IKA M 20 Universal mill - Manual (Page 7)

7
M20 0705
Plastic, soft or smeary materials have to be cooled if they are to
be ground.
There are two hose couplings located at the rear of the grinder in
order to connect the cooling brine. Cooling with tap water is usual-
ly sufficient for substances which become hot as a result of the
grinding operation and are thus given to smearing or those that
produce oil.
The grinding chamber may only be filled halfway especially when
drugs containing oils and similar materials are ground.
If more refrigeration is required then the ground matter should be
cooled prior to being put into the grinding chamber.
The followiung procedure shall apply if liquid nitrogen is used in
order to embrittle the material to be ground:
Safety information:
Suitable protective gloves must be worn when filling and
transferring liquid nitrogen!
Protective glasses must be worn!
• The sample to be ground is put into a suitable vessel (e.g. eva-
porating dish) and covered with enough liquidnitrogen until it is
completely covered.
When using liquid nitrogen make certain that the sample is not
capable of reacting with oxygen.
• Cool grinding chamber using liquid nitrogen.
• Put the deep-cooled sample into the grinder and grind approxi-
mately 15 seconds.
• Then open the grinder and add liquid nitrogen for only as long as
it takes for the sample to become deep-cooled again (embrittled).
Safety information:
Make certain that the liquid nitrogen has evaporated
before beginning the grinding operation.
NOTE: Danger of overpressure!
• Repeat the grinding operation for approximately 15 seconds.
• Repeat the sequence of cooling and grinding until desired finen-
The grinder is protected against overload by means of an overcur-
rent protective device. In the event of overload the overcurrent
protective device interrupts the current supply. Restarting is car-
ried out by pressing-in the black button at the rear of the grinder.
The motor is switched on via push-button at the front.
The devive consits of three basic units (drive unit, middle part and
cover) which are connected to each other by means of quick-relea-
se locks. When assembling the three units make certain that the
hose coupling for cooling the middle part is located at the rear of
the device. When putting on the cover make certain that the
safety pin in the middle part is pushed down by the pressure pin
on the cover. Otherwise, a tight and reliable connection is not
ensured and the grinder will not start.
The device is started by pressing the push-button at the front.
Fineness is mainly dependent on how long the grinding operation
is performed.
If materials are to be ground that are smaller than a certain grain
size then it should be sieved and the residue in the sieve is put
back into the grinder. For sharp-edged material wich is thus very
abrasive, it is recommended that the entire quantity is left in the
grinder in order to additionally exploit the properties of the materi-
al.
Motor Circuit Breaker
Description
Grinding
Grinding while cooling