Combines 1688 chaff

[greg]

Have you tried an Air Foil ChafferIJ

 

[John_W]

I think a little more info would help. What kind of a rotor, concaves and grates do you haveIJ How worn are the threshing partsIJ How fast are you running the rotorIJ How is the chaffer, sieve and fan setIJ Crop condition, wet or dry, yield and ease of threshing ect. Have you done quick stop or "kill stall" to try to figure out what is happening inside the combineIJ

 

[tj]

Questions: Which concaves are you using --wide or narrow spacedIJ Rear grates -- perforated or keystockIJ What is the length of the chaffer fingers -- long or shortIJ Does your chaffer have 2 stage adjustment or 3 stage adjustmentIJ Several years ago, a Canadian co. was installing what they called a throat tin which mounted above the fan opening. As air is blown underneath this device, a low pressure area is created on top, which will suck chaff thru the front of the chaffer. If one of these is installed, suggest it be removed -- you'll also get better air to the front of the chaffer. Also when this throat tin was installed, they shortened the front of the sieve by about 8" or so. This allows trash to fall in front of the sieve, directly into the clean grain. Did you post a few weeks ago about this problem, and did you say that it's worse on a windy dayIJ

 

[john]

We have a std rotor narrow concaves run the rotor 850rpm fan 1130rpm sieves upper 1_2" lower 3_16" return 5_8" does it in durum and ac barrie wheat new rotor bars

 

[tj]

First thing is to find out where the chaff is coming from. Suggest blocking the front of the chaffer. Use a piece of cardboard about 10" to 12" in width, long enough to double over for some strength, and wire it on to the top side of the chaffer at the very front. Explanation -- as trash falls on to the chaffer, more trash follows adding weight, and chaff is likely being forced thru in front of the sieve and into the clean grain by weight and shoe shake. The chaffer is likely already partially blocked by this trash, prbably by uneven air blast across the front of the chaffer which precludes ability to lift chaff up and to the rear. If this relieves most of the problem, I'd leave the cardboard in place. If cleaning on the chaffer is improved, you will actually increase your capacity since you'll probably be able to run the chaffer and sieve with wider openings, and the air will be better distributed. Reason for cardboard is that it's flexible and still allows adjustment. If this doesn't help, the chaff has to be coming from elsewhere. I'd recommend an airfoil chaffer, as well. One of these will provide more lift by directing the air straight up. Also, occasionally, dealers will install metal plates over the fingers which project off the rear of the grain pan -- these will move trash back further, but the same problem remains. If you have these installed remove them. The cardboard is much more effective. Hope this is clearer than mud.

 

[M__Gorden]

Here are some photos of chaff free samples possible with axial-flow combines.