Retsch PM 200 - Manual (Page 26)

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Retsch GmbH
26
Use of the closing device for milling cups
 After filling the milling cups these must be closed with
closing devices available as accessories.
 For milling cups with material inserts, ceramics or
tungsten carbide use only closing devices which support
the material insert of the milling cup lid. This is
absolutely essential owing to the anticipated internal
pressure.
 Use of agate milling cups for wet milling with solvents
should be particularly carefully considered owing to the
internal pressures produced and the non-homogeneous
material properties of this natural product.
 Tighten the clamping screws of the closing device with
a torque of 2.5 Nm. Internal pressures of up to max. 5
bar are permissible only with this preliminary tension.
 NOTE
Damage to the grinding chamber cover and to the
device
The three screws on the safety clamp on the aeration
cover can become loose and damage the inside of the
device.
After tightening the clamping mechanism, check if the
three screws on the safety clamp are still tight.
 Please note that the milling cups can easily be heated
to above 100°C, depending on the milling cup size, ball
filling, speed and milling time.
 The PM400 is fitted with a ventilator which sucks the
waste heat produced during milling directly out of the
milling chamber.The suction volume per hour is greater
than 20 times the milling chamber volume. The
ventilator has a standstill monitor with signalling.
 If necessary the air stream of the ventilator should be
carried off into a duct during milling.
 Check firm fitting of the closing device before removing
the milling cups.
 Remove the milling cups only with closing device and
open only in a safe position (extraction unit) after
cooling.
For wet milling in milling cups with material inserts do
not use old closing devices which clamp only the
gripping edges of the milling cups. The material inserts
can be pressed out by possible internal pressure.