Abstract: A propeller fan assembly that generates lower sound pressure during operation and minimizes blade deflection without sacrificing performance. The blades of the propeller fan comprise silencer seeds located on the suction side of the blades, closer to the leading edge and the tip of the blades. The silencer seeds are sized in increasing face area and form an array with areas increasing with each row. The propeller fan assembly also comprises a dual hub comprising more than one circumferential layer concentric with the axial fan's hub. Multiple circumferential layers provide significant additional support to the blades during operation. This minimizes blade deflection and preserves the performance of the blade as intended. The overall fan and orifice assembly uses a unique assembly method that allows for wide flexibility and permits use of motors of different types and sizes seamlessly with this propeller fan assembly.

Abstract: Plenum fan banding that effectively changes the width of the fan blades in a plenum fan for a HVAC unit. A removable and replaceable band attaches to the back of a fan wheel of the plenum fan so that the band is located within the circle of the fan blades and extends outward perpendicular to the back of the wheel. The band is provided with tabs that insert through slots provided in the back of the fan wheel, and the tabs can be bent over as a means of removably securing the band to the fan wheel. The band effective reduces the functional width of the fan blades in proportion to the width of the band.