Dedert's Roto-Flash dryer can be described as an agitated flash dryer. The process results in a fine powder directly from the feed material, without the need to premix with already dried product. The air residence time is just a few seconds, making the dryer cost effective both in terms of investment and running costs.
The drying process accepts cakes, pastes, fluids and powders and produces a fine powder with a uniform moisture content and consistent particle size distribution. Additional benefits include:
Compact single pass dryer
No external back-mixing or product reintroduction
Integrated internal feed agitation for gentle mechanical dispersion
Inlet temperatures as high as 750 C.
Roto-Flash drying applications are most commonly found in the chemical industry, including materials such as:
Silica
Organic or inorganic pigments
Titanium dioxide
Many others
The drying chamber is a vertical cylinder. It has an annular air inlet and an axially mounted rotor. Drying air from a supply fan enters the air heater, most often heated by a direct fired gas burner, and enters the hot air inlet plenum tangentially. This tangential inlet, together with the action of the rotor, causes a whirling gas flow inside the drying chamber.The feed material is discharged from an upstream process device into the feed vat, which is mounted onto load cells for process control purposes. A low-speed agitator breaks up the cake to a uniform consistency and gently presses it down into a feed screw. As the feed material is extruded off the end of the screw and enters the drying chamber, it becomes coated with dried powder. The powder-coated lumps fall into the Roto-Flash chamber and are kept in motion by the rotor while disintegration takes place. When dry, the friable surface material is abraded off by a combination of particle attrition and the mechanical action of the rotor, resulting in a balanced agitated fluid bed, which contains all phases from raw material to finished product.
Roto-Flash drying applications are most commonly found in the chemical industry, including materials such as:
