My duty carries sparks and hot embers. Is your fan spark-resistant?
Yes. We build spark-resistant construction to AMCA 99, which defines three types. Type A puts all parts in the airstream in non-ferrous material; Type B uses a non-ferrous rub ring and non-ferrous parts across the shaft opening; Type C is an aligned construction that mechanically prevents a rotating ferrous part from touching a stationary one. Type B is our default for weld and grind fume, and Type A is used where the combustible-dust case is severe. On ducts that carry live embers from welding or an EAF we also fit a spark arrestor upstream of the filter, because the real fire risk is an ember reaching the filter media, not the fan itself. We select the type to your stated ignition risk and mark it on the GA drawing and nameplate.
We grind aluminium and magnesium. Is that a combustible-dust case, and are you ATEX-rated for it?
Yes, grinding aluminium, magnesium and titanium produces combustible metal dust, and it is a genuine explosion hazard suspended in the duct. For that duty we self-declare ATEX Zone 22 per 2014/34/EU, Category 3D, combined with spark-resistant construction so both the ember and the dust-explosion cases are covered by one build. The configuration uses a non-sparking impeller, bronze rub rings, bonded earthing throughout, anti-static coatings and T-class bearing-temperature control. To be precise, that is a self-declaration of conformity, not a third-party certification; our only third-party certification is ISO 9001:2015. Zone 21 (Category 2D) is available on application via a Notified-Body partner. Note that water is the wrong extinguishant for burning metal fines, so the collector and suppression design matter as much as the fan.
Should the fan sit on the clean side or the dirty side of the filter?
Clean side is the common position and the easier duty. Downstream of the baghouse or cartridge collector the inlet loading is low, so wear is minimal and the design focus is spark resistance, curve stability across filter loading, and noise. Dirty side, and EAF primary in particular, is much harder: the fan handles raw fume ahead of the filter at a much heavier dust load, hot and abrasive, so it gets the full wear package and a spark-resistant, heat-rated build. Tell us where the fan sits and we build to that position; on dirty-side duty we assume the worst of your loading and temperature data, not the average.
How hot can the fan run on direct EAF extraction?
On EAF primary or fourth-hole extraction the raw off-gas leaves the furnace far above any fan's limit, so the system takes it off a water-cooled duct that drops the gas into our window before it reaches the fan. Rated that way, the fan handles up to 600 °C at the ceiling of the envelope. We upgrade the casing to IS 2062 or 16Mo3, size the shaft for thermal growth, and select bearings for a sustained 80 to 100 °C housing temperature. The build is engineered to your stated gas temperature and excursion case downstream of the cooling duct, not a generic rating.
How do you stop fine metallic dust from eroding and unbalancing the wheel?
Weld fume and grinding grit are fine, hard and dense, so uneven erosion throws a curved wheel out of balance before it ever wears through. We default to a radial-tipped wheel that rejects dust from the blade root rather than packing it in, add chrome-carbide hard-facing on the blade leading edges for severe grit, and bolt in AR400 wear plates at the volute throat and outlet with hinged access doors so they can be replaced in place, not cut out and re-welded. The wear package is sized to your dirty-side loading, and on clean-side duty after the filter it is usually not needed at all.
The duct run is long and the filter pressure drop keeps climbing. How do you size for that?
Fume systems combine a long capture-to-stack duct run with a filter whose pressure drop climbs as media loads between pulse-clean cycles, so the system resistance is both high and moving. We size the fan to span the clean-filter point and the fully-loaded point without running at a control limit, with a minimum 20 percent flow margin at the clean condition and the curve extending through the loaded condition. VFD control is our default so the fan holds hood capture velocity as the filter fills, rather than coasting down and letting fume drift out of the hood. We then verify the curve on the 200 HP VFD test rig before dispatch.
We're a pollution-control OEM. Can you supply just the fan as a sub-package?
Yes. We supply fume fans separately to baghouse manufacturers, cartridge-collector OEMs and stack or scrubber integrators. You specify the duty and the integration interface — flange dimensions, mounting orientation, spark-resistant type, ATEX scope, electrical interface and control protocol — and we document it up front and deliver the fan ready to mate. The engineering is identical to a direct-buyer fan; only the integration interface and who buys it differ. Fume extraction is our strongest application by track record, with 101 customer duties across iron and steel, foundry, fabrication and pollution-control OEMs.
Do you performance-test before dispatch, and what standards actually apply?
Yes. Every fan is performance-tested in-house to the AMCA 210 / ISO 5801 method on our 200 HP VFD test rig, and dynamically balanced to ISO 21940 G6.3 as standard, with G2.5 or G1.0 on application. To be precise about the claims: that is testing to the AMCA 210 method in-house, not an AMCA certification; spark-resistant construction is built to AMCA 99; and CE and ATEX are self-declared per the relevant EU directives, not third-party certified. Our only third-party certification is ISO 9001:2015. For a standard clean-side fume fan the offer turns around in 3 to 5 working days and order-to-dispatch runs roughly 9 to 14 weeks; a spark-resistant ATEX or EAF-heat build adds file prep and runs about 12 to 16 weeks. The test and FAT take about a week and are customer-witnessed on request.
