Everything you need to know about Agitated Nutsche Filter Dryer

Everything you need to know about Agitated Nutsche Filter Dryer


The pilot model of agitated nutsche filter dryer (ANFD) is a multifunctional machine developed for multipurpose manufacturing operations. Promas Engineer’s ANFD is equipped with many features following the latest designs and technology such as, equal capacity filtrate collection receiver under vacuum,  solvent, recovery, compact design, heating arrangements, chilling arrangements,  lifting & lowering. The filters are intended to meet severe cGMP and FDA specifications and demanding requirements for filters used in the manufacturing of pharmaceutical components. All products soaked surfaces are designed without dead spots, smooth inner transitions, and no bolted connections to enable optimum cleanability using CIP systems and optimal inspection following the cleaning process. The filters have an openable filter base providing immediate access to the filter internal components for cleaning and inspection. 

Promas Agitated Nutsche Filter Dryers are designed to meet all the standards and are suitable for a wide range of pharmaceuticals along with fine chemical applications. Our machines are suitable for safe environments, and we have customised designs for cleanroom installation. Agitated nutsche filter dryer (ANFD) is pre-configured equipment for multi-product pilot-scale testing. It is a portable filtering system that is simple to set up and use. When compared to custom-built devices, the standardised design eliminates the expense.

The pharmaceutical sectors rely on the correct technologies and services for filtration, drying, and agitation. Our in-house manufacturing capabilities encompass a wide range of equipment, systems, and features that enable us to provide high-performance and cost-effective operations process solutions.


  • Operation in batches.
  • Drying under vacuum and ultra vacuum are designed with absolute vacuum in consideration.
  • cGMP guidelines were followed in the design.
  • Body and agitator heating/cooling
  • 3 bar of working pressure
  • Operation Temperatures as high as 200 degrees Celsius are possible.
  • Filter cloth may be easily changed.
  • Textiles, synthetics, metal, multilayer, and ceramic filters are all available.
  • Automatic lifting and lowering of the bottom filter
  • The cake is unloaded using the lateral valve.

Working Principle

The general attention to design details makes it possible to simplify the unit validation. The agitator is supported from the top and is externally installed on the stirring, the covers and the shaft seal. The shaft sealing is with a mechanical double screen and a fastened bellow. The agitator’s arms are fitted with a particularly designed surface and push the cake on the reverse clockwise rotation and mix and stir the cake on turning in the reverse direction.

Simultaneous circular and vertical motions of the agitator lead to an extremely efficient mixing of the entire model mass for the blending and drying process. The arms of the agitator are S-formed for better release of the product. All soaked product surfaces are heated to achieve the maximum heat exchange area feasible, resulting in quick drying times and low ultimate humidity.

Operating Sequence

The agitated nutsche filter dryer involves sophisticated valves and hydraulics manipulation such that current installations are fully automated.

Filtration Process

The slurry is poured into the filter, and pressure is applied to displace the filtrate, leaving the cake on the filter media. There is a possibility of segregation in slurries with a wide distribution of coarse fast settling solids and slow settling fines, with the finer fraction settling over the coarse. Because the particles seal the cake and inhibit its production, keeping the slurry suspended with rotating arms during filtration aids in the formation of a uniform cake.

Washing Cake

During the washing stage, the wash liquid is applied to the cake via a spray ring or connections on top of the cover. One of the benefits of using the Nutsche Filter is that it allows you to smooth the cake’s surface before spray washing it, ensuring that the entire bed is uniformly cleaned. In a multi-washing system, washing efficiency can be improved even more if air or gas is not allowed to join the cake, so the wash liquids consistently displace the remedies in a piston-like manner.

Drying Process

Air or gas purges the product during the drying stage until the trapped moisture is decreased to an asymptotic level, at which point the cake is deemed as dry as possible. The cake is smoothed by alternating the rotation of the paddle or auger arms and applying regulated pressure to its surface with the hydraulic system to achieve the lowest possible moisture content. This prevents air or gas from escaping the bed by sealing cracks in the product.

Drying in the Vacuum

Scrape and de-lump the product while slowly rotating and lowering the paddle arms to further reduce product moisture. To make the most of the Nutsche Filter’s drying capabilities, consider heating components like the vessel, filter floor, and paddles.


  • Solvent recovery is exceptionally high.
  • Filtration can be done under a vacuum or pressure.
  • It is possible to sustain a gaseous atmosphere.
  • There will be a significant reduction in the number of people needed.
  • Because solvents are contained within closed systems, no hazardous vapours escape into the atmosphere.
  • Personal safety is ensured, and heat transfer surfaces can be used to keep the filtration temperature constant.
  • Filtrate hold-up in the equipment should be kept to a bare minimum.
  • Minimal staff and no product handling by hand.
  • The Agitator rotates in a clockwise and anticlockwise direction, as well as up and down. This ensures that the cake is thoroughly washed and re-slurred.
  • It is possible to treat toxic and hazardous materials.
  • The purity of the product is preserved.
  • Before releasing the product, it is possible to blend it.
  • Solvents can be used to properly cleanse the product at a low cost.
  • PLC-based automation is offered.
  • Filtration, washing, re-slurrying, and drying are all combined in one fully enclosed, automated machine, resulting in lower capital and operational expenses.
  • Huge quantities can be processed more quickly than with traditional techniques.
  • The number of traditional filtration equipment is also reduced.


Nutsch filter dryers are normally made of stainless steel, specialised alloys, or glass-lined steel because of the nature of the procedures that are frequently done (i.e. very toxic, requiring containment). For applications where chemical inertness and visibility are critical, they are also available in borosilicate glass. The design can be tweaked to meet cGMP, CIP, aseptic, and sterile specifications. As a batch system, the nutsche filter/dryer must be sized according to the capacity of the upstream equipment. Even though some smaller-scale manually controlled nutsche filter/dryers are available, the majority of units are automated and use a combination of electric, pneumatic, and hydraulic systems for actuation. Because the functioning of full-scale machines requires a complex series of discharge valve and agitator system adjustments, the majority of them are fully automated.

The Agitated Nutsche Filter Dryer is slightly elevated equipment developed for solid-liquid separation techniques in the pharmaceutical, chemical, fine chemical, and food industries, using filtering under pressure and vacuum drying. Within the filtered applications, some items are more desirable to be treated in a sealed manner during their manufacturing process due to their specific dangerous or toxic qualities, or simply to prevent cross-contamination. Nutsche Filter Dryers by Promas were created specifically to meet these requirements, ensuring the production of pure, pollutant-free material. The filter dryers are simple and easy to use. They exist in small-batch mobile units that offer a pre-engineered, outlay, and manual operation with the same process capabilities as traditional machines.

Frequently Asked Questions:

In a variety of industrial processes, filtration and drying are crucial tasks. Many applications handle these unit activities independently, but they can also be done in the same unit when it’s more efficient. The Nutsche Filter Dryer combines solid-liquid separation and drying in one unit. You could still have some queries regarding nutsche filtration after you’ve grasped the basics. To assist you better understand the equipment and how it may benefit your process, we’ve put together a list of frequently asked questions.

Q: What is the value of the smoothing stage, aside from closing cracks in the cake?

A:  This operation will aid in the uniform flow of liquid or gas through the filter cake, as well as the elimination of liquid and gas channelling, which reduces displacement washing and gas blow through efficiency. As a result, smoothing can be applied after any filter or wash, particularly the final one.

Q: What is Flexible Output?

A: There are several situations where the desired discharge result is not a dry solid. Agitated nutsche filters dryers have been constructed so that water solids, slurries and even liquids are discharges flexibly.

Q: What factors go into determining the filtering rate and cake depth?

A: The physical features of the product control the filtration rate the most, therefore particle shape, cake porosity, and compressibility must all be considered. Because these parameters are difficult to quantify, studies must be carried out to determine their impact on pressure drop, filtering rate, and cake depth. 

Q: What are the differences between convection and vacuum drying?

A: Drying can be done in two ways; the technique used is determined by the product’s behaviour. A vacuum source, agitation, and dust filter are used in the most popular method of vacuum drying. Vacuum is utilised to reduce the solvent’s temperature, which lowers the average drying temperature. Hot, pressured gas is blasted down through solids and out of filtrate lines during convection drying, which dries the solids ultimately.

Q: What is the objective of filtration washing?

A: In nutsche filtering, there are two methods of washing. Displacement washing, for starters, accomplishes two goals: it eliminates the liquid and its contaminants while leaving the cake intact, and it replaces the old liquid with fresh liquid. The re-slurry process is an optional wash that can be employed when a long contact time between the wash fluid and the particles is necessary or when the displacement wash fails to meet the wash quality requirements.

Q: How do you figure out which filter media is suitable for your application?

A: Nutsche filters come with a variety of filter media, including cloth, single-layer metal screens, and multi-layer sintered metal screens. The media should be chosen according to the slurry’s properties, such as particle size and shape, cake porosity, and compressibility.

Q: What testing methods are suggested for assessing suitable equipment selection?

A: There are a variety of ways to test your product to verify proper filtering. The approach you choose is usually determined by the properties of the product and the specifics of the operation. You can rent scale-up filter/dryers to do small-batch tests; our pocket filter, which allows benchtop filtration testing, is available for purchase or rental; or you can have your product evaluated at our pilot plant facility.

Q: Who tends to make use of nutsche filters and dryers?

A:  The level of containment produced by a nutsche filter dryer can comply with GMP and other health and safety regulations that enterprises frequently confront, thanks to the benefits described above. Nutsch filter dryers are widely employed in pharmaceutical, fine chemical, dye and paint manufacturing, and wastewater treatment applications for these reasons.

Q: What are some of the features of a nutsche filter/dryer?

A: Product isolation, limited operator exposure, reduced product handling, and environmental protection against solvent vaporisation are some of the advantages of employing this technology. A nutsche filter is something to think about if you have a batch operation where containment is an issue and you need a closed system for the safety of the workers.

Q: How do you choose the proper filter size for your application?

A:  The filter should be sized to handle the volume of solids to be treated. The maximum solids height should be equal to or less than the agitator stroke, which is normally 12 to 20 inches, according to a common rule of thumb. The final cake thickness, on the other hand, will be determined by the filter cake’s properties. You’ll need some basic process information, such as slurry volume per batch, wet cake volume per batch, and desired building material, to appropriately size a unit. We can figure out which type and size are best for your process based on these three primary considerations. It’s also crucial to understand the filtration rate, as this can have an impact on the size chosen.

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