Nauta® conical screw dryer
The Nauta® conical screw vacuum dryer is a universal batch dryer suitable for drying materials such as powders, granules, pastes and viscous slurries, especially when products are heat sensitive, contain solvents and are toxic or explosive.
The Nauta conical screw vacuum dryer is capable of handling products that become heavy and sticky during drying and can also be used for vacuum operations such as reaction/crystallisation, heating/cooling, sterilisation, liquid/solid separation and de-aeration.
The thermal energy needed for drying is introduced into the product through a heated jacket that can be heated by various media including steam, hot oil and water. The jacket provides rapid distribution of heat into the product in combination with efficient mixing.
The vacuum inside the dryer allows vapour to be removed at low temperatures, which makes the Nauta conical screw vacuum dryer ideal for drying heat-sensitive products. The vapours are removed through a dust filter fitted on top of the vessel. This then prevents the dust from penetrating into the vacuum system.
The conical screw vacuum dryer is fitted with a condenser with a receptacle for recovering solvents. This condenser can be installed before the vacuum pump, or after it, depending on the characteristics of the solvents.
The moisture content of the product can be controlled by monitoring the weight of condensate or using the Hosokawa sampler for taking samples from the product inside the dryer under vacuum.
Hosokawa conical dryers are designed for vacuum drying of solid based materials, but can be used in a wide range of other applications requiring thermal processing or vacuum treatment of solids, such as:
- Chemical reactions: alkalisation, solid-gas reactions
- Wet agglomeration and granulation of solids
- Sterilisation of products
- Homogenising under vacuum
- Cooling of solids and liquids
- De-aeration of pastes and liquids
This combination of several processes in one vessel offers tremendous savings on investment costs, labour and space.