Industrial fans are mostly used to transfer fluid, typically gas or air in many applications. Obtaining high performance fans has been a challenge due to vibration-related issues and harsh environments: temperature, fluid, and humidity. Vibration has been known to reduce the lifetime of fans, decrease energy efficiency, and increase downtime and labor costs. It is mostly generated by unbalanced impellers. Impellers have to be balanced according to ISO 1940 after production, and re-balancing may be required during operation due to corrosion, crack, deposits, etc. Vibration-induced unbalanced impellers can be found in a blog here.
Fans can be divided into two types: centrifugal and axial flow fans. Centrifugal fans are also called radial flow fans. The air usually enters the casing from the impeller’s axial direction and is discharged at the periphery of the impeller. Centrifugal fans may be either centre-hung: impeller is located in between two bearings or over-hung: impeller is located outside two bearings. The flow of air in axial flow fans is parallel to the impeller axis.
Regardless the fan types, in general fan fault can be summarized as follows:
