Fans and blowers
Which fan, which duty: clean-air, material-handling and high-pressure fans compared
Typical flow and pressure ranges for the main industrial fan families and what each means for the bearing arrangement.
The main families
Industrial centrifugal fans are chosen by the job: clean air or material, direct or belt drive, and the pressure needed. The ranges below are typical for standard commercial fans of the sizes where pillow-block or motor bearings are used.
Typical ranges
| Family | Drive | Flow (m³/h) | Pressure (mm water gauge) | Bearings |
|---|---|---|---|---|
| Clean-air fan | Direct | 2,000 to 88,000 | 120 to 600 | Motor bearings |
| Clean-air fan | Belt | 2,500 to 115,000 | 80 to 600 | Two bearings in a unit |
| Material-handling fan | Direct | 750 to 11,000 | 110 to 440 | Motor bearings |
| Material-handling fan | Belt | 2,800 to 40,000 | 60 to 600 | Two bearings in a unit |
| High-pressure material fan | Belt | 2,000 to 13,000 | 250 to 1,000 | Two bearings in a unit, higher load |
Pressure conversion
One millimetre of water gauge is 9.81 pascals, so 1,000 mm water gauge is about 9.8 kilopascals. Pressures above this are unusual in a single-stage fan of this size. If a calculation shows tens of kilopascals, check the units before relying on the thrust figure.
Reading the table for bearings
- Direct-drive fans use the motor bearings, so the motor must suit the impeller load.
- Belt-driven fans add belt pull on top of the impeller load, and both bearings need the full shaft calculation.
- High-pressure fans carry more thrust: pressure times inlet area, which is the main axial load.
Standard limits
- Standard fans of this kind are rated to about 60 °C without modification. Above that, plan cooling, a high-temperature grease and a bearing clearance check.
- Air density changes with temperature, so power and pressure change with it. Speed may need adjusting.
Takeaway. Match the fan family to the duty first, then size the bearings from the full shaft geometry and the pressure it runs at.
Put it to work in the tool