In this article, cereal feed for horses is screened and analyzed. The content of crude fibers is especially critical and subject to errors. This analysis is performed using an ultra-modern instrument made by Gerhardt.
Modern analyzers are characterized by the reduced use of chemicals and optimized timing. Approximately 1 g of the weighted sample to be analyzed is added to the analytical instrument. The batch size is large, which means that a mixed sample of at least 1 kg cereal has to be comminuted.
In the individual components seen in the picture below, the sorted pellets weigh 0.7 g, the yellow chunk material 0.3 g, and the husk almost nothing. Crude fibers are concentrated especially in the husks.
As a result, insufficient comminution will lead to faulty analyses. The errors cannot be attributed to the analysis instrument, but instead to the inhomogeneous sample. The net weight increase is in opposition to the use of chemicals of acid and bleach and the required times for the cooking process.
The production of a homogenous sample with the help of the suitable laboratory mill is important. For the one-step-comminution with only one instrument, a number of tests were conducted using the Variable Speed Rotor Mill PULVERISETTE 14 classic line.
The finest sieve measuring 0.5 mm was utilized, but the obtained fineness was not adequate. Clearly elongated husk remains could be detected. The solution is therefore a two-step comminution.
For pre-comminution of larger quantities of cereal, the use of a cutting mill is recommended. The Universal Cutting Mill PULVERISETTE 19 is further recommended due to its good cleaning performance in the contamination-free preparation process.
For the next step, the Variable Speed Rotor Mill PULVERISETTE 14 classic line is chosen for the fine comminution of a smaller mixed sample.
Larger sample amounts can be pre-comminuted in batches with a 2 mm sieve and a PULVERISETTE 14 classic line. This system caters effectively for a limited budget, requiring investment in only a single mill.
In this instance, a subset amount was finely comminuted using the PULVERISETTE 14 classic line, however, this time using a sieve with a 0.2 mm mesh width.
The sample is put through the 2 mm sieve through the opened collecting pan of the mill. It can be clearly seen that the result is still inhomogeneous. For the formation of a smaller mixed sample, in the second step of the comminution, sufficient mixing and exact sample division have to be performed. For this division the Rotary Cone Sample Divider LABORETTE 27 is recommended.
The sample put through the 0.2 mm sieve is illustrated in the picture below. After mixing the prepared sample of 1 g, a crude fiber analysis, can be obtained.
If the Universal Cutting Mill PULVERISETTE 19 is available, or larger numbers of samples need to be continuously processed, it is recommended that the larger amount of the sample be pre-comminuted with the cutting mill.
After sample division is performed, the smaller quantity obtained is finely comminuted with the Variable Speed Rotor Mill PULVERISETTE 14 classic line.
This information has been sourced, reviewed and adapted from materials provided by FRITSCH GMBH - Milling and Sizing.
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