Can the LGF-PA66 electromagnetic flowmeter measure bidirectional flow accurately in sewers with frequent backflow?

When tidal backwater or a rising downstream level pushes flow backwards in a storm or sanitary sewer, the metering point must measure in both directions. The LGF-PA66 works on Faraday's law of induction: the polarity of the induced voltage follows the flow direction, so the velocity signal carries a natural sign — it measures forward and reverse flow without any mechanical direction-sensing device.

The converter keeps separate forward and reverse totals and also outputs net flow (forward minus reverse). Reports can show the reverse volume separately, which quantifies external water intrusion and backflow frequency. With the EC32 RTU the forward total, reverse total, net flow and instantaneous direction all enter the data stream, so the platform can analyse backflow patterns by pumping-station operating period and support interception decisions.

Installation points:

• Choose a pressurised, always-full section such as a pump discharge line. Electromagnetic meters cannot measure partially filled gravity pipes — for those use a Doppler radar flowmeter or an ultrasonic open-channel solution instead.
• For bidirectional flow keep straight runs of at least 5D on both sides so the flow profile is stable in each direction.
• Sewage deposits sludge easily: place the meter close to the pump station so pump scouring keeps the tube clean, and inspect the electrodes periodically.

Bidirectional operation does not change the accuracy specification — the LGF-PA66 holds ±0.5%（DN50-100） of reading in both directions and runs reliably for years with empty-pipe detection enabled. For more information, please visit our product page or contact our technical team.