Dried Carrot Residues

With our first results, we used the Knife Mill PULVERISETTE 11 for comminution. The sample is brittle enough to be ground to a fine powder. Even without the presence of static knives (for shearing forces).

The grinding vessel made of polycarbonate was equipped with our standard knife and the standard silicon lid. The mill was adjusted to 10.000 rpm (max. speed without turbo mode).

We added 50 grams of sample into the grinding vessel. Surely also 100 grams of sample would fit into the vessel as well.

We ground the sample in manual intervals. After only two seconds of grinding, the majority of sample was ground fine. Only a few pieces up to 3 mm were still present (see picture 2). We proceeded grinding for a total of 10 seconds and checked the fineness again.

Plenty of sample was ground powder fine (see picture 3). Surely a few fragments might be present with ~ 1 mm length. We don’t expect that longer grinding times will improve the result significantly.

To achieve a better fineness, we recommend using a Variable Speed Rotor Mill PULVERISETTE 14 classic line (see result 2).

For an intensive cleaning, the grinding vessel was filled with soapy water and ground for five seconds. Afterwards, the equipment was flushed with fresh water and dried off.

With our second trial, we wanted to demonstrate grinding with our Variable Speed Rotor Mill PULVERISETTE 14 classic line. The mill was equipped with a sieve ring with 0,35 mm trapezoidal perforations. Also, an impact rotor with 12 ribs was used. The sample was very brittle; eventually a feeding of the sample could be performed without a manual pre-crushing.

To be on the safe side, we put 50 grams of sample into a plastic bag and pre-crushed the sample rapidly to < 15 mm start size (< 1 min was required). Now the sample was slowly transferred into the grinding chamber. It took 90 seconds until the complete sample was fed and ground. The grinding sound vanished rapidly after the last fragment was fed. Only a bit of fine sample dust escaped the feeding funnel during the grinding process.

The used sieve ring was not significantly clogged with sample material. For a grinding of a 100 grams in one batch, we would recommend using the optional accessories for grinding large quantities (a paper filter bag system); or the Small Volume Cyclone (passively or actively used with a vacuum cleaner connected – depending on the dust exploration by the plastic air filter frit for passive use).

When a air stream is provided through the grinding chamber, also no significant dust of sample will escape the feeding funnel anymore.

For intensive cleaning, all grinding parts were disassembled and washed off with warm water.