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PULVERISETTE 7
4.5 Mass Balance
To balance the mill, always clamp a corresponding heavy grinding bowl with lid
and sealing into the opposed bowl holder. This second grinding bowl may be
empty (without balls and sample).
Under certain operating conditions, the machine may creep along the sur-
face on which it is located or mounted. This may be due to a difference in
weight of the grinding bowls.
4.6 Grinding Time
In accordance with the application, the grinding time should be adapted to the
heating of the bowl. The temperature inside the bowl is about 20-30°C higher
than the outside of the grinding bowl.
The max. temperature at the outside walls of the bowl is about 100-110°C
(Agate max. 70-80°C).
The grinding time is determined by this temperature. The grinding time
wich does not exceed this temperature depends on the sample material,
the balls und the speeds. For this reason the grinding time has to be de-
termined experimentally by the user.
clue
In the case of grinding at high speeds the grinding time should not exceed 1
hour (temperature-dependent). Then allow to cool for 0.5 to 1 hour.
Pay attention to the heating of the material;
In the case of extended running times, if necessary set a break time for
cooling.
Before switching on again after a cooling phase, check that the clamping is
secure.
To reduce the grinding time, choose grinding balls of a higher density.
In the case of operation for mixing and homogenisation at low speeds, the mill
may run for several hours without harm being done. The machine cannot be
operated with an external timer.
4.7 Control Panel
Switch on the main switch at the rear of the machine.
he green POWER SUPPLY standby display on the control panel will light up.
4.7.1
Setting the Speed
ROTATIONAL SPEED control panel area
Press or press and hold down the "+" or "-" button.
The speed can be selected in steps of 10 rpm between 100 and
800 rpm.
During operation, the actual speed is indicated; pressing the "+" or "-"
button will cause the specified speed to be shown temporarily.