I. Mechanical wear

 

1. Impeller wear

 

○ Solid particle impact: When a centrifugal fan is used to transport gas containing solid particles (such as sand, dust, mineral powder, etc.), these solid particles will hit the impeller surface at high speed with the airflow. Long-term impact will cause the surface material of the impeller blades to gradually peel off, especially at the leading and trailing edges of the blades, because these parts are where the airflow and solid particles first contact and separate.

 

○ Impeller and casing friction: If the gap between the impeller and the casing of the centrifugal fan is not adjusted properly during installation, or during operation due to equipment vibration, loose foundation, etc., the impeller may rub against the casing. This friction will directly wear the edge of the impeller, reduce the strength and precision of the impeller, and even cause the impeller to deform in severe cases.

 

2. Bearing wear

 

○ Poor lubrication: Good lubrication is required for the normal operation of the bearing. If the lubricating grease is insufficient, deteriorated, or the lubrication system fails, the friction between the balls or raceways inside the bearing will increase. This will cause excessive wear of the bearing components, generate a lot of heat, and then increase the temperature of the bearing surface, further aggravate the wear, and eventually may cause the bearing to get stuck.

 

○ Overload operation: When the working load of the centrifugal fan exceeds the design requirements, such as too high speed, too high wind pressure or too high gas density, the axial and radial forces on the bearing will increase. If the bearing is in this overload state for a long time, the service life of the bearing will be greatly shortened, and it is easy to have wear, fatigue peeling and other faults.

 

3. Shaft wear

 

○ Corrosion: If the working environment humidity of the centrifugal fan is high, or the gas conveyed contains corrosive components (such as acidic gas, salt, etc.), the surface of the shaft may corrode. The corroded shaft surface becomes rough, and the wear is aggravated when it moves relative to other parts (such as seals).

 

○ Wear caused by misalignment: If the motor and fan shaft of the fan are not accurately aligned, additional radial force will be generated during operation. This force will cause the shaft to bend and deform, resulting in uneven wear of the connecting parts such as the shaft and bearing, and the shaft and coupling. In particular, the wear rate will be faster in the stress concentration area on the surface of the shaft.