US Patent 11635087 Airflow-doubling vane structure

An airflow-doubling vane structure includes an axle, an inner vane unit, and an outer vane unit. The inner vane unit includes a plurality of vanes provided around a center defined by the axle and can be rotated along with the axle. The vanes of the inner vane unit are centrifugal vanes. The outer vane unit includes a plurality of vanes provided around the center defined by the axle and around the inner vane unit and can be rotated along with the axle. The vanes of the outer vane unit are axial-flow vanes and extend a certain radial distance from the vanes of the inner vane unit.