Cement Americas

SPR 2018

Cement Americas provides comprehensive coverage of the North and South American cement markets from raw material extraction to delivery and tranportation to end user.

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www.cementamericas.com • Spring 2018 • CEMENT AMERICAS 31 FEATURE must be modified each time a new ship- ment of the product is introduced. Another benefit of frequent moisture measurement is for products sold based on regulated moisture content. Prescribed percentages must be met in order to comply with these speci- fications. In certain industries, heavy fines could be levied, while in others, the product or substance will not be accepted by the regulating agen- cy. These industries include gypsum and pharmaceutical manufacturers, among others. There may even be legal ramifications, if the acceptable moisture content of a product is decided prior to pur- chase or shipping. Fees can be levied on companies that do not ship at the agreed moisture level or the product could be rejected outright. Finally, since moisture content con- tributes significantly to the weight of such materials, properly drying a sub- stance to acceptable limits before it is transported can dramatically reduce shipping and disposal costs. Simplifying Moisture Measurement Although traditional laboratory and online based moisture measurement techniques are useful in the right set- tings, they have lacked the simplicity and flexibility required for frequent spot checks. One common test is Loss on Drying, which measures the total material weight change after drying. However, such tests typically require a sample to be prepared and brought back to the lab. The test takes from 15 minutes to several hours to perform, which is too slow when more immediate measure- ments are required. It also requires the sample to be altered or destroyed. As a result, secondary test methods have been used to deliver faster results. This type of test uses an indirect meth- od and a single conversion to achieve accurate results. Secondary measure- ment techniques are routinely accepted as equal to the gold standard method. Examples are speedometers, common infrared and liquid thermometers and most pressure gauges. If there is a dis- advantage, it is that the instrument must first be calibrated to ensure accu- rate results. In some cases, calibration could only be performed by trained staff familiar with the equipment. In response, industry innovators have developed a simplified approach that allows even less-trained personnel to take portable, instant moisture read- ings of powdered bulk product. T h e a p p ro a c h i nvo l ve s m o i st u re meters that utilize Near-Infrared (NIR) light, a highly accurate, non-contact secondary measurement method that can deliver immediate, laboratory quality moisture readings. "NIR moisture meters allow very accu- rate instant measurement of solids and liquids without contact or sample preparation, so there is no contamina- tion in handheld and online models," said John Bogart, managing director of Kett US, a manufacturer of a full range of moisture and organic com- position analyzers. "Once the meter has been calibrated against the lab or production standard, the calibration is stored in the device so no calibration is required in the field. Measurements are fully traceable to the original mea- surement method." In addition, because the process is non-destructive, samples remain unal- tered so they can be used for addition- al tests or put back into the product stream. "NIR moisture meters follow the prin- ciple that water absorbs certain wave- lengths of light," said Bogart. " The meter reflects light off the sample, measures how much light has been absorbed, and the result is automat- ically converted into a moisture con- tent reading." Unlike complex laboratory equipment, portable NIR equipment is designed for ease of use. For example, with Kett's KJT130 Handheld Portable Instant Moisture Meter, the user simply points the instrument at the product and the moisture content is instantly shown on a digital display, with results accurate to .01 percent in a 0 to 100 percent measurement range. Because no direct contact or sample alteration is required, particle size variation and unusual textures are not an issue. This can be important when used with a range of powder and bulk solid materials in different settings. For ease of use, the unit is operated via user-friendly menu commands. The unit, which is the size of a camcorder, is designed for frequent spot checks wherever necessary, on both station- ary and moving (process line) products. Moisture measurement data may be stored in the instrument, downloaded continuously, or manually recorded. "The goal is for any staff member to be able to successfully use the mois- ture meter wherever it is needed, with minimal required training," said Boga- rt. "This allows powder and bulk solid processors to have the certainty that what they are producing is of the high- est quality. "The key is to cost-effectively be able to conduct as much testing as required, with full confidence in the results, each and every time," added Bogart. For more information, call 800-438- 5388; email support@kett.com; or visit www.kett.com. Del Williams is a technical writer based in Torrance, Calif. Handheld devices are now available that allow even less-skilled personnel to take lab-quality moisture measure- ments.

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