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- Moisture Analyzer or Universal Moisture Meter. Characteristics. Types. Purpose and application.
- Determination of the mass fraction of the nitrogen according to Kjeldahl method and the mass fraction of protein
Moisture Analyzer or Universal Moisture Meter. Characteristics. Types. Purpose and application.
The term universal moisture meter assumes that such instrument can be used to analyze virtually any material, i.e. for the analysis of air humidity, solid substances, building materials, wood, food, textiles, and much more. The cost of such devices can reach up to several hundred thousand and even up to a million rubles. However, they are of the greatest interest among all devices called moisture meters/ hygrometers.
So the moisture meter/ hygrometer is a specialized device for measuring the degree of humidity of an object. As a rule the object is a solid object, or a loose consisting of solid particles material. Then, let's try to categorize the moisture meters according to their application. Universal moisture meters and moisture analyzers as well as any other instruments can be divided into portable and laboratory:
- Portable universal moisture meters are miniature devices which are intended for measuring the moisture content of such materials as: construction materials, wood, bulk goods including grains, cereals and less often air mixtures. The operation of these instruments is quite often based on the principle of using multiple remote sensors. So for bulk goods a volume-planar sensor is used, and for analyzing the degree of air humidity - a probe. Alternatively one dielectric sensor can be used; however, the scope of application of such universal devices is sharply reduced.
Most portable devices have a carrying case, as well as the option for connection to a PC.
- Laboratory universal moisture meter/ hygrometer (moisture analyzer) is a stationary instrument that looks like a expensive laboratory scales which in fact is natural. Practically all laboratory instruments have a strain compensation, and operate on the principle of weighing by heating (drying-weight method). In the heating chamber of such moisture meters either a halogen heater (such as in HX204 moisture meter from Mettler Toledo) or infrared (as in the Sartorius MA150 moisture analyzer) can be used.
Universal laboratory moisture meters are able to analyze virtually any substance and material, including bulk/ loose and solid substances, chemical, mineral and organic, food, textiles. As an example, you can give the universal gravimetric moisture meter EVLAS-2M.
Specially we should mention the laboratory device VAD-40M which is intended for the analysis of moisture content in transformer oil and other petroleum products, as well as Kovalev PVK-F moisture densimeter which is intended for the rapid measurement of density, porosity and moisture content of various soils in the field conditions. These devices cannot be classified as universal, but at the same time, because of the principles on which their work is based, they cannot be attributed to any other kind of moisture meter. Methods of operation of universal moisture meters/ hygrometers In general the drying-weight methods for the determination of moisture content used in laboratory moisture meters/ hygrometers are the most accurate. That is why all laboratory moisture meters/ hygrometers work by using this method. However, such methods are most labourious since for the measurement by the drying-weight method since for the measurement by the drying-weight method the use of high-precision scales with a balancing function jointly with a hermetic/ sealed drier with an output is required.
There are also indirect methods for the determination of moisture saturation used in portable moisture analyzers/ hygrometers. They are not so time-consuming and laborious, measurements are produced in real time, and the results obtained are within the limits of permissible errors. Indirect methods include: Conductometric, super high-frequency method, capacitive method, infrared method of the moisture content determination. Moisture meters of this type do not measure moisture directly, but a moisture-related physical parameter (for example, the resistance of a wet material, spectrometric analysis in IR radiation) after which the measured value of such a parameter is transferred to the respective moisture value. Any indirect method requires a preliminary calibration, both in composition and density of the material, and for the compliance with the norms of the relationship between the measured parameter of a given material and humidity. Modern moisture meters/ hydrometers and moisture analyzers have in-built calibration settings for different types of test material.
Thermo gravimetric moisture analyzers, i.e. those that work on the drying-weight method can also have multiple modes of operation allowing a user to select the type of test material, automatic, semi-automatic or time mode, the level of heating, and control other drying parameters. The drying chamber of the drying-weight moisture meter can be equipped with halogen or infrared dryers. The second are the most up-to-date. The principle of operation of the moisture analyzer of this type is to measure the difference in weight between the original product and the product after complete drying.
Application of universal moisture meters/ hygrometers In general the scope of universal moisture meters/ hygrometers is very extensive. Let us consider some of the most frequently used and most rare applications of such devices.
Moisture meters and stationary moisture analyzers are used to control the moisture content of raw materials and/ or finished products, the subject of analysis, thus, can be:
Moisture analyzer is a high-precision instrument. No special knowledge is required for the analysis. Moisture measurement can be carried out even with a small amount of sample. The automation of measurements and the option for connection to a PC make working with these devices simple and convenient for users.
Sibagropribor has been producing and supplying the universal moisture analyzer Evlas-2M for more than 20 years.
For today Evlas 2M is an up-to-date analyzer that includes the best thermogravimetry developments providing high accuracy of measurements and reliability of operation. Evlas-2M is a compact, affordable and highly accurate moisture analyzer that is ideal for quality control of products, as well as for providing input control in the reception departments.
Evlas-2M is a compact, affordable and highly accurate moisture analyzer that is ideal for quality control, as well as to provide input control in the departments of acceptance. The scope of this moisture analyzer: control of moisture content in raw materials, products and semi-finished products of the food and processing industry, chemicals, pharmaceuticals, building materials and other materials. The advantages of the analyzer:
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