Newswise — Harvesting sunflowers requires nerves of steel. “It’s not if we will have a combine fire, but when,” according to producers. An answer to this nerve-wracking problem may be within their grasp. A device designed by a team of South Dakota State University agricultural engineers has proven to drastically reduce and perhaps even eliminate these fires.
“Sunflower producers have known for a long time that they had a more severe risk of fire than producers of corn, soybeans or wheat,” says professor Dan Humburg, who led the agricultural engineering research team. His colleague, Kevin Dalsted, coordinated data-gathering and input from area producers and assisted with technical and design work.
In fall 2011, the team set out to analyze the problem and figure out how to prevent the fires through funding from the South Dakota Oilseeds Council. Protecting machines with vigilance Though fires do occur with soybeans, he says, “it is not endemic like in sunflowers. Some producers won’t grow sunflowers because they don’t want to put their combines at risk.” He estimated the cost of a replacing a combine at $300,000, without the heads and other needed accessories.
For sunflower producers, harvesting requires constant vigilance. “Most farmers keep a truck at the end of the field with a water tank to put out a catastrophic fire,” Humburg explains. On the combine, they typically carry water to extinguish small smoldering areas.
One sunflower grower in central South Dakota told Humburg he has become attuned to the odor just before a fire ignites. “He’s so sensitive to it that he knows exactly what to smell for to be on guard,” Humburg explains. This exemplifies “the tension they’re under all the time.”
Finding the source of firesGraduate student Joseph Polin and assistant professor Zhengrong Gu investigated which parts of the plant ignite and at what temperature. The researchers ground the outer shells of the stem, the plate-shaped head and the white pith in the center of the stem, and then compared their chemical properties to those of the dust gathered from combines. A large part of what was sticking to the combine was the white pith, Humburg explains. It breaks down and is drawn into the fan that pulls air through the radiator to cool the engine. “A portion of this dust ignites when it hits the turbocharger and exhaust system,” Humburg says. “Once a fire starts, it’s easy for a spark to be relocated.” Many machine components including fiberglass shields, wiring harnesses, flexible hoses and plastic fuel tanks can burn.
Polin and Gu found that sunflower debris ignites at temperatures that are 68 to 86 degrees Fahrenheit lower than does corn or soybean residue. Farmers monitor fuel usage and rated engine load to identify the point at which they will experience combine fires immediately, Humburg explains. “If they push engines beyond this threshold, they have a higher likelihood of a fire,” Humburg says. A greater engine load will increase the exhaust system’s temperature. Designing preventive measuresBy 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 contains no dust to ignite,” Humburg notes. Additionally, the outside of the patent-pending system easily stays within a safe temperature range.
Humburg credits producer Scott Foth for “contributing much to our understanding of the problem.” The Onida farmer used the research team’s prototype on his Case IH 8120 combine during the 2012 harvest. He tested an updated version last fall. “I’ve been fighting these fires for years,” Foth says. “I’ve experimented with many things that helped, but until now, nothing really solved the problem completely.”
Last year when a seal went out on the prototype system, he reports, “we had a fire every day while the device was not operating.” Since then, Foth has experienced only one fire, which he speculates may have been caused by a bearing failure. “Being able to go full speed and use all the capacity of the combine to get the crop in is a huge relief,” says Foth. Producing promising resultsThe expertise and passion of the SDSU team produced results that Brad Bonhorst, former president of the Oilseeds Council, describes as having “great potential to solve the problem.” “This was 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. “That doesn’t happen very often,” Bonhorst explains.
The increase in funding allowed the researchers to expand the project to more two 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 fan and filter system has to be redesigned for each combine. “That’s the limitation.”
To build their case for the device, the researchers are looking at other crops, such as chickpeas, lentils and even soybeans, that create an elevated fire hazard for producers.
Coping with new emission standardsTo meet new emission standards effective in 2014, combine manufacturers are focused on cleaning up diesel exhaust, Humburg notes. Some equipment designs use a diesel particulate filter to trap the black soot, and then run the component hot enough to burn the material away, creating yet another danger area when it comes to sunflower dust. Once the new combine models can meet the exhaust requirement, this will be one of the issues manufacturers must address, he explains. Manufacturing devices for combinesThe challenge now is figuring out how to get this device into the hands of the producers, according to SDSU’s director of technology transfer Will Aylor. This spring Aylor will try to forge an agreement with a fabrication company to manufacture the device for existing combines, as perhaps the quickest way to get the technology into the fields. The importance to producers is clear, says Aylor. “As a land-grant institution, we need to promote as much as possible for the good it can do for producers. It’s our mission.”
Humburg hopes that this type of equipment will become standard fare on combines.
About South Dakota State UniversityFounded in 1881, South Dakota State University is the state’s Morrill Act land-grant institution as well as its largest, most comprehensive school of higher education. SDSU confers degrees from eight different colleges representing more than 175 majors, minors and specializations. The institution also offers 29 master’s degree programs, 13 Ph.D. and two professional programs.
The work of the university is carried out on a residential campus in Brookings, at sites in Sioux Falls, Pierre and Rapid City, and through Cooperative Extension offices and Agricultural Experiment Station research sites across the state.
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