10 mass balance, 11 grinding duration, 10 mass balance 5.11 grinding duration – FRITSCH PULVERISETTE 7 premium line User Manual
Page 47: Using the device
6.
Push the clamping brackets (10) down until they engage in the
bracket guides (12) provided and can not be moved down any fur-
ther.
7.
The loading position can only be changed if the locking elements
(11) and clamping brackets (10) that are not in their initial posi-
tions and block the milling mechanism reach their initial positions
again correctly.
NOTICE!
After a few minutes of grinding and during the cooling
phases, check that the condition of the grinding bowls is OK
(see Ä Chapter 5.8 ‘Wet grinding (grinding in a suspension)’
on page 38, Ä Chapter 5.9 ‘Handling the grinding bowl’
on page 40 and Ä Chapter 5.9.4 ‘Inserting the grinding
bowl in the grinding bowl holder’ on page 44).
5.10 Mass balance
Planetary ball mills are generally subject to a specific imbalance during
operation. To keep this imbalance as low as possible, all rotating masses
in the system must be balanced as completely as possible.
To ensure optimum mass balancing (imbalance correction) of the device,
identical grinding bowls and identical grinding bowl fillings must always
be used at both grinding stations.
It is quite possible to operate the device with different loads (e.g. dif-
ferent grinding bowl fillings) - however, that will result in a power loss or,
depending on the degree of imbalance, in the device shutting down.
"Please check the imbalance" appears on the display, see
Chapter 5.12.8 ‘Imbalance check’ on page 56.
5.11 Grinding duration
Depending on the application, the grinding duration should be adapted
to the development of heat of the bowls. When grinding at high speed, a
grinding duration of 1 hour (depending on the temperature) should not
be exceeded. Then allow the unit to cool down for half an hour to an
hour.
If a chemical reaction takes place in the grinding bowl, the result may be
the development of a very high pressure in the grinding bowl, without
the temperature exceeding 100°C. The pressure must also be released
when the grinding bowl has cooled down.
Using the device
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