Arnold Kelly, right, looks and acts the part of a high-tech startup founder, down to the relentless enthusiasm for his invention and the Vibram Five-Finger shoes. There is, however, a slight age difference between Kelly and the Mark Zuckerberg archetype. Kelly, a retired Princeton professor, cut his chops by designing the Saturn V rocket engines in the 1950s, and his company’s invention is not some smartphone app, but rather an electric spraying nozzle for which he sees applications in agriculture, transportation, and even animal grooming.
Kelly came up with the design for his electrostatic atomizer back in the 1970s when he was an engineer working in an Exxon research lab. The design of the nozzle is simple but highly effective, inspired by a type of rocket engine. “It’s basically a colloid thruster,” Kelly says. The colloid thruster is a low-thrust engine that shoots ionized particles, useful for maneuvering in space if not getting off the ground. When Kelly first built one, he was amazed at how well it worked, and how closely the results matched the calculations he had done beforehand.
Ever since, he has been trying without any luck to get companies interested in using his atomizer. His company, ZYW Corporation, recently left its headquarters in Princeton Corporate Center and Kelly has moved what equipment will fit into the basement of his home. But recent advances in drone technology have given Kelly new hope that his invention will see the light of day. He says that a small lightweight drone using one of his nozzles could apply pesticide to 20 acres of farmland in about an hour, using a soda bottle-sized container of liquid.
Electrostatic spraying is nothing new to industry. The basic idea is to apply an electrical current to a spray of fluid. This gives the particles a negative electric charge, causing them to repel away from one another, widening the spray, and sticking to other objects via static electricity. In researching the history of electrostatic spraying, Kelly found that a French gentleman, a contemporary of Ben Franklin, tried it in 1750 without much success, using a garden hose and a manservant-powered generator made of cat pelts.
Since then techniques have improved somewhat, and electrostatic spraying is used in everything from painting to cropdusting. But Kelly says his device is much more efficient than traditional electrostatic spray nozzles. Kelly demonstrated his rocket-inspired nozzle in the basement of his West Windsor home, where his company is now located.
Using a supply of white oil in a pressurized Coleman camp stove, he ran a very thin stream — about a sixth of a milliliter per second — through one of the nozzles, applying a mild electrical current. The effect was immediate, with the stream disappearing to the naked eye and turning into an invisible, incredibly fine mist that sprayed out in all directions. Almost unnoticeably, particles of oil attached to everything in sight. Kelly laughed, showing off the nearly microscopic dots that had stuck to his glasses during the demonstration. “It gets messy!” he said.
Coating everything in sight with a fine mist of oil is not ideal for domestic settings, but it’s just the thing for spraying pesticides. Currently, pesticides are applied heavily diluted with water, with a few ounces of concentrated pesticide going into dozens of gallons of water per acre. Kelly says that with his nozzle, you could spray the pesticide in its concentrated form without the water. The highly charged particles of the stuff would stick to the plants — on both sides of the leaves — and very little of it would reach the ground and become runoff. “You would only need one ounce per acre,” he says.
Kelly was born in Manhattan to a stay-at-home mom and a father who worked as a machinist, auto mechanic, and navy yard expediter who had dropped out of college to make ends meet during the Great Depression. Kelly says his dad was born with an Italian name, but changed it to Kelly in a fit of pique after his father disapproved of his marrying a Jewish woman. The stubborn streak became evident in his son, who has not stopped promoting the electrostatic spray nozzle despite 40 years of discouragement.
Kelly got his bachelor’s degree at Stevens and then left for California, where he worked for Rocketdyne. “I always wanted to design rockets,” he said, and he soon found himself doing just that as member of that company’s preliminary design team, where he helped design the titanic F-1 engines that were used in the Saturn program.
Later, he earned a doctorate in mechanical engineering at CalTech while working at the Jet Propulsion Laboratory, where he worked on the Surveyor 1 spacecraft, the first vehicle to make a soft landing on the moon.
In 1967 Kelly left JPL to become a Princeton professor, where he worked on electrical propulsion. In 1972 he left for Exxon, where he says he had freedom to research almost anything he wanted. One day he was working on a project involving isotope separation in an attempt to build a uranium laser, and thought that electrostatic spraying would be a good way to do it. Kelly credits his rigorous CalTech education, along with his rocketry background, with allowing him to have the insight that a colloid rocket would make a better electrostatic sprayer than anything that existed.
“This is unique technology,” he says, and jokes, “with this technology and a metrocard, I get to ride the New York subway system.”
Kelly presented his discovery to the board of directors and was baffled when they seemed to have little interest in it. In 1982, he went back to Princeton, where he was a professor again until retiring 20 years ago.
ZYW has been trying to commercialize the technology since the 1980s, and Kelly says he got little support from Princeton for further research or commercialization. He did get contracts from companies that were interested in using the sprayer to make more efficient diesel engines, or for the manufacture of nanofibers, but so far none of that has panned out.
For a while, he tried to market the technology for covering pets with flea repellent and horses with fly spray, but again had no luck.
“I’m a terrible salesman,” Kelly says.
Currently, ZYW consists of Kelly and four part-time employees who also work out of home offices. Most of the heavy equipment that he had in his lab is packed up in a trailer. Kelly says the sprayer is in the “valley of death” between invention and commercialization that many new inventions get stuck in, but he hasn’t given up yet.
“It’s just perseverance,” he says. “It’s my nature to never give up and just keep doing what I know how to do. It’s been rough on the people around me. It’s been rough on my wife, because I’m obsessed.”
Kelly says that the recent VW diesel engine scandal, in which the company admitted to cheating on emissions tests, shows the need to have more efficient combustion technology in that arena. He says his electrostatic sprayer, when attached to fuel injectors, could make diesels run cleaner and more efficiently than they do now.
Kelly says he has had some encouraging news on that front, though he can’t reveal details, as well as interest in the nozzle for aerial spraying with light drones. In the meantime, he is going to keep plugging away in his basement. “It’s like having a mistress except instead of going out and running around, I’m in the basement working. I can’t shut it off. It’s an obsession.”