DAS 96-20 Evaluating forages and TMRs using the Penn State Particle Size Separator
4
PARTICLE SIZE SEPARATOR INSTRUCTIONS
(
CONTINUED
)
___________________________________________________________________________________________________________________________________
Using Weibull paper
Weibull paper is used to graph the
distribution of forage and TMR particles of
the sample using the three weighed fractions
from the sieves. The number of forage and
TMR particles in a sample do not follow a
normal distribution population, however
they can be plotted as a straight-line
distribution using the unique Weibull
graphing paper.
Plotting the sample allows one to
extrapolate beyond the measured points (.75
and .31 inches). It should be noted that the
accuracy of these values decrease as the line
is extended beyond these two points.
Therefore the line should not be drawn
beyond .2 and 1.5 inches.
Referring to Table 2, value [e] refers to
0.75 inches and value [f] to 0.31 inches.
These percentages are plotted on Weibull
paper and an appropriate line drawn
between the two points (Figure 2).
On Weibull paper, the horizontal axis is
for particle size and the vertical axis is for
cumulative percent undersized. The axes
are not linear. For the example given in
Table 2, the following deductions or
statements can be made:
- approximately 8% of the feed is > 0.75
inches
- approximately 30% of the feed falls
between 0.31 and 0.75 inches
- approximately 62% of the feed are <
0.31 inches
Another interpretation could be:
- approximately 97% of the feed are < 1.0
inch
- approximately 80% of the feed are
<0.50
inches
- approximately 48% of the feed are < 0.22
inches
This example would indicate a typical, well
cut corn silage. This material can be used as a
component of a forage-feeding program where
another longer forage material is also used.
Figure 1. Shaking pattern for particle size separation.
5
5
5
5
1.
2.
3.
4.
5
5
5
5
5.
6.
8.
7.
