Quadpass Dryer
The new dual-zone, four-pass rotary drum dryer from Dupps--the only proprietary rotary drum dryer design on today's market--cuts energy costs by producing high thermal efficiencies. It improves product quality by preventing thermal degradation. Equally important in many applications, it also reduces pollution and provides greater fire safety than conventional drum dryer designs.
The four-pass design disrupts laminar (layered) gas flows to create multiple eddy flows that turbulate and separate. Time, temperature and turbulence controls allow maximum dryer performance.
Ordinary three-pass drum dryers are subject to over drying, material volatilization, pyrolysis (chemical decomposition by heat), smoke, excess fines, clogging, and even fires. The primary cause of these problems is the flow design. Material starts drying at high air velocity then drops at each stage, eventually slowing to fallout velocities, resulting in accumulation. This accumulation requires re-entrainment and acceleration to pneumatic conveying velocity in order to exit the drum.
The new four-pass drum dryer solves these problems by starting at the slowest velocity, then getting progressively faster. This dries each particle of material at its individual drying rate, regardless of that particle's size, density or moisture. When dried, each particle exits the drum without overheating or volatilizing.
The Dupps Company, P.O. Box 189, Germantown, OH 45327. Tel: 513-855-6555; Fax: 513-855-6554.