Advantages and disadvantages of axial flow fan: the advantage of axial flow fan is small volume, almost the size of the air duct. When the blade Angle of axial flow fan can be adjusted, the fan efficiency changes little with the increase and decrease of load. The disadvantage of axial flow fan is that the wind pressure is lower, the blade Angle adjustable axial flow wind mechanism is more complex, the maintenance workload is larger, the highest efficiency of axial flow fan is slightly lower than that of centrifugal fan.