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Holy Cow, now that's good marketing palaver...an over-shot impeller to assure better straw quality. What they aren't admitting is that a more natural flowing under-shot impeller after a tangential tine separator drum is patented and in use by a competitive combine mfg., just like the CTS, where an over-shot impeller is required due to an under-shot design leading into twin separation rotors is patented and in use by a competitor too. But I like their concept, it's proven well by the competition.

You gotta love physics, it makes the combines go 'round and 'round, not to mention the World. Relative to tangential threshing, under-shot is the path of least resistance and the path of "least resistance" means less stress on the crop and potentially MOG and greater feeding efficiency.
 

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Muddy, you're over my head here. Can you enlighten me on this under/over shot impeller situation? Is this the intake of the rotor?

-Lance
 

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I like the farmers weekly and the profi magazine. Is there anything like this in the U.S. that goes into such detail in every issue and article like these European magazines do????????????????
 

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Quote:Muddy, you're over my head here. Can you enlighten me on this under/over shot impeller situation? Is this the intake of the rotor?

-Lance


Under-shot impeller = material exiting the threshing cylinder and goes under the rear impeller and then into the separator (i.e., Deere 9000 series straw walker combines and Lexion rotor combines).

Over-shot impeller = material exiting the threshing cylinder goes over the rear impeller and into the twin separation rotors (i.e., Deere CTS combines)
 

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Discussion Starter #8
Just for comparison purposes here are some pics of the threshers from the manufacturers websites.

John Deere's new T-Series and WTS




Claas walker system




John Deere and Claas hybrid conventional/rotory threshing systems


 

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I still believe the Claas has the better system by far. Those rotors will not only run faster and push the waste straw from the separator at a much faster rate than walkers, but as with anything making contact with crop material, there's still some thresh as well. This is what really completes the cycle.

Honestly, I believe it would be really great to achieve so fine and thorough a thresh at the cylinder/drums concaves, that there would be no real need for a returns system in the first place, but leave it there. After all, we want it ALL!
 

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Good job Laury, thank you.

Linda, the combine has to do all the threshing in the cylinder area, otherwise it has failed at its job. That's why the latter part is called separating. NH really takes this serious and does not even return the tailings to the concave, because it did not get done right there the first time.
The faster the separating rotors run, the higher the risk of getting into the rifle effect, especially in larger grains like corn and beans. This is one thing NH is fighting on the twin rotors. Because the CR has two rotors they have to be smaller to fit in the combine. Therefore they have to run faster to get the same work done leading to a much higher risk of rotor loss.
 
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