There are many ways to adjust the air volume of the centrifugal fan, such as inlet and outlet air valve regulation, spiral line air valve regulation, inlet blade regulation, revolution regulation and so on. For different types of fans, the energy-saving effect is very different due to different adjustment methods.
1. Air valve regulation: The centrifugal fan outlet air valve adjustment is to change the characteristics of the pipe network, rather than change the characteristics of the fan. The air volume adjustment range is usually suitable for all operating conditions below the fan rated performance curve. Due to the use of artificial increase of pipe network resistance to change the characteristics of the pipe network, pressure drop consumption in the small wind valve when the additional resistance. The adjustment economy is poor.
2. Inlet air valve regulation: When the pipe is arranged on the suction side of the fan, the regulation principle is the same as that of the outlet air valve. But when the pipe is arranged on the exhaust side of the fan, it changes the performance curve of the fan by changing the inlet pressure of the fan, so the adjusting economy is good.
3. Spiral line air valve regulation: The characteristics of the fan are changed by changing the outlet area of the fan. Compared with the reduction of air volume, the power change is small and the energy saving is not significant. These two adjustments, in principle, can be used under the rated curve of all operating conditions, can make the surge point to the direction of small flow. Therefore, they are widely used in general with a fixed speed fan.
4.The inlet blade regulation is to change the direction of the air flow of the suction impeller and change the performance curve of the fan by adjusting the blade. The positive rotation regulation of the air flow at the inlet of the fan can realize all working conditions below the performance curve when the angle of the inlet guide vane is zero degrees. The negative swirl regulation of the inlet air flow can improve the pressure and flow rate of the fan, but the regulation range has a certain limit. Because of the wide adjustment range and high economic efficiency of imported blade adjustment, and it can realize automatic adjustment, it is widely used by fans.