ID fans handle the most punishing duty in any gas-handling system: hot flue gas, fly ash, abrasive particulate, acid condensate. They run continuously — and when they fail, the boiler or kiln upstream stops. We build ID fans across cement, power, iron & steel, chemicals and process plants, from package boilers to large utility units, across the full envelope below.
A sample of units we've engineered, built and dispatched — each to a customer's duty point. Customer names and identifying marks are withheld. Click any photo to enlarge.
An Induced Draft fan sits downstream of the heat source: pulling flue gas out, holding the furnace under negative pressure, and pushing it through the pollution-control train (ESP, bag filter, scrubber) to the stack.
Enough gas to hold target furnace draft — typically −5 to −25 mmWC at the boiler outlet.
Through the whole system resistance — ducting, filtration, economizer, stack — which can total 250–2,000 mmWC.
The gas itself — 150–400 °C continuous (to 500 °C for kilns), laden with fly ash, sometimes with acid dew-point risk.
Hot gas + abrasive particulate + corrosive condensate drive the three things that destroy ID fans. Design for them, and the fan runs 10+ years between major overhauls. Design only for performance, and it fails in 18–30 months.
Fly-ash particles strike the blades at >50 m/s. Material loss throws the rotor out of balance and cracks the blade root over time.
How we engineer it outHard-faced (chrome-carbide) leading edges and impeller geometry chosen to minimise the particle impact angle.
Particle-laden gas scours the casing at the volute throat and outlet — the highest-velocity zones.
How we engineer it outReplaceable, bolted-in AR wear plates on the high-wear zones, with access doors for site replacement — no dismantling the fan.
Below the SO₃ dew point (~120–150 °C) sulfuric acid condenses on the casing wall and eats it.
How we engineer it outInsulation and heat tracing to hold the wall above dew point, plus corrosion-resistant metallurgy on the wetted surfaces.
We don't sell a catalogue near-fit. The fan is engineered to your gas, temperature, dust load and operating point.
No catalogue fan forced onto your spec. Your operating point is engineered onto the best-efficiency region of the selected wheel — then verified on the 200 HP VFD test rig before dispatch.
| Parameter | Standard | On application |
|---|---|---|
| Volume flow | up to 2,25,000 CMH | higher on enquiry |
| Static pressure | up to 2,000 mmWC | higher on enquiry |
| Continuous gas temperature | up to 500 °C | higher with refractory lining + special metallurgy |
| Inlet particulate loading | heavy inlet loading | higher with enhanced wear protection |
| Drive power | up to 425 HP | higher with custom motor sourcing |
| Speed | 600–1,800 RPM typical | per duty + sound limits |
| Balance quality | ISO 21940 G6.3 | G2.5 / G1.0 on application |
| Bearing life (design target) | L10h ≥ 40,000 h continuous | longer L10 on application |
The envelope above covers the great majority of industrial ID-fan duty. For duty beyond it, we engineer to spec and quote on enquiry. Inlet dust loading is duty-dependent — heavy on raw-gas / pre-precipitator and booster-ID service; light on clean-side ID downstream of an ESP or bag filter.
The same engineering language carries from your enquiry to the GA drawing to the nameplate — expressed in the standard AMCA conventions.
| Specification field | Options |
|---|---|
| Arrangement (AMCA 99) | Arr. 1 (overhung, fan bearings) / Arr. 4 (direct, motor on base) / Arr. 8 (overhung on common base) / Arr. 9 (overhung, motor side) / Arr. 10 (overhung, motor inside base) — selected by drive, access and temperature. |
| Width / inlet | SWSI (single width, single inlet) default for ID duty; DWDI (double width, double inlet) for high flow at moderate pressure. |
| Wheel type | Radial-tipped backward-curved (default, best efficiency) / straight-radial (when fly-ash buildup dominates) / backward-curved (clean-gas, high-efficiency duty). |
| Class (by pressure / outlet velocity) | Class I / II / III selected from the duty point on the pressure-vs-outlet-velocity limits; higher class = heavier construction for higher pressure and tip speed. |
| Materials of construction | MS (standard) / IS 2062 casing with AR400 bolted wear plates / hard-faced (chrome carbide) or 4140 wheel for abrasion / 316L, Corten, Hastelloy or Inconel for acid dew-point and corrosive gas. |
| Drive | Direct-coupled / V-belt / VFD (default for variable-draft control). Drive up to 425 HP across the envelope; speed typically 600-1,800 RPM. |
| Discharge & rotation (AMCA orientation) | Rotation CW or CCW (viewed from drive side) with discharge angle per AMCA — e.g. TH/BH/UB/DB — set to match your duct take-off and installed footprint. |
| Accessories & high-temp scope | Inlet vane damper or VFD control; fabric or metal expansion joints (thermal growth to ~25 mm at 400 °C); bolted-in AR wear plates and access doors; shaft cooling disc (standard above 400 °C); casing insulation and heat tracing for acid dew-point service; drain and inspection doors. |
Every job's performance is verified at our works on the 200 HP VFD test rig, to the IS 4894 / ISO 5801 / AMCA 210 method, before dispatch.
Sinter-plant ID, blast-furnace gas cleaning, reheating-furnace flue gas.
Kiln ID, pre-heater fans, raw-mill ID.
Boiler ID (utility + cogen), ESP-downstream fans.
Process-boiler ID, RTO / RCO downstream fans.
Cupola ID, induction-furnace fume, heat-treatment ID.
Drying-furnace ID for spray driers and roasting lines.
Solvent-recovery and drying-furnace ID fans.
45 application/duty types engineered. Tell us yours.
What our marks mean, in the words that survive an audit.
Tested to the IS 4894 / ISO 5801 / AMCA 210 method, in-house on our 200 HP VFD rig. Tested-to-method — not AMCA-certified.
ISO 9001:2015 — third-party certified. Our only third-party certification.
Self-declared per 2006/42/EC + 2014/35/EU. A self-declaration, not a notified-body certificate.
Self-declared, Zone 2/22, Category 3, per 2014/34/EU, where the area classification calls for it.
Designed and built to API 673 as project-specific scope.
ASME Sec IX qualified welders + WPS for every joint.
ISO 21940 — G6.3 minimum, G2.5 / G1.0 on application.
ISO 14694 fan-specific limits; ISO 20816 general evaluation method.
| Stage | Standard duty | CE / ATEX / API / AMCA |
|---|---|---|
| Offer / quotation | 3 working days | 5 to 7 working days |
| GA drawing for approval | 3 days from customer PO | 5 to 7 days from customer PO |
| Manufacture + balance + paint | 2 to 3 weeks from PO + PI + approved GAD | 4 to 5 weeks from PO + PI + approved GAD |
| Performance test + witnessed FAT | ~1 week | ~1 week |
| Order-to-dispatch (total) | 4 to 6 weeks | 7 – 9 weeks |
Shutdown-driven replacements: we have shipped fans within 3 weeks of a clean PO. Tell us your shutdown window and we commit to a dated plan.
The same engineering, viewed three ways — by fan family, by duty, and by industry. Follow the cross-references.
An ID fan handles hot gas, and hot gas is thin. Quote the fan on normal cubic metres and it will be too small — because a fan moves volume, and the volume at the fan inlet is not the volume in the combustion calculation.
At 200 °C the fan must be 1.73 times the normal-condition volume. Miss that and the fan is undersized by nearly three-quarters — which is the single most common reason an ID fan "cannot make its duty" on a plant where nothing is actually broken.
The density cuts the other way on power: thin gas is easier to move, so shaft power falls with it — but a fan that must also start on cold gas sees the cold-density power, and the motor has to be sized for that. Tell us the cold start condition as well as the running one.
Take the flue gas mass flow or Nm³/h from your boiler maker's own heat-and-mass balance. Fuel, excess air and ash vary by plant, and that figure is theirs to state — the correction above is what turns it into a fan.
Flow, static, gas temperature, application — or attach a spec, GA drawing or a multi-fan schedule. Engineer to engineer.
ISO 9001:2015 quality system · performance-tested to IS 4894 / ISO 5801 / AMCA 210 method · witnessed FAT on request, at no cost.
*For our standard range, additional days required for special projects
