The Backward-Flat Plate family is the high-flow specialist: flat steel plate blades set backward-inclined make a strong, large-diameter wheel that moves big volumes of air while still developing medium-to-high pressure. We build Backward-Flat Plate fans for large industrial ventilation, flue and process-gas handling, drying, deep-tank aeration and digester/biogas duty across chemicals, pharma, food, water & wastewater and biogas plants — single-width up to the large double-width rotor, across the full envelope below.
Backward-Flat Plate wheels use flat (laminar) plate blades that lean backward — straight plates rather than the shaped curve of the Backward-Curved Plate family. The flat plate makes a strong, large-diameter rotor that handles big airflows; the backward lean keeps the power curve non-overloading. It trades a little efficiency for size and high-volume capability.
High airflow is the driver. The large double-width wheel reaches the biggest flows in the range — engineered to ~2,00,000 CMH within our publishable envelope, larger on enquiry.
Medium-to-high static at that volume — per-model up to ~1,400 mmWC on the plate wheels, so the fan covers flue/process-gas and large drying duty other backward fans cannot reach at size.
Light dust within the family's design gate, and a flat-plate blade that is straightforward to wear-protect, repair and field-service on a large rotor — not a thin shaped blade that erodes.
The Backward-Flat Plate family sits in a deliberate spot in the range: more volume than the Backward-Curved Plate workhorse, more efficiency than a radial. Pick it for the three reasons below — and accept the matching trade-offs honestly, rather than forcing the wrong wheel onto a large duty.
Large ventilation, flue-gas and drying duties need big volumes of air — beyond what a compact curved-plate wheel moves without over-speeding or over-sizing.
How we engineer it outA flat-plate large-diameter rotor — single-width on the plate wheels, the large double-width wheel for the largest flows — sized on the best-efficiency region for the volume, not the nearest box.
The duty still needs real pressure — flue/process gas and deep drying systems — but inflated catalogue pressure points fail a basic motor-power check.
How we engineer it outThe plate wheels run a 140 m/s Class 3-4 plate build to ~1,400 mmWC per model; the figure is the software-validated structural ceiling, sanity-checked against absorbed power — not a brochure number.
High-volume drying and flue-gas duty runs hot, and a large rotor has to be balanced, transported and serviced — where reliability is actually won or lost.
How we engineer it outHighest served gas temperature in the backward range (a 500 °C job), shaft cooling above ~150 °C, and split/sectioned casing with a rotor-handling SOP and witnessed run-test on large wheels.
We don't sell a catalogue near-fit. The fan is engineered to your flow, pressure, gas temperature, dust load and operating point — and the large rotor is designed for how it will be balanced, shipped and serviced.
No catalogue fan forced onto your spec. Your high-flow operating point is engineered onto the best-efficiency region of the selected wheel — then verified on the 200 HP VFD test rig (AMCA 210 / ISO 5801 method) and dynamically balanced before dispatch. On a large rotor, the stated balance grade and a witnessed run-test are exactly where reliability is won.
| Parameter | Standard | On application |
|---|---|---|
| Volume flow | up to 2,00,000 CMH | larger on enquiry (the double-width rotor scales further) |
| Static pressure | up to ~1,400 mmWC per model | higher on enquiry |
| Gas / air temperature | up to 600 °C with HT construction | served to 500 °C — confirmed on enquiry |
| Dust tolerance | Light dust only (design gate) | heavier abrasive dust → step to the Radial family |
| Drive power | up to 400 HP | higher with custom motor sourcing |
| Static efficiency | High for the flow class (exact figures shared with your enquiry) | wheel selected near best efficiency for the duty |
| Balance quality | ISO 21940 G6.3 | G2.5 / G1.0 on application (large rotors) |
| Bearing life (design target) | L10h ≥ 40,000 h continuous | longer L10 on application |
The envelope above sits inside Jitamitra's publishable ceiling (2,00,000 CMH / 2,000 mmWC / 400 HP / 600 °C); the Backward-Flat Plate family is the high-flow family within it, peaking on static around ~1,400 mmWC per model rather than the very top of the pressure range. Dust tolerance is the design gate — light dust only; once the dust becomes more than light, the Radial family is the right family. For duty outside the envelope we engineer to spec and quote on enquiry.
The same engineering language carries from your enquiry to the GA drawing to the nameplate — expressed in the standard AMCA conventions, so the build is unambiguous.
| Specification field | Options |
|---|---|
| Arrangement (AMCA 99) | Arr. 1 (overhung, fan bearings) / Arr. 3 (between bearings, common on large DWDI rotors) / Arr. 8 (overhung on common base) / Arr. 9 (overhung, motor side) — selected by drive, rotor size, access and temperature. |
| Width / inlet | SWSI (single width, single inlet) on most single-width plate wheels; DWDI (double width, double inlet) on the largest plate wheel and the large double-width rotor for high volume in a compact height. |
| Wheel type | Flat (laminar) backward-inclined plate — four single-width plate wheels and a large double-width flat-blade wheel for the highest flows. Backward lean = non-overloading characteristic. |
| Class (by pressure / outlet velocity) | Class 3-4 plate build (single-width, 140 m/s tip) / large low-stress build (double-width, 120 m/s tip), 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) / SS304 / SS316 full or airstream / Corten or duplex for corrosive flue-gas and drying duty / FRP (F) for corrosive light-duty air / wear-plated (WP) leading edges and replaceable liners for light-dust service. |
| Construction suffix | HT (high-temperature: heat scope + shaft cooling disc) / SR (spark-resistant: AMCA 99 Type A/B/C, ATEX self-declared) / F (FRP airstream) / WP (wear-plated). Combined per duty — e.g. HT for hot drying gas, SR for solvent / combustible-dust exhaust. |
| Drive | Direct-coupled / V-belt / VFD with shaft-earthing ring (default for variable-volume control). Drive up to 400 HP across the envelope; split SNL plummer-block bearings on large rotors for maintainability. |
| Accessories & large-rotor scope | Inlet box and inlet/outlet dampers; in-cone IGV; flexible connectors and AV mounts; inlet/outlet silencers; shaft cooling disc above ~150 °C; wear protection and replaceable liners; spark-resistant build where the zone requires it; split/sectioned casing and a rotor-handling SOP for fans that exceed container or transport limits. |
Every job's performance is verified at our works on the 200 HP VFD test rig, to the AMCA 210 / ISO 5801 method, before dispatch.
Flue and process-gas handling, large drying systems, corrosive-airstream ventilation.
Large cleanroom / pharma AHU, spray and fluid-bed drying exhaust.
Spray-drier and flash-drying air, large process and building ventilation.
Deep-tank aeration, sludge drying and handling exhaust.
Digester / biogas booster and process-gas handling.
Hot drying and flue-gas duty — the family's highest served temperature.
High-flow process and ventilation air on power-adjacent plants.
339 Backward-Flat Plate builds delivered. Tell us your duty.
What our marks mean, in the words that survive an audit.
Tested to the AMCA 210 / ISO 5801 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 (Module A). 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 20816 evaluation; ISO 14694 for fan-specific limits.
| Stage | Standard duty | API-673 / engineered |
|---|---|---|
| Offer / quotation | 3 working days — always | 7–10 working days |
| GA drawing for approval | 2–3 weeks from PO | 3–4 weeks from PO |
| Manufacture + balance + paint | 6–10 weeks | 10–14 weeks |
| Performance test + witnessed FAT | ~1 week | 1–2 weeks |
| Order-to-dispatch (total) | 9–14 weeks | 14–20 weeks |
Shutdown-driven replacements: we have shipped fans within 6 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.
No model numbers needed. Give us the operating conditions — flow, static, gas temperature, composition, particulate, and any tender standard — and our application engineers size the fan and quote it. Attach a spec or GA if you have one.
+91 90110 09155 · mihir.jitamitra@gmail.com