THE COMMINUTION of difficult samples, like temperature-sensitive powder coatings and plastics, or materials with intrinsic moisture such as tea or herb leaves, can present a problem for some sample preparation mills. Fritsch says that its Pulverisette 14 variable high speed rotor mill has no such difficulties.
The way in which air is routed inside the mill, and the air vortex within the Fritsch Cyclone, cools the sample during grinding. This reduces thermal load, minimising clogging of the sieve rings and increasing throughput. The air flow arrangement also reduces cleaning requirements.
The ground sample is deposited by the air flow onto the sample glass – a convenient arrangement because the material is drawn directly into the glass for transport or storage. Fine dust is retained in the cyclone by the Hepa dust filter.
The result is particularly fast and effective grinding with minimum thermal load, says Fritsch, making the mill particularly suited to heat-sensitive materials and for the pre-crushing and fine grinding of samples with residual moisture. Extremely difficult sample materials such as synthetic resins, styrene, polyester, or other plastics can be embrittled by adding liquid nitrogen before being given the Pulverisette treatment.