Wednesday, September 28, 2016

Selecting the Right Magnetic Level Indicator (MLI)

magnetic level indicator
Magnetic level indicator
(courtesy of Orion Instruments)
The magnetic level indicator (MLI), also called a magnetically coupled liquid level indicator or a magnetic level gauge, is in widespread use throughout the process industries. Originally designed as an alternative to glass sight gauges, MLIs are now commonly used in new construction and plant expansions.

Companies in the process industry need the ability to visually monitor liquid levels in vessels (boilers, storage tanks, processing units, etc.). Traditionally, armored glass sight gauges have been used. However, many companies want an alternative to sight gauges to avoid problems such as breakage, leaks, or bursting at high pressures and extreme temperatures. In addition, the visibility of the sight glass can be poor and often affected by moisture, corrosion, or oxidation.

Magnetic level indicators (MLIs) do not have the shortcomings of glass sight gauges and are suitable for a wide variety of installations.

In an MLI, the magnets within a float and an indicator are magnetically coupled. The float, located inside a chamber, tracks the surface of the liquid. A magnet or magnet assembly inside the float creates a magnetic field, which penetrates the chamber wall to couple with the magnetic field created by the magnets in the indicator flags that display the fluid level.

Please read the following document for a complete understanding in the operation and selection of magnetic level gauges in process applications. For more information on MLI's, or any process level application, call BCE at (510) 274-1990 or visit