Electromagnetic flowmeter​ is a kind of variable area flowmeter. The working principle of electromagnetic flowmeter is that in a vertical cone tube that expands from bottom to top, the gravity of the circular cross-section float is borne by hydrodynamic force, and the float can move in the cone.

GMF400 Insertion electromagnetic flow meter​ is composed of insertion electromagnetic sensor and electromagnetic flow converter, used to measure the conductive liquid that electrical conductivity is greater than 5 us/cm