Sollant:Do you know the reason for the large vibration of the centrifugal fan?

Centrifugal fan introduction related knowledge

Centrifugal fans are a common and important type of fan. It is widely used in refrigeration, ventilation and air conditioning systems and other fields. Its working principle is based on the principle of centrifugal force and kinetic energy conversion. Air is sucked in by the rotating impeller and expelled centrifugally.

Centrifugal fans are composed of main parts such as impellers, driving devices and casings.

Among them, the impeller is also called the volute. It is surrounded by a series of curved blades. The air is accelerated by rotation and a powerful airflow is generated. The drive is responsible for rotating the impeller. Common drive arrangements include electric motors, belt drive systems, or direct drive systems. The shell is used to seal and guide the air flow, ensuring that the air flows in the correct direction.

Compared with other types of fans, centrifugal fans have some advantages and characteristics of their own.

The first is their high air volume and high pressure capabilities. It can provide stronger airflow and is suitable for occasions that require a large amount of airflow and higher airflow pressure. Additionally, centrifugal fans are capable of ducting airflow over long distances. Overcome pipe resistance and air resistance, so that air can be efficiently piped to where it is needed.

Centrifugal fans also perform well in cooling applications.

Thanks to their high air volume and pressure, they are able to expel hot air quickly and carry it away, providing better cooling. This makes centrifugal fans ideal for cooling computers, cooling electronics, and industrial and commercial transformation systems.

Another notable feature is the relatively low noise level of centrifugal fans.

Due to the reduced impeller speed, the noise generated when the air passes is reduced. This makes centrifugal fans more popular in noise-sensitive applications.

In addition, centrifugal fans also have advantages in terms of space utilization.

They are relatively compact in design. Induce efficient spatial amplification. Suitable for applications where space is limited. Whether it’s a compact electronic device or a ventilation system, centrifugal fans are able to provide high volumes of air movement while saving valuable space.

The reason for the large vibration of the centrifugal fan

1. Uneven wear and surfacing electrodes

First of all, during the operation of the centrifugal fan, the impeller is worn by the flue gas. Wear-resistant performance can be increased by surfacing wear-resistant electrodes and coating wear-resistant coatings on the surface of airfoil blades. However, due to the unevenness of the wear of each blade, the unevenness of the amount of surfacing welding electrodes, and the unevenness of the application of anti-wear coatings, it will cause the dynamic imbalance of the centrifugal fan after it is started.

2. Centrifugal fan blades enter ash

Secondly, the general airfoil blades are hollow. The hoof-shaped corners and the web are worn through by the flue gas, causing the blades to enter ash. With the accumulation of ash, the center of gravity of the impeller shifts to cause dynamic imbalance, which increases the vibration.

3. Wheel alignment data is inaccurate

Furthermore, due to the self-weight of the rotor of the centrifugal fan, the rotating shaft produces a downward deflection. When aligning the wheel, it is necessary to consider the amount of radial upward runout and the upper opening of the back wheel on the fan side caused by this factor. That is to say, when aligning, it must be ensured that the opening on the alignment wheel and the side of the motor are low. The alignment standard is 0.2mm lower than the motor side and 0.15mm upper opening. If it is completely aligned according to the rigid rotor, a large vibration will be generated.

4. Thermal bending of the rotor

Finally, in the start-up phase of the centrifugal fan unit. When the fan is operated in a single series, the rotor of the other unused fan will be bent due to the heating of the flue gas. According to the actual measurement, even when the crank is put in, the deformation of the rotor is still relatively large, and the crank cannot eliminate this deformation. In this way, the center of gravity of the rotor is shifted, causing the centrifugal fan to vibrate beyond the standard when it is started again, making it unusable.

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