This high efficiency air classifier was developed for ultra-fine, sharp separation, and is often used in conjunction with grinding plants.
The optimized classifier wheel geometry produces the finest cut points and high yields that have not been possible with production scale conventional air classifiers with only one classifier wheel.
The special dispersion zone directly in close proximity to the classifier wheel uses clean gas to efficiently disperse the material to be classified.
The machine can be cleaned thoroughly, in short time when product or batches are changed, due to its highly accessible internal arrangement.
- Finenesses up to d97 2.5 µm (based on limestone)
- High efficiency classifier with horizontal shaft
- Welded classifier housing with hinged door provides very good access for fast, easy cleaning and maintenance
- Spiral housing for optimum coarse material orientation
- Guide vane ring with adjustable vanes for efficient dispersion of the feed product prior to classification
- Classifier wheel with exchangeable, 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 fine fraction
- Classifier shaft seal rinsed by compressed gas to protect the bearings
- Bearing of the classifier shaft is permanently grease sealed or oil lubricated for hot gas applications
- Extremely sharp separation for improved fines extraction
- Highest finenesses and maximum throughput achievable with just one classifier wheel
- Even load of the classifier wheel through rotationally symmetrical design of the machine
- Very good access for fast, easy cleaning and maintenance
- Reproducible results
- Optional designs available: pressure shock resistant, gas tight, wear protected
Brochure
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.
For glass products, ground with dry ball mills or other mechanical Fine Mills the CFS/HD-S High Dispersion Air Classifiers can be used to remove coarse grit and provide a steeper Particle size distribution (PSD) more similar to a jet mill. Also, in some circumstances, fines removal may be desired, also to provide a steeper PSD.
Typical toner products have a D50 in the range of 5 µm – 7 µm. NETZSCH Trockenmahltechnik GmbH entered the field of toner processing with the development of the CGS Jet Mill in the 1990’s followed by the CFS/HD-S High Dispersion Air Classifier a few years later.
NETZSCH has developed new methods in wet and dry processing which enable a mineral processing that matches the requirements of current and future markets.
As the global leader in particle-reduction machinery, NETZSCH offers the technology and machinery to provide true drug development solutions.
Our long-term experience with a diversity of products in these fields, is available for your toll grinding needs.
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.
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.
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.
