Electromagnetic Flowmeters

Electromagnetic Flowmeters

Electromagnetic flowmeters measure volumetric flow of electrically conductive liquids using Faraday’s law of induction. Field coils generate a magnetic field; as the liquid’s charged particles cross it, a voltage is induced and tapped by electrodes, directly proportional to flow velocity and therefore to volumetric flow. Excitation with pulsed direct current and alternating polarity helps stabilize the zero point and improves robustness in inhomogeneous liquids and low-conductivity conditions.

This approach is attractive because the measuring principle is largely insensitive to pressure, density, temperature, and viscosity, so calibration remains stable even when process conditions change. With no moving parts and a full-bore pipe, electromagnetic meters are typically low-maintenance, and the free cross-section supports hygienic cleaning (CIP/SIP) and pigging strategies where required.

Electromagnetic meters require a minimum fluid conductivity and therefore target water-based and other conductive services rather than hydrocarbons. Within their operating envelope, they handle difficult mixtures well, including liquids with entrained solids - such as ore slurry or cellulose pulp - where abrasion resistance and signal stability are critical. The available size range is broad, spanning small process lines to very large pipelines (e.g., DN 2 to DN 3000 in many portfolios).

Typical applications include raw and treated water, wastewater, utility and cooling water, acids and alkalis, pulp and paper stock, mineral slurries, and other abrasive services. They are also widely used for filling and dosing tasks and for precise measurement in custody-transfer services involving conductive liquids, with strong adoption in water management, processing, life sciences, and food operations.

Selection centers on lining and electrode material compatibility, grounding and installation practice, and the presence of air, coating, or partially filled pipe conditions. When combined with embedded diagnostics and digital communications, electromagnetic flowmeters support in-situ verification and targeted maintenance that protects both measurement integrity and availability across long service intervals. Empty-pipe detection, electrode coating management, and robust grounding/bonding practice are common considerations for maintaining signal quality in aerated or high-solids service.

Engineered Equipment Company, a leading supplier of specialized industrial equipment.