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How Magnetic Level Indicators Work - TechStar

Posted by TechStar on Sep 19, 2022 12:55:48 AM

Many major industrial facilities throughout the world rely upon magnetic level indicators (MLI) to effectively, reliably, and safely visualize and control levels in complex process applications. When safety and performance are at stake, it is critical that manufacturers have the right equipment and understand how to optimize the use of tools. 

Some common questions when choosing a Magnetic Level Indicator:

  • What is a magnetic level indicator?
  •  How do magnetic level indicators work? 
  • What are the benefits of using a magnetic level indicator? 

Continue reading to learn everything you need to know about magnetic level indicators. 

What is a magnetic level indicator?

A magnetic level indicator sometimes referred to as MLI, is a simple, rugged instrument designed to indicate level or interface measurements. The magnetic level indicator indicates the level by using a float magnetically coupled to a column of rotating flaps (flags).   A magnetic level indicator is often used in applications where a sight glass (or glass sight gauge) is not appropriate or underperforming for process variables or plant requirements.

 Magnetic Level Indicators provide accuracy and reliability for commercial and industrial applications in many industries and settings, including:

  • Energy and power plant technology
  • Feed water heaters and boilers 
  • Oil and gas industries
  • Offshore exploration and drilling
  • Pipeline compressor applications
  • Pulp and paper production
  • Food and beverage industry
  • Gas plants
  • Pharmaceutical industries
  • Water and wastewater management

How does a magnetic level indicator work?

A magnetic level indicator relies upon the interaction between magnets inside and outside the fluid chamber to provide continuous level information that is virtually maintenance-free. When a magnetic level indicator is installed on a vessel filled with fluid, it shares the same fluid and level as the vessel. The indicator attaches to the vessel and connects directly to the fluid through a float with a magnet assembly that rests on the surface of the fluid, inside the chamber. As the fluid level in the vessel rises or falls, the float moves too and prompts the magnet assembly to rotate a series of bi-color magnetic flags or flaps that change the visual indicators mounted outside the vessel. 

Benefits of Using a Magnetic Level Indicator

A magnetic level indicator consists of three major components, chamber, float, and indicator system.  The magnetic float is contained within the chamber and tracks the surface of the fluid as the level rises and falls.  The chamber is mounted on the outside of a vessel. The fluid inside the vessel is shared within the chamber that carries the magnetic float and indicating system.  With the magnetic float resting on the surface of the fluid, inside the chamber, as the fluid level within the vessel rises or falls, the float moves and actuates the indicting system which rotates a series of bi-color magnetic flags or flaps that change the visual indicator mounted on the chamber. 

Improve Safety

A magnetic level indicator is made of strong metal and the indicators, transmitters, and switches are mounted to the outside of the device so that they are not affected by the characteristics of the process fluid. A MLI improves safety by reducing the chance of breakage, which is especially critical when process fluids are under extreme pressure or temperature. 

Increase Visibility

A magnetic level indicator is made of strong metal and the indicators, transmitters, and switches are mounted externally which prevents any effects by the characteristics of the process fluid. A MLI improves safety by reducing the chance of breakage, which is especially critical when process fluids are under extreme pressure or temperature. 

Reduce Maintenance

Once a magnetic level indicator is installed, it is virtually maintenance-free. The indicator does not come in contact with the process fluid so there is not a risk of corrosion, build-up, or scaling. 

Eliminate the Need for Power

A magnetic level indicator relies upon magnets to conduct the measurements and change the visuals on the indicator. Magnets do not need a power source to interact with one another, making magnetic level indicators completely autonomous from power sources. 

How to Choose the Right Magnetic Level Indicator

There are different styles of magnetic level indicators. Magnetic level indicators vary in size, number of chambers, and durability standards. It is important to keep in mind that the addition of switches and transmitters can offer alarm points and level control functions. Let’s take a look at three of the top magnetic level indicators on the market. 

Atlas™Magnetic Level Indicator

The AtlasTM is a high-performance magnetic level indicator with a single-chamber design and offers 2″, 2.5″, or 3″ chamber diameters, as required by the application.

Gemini™Magnetic Level Indicator

The Gemini MLI offers innovative level measurement in a special twin-chamber design.  A magnetic float and high-visibility indicator in the primary chamber operate independently of the Guided Wave Radar transmitter in the secondary chamber.

Vector™ Magnetic Level Indicator

Vector is a rugged, reliable and cost-effective Magnetic Level Indicator (MLI). Suitable for a variety of installations, Vector is precision-engineered and manufactured to ensure a long service life.

Contact TechStar today and speak with an expert about your magnetic level indicator applications.  TechStar is your manufacturing representative for instrumentation, automation, and analytical products, including service and training too.

Topics: MLI

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