The drum scraper dryer is an internally heated conductive rotary continuous drying equipment. As the rotating drum passes through the material trough at its lower part, a material film of certain thickness adheres to the drum surface. Heat is delivered through pipelines to the inner wall of the drum, conducted to the outer drum wall and then transferred to the material film. The moisture within the film evaporates and is removed to dry the wet material. The dried material is scraped off the drum by the scraper fitted on the drum surface and falls onto the screw conveyor beneath the scraper. The screw conveyor then collects the dry material for packaging.
Working Principle
Liquid or slurry materials form a thin film on the drum surface heated by steam or other heat carriers. The material is fully dried within one full rotation of the drum. The finished product is scraped off by a scraper. The exposed drum surface comes into contact with raw materials again to form a new material film for subsequent drying.
Technical Parameters
Product Features
● High drying rate: Owing to the thin material film and consistent directions of heat and mass transfer, the vaporization intensity on the film surface can reach 30–70 kg H₂O/(m²·h).
● Wide operating flexibility: Broad adaptability to various materials and different output requirements.
● High thermal efficiency: The typical thermal efficiency ranges from 80% to 90%.
● Short drying time: The material drying cycle is generally only 10–300 seconds, making it suitable for heat‑sensitive materials. When installed inside a vacuum chamber, the drum dryer can operate under reduced pressure.
Product Applications
The drum scraper dryer is suitable for drying liquid and relatively viscous materials in chemical, dyestuff, pharmaceutical, food, metallurgical, yeast and other industries. It can produce flaky, powdery and granular dried food products such as rice flour, oatmeal, alpha starch and whole potato powder.