Continuing with our discussion of cyclone technology we will now derive the hydrocyclone and desander. The purpose is to clarify the terminology of all these devices.

Hydrocyclones

The hydrocyclone is a contraction of the term “hydraulic cyclone” and signifies that the carrying fluid phase is a liquid. While the use is predominantly in aqueous systems with water as the carrying fluid, hydrocyclones can be used on any liquid. I’ve ran them on glycol, diesel, fruit juice, and picante sauce to name a few. The hydrocyclone is a subset of the cyclone unit process – it has the same features and benefits as previously discussed.

Hydrocyclone History

• The hydrocyclone is considered a mineral processing device – and that is where it still finds predominant use and where most research is published (same goes for flotation!)
• First patented in 1891
• Significant developments post-WWII to replace rake and screw classifiers
• Primary uses are closed circuit grinding and solids density classification
• Operates with open (atmospheric) underflow and overflow – this operation allows a central (vacuum) air core
• 1000+ journal and conference papers on mineral processing hydrocyclones
• Key authors: Bradley, Kelsall, Svarovsky, Trawinski, Plitt, Lynch-Rao, Rietema, Fahlstrom, Arterburn, Rajamani, Miller, etc.

Graphic below shows flow patterns within a hydrocyclone (courtesy of FLSmidth Krebs).