Magnetic Level Indicators (MLIs) and Bridle Combination Units

Magnetic level indicators provide highly visible indication of level with or without signal outputs monitoring tail and vessel level. The term bridle is used to describe a vertical pipe connected to the side of a storage tank or process vessel, most often with side-to-side or side-to-bottom connections. Because the fluid inside the bridle rises and falls equally with the level of fluid inside the tank or vessel, bridles have been adapted for level measurement use on a broad scale.

Below is a good instructional reference document (courtesy of VEGA) on how magnetic level indicators (MLIs) are installed and how they work.

Download the "Magnetic Level Indicators and Bridles for Level Measurement and Visualization" document here.

Magnetic Level Indicators (MLIs) and Bridle Combination Units from Classic Controls, Inc.

Magnetic Liquid Level Gauges in Industrial Settings

Magnetic liquid level gauge combined with
guided wave radar in a single assembly
Vega Americas

Magnetic liquid level gauges are an excellent alternative to sight glass level gauges for many process measurement applications. Their reliable performance and adaptability to process requirements has made them a primary choice in the industrial arena.

Essentially, a magnetic level gauge or magnetic level indicator, is a sight glass with enhancements that provide better readability and a form factor enabling the inclusion of additional level monitoring functions on the same device. Where a sight glass requires operator proximity to read liquid level, the magnetic level gauge's indicating scale, or flags, can be clearly viewed from a considerable distance. A sight glass gauge can also be hindered by difficulties in visually determining liquid level because of deterioration of the glass surface or physical properties of the liquid. Magnetic level gauges remove the need to observe the liquid directly by incorporating a float device within a tube connected to the liquid containing vessel. As the float moves in response to liquid level changes, its magnet causes the indicator flags on the scale to rotate and display either a black face, indicating no liquid present at that position, or a colored face.

Magnetic level indicators or gauges can be modified with a range of options, including armored casings to protect the tube and float arrangement and limit switches to signal attainment of predetermined liquid levels. Combining a magnetic level indicator with another level measurement technology, such as guided wave radar or magnetostrictive, in a single assembly can provide an analog process signal representing continuous liquid level and serve as a redundant measuring device for critical applications.

The document included below provides illustrated detail about the devices and their proper application. There is more detail available, so share your process measurement requirements and challenges with instrumentation experts. The combination of your process knowledge and their product application expertise will produce effective solutions.

Combination magnetic and guided wave radar liquid level indicator from Classic Controls, Inc.

Measurement of Level and Interface with Guided Wave Radar

Guided wave radar application
illustration.

Extreme process conditions such as temperature, pressure or corrosion make selecting the right sensor a real challenge. Maintenance-free instrumentation with a long service life is a requirement for maintaining shutdown intervals of several years without premature production stoppages.

When it comes to measuring level, guided wave radar (GWR) transmitters are suitable for level measurement in liquids and bulk solids. In liquids, they can also detect the interface between two products. They measure liquids reliably, even under high pressure and extreme temperatures. They can be used in simple as well as in aggressive liquids and are suitable for applications with stringent hygiene requirements. The sensors measure light as well as heavy bulk solids with absolute reliability, even in the presence of dust and noise, and without being affected by build-up or condensation. Density fluctuations, steam generation or strong pressure and temperature fluctuations do not influence the measuring result with guided wave radar. Also buildup on the probe or the vessel wall do not influence the measurement.

Guided wave radar
level control
(courtesy of Vega)

Measuring Principle

High-frequency radar pulses are coupled onto a cable (solids) or rod (liquids) and guided along the probe. The pulse is reflected by the product surface. The instrument calculates the level from the running time of the radar pulses and the entered tank height.

Advantages

Guided wave radar sensors operate independently of noise, pressure or temperature fluctuations and are also completely unaffected by changes in density, foaming, steam or dust. Buildup on the probe or on the container wall does not affect the measurement either. This allows simple, straightforward system design and engineering. The menu-driven adjustment routines allow simple, time-saving and confident setup.

For more information on guided wave radar level applications, contact:

For more information, contact:
Classic Controls, Inc.
5095 South Lakeland Drive
Lakeland, Florida 33813
Phone: 863.644.3642
Fax: 863.648.0484
Email: sales@classiccontrols.com
www.classiccontrols.com