With some improvements, the Universal Cutting Mill PULVERISETTE 19 can be optimized. The brand-new patented rotor with notched edges shows its varied potential samples.
Different Versions of the PULVERISETTE 19
The new models utilize different powered motors with variable rotational speeds to gain the correct suitability for each mill in each application. The requirements for the selected instrument then match the user’s application correctly.
For comminution with more power, we endorse the slower PULVERISETTE 19 with a variable rotational speed of 50–700 rpm. The Universal Cutting Mill PULVERISETTE 19 is selected for fine comminution with variable rotational speeds ranging 300–3000 rpm.
Fast or Slow Running – Which is Correct?
When selecting rotational speed, the sample characteristic plays a large role. 
- Component leakages, such as essential oils or moisture
- Feed size and final fineness
- Fracture behavior: brittle, fibrous, ductile or visco-elastic
Figure 1: PULVERISETTE 19 with 300 – 3000 rpm with the new rotor with notched edges made of hardened stainless steel. Image Credit: FRITSCH GmbH - Milling and Sizing
The Advantages of a Continuous System
There is a difference between batchwise and continuous comminution, for example, planetary ball mills and cutting mill with cyclone, respectively. 
The so-called “in process” control is an advantage of the continuous comminution. Therefore sensitive parameters, such as temperature or fine dust development, can be examined and controlled better. If, for example, the output on the cyclone is reduced, this could confirm that adhesions may be present on the sieve cassette, which are favorable due to high temperatures throughout this process.
Throughput is markedly increased when the new rotor with notched edges does not completely close the grinding chamber, therefore allowing optimal airflow, making use of very fine sieves for larger quantities. The effect of samples with residual moisture (foodstuffs, feed or plants) and with a low melting point (plastics) therefore becomes quite decisive in this regard.
Comparison of Temperature and Particle Size
Using the new rotor, with the notched edges made of hardened stainless steel, a sieve cassette of 0.5 mm trapezoidal perforation and a high-performance cyclone separator, hops were comminuted at 3000 rpm.
Figure 2: Comparison of the temperature of the rotors. Image Credit: FRITSCH GmbH – Milling and Sizing
Figure 3: Distribution comparison. Image Credit: FRITSCH GmbH – Milling and Sizing
Larger Throughput and Less Cleaning Effort
Processing difficult samples, such as greasy rabbit feed pellets in significantly larger batches could be possible in future. In the FRITSCH laboratory, the test series conducted with various samples shows an optimistic outcome.
FRITSCH is able to conduct an individual sample grinding if you are interested.
Figure 4: Samples of plastic, wood- and feed pellets: Comminuted with the rotor with notched edges and a sieve cassette with 0.75 mm trapezoidal perforation. Image Credit: FRITSCH GmbH – Milling and Sizing
References and Further Reading
- H.G. Hirschberg: Handbuch Verfahrenstechnik und Anlagenbau: Chemie, Technik und Wirtschaftlichkeit, 1.Auflage 2014
- K. Schwister, V. Leven: Verfahrenstechnik für Ingenieure: Ein Lehr- und Übungsbuch, 2.Auflage, 2014
Produced from materials originally authored by Leos Benes from Fritsch GmbH.
This information has been sourced, reviewed and adapted from materials provided by FRITSCH GmbH - Milling and Sizing.
For more information on this source, please visit FRITSCH GmbH - Milling and Sizing.