Instrument Mesurement Knowledge

What is an Electromagnetic Flowmeter?

Views: 179     Author: Site Editor     Publish Time: 2024-07-09      Origin: Site

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A magnetic flow meter (mag meter, electromagnetic flow meter) is a transducer that measures fluid flow by the voltage induced across the liquid by its flow through a magnetic field. A magnetic field is applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The physical principle at work is electromagnetic induction. The magnetic flow meter requires a conducting fluid, for example, water that contains ions, and an electrical insulating pipe surface, for example, a rubber-lined steel tube.


If the magnetic field direction were constant, electrochemical and other effects at the electrodes would make the potential difference difficult to distinguish from the fluid flow induced potential difference. To show this in modern magnetic flowmeters, the magnetic field is constantly reversed, cancelling out the electrochemical potential difference, which does not change direction with the magnetic field. This however prevents the use of permanent magnets for magnetic flowmeters.

Electromagnetic Flow Meters Measuring Principle

Faraday's law of induction states that a metal rod moving in a magnetic field induces electrical voltage. This dynamo principle also governs the way electromagnetic flowmeters work.

Measuring Principle

As soon as the electrically charged particles of a fluid cross the artificial magnetic field generated by two field coils, an electric voltage is induced. This voltage, tapped by two measuring electrodes, is directly proportional to the velocity of flow and thus to the flow volume.


The magnetic field is generated by a pulsed direct current with alternating polarity. This ensures a stable zero point and makes the flow measurement insensitive to multiphase or inhomogeneous liquids, as well as low conductivity.

Special Features of Electromagnetic Flow Meter

  • High Precision Measurement: The ARTang flow meter offers exceptional accuracy in measuring the volumetric flow of conductive fluids, making it suitable for critical applications where precise flow data is necessary.

  • No Pressure Drop: Its inline design ensures there is no pressure loss within the system, preserving fluid characteristics and ensuring efficient process flow.

  • Durability: This device is constructed with a variety of electrode materials and liners, allowing it to withstand harsh conditions, including corrosive environments and high-temperature applications. This ensures a longer lifespan and minimal maintenance requirements.

  • Low Maintenance: With no moving parts and a robust design, the ARTang requires minimal maintenance, reducing downtime and operational costs.

  • Versatile Integration: Compatible with various communication protocols, the ARTang can be easily integrated into existing control systems, facilitating real-time monitoring and process optimization.

  • Electrode Materials: Options include stainless steel, Hastelloy, platinum, and tantalum, catering to different fluid types and process environments.

  • Liner Materials: Available liners include PTFE, PFA, and ceramic, allowing the EPS to handle aggressive chemicals and high temperatures.

  • Communication Protocols: Supports Modbus, Profibus, HART, and other industrial communication standards for seamless integration into process control systems.

Advantages of Electromagnetic Flow Meter

  • The measuring principle is virtually independent of pressure, density, temperature and viscosity

  • Even fluids with entrained solids can be metered, e.g. ore slurry or cellulose pulp

  • Wide range of nominal diameters (DN 2 to 3000; 1/12 to 120")

  • Free pipe cross-section: CIP/SIP cleanable, piggable

  • No moving parts, maintenance-free

Disadvantages of Electromagnetic Flow Meter

  • Can not be used to measure gases, steam and liquids containing a large number of gases;

  • can not be used to measure the conductivity is very low liquid media, electromagnetic flowmeter also can not measure petroleum products or organic solvents and other media;

  • can not be used to measure high temperature media. Currently by the general industrial electromagnetic flowmeter measuring tube lining materials and electrical insulation material limitations;

  • Electromagnetic flowmeter is susceptible to external electromagnetic interference.

ARTang Magnetic Flow Meter of Applications


There are a number of applications of electromagnetic flowmeters in the Artang range. The Type Aimag S version with a stainless steel sensor can be used in applications with high pressures of up to PN16 and high temperatures of up to 150°C. Furthermore, the TypeAimag C with Alloy C22 electrodes has been designed for applications with aggressive fluids (chemicals) and especially sea water applications.

Magnetic flow meters are crucial across numerous industries due to their versatility and precision, particularly in applications involving conductive materials. These devices play a vital role in ensuring accurate measurements and maintaining safety and quality standards across various sectors. They are most suitable for industries dealing with conductive fluids, ensuring optimal performance and reliability.

Chemical Processing: Ensuring precise measurements for complex chemical reactions and maintaining safety and quality standards.

Industrial Water Management: Efficiently managing water usage and treatment processes, ensuring sustainability and regulatory compliance.

Mining & Metal Processing: Monitoring slurry flows and other challenging applications with high accuracy and reliability.

Pulp and Paper: Managing flow rates in pulp production and paper manufacturing processes, ensuring consistency and quality.

Electromagnetic Flow Meter

Whereas, Type Aimag A/Aimag D full bore mag flowmeters are designed for water treatment and general purpose applications. Combined with an actuated valve, the complete full bore mag flowmeter Type Aimag H can control high-precision dosing operations and flow measurement in food and beverage or pharmaceutical applications, which is suited to Clean in Place (CIP) applications. 

What are the Different Types of Magnetic Flow Meters?

Insertion type electromagnetic flowmeter

Insertion type electromagnetic flowmeter is a reliable measuring instrument for liquid flow measurement in large and medium caliber pipes (DN25-DN3000mm). Meet the needs of many different applications. Flow rate measurement range: 0.1m/s-15 m/s, protection grade: IP68, for pipeline electromagnetic flowmeter in the large pipeline installation difficulties, costs and other defects.

Sanitary electromagnetic flowmeter

Sanitary electromagnetic flowmeter adopts a new type of sanitary lining materials and lining process, in line with the hygiene requirements of the food industry, while the use of stainless steel shell and stainless steel clamp connection, easy to electromagnetic flowmeter rapid disassembly, cleaning, so that the electromagnetic flowmeter is not easy to be contaminated in the process of use, and can effectively prevent the measurement of the fluid residue in the measurement pipe accumulation.

Battery-powered Electromagnetic Flow Meter

A battery-powered electromagnetic flow meter is designed for applications where a power supply is unavailable or impractical. It operates using an internal battery, making it ideal for remote locations, temporary flow measurement, or areas with unreliable power sources.

Split-type Electromagnetic Flow Meter

A split-type electromagnetic flow meter (also known as a remote-type electromagnetic flow meter) consists of two separate components:

  1. Sensor (Flow Tube) – Installed in the pipeline to measure flow.

  2. Transmitter (Converter) – Mounted separately, connected via a signal cable for data processing and display.

Electromagnetic Flowmeter Installation Guide:

1. Horizontal and vertical installation: the sensor can be installed horizontally and vertically, but should ensure that to avoid the impact of sediment and air bubbles on the measuring electrode, the electrode axial to maintain the level is good. Vertical installation, the fluid should flow from bottom to top. The sensor can not be installed in the highest position of the pipe, this position is easy to accumulate air bubbles.

2. Ensure full pipe installation: ensure that the flow sensor in the measurement, the pipe is full of the measured fluid, can not appear non-full pipe state.

3. The sensor can not be installed in the inlet of the pump: To avoid negative pressure, the sensor can not be installed in the inlet of the pump, but should be installed in the outlet of the pump.

4. Inlet straight pipe section and outlet straight pipe section: the more ideal installation location should be selected before and after the measurement point has enough straight pipe section. Import straight section should be ≥ 10 × DN, export straight section ≥ 5 × DN.

5. Grounding: electromagnetic flowmeter must be properly grounded in order to eliminate electromagnetic noise and ensure the safety performance of the instrument.

6. Installation environment requirements: should ensure that the installation site around no vibration, no strong electromagnetic field.

If you would like any more information about our Electromagnetic Flowmeters please contact us.