What are the main differences between centrifugal fans and Roots blowers? How to make the right choice in the application?

Centrifugal fans and Roots fans are widely used in pneumatic conveying fan types. Although many people know that they need to be distinguished in application occasions, the principle, manufacturing and parameter differences between the two fans are half-known and half-solved.

The difference between centrifugal fan and Roots blower, mainly has the following points:

Difference 1: working principle

Centrifugal fans use curved blades, and then send the gas to the casing by centrifugal force, while Roots fans use 8-shaped blades to squeeze the gas to the air outlet.

Difference 2: Site Requirements

Centrifugal fans are mainly used in places with low pressure and relatively large air volume, while Roots fans are used in places with high pressure and relatively small air volume.

Difference three: manufacturing precision

The manufacturing precision of centrifugal fan is not high, and the manufacturing precision of Roots fan is relatively high.

Difference four: parameters

The load requirement of centrifugal fan is constant pressure, so it is a kind of constant pressure fan, the change of wind pressure is not big, and has the square torque characteristic.

Roots blower is a constant flow fan, its main parameter is air volume, and the air volume changes very little. And Roots blower is a high-pressure fan, conveying air volume and revolution is proportional.

If the load requires a constant flow effect, use a Roots blower. Because Roots blower is a constant flow fan, the main parameter of work is air volume, the output pressure changes with the change of pipeline and load, and the air volume changes very little. Roots blower is a high-pressure fan, Roots blower is a positive displacement fan, the amount of air delivered is proportional to the number of revolutions, the gas from the side of the suction to the side of the discharge. If the load requires a constant pressure effect, use a centrifugal fan. Because the centrifugal fan is a constant pressure fan, the main parameter of the work is the wind pressure, the output air volume changes with the change of the pipeline and the load, and the wind pressure changes little. Centrifugal fan, wind pressure is not big. The compression process of air is usually carried out under the action of centrifugal force through several working impellers (or several stages). Centrifugal fan belongs to the square torque characteristics, while the roots fan basically belongs to the constant torque characteristics.