A Nauta vacuum dryer is a conical screw dryer used for drying powders, granules, pastes and slurries — especially products that are heat-sensitive, contain solvents, or are toxic or explosive. It also supports vacuum processes such as crystallisation, heating/cooling, sterilisation and de-aeration.
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BATCH DRYERS
for Powders & Bulk Solids
Nauta® Vacuum Dryer
Conical Screw Dryer
The Nauta conical screw dryer is a highly versatile vacuum dryer designed for drying powders, granules, pastes and viscous slurries — especially when these products are heat-sensitive, contain solvents, or are toxic or explosive.
It is particularly suited for products that become heavy or sticky during drying, and can also be used for a wide range of vacuum operations such as crystallisation, sterilisation, heating/cooling, de-aeration, and solid-liquid separation.
Key Benefits
- Multi-purpose and multi-processing conical screw dryer
- Efficient batch drying from free-flowing powders to heavy pastes and viscous liquids
- No segregation or product degradation
- Interchangeable screw agitator for dryers > 20,000 L
- Full compliance with industry standards including FDA, cGMP, EHEDG
- Automated cleaning with our patented CIP solutions optional
- Sterile processing (SIP) optional
- Available in volumes from 5–22,000 L
Principle of Operation
The Nauta conical screw dryer is a convective batch dryer with high thermal efficiency. A cantilevered (free-hanging), rotating screw conveys product from the bottom to the surface. Suspended from an orbiting arm, the screw moves along the conical vessel wall, generating axial and radial motion for efficient mixing.
Thermal energy is supplied via a heated jacket, which can be fed with steam, thermal oil or water. This enables rapid heat transfer into the product, enhanced by continuous mixing.
A vacuum environment lowers the boiling point of solvents and moisture, making the Nauta vacuum dryer ideal for heat-sensitive materials. Vapours are extracted through a dust filter at the top of the vessel, preventing product carryover into the vacuum system.
A condenser with solvent recovery tank is included and can be placed before or after the vacuum pump depending on solvent characteristics. The moisture content of the product can be controlled by monitoring the weight of the condensate or by using a Hosokawa Sampler to take samples from the product inside the dryer under vacuum.
Process Flexibility
The Nauta vacuum dryer is primarily designed for vacuum drying of solid based materials, but also supports other thermal and vacuum processing applications, such as:
- Mixing and drying under vacuum
- Alkalisation, solid-gas reactions
- Cooling of solids and liquids
- Crystallisation
- De-aeration of pastes and liquids
- Sterilisation
- Wet agglomeration and granulation of solids
Combining multiple process steps in a single vessel saves space, labour and capital investment.
Models & Capacities
Indicative values; performance depends on product properties and process parameters. Detailed specifications available on request.
| Size (water filling) | [L] | 5 | 80 | 500 | 1,000 | 5,000 | 12,000 | 22,000 |
|---|---|---|---|---|---|---|---|---|
| Height | [mm] | 1,420 | 2,660 | 3,920 | 4,460 | 6,840 | 8,450 | 9,950 |
| Width | [mm] | 600 | 900 | 1,470 | 1,720 | 2,710 | 3,730 | 4,290 |
| Net volume (powder filling) | [L] | 4.3 | 68 | 430 | 840 | 4,500 | 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: 50°C
Our industrial dryers are engineered and manufactured in compliance with global industry standards such as Stoomwezen, PED, TÜV, Lloyd’s, ASME, Afnor and ISPE. They are available in all grades of stainless steel, Monel, nickel, titanium, Hastelloy, etcetera.
Options & Ancillaries
Enhance your Nauta vacuum dryer with a range of ancillary options to fit your processing requirements. Hosokawa Micron provides customised solutions to maximise performance and productivity. Our experienced engineers support you in selecting the optimal ancillary equipment for your application — ensuring smooth operation and long-term efficiency.
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Laboratory & Pilot Vacuum Dryers
Hosokawa Micron’s laboratory and pilot vacuum dryers are compact systems designed for research, development and process optimisation. Built on mobile stainless-steel skids, each unit includes all necessary ancillaries for independent operation. These multi-purpose dryers are ideally suited for experimental work, scale-up trials and fine-tuning of process parameters. Laboratory models are available in capacities from 5 to 20 litres, while pilot units range from 40 to 120 litres.
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Bespoke Drying Systems
With over 100 years of experience in solids processing, Hosokawa Micron has the in-depth knowledge and engineering expertise to design fully integrated, tailor-made drying systems. We understand that optimal performance depends on the precise interplay between equipment, process steps and control parameters — which is why we carefully configure and align every component to function as part of a seamless, high-performance solution.
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Video
This video takes a deeper look at Nauta Mixers & Dryers, their principle of operation, history and development of Nauta technology, benefits, features and functions as well as common mixing and drying applications.
Energy-Saving Vacuum Dryers
Drying is responsible for more than 15% of energy consumption in modern industrial processes. This makes energy efficiency an important factor when designing a conical dryer. Hosokawa Micron is an expert in developing advanced conical screw dryers and we put a lot of our own energy into developing screw dryers that will save you energy!
Test Before You Invest
Before investing in new equipment, test your materials under real process conditions at our Test & Process Development Centre in the Netherlands. Our experienced specialists help you determine the most efficient mixing, agglomeration or drying process, from laboratory trials to full-scale production testing.
Whether you want to evaluate a single machine or a complete processing line, we provide tailored testing and process optimisation to ensure reliable scale-up and proven performance. We also have rental equipment available for batch drying.
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Talk to Our Experts
Let our specialists help you configure the right vacuum dryer for your powders and bulk solids — tailored to your process and optimised for efficiency, safety and product quality.
Applications
The Nauta vacuum dryer is ideal for a wide range of products. Here are a few examples:
FAQ – Nauta® Vacuum Dryer
What is a Nauta Vacuum Dryer?
How does a Nauta Vacuum Dryer work?
A free-hanging screw, suspended from an orbiting arm, rotates along the conical wall of the vessel. This motion lifts product from the bottom to the top, generating axial and radial movement for efficient mixing. Heat is applied through a jacketed vessel wall, while the vacuum environment enables low-temperature drying. Vapours are removed via a dust filter and solvent recovery system.
What materials can be processed in the Nauta Vacuum Dryer?
The Nauta dryer handles a wide range of materials, including free-flowing powders, cohesive pastes and viscous slurries. It is suitable for applications in pharmaceuticals, chemicals, fine chemicals, food ingredients, minerals and more — especially where gentle handling and controlled drying conditions are required.
What are the advantages of the Nauta Vacuum Dryer?
It offers efficient batch drying with minimal product degradation, even for challenging materials. The dryer combines mixing and drying in one vessel, supports low-temperature drying under vacuum, and ensures excellent heat transfer and homogeneity. It is scalable, CIP/SIP capable, and meets cGMP and EHEDG standards.
What capacities and sizes are available?
The Nauta vacuum dryer is available in volumes from 5 litres to 22,000 litres. Laboratory models are ideal for R&D and process development, while industrial models are built for large-scale production. Custom-built solutions are also available based on your process requirements.
Can the Nauta Vacuum Dryer be used for sterile or solvent-based processes?
Yes. The Nauta dryer can be supplied in a sanitary, GMP-compliant design with optional SIP (Sterilisation-In-Place), solvent recovery, and integration with PAT tools. It is suitable for sterile processing in pharmaceutical and chemical environments.
Sustainable Process Technologies
Hosokawa Micron develops powder processing systems with a focus on energy efficiency, process optimisation and long-term operational performance. As an ISO 14001 certified company with an EcoVadis Silver Medal, we support more sustainable powder and bulk solids processing.
