BRISTOL – A local man has developed an air purifier that puts up a “curtain” to shield people from coronavirus particles.
The air purifiers, designed by Paul Bemis, are in use at the Minot-Sleeper Library in Bristol and Plymouth General Dentistry.
The “Clean Air Curtain” purifiers use two technologies that the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends in dealing with the coronavirus: a thick, fine HEPA filter and ultraviolet light.
Bemis, said the virus’ molecule is about 1.2 microns in size, significantly larger than the .1 micron-sized particle that his purifiers allow to pass through.
Placed at waist height, which is within a human being’s breathing zone, the purifiers emit a stream of air that knocks down particles and then removes them, Bemis said.
As measured by a particle counter, the air that comes out of the purifier, Bemis noted, is on the lower limit of “good” – which is zero to 12 micrograms per cubic meter for particles 2.5 microns in diameter or smaller. He said it may be even cleaner than the fresh air in the woods outside his home, which recently registered at around 6 micrograms.
A native of Warren, Bemis hopes to outsource the manufacture of his air purifiers, with the goal of his company, Air Cleaners Inc., leasing them to customers under a contract that includes all servicing of the unit, replacement of its 3½-inch thick filter, and upgrades as they become available.
He is already working on ways to make the air purifiers “smart” so they can indicate when an adjustment or repair is needed.
In a nod to his prior career, he said the air purifiers are, in essence, “a computer with a fan and filter.”
After graduating from Plymouth Regional High School in 1974, Bemis enrolled at Keene State with the goal of becoming an industrial arts teacher.
But Keene State was just a beginning for Bemis, not an end.
“I learned to study, to do math and I got an ‘A’ in physics,” he said, which inspired him to transfer to the University of New Hampshire, where he received a degree in mechanical engineering.
“I was so naïve” at UNH, Bemis recounted with a laugh, saying that when he was told he would have to take three classes in mechanics, he thought he’d be learning about internal-combustion engines. Instead, the classes were in “Newtonian mechanics.”
After graduating from UNH, Bemis went to work for a company along Massachusetts’ Route 128 high-tech corridor.
“My first job,” he said, “was packaging … putting a box or a fan on something,” usually a computer.
Bored with the work, Bemis enrolled at Northeastern University and took night classes to earn a degree in electrical engineering, and later an MBA, also from Northeastern.
His employer was bought by HP, for which Bemis then worked 10 years and rose to become head of what is now known as the “cloud computing” division.
Bemis later joined Fluent, a company in Lebanon which was the world’s largest maker of airflow-modeling software.
When Fluent was bought eight years later, Bemis struck out on his own, founding Applied Math Modeling in Concord. AMM’s customers have included AT&T, Verizon and the Argonne National Laboratory, all of which were concerned about getting heat out of their data centers.
Last spring, AMM, on a pro bono basis on behalf of ASHRAE, began modelling the transmission of pathogens “from one person to another in the air.”
“We realized that we can reduce the transmission by cleaning the air,” Bemis said, and from there the idea of what would be the Clean Air Curtain purifiers was born.
After making several prototypes in his basement, Bemis said he searched for a contractor manufacturer before finding Spinnaker Contract Manufacturing, Inc., which is located in Tilton.
“We did a short run of five units and then went straight into production,” said Bemis, who said 100 units, at a cost of about $1,500 each, have been sold so far.
“It’s an all-New Hampshire solution,” Bemis said, adding that he believes the purifier will become “a competitive differentiator” for any business or entity that wants to keep visitors or customers safe indoors.
He envisions restaurants and gyms, for example, would advertise the fact that they are using his air purifiers, maybe even featuring a particle-count display, to assuage concerns about air quality.
Dr. Joan Kirschner, DDS, said Plymouth General Dentistry, which had already been using a HEPA-filtered air cleaner at each treatment chair, chose to “double up” by installing six Clean Air Curtain air purifiers.
“Some patients will ask what (the air purifiers) are and what they do and many people will thank us for having the units there,” said Kirschner.
Brittany Overton, the director of the Minot-Sleeper Library, said in an email that the library’s two Clean Air Curtain air purifiers there complement its existing COVID-19 protocols.
“Having devices that clean the air in the library seemed an important next step in keeping everyone safe, especially when we know that much of the COVID-19 virus is transmitted through the air,” Overton wrote.
“Ever since the air cleaners were taken out of their boxes, plugged in and turned on, we’ve seen a difference in our air quality,” Overton said.