Home > Knowledge > Content
How electromagnetic flow meter works
Dec 24, 2018

A common flow meter (like a differential pressure and positive displacement flow meters) is the magnetic flow meter, also technically an electromagnetic flow meter or more commonly just called a mag meter. 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 mitigate 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.

It is suitable for the conductive medium whose conductivity is more than 5us/cm, and it not only has a wide nominal diameter range, but also adapts to various actual environmental conditions. In addition, it possesses a variety of power supply methods and signal output using the standard RS-485 serial communication interface, as well as supports the international standard MODBUS-RTU protocol and GPRS and other wireless or wired communication network methods, and also has the accumulative pulse equivalent output. It provides the wireless meter reading system that can access the network in a long-distance (computer management software and databases).


Functional characteristics

Excellent measurement repeatability and linearity, Good reliability and anti-interference performance, Good pressure resistance sealing ability, Low pressure loss measurement tube, High intelligentization, Maintenance-free.


Industry application

Electromagnetic flow meter is a kind of speed meter which has a high accuracy and reliability and is widely used in petroleum, chemical engineering, steel, food, electricity, paper, water treatment, water supply, heat supply, environmental protection and other industries.