Measures to prevent fan from surging are as follows:

1, so that the pump or fan flow constant is greater than QK. If the required flow in the system is less than QK, the recirculation pipe or the automatic discharge valve can be installed, so that the exhaust flow of the fan is always larger than that of the QK. surge alarm device

2, if the pipeline performance curve does not pass the coordinate origin, change the fan speed, may also obtain the stable operating condition. The fan speed of various parabolic maximum pressure performance curve the performance curve of fan split into two parts, the right for the stable working area, left for the unstable working area, when the pipeline performance curve through the origin of coordinates, change the speed of no effect, so the speed of the working point is similar operating point.

3 、 the axial flow fan adopts adjustable blade adjustment. When the required flow rate of the system is reduced, the installation angle is reduced, the performance curve is moved down, the critical point moves to the left and the output flow is correspondingly reduced.

4, the most fundamental measure is to avoid using the hump shape performance curve fan, but uses the performance curve straight downward downward fan.