Straw, hay, dried plants; herbal teas are mostly very bulky samples. An average shopping bag contains 300 g straw or expressed like this: 100 g of uncomminuted straw take up the space of 1 to 2 litres. These materials are very voluminous. For the comminution only a cutting mill with a high rotor speed can be considered. So the choice is between the Cutting mill PULVERISETTE 15 and the Universal Cutting Mill PULVERISETTE 19.
Are the recommendations in regards to cleaning and expenditure of time higher though, the Universal Cutting Mill PULVERISETTE 19 is implicitly to be recommended.
Larger sample amounts or also a larger number of samples demand a fast throughput of the sample. The limiting element with cutting mills is the addition of bulky samples. Here the recommendation can only be to combine the Universal-Cutting Mill PULVERISETTE 19 with the Cyclone separator. The Cyclone separator generates an air current, which downright draws the bulky goods into the funnel (on the right side of the photo), draws it through the mill, thereby at the same time acts as a cooling current and finally separates the comminuted material into the sample bottle (pictured on the left side of the photo, connected to the black funnel). Everyone that is faced with this task and is familiar with the troubles of the comminution of straw is totally enthused after having once worked with this system.
Straw was comminuted with a Universal Cutting Mill PULVERISETTE 19, equipped with a 0.5 mm sieve cassette. During the first test, the sample was processed without the Cyclone separator, for the second test the Cyclone separator was used. When comparing both finenesses, the sample processed with the cyclone separator contains slightly longer shares. In the air current generated by the Cyclone separator, longer parts are rather aligned and pushed through the sieve.
With the Cyclone separator and a 0.25 mm sieve cassette, 1 kg dry straw was put through in 10 minutes. In order to understand this amount better, refer back to the volume of 1 kg uncomminuted.