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Discussion Starter · #1 ·
While harvesting wet corn this year I had a problem with an excessive amount of fines in my sample. So I installed a screen under the clean grain auger instead of a solid trough. But I didn't know for sure what effect that might have on the amount if air blowing up through the shoe and chaffer. Sitting still with the Separator running I got out and it actually felt as if air were being drawn into the screen, like the velocity of the air coming off the fan was creating a venturi effect. Theoretically, this should actually increase the amount of air flow through the chaffer. However, once I got going with yet another rain delay my sample was free of the excessive fines, but I was getting a large number of small leaves and stalk pieces. I always run my fan to max rpm(1150rpm while harvesting).
So, my theory for the air flow dynamic is thus:
While running the machine empty a venturi effect(low pressure) does occur, but when you add grain and trash to the top of the shoe and chaffer the restriction in air flow creates positive air pressure in the chamber under the shoe where the clean grain falls. The positive air pressure looks for an escape and it goes out the screen under the clean grain auger. Its kind of difficult to test my theory unless someone wants to volunteer to hang underneath my machine while I drive.
Does anyone have any knowledge of this situation? Does anyone make a kit to speed up the fan? I'd like to have a way to remove fines so that I can push air through my bins, but I don't want to add leaves and sticks.
 

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location?? yields?? moisture??? rotor speed?? ground speed?? concave opening??? these are all things we need to hear so we can help you further but i cant really tell you much on what you have given us i mean no disrespect but this info will increase chances of diagnosis of your problem
 

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Discussion Starter · #3 ·
Wow?!? No disrespect but you missed the entire point of my posting. Which was the effect of the screen under the clean grain auger, and if the air would be released out, or if it were being sucked into the combine through it during harvesting. Since you obviously don't understand or haven't contemplated the situation why were you compelled to respond. Location? is this dynamic it going to be different in Iowa compared to Ohio? This is not a post about combine settings for a clean sample. If I wanted useless combine setting numbers I'd open up my operators manual and just run them.
 
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