Electronics Knowhow

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A moisture analyzer is a device used in the measurement of moisture content. It is used in a variety of applications, to measure samples of many different substances. Moisture analyzers are used in wide variety of different industries such as food processing, pharmaceuticals, construction and chemical preparation.

In some instances, dealing with a little moisture is not a major problem. Moisture in a lab or other controlled environment, however, can be a source of serious difficulty. In some cases, too much moisture can totally destroy a scientific experiment or process.

Many chemicals and mixtures can be compromised by exposure to too much moisture. Many products, both organic and synthetic in nature, can experience strength and integrity degradation when too much moisture is present. A moisture analyzer can be used to measure and monitor moisture content, not only in a laboratory, but also in an extensive range of other applications. Applications that may call for the use moisture analyzers range from determining the freshness of coffee to ascertaining the composition of paint.

Often, these analyzers are small instruments that are designed for ease of use. They are manufactured by many different companies but their designs tend to be very similar. The way in which the moisture analyzers operate is typically similar as well.

When using a moisture analyzer, a sample is usually placed into a small chamber. Inside this chamber, a computer is used to record the weight of the sample. The sample is then heated to evaporate the moisture present in the sample. During the heating process, the sample continues to be weighed periodically. Once the measurement of the sample becomes constant, the user is alerted and evaporation is completed. The analyzer then computes the moisture content of the sample.

The classic laboratory method of determining moisture level in solid or semi-solid materials is called loss on drying (LOD). In this procedure, a sample of material is weighed, heated in an oven, cooled in the dry atmosphere using a desiccant and is then reweighed. Assuming volatile content of the solid is primarily water, this technique provides a good measure of moisture content and can be considered an effective moisture analyzer of a sort.

Because this manual laboratory method is relatively slow, automated moisture analyzers have been developed that can reduce the time necessary for a test from a couple hours to just a few minutes. These analyzers incorporate an electronic balance with a sample tray and a surrounding heating element. Using microprocessor control, the sample can be heated rapidly and a result computed prior to the completion of the process, based on the moisture loss rate, which is known as a drying curve.

A halogen moisture analyzer can be used to measure the moisture content of virtually any substance. The instrument operates on the thermogravimetric principle. A halogen radiator dries the test substance while the precision balance integrated in the instrument continuously measures the sample weight. The total weight loss is interpreted as moisture content. The primary benefit of using a halogen radiator involves a shorter measurement time compared with traditional drying methods. The ring shape of the halogen radiator and its position above the sample, result in exceptionally even heating of the sample and therefore superior repeatability of the measurement result.

The basis for the calculation of the moisture content is the weight loss of the sample at the end of drying. Some moisture analyzerdevices provide final results, intermediate results, procedures as well as method documentation using a built-in printer. These analysis reports and calibration records satisfy the exacting demands of the standard quality systems (GLP, GMP and ISO 9000).