EVHA member, Hamster Cleaning of Belgium has posted some remarkable footage of cleaning a car park extract duct.
The videoclip really helps to illustrate the effect of a powerful duct cleaning extractor unit along with a rotary brush. The powered brush dislodges the dust into the air stream created by the cleaner's powerful, high volume vacuum machine for collection on a filter system.
It also shows how a skilled operator can 'walk' the brush from side to side in a flat-wide duct with stiffener bars. Careful manipulation of the brush rotation and working section-by-section provides complete coverage