Electromagnetic Flow Meter: Advantages and Disadvantages

This page covers the advantages and disadvantages of Electromagnetic Flow Meters, along with a basic overview. It highlights the benefits and drawbacks of using these flow meters.

What is an Electromagnetic Flow Meter?

This type of flow meter operates based on Faraday’s Law of Electromagnetic Induction. Inside the meter, a pair of coils generates a magnetic field. Let’s delve into how an electromagnetic flow meter works.

When a conductive liquid passes through this electromagnetic (EM) field, an electric voltage is induced within the liquid. This induced voltage is directly proportional to the liquid’s velocity. Furthermore, the induced voltage is perpendicular to both the direction of the liquid flow and the direction of the EM field, as described by Fleming’s right-hand rule.

The induced voltage remains unaffected by the liquid’s physical properties, such as temperature, viscosity, pressure, density, and conductivity.

For accurate measurements, the pipe must be completely filled with the liquid. Moreover, the liquid’s electrical conductivity should be at least 5 micro Siemens per cm.

Typically, two main types of electromagnetic flow meters are available:

• Flange Type Electromagnetic Flow Meter: This flow meter is installed directly into a straight pipeline, requiring appropriate plumbing. A relatively short straight pipe section is sufficient for installation. These flow meters come in two variations:
  • Integral Type: The converter is integrated directly with the flow meter body.
  • Remote Type: The measuring sensor unit is installed on the water pipe, while the converter is placed at a separate location and connected via wires.
• Insertion Type Electromagnetic Flow Meter: Suitable for large diameter pipes, these flow meters are used where water supply cannot be interrupted, even for short periods. They require minimal plumbing. The sensor can be installed by inserting the meter between two pipe flanges without removing the measuring pipe.

Benefits or Advantages of Electromagnetic Flow Meter

The following are the key benefits of using an Electromagnetic Flow Meter:

• It has no moving parts, making it less susceptible to disturbances in flow caused by viscosity or density changes.
• The EM flow meter does not obstruct the flow, making it suitable for clean, sanitary, dirty, corrosive, and abrasive liquids.
• Measurements are not affected by the state of flow, whether laminar or turbulent.
• Primarily used for measuring volume flow, it can also measure the temperature, viscosity, density, and electrical conductivity of the medium.
• Electromagnetic flow meters offer superior performance and reliability.

Drawbacks or Disadvantages of Electromagnetic Flow Meter

Here are the drawbacks of using an Electromagnetic Flow Meter:

• Requires a power supply to operate.
• Electronic components are more vulnerable to damage.
• Repairing EM flow meters requires specialized equipment and skilled technicians, increasing maintenance costs.