What are Electromagnetic Flow Meters?

Electromagnetic flow meters(or magmeters) are a type of velocity or volumetric flow meter that operate pursuant to Faraday’s law of electromagnetic induction – which states that a voltage will be induced when a conductor moves through a magnetic field. Electromagnetic flow meters can detect the flow rate of conductive fluids only. Early magmeter designs required a minimum fluidic conductivity of 1-5 microsiemens per centimeter for their operation. The newer designs have reduced that requirement a hundredfold to between 0.05 and 0.1.

An electromagnetic flowmeter consists of a non-magnetic pipe that is lined with an insulating material. A pair of magnetic coils is situated as shown in Figure 1, and a pair of electrodes penetrates the pipe and its lining.

Improve Accuracy. Decrease System Maintenance. Electromagnetic meters are a leading choice to deliver the performance and precision your applications require.

Minimal Maintenance. Has no moving parts or flow obstructions, which virtually eliminates maintenance and pressure drops.

Impressive Accuracy. Provides accuracy readings up to +0.20% of the measured value.

Wide Turndown Range. Features a wide turndown ratio up to 400:1, providing wide flow range capabilities across a variety of applications.

Measuring Principle

Electromagnetic meters operate under Faraday’s Law of Electromagnetic Induction to measure liquid velocity. The law states that a conductor moving through a magnetic field produces an electrical signal within the conductor, which is directly proportional to the velocity of the water moving through the field.

Features Of An Electromagnetic flow meters

Within the context of the principles listed above, electromagnetic flow meters generally have the following features.

Pros

--Unaffected by the temperature, pressure, density,or viscosity of the liquid.

--Able to detect liquids that include contaminants (solids, air bubbles)

--There is no pressure loss.

--No moving parts (improves reliability)

Cons

--Cannot detect gases and liquids without electrical conductivity.

--A short section of straight pipe is required.