles with a higher specific gravity are transported towards the spiral axis.