"Blower Fan" inlet guide vane adjustment device that is in the vicinity of the blower suction inlet provided a set of adjustable vanes corner - the inlet guide vane, its role is to take place in the gas stream before entering the rotating impeller, causing distortion speed. Vanes can be rotated about its own axis, a rotation angle of each blade means converting a vane mounting angle, so that the direction of air flow into the fan impeller changed accordingly. "Blower Fan" centrifugal fan with inlet guide vane adjustment method, a high efficiency and a wide range of performance at part load operation, while maintaining a constant outlet pressure conditions, the work flow can be 50% to 100% of the rated flow rate in the range of Variety. Adjust the depth of the greater, the more the provincial power. "Blower Fan" such as reducing the flow to 60% of the rated flow rate when the inlet guide vanes way than the meter-way power savings of up to 17 percent.