FRITSCH PULVERISETTE 0 - Manual (Page 24)

CAUTION!
When handling liquid nitrogen, the Guidelines for Laborato-
ries, BGR 120, in particular Chapter 5.4.6, must be observed
as well as the other relevant guidelines and codes of prac-
tice.
Suitable protective clothing, particularly safety goggles and
heat-resistant gloves must be worn. Only the smallest pos-
sible amounts should be handled. Make sure that the labo-
ratory is adequately ventilated.
1 Upper part
2 Lower part
3 Grinding ball 50 mm
4 Mortar
5 Bent tube ventilation
6 Funnel for liquid nitrogen
7 Amplitude display
The lower part (2) is placed on the vibratory plate and the mortar with
ball (3) and grinding stock is placed into the plastic surround. Then the
upper part (1) is placed on the lower part, so that the seal ring in the
upper part is resting on the mortar edge and the bent ventilation tube
(5) is facing backwards and the amplitude display (7) is facing forwards.
The device is then clamped like a normal sieve set.
Liquid nitrogen is then poured in carefully through the funnel (6); it evap-
orates immediately and escapes through the bent ventilation tube. The
boiling nitrogen can be observed through the transparent Makrolon
screen. Nitrogen is added until the amount of vapour escaping
decreases. The grinding elements can then be cooled down enough for
grinding to begin. The same must be observed as for normal grinding
with the PULVERISETTE 0 as described above. (See Ä Chapter 6.1.2 ‘Fit‐
ting and clamping the mortar’ on page 22).
During grinding, refill the same amount of nitrogen that evaporates.
6.2 Setting the grinding duration
The grinding time can be set in increments of minutes using the +/- keys.
Values between 1 and 99 minutes are possible; after a grinding time of 1
hour, let the device cool down.
Continuous operation is set by holding down the "-" key until "P" or "00"
appears on the display.
Using the device
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