Electromagnetic flowmeter working principle and use

working principle

The working principle of electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. In the electromagnetic flowmeter, the conductive medium in the measuring tube corresponds to the conductive metal rod in the Faraday test, and two electromagnetic coils at the upper and lower ends generate a constant magnetic field. When there is a conductive medium flowing, an induced voltage is generated. Two electrodes inside the pipe measure the induced voltage generated. The measuring pipe is electromagnetically isolated from the fluid and the measuring electrode by means of a non-conductive inner lining (rubber, Teflon, etc.).

Structure and use

The flowmeter consists of a primary device and a secondary device. Flowmeters in the form of a combination of a primary device and a secondary device can be divided into split type and integral type; the flowmeter is mainly used to measure the volumetric flow rate of the conductive liquid. (Excerpt: JJG 1033-2007 Electromagnetic Flowmeter Verification Procedures)