Combines Adjustable Precleaner benefitsIJ

[Cornsheller]

The grain that passes through the pre-sieve goes directly to the lower sieve but that material that doesn't pass through goes to the top sieve. You can visit the Deere website and go to the Dyna Flow Cleaning System for verification. The larger material that the fixed setting lets through will either get into the grain tank or be returned for processing. In the return trip it will likely get through the pre-sieve again etc. etc. etc.

 

[Burke]

I have a 9860, the grain that goes through the pre-sieve goes to a shaker pan that dumps onto the top seive(chaffer).

 

[Cornsheller]

Here is the language I copied and then pasted from the 9860 cleaning system information on the Deere website: (begin website language paste)) The raised-center fixed front chaffer is standard on all 60 Series STS combines. Material drops down the incline of the louvers, helping to thin the mat. This results in more aggressive separation of material at the step pan. Air from the cleaning fan seeks the higher elevation of the raised front chaffer, and increased performance in cleaning is achieved. Up to 40 percent of the threshed grain before it reaches the primary cleaning shoe. Grain moves directly to the cleaning sieve, reducing loads on the main chaffer. (end of website language paste) I thought all brands had a pre-sieve that sent the material which had gone through the pre-sieve directly to the cleaning sieve as the Deere language indicates for the 9860.

 

[Farmerman]

I don't know as much about the 60 series, but getting an adjustable precleaner on the 50 series definitely helped. The non-adjustable precleaner was way too far open for the air blast to get and keep the chaff airborne. (We don't combine corn--maybe this doesn't pose a problem). Therefore the front of the chaffer was loaded with a thick mat of grain and chaff which didn't start separating until farther back. If not properly suspended or airborne, a lot of sluffing material will fall through onto the sieve. It is the overloaded sieve which causes all the problems i.e. higher returns, poor tank sample, or reduced capacity when slowing down to prevent these problems. Closing down the precleaner gets a harder air blast which gets the material suspended and allows the chaffer and sieve to work properly.

 

[HRGD]

The need for the addition of the adjustable pre-cleaner is the result of the STS's inability to thresh wheat at the concave area. If the grain was threshed from the heads there would be no need for additional attachments like pre-cleaners and concave cover plates. The largest problem with the machine being unable to properly thresh grain is the concave itself. The wires are TOO HIGH. There is no way the volume of material going across these concaves can be properly separated, the result being unthreshed heads on the pre-cleaner, chaffer and clean grain sieve. The addition of the adjustable pre- cleaner and concave cover plates are attempts to fix the result, not the root cause.

 

[Burke]

Cornsheller, I read that on the JD website also.I looked again at my 9860 and I can't see how the grain from the precleaner cango to the cleaning sieve. There is a corrugated shaker pan under the precleaner that extends to the chaffer, with plastic fingers that extend out over the chaffer.I think HRGD is right about the rotor not doing an adequate job of threshing in the first place. The cover plates are a bandaid on an axe wound. Reducing capacity.

 

[Cornsheller]

I don't have a 9860 to look at and I'd believe your eyes over company advertising. I know that Deere had an experimental concave on test as it was installed on a friend's 9750. They gave up though on that particular idea because when they reduced the material getting to the cleaning system the rotor loss, and grain quality, went the wrong way in a hurry.

 

[Farmerman]

You're probably not too far off the mark, HRGD. The STS does have a relatively small cleaning system compared to capacity. Any improvements in this area can only be helpful. A lot of the returns are chaff and should not be there if the cleaning system is operating properly. An adjustable precleaner certainly helps to alleviate this.

 

[Bart]

I'm trying to understand what you have in your machineIJ In my 9650 I have the plastic fingers that extend out over the chaffer,they are attached to the back of precleaner.From what you said above you must have two rows of fingers one above the other.

 

[HRGD]

To try and increase the thresh I installed nine of Deere's new threshing elements on the rotor, may as well have saved the time and the money. Did not make one bit of difference to the sample. If we cannot get the grain out of the head on the first pass then the next best thing would be a chaffer with separately adjustable areas like we used to have. Think about it, if we could have the main area of the chaffer closed down to run the unthreshed material back to the area above the return auger which would be open more than the main area. Now we have the unthreshed material going directly into the return rather than along the bottom sieve to get into the return, now we can open the sieve! I realize this would necessitate the changing of how the sieves are adjusted.