Fan Wheels Types, Features, Applications

Buffalo HT Fan Company designs, manufactures, and repairs almost all types of industrial fans, with an emphasis on exotic alloy and high temperature fans to 2,000 F and beyond, in both centrifugal and axial flow designs.

Fan problems and failures are often due to fans having been misapplied. Examples include: Backward inclined, backward curved, or airfoil fans used in dirty airstreams. High speed fans used in wet scrubber applications. Or improperly sized fans operating with poor efficiency, or reduced airflow.

Questions we are often asked include: What fan type is best for my application? What types of fans are available? How do I compare the various fan types from one manufacturer to another? Where do I start?

For a quick explanation of the basic fan types, click here to review our 1 page fan type datasheet that explains the different blade types, and their common applications. The names will likely change with every manufacturer, but the blade types are basically unchanged.

Next, to get an idea of which fan types may be suited to your application, solve the simple specific speed (Ns) formula below to see which types of fan are possible to use in your application at a particular RPM. Then, consider which of the available fan types will work for your application.

See the example below.
(For a single inlet fan: Ns = RPM  x   /(Ps).75)

Example: what is the Ns for a single inlet (SWSI) fan to handle 5,000 SCFM, 16” static pressure, running at 1750 RPM? (NOTE: always convert to standard density conditions before calculation.) Answer: 15,468        

Next, what fan types could be used? A radial blade, radial tipped blade, and backward curved fan are likely choices. Next, consider the application? If it’s a dirty airstream, the radial is best, the radial tipped is good, and the backward curved is a poor choice. If the airstream is clean, use any of them. If efficiency is most important, use the backward curved, or the next highest efficiency radial tipped if the airstream is dirty. More efficient fans tend to be larger, and more expensive, with the airfoil being the most expensive design.

Specific speed (Ns) is useful to determine what fan types are suited to an application. In general terms, a high specific speed number will be a higher volume and lower pressure fan. A low specific speed number will be a lower volume and higher pressure fan.

To learn more, or for assistance selecting your next fan, please contact us at:  engineering@buffalohtfan.com