Electromagnetic vs. ultrasonic flow meters for DMA district metering — how does the LGF-PA66 compare with clamp-on ultrasonic?

A DMA district metering point must answer two questions: how much water was supplied by day, and how much leaked away at night. Night-flow analysis demands excellent low-velocity stability — exactly where the two technologies diverge.

• Principle and accuracy: the LGF-PA66 measures full-bore volumetric flow by Faraday's law at ±0.5%（DN50-100）, independent of flow velocity — it stays stable even below 0.1 m/s at night. Clamp-on ultrasonic infers flow from transit-time differences and is affected by pipe scale, linings, and air bubbles; field accuracy typically wanders between ±1% and ±3%.
• Installation: clamp-on ultrasonic needs no pipe cutting or shutdown — good for temporary checks and leakage surveys. The LGF-PA66 requires a line break to install, but once in it serves as a long-term fiscal meter; at one-third the weight of a stainless meter it is easy to set in a chamber.
• Long-term stability: the electromagnetic meter has no moving parts and tolerates scaling (periodic electrode cleaning suffices), with small drift over a 10-year cycle; ultrasonic transducers age and coupling gel dries out, both shifting the data.

The common field pattern: use the LGF-PA66 as the settlement-grade district meter with an EC32 RTU uploading 4G data every 15 minutes, and use portable clamp-on ultrasonic for network surveys and suspected-leak localization. They complement rather than replace each other; on tight budgets, clamp-on can bridge small branch lines below DN50 first.

For more details, please visit our product pages or contact our technical team.