Electromagnetic Flowmeters

Electromagnetic Flowmeters

Electromagnetic flowmeters (magmeters) measure volumetric flow of electrically conductive liquids using Faraday’s law of induction. A magnetic field is generated across the meter tube and the moving conductive fluid induces a voltage at electrodes; the induced signal is proportional to flow velocity and therefore to volume flow. With a full-bore design and no moving parts, the measurement is inherently well suited to continuous service in demanding process and utility environments.

Because the measuring principle is largely independent of pressure, density, temperature, and viscosity, magmeters maintain stable performance across operating changes that can challenge inferential technologies. They can also meter liquids with entrained solids, such as ore slurry or cellulose pulp, and they preserve a free pipe cross-section that can support CIP/SIP cleaning and pigging where the installation requires it.

Typical applications include water and wastewater treatment, distribution and district-metering, and general water-management duties. In process industries, they are routinely applied to acids, alkalis, and other conductive chemicals, as well as to filling, dosing, and general liquid monitoring. In mining and tunnel construction, robust magmeters are often used for highly abrasive slurries and sand-water mixtures when solids handling is a key requirement.

Successful deployment depends on confirming minimum conductivity, selecting liners and electrode materials compatible with chemical attack and abrasion, and applying proper grounding/bonding to control electrical noise. Installation practice should maintain a full pipe, manage entrained gas where possible, and avoid locations that can create partially filled conditions or unstable velocity profiles. These steps protect signal stability and reduce the risk of coating-related drift.

Magmeters integrate cleanly into modern automation via conventional and digital interfaces, and their maintenance model is simplified by the absence of moving parts. Where hygienic design is required, full-bore construction and cleanability support validated cleaning regimes, while in large-diameter networks the same principle scales to very large line sizes for consistent measurement across an installed base.

Field Instruments & Controls, Inc. an exclusive authorized representative of sales and service for Endress+Hauser.