Retsch PM400 - Closing the grinding jar

Operating the machine
37
Stainless steel
Up to 200°C
Tungsten carbide (TC)
Up to 150°C
Sintered corundum
Up to 120°C
Agate
Up to 120°C
Zirconium oxide
Up to 120°C
Silicon nitride
Up to 120°C
5.19 Closing the grinding jar
After filling the grinding jars, they should be closed using the locking mechanisms
available as an accessory.
Fig.
27
: Locking mechanism
In the case of grinding jars with material inserts made of ceramics or TC, only use
locking mechanisms that support the material insert in the grinding jar lid. This is
essential due to the expected internal pressure.
NOTICE
During wet grinding in grinding jars with material inserts, do not use the older
locking mechanisms. Older locking mechanisms only clamp the gripping flanges of
the grinding jars, which means that the material inserts may be pushed out if
internal pressure arises.
Use of agate grinding jars for wet grinding with solvents should in particular be
reconsidered because of the internal pressure that arises and the inhomogeneous
material properties of a natural product.
Tighten the clamping screws on the locking mechanism to 2.5 Nm. Only with this
initial tension are internal pressures of up to 5 bar permissible.
NOTICE
Damage to the grinding jar lid and the device
The three screws on the safety clip of the aeration cover may become loose and
damage the inside of the device.
After tightening the safety clamping device, check that the three screws on the
safety clip are still screwed tight.
Please note that the grinding jars may heat up to over 100°C depending on the
grinding jar size, the ball filling, the speed and the grinding time.