Engineering ingenuity: SDSU researchers develop device to prevent combine fires

Farm Forum

Most sunflower growers know during harvest it’s not if they will have a combine fire, but when. Though fires also occur with soybeans, “It’s not endemic like in sunflowers,” explains SDSU Agricultural and Biosystems Engineering professor Dan Humburg. He adds, “Some producers won’t grow sunflowers because they don’t want to put their combines at risk.”

In the fall of 2011, a team of SDSU agricultural engineers set out to analyze the problem and figure out how to prevent the fires through funding from the South Dakota Oilseeds Council. As a result, the engineering team has designed a device that can be fitted onto a combine to drastically reduce – and may even eliminate – these fires.

Before researchers could prevent the fires, they first had to learn more about what was causing the fires. Graduate student Joseph Polin and assistant professor Zhen Grong “Jimmy” Gu investigated which parts of the sunflower plant ignite and at what temperature.

Polin’s lab work found a large part of what was sticking to the combine was the white pith from inside the stem. “It breaks down and is drawn into the fan that pulls air through the radiator to cool the engine. We believe a portion of this dust ignites when it hits the turbocharger and exhaust system,” Humburg explains.

Anecdotal information from producers supported this scenario. Farmers were finding scattered, smoldering fires on the side of the combine downstream from the radiator blast, especially under windy conditions.

By the 2012 harvest season, the agricultural engineers had developed a prototype system that uses a fan to pull outside air through a filter. The clean air is pushed through a duct into an enclosure surrounding the turbocharger and exhaust manifold.

“This clean air enters the same hot environment, but it contains no dust to ignite,” Humburg notes. Additionally, the outside of the patent-pending system stays within a safe temperature range.

Humburg credits Onida farmer Scott Foth for helping SDSU researchers better understand the problem. Foth used the research team’s prototype on his Case IH 8120 combine during the 2012 harvest. He tested an updated version during fall 2013’s harvest.

“I’ve been fighting these fires for years,” Foth says. “If we can get through this season without a fire caused by the exhaust, I will be totally convinced that this is the answer so many farmers have been looking for.”

The expertise and passion of the SDSU team produced results that Brad Bonhorst, former president of the South Dakota Oilseeds Council, describes as “one of the best uses of checkoff dollars that I’ve ever seen.” He says, “Those fellas took a relatively small amount of money and came up with some really impressive results.”

In 2013, the National Sunflower Association took over funding the project, which allowed researchers to expand the project to two additional operations – another Onida farmer who has a John Deere 9770 combine and one in Hazen, N.D, who owns a Case IH 8230. “All three models have different exhaust sizes and configurations,” Humburg explains, so the exhaust enclosure system has to be redesigned for each combine. “That’s the limitation.”

Based on their research findings, Humburg hopes this type of equipment will eventually become standard on future combines.

To view this and other articles found in the SDSU Agricultural Experiment Station 2013 Annual Report, visit