Reasons for vibration in the exhaust flue of the centrifugal fan
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The desulfurization booster fan for the 75t circulating fluidized bed is a centrifugal fan. During normal operation, the adjustment damper of the centrifugal fan is set at 28%; why is the vibration in the exhaust duct at the fan’s outlet high and are the pulsations noticeable? Could experts please provide an answer? Anxious anticipation. . . . !
Possible reasons: 1. The steel plate of the smoke duct is too thin, with no support provided; 2. The cross-sectional area of the duct design is too small, resulting in too high a flow velocity of the smoke gas.
It’s best to handle this as soon as possible: 1. Install shock absorbers at the fan outlet; 2. Increase the cross-sectional area of the air ducts to reduce the airflow velocity inside them; 3. Adjust the baffles, which can be installed at the fan inlet
This post was last edited by blueseabreeze on 2011-8-12 09:23. Reply to 3# gao0xxx1985: 1. The adjustment baffle is installed at the fan inlet, and the vibration levels in all directions of the fan shaft are within acceptable limits； 2. An expansion joint is directly connected after the fan outlet ； 3. There is no vibration in the flue starting from behind the fan’s expansion joint; the maximum vibration occurs at a distance of about 8 meters behind the fan ； 4. There is no issue with the strength of the flue; it is already designed to be extremely strong ； 5. The flue gas velocity is also within 12 meters. Ken asks everyone to continue analyzing it
Reply to 4# blueseabreeze: It’s probably due to fittings such as elbows; it’s definitely an issue with air flow, as it can’t be caused by fan vibration. The vibration is surely related to the air flow inside the pipes, so check the pipes
Good topic; great job. Our factory has encountered this problem as well.
It is possible that dust has accumulated on the impeller of the fan, causing increased vibration; it is recommended to shut down the machine for cleaning!
It might be due to an offset in the center of gravity; our factory has encountered such a situation before
When the center of gravity of the fan is offset, and this center deviates from the center of the blade root section, the centrifugal force resulting from high rotational speeds, along with changes in the lift on the blades caused by unstable airflow, can easily induce blade vibration. The traditional repair method involves removing the impeller, placing it on a static balance machine to determine the degree of imbalance, welding counterweights, and then reinstalling the fan after verification that the imbalance has been corrected.
It is obvious that the pipeline itself is the cause; it is recommended to 1. add another expansion joint； 2. Reinforce the vibrating area.