How does the LGF-PA66 magnetic flow meter protect against empty-pipe operation? Can it measure accurately in partially filled pipes?

A magnetic flow meter works on Faraday's law of electromagnetic induction, and accurate measurement requires the medium to completely fill the pipe cross-section. The LGF-PA66 is a full-bore magnetic flow meter: with an empty or partially filled pipe there is no continuous conductive liquid between the electrodes, the induced voltage becomes distorted, and readings jump or drift from zero. Over time the electrodes also lose the wetting protection provided by the liquid.

Empty-pipe conditions are handled on three levels:

• Process design: install the LGF-PA66 at a low point of the line or in a downstream section with stable back pressure so the pipe stays full; add a control valve or weir downstream to raise back pressure if needed.
• Function settings: enable empty-pipe detection so the meter cuts its measurement output and raises an alarm once electrode coverage drops below the set threshold, keeping distorted data out of billing records.
• Condition monitoring: in intermittent pumping duties, use an EC32 RTU to log empty-pipe alarm timestamps and compare them against pump start/stop logic to separate process-driven empty pipes from equipment faults.

If the duty itself is open-channel gravity flow or a drainage pipe that frequently runs half full, do not force a full-bore magnetic meter into the job. A Doppler radar flowmeter that measures level and surface velocity together, computing flow from the level-area method, is the better fit.

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