WEYBRIDGE — At the same time that forest science students at the Patricia A. Hannaford Career Center are learning the art of maple syrup production they’re also attempting to revolutionize it with a device to measure sap flow.
Teacher Aaron Townshend and student John Bent call it the “maple weir,” and they, along with Hannaford STEM student Will Larocque, are field-testing it this week at the Lemon Fair Road sugarhouse operated by the Career Center in Weybridge.
A weir is a low dam — often featuring a V-shaped notch — that raises a stream or river’s water level in order to regulate or measure its flow.
If it works, the maple weir will measure the flow of sap through a sap line and transmit the data to a computer in the sugarhouse. If one day it becomes standard equipment, the invention could save the maple syrup industry a lot of time and money in inspecting and maintaining lines.
“This has been years in the making,” said Townshend, a forestry and natural resources instructor at the Career Center. “Students came up with the idea and they’ve developed this to solve a problem.”
It all started when Townshend called a local maple researcher and asked him if he thought it would be possible to measure sap flow in the field. The researcher didn’t suggest it was impossible, but he didn’t hold out much hope for the idea.
“This just piqued my students’ interest,” Townshend said. “So I took the problem and gave it to them.”
According to a lab paper written last year by students Jacob LaFleche and Adam Whitcomb, measuring sap flow could help sugarmakers more easily locate leaks, sags and frozen lines. For operations with tens of thousands of sap lines, such an invention could translate into a big-time savings. The device could also help them understand exactly under what circumstances sap runs at its best.
Previous classes have tested prototypes in a classroom setting, but Bent and Larocque, who joined the project this semester, have taken it to the finish line.
“Mr. T handed me this box of stuff and said ‘Here, let’s make this happen,” said Bent, who is a junior at Mount Abraham Union High School.
Using PVC, wire and 3-D printing, Bent has produced a series of prototypes and built a customized casing. In another part of the building, Larocque worked out the electronics and software.
In a demonstration on Monday Bent provided the Independent with a thorough and authoritative description of the device, which involves proprietary technology.
If this week’s testing works, Townshend plans to meet with industry leaders to talk about viability and mass production.
“Ideally, these would be cheap enough to install on every main (sap) line,” Bent said. “Someday we’d also like it to be able to measure temperature and vacuum pressure.”
Bent is well acquainted with the industry — he’s been working at Starksboro’s Bear Cobble sugarhouse for the last three years.
“I started off doing line work in the woods,” he explained. 
A SADDLE VALVE connects a mainline (on right) to the transmission line that delivers sap to the Hannaford Career Center’s sugarhouse in Weybridge. Students have invented a meter (not shown) that would measure the flow of sap through these lines.
Independent photo/Christopher Ross
Then he discovered that he’s really better with the mechanical stuff, he said, so even though he enjoys being out in the woods, he spends a lot of time performing maintenance in the sugarhouse. Over time he has learned the operation’s entire maple production system, which includes about 30,000 taps. Last summer he helped replace 12,000 lines.
On Monday Bent shared a time-saving technique with fellow students who had spent the morning in the woods examining lines for leaks, nicks and “squirrel chews.”
A few feet from where the maple weir will be installed, he pointed out the valve that connects a three-quarter-inch main line with the one-inch transport line.
“You can’t tell if leaky saddle valves are leaking by just looking at the loop,” he told fellow student Sam Klingensmith. “You turn (the valve) off, wait like 30 seconds or a minute or whatever and then you turn it back on real slow to see if you can hear.”
Bent and Klingensmith bent their heads over the valve and listened.
“There’s a little leak on that, did you hear it?” said Bent.
“Yeah, I heard it,” said Klingensmith, who shook his head. “So we could have just done that instead of checking every single…”
Bent nodded.
“Yeah. When you’ve got 30,000 taps, you learn tricks like this really quick.”
Maple syrup production makes up only one unit of the forest science courses Townshend teaches every year at the Career Center.
Students learn a wide variety of forest management skills that earn science and elective credits. They then take what they learn and compete with other students around the state in events sponsored by FFA (Future Farmers of America) and other organizations.
Bent, who won first place in an FFA soil science competition last year, will compete in several events at the FFA state convention in May and in another competition elsewhere called Game of Logging, which provides training and competition in various forestry skills, including chainsaw use.
Townshend said Bent’s natural abilities and interests make him a great fit for a project like the maple weir. 
“You can just see it in certain kids,” he said. “They’re the ones who are going to really get into it, really do the work. John’s got his own workspace out there and he’s doing it, he’s problem-solving.”
Reach Christopher Ross at [email protected].