FRITSCH PULVERISETTE 0 - Manual (Page 9)

2.2.1 Operating principle
The plastic housing contains a solid cast structure with an electronically
controlled electromagnet. Three permanently flexible flat springs carry
the pole plate of this magnet together with the vibratory plate, which is
fastened to it. When the magnet is switched on, the pole plate and vibra-
tory plate are attracted and spring back when it is switched off. The cast
structure and magnet on one side and the pole plate, vibratory plate and
sieves on the other side form a vibratory system.
The different weights of the mortar material or grinding balls change the
natural frequency of the vibratory system. For this reason, it is not
always possible to set the amplitude of the micro mill optimally e.g. with
a constant 50 Hz mains frequency present. The processor-controlled
electronics of the PULVERISETTE 0 micro mill ensure a precisely adjust-
able, reproducible oscillation amplitude. This is achieved by bringing the
frequency to stimulate oscillation closer to the natural frequency of the
system or farther away from it. The desired oscillation amplitude of the
grinding set between 0.1 mm and 3.0 mm can always be achieved - and
with relatively low energy input. Therefore, continuous operation is pos-
sible without heating the sample material and the overall mill system.
The mortar bowl with 50 mm diameter grinding ball (or 70 mm for agate
only) and grinding stock oscillates vertically. This causes the grinding ball
in the mortar bowl to vibrate and comminute the grinding stock by
impact and friction.
2.2.2 Amplitude control
An electronic control circuit guides the oscillation frequency of the PUL-
VERISETTE 0 from a high to a low frequency range. In the meantime, a
measuring system records the amplitude and reports it to the control cir-
cuit until the preselected amplitude is reached.
This amplitude control takes place at regular intervals during the entire
operation. This makes it possible to react to changes in the vibratory
system.
The amplitude of the PULVERISETTE 0 is set manually with the Plus and
Minus key on the control panel and viewed on the lid.
2.3 Obligations of the operator
Before using the of the PULVERISETTE 0, this manual is to be carefully
read and understood. The use of the of the PULVERISETTE 0 requires
technical knowledge; only commercial use is permitted.
The operating personnel must be familiar with the content of the oper-
ating manual. For this reason, it is very important that these persons
actually receive the present operating manual. Ensure that the operating
manual is always near the device.
Safety information and use
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