A magnetic flow meter, mag meter, or electromagnetic flow meter is a kind of instrument which measures the volume flow rate of the conductive fluid based on the principle of Faraday's Law of Electromagnetic Induction. With a large measurable flow range, the ratio of the maximum flow rate to the minimum flow rate maintains above 20:1. The mag flow meter is suitable for wide range of industrial pipe diameter, and the maximum can reach up to 3m. The output signal and the measured flow are linear, and the magnetic flow meter has high measurement precision. It can effectively measure the flow rate of fluids with a conductivity more than 5μs/cm, such as acid solution, alkaline solution, saline solution, water, sewage, corrosive liquid, mud, ore pulp, and paper pulp. Nevertheless, the electromagnetic flow meter cannot be used to measure the flow of gases, steam and purified water.