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Double
Double Overlap
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All
KRM fertiliser spreaders use a double double overlap spread system,
this system offers the largest amount of overlap and therefore the
highest degree of tolerance when spreading.
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The
diagrams below demonstrate that the left hand disc applies fertiliser
across the full spread width as does the right hand disc, therefore
a true double overlap tramline to tramline across the full width
has taken place.
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| As the machine spreads the next tramline another double overlap is applied. It can now be seen that the area between the tramlines which has now had its whole application has received 4 applications two from each disc. In this way the spread pattern is built up little and often. When spreading in the real world there are many factors that can affect the evenness of spread, such as wind, uneven ground, material variations and PTO speed fluctuations. By using the Double Double overlap system where effectively 4 applications are being applied any external factors will have a much smaller affect than they will with other spread systems offering less overlap. |
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| Tray tests are regularly carried out by Bogballe the manufacturers who have their own test hall. This is done to ensure the accuracy of their machines and also that the spread charts supplied with machines are up to date and include all fertilser types. The diagram below shows actual test hall data for a machine doing a tray test with only the left hand disc spinning. As you can see an even triangular spread pattern is achieved and fertiliser is spread across the full 24m spread width | ||
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The
next diagram in the sequence is showing just the right disc spreading
and again we have a very even triangular shaped spread pattern across
the full 24m spread width.
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This
last diagram in the sequence shows the result when both disc's are
running together. The red line along the top indicates the overall
spreading result when the machine spread the adjacent two tramlines.
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| The diagram below shows what would happen if the spread pattern was overlapped at different spread widths. It can be seen that at 24m which is our target spread width the coefficient of variation (or evenness of spread) is 4.5% an excellent result. What this diagram also shows is that the accuracy of the machine is not lost if for some reason it is not driven at 24m for example on grass. Where the actual spread width may vary due to driving accuracy. It can be seen that the coefficient of variation remains below 6% at all widths below 24m and only exceeds 10% at 28m. (Stripes start to become visible in a crop at 20%, KRM do not publish spread charts for machines which give a coefficient of variation worse than 10%). This highlights the tolerance the KRM machine, all external factors such as PTO speed, sloping ground, material size and wind, have the same effect in the field as driving at an incorrect width. | ||
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| This is why KRM fertiliser spreaders always do extremely well in any independent testing, the machines spread pattern with maximum overlap and gentle triangular shape ensures accuracy of spread with minimum settings. | ||
