FRITSCH PULVERISETTE 14 - Manual (Page 39)

7. Sample feeding with the LABORETTE 24 is carried out as described
in Ä Chapter 6.9 ‘Continuous feeding of source material’
on page 33.
When the sample bottle is 2/3 full, stop the comminution.
To do this, switch off the PULVERISETTE 14 and the sample
exhaust system. Then empty the sample bottle.
If comminution is not stopped when the bottle is 2/3 full, the effective-
ness of the classifier is impaired and material will gradually clog the
upper part of the filter of the sample exhaust system.
If the vortex of comminution material in the collection bottle slows
down, this means that the air throughput or air flow rate has decreased:
n the sample amount fed is too large
n the grinding chamber is overfilled or
n the sieve ring has to be cleaned and / or
n the filter of the exhaust system has to be cleaned.
Small amounts of fine dust that cannot be separated by the
cyclone separator collect on the upper filter of the sample
exhaust system. Clean the filter from time to time by vac‐
uuming or blowing out.
6.13 Factors with an impact on grinding
The smaller the feed rate of source material, the larger the share of fine
particles and the circulation of air. The mechanical and temperature load
on the mill decrease.
Higher speeds shorten the grinding time and increase the share of fine
particles. The mechanical and temperature load on the mill increase
exponentially with increasing speed.
The smaller the perforation of the sieve, the slower the sample has to be
fed and the longer the milling time. The noise level decreases with finer
perforation.
Effective cooling (e.g. by using the filter system or source material
exhaust) always has benefits for milling and mill.
Source material feed rate
Speed
Size of sieve perforation
Cooling
Using the device
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