According to the working principle, single-stage and multi-stage are one type of speed fan, that is, firstly, during the rotation of the working wheel, the speed of the gas is improved due to the action of the rotating centrifugal force and the diffusing flow in the working wheel. The velocity energy is then converted to pressure energy in a diffuser. The difference between the two is that the single-stage centrifugal fan has only one set of impellers, the compression of the air is completed by one compression, and the multi-stage centrifugal fan has multiple sets of impellers on one main shaft, and the compression of the air is gradually completed among the multiple sets of impellers. . Since the centrifugal fan relies on increasing the flow speed of the air, that is, the kinetic energy of the air to compress the air to increase the pressure, so to obtain the same pressure, the impeller of the single-stage centrifugal fan must be several times higher than the speed of the multi-stage fan, usually multi-stage. The speed of the fan is only a few thousand revolutions, while the speed of a single-stage fan is as high as tens of thousands of revolutions or even hundreds of thousands of revolutions. Since the supply of pressure largely depends on the increase of the rotational speed, and the supply of the rotational speed is limited by various aspects such as balance, lubrication and material properties, the single-stage centrifugal fan is more used in low-pressure applications, and the high-pressure working conditions are more. Use a multi-stage centrifugal fan. Single-stage centrifugal fans generally rely on gearboxes to achieve extremely high rotational speeds. Because of the particularly high rotational speed, the control and maintenance of the fans is particularly important. A separate lubrication station must be provided at the same time, and many components such as blades are worn due to high rotational speed. Larger, so the life of a single-pole fan is much lower than that of a centrifugal fan.
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 station and gear transmission;
2. High speed and high noise;
3, the maintenance is large, the maintenance is difficult; because the components of the fan wear fast, and the requirements for balance and assembly are extremely high;
4. The control is complicated and the operation is difficult;
5, the fan is easy to generate vibration;
