Fritsch PULVERISETTE 6 Classic, Operating Instructions Manual, Page: 34 / 70

6.4.4 Number and size of the balls
NOTICE!
It is not recommended to mix balls with different diam-
eters and/or materials (bowls and balls must always be
of identical material!). If balls with different diameters
are used, increased wear and damage to the grinding
elements is to be expected.
You can find the recommended number and size of balls
in
Ä
Chapter 6.1 ‘Choice of grinding bowls and grinding
balls’ on page 27.
Larger balls are used for pre-crushing. (See Ä Chapter 6.1.2 ‘Recom-
mended number of balls per grinding bowl (independent of the material
quantity)’ on page 30).
To increase the proportion of fine particles, the large balls need to be
replaced by smaller ball sizes during the course of the grinding process.
6.4.5 Weight of the balls (type of material)
A higher mass (specific weight) of the grinding balls accelerates grinding.
(see table in Ä Chapter 6.1 ‘Choice of grinding bowls and grinding balls’
on page 27).
6.4.6 Dry grinding
DANGER!
Dust explosion!
There is a risk of spontaneous combustion especially for
very fine metal oxides and a thus resulting dust explo-
sion. Mind the external temperature and the pressure
that can develop in the grinding bowl during the dry
grinding.
NOTICE!
Dry grindings need to be checked in briefer intervals.
Longer dry grindings, without pauses and checks, can
cause the grinding set to gum up and to become dam-
aged. In particular with agate, the grinding bowl and
grinding balls can become damaged after a short
grinding time.
Using the device
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