I am very pedantic when it comes to terminology applied to cyclonic equipment. This is because there are too many sloppy salesman using poor vernacular and overselling the equipment, or selling the wrong equipment – the result is a bad name for cyclones. Without proper definitions we end up making vague statements that confuse everyone (like the photo above).
As previously discussed the desander is a subset of the mineral processing hydrocyclone. Technically the desander is a “flooded-core hydrocyclone”, since the encapsulation of the underflow prevents formation of an air-core.
The desander and hydrocyclone share essentially the same components. The following graphic identifies the main components and flow streams around both of these devices (photo on left courtesy of FLSmidth Krebs).