Pioneers in Compressed Air Drying and Filtering. Quality at a Fair Price. 

Outlet wet hot air from rotary dryers can entrain fine particles from the product being dried, resulting in atmospheric pollution and loss of product. To reduce the carry-over of product dryers, lower drying velocities can be designed, but at an increase in capital cost.

Our standard range of dryers are designed for low carry-over with double horizontal cyclones at the outlet to collect entrained particles and reintroduce them to dry product at outlet.

Essentially the arrangement of compact cyclones consists or two or more horizontal cyclonic cells in parallel, discharging the collected dust into a common hopper.

In some drying applications the product might be too fine for collection in our cyclones, in which case bag filters or wet scrubbers need to be installed.

A brief summary of the various options follows further down the page.

High Efficiency Multiple Cyclones for Dust Collection

  • Twin high efficiency cyclones for dryer exhaust dust collection.
  • Multiple cells for improved collection efficiency.
  • Two-stage separation reduces re-intrainment of collected dust.
  • Compact design mounted on back end of rotary dryer.
  • Rotary gate or double flap valve for dust extraction.

Cyclones only:
  • Cyclonic collection is the first choice because of operational simplicity.
  • Our cyclones are of the twin Feifel design, and are usually horizontally mounted, resulting in a more compact design.
  • A constant air flow is maintained through the dryer.
  • A small quantity of dust containing silica is discharged into the atmosphere; hazardous pollution and loss of some product.
  • Little can go wrong with the cyclones which necessitates the stopping of production.
Bag Filter only:
  • Virtually all dust, 99.5 - 99.9% of product and silica is collected, no pollution or loss of product.
  • Flow of air through the dryer slowly diminshes, plant has to stop production for cleaning or replacing of bags.
  • More chance of or breakdown or mishaps and complete loss of production.
  • As the superfine dust, which carries proprtionally more silica due to its lower density is now all handled downstream, dust control could be needed to suppress the mainly silica dust, which will escape from the bucket elevator and other handling points, more so than in the case of cyclones only.
Cyclones and bag filter:
  • Virtually complete collection, approximately 99.5% of all the superfine dust, most of the time.
  • Should the baf filter need maintenance, or shoud it be out of commission for some times, the plant reverts back temporarily to the 'cyclone only' situation, but production will be maintained, and the air flow through the dryer will not be affected, thus maintaining optimum design conditions.
  • As the superfines contain silica, they should be disposed of safely, resulting in a small product loss.