Senix Measures Vermont Syrup Production

Ultrasonic liquid level sensors monitor maple sugaring to streamline operations and provide local flavor

When Timothy Perkins, Ph.D., became Director of the University of Vermont Proctor Maple Research Center, he understood intuitively why the sugar house operator spent a lot of time running from spot-to-spot to monitor tank levels.

Senix ultrasonic liquid level sensors

Senix ultrasonic liquid level sensors monitor production levels at UVM Proctor Maple Research Center

“In maple syrup production, things can go wrong quickly,” Perkins explained. “If the evaporator tank runs dry, the reverse osmosis (RO) machine shuts down.” This can be a big problem for an industrial process that only operates two months out of 12.

Seeking to make the operation more efficient, Perkins was quick to come up with an idea. Perkins, who had used ultrasonic sensors in other areas of his research, thought liquid level sensors could be a good solution for maple sugaring.

“In a sugar house, ultrasonic sensors were the obvious solution for many reasons,” Perkins said. “The requirements dictate that nothing come in contact with the material in the tanks. You also need something robust because the sensors would have to work in an environment that can be cold or hot and with near 100% humidity.”

Perkins did some research and found that Senix Corporation, a leader in ultrasonic liquid level sensors, was a short distance from the Proctor Maple Research Center in Northwestern Vermont. “We contacted Senix and then worked closely with their staff engineers to develop a solution that fits our needs,” Perkins said

How does it work?

The Proctor Maple Research Center, which operates in part as a test bed for new technologies and processes to improve maple sugaring operations, is using five early generation Senix ToughSonic level sensors. Each of the facility’s three sap tanks has a sensor to monitor levels. There are also sensors on the maple syrup concentrator tank and the tank for permeate, the water produced by the reverse osmosis process.

Each sensor sends a 4-20 mA signal to a panel of fixed vertical bar graphs that can be easily seen by the operator. “Our sugaring operations manager learned to trust the Senix ultrasonic sensors,” Perkins explained. “He doesn’t feel the need to physically check the tanks. He can just look over at the display on the wall and read the tank levels reported by the sensors.”

Senix sensors

Senix sensors send 4-20 mA signals to this panel so tank levels can be monitored by the sugar house operator at a central location.


The sensors help the operator determine if the reverse osmosis machine is keeping up with the amount of sap coming into the evaporator tanks. “It’s very important that the two systems – reverse osmosis and sap evaporation—stay in balance,” Perkins said.

Perkins estimates that installation of the Senix sensors enabled the operator to reduce the time required to check on the tanks by 25% or more and still keep the evaporation and reverse osmosis synchronized. The job is also less physically demanding and safer since the operator no longer has to travel up and down stairs and around the building to check those tank levels by sight.

The Sugar House at the University of Vermont Proctor Maple Research Center.

Future plans

“The Senix sensors have worked flawlessly since they were installed more than 10 years ago,” Perkins said. “We just turn them on when sugaring season begins and they work without interruption until the season ends one or two months later.”

The University of Vermont has been conducting basic and applied maple research since the 1890s. It’s safe to assume that UVM and its Proctor Maple Research Center are going to be involved in maple syrup research, best practices demonstrations, and education for years to come. It’s also safe to assume they will continue to rely on the durability and reliability of Senix ultrasonic sensors.

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