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.

Nauta® conical screw dryer Nauta® conical screw dryer Nauta® conical screw dryer Nauta® conical screw dryer Nauta® conical screw dryer

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.

Conical screw dryer

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
  • Crystallisation
  • 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.

  • Multi-purpose and multi-processing
  • Efficient drying of loose powders to heavy pastes and viscous liquids
  • Batch volumes ranging from 5 to 22,000 litres
  • No segregation and no product degradation
  • Full compliance with international standards (FDA, cGMP, EHEDG)
  • Automated cleaning solutions with our patented CIP filter and CIP skids
  • Sterile processing (SIP)
  • Interchangeable screw agitator for dryers larger than 20,000 litres

Nauta conical screw dryers are available in many sizes and are custom made to suit your application. A number of models with their typical characteristics are described below. Please note that these values are indicative only. Detailed information on all models is available on request.

Model (water filling)[l]5805001000500012,00022,000
Height [mm] 1420 2660 3920 4460 6840 8450 9950
Width [mm] 600 900 1470 1720 2710 3730 4290
Net volume (powder filling) [l] 4.3 68 430 840 4500 12,000 22,000
Jacket surface area [m²] 0.13 0.69 2.84 4.58 13 25 33
Max. evaporation water * [kg/h] 1 5 25 35 100 190 250
Max. evaporation ethanol * [kg/h] 3 12.5 60 85 250 400 600

* Jacket surface temperature T=50°C

Laboratory & pilot vacuum dryers

Our laboratory & pilot vacuum dryers are small vacuum drying systems that have been specially developed for use in laboratories. They are multi-purpose systems for wide-ranging applications.

The complete systems, including all of the necessary ancillaries, are built on stainless steel skids with wheels. They are very suitable for process development activities, experimental purposes and for fine-tuning for optimal process parameters. The laboratory dryers are available from 5 litres to 20 litres and the pilot dryers from 40 to 120 litres.

Standard industrial dryers

Our industrial dryers are available in sizes of up to 22 m³. They are designed and built according to industry standards such as Stoomwezen, PED, TÜV, Lloyd’s, ASME, Afnor, ISPLE etc. and are available in all grades of stainless steel, Monel, nickel, titanium, Hastelloy, etc.

Bespoke systems

Hosokawa Micron has 90 years of experience in designing and manufacturing vacuum dryers and turn-key vacuum drying systems. This experience in designing complete installations with process guarantees and validation makes us a valuable partner for the realisation of total powder processing solutions. Our expert design and engineering team would happily work with you on a tailor-made design for any of our dryers or drying system.

Our expert design and engineering team would happily help you specify the right ancillary equipment to compliment the Nauta® conical screw dryer. These ancillaries may include:

  • Vacuum filter
  • Sampler
  • Heating/cooling skid
  • Ball segment valve
  • Lump breaker
  • Liquid injection
  • Controls
  • CIP/SIP skid

How can we help you?

To learn more about our powder process equipment, contact us:

Related Applications

Hosokawa Micron designs and manufactures mixing, drying and agglomeration equipment and systems for the powder and bulk processing industry.

Steam treatment of food products

Learn more


Learn more

Chemically Produced Toner

Learn more


Learn more

Active Ingredients (API)

Learn more

Nuclear applications

Learn more


Learn more


Learn more

Additive Manufacturing

Learn more


Learn more