News - NEA POWDER COATING NEWS
NEUMAN & ESSER Process Technology develops a new classifier wheel
In January 2018, all Powder Coating technical managers from German-speaking family owned companies accepted an invitation from NEUMAN & ESSER (NEA) Process Technology and participated in a workshop at the NEA headquarters in Übach-Palenberg, Germany.
The goal of the workshop was to optimize existing grinding systems to meet new market requirements.
In addition to the development and introduction of NEAddiX, which is our improved additive feeding system, NEAPT also worked on the development of a new mill classifier. The objective was to improve on the widely used conical wheel. The end result is a multi-blade classifier wheel that is easier and more effectively cleaned, has a reduced pressure drop and improves product quality by steepening the product Particle Size Distribution (PSD).
The NEAProcess Technology multi-blade classifier wheel and associated system components have been proven as “state-of the-art” in this industry for several years providing the end user with a sharpness of cut and unequaled classification.
An important design consideration as specified by our customers was that the new classifier wheel must fit both the existing classifier wheel shaft and the existing classifier seal air gap purge area. This was a requirement as the customer wanted to be able to change classifier wheels very quickly.
The NEUMAN & ESSER classifier technology design experts developed a classifier wheel which could be provided to a customer for endurance and performance testing within 4 months.
In addition to design studies, CFD analyses were also carried-out in order to predict air and powder flow patterns to determine optimal design considerations for the classifier wheel.
The first design was optimized with respect to cleaning accessibility. Although this initial design showed a relatively low pressure drop, it also showed an uneven flow pattern of air and particles which would have resulted in a poor sharpness of cut. Therefore, a second wheel design was developed with an increased number of classifier blades. This second design achieved a better-balanced flow pattern and had a correspondingly higher sharpness of cut. However, while we achieved the target of a better-balanced flow pattern, the pressure drop increased significantly. Therefore, the objective was then to design a classifier wheel with a low pressure loss as in the first design but simultaneously attain the balanced flow pattern as in the second design. Flow simulation shows that the design goal has been achieved. That is, pressure drop is at the same level as in the first design with a flow pattern similar to the second design. The design of the classifier wheel blades still guarantees good accessibility for cleaning.
We can see the flow lines in the entire mill which are pigmented by the static pressure and also the radial velocity distribution on the external diameter of the classifier wheel.
We have succeeded in obtaining customer references with the new classifier wheel design preventing oversize particles passing into the product stream.
Thomas Gächter, Powder Coating Works Manager at the company KABE in Switzerland, was involved in the development of this new classifier.
At the NEAPT Powder Coating Compact, he was clearly happy with the results.
He stated that “A wheel with considerably reduced cleaning times and separating cuts superior to the conical classifier wheel”.
In addition to classifier wheel geometry, NEUMAN & ESSER Process Technology also works successfully on the selection of new classifier wheel materials of construction.
This enabled us to provide several prototypes of our multi-blade classifier wheel to our customers using specifically selected materials.
These material alloy types may, in particular, provide a genuine alternative for sustainably increasing the durability of the wheel when processing highly abrasive powder coatings in the future.
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Christian Begass
Product Specialist Powder Coating
+49-2451-481-203
christian.begass_at_neuman-esser.de
NEUMAN & ESSER Process Technology
Werkstr. o. Nr., 52531 Übach-Palenberg
