FRITSCH PULVERISETTE 5/4 classic line - Manual (Page 38)

Depending on the application, the grinding duration should be adapted
to the development of heat in the bowls. The temperature inside the
bowls is 20 - 30 °C warmer than the outer casing temperature.
CAUTION!
The maximum temperature of the grinding bowl outer
casing is 100 - 110 °C (agate, max. 70 - 80 °C).
The grinding duration is therefore based on the maximum
bowl temperature. The grinding duration at which the tem-
perature is not exceeded depends on the material, ball, and
speed. For this reason, the user should determine it
through experimentation.
Reference value
When grinding at high speeds and with large bowls, a grinding duration
of one hour (depending on the temperature) should not be exceeded.
Then allow the unit to cool down for half an hour to one hour.
NOTICE!
– Observe the warming up of the grinding stock.
– A longer running time may require pause times for
cooling down.
– Check that the tensioning device is firmly connected
when switching on again after a cooling-down phase.
NOTICE!
If bowls are removed during a grinding pause, check that
they fit correctly before the device is switched back on.
The extent to which the heating up of grinding stock needs
to be observed depends on the sample used in each indi‐
vidual case. Note® A longer running time may also require
a longer pause time for cooling down.
To reduce the grinding time, you can use a grinding bowl and grinding
balls with a higher density, and thus a higher impact energy.
The mill can also run for several hours during low-speed operations for
mixing and homogenisation.
Operation with an external time switch is not possible.
Using the device
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