Method Of Preventing Centrifugal Blower Surge

(1) The performance of the centrifugal blower should be in the high efficiency zone.

Do not artificially increase the selection factor, and the actual flow of the centrifugal blower in actual operation is much higher than the design flow. If a large amount of throttling is used, it is easy to adjust the centrifugal blower to the surge area. For this reason, in the design and selection of the centrifugal blower, it is necessary to avoid the range of working conditions approaching the surge zone.

(2) The centrifugal blower can adjust the operating range by changing the speed of the centrifugal blower once the system is running.

Centrifugal blower can change the diameter of the impeller, and the axial blower can change the installation angle of the blade. These methods can make the performance curve of the centrifugal blower move to the small flow area. At this time, the surge critical line moves to the small flow area accordingly. This can also expand the range of stable operating conditions of the centrifugal blower.

(3)Since some working conditions do not have the above adjustment conditions

And can not stop and affect production, there is a simple and quick adjustment method to eliminate surge, that is, add a bleed valve.The disadvantage of this method is that the momentum obtained by the impeller is partially removed, so that the overall efficiency of the centrifugal blower is reduced. However, because of its simple method and remarkable effect, it is widely used in the mediation of centrifugal blower.

(4) Two-valve operation method.

Two valves are arranged on the centrifugal blower exhaust pipe to fix the volume between the two valves to a certain value. The volume between the two valves is equivalent to a gas storage tank, and the first valve is directly installed at the centrifugal blower outlet. In the closer position, it is equivalent to a throttle valve, which is slightly throttled to prevent surge, while the second valve acts only as a resistance. Practice has proved that this device can not only achieve stable operation of the system, but also is beneficial to reduce noise.

(5) Anti-surge ring.

At present, in the centrifugal blower equipment for subways or tunnels, it has become a common trend to add a Feng anti-vibration ring to the main air duct. This type of baffle can generate an unsteady air flow when the airflow appears to be detached from the airflow. The blade is flowed back in the opposite direction along the deflector. The disadvantage is that part of the airflow is useless in this case, but she can expand the stable operating range of the centrifugal blower and reduce the surge area.