Wood

If such a samples should be ground on a regular basis, we recommend choosing the Rotor with V-cutting edges and fixe knives made of hardmetal tungsten carbide for a much longer durability.

Sample has been fed completely. Grinding sound almost vanished after about 1 minute and 305 grams of output.

We interrupted the grinding process, because the largest fed piece of ~ 14 cm used to jam the protected hopper (see additional photo page). This piece got removed and has been fed a second time to the hopper, so this piece got fed in a different direction again and got ground properly. Pre cutting (e.g. with a band saw) of pieces > 10 cm might be recommended be on the save side, so all pieces will get grabbed properly.

After a total grinding time of 110 seconds, all pieces have been ground successfully. Cleaning can be performed afterwards, rapidly by vacuuming with a soft brush.

See result 2 for the grinding trial with 1,0 mm sieve cassette. With sieve cassette < 2 mm, some sample will be problematic. We are guessing that this kind of sample (dry wood chips) should be ground without significant problems, but a higher residue left loose on top of the grinding chamber.

The second sample (200 grams of wood) was ground with the 1,0 mm sieve cassette. After two minutes of grinding, an output of 111 grams has been found in the collecting vessel. After 3 minutes, output rose to 148 grams. After a total of 5 minutes, an output of 171 grams has been found in the collecting vessel.

We interrupted the grinding process after a total of 7 minutes, because no significant further output has been achieved.

A higher amount of sample use to lye loose on top of the 1,0 mm sieve cassette. < 20 % of trapezoidal openings might be blocked lightly with fragments of sample. For cleaning, we recommend using a wired brush.

For sure, desired amount of samples (500 grams) can be ground in one batch; for an output of 500 grams, we recommend to feed about 530-550 grams. We are guessing that about 8-10 minutes might be required to achieve that task.

With the protected funnel with sample pusher, also wooden pieces up to 7x8 cm long pieces can be fed to a Universal Cutting Mill PULVERISETTE 19. This machine has big advantages in case of of a usage of sieve cassettes with < 2 mm perforations.

We fed the funnel to the maximum and had to use the sample pusher to support feeding on a regular basis. After 2:15 minutes, it has shown that some pieces might lye in front of the rotor knives without getting grabbed properly.

We aborted the trial after 3 ½ minutes to remove those jamming pieces (see photo page) and readopt the feeding of particles with lower feed rate (about 30-50 g per batch). This way, no particles jammed the hopper.

All sample has been fed and ground after a total of 5 minutes.

Grinding chamber is almost clean, even higher amounts can be ground this way.

With the last trial, we ground 500 grams of wood with the desired 1,0 mm sieve cassette. This time, we started to feed lower amounts of sample (~ 30-50 g) to the hopper and guided the sample directly into the grinding chamber before the next hand full of wood chips got fed.

This way, no sample blocked inside the hopper and all sample has been ground properly. It took about 5:20 minutes until the last pieces of sample have been fed and grinding sound vanished.

After grinding, only a very small amount of sample uses to be left loose inside the grinding chamber.

Cleaning can be performed rapidly by vacuuming with a soft brush.

We don’t expect problems do divide samples which was ground to < 1 mm by Rotary Cone Sample Divider LABORETTE 27.

As desired, one of the ground samples (< 4 mm particles from result 3) has been used to divide with our Vibratory Feeder LABORETTE 24 and Rotary Cone Sample Divider LABORETTE 27. For such large amounts of sample, we recommend using the 1:8 head because only with this head, 500 ml bottles can be mounted to collect such high amounts of sample (62,5 grams per glass).

The funnel of the Vibratory Feeder LABORETTE 24 needs to be refilled about 3 times to divide the complete sample of 500 grams.

With 4 mm sieve cassette ground particles, it might be possible that sample will jam inside the opening of the hopper and feeding might be supported with a small brush eventually. In our trial, we lifted the hopper to its maximum - it wasn’t necessary to support the feeding of particles.

We used a feed rate of ~ 20 grams / min and achieved with an exactness of ± 0,7 grams per glass by eccentrically feeding. Two of the 500 ml glasses have been packed separately for demonstration, the rest of sample was packed together. A dividing of ground samples < 1 mm shouldn’t be problematic. Like grinding results, still a bit of fine wooden dust uses to stick lightly to the Vibratory Feeder LABORETTE 24 and Rotary Cone Sample Divider LABORETTE 27. It is possible to brush off such particles and feed to the collecting glasses as well.

Rest of sample was fed a second time with the U-shaped feeder channel; the funnel does not need to be lifted that high; we recommend feeding with a U-shaped channel instead of the standard V-shaped feeder channel.