Brush your cares away, go spray

A Wisconsin inventor hopes farmers will be interested in spending $4,000 to equip their spray booms with a new device he says can increase target coverage by 92 percent.

Kurt Kamin has merged his experience as a sprayer operator with his pilot experience to develop a brush that hangs in front of each nozzle to disrupt the wind shear that destroys the spray pattern.

Kamin has used water sensitive paper and Dropletscan software at the University of Nebraska to document coverage increases as high as 92 percent compared to the same nozzles that did not have the benefit of his Pattern Master brushes.

However, a scientist who studied Pattern Master said the results are promising, but inconclusive (see Page 101).

Kamin’s test was conducted using 80-06 Flat Fan Tip nozzles on 20 inch spacings at a rate of 20 gallons per acre, with the sprayer running at 12.5 m.p.h. and the boom 30 inches from the ground.

The software measured 25 percent coverage without Pattern Master and 48 percent coverage with the Pattern Master brushes in place, which is a 92 percent increase.

However, an identical trial conducted the same day but with a rate of 15 gallons per acre found 17 percent coverage with the non-protected nozzles and 27 percent coverage with the brushes installed, for a 58 percent increase.

Kamin observed that every spray boom creates a wind shear factor as the equipment travels through the field. Air hits the boom front and creates a high pressure zone. It accelerates as it goes around the boom because it’s moving into the low pressure zone behind the boom.

“You might be spraying at 12 m.p.h. ground speed on a perfectly calm day, but air moving into that low pressure zone might be 15 m.p.h.,” Kamin said.

Wind shear sends droplets flying in every direction, especially the fine misty droplets, because the tips and spray pattern are located in this low pressure zone. Kamin decided he could increase droplet coverage by reducing wind shear.

“Pattern Master eliminates spray drift because that high air pressure force is not hitting the spray pattern,” he said. “That fine mist which normally gets peeled off into the drift arena now stays in the pattern and goes down to the plants. Every paper test we’ve done shows that we get more water down onto the paper instantly compared to not using the brush.”

Kamin tried documenting air movement with a video camera using a mixture of water and milk in the tank, but the images on his YouTube video still do not fully depict how mist is peeled off the main pattern with an unprotected boom.

However, the water sensitive paper tests do a better job of conveying the information.

He said producers with Pattern Master equipped booms complain about the same problem. They can’t see the pattern anymore so they can’t see whether they’re spraying. Karmin tells them it’s simply because they’ve eliminated the mist.

“We’ve got studies going on right now … at University of Nebraska. We’re trying to get the DRT (drift reduction technology) star rating from EPA (U.S. Environmental Protection Agency). That takes a lot of testing.

“EPA is pretty strict about what they want for test results because we’ve basically changed the physics of what happens when you’re spraying. We’re the only company I know of trying to eliminate wind shear. Other companies build covers.

“Ag Shield had covers 35 years ago. Hardee has an air pressure machine. Willmar just came out with a total shield that fits down over the whole row. But weight is an issue for all these devices. Our brush system weighs one pound per foot of boom.”

Kamin said he used a polyethylene brush because it’s soft. It won’t transfer shock energy back into the boom if it hits the ground, a rock or the crop. As well, a pliable synthetic brush will take a lot more abuse than a solid air deflector.

“The benefits go beyond spray efficacy. It’s better for the environment and everybody concerned when our spray hits the target. And it’s good from an economic point of view because you’ll use less chemical to kill more pests.”

Pattern Master recently won an AE50 award from the American Society of Agricultural and Biological Engineers, which called it one of the year’s most innovative designs for the agricultural industry.

The Pattern Master system uses one brush mounted in front of each nozzle. A 120 foot boom with nozzles on 20-inch spacings can be equipped with a complete set of brushes and mounting hardware for around US $4,000.

For more information, contact Kamin at 715-498-0005 or visit

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