The short answer
A squirrel cage blower wheel is a forward curve centrifugal fan wheel: a drum of many small, cupped blades held between two end rings, with a hub that mounts it on a motor or shaft. It got its name because it looks like the exercise wheel in a squirrel or hamster cage. In the trade it is also called a blower wheel, fan wheel, centrifugal impeller or forward curve wheel.
How it works
The wheel turns inside a scroll shaped blower housing. Air enters the center of the wheel, the blades throw it outward, and the housing collects it and pushes it out the discharge. That is a centrifugal blower. Because the blades are small and cupped, a squirrel cage wheel moves a lot of air at low speed, so it is quiet and compact.
Where squirrel cage wheels are used
- Furnaces, air handlers and fan coils (HVAC blowers)
- Utility sets and direct drive blowers for kitchen, restroom and building exhaust
- DWDI air kits and plug fans built into OEM equipment
- Ovens, dryers and process equipment
Materials
We build squirrel cage wheels in steel, stainless steel and aluminum. Steel is strong and economical. Stainless steel resists corrosion in kitchens, pools and chemical air. Aluminum is light and does not rust. Every wheel has double riveted blades and is dynamically balanced.
Single or double inlet
A single inlet wheel is open on one side. A double inlet (DWDI) wheel is open on both sides and moves about twice the air. See single vs double inlet.
Replacing a squirrel cage wheel
To replace one, you need the diameter, width, bore and rotation. Here is how to measure it. Then look up your size on the size chart, or send us photos and we build an exact match from 6" to 40".
Questions
Is a blower wheel the same as a fan wheel or impeller?
Yes, they are different names for the rotating part of a centrifugal blower. Squirrel cage usually means the forward curve type.
Can a squirrel cage wheel be repaired?
Often. If it is structurally sound we can clean, rebalance or rebuild it. Cracked or corroded wheels should be replaced.