Spray dryer discharge system

In a spray drying apparatus having a cylindrical drying chamber, said chamber having an upper portion and a second lower, inverted, conically-shaped, solids discharge portion;

• spray means for dispersing a liquid into the form of a mist of fine droplets in said upper portion of said drying chamber;
• conduit means for introducing a stream of hot gas into said chamber and into direct contact with said liquid droplets;
• exhaust conduit means for withdrawing said hot gas from said drying chamber;
• and a discharge outlet positioned at the apex of said inverted conically-shaped solids discharge portion for removal of particulate solids, the improved apparatus comprising the combination of:
• 1. a high velocity rotating disc for dispersing said liquid in the form of fine droplets in the upper portion of said drying chamber;
• 2. conduit means for introducing said stream of hot gas, comprising a gas distribution head provided with a series of intermittently spaced vanes which cause said stream of hot gas to be distributed radially and into direct contact with said mist of fine droplets for vaporizing said droplets, a downward flow of dry solids thereby being established within said chamber;
• 3. exhaust conduit means within the upper portion of said drying chamber for drawing said hot gas from the downward flow of dry solids;
• 4. a series of apertures cut into said conically-shaped discharge portion immediately above said discharge outlet;
• 5. an exhaust fan positioned downstream of said discharge outlet and in direct operable communication therewith, said exhaust fan (a) providing suction at said outlet for drawing cool ambient air into said discharge portion through said apertures, said ambient air being further cooled by expansion thereof as said air is drawn into said chamber through said apertures, and (b) drawing said cooled ambient air along with said dried solids through said discharge outlet;
• and
• 6. a solids separator intermediate of said exhaust fan and said discharge outlet, and in operative communication therewith;
• cohesive solids thereby being air-conveyed from said discharge portion of said chamber and drawn immediately to said solids separator, the cooling effect of said ambient air on said dried solids tending to reduce tackiness in said solids.