Centrifugal fan impellers with blades secured between plates

摘要

A fan impeller comprises a back plate, a front plate and a plurality of blades fixedly attached between the front plate and the back plate. Two bars are welded to the back of each blade and are bolted to the front and back plates. Each blade is a channel section member having a base and two sides, the base being normal to the planes of the front and back plates of the impeller, one side lying along the front plate and the other side lying along the back plate. The sides extend from the base in the direction of rotation of the impeller in use so that the inside of each channel section is presented to the airstream as the impeller rotates. The inside working surface of each blade may be hardened to a minimum hardness of Rockwell C55.