NETZSCH recently made several significant upgrades to their “Zeta” grinding system. The Zeta Grinding System was patented in 1991. NETZSCH’s newest grinding system is called the “NEOS.”
 
The flow of the cooling water in the double jacket of the grinding chamber has been optimized for maximum cooling efficiency. The improvement in cooling efficiency is an essential aspect of the new design of the grinding system. In many cases, the power input into the grinding chamber is limited primarily by the temperature limits of the product.
 
The spacing between the grinding chamber liner and the pegs on the agitator shaft were reduced. As a result, more intensive acceleration of extremely small grinding media is made possible (0.1-0.8mm). This leads to a considerably higher energy density, and also a higher possible power input to the grinding chamber.
 
Consequently, with the same grinding bead size, grinding media density and agitator shaft speed, this means the grinding beads have a higher average kinetic energy. This results in higher shearing stresses on the product, which, particularly in the case of shear-thinning products, leads to a lower viscosity product in the machine.
 
In addition, the diameter of the screen in the grinding media separation system was enlarged. This significantly increased the separation area of the screen. In combination with the viscosity reduction effect, this more efficiently prevents deposits of grinding beads and coarse product fragments at the separation screen.
 
These new features make it possible to use smaller grinding beads (0.1mm – 0.8mm) at considerably higher product throughput rates during grinding and dispersing of various products. With the same fill mass of grinding media in the grinding chamber, the use of smaller grinding media means the number of grinding beads, and thus the number of contacts or stresses per unit time increases exponentially.
 
Higher potential product throughput leads to an increased number of cycles per grinding time, resulting in narrower residence time distribution of the product particles in the grinding chamber. Due to the shorter residence time of the product during one pass through the grinding chamber, from the product feed to the product outlet, and the consequently lower energy input, control of product temperature is facilitated, provided that the grinding circuit is equipped with cooled batch tanks.
 
In addition, the agitator shaft geometry was upgraded, such that the circulation of grinding media is improved without compression in the area of the grinding media separation system, even with very high product throughput rates. This means that with comparable installed motor power and grinding chamber sizes, a higher production capacity can be achieved. Due to the ability to use smaller grinding media and the higher product throughput rates, energy requirements are also lower for many applications.
 
Additionally, this leads to reduced wear on the grinding media, less stress on the machine components, and therefore reduced downtime, maintenance, and cost of spare parts relative to the product volume manufactured. 
 
The NEOS grinding system is available for testing in Exton, PA. 
 
For more information, contact Jake Dagen, printing ink application specialist – NETZSCH Premier Technologies, at [email protected].