The New Dryer Capable of Drying Heat-Sensitive Materials with High Efficiency

Abstract

The dryers are classified into two types, direct heating type and indirect heating type. Generally direct heating type has higher heat transfer rate leading to higher drying capacity but requires more operational costs than the indirect heating type. Our new vacuum dryer “Active Freeze Dryer”, a kind of indirect heating type dryer with a swing arm in the inverse cone-shaped vessel circling slowly along the inner wall and is useful for drying heat-sensitive materials by use of the drying mechanism of sublimation by lowering the air pressure under the triple point to freeze and dry the materials. The ice crystals are formed as the granules with high fluidity and uniformity. This vacuum freeze dryer shows high drying efficiency by the activation of the material inside the vessel and splendid cost performance.