The thought of a combine fire has kept some former sunflower producers from planting sunflowers again – even with good markets for the right hybrid and the many agronomic benefits of the crop in the rotation.
“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,” said Dan Humburg, former South Dakota State University ag engineer professor and current owner of DSH Engineering, LLC.
Humburg found a unique solution to the problem while researching the problem at SDSU – a kit that can be attached to the combine. He explained how it works to producers at the National Sunflower Association’s (NSA) summer seminar.
“Users of the kits generally report that they do not experience the chronic smolders that they were accustomed to before they attached our kit to their combine,” he said. “Producers who have the kits report that they can operate under conditions that would normally produce fires, and still not have smolders.
At SDSU, Humburg led the research team that found that the white dust that follows the combine in sunflower harvest is the source of the ignition at the exhaust system.
“We identified this material as the white pith inside the stem of the plant. It is as light as styrofoam and gets crumbly after the plant dies,” he said.
“When the stem goes through the combine, this white pith material is reduced to a very lightweight dust that hangs in the air around the combine, sticks to the combine and builds up.”
When this dust is viewed through a high-powered microscope, it is like a sponge with lots of voids and pockets. This means it has a very large surface area.
“That makes it very reactive, and very easy to ignite,” Humburg said.
The lab tests showed that this dust could ignite at lower temperatures than other plant residues; in fact, sunflower debris ignites at temperatures that are 68 to 86 degrees Fahrenheit lower than corn or soybean residue.
“Sunflower producers have known for a long time that they had a more severe risk of fire than producers of corn, soybeans or wheat,” he added.
Temperatures at the turbocharger and some other exhaust system components are high enough that the dust can ignite when it hits these parts on the combine.
That is why many producers find that above a certain engine load they will immediately have fires.
“Below that, the engine load the exhaust system may be cool enough to avoid ignition, but then the producer only has part of the machine capacity available and is still at risk for possible fires,” Humburg said.
The kit designed and offered by DSH Engineering is a “comprehensive solution to the exhaust system problem, and a game changer,” he said.
On the kits, an enclosure is used to box in the hot exhaust components, and a pressure blower pulls a stream of air through a filter to remove all of the white dust.
“The clean air is pumped by the blower into the enclosure around the exhaust system, and the clean air flow into the enclosure keeps the dusty air from being able to get near the hot parts,” Humburg said.
DSH’s system is directed at the exhaust system.
“It will not prevent fires that originate at hot bearings, or electrical system problems,” he said. “I always advise producers to remain vigilant for possible fires from these sources.”
Are the kits like the chimneys that other companies already produce?
“Our kits are absolutely not a chimney,” Humburg said. “The chimney is something that can help under some circumstances.”
Chimneys take in cleaner air from higher in the sky, and that reduces the amount of white dust that passes through the radiators and is blown over the engine.
“I have been told by producers that this works if there is the right amount of wind,” he said. “Under still conditions, the dust rolls up and over the system and can still result in fires. I also suspect that there are times when a quartering wind can cause dust to enter the engine compartment from areas that bypass the radiator air flow and cause smolders.”
DSH Engineering is currently producing kits for Case IH models from the 8010 upward through the 9250. In addition, kits have been developed for the John Deere 9650, 9760, 9670 and 9770.
These kits may also fit other models that use the same engine and exhaust system.
The NSA and the South Dakota Oilseeds Council funded the research on sunflower combine fires and the solution kits.
Kits for use in fall 2019 should be ordered soon as some of the components have lead times of up to 14 weeks.
Producers wanting a system, or wishing to ask questions can contact DSH Engineering, LLC at (605) 693-3761.