Editing Cyclonic separation (section)

== Operation ==
A high-speed rotating (air)flow is established within a cylindrical or [[conical]] container called a cyclone. Air flows in a [[Helix|helical]] pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end before exiting the cyclone in a straight stream through the center of the cyclone and out the top. Larger (denser) particles in the rotating stream have too much inertia to follow the tight curve of the stream, and thus strike the outside wall, then fall to the bottom of the cyclone where they can be removed. In a conical system, as the rotating flow moves towards the narrow end of the cyclone, the rotational radius of the stream is reduced, thus separating smaller and smaller particles. The cyclone geometry, together with [[volumetric flow rate]], defines the ''cut point'' of the cyclone. This is the size of particle that will be removed from the stream with a 50% efficiency.  Particles larger than the cut point will be removed with a greater efficiency, and smaller particles with a lower efficiency as they separate with more difficulty or can be subject to re-entrainment when the air vortex reverses direction to move in direction of the outlet.<ref>{{cite web | url=https://www.powderprocess.net/Solid_gas_separation.html | title=Solid Gas separation methods - Industrial dust collectors - cyclone - scrubbers - filtration - PowderProcess.net}}</ref>

[[File:Vertical-cyclone.jpg|thumb|200px|Airflow diagram for Aerodyne cyclone in standard vertical position.  Secondary air flow is injected to reduce wall abrasion.]]

[[File:Horizontal-cyclone.jpg|thumb|400px|Airflow diagram for Aerodyne cyclone in horizontal position, an alternate design.  Secondary air flow is injected to reduce wall abrasion, and to help move collected particulates to hopper for extraction.]]

An alternative cyclone design uses a secondary air flow within the cyclone to keep the collected particles from striking the walls, to protect them from abrasion.  The primary air flow containing the particulates enters from the bottom of the cyclone and is forced into spiral rotation by stationary spinner vanes.  The secondary air flow enters from the top of the cyclone and moves downward toward the bottom, intercepting the particulate from the primary air.  The secondary air flow also allows the collector to optionally be mounted horizontally, because it pushes the particulate toward the collection area, and does not rely solely on gravity to perform this function.