Little combine pumps out large numbers

ST. PAUL, Minn. – The Gleaner Super 7 has the biggest airflow in the combine world at 19,706 cubic feet per minute.

It also has the biggest tank option at 390 bushels and one of the fastest unload rates at four bu. per second.

All this capacity is tucked into the smallest and lightest Class VII chassis in the industry. The S7 weighs a little less than 30,000 pounds and sports the same external dimensions as the R6.

Farmers are probably taking compaction more seriously, but they have always known the potentially high cost of sinking a heavy combine into the mud.

Farmers will get to see the new S7 for the first time at Big Iron in Fargo, North Dakota, Sept. 14. It will also be at Agri-Trade in Red Deer Nov. 10.

“Producers want more performance, but they do not want bigger, heavier combines,” said Gleaner product manager Kevin Bien.

Electing to stay with a lightweight chassis and the 31-year old transverse rotor arrangement, Gleaner engineers decided they could pump more performance into the compact R6 package.

“Super size really describes what we’ve done to the R6 to create the Super 6 and Super 7,” Bien said.

“We have a larger processor, new concave, new constant pitch helical, larger accelerator rolls, more distribution augers, better cleaning, new residue management with choppers and spreaders to match our 40 foot headers. And we’ve removed that slope sensitivity issue for good.

“Since 2007, we’ve introduced over two dozen other functional upgrades in preparation for this new processor we had planned to introduce for 2011.”

The biggest upgrade is the 30 inch diameter rotor with a 360 degree perforated wrap in the S6 and S7.

“We did not want to build a bigger combine to get better performance,” Bien said.

The size and weight of the R6 has been a significant marketing advantage for Agco, he added.

The new machine uses the entire surface of the rotor for threshing, rather than the 160 to 180 degrees found in previous editions and with other manufacturers.

Bien said the feed into this rotor is also important. The inherent advantage of a transverse mounted rotor is that crop doesn’t need to turn a corner to get into the threshing device.

“Some competitors have a feeder house up to 55 inches wide,” he said.

“That’s big. But as their crop moves into the rotor, they have to squeeze it and compress it from 55 inches down to 30 inches in order to jam it into the rotor intake. That’s the pinch point.

“The Gleaner philosophy has always been to keep our crop mat at the same width and as flat as possible where it enters the processor. It’s easier to feed and take advantage of the full 360 degrees of threshing and separating.”

Bien said the width of the crop mat on the S6 and S7 stays at 40 inches.

The mat is fed by two, four-strand feeder chains, as found in Agco’s other high capacity machines, and is delivered at a constant angle to the concave and cylinder. The rear feed chain runs six percent faster than the front feed chain, which gives the rotor a consistent flow of material.

The Gleaner’s reputation for clean samples is based in part on rapid movement through the processor.

“The transverse rotor can thresh and clean in one pass what it takes every other machine two passes,” Bien said.

The other advantage to getting grain out quicker is that space is freed up in the processor for more grain to enter. This quick release strategy gives the combine a higher throughput than might be expected from a machine with this horsepower.

Bien said the crop goes through an exclusive two stage cleaning process when it leaves the rotor wrap.

Distribution augers located just below the housing evenly distribute the crop to the new, larger accelerator rollers, which shoot the grain straight down to the shoe four times faster than the speed of grain dropping by gravity.

As the grain is propelled down toward the grain pan, it’s subjected to a high-velocity air blast from a new 13 inch fan, two inches bigger and 34 percent more airflow than in the R6.

Bien said pre-cleaning with a big air blast is more effective than blowing air to the front chaffer in the sieve. The Super Size combines still use the front chaffer in the sieve, but the shoe is a secondary means of cleaning. The primary cleaning takes place before grain hits the shoe.

“Up there in Canada where you grow so much straw and handle all that residue, you want to get as much of your crop pre-cleaned as possible before it hits the shoe. It’s a huge advantage if you can do that.

“It’s a lot harder to get the (material other than grain) off the shoe in your wet, damp, tough conditions up there. So we blow it off with this high-velocity blast before it gets on to the shoe.”

Bien said grain out of the processor is evenly fed across the entire cleaning shoe by the augers and accelerators. As a result, the S6 and S7 operate on side slopes of up to 23 percent without self-leveling devices.

The new Gleaners use the high volume of air passing below the accelerator rolls to blow chaff out the back of the combine. The chaff spreader features an adjustable tail board and fins to blow out material as it leaves the machine into a wider swath.

There is no stripping of material and no mechanical drives. When used with the hydraulic straw spreader and redesigned spreader curtain, the hydraulic chaff spreader uniformly throws residue from small grains up to 40 feet from the machine. Quick removal of the spreader allows residue to drop.

The S7 Series is designed to reduce the number of belts, chains, augers and gear drives. The low centre of gravity puts most machine parts within easy reach from the ground.

Suction-type hydraulic filters, a single reservoir and a sight-level tube all work to limit service time demands without risking hydraulic system integrity.

An optional auto-lubrication system eliminates that service task, while a newly designed stone trap helps reduce the likelihood of rock damage.

Power comes from the Finnishbuilt Sisu 8.4 litre turbo diesel, delivering 370 horse power with a 398 h.p. power bulge in the S7. In the S6, the Sisu produces 314 h.p. with a power bulge of 344 h.p.

The standard tank is 330 bu., with 390 bu. as an option aimed at the small grain market. The combines use a two-auger unloader design with a 12 inch cross auger feeding a 14 inch unload auger.

The combines feature a fully welded frame and the typical low centre of gravity, which is important in hilly areas but also in putting more power to the ground, according to Agco.

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