ZERO100E Electromagnetic flowmeters are sensitive devices used to measure the flow of a liquid. Flowmeters use the principles of Faraday’s Law of Induction to calculate the flow.
Sometimes referred to as magmeters, the change in the magnetic field is measured over time, and there is an electrical field perpendicular to the changing magnetic field. This means when a liquid passes through the magnetic field of the electromagnetic flowmeter, an electrical voltage is generated. The voltage is perpendicular to the volume of flow rate. The only way this principle works is if the fluid in question is indeed conductive. Salt water, for example, is a great example of a conductive fluid.
When talking electromagnetic flow meters, there are two basic kinds. Flow-through meters are tubes in the piping system. This is a preferred type because the meter does not impede the flow of the fluid. The meter reads an average velocity of the fluid across two electrodes placed at opposite sides of the pipe.
The second basic kind of electromagnetic flow meter is the insertion style. A probe is inserted into the pipe. This model allows for quick and easy installation and removal. Everything to conduct the measurement is contained in the probe – the magnetic coils and electrodes. A field is generated around the probe tip. The flow is measured at the flow tip, and this is a drawback to the meter style.
The advantages of electromagnetic flow meters are numerous. Both models have advantages and disadvantages, and both are superior to many other flow sensing instrumentation. Fluid properties can change in density and viscosity, so the lack of moving parts of electromagnetic flow meters mean more precise measurements when changes occur. The lack of moving parts also mean there is no parts to wear out and jam, and this leads to less maintenance as a general rule.