What are the advantages of the backward curved fan impeller?

- May 31, 2019-

The backward curved fan impeller is characterized by its cylindrical shape, several large curved blades and a tapered inlet nozzle. When the fan blade that is bent backwards rotates, a pressure difference is generated on the impeller blades. On the convex side of the impeller blades, a force is generated in the air during the rotational movement of the impeller to generate a positive pressure. The impeller blades push the air outward and exit in a radial manner.


On the concave side of the impeller blades, when the fan blade that is bent backward is rotated, a negative pressure is generated to draw air into the gap between the blades. Then, in a continuous process, this air is driven outward by the blades below. The suction side of the impeller vane draws in the air at the center of the fan, causing a change in the direction of the airflow between the inlet and the 90° exhaust.


The optimum operating area of the fan blade that is bent backwards is the middle part of its performance characteristics, and it exhibits the best working condition when operating at intermediate pressures and intermediate flows. The advantage of using a backward-curved fan impeller is that it has no stall point, the highest static efficiency of any fan type and the mechanism for generating airflow, which means it can also be used in a plenum or in a rolling space to direct airflow. discharge.