(Vacuum/pressure) nutsches Merto-Fil

(Vacuum/pressure) nutsches are suitable for filtering liquids with a high solids content in batches, especially when sophisticated post-treatment of the solids is required. In this process, the liquid is mechanically separated through a permeable filter layer. This can be done either under vacuum using atmospheric pressure or under pressure or by a combination of vacuum and pressure. A special agitator improves the efficiency of the filtration and enables the solids to be removed mechanically. The horizontal filter bottom forms an even filter cake, which ensures optimal dewatering of the solids.

Our Merto-Fil range of (vacuum/pressure) nutsches are self-contained, vacuum-tight and pressure-resistant housings. They have a horizontal filter bottom, which can be released by screws or a quick release fastener, and a height-adjustable vertical agitator. Various filter materials (cloth, screen) with different mesh sizes/pore sizes can be attached to the filter bottom.

The solid-liquid mixture enters the feed chamber via an inlet connection. Filtration starts in vacuum mode by suction or in pressure mode by pressing off the filtrate, possibly while the agitator is rotating. A filter cake forms on the filter material, which is smoothed out during operation by lowering the agitator. This not only avoids breaking open dry cracks, but also reduces vacuum losses and greatly reduces the residual moisture of the solids. Removal of the solids begins by turning the agitator in the opposite direction. By lowering the agitator further, the filter cake is removed layer by layer with the slanted blades and discharged through the filling opening.

In addition to the standard (vacuum/pressure) nutsches of the Merto-Fil series, we can also design customised nutsches according to your requirements.

Furthermore, we offer you the opportunity to check the feasibility of your requirements in our modern equipped technical centre. Here we work together to develop the optimum process for your specific applications.

Technology centre


The machine is designed so that the following working procedures can be done:


techn. details:

Temperature: -10 – 200°C

Pressure range: -1 – 10 bar

Filter area: 0.12 – 12 m²

Volume: 50 – 12,000 litres


The mixture from the feed tank is filled into the (vacuum) pressure nutsch and then pressed through the filter medium. The resulting filtrate enters the filtrate receiver, where it can be observed through a flow-through sight glass. If vacuum filtration is used, the necessary negative pressure is created with the help of a vacuum pump. It is important to avoid an excessive vacuum, as the vapour pressure of the filtrate must be taken into account. This can be achieved by incorporating an adjustable vacuum reducing valve.

In order to optimally utilise the full performance and specific characteristics of our (vacuum/pressure) nutsche filters, it is possible to combine the filtration process with a washing process. This process serves either to recover the valuable filtrate almost loss-free or to clean the filter cake from adhering impurities from previous reactions. In this process, a steady supply of washing liquid is fed through a ring brewer tube, which flushes the solids one or more times as required.

During the washing process, the solid residues can be effectively mixed with the washing liquid using an agitator. Once the washing process is complete, the washing liquid is either sucked out or squeezed off and the cleaned solids are discharged.

Also for extraction, i.e. to isolate individual components from the mixture with the help of a suitable solvent, effective nutsch filters are available (under vacuum or pressure). For this purpose, the mixture of substances is placed on the filter surface together with the solvent. Mixing by means of an agitator reduces the need for solvent and effectively shortens the separation times.

Our (vacuum) pressure nutes prove to be suitable equipment for the working process of batch crystallisation. In this process, separation is carried out by means of contact or vacuum cooling. When contact cooling is used, heat exchange takes place through a double jacket (special design), whereas with vacuum cooling, cooling is achieved through expansion evaporation. Regardless of the method chosen, the additional use of stirring leads to an improved distribution of heat. This has the effect of keeping the crystal particles in a suspended state, which additionally increases the efficiency of the process.

Since the feed chamber is located in a closed vacuum housing, the (vacuum) pressure nutsch can also be used partially as an agitator dryer according to one of the previously mentioned methods. If such an application is intended, it is possible to attach a heating device to the cylindrical part of the feed chamber. The agitator ensures continuous mixing of the dry material. To accelerate the drying process, superheated steam, hot air or inert gas can be passed through the filter cake.

Advantages of the Merto-Fil nutsches

Advantages of (vacuum) pressure nutsches compared to conventional filter presses and centrifuges:

  • Uncomplicated automated feeding
  • Execution of the process in a closed system
  • Suitable for processing hazardous and noxious substances
  • Can be used as a reactor or crystalliser
  • Combination of filtration and drying in a single unit possible
  • Temperature control (heating and/or cooling) possible
  • Multiple thorough washing of the filter cake with a variety of washing liquids with minimal liquid consumption
  • Versatile options for combining different processing steps
  • Automation of the process through PLC system control
  • Availability of versions according to ATEX and GMP as well as made of various materials (stainless steel)

Sector-specific applications:

The (vacuum/pressure) nutsches of the Merto-Fil series have proven themselves in numerous industries and fields of application. Special solutions have also been successfully used by our customers for many years.

  • Polymers
  • Pigments
  • Active ingredients
  • Recovery of caffeine from green coffee
  • Acetic anhydride
  • Supensions
  • Amoxicillin
  • Antibiotics
  • Biotechnology dyes
  • Crystalline essences and flavours
  • Natural extracts
  • Omeprazole
  • Penicillin
  • peptides
  • synthetic vitamins
  • Plant extracts
  • Meat extracts
  • Flavours and fragrances
  • Additives
  • Colourings
  • Vitamins