Saskatchewan | masseypride - 9/26/2008 15:02
You can blow anything out the back a machine with too much air. Unthrashed heads need to be addressed with the rotor not the sieve or fan. Slow the fan down, your blowing all the grain to the back of the sieve and into the return.
First, thanks for responding. I don't think the fan can be slowed down because the air-foil chaffer seems to stop separating the chaff and it ends up on the bottom sieve. The air-foil chaffer has larger holes and blows the air more vertically than a standard, adjustable chaffer. My theory is that the air-foil chaffer does not work well in this combine. I know that with a MF 860, there was a baffle behind the fan that could be adjusted to direct more air upwards and you were recommended to do so when installing an air-foil chaffer.
Recheck the return. If its still heavy, open the sieve up even more until the returns are what you would like to see. What rotor speed, concave opening, and concave configuration? Why do you feel the need to run the fan so high? Is it because your overloading the chaffer? If it is, you are over-threshing the grain with the rotor.
I think the rotor was running at about 800 rpm and the concave clearance was 0.10-0.15" (any larger clearance seemed to reduce capacity and result in more unthreshed heads). We had both blanks installed over the front part of concave.
Creating too much material other than grain (MOG) inside the machine. This material makes it diffucult to seperate out the grain effectively with minumal losses. Remember, you only want to remove the grain from the heads, not remove the whole heads. I would guess your running too much rotor speed and over-threshing the wheat.
I think there was a lot of broken off heads in the cleaning system. Would slowing down the rotor and increasing the concave clearance help?
Do a full load shut-down and look at the grain pan and chaffer. On the grain pan, you only want grain evenly across the pan with only small amount of chaff, no straw. Anymore than that your overthreshing the wheat. The Chaffer should look similar.
That sounds like it could be an informative exercise. It will have to wait until next year, unfortunately, since we are all done our wheat.
Thanks again for your suggestions. |
MF 9895 clean grain in return
