Gentle mixing of free flowing, fragile and/or segregative powders
Mixing of pastes and slurries
Liquid addition to powders and pastes
Temperature treatment, cooling/heating
Reactor vessel in pressurised conditions/vacuums
Live hopper for sticky or segregative products
Very energy-efficient
Consistent mixing quality at fill levels from 10 to 100%
Available in volumes from 5 up to 100,000 litres
Low-Shear Batch Mixer
The Nauta mixer is a highly efficient, low-shear batch mixer specifically designed for processing segregative, free-flowing powders and pastes. It ensures gentle mixing while maintaining maximum accuracy without distorting the product, making it ideal for delicate materials and processes that demand precise results.
Beyond mixing, the Nauta mixer can also be used for heating, cooling, drying, and moistening. Additionally, it can function as an agitated hopper to feed dryers, such as fluid beds, with or without back mixing.
As a pioneer in mixing technology, the Nauta mixer is named after Mr. J.E. Nauta, who developed the first conical screw mixer in 1939. His company, 'Nautamix,' was acquired by Hosokawa Micron in 1982. Since then, Hosokawa has continuously further developed the Nauta mixer, leading to numerous innovations such as the Intensifier, which enhances mixing efficiency. Thanks to its high reliability and excellent performance, the Nauta mixer is a market leader in mixing technology and is used worldwide by thousands of customers for a wide range of applications.
Nauta is a registered trademark (®) of Hosokawa Micron B.V.
Principle of Operation
The Nauta mixer is a convective mixer, utilizing a combination of axial, radial, and tangential mixing mechanisms to achieve thorough and precise results.
The mixer is loaded from the top, either manually, using a Big Bag, or via pneumatic or mechanical methods. The rotating, cantilevered (free-hanging) mixing screw conveys the product from the bottom of the vessel to the surface. Suspended from the orbital arm, the screw rotates along the inner vessel wall, promoting convective particle mixing and shear. As particles flow downward and are recirculated by gravity within the conical vessel, their speed increases as the vessel diameter narrows. This combination of actions delivers fast and intensive mixing with low power consumption and high accuracy.
The mixing duration depends on product characteristics, desired mixing accuracy, and batch size. The screw operates at an average speed of 70 rpm, while the orbital arm rotates at 1 to 2 rpm. The screw's tip speed can range from 0.5 to 2 m/s, making the mixer suitable for all ATEX zones.
Once the mixing process is complete, the product is discharged through a valve located at the bottom of the mixer, either manually or automatically, and the product can then be packaged or directed to the next processing step, such as tableting, extrusion, or sieving. The outlet design ensures complete emptying, eliminates the need for manual cleaning, and minimizes the risk of cross-contamination between batches.
Applications
Nauta mixers are suitable for a broad range of processing activities across industries such as pharmaceuticals, food, plastics, metals, minerals, nuclear, chemicals, pigments, and coatings. Key applications include:
Gentle mixing of free-flowing and segregative powders, pastes, slurries and liquids
Moistening of powders
Coating
Granulation
Heating / Cooling
Drying via heat input under atmospheric conditions or in combination with vacuum and possible liquid recovery
Coating of solids with liquids (using an intensifier)
Models
The Nauta conical screw mixer is available in many sizes. A few sizes with their typical characteristics are described below. Please note that these values are indicative only. Detailed information is available on request.
Size
[l]
500
1000
2000
5000
10,000
20,000
50,000
100,000
Vessel diameter
[cm]
145
180
210
285
355
440
570
700
Vessel height
[cm]
175
225
280
380
500
600
825
900
Height incl. motor
[cm]
225
290
350
470
620
730
965
1030
Typical motor power
[kW]
2.2
5.5
7.5
15
22
37
55
90
Nauta® Minimix
Following the concept of the famous classical Nauta mixer, this small scale model has been made available for lab environments. Although small in size, the advantages remain: high mixing accuracy, gentle mixing, complete discharge and flexible filling range. The Nauta Minimix is able to provide reliable results from only 0.3 litres powder content.
Cleaning
At Hosokawa Micron, we understand the importance of choosing the right cleaning method for your conical screw mixer. Our approach combines smart design with your specific manufacturing processes to ensure optimal cleanability. Selecting the best cleaning method depends on factors such as the material being processed, contamination risks, and industry regulations (e.g., food or pharmaceutical standards). A key challenge in any cleaning process is determining when the equipment is truly clean and ensuring consistent, reliable results.
We offer three categories of cleaning solutions tailored to your needs:
Dry Cleaning: For powders or materials sensitive to moisture, involves brushing, vacuuming, or air-jet cleaning.
Wet Cleaning: Using water or solvents, often through CIP (Clean-in-Place) systems, ideal for removing residues but requires drying.
Sterilization: For sensitive applications (e.g., pharma), may involve steam or chemical sanitizers.
Your choice of cleaning method depends on contamination risk, ease of access for cleaning, and whether full disassembly is needed.
Hosokawa Micron provides a range of fixed or removable cleaning systems for automatic (wet) cleaning, using gas or liquid agents, including custom CIP systems and drying skids. For manual wet cleaning, we offer access doors, platforms, and manual spray lances to ensure safe, easy access to all areas requiring cleaning.
Incorporating cleanability is an integral part of our mixer design process. Our specialists are ready to help you incorporate cleaning solutions from the very start, ensuring efficiency and sustainability, helping you reduce costs, protect the environment, and achieve excellent cleaning results.
Ancillaries
Enhance your Nauta conical screw mixer with a range of ancillary options tailored to fit your process needs. Hosokawa Micron provides customized solutions designed to maximize productivity and efficiency in your production plant. Our team of skilled engineers is ready to guide you in selecting the perfect ancillary equipment for your application, ensuring optimal performance and seamless integration with your mixer.
Hosokawa Micron has been developing innovative solids processing systems for more than a century. As a result, we can draw on an unparalleled amount of know-how when designing new powder mixing systems. In a powder mixing system, the equipment, process steps and interacting parameters must all work together as an integral solution in order to ensure the optimal functionality, quality and efficiency of your total system. That's why we carefully select, configure and integrate all the components and processes when designing a powder mixing system.
Our Test and Process Development Centre in the Netherlands offers unique possibilities for testing your product to determine the most efficient process, system or plant prior to final design. We can provide laboratory-level as well as production-sized trials.
Whether you wish to test a single machine or a complete powder processing system, the same skilled and experienced staff are here to help ensure that your requirements are met, and that you are entirely satisfied with the results.
We offer process equipment and technologies from individual units to large scale bespoke system solutions. Our principle is to deliver high performance yet affordable solutions that meet our customers' demands and long term challenges.
Talk to Our Experts
Let our process specialists help you develop the optimal solution for your powder and bulk solids processing – from the first trial in our test centre to a full-scale industrial production system.
Hosokawa Micron B.V. is committed to sustainable and responsible process technology. Our ISO 14001 certification covers key environmental aspects such as air, soil, energy, waste, water, noise and hazardous substances. With an EcoVadis Silver Medal, we rank among the top 15% of EcoVadis-rated companies in the special machinery industry.
