The new s-Jet® 25 is a small and compact laboratory unit and the logical complement to the proven new stem jet mill s-Jet® series.
With this new development, it is now possible to manufacture nano-particles on a laboratory-scale with dry-grinding.
This System is a combination of spiral jet mill and integrated dynamic air classifier. High finenesses can be obtained with this mill, independent of the load in the air jets. During the development of this plant great care was taken to create a system especially suitable for manufacture of very small amounts and product sample.
The compactly constructed lab-plant includes all necessary components such as dosing, mill, product separation, control unit, fittings and steam generator on a skid. The space required for the assembly of the complete steam grinding plant is only 3 m2, while the maximum necessary height is 2450 mm. All product-contacted parts as well as the assembly frame made of stainless steel. The plant is delivered completely mounted and ready-for-operation. Central connection points for compresses air and electricity, water inlet and-outlet ensure very short installation- and commissioning times. Further requirements were an ergonomic design and easy cleaning, as well as condensation of the waste steam vapors produced during this process. This allows a flexible assembly of the system.
An integrated dynamic air classifier in the housing can be infinitely adjusted to the desired fineness. This guarantees exact adjustment of the grinding parameters and reproducible product quality.
Even the hardest of products poses no problem for this steam mill. In addition, moist products can be ground and dried simultaneously using superheated steam without any additional pre-drying process for inlet.
The new s-Jet® System (steam, superfine)
The increasing interest in finer, dry products has led to the development of economical dry-grinding processes down to the submicron range. The new s-Jet® System (patent pending) is a innovation in a line of consistent developments being made in the area of air jet milling. Final finenesses in the submicron range (example: d50 0.2 µm) can now be achieved by steam jet mill, which was only possible by means of wet media milling process at the past.
As opposed to conventional dry grinding processes with fluidized bed jet mills, the s-Jet® System uses superheated steam as its milling gas.
Compared to air, steam provides considerably higher jet energy. Jet speeds of up to 1,200 m/s can be achieved ( Air about 550 m/s ) and the kinetic impact energy of the particles inside the fluid bed rises fourfold! This allows achieving finer particles in dry–grinding process as opposed to air operations. The higher total energy input leads to a distinctive increase in throughput (more than double the capacity!). Therefore, the throughput of a machine can be increased immensely, without changing the fineness.
Since steam moves at a higher speed of sound than air, the circumferential speed of the current inside the classifier wheel can rise, which in turn influences the acceleration forces effecting the material being classified. This is the decisive step toward classifying particles into the submicron range for the first time, via dry grinding.
- Highest grinding fineness < 150 nm (d50) dry grinding
- Development of new products & applications
- Processing of sticky products
- Optimal product performance
- Highest product purity
- Steep particle size distribution
- Small sample amount possible
- Variable assembly possibilities
- Small amount of space required
- Ergonomic design
- Easy cleaning
- Simultaneous grinding and drying of moist products
- Using superheated steam for the ultra-fine grinding of soft to hard
- Exactly defined maximum particle size through integrated dynamic air classifier
- Reproducible results
The new s-Jet® System is a consequent further development of the air-jet mill based on the Fluidized Bed Jet Mill CGS. Using steam instead of air, a considerably higher jet energy is made available whereby higher capacities and new ranges of fineness (submicron) can be achieved in the area of dry grinding.
Ultra-fine Grinding and Ultra-fine Classifying on a Laboratory Scale
NETZSCH Trockenmahltechnik GmbH, one of the global leading companies in the area of dry product processing, is part of the Business Unit Grinding & Dispersing of the NETZSCH Group. Customers profit from our comprehensive experience potential and our diverse machine program, ranging from laboratory- and production machines to complete production lines. Fine impact mills, classifying- and jet mills as well as fine-cutting mills and high-efficiency fine classifiers made by NETZSCH are mainly used in the application areas chemistry, inorganic materials/minerals, ceramics and life science for pharma- and food applications.
From the generation of adiabatic energy through to the breakthrough in nano range particles, a joint development in economical jet milling of industrial minerals and dry grinding in the sub-micron range is described by Dr. Roland Nied.
s-Jet® System: A recent development in size reduction technology can improve the micronization process by a factor of 10.
Economical Jet Milling of Inorganic Materials and Dry Grinding into the Nanometer Range
Steam is Power
A new method of grinding for jet mills that allows finenesses in the submicron range to be obtained was described in the April 2010 issue of cpp in an article headed “Economical using steam”. Such finenesses had until then been unattainable with dry grinding. This established process, known as the s-Jet® system, is meanwhile operating successfully in numerous applications.
Micronization is the miniaturization of particles by jet milling with compressed air or other gas to a range of 2-200 microns (µm). For most dry grinding processes, 2 µm is the practical limit of the technology...
The interest in finer, dry products has led to the development of more efficient jet milling processes. The first part of the paper describes the thermodynamic basic principles for generation and application of steam, and compressed gases. Practical experience has shown that in the aspired fineness range stabilization during grinding provides an enormous potential for improvement. Some selected examples demonstrate that the energy requirement can be reduced by a factor of more than two by suitable choice of stabilizers.
Micronization is the miniaturization of particles by jet milling with compressed air or other gas to a range of 2-200 microns (µm). For most dry grinding processes, 2 µm is the practical limit of the technology. Nanonization is the miniaturization of particles by jet milling with superheated steam. By using superheated steam as the grinding gas, a fluidized bed jet mill with this revolutionary technology, can produce dry powders with median particle sizes in the range of 130 nanometers (nm) with 100% of the distribution finer than 400 nm. This patented new technology, known as s-Jet®, represents a quantum leap in particle size reduction by a dry grinding process and improves the jet milling process 10-fold. s-Jet® uses steam to produce superfine particles; therefore the new term – Nanonization!