Electromagnetic Water Flow Meter

Function

Water addition accuracy is the final variable determining compaction quality in WMM. At the typical 4–8% OMC window, an error of ±0.5% in added water can shift the mix outside the acceptable range, causing under-compaction and premature pavement failure. The electromagnetic meter's typical accuracy of ±0.3% of reading under calibrated conditions is well within the required control budget. Electrode coating build-up, grounding failure, or converter board degradation can silently drive the moisture loop out of specification without triggering a visible process alarm — making annual calibration verification essential.

Construction & quality

Sensor tube: 316L stainless steel body with PTFE liner for chemically aggressive water or polyurethane liner for standard site water quality. Electrodes: Hastelloy C or titanium, PTFE-sealed, flush-mounted to the bore. Coil: copper windings potted in epoxy. Signal converter: integral or remote-mounted 32-bit microprocessor unit with self-diagnostic functions and empty-pipe detection. Pipe connection: PN16 flanges to EN 1092-1. Electrical supply: 85–265 V AC or 24 V DC switch-selectable.

When to replace

• Flow reading drift greater than 0.5% confirmed by calibrated volume bucket test
• Electrode coating alarm or signal-noise alarm active on the converter display
• Empty-pipe alarm activating when the pipe is confirmed full of water
• Converter display showing communication fault, board error, or no output signal
• Water consumption measured at the meter not reconciling with the calculated OMC addition rate