Patent attributes
An improved geometry for flights used in rotary drums of aggregate dryers in the manufacture of asphalt causes the aggregate to shower in an even veil across the full width of the drum under all loading conditions. An opening in the flight having a narrow bottom and wider top allows more aggregate to shower early, especially when flights are lightly loaded, on the uplift side of the drum to complete the aggregate veil and prevent hot gases from bypassing. The opening is oriented with its narrow bottom nearest the inner surface of the drum and its wider top farthest therefrom. The opening does not extend through the full height of the flight, which would form an undesired gap allowing an excessive volume of aggregate to flood out of fully loaded flights on the uplift side of rotation. Such flooding discharge causes a similar imbalance of drying to that caused by too little discharge from light loaded flights. The size and shape of the opening can be varied to adjust the amount of aggregate discharged from each flight to form the veil and to adjust the shape of the veil.
