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Cement Producer Uses Guided Wave Radar Level Measurement
By Joe Lewis
Aug 5, 2006 - 10:07:00 AM

Flexar guided wave radar on flyash silo
As part of the cement production process it is commonplace to add flyash in order to improve the material characteristics of the cement. Flyash in the cement industry is the finely divided residue resulting from the combustion of ground or powdered coal, which is transported from the firebox through the boiler by flue gases.

Flyash is a by-product of coal-fired electric generating plants. The flyash used at this cement production facility comes from a nearby power plant and is stored in silos at the plant site. In order to ensure efficient production of the plant, this cement producer needs to know exactly how much flyash they have at any given time.

The cement producer recently added another silo for their flyash storage, increasing the total to two silos. The new silo is about 60ft. (18.3m) high and 21ft. (6.4m) in diameter. The amount of flyash available can impact their production capacity significantly. Recent demand necessitated the additional silo and the producer needed a way to accurately measure the amount of material. The other silo has an aging sonar unit and the producer was keen on moving away from this technology to something that would be accurate and more reliable, even during filling when heavy dust exists within the silo.

A solution was needed and the cement producer chose to work with Monitor Technologies LLC. Flyash is a powder and the internal silo atmosphere during filling is extremely dusty, but Monitor knew the best solution to recommend. After quickly consulting with the cement producer, Monitor Technologies recommended the Flexar™ guided wave radar continuous level sensor.

Flexar is a guided wave radar continuous level sensor based on TDR (time domain reflectometry) technology. Distance/level is measured by the time-of-flight of the reflection of a microwave signal (transmitted down the wave-guide, which is a heavy-duty 0.3” SS cable with 3.9 ton tensile strength) off the material surface. Flyash, like cement, has a relatively low dielectric constant but the Flexar unit has been proven successful on flyash at other facilities so Monitor knew they had the right solution.

Installation and start-up was quick and easy. Monitor’s technical support manager made a courtesy call at the plant within a couple of weeks of installation and the cement producer personnel had done everything perfectly. Even though flyash has a low dielectric constant Flexar’s direct measuring mode was extremely successful in providing real-time continuous updates of the material level during filling and drawdown.

In fact, the cement producer personnel claim the Flexar unit is “excellent” and they couldn’t be happier. In fact, they plan to replace the sonar unit in the old silo with Flexar as soon as they can. Guided wave radar is a great replacement for many technologies in both solids and liquid applications.

For more information on the Flexar guided wave radar product line and other solutions from Monitor Technologies visit www.monitortech.comMonitor





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