|
Set the chaffer just wide enough to ensure that the grain falls through before passing the length of the chaffer. If the chaffer is opened too wide, it may overload the sieve with chaff and straw and increase the tailings. If the chaffer is not opened wide enough, excess grain will be moved to the tailings and some will be lost out of the rear of the combine.
Grain losses in the cleaning unit may be caused by:
1. Too little fan blast or too narrow chaffer openings, which results in a layer of straw or chaff on top of the grain.
2. Too much fan blast, which blows the grain out of the combine.
It is important to know which of these reasons is causing the cleaning shoe losses, as this will enable appropriate action to be taken.
|
Re 1.) The problem may be caused by overthreshing as well as too little air from the fan. Check the amount and condition of the straw.
If the straw appears to be excessively broken or chewed, the cylinder and concave must be adjusted to reduce overthreshing. If the straw is whole and unbroken, then more air is needed to suspend the straw and chaff so that the grain can drop through the sieve, or the chaffer needs to be opened slightly.
IMPORTANT:
Always check the result of one change at a time, before carrying out the next adjustment.
Re 2.) If too much fan blast is the problem, then there will be very little chaff and straw on the cleaning shoe. Reduce fan speed and check the results.
|