Combines Straws in sample from airjet chaffer

[theredgreenshow]

Sounds like you may need to put the wires in the concaves to prevent straw from going to the chaffer. Which grates are you usingIJ Installing the bars on slotted grates would help too.

 

[Jimmy_Clark]

Concaves aren't bored for wires. We have a problem in that wheat straw tends to "wrap" on wires, blocking concaves, which is why we find the helical concaves such a boon. We have keystock grates, which are standard European small grain option. Apart from straws, sample is good: no white caps or unthreshed heads (cracked grains not a problem at our moistures -20%!)Returns monitor hasnt registered 1 bar on display all day. Spot rate 35-40 metric tonnes_hr, that is, 20ft head, 3.25mph in 4.5tonne_acre crop. Sorry I havent energy to get my head round this bushel thing! At least Ive converted speeds, distances and areas from metric!

 

[theredgreenshow]

Sounds like you work in pretty tough conditions there with 20% moisture. I talked to a neighbor who runs 2 slotted grates and 1 keystock grate to cut rotor loss when he needs to, otherwise, most of us around here run slotted grates in wheat. I wonder if this would help keep some straw from going to the chaffer, or maybe even add a second cover plate. Where are you at anywayIJ Do you end up drying your wheat at that moistureIJ

 

[shellman]

Have you tried changing the vane position and speeding up the crop down the rotorIJ Other quesion is the straw coming from the rotor, or is the fan sucking straw inIJ What direction is the prevailing wind and how strngIJ I know the last couple years here in central Kansas when you get a 40 mph constant wind from the south_southwest everything is great headed south, but not true north or east bound. The wind gets in under the straw hood and seems to just block the residue from being discharged. Just a couple of quick thoughts.

 

[Jimmy_Clark]

Thanks for your replies. I am in Scotland UK. We have been stopped by rain, but will take the time to turn off the chopper and lay out some swaths when we start again. That way I can get my concave as open as possible consistent with completely threshing wheat. Do you think I should speed up the rotor to get the straw through quicker or slow it down to reduce break upIJ

 

[theredgreenshow]

I think that I would slow it down. I have seen where slowing it has, in some cases, improved the threshing because you are increasing the pressure of the wheat upon itself as long as you maintain ground speed. I have seen this in small seed crops such as carrots and radishes. I also like the idea that shellman has about speeding up the vanes. As long as you are completely threshing the wheat, I see no reason to keep it in the rotor any longer than it has to be.

 

[shellman]

Remember that in the axial flow we depend upon crop on crop to thresh the grain and centrifugal force to separate. I agree that slowing down the rotor will most likely help if we are indeed overthrashing. One of the hardest lessons to learn or remember with these machines is that you have got to keep the rotor full to work correctly.

 

[PETERBIll]

The secret to an airjet chaffer is that they won't work right unless you run at least 1200rpm on your fan for wheat, corn, beans. You'll get crap in your grain sample if you don't run it full bore on the fan.