There are many faults that occur during the operation of centrifugal fans, but they can basically be classified into two categories, namely fan performance faults and mechanical faults. This article mainly introduces the causes and treatment methods of fan faults. Let’s take a look!
01 Vibration caused by rotor imbalance
1. Cause of failure: The blades of the fan are corroded or worn seriously.
Treatment method: repair or replace the fan blades.
2. Cause of failure: The fan blades do not run after assembly, and the shaft is bent due to the weight of the impeller and the main shaft.
Treatment method: re-check and overhaul. If it is not used for a long time after assembly, it should be cranked regularly to prevent the shaft from bending.
3. Cause of failure: uneven attachment on the surface of the impeller, such as rust, dust accumulation, etc.
Treatment method: remove attachments.
4. Cause of failure: Transportation, installation or other reasons cause the deformation of the impeller and cause the impeller to be unbalanced.
Treatment method: repair the impeller, and re-do the dynamic and static balance experiment.
5. Cause of failure: the balance block on the impeller fell off or the balance was not found after maintenance,
Treatment method: add balance blocks, do dynamic balance, and then find balance.
02 Resonance caused by the fan’s fixture
1. Cause of failure: the cement foundation is too light or the grouting is poor or the plane size is too small, causing the fan foundation to be disconnected from the foundation, the anchor bolts are loose, and the machine base is not firmly connected, so that the foundation rigidity is not enough.
Treatment method: reinforce the foundation or re-grout, and tighten the nuts.
2. Cause of failure: the rigidity of the fan base or the volute is too low.
Treatment method: strengthen its rigidity.
3. Cause of failure: The inlet and outlet pipes connected to the fan are not supported or softly connected.
Treatment method: add support and soft connection.
4. Cause of failure: the adjacent facilities are too close to the foundation of the fan, or its stiffness is too small.
Treatment method: adjust the spacing with adjacent facilities and increase foundation stiffness.
03 Bearings overheated
1. Cause of failure: the main shaft or the parts on the main shaft rub against the bearing housing.
Treatment method: Check the friction position and deal with it.
2. Cause of failure: the motor shaft and the fan shaft are not concentric, which makes the inner rolling bearing in the bearing box not strong.
Treatment method: adjust the concentricity of the two axes (alignment).
3. Cause of failure: Too much grease in the bearing housing.
Treatment method: The grease in the box is 1/3~1/2 of the box space.
4. Cause of failure: There is a gap between the bearing and the bearing box hole and it is loose, and the bolts of the bearing box are too tight or too loose.
Treatment method: Adjust the bolts.
04 Bearing wear
1. Cause of failure: Pockmarks, grinding spots, rust marks and other phenomena appear on the surface of rolling bearing balls.
Treatment method: Repair or replace.
2. Cause of failure: The gap between the inner circle of the cylindrical bearing and the outer circle of the rolling bearing exceeds 0.1mm.
Treatment method: The bearing box should be replaced or the inner circle of the box should be enlarged and then inserted into the inner sleeve.
