Home/Wheels
Wheels and components
Centrifugal Blower Wheel and Impeller Manufacturer
LONGWELL has made fan and blower parts in Yuyao, Ningbo since 1990 and ships to more than 30 countries. This page covers the component end of that business: the centrifugal blower wheel, the forward curve impeller, and the motor-plus-wheel assemblies most OEM buyers end up ordering. This is a project-based component line, so read what we actually supply before you send a drawing.
What we supply as a component, and what we supply as an assembly
Almost everything that leaves us against a wheel drawing is an assembly, not a bare wheel: an external-rotor motor with the impeller already fitted, balanced and run-tested, with or without a volute housing. Three levels are possible.
- Motorised impeller assembly (catalogue). Forward-curved wheels from 108 to 500 mm diameter on external-rotor motors in 072, 092, 102, 138, 188 and 218 mm rotor sizes, in AC, EC and DC. Single inlet, double inlet, or no housing at all if you supply your own scroll.
- Wheel and housing sub-assembly, no motor (project). Made to drawing. One example is a galvanised steel unit with a 143.8 mm wheel, 12.7 mm bore and a 221 x 217 x 212 mm envelope, spin-tested 8 hours at twice rated speed, 2,200 rpm, to prove the wheel does not shift on the hub.
- Loose blower wheel (project). Made to your drawing or to a sample you send. There is no catalogue of loose wheels and no stock, so every enquiry is quoted as a project.
On sourcing we would rather be plain. The wheels and blowers on this site are engineered and specified by LONGWELL, built to LONGWELL drawings in qualified partner plants, inspected to LONGWELL standards and shipped under our label. The exception is our cross-flow line, which runs in our own plant in Yuyao on our own moulds and impeller tooling, with blade insertion, roll riveting and balancing done in house.
Forward-curved versus backward-curved geometry
A forward curve impeller, also called a squirrel cage impeller, carries many shallow blades curved toward the direction of rotation, which moves a large volume of air at a small diameter and low tip speed, at the price of a rising power curve and lower peak efficiency. A backward-curved wheel uses fewer, deeper blades curved away from rotation, runs faster at the tip, holds efficiency across the duty range and will not overload the motor if system resistance drops. The forward-curved range is at forward curved squirrel cage blowers; the backward-curved motorized impeller range sits on longwellfans.com.
Materials
- Galvanised steel. The default for forward-curved wheels and scroll housings. Blades are inserted into the end discs and riveted or spot welded. Best value per unit, heaviest of the three.
- Aluminium. Mainly backward-curved wheels, roughly 225 to 800 mm across the internal-rotor and external-rotor families, with matched inlet rings from 225 to 710 mm. Lighter, better at high tip speed, higher material cost.
- Reinforced plastic. ABS with glass fibre, or reinforced AS, ABS and PP, injection moulded from about 65 to 476 mm. Double inlet plastic wheels are made as two halves and ultrasonically welded. Needs a mould, so it only pays back over volume.
- Stainless steel. Project only; we have drawn wheels in 316L for corrosive and wash-down duty.
Coating is a drawing item, not an assumption: state powder coat, epoxy, electro-galvanised or bare, plus colour.
Balancing grades
Treat the balancing grade as a number on the drawing. Our catalogue motorised assemblies are balanced to G6.3 to ISO 1940, and that is what the specification sheets carry. G2.5 is available when the drawing calls for it, and is the value used on the direct-driven commercial family. On project wheels an absolute residual unbalance is often clearer than a grade: one stainless wheel is drawn at under 120 mg at 960 rpm, with radial and axial run-out under 1.0 mm. Every assembly is dynamically balanced before the end-of-line bench, where earth continuity, dielectric withstand, insulation resistance and a run test are recorded.
Airflow, static pressure, voltage and control mode are enough for a first answer.
How a wheel is specified
A quotation needs all of these; a missing line costs a day of emails.
| Item | What to state | Why it matters |
|---|---|---|
| Outside diameter | mm over the blade tips | Sets the aerodynamic family |
| Wheel width | mm blade height | Scales airflow at a given diameter |
| Blade count and form | Blades, forward or backward curved | Pressure, noise and power |
| Bore and hub | Bore, keyway or flats, hub length, insert | Fit to your shaft or our rotor |
| Direction of rotation | CW or CCW seen from the inlet | A mirrored wheel is scrap |
| Balancing grade | G6.3, G2.5, or mg at a stated speed | Correction step and cost |
| Material and thickness | Galvanised steel, aluminium, plastic, stainless | Tooling route and unit price |
| Coating | Type and colour, or none | Often forgotten, always chargeable |
| Duty and speed | Airflow, static pressure, rpm, maximum speed | Checks the wheel is not overrun |
Airflow and pressure on our finished products are tested to the AMCA 210 method. Model-level curves and CAD for the assemblies sit on select.longwellfans.com, which is the quickest way to see whether a catalogue assembly already covers your duty before you pay for a custom wheel.
Tooling and MOQ
We do not publish one MOQ number, because the minimum follows the tooling.
- Your wheel matches an existing LONGWELL diameter and rotor size. No new tooling, lowest minimum, fastest route.
- Sheet metal wheel to your drawing. Blade and riveting tooling is comparatively cheap, so the minimum is moderate and the tooling charge is one-off.
- Injection moulded plastic wheel. The mould is the real cost. It only makes sense against a committed annual volume, and we will say so rather than take the order.
Samples of catalogue models ship in 1 to 3 days, production runs 15 to 30 days, warranty is 12 months. A loose wheel is a component and carries no approval of its own; our ISO 9001 certificate BMCQ0222448M and the product safety certificates cover the company and finished motorised products, with the scope listed on quality and certifications.
What to send us
- A 2D drawing or a 3D STEP file, or a physical sample with the bore and rotation marked.
- The duty point: airflow, static pressure and speed, plus the motor you intend to drive it with.
- Annual volume and the first order quantity, so the tooling decision is made on real numbers.
Send it to sales@longwellfans.com. We answer with a feasibility note first, catalogue assembly, drawing job or tooling job, and only then with a price. The project sequence is set out in the OEM process, and the other blower families are on the centrifugal blowers hub.
Request a quote with your wheel drawing or sample, and we will tell you plainly whether it is a component order or an assembly order.
Questions buyers ask
Do you sell loose blower wheels, or only complete blowers?
Both, but not on the same terms. Motor plus wheel assemblies are our normal business and are catalogue items in AC, EC and DC, with forward-curved wheels from 108 to 500 mm. Loose blower wheels and bare wheel-plus-housing sub-assemblies are made to drawing on a project basis only. There is no loose-wheel catalogue and no stock, so a loose wheel enquiry is quoted individually against your drawing or sample.
What balancing grade do you work to?
Catalogue motorised assemblies are balanced to G6.3 to ISO 1940, which is the value printed on the specification sheets. G2.5 is available as a drawing value and is used on the direct-driven commercial family. On project wheels we can work to an absolute residual unbalance instead of a grade, for example under 120 mg at 960 rpm with radial and axial run-out under 1.0 mm. State the grade or the limit on the drawing; we will not assume it.
What is the minimum order quantity for a custom blower wheel?
There is no single MOQ, because the minimum follows the tooling. If your wheel matches an existing LONGWELL diameter and rotor size, there is no new tooling and the minimum is low. A sheet metal wheel to your own drawing needs blade and riveting tooling, which is comparatively cheap, so the minimum is moderate with a one-off tooling charge. An injection moulded plastic wheel needs a mould, and only makes sense against a committed annual volume.
Which materials can you supply the wheel in?
Galvanised steel is the default for forward-curved wheels and scroll housings. Aluminium is used mainly for backward-curved wheels, roughly 225 to 800 mm, with matched inlet rings from 225 to 710 mm. Reinforced plastic covers ABS with glass fibre and reinforced AS, ABS and PP, injection moulded from about 65 to 476 mm, with double inlet wheels ultrasonically welded from two halves. Stainless steel, including 316L, is available on project orders for corrosive or wash-down duty.
What do I need to send to get a quotation?
A 2D drawing or 3D STEP file, or a physical sample with the bore and direction of rotation marked. Add the duty point (airflow, static pressure, speed), the motor you plan to drive it with, and your annual volume plus first order quantity. We reply with a feasibility note first, saying whether the part is a catalogue assembly, a drawing job or a tooling job, and only then with a price. Send it to sales@longwellfans.com.
Does a blower wheel come with CE or other certification?
No. A loose wheel is a component and carries no approval of its own. Our ISO 9001 certificate BMCQ0222448M covers the company, and the product safety certificates we hold apply to finished motorised products within their stated model scope. Air performance on finished products is tested to the AMCA 210 method. The full scope is listed on the quality and certifications page.
Where to go next
About LONGWELL: Ningbo Longwell Electric Technology Co., Ltd.
Ningbo Longwell Electric Technology Co., Ltd. (LONGWELL) has made blowers since 1990 in Yuyao, Ningbo. What we make, how we work, certificates and contact.
Read the pageBlower Factory and OEM Manufacturing Capability
What LONGWELL builds in its own Yuyao plant, what partner plants build to our drawings, and the drawing, balancing and test controls an auditor can check.
Read the pageBlower Selection and Sourcing Guides
How to specify a centrifugal blower, what drives its cost, impeller types, and how to audit a blower supplier in China.
Read the pageCentrifugal Air Blowers – Scroll and Volute Blower Range
LONGWELL scroll (volute) centrifugal air blowers: AC, EC, DC and gas lines, 77–355 mm, to 8,799 m³/h and 4,100 Pa. Compare the five lines.
Read the pageSend the duty point, get the model
Airflow, static pressure, voltage and control mode are enough to start — a drawing is better. An engineer answers, usually within one working day (GMT+8). Samples of catalogue models ship in 1–3 days.