A cyclone is a type of centrifugal separator that is used in the Chemical Process Industry. They are designed for the separation of gas/liquid and gas/solid mixtures, where the solid or liquid generally consists of fine particles (a dust/powder, or a mist).

The most commonly used design of the cyclone is the reverse-flow cyclone (see figure).

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        \___/    Top view


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The gas (mixture) enters the top chamber tangentially, and spirals down the apex of the conical section. The gas then moves upward in a smaller diameter spiral, and exits the cyclone through a central vertical pipe. Due to their inertia, the solid or liquid particles move radially to the walls, and slide down the walls to the bottom where the product is collected.

The advantages of the cyclone as a separation device are that it is a relatively simple, cheap construction, and that it can be designed for use at high temperatures and pressures. Using a cyclone, solid particles as small as 5 μm can be separated from a gas stream. Smaller particles can be separated when agglomeration occurs (e.g. liquids). Compared to filter separation, the cyclone also has less pressure drop, which may be an economical consideration.