Hippophae rhamnoides - dry parts and seeds of plant

With the used sieve cassette of 0,5 mm, the complete sample amount got ground in one minute. Only minimal residue of sample use to remain mainly loose inside the grinding chamber and can be removed by vacuuming with a brush.

A grinding of up to 500 g of sample is plausible in one batch. We would recommend using a collecting vessel of 10 L volume for this sample.

Probably also a 0,25 mm sieve cassette can be used for a grinding of such a sample too (see result 2).

By using a sieve cassette with 0,25 mm trapezoidal perforation, the output of ground sample use to get lower every minute.

After 1 minute of grinding, already 22 g of ground sample got found in the collecting vessel. After 2 minutes, output rose to 38 g. After a total of 3 minutes of grinding a output of 51 grams has been found. Afterwards, no significant further output has been achieved.

We interrupted the grinding process and checked the grinding chamber. Probably fat content of the seeds, which use to be found in the sample as well started to stick and blocked the knives and openings of the sieve cassette.

For cleaning, we ground wooden chips with the machine to detach sticky sample particles from the grinding chamber. The sieve cassette has been cleaned with hot water.

Also a rotor speed mill can be used for a grinding of such a sample. In our first trial, we used a 0,5 mm sieve ring for grinding.

With standard pan, up to 50 g of sample can be ground. For your application, we recommend using the optional accessories for grinding large quantities.

We used ~ 175 g of sample and ground the sample within 90 seconds. After grinding, ribs of the impact rotor and openings of the sieve ring remain free. A grinding of higher amounts (up to 500 g) should be possible without problems.

Sample which will be ground with a rotor speed mill usually uses to be much finer as the openings of the sieve ring allow to pass. Generally, a d50 < half of the openings of the sieve ring will be found after grinding. For a 0,5 mm sieve ring, we expect that 50 % of ground particles will be < 250-350 µm.

Possibly also a 0,25 mm sieve ring might be capable to grind the sample even finer (see result 4).

In our last trial, we used a 0,25 mm sieve ring instead of a sieve ring with 0,5 mm trapezoidal perforation.

For been save, we reduced feeding speed to hinder a blockage of sample in front of the sieve ring. It took about 350 seconds until all sample has been fed.

After grinding, it has shown that fine ground sample material uses to stick to the collecting pan and to the outside of the sieve ring. Almost ½ of the openings of the sieve ring are already blocked with small sample particles.

For this, we don’t expect that higher amounts of sample can be ground this way. If this result will be desired, we recommend a batch wise grinding of sample and clean the sieve ring after each every ~ 150 g of sample.

We don’t expect that a previous chilling in liquid nitrogen, or the usage of the optional sample exhauster system with cyclone separator will improve a grinding with 0,25 mm sieve ring significantly.