The various types of moisture meters and their main applications
With the development of scientific research and the progress of production technology, the quantitative analysis of moisture has been listed as one of the basic items in the physical and chemical analysis of various substances, as an important quality index of various substances. According to the different moisture contents in different forms of samples, different requirements for the determination of moisture are put forward. Moisture measurement can be the control of industrial production
Analysis can also be used to sign the quality of industrial and agricultural products; moisture can be measured from tons of products, or moisture can be analyzed in the laboratory with only a few microliters of test solution; it can be a few percent to several percent water content Tens of constant moisture analysis, but also trace moisture analysis with a water content of less than one millionth.
Moisture analysis methods can generally be divided into two categories, namely physical analysis and chemical analysis. Classical moisture analysis methods have been gradually replaced by various moisture analysis methods. The main moisture analyzers currently on the market are Karl Fischer moisture analyzers, infrared moisture meters, dew point moisture meters, microwave moisture meters, and Coulomb moisture meters.
And some special moisture meters. The determination methods of these instruments are easy to operate, high in sensitivity and good in reproducibility, and can measure continuously and display data automatically.
Foreign moisture analyzers have certain advantages in terms of accuracy and stability, but they are expensive, which some domestic laboratories and enterprises cannot afford. In recent years, many domestic instrument manufacturers have strengthened the research and practice of moisture analyzers, and achieved very obvious benefits.
It is close to the international level and can meet the needs of general laboratories and enterprise production.
The Karl Fischer method is a classic method. After being improved in recent years, the accuracy has been greatly improved and the measurement range has been expanded. It has been listed as a standard method for the determination of moisture in many substances. Imported Karl Fischer moisture analyzers that have been active in the domestic market in recent years include France's Raymond, Switzerland's Metrohm, Germany's Mettler-Toledo, Germany's
The infrared moisture meter is easy to operate, less time-consuming, and the measurement result is accurate. Therefore, the infrared moisture meter can be widely used in the experimental analysis and daily purchase control and process detection of chemical, pharmaceutical, food, tobacco, grain and other industries.
The dew point moisture meter is easy to operate, the instrument is not complicated, and the measured results are generally satisfactory. It is often used for the determination of trace moisture in permanent gases. However, this method has a lot of interference, and some easy-to-cool gases, especially when the concentration is high, will condense before water vapor and cause interference.
Coulometric moisture analyzers are commonly used to measure the moisture contained in gases. This method is easy to operate and responds quickly, and is especially suitable for the determination of trace moisture in gas. If it is determined by general chemical methods, it is very difficult. However, the electrolysis method is not suitable for the determination of alkaline substances or conjugated dienes.
The microwave moisture analyzer uses the microwave field to dry the sample, which accelerates the drying process. It has the characteristics of short measurement time, convenient operation, high accuracy, and wide application range. It is suitable for grain, paper, wood, textiles, and chemical products. Determination of moisture in powdery and viscous solid samples, and can also be applied to petroleum,
