Centrifugal fans

A centrifugal fan turns shaft power into pressure more efficiently than any other arrangement, which is why it still does most of the heavy lifting in industrial ventilation forty years after everyone predicted it would be replaced. Air enters along the shaft, is thrown outward by the impeller, and leaves the scroll at right angles to where it came in — and that change of direction is what buys you pressure.

We build them in nine casing sizes with three impeller families. Backward-curved blades for anything where efficiency matters and the air is clean; forward-curved where you need volume from a small casing and can accept the steeper power curve; and open paddle for dust, swarf, shavings and anything else that would clog a closed impeller within a month.

Every casing is welded rather than bolted from pressed panels. It costs more and it is the reason our fans do not develop the low-frequency drumming that a panel casing picks up after a few thousand hours. Impellers are dynamically balanced to ISO 21940 grade G2.5 as standard and G1.0 on request, which matters more than most specifications admit: a fan that is out of balance destroys its own bearings and then the building steel it is bolted to.