Krebs Water Only Cyclones

Water-Only cyclones are primarily used to "clean" (or wash) raw coal.

Krebs Water-Only cyclone for cleaning raw coal
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Water Only Cyclones Clean Coal

Water-Only Cyclones are used to “clean” or “wash” raw coal making a density separation. This cyclone design relies on the fact that the mineral matter is denser than coal. In this case the truncated cone bottom allows a hindered-settling bed to form which rejects lighter coal particles, while an elongated vortex finder lifts the light coal particles.

  • Finer coals must be cleaned in smaller diameter hydrocyclones, otherwise the drag forces in larger diameter hydrocyclones cause all the fine particles to report to "clean coal"
  • Pressure and feed solids affect the separating gravity
  • Can adjust separating density with apex size

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Krebs Products for Coal Processing

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A Characteristic of Design

A characteristic of this design in that some coal losses take place through the apex because larger coal particles are classified. This problem can be mitigated by using a 2-stage water-only hydrocyclone circuitry where primary losses are re-cleaned in secondary hydrocyclones and spirals. A much more efficient system results.

In some relatively easy applications, a nitride bonded silicon carbide ceramic apex insert along with upper liners of urethane or other elastomer is adequate to combat the wear.

  • There are several ceramic liner options to combat abrasion.
  • Pressure and feed solids affect the separating gravity.
  • Can adjust separating density with apex size
  • Compared to other water-based coal washing devices, the water-only cyclone offers a relatively compact design and provides very consistent performance.


water only cyclones

Performance and Benefits

Water-Only cyclones are designed to produce a low ash coal product and can handle feed particle 3/4” top-size

  • One can adjust separating density with pressure, apex size and vortex finder length
  • Compared to other water-based coal washing devices, the water-only cyclone offers a more compact design and provides relatively low separation densities
  • Many different liner materials are available
  • Shorter Vortex Finders ensure low separating densities
  • Long-Body ensures low separating densities
  • Performance simulations and technical support by FLSmidth Krebs


Note: Our D15LB-S-327 is specifically designed to clean 1MM top size coal. Combined with a second stage spiral circuit, the system can provide separation densities from 1.65 to 2.00 SG


Inquiry Request for Quote or Technical Information

Krebs Products for Coal Processing

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FLSmidth Krebs, Inc.  (Main Office)
5505 W. Gillette Rd.
Tucson, AZ 85743-9501 U.S.A.

Email: KREBS@flsmidth.com
Phone: +1-520-744-8200
Fax: +1-520-744-8300

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