How Do Magnetic Flow Meters Work?

Sensing pressure may not be hard to understand, but knowing how liquid flows through a medium can be complex because it has to do with flow rates and specific laws of physics. In fact, equipment like the Rosemount magnetic flow meter is only possible through years of discovery and experimentation. Let’s take a closer look at the main principles behind electromagnetic or mag flow meters, to get a better understanding of how they work.

It Starts with Faraday’s Law and Electromagnetic Energy

Without an understanding of Faraday’s Law, many important tools we use today would not be possible. This includes electric motors, transformers, generators and Rosemount magnetic flow meter applications.

Michael Farady was a British physicist who discovered that a magnetic field and conductor could induce an electric circuit. This important relationship between magnetism and electricity has helped us understand basic principles of electromagnetism. Here is what happened in the early part of the Nineteenth Century.

Faraday placed a magnet inside a coil of wire and connected a galvanometer to the coil. He noticed an electric current was produced. However, he quickly realized the magnet had to be in motion to produce a current. When it was idle, the meter did not move. Yet, if the magnet remained motionless and the coil was moved, current was also induced.

Faraday discovered whenever there was relative motion between a conductor and magnet, it created electricity. But how does this affect applications like the Rosemount magnetic flow meter?

Flow meters take advantage of Faraday’s Law and it really is quite simple. By inducing a magnetic field for liquid to flow through, voltage is created and electrodes pick up this voltage and send it to a voltage sensing meter. The faster the liquid is flowing, the more electric current is generated. However, the liquid must be conductive and cannot be something like sterile water.

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