An Electromagnetic flow meter (mag flow meter) is a volumetric flow meter which does not have any moving parts and is ideal for wastewater applications or any dirty liquid which is conductive or water based.

A Electomagnetic flow meter will generally not work with hydrocarbons, distilled water, and many non-aqueous solutions.  Magnetic flow meters are also ideal for applications where low-pressure drop and low maintenance are required.

To apply this principle to flow measurement with a Electromagnetic flow meter, it is necessary first to state that the fluid being measured must be electrically conductive for the Faraday principle to apply.

As applied to the design of magnetic flow meters, Faraday’s Law indicates that signal voltage (E) is dependent on the average liquid velocity (V) the magnetic field strength (B) and the length of the conductor (D) (which in this instance is the distance between the electrodes).

Also, In the case of wafer-style electromagnetic flow meter, a magnetic field is established throughout the entire cross-section of the flow tube.  If this magnetic field is considered as the measuring element of the magnetic flow meter, it can be seen that the measuring element is exposed to the hydraulic conditions throughout the entire cross-section of the flow meter.  With insertion-style flow meters, the magnetic field radiates outward from the inserted probe.