Wet Fan Scrubber Unit

It has been developed in accordance with the industry’s requirements for high production rates and the high dust loads generated in South African coal mines, while requiring a minimum of maintenance.

The axial fan not only acts as an air mover but also as a scrubber and eliminates over  85% of the incoming dust load by encapsulating the dust particles within fine water droplets. These water droplets agglomerate under centrifugal force to the fan casing and most of the water and dust exit the scrubber at the first sump and drain. The balance of the dust, mist and air pass through a filter screen, where most of the remaining dust is removed. Finally, the mist and air passes over a mist eliminator, which removes all of the remaining mist encapsulated dust particles, leaving clean, water-free air to exit the unit.

The impeller is computer designed to give high volumetric efficiency with lower than average noise levels. It is hard chrome plated for long life and direct driven by an in-line water-cooled flameproof motor.

The motor has been specially designed and developed for this arduous high duty application by specialist electric motor manufacturers Transvaal Electric (Teco) of Johannesburg. As with all the equipment manufactured and supplied by CDC, development work on the motor is ongoing and a number of modifications have been made in recent years to further enhance the operating efficiency and reliability of the motor.

The screen is a result of intense development of different profiles to give maximum collection of the water dust particles with minimum pressure drop. Screens are currently manufactured from a multi-layer knitted stainless steel mesh construction, but new developments using random weave nylon mesh are also proving to be very promising.

The demister configuration was developed using complex fluid dynamics computer simulation programmes developed by the CSIR. The design gives very good water mist elimination at air velocities up to 12 m/sec.