This principle is used in the electromagnetic flow meter to measure the volume flow rate of the fluid. The flow meter typically consists of two electromagnetic coils that are mounted on opposite sides of a non-magnetic measuring tube. Two electrodes are fitted inside the tube to detect the voltage generated by the conducting fluid. Although these electrodes come into contact with the fluid, they do not obstruct its flow. The inside of the measuring tube is lined by an insulating material such as rubber, neoprene, etc. which is resistant to the properties of the fluid. The flow meter also includes an electronic control unit which calculates the flow rate and displays the output.
When current is applied to the coils, they generate an alternating magnetic field across the cross-sectional area of the tube. A fluid flowing through the magnetic field acts as a conductor, and a voltage is induced. The induced voltage is picked up by the electrodes and sent to a transmitter which is either mounted on the flow meter or connected remotely. The transmitter calculates the volumetric flow rate and displays the output.
Calculation of the volumetric flow rate
The induced voltage is calculated using the following equation: