Electromagnetic Flowmeters

Electromagnetic Flowmeters

Electromagnetic Flowmeters measure volumetric flow of electrically conductive liquids using Faraday’s law of induction. A magnetic field is generated across the measuring tube; as charged particles in the liquid cross that field, an induced voltage is created and tapped by measuring electrodes. The induced signal is directly proportional to flow velocity and therefore to volumetric flow. Pulsed DC excitation with alternating polarity supports a stable zero point and helps the measurement remain robust with multiphase or inhomogeneous liquids and at low conductivity.

Because the measuring principle is largely independent of pressure, density, temperature, and viscosity, electromagnetic measurement delivers consistent results across wide operating ranges without complex compensation. The tube remains unobstructed, so there are no moving parts and no intrinsic pressure loss associated with the meter body. Maintenance demands are typically low, and the free cross-section supports pigging as well as CIP/SIP cleaning strategies in hygienic service.

Magmeters perform well in abrasive and solids-laden duties. Ore slurry and cellulose pulp are examples of services that can be metered effectively because the signal derives from bulk velocity rather than a mechanical element. A wide range of nominal diameters (DN 2 up to large conveyance sizes) supports consistent instrumentation from compact skids through main transfer lines.

Typical applications include water and wastewater, process and utility water distribution, mining and mineral processing, pulp and paper stock lines, chemical transfer, and food and beverage processes. Material selections for liners and electrodes align the meter with corrosive media and erosive duty, while the open bore and cleanable design help maintain sanitary integrity and long-term stability in production environments.

Key constraints are that the medium must be sufficiently conductive and the meter must operate in a full pipe. Installation practices address grounding and bonding, electrode orientation, and avoidance of upstream air entrainment that can create empty-pipe conditions. When those prerequisites are met, electromagnetic technology provides stable, maintenance-light flow measurement across a broad range of line sizes and industries.

Forberg Smith, an exclusive authorized representative of sales and service for Endress+Hauser.