According to the working principle, single-stage and multi-stage centrifugal fans belong to a type of speed fan. Firstly, during the rotation of the working wheel, the gas velocity is increased due to the centrifugal force and the expansion flow in the working wheel. Then, the velocity energy is converted into pressure energy in the diffuser. So what is the difference between single-stage and multi-stage centrifugal fans?
1. Number of impellers
The main difference between single-stage and multi-stage centrifugal fans is that single-stage centrifugal fans only have one set of impellers, and the compression of air is completed in one compression. The multi-stage centrifugal fan has multiple sets of impellers on a main shaft, and the compression of air is gradually completed between the multiple sets of impellers.
2. Rotational speed
Due to the fact that centrifugal fans rely on increasing the flow velocity of air, that is, the kinetic energy of air, to compress air and increase pressure, in order to obtain the same pressure, the impeller of a single-stage centrifugal fan must have a speed several times higher than that of a multi-stage fan. Generally, the speed of a multi-stage fan is only a few thousand revolutions per minute, while the speed of a single-stage fan can reach tens of thousands or even hundreds of thousands of revolutions per minute.
3. Place of use
Due to the fact that the provision of pressure largely relies on the increase of rotational speed, which is limited by factors such as balance, lubrication, and material properties, single-stage centrifugal fans are more commonly used in low-pressure environments, while multi-stage centrifugal fans are more commonly used in high-pressure conditions.
4. Service life
Single stage centrifugal fans generally rely on gearboxes to achieve extremely high speeds. Due to the extremely high speeds, the control and maintenance of the fan are particularly important and must be accompanied by a separate lubricating oil station. At the same time, high speeds cause significant wear on many components such as blades, resulting in a longer lifespan for single pole fans and a lower lifespan for extreme centrifugal fans.
