With the continuous development of industry, sometimes because of the special needs of the working scene, it is necessary to adjust the air volume of the centrifugal fan to make the air volume meet the required conditions.
At present, there are two ways to adjust the air volume of the fan, one is the adjustment of the valve, and the other is the adjustment of the inlet blade. Each adjustment method has different adjustment effects, such as air valve adjustment and outlet air valve adjustment, which change the characteristics of the pipe network.
The air volume regulation range is usually under all conditions of the rated performance curve of the fan. Due to the change of the characteristics of the pipe network by manually increasing the pipe network resistance, the additional resistance generated by the closing of the small air valve consumes the pressure drop, and the regulation economy is poor.
Regulation of air inlet valve: when the pipeline is set at the suction side of the fan, the regulation principle is the same as that of the air outlet valve; When the pipe is set on the discharge side of the fan, the performance curve of the fan is changed by changing the inlet pressure of the fan.
The regulation of spiral air valve changes the characteristics of the fan by changing the outlet area of the fan. Compared with reducing air volume, the power change is small and the energy-saving effect is not significant.
In principle, these two adjustment methods can be used under all conditions under the rated curve to move the surge point to the direction of small flow. Therefore, it is widely used in constant speed centrifugal fan. Inlet blade adjustment is to adjust the blade to change the flow direction of suction impeller and change the performance curve of fan. The positive winding regulation of inlet flow of centrifugal fan can reach all working conditions below the performance curve when the inlet blade angle is zero. The negative winding regulation of intake air flow can increase the pressure and flow of fan, but the regulation range is limited.
Therefore, when the air volume of the centrifugal fan needs to be adjusted, a more appropriate method can be selected according to the structure and use requirements of the fan, so that the fan can reach a good operation state without damaging the fan body. Increase the air volume to meet the requirements of its working conditions.
