The difference between multi-stage and single-stage high-speed centrifugal fans

According to the working principle, both single-stage and multi-stage belong to a type of speed fan. Firstly, during the rotation of the working wheel, the centrifugal force and the expansion flow in the working wheel increase the velocity of the gas. Then, the velocity energy is converted into pressure energy in the diffuser. The difference between the two is single levelcentrifugal fanThere is only one set of impellers, and the compression of air is completed in one compression, while multi-stage centrifugal fans have multiple sets of impellers on one main shaft, and the compression of air is gradually completed between multiple sets of impellers. 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. 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. 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.

The main disadvantages (relative) of single-stage centrifugal fans are:

1. The mechanism is complex, and the unit has auxiliary mechanisms and settings such as lubricating oil stations and gearboxes;

2. High speed, loud noise;

3. Large maintenance volume and high maintenance difficulty; Due to the rapid wear and tear of fan components, as well as the extremely high requirements for balance and assembly;

4. Complex control and high operational difficulty;

5. Fans are prone to vibration;