Bearing damage, leading to cause vibration.

Counting the best range, so as not to cause more noise. Axial flow fan if a fixed wing and static wing configuration, both the number of blades is best unequal.

Check - before installation must check fan inside presence of entities sundry, if yes, is clear.

Although say now society is the main energy of natural gas and other energy sources, but coal is still has its application area.

Centrifugal blower in use process, if there is a severe vibration, so is very bad, because will affect the normal use of fan.