US Patent 7438525 Fan housing

A fan housing and a fan have stationary blades for guiding airflow. Each stationary blade has at least one airflow-guiding element extending therefrom along the circumference of the fan. The side wall of the airflow-guiding element changes the direction of the airflow so that the airflow at the outlet is fully introduced toward the heat source. Furthermore, the airflow-guiding element regulates the airflow, restrains the turbulent flow at the outlet and on the curved surface of the stationary blade, decreases the noise arising from the turbulent flow, and prevents foreign matter from entering the fan housing so as to protect the inside elements thereof.