Centrifugal blower - hot gas and plug build
Hot gas changes every assumption in a fan: the density you rated at, the steel you chose, the clearance you left and the oil you put in the bearing. This is the family we build when the gas is above what a standard blower tolerates.
Illustrative 3D render of a representative high temperature build, not a photograph of a shipped unit.
Ranges are the family envelope our own product pages publish. The order always confirms against an approved GA drawing with the duty point, speed and absorbed power for your installation.
Selection logic
Our own product page for this family publishes two numbers side by side, and we keep doing it on purpose: the standard table shows 100 to 15,000 CMH at 10 to 200 mmWC and the tiered build goes to 650 C. The first is what the shop quotes most often, the second is what the machine is capable of once material grade, clearance and bearing isolation are all designed around the temperature. Anyone who gives you one number without the other is guessing.
Three things change when the gas gets hot. Density falls, so the fan has to spin faster to make the same actual pressure – and pressure and power both track density at constant flow. Steel grows, so a cold-set clearance becomes a hot-seized one. And the bearing, which is a grease-filled precision part that hates heat, has to be moved, cooled or fed.
Build
Standard wheel, mild steel, high temperature grease, clearances nominal. Most dryer and process exhaust duty lands here.
Mild steel still works on the wheel to about 300-350 C; bearing pedestals move outboard, shaft is extended, seals upgrade.
Stainless SS 321 or SS 310 territory. Thermal growth is calculated part by part and cold clearances are recorded on the GA.
High temperature alloy selection, cooled or purged bearings, lagged casing, and a documented start-up sequence.
Duty fit
Kiln and cooler auxiliary fans, foundry and cupola fume, heat recovery transfer, curing and drying ovens, ceramics and glass, steel process off-gas. If the gas is above 200 C at the fan inlet, the standard centrifugal families stop being honest options and this tier table becomes the starting point.
Where the temperature is high and the dust is abrasive, the two failure modes stack: blade erosion accelerates and thermal growth closes the clearance. In that case we quote a plug arrangement – the wheel sits outside the hot, dirty stream and the gas is dragged through – and price the consumables up front.
A fan built for 450 C average and 620 C for twenty minutes a shift will be built wrong. Give us the profile and we design for it.
Range
| Parameter | High Temperature Plug Blower | Backward Inclined Blower | Industrial Exhauster Radial Shrouded Blower |
|---|---|---|---|
| Airflow | 100 to 15,000 CMH published; other sizes to the duty | 1,300 to 3,85,000 CMH | 400 to 1,50,000 CMH |
| Static pressure | 10 to 200 mmWC published; higher pressures by arrangement | 6 to 152 mmWC (published as 0.25 to 6 inWC) | 100 to 2,000 mmWC |
| Gas temperature | Tiers: to 150 C, 150-250, 250-350, 350-500, 500-650 C | Up to 250 C | Up to 200 C on this build; higher tiers by arrangement |
| Impeller / frame | Impeller 250 to 2,200 mm (range-wide) | Impeller 250 to 2,200 mm (range-wide) | Impeller 250 to 2,200 mm (range-wide) |
Blank cells mean the figure is not published for that family — ask us and we will confirm it against your duty.
Questions
Because they answer different questions. The standard table is the envelope we quote repeatedly without a special build. 650 C is the tiered capability once materials, clearances and bearing isolation are engineered for the temperature. We would rather show both than pick one.
Sometimes. Air cooling, extended shafts, purged seals and outboard pedestals come first because they do not put a water line next to a hot gas duct. Water-cooled components are a project decision, made on the drawing, not a default.
Yes, on the right tier and with the dust load understood. For boiler induced draft with heavy fly ash we usually pair the temperature tier with a radial or shrouded exhauster wheel and treat the casing liners as spares.
Airflow and pressure are always quoted at the actual gas density. Altitude, temperature and duct losses move the number — run it through the worksheet before you send it.
Straight-through air at low pressure: tube axial, vane axial and propeller builds in mild steel and aluminium.
High static efficiency, non-overloading power curve. The default wheel for clean and lightly loaded air at medium to high pressure.
Flat plates set at an angle: robust, tolerant of moderate dust, still efficient and still non-overloading.
Enquiry
Tell us the duty and the constraints. You get a selection, a build sheet and a price from the works — not a call centre.
