Method and apparatus for modifying a veil of materials in a drum of a drying apparatus

Apparatus for modifying a veil of falling materials, the veil of materials being generated in a drying and heating region of a substantially horizontally disposed elongate drum of a drying and mixing apparatus, within which drum the drying and heating is effected by a stream of hot gases flowing longitudinally of the drum and traversing the length of the veil of falling materials, the apparatus for modifying the veil comprising:

• at least one baffle plate supported within the drying and heating region of said drum and extending at least partially through the veil of falling materials;
• and
• means for supporting the at least one baffle plate for pivotal movement about an axis disposed substantially parallel to the longitudinal axis of the drum, to change the projected area of the baffle plate with respect to the direction of the falling materials in the veil, whereby a pivotal movement of the at least one baffle plate creates a void of material in the veil below said baffle plate.

Apparatus for modifying a veil of falling materials, the veil of materials being generated in a drying and heating region of a substantially horizontally disposed elongate drum of a drying and mixing apparatus, said drying and mixing apparatus comprising means for generating a stream of hot gases to move longitudinally through said drum and through said veil of falling materials for drying and heating said materials and exit from said drum after having transferred heat energy to said materials, the veil modifying apparatus comprising:

• means, extending at least partially through the veil of falling materials, for deflecting materials from their path in the veil upon impingement of such materials with a projected area of said deflecting means, and for generating a channel void of said falling materials behind said projected area of the deflecting means to enable the hot gases traversing the veil of falling materials to flow through said channel without contacting such falling materials;
• and
• means for altering the size of said projected area of said deflecting means to change a cross-sectional area of said channel, thereby correspondingly altering the quantity of hot gases which flow through said channel, whereby heat conduction from said hot gases to said materials becomes altered as a result of the altered flow of such gases through said channel.

In a drum drying and mixing apparatus for asphaltic materials, including a substantially horizontally disposed cylindrical drum having first and second ends, being supported for rotation about a substantially horizontal, longitudinal axis, and having a drying region with means for generating a veil of falling material in response to material passing through such drying region, means for feeding a first aggregate material into said first end of said drum to pass through said drying region in a direction downstream toward said second end, means for generating a flow of hot gases within and through the drying region of said drum longitudinally of the drum to traverse said veil of falling material and to exit thereafter from said drum, means for introducing a second aggregate material into the drum downstream of said drying region, wherein the improvement comprises:

• means disposed within the drying region for deflecting material in said veil of falling material and for generating a passage through at least a portion of veil of falling material;
• and
• means for gradually altering the effectiveness of said deflecting means to increase the effectiveness of said deflecting means in response to an increase of material flow through said drying region and to decrease the effectiveness of said deflecting means in response to a decrease of material flow through said drying region.