Multistage Centrifugal Blower

Centrifugal blowers are also called turbine blowers. The gas obtains increased pressure and flow rate under the action of the rotating impeller, which can achieve continuous air supply. Its working principle is that when the motor rotates to drive the fan impeller to rotate, the gas is thrown out and changes its flow direction under the action of centrifugal force, and the kinetic energy is converted into static pressure energy. The gas is discharged from the exhaust port, and a certain negative pressure is formed between the impellers, so that the external gas is replenished under the action of atmospheric pressure to achieve the purpose of continuous blowing. Centrifugal blowers are divided into multi-stage centrifugal blowers and single-stage centrifugal blowers according to the number of impellers. Multi-stage low-speed centrifugal blowers normally refer to centrifugal blowers with two or more impellers connected in series on the same main shaft, with up to eight levels of fan blades and a rotor speed of 3000~3600r/min. Centrifugal blowers generally use inlet throttling to adjust the flow and pressure, so that the fan can operate at a lower power, does not require air discharge adjustment, and can maintain high efficiency basically the same as the rated working conditions, and is used for working conditions where pressure and flow are unstable.
The air delivery volume of multi-stage centrifugal blowers is generally large, but the wind pressure generated is not high. The outlet gauge pressure is generally ≤110kPa, and the flow rate is generally around 130m3/min. Compared with Roots blowers, low-speed multi-stage centrifugal blowers have gradually replaced Roots blowers in foreign sewage treatment plants since the 1980s due to their advantages such as low noise, stable and reliable fan operation, and high efficiency. However, they still have disadvantages such as large size, heavy weight, poor flow regulation performance, low efficiency, and high energy consumption.