Basic structure of centrifugal fan
Imported guide vane, collector, impeller, casing, shaft, bearing seat and other components.
Near the inlet in front of the centrifugal fan impeller, there is a guide vane (static guide vane) with adjustable angle, which regulates the fan flow through the opening of the guide vane. By adjusting the opening degree, the operating point of the fan can be changed to meet the different operating requirements of users. Compared with the simple valve throttling regulation mode, this mode can make the air flow pre swirl into the impeller, improve the internal flow of the impeller, and greatly improve the overall efficiency of the fan.
Impeller: the gas pressure is increased by centrifugal force, which is composed of blade, front disc, rear disc and hub
According to the relationship between the outlet direction and the rotation direction of the impeller, the blade type of centrifugal fan can be divided into backward type, forward type and radial type.
Backward blade: the bending direction of the blade is consistent with the natural motion trajectory of the gas, with low energy loss and noise, high efficiency and low noise.
Backward blade: straight plate, curved plate, airfoil (hollow)
Forward blade: the bending direction of the blade is opposite to the movement track of the gas. The gas is forced to change the direction, resulting in large noise and energy loss and low efficiency. The total wind pressure is high.
Radial blade: it is required that it is not easy to accumulate dust, such as powder exhauster.
Composition of air collector:
The current collector is installed in front of the impeller so that the air flow can evenly fill the inlet section of the impeller
Cylindrical: vortex zone will be formed at the inlet of impeller, and the effect is worse when air is directly fed from the atmosphere.
Conical: better than cylindrical, but it’s too short to work well.
Arc: better than the first two.
Cone arc: the best, high-efficiency fans basically use this kind of collector.