What makes a fan backward curved
A backward curved fan is a centrifugal fan with a backward curved (also called backward inclined) wheel. The wheel has fewer, larger blades than a forward curve wheel, and they lean back, away from the direction the wheel turns. Some are flat, some are curved and some have an airfoil shape.
Backward curved vs forward curve
| Backward curved | Forward curve | |
|---|---|---|
| Speed | High | Low |
| Pressure | Medium to high | Low to medium |
| Efficiency | Higher | Lower |
| Power draw | Levels off, hard to overload the motor | Rises with airflow |
| Size for the same air | Larger | Compact |
More detail is in forward curve vs backward curved blower wheels.
Where backward curved fans are used
- General supply and exhaust in commercial and industrial buildings
- Kitchen and restaurant exhaust, in belt drive utility sets
- Larger air handlers and industrial ventilation
What we build
Our backward curve utility sets run from 10" to 49" and move up to 63,000 CFM. We also build backward curved wheels to order in steel, stainless steel and aluminum, matched to a worn original or a drawing. Send photos and measurements, or ship us the old wheel, and we quote price and lead time.
Questions
Is backward curved the same as backward inclined?
In everyday use, yes. Both describe blades that lean away from the direction of rotation. Strictly, backward inclined blades are flat and backward curved blades are curved, but they work the same way.
Can I replace a forward curve blower with a backward curved fan?
Sometimes, but not by swapping the wheel. The housing, speed and motor are different, so it means a new fan. Call us and we look at what you have.