High-Temperature Centrifugal Blower Manufacturer: Furnace, Kiln and Oven Duties Up to 800 °C

NextAir Systems, Faridabad, India. Last reviewed October 2026.

A blower handling gas at 600 °C is a different machine from one handling air at 20 °C, even if the two look alike on a drawing. At 600 °C the gas has a third of the density, so the volume to be moved is nearly three times as large for the same mass. Meanwhile the wheel and shaft expand, bearings sit beside a hot casing, and materials lose strength. All of it is predictable, and all of it has to be designed in.

NextAir builds high-temperature centrifugal blowers for furnaces up to 800 °C, kilns up to 650 °C and ovens up to 500 °C, in our own factory, with the materials, bearing cooling and speed limit engineered for the duty. This page explains what the temperature changes.

At a glance

• Our high-temperature range covers furnaces up to 800 °C, kilns up to 650 °C and ovens up to 500 °C.
• At 600 °C, dry air has 34% of its 20 °C density, so 1,000 normal-condition cubic metres per hour of gas occupy 3,197 actual m³/h, and the blower must be sized for the larger volume.
• A steel wheel one metre in diameter grows by roughly 9.4 mm between 20 and 800 °C, using a typical expansion coefficient of 12 µm/m·K, which clearances and fits must allow for.
• At high temperature, the materials, bearing cooling and speed limit are engineered for the duty, and the motor and drive are bought-out items matched to each blower.

Hot gas is thin gas

Gas density falls in proportion to absolute temperature. A blower is a volume machine, so the pressure it develops and the power it absorbs scale with density at the fan inlet, while the volume it must move for a given mass flow rises. The table shows dry air density, the actual flow occupied by 1,000 normal cubic metres per hour of gas, and the density as a share of the 20 °C value, calculated from the ideal gas law. The last column is the thermal growth of a one-metre steel wheel, from a typical expansion coefficient of 12 µm/m·K.

At 800 °C the same mass flow needs about 3.7 times the volume, so the blower is much larger than a cold one for the same process, while the pressure it develops at a given speed falls to a quarter. That is why the selection must use the gas condition at the inlet, as set out in gas temperature, altitude and density correction. Gas composition shifts the figure too, as in gas composition and density.

Cold start is the worst case for the motor

Density is highest when the blower starts cold, so the shaft power is highest then, and a motor sized for the hot duty can overload before the process warms up. The cold-start power is the product of the same density ratio: at 600 °C the hot duty is about 34% of the power the same blower absorbs on cold air at the same speed and volume. Starting method, damper position during start-up and the motor’s margin all need to be planned together. The electrical side is covered in motors, drives and starting.

What changes in the machine

• Materials. Steel loses strength as it heats, so the wheel and shaft are engineered for the temperature and the speed.
• Bearings. They must not sit in the heat, so bearing cooling, a longer shaft, and sometimes a heat shield keep them in range.
• Speed limit. Allowable tip speed falls with temperature, so speed and wheel diameter are chosen together.
• Clearances. Differential expansion between wheel, shaft and casing is allowed for, as the last column of the table suggests.
• Balancing. We balance impellers on our own computerised dynamic balancing machines, because unbalance gets worse with speed and size.

Ask for the operating procedure as well as the machine. Hot blowers should be started and stopped in a defined sequence: the process warms up with the damper set, the blower runs through a cool-down after shutdown so the shaft does not bow, and any standby unit is turned over periodically. A supplier who gives you the sequence in writing has thought about how the blower will live, not just how it will perform on test.

Where these blowers work

Furnaces, kilns and ovens, and the process lines around them: recirculation, combustion air preheating, and exhaust. Our application guidance covers steel plants, glass, ceramics and refractories and foundries, where high-temperature duty is common. For combustion air sizing, see combustion air blower sizing.

What we do not build

Pressures above 500 mm WC, radial-blade material-handling duty, very large process fans above 800 HP, and ATEX or spark-resistant blowers are outside our range, and the standard maximum is 500 mm WC (about 4.9 kPa) and 800 HP. If your hot gas carries dust, say so, because the wheel type and wear protection depend on it, and a heavy abrasive duty may fall outside what we build.

Compare suppliers with how to choose a centrifugal blower manufacturer and comparing blower quotations.

What to send us for a quotation

• Gas temperature, normal and maximum, and the gas composition
• Airflow at the gas condition, or in normal cubic metres with the temperature
• Static or total pressure in mm WC or Pa
• Dust loading and the process: furnace, kiln, oven or other
• Start-up procedure and how often the process cycles
• Voltage, frequency, drive preference and available space

Send these to us through our contact page and we will confirm whether the duty is inside our range and select the blower. See the centrifugal blower range and our guide to centrifugal blowers. Our notes for India and Saudi Arabia cover local conditions. Hot exhaust may also need an oxidizer downstream.

Types and variants we build

• High-Pressure Centrifugal Blower Supplier: Up to 500 mm WC, and What That Takes at the Wheel
  High-pressure centrifugal blowers up to 500 mm WC (about 4.9 kPa): the tip speed that pressure needs, a calculated table, and where our range ends.
• High-Temperature Centrifugal Blower Manufacturer: Furnace, Kiln and Oven Duties Up to 800 °C
  High-temperature centrifugal blowers for furnaces to 800 °C, kilns to 650 °C and ovens to 500 °C: how hot gas changes flow, density and the wheel itself.
• Induced Draft (ID) Fan Manufacturer: Sizing for Hot Flue Gas, Draft and Dust
  Induced draft fans pull hot flue gas through a boiler or process: how gas temperature sets volume and power, what a stack adds, and what ID duty asks.
• Stainless Steel Centrifugal Blower Manufacturer: When Stainless Pays and When It Does Not
  Stainless steel centrifugal blowers for corrosive, humid, coastal and washdown duty: a cost-per-year comparison with mild steel and what else to specify.

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