CFS 5 HD-S and CFS 8 HD-S High-efficiency Fine Classifiers

The smallest for the finest


The CFS 5 HD-S and CFS 8 HD-S are effective laboratory classifiers for the sharpest separation ranging up to d97 2.5 µm.

The optimized classifier wheel geometry and best possible material dispersion in close proximity to the classifying zone enable the advancement into material finenesses that until now were not reachable with conventional air classifiers, with maximum separation sharpness and yield!

The user friendly design of the machine housing enables fast, complete cleaning of the machine when product or batches are changed.

The plant is designed to be modular, so that other modules can be added, such as our CGS Fluidized Bed Jet Mill and ConJet® High Density Bed Jet Mill to make a completely versatile laboratory platform.

NETZSCH Laboratory Plants


  • Finenesses up to d97 2.5 µm (based on limestone)
  • Laboratory high efficiency classifier with vertical shaft
  • Classifier housing with hinged door provides very good access for fast and easy cleaning and maintenance
  • Spiral housing for optimum coarse grain orientation
  • Guide vane ring with adjustable vanes for efficient dispersion of the feed material prior to classification
  • Classifier wheel with simultaneously rotating immersion tube to achieve highest finenesses, unlimited adjustment
  • Gap between classifier wheel and fines outlet rinsed by gas for highest possible prevention of oversize material in the fines fraction
  • Classifier shaft seal rinsed by compressed gas to protect the bearings
  • Extremely high degree of separation sharpness and consequently improved fines extraction
  • Even load on the classifier wheel through rotationally symmetrical construction of the machine
  • Reproducible results
  • Shipped ready for immediate operation
  • Can be combined with other machine modules
  • Optional designs available: pressure shock resistant, gas tight, wear protected
Function principle of the laboratory classifier





The NETZSCH High-efficiency Fine Classifier CFS/HD-S works very efficiently due to ist closely defined sharpness of cut and ist very specific product flow.


NETZSCH-Feinmahltechnik GmbH offers mixing, kneading and dispersing machines for low- to high-viscosity products as well as a variety of wet-grinding units for reduction into the nanometer range, tailor-made for each application. When it comes to the processing of dry products by cutting, fine grinding or fine classification, you will find a wealth of experience and an equally varied program of fine-impact mills, classifier and jet mills as well as fine-cutting mills and high-performance fine classifiers.


Ultra-fine Grinding and Ultra-fine Classifying on a Laboratory Scale

Application literature

Application literature

The CFS-HD classifier uses a combination of the free vortex and the forced vortex models to achieve cut points down to less than 2 µm. The classifier rotor has a new design for theoretically constant radial velocity in the vane-free internal area; it is surrounded by a cage of static vanes, creating a steep spiral flow in order to give good dispersion and deagglomeration to the material to be classified.

Application literature

Based on the physical model of classification in vaned rotors, the fundamental difference between the exclusive use of a forced vortex flow (i.e. classification at the outer edge of the vanes) and the combined use of forced vortex/free vortex flow (i.e. classification in the interior vane free area) is derived. The classifier used for the comparison is a CFS-HDS model. Results received from this classifier equipped with a ConVor-wheel with constant radial velocity of the flow in the interior vane free area are compared with results from a classifier wheel designed for classification at the outer edge of the vanes.

Application literature

In the ceramic industry the mechanical treatment of raw materials, processed or finished powders is an important part of many production processes. At the same time the grinding- and classifying processes are also of primordial importance, in order to ensure a range of particle sizes which is usually exactly defined for the particular process. The grinding principle of jet milling has proved itself to be particularly effective for the grinding of ceramic and abrasive materials. They can be ground to high finenesses, with an exact upper particle size limit, in one working step.

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CFS/HD-S High-efficiency Fine Classifier

The requirements of many product applications such as improved separation sharpness and finer cut points, are no problem for the CFS/HD-S range of High-efficiency Fine Classifiers.

Thanks to the maximum predispersion of the product to be classified, the targeted cut point and sharpness of cut can be optimized distinctly.

Available for finenesses from 2.5 to 60 µm (d97).

Machine sizes available for gas volume from approximately 50 to 16.000 Nm³/h.

InlineStar High-performance Fine Classifier

This newest fine classifier was conceived to combine with an upstream mill. The direct integration of the InlineStar classifier behind a mill creates a continuous grinding/classifying plant that reduces the number of required plant components.

Available for separation limits from 2.5 to 60 µm (d97).

Machine sizes available for gas volume from approximately 350 to 2.600 Nm³/h.

CFS 5 and CFS 8 Fine Classifiers

Efficient separation of grain sizes and effective results for both coarse material and fine material separation.

For separation limits from 10 to 250 µm (d97).

Machine sizes with gas volume of approximately 25 to 145 Nm³/h.


The LabCompactPlus was especially designed for use in laboratories - machine (mills or classifiers) are taken up by a swivel arm on the machine base and can be exchanged very easily.