Electromagnetic flow meters are volumetric flow meters that measure the voltage created when conductive liquids move through a magnetic field. According to Faraday's Law, the voltage induced across any conductor as it moves at right angles through a magnetic field is proportional to the velocity of that conductor. With magmeters, the liquid serves as the conductor and the magnetic field is created by energized coils outside the flow tube. Electrodes detect the voltage which is directly proportional to the flow rate.

Electromagnetic flow meters can measure corrosive liquids and slurries, and have the ability to measure flow in both directions with equal accuracy. A conducting fluid and a non-conducting pipe liner are required. Magmeters will generally not work with hydrocarbons, distilled water and many non-aqueous solutions. They are also ideal for applications where low pressure drop and low maintenance are required.

Selecting a Flow Meter

The basis of good flow meter selection is a clear understanding of the requirements of the particular application. Therefore, time should be invested in fully evaluating the nature of the process fluid and of the overall installation.

  1. What is the fluid being measured by the flow meter(s) (air, water, etc…)?
  2. Do you require rate measurement and/or totalization from the flow meter?
  3. If the liquid is not water, what viscosity is the liquid?
  4. Is the fluid clean?
  5. Do you require a local display on the flow meter or do you need an electronic signal output?
  6. What is the minimum and maximum flow rate for the flow meter?
  7. What is the minimum and maximum process pressure?
  8. What is the minimum and maximum process temperature?
  9. Is the fluid chemically compatible with the flow meter wetted parts?
  10. If this is a process application, what is the size of the pipe?

If you have any questions or need any help selecting a flow meter, please contact us at sales@instrumart.com or 1-800-884-4967 to speak with an applications engineer.