With the development of scientific research and the advancement of production technology, the quantitative analysis of moisture has been listed as one of the basic items for physical and chemical analysis of various substances, and it is an important quality indicator of various substances. Different requirements for the determination of moisture were proposed according to the different moisture contents in the different types of samples. The determination of moisture can be the control analysis of industrial production, or the quality inspection of industrial and agricultural products; the moisture can be measured from the product of tons; the moisture analysis can be performed with only a few microliters of the test solution in the laboratory; it can be the moisture content. A constant moisture analysis of several to several tens of percent, or a trace moisture analysis with a moisture content of only one millionth or less.
Water analysis methods can generally be divided into two major categories, namely physical analysis and chemical analysis. Classical moisture analysis methods have been gradually replaced by various moisture analysis methods. Currently, the main moisture analyzer on the market is the Karl Fischer moisture analyzer:
Karl Fischer referred to the Fischer method, which is the volumetric separation method for measuring moisture content proposed by Karl Fischer in 1935. The Fischer method is the most specific and correct method for water in various types of chemical methods for measuring the moisture content of a substance. Although it is a classical method, it has been improved in recent years, improved its accuracy, and expanded the measurement range. It has been listed as a standard method for moisture determination in many substances.
The Fischer-Tropsch method is an iodometric method. The basic principle is that when oxidizing sulfur dioxide with iodine, the need for quantitative water to participate in the reaction:
12 Ten S02 Ten 2H2O=2HI Ten H2SO4
The above reaction is reversible. In order to move the reaction in the positive direction and quantitatively proceed, an alkaline substance must be added. Experiments confirmed that pyridine is the most suitable reagent, while pyridine also has the effect of combining with iodine and sulfur dioxide to reduce the vapor pressure of both. Therefore, the reagent must be added to methanol or another solvent containing a reactive OH group to convert the pyridine anhydride pyridine to a stable methyl bisulfate.
Infrared moisture meter:
Infrared heating mechanism: Absorption, reflection, and transmission occur when far-infrared radiation is radiated to an object. However, not all molecules can absorb far-infrared radiation, and only those polar molecules that show electricity can work. Water, organic substances, and high molecular substances have a strong ability to absorb far-infrared rays. When these substances absorb the far-infrared radiation energy and make its molecules, the frequency of natural vibration and rotation of the atom coincide with the frequency of far-infrared radiation, the resonance or rotation of the molecules and atoms easily occurs, and the movement is greatly aggravated and converted into The heat energy raises the temperature inside, so that the substance is quickly softened or dried.
The general heating method is the use of heat conduction and convection, the need to spread through the media, slow speed, high energy consumption, and far-infrared heating is the use of heat radiation, without media transmission. At the same time, since the radiant energy is proportional to the fourth power of the heating element, it not only saves energy, but also has high speed and high efficiency. In addition, far-infrared rays have a certain penetrating power, because the heated and dried substance absorbs far-infrared radiation energy at a certain depth inside and surface molecules, and generates a self-heating effect, so that the solvent or water molecules evaporate, and the heat is even, thereby avoiding Deformation and qualitative change caused by different degrees of thermal expansion, so that the appearance of the material, physical and mechanical properties, fastness and luster, etc. remain intact.
Infrared moisture analyzer is mainly determined by infrared radiation heater and electronic balance to its accuracy and stability.
(Infrared radiation heater: tungsten wire vacuum tube can radiate near-infrared rays, silicon carbide is a long-wavelength far-infrared radiation heater, quartz glass and ceramic infrared heaters can radiate mid-infrared rays)
Infrared Moisture Analyzer The "dry reduction method" of the well-known standard measurement method of the moisture measurement standard is very similar to an infrared moisture meter of heat drying and mass measurement. The "dry reduction method" of the well-known standard method is also called (105°C • 5 hours method), (135°C • 3 hours method), etc., and it is heated for a long time by placing the sample in the dryer. Drying was used to accurately determine the mass change before and after drying, and the amount of water was calculated. For this reason, it is necessary to determine that the staff is very proficient in equipment and technology. Since it takes a long time for the measurement, it is difficult to quickly measure a large number of samples. Therefore, for high accuracy measurement of a wide variety of samples, it is not necessary to use an infrared moisture meter. Although there are some other electrical and optical measurement methods, they are all special instruments that limit the measurement object. In terms of versatility, they are far less than infrared moisture meters.
Scope of application: It can measure food-related articles such as cereals, starch, flour, dried noodles, brewed goods, seafood, fish processed products, processed meat products, seasonings, noodles, hearts, dairy products, dried foods, vegetable oils, etc. , ore sand, coke, glass raw materials, cement, chemical fertilizers, paper, pulp, cotton, all kinds of fiber and other industrial products.
Dew point moisture meter:
The dew point moisture analyzer is easy to operate and the instrument is not complicated. The measured results are generally satisfying and are often used to determine the trace moisture in permanent gas. However, this method interferes more. Some cold-changeable gases, especially at higher concentrations, interfere with condensation than water vapor.
Microwave moisture meter:
The microwave moisture analyzer uses a microwave field to dry the sample to accelerate 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, textile and chemical products, etc. The determination of moisture in powdered and viscous solid samples can also be applied to the determination of moisture in petroleum, kerosene and other liquid samples.
Coulomb moisture meter:
Coulomb moisture meters are often used to determine the moisture content of gases. This method is easy to operate, responds quickly, and is particularly suitable for the determination of trace moisture in gases. If it is measured by ordinary chemical methods, it is very difficult. However, electrolytic methods are not suitable for the determination of alkaline substances or conjugated diolefins.
And some special moisture meters:
These instrument determination methods are easy to operate, sensitive, and reproducible, and can be continuously measured and automatically displayed.
Water analysis methods can generally be divided into two major categories, namely physical analysis and chemical analysis. Classical moisture analysis methods have been gradually replaced by various moisture analysis methods. Currently, the main moisture analyzer on the market is the Karl Fischer moisture analyzer:
Karl Fischer referred to the Fischer method, which is the volumetric separation method for measuring moisture content proposed by Karl Fischer in 1935. The Fischer method is the most specific and correct method for water in various types of chemical methods for measuring the moisture content of a substance. Although it is a classical method, it has been improved in recent years, improved its accuracy, and expanded the measurement range. It has been listed as a standard method for moisture determination in many substances.
The Fischer-Tropsch method is an iodometric method. The basic principle is that when oxidizing sulfur dioxide with iodine, the need for quantitative water to participate in the reaction:
12 Ten S02 Ten 2H2O=2HI Ten H2SO4
The above reaction is reversible. In order to move the reaction in the positive direction and quantitatively proceed, an alkaline substance must be added. Experiments confirmed that pyridine is the most suitable reagent, while pyridine also has the effect of combining with iodine and sulfur dioxide to reduce the vapor pressure of both. Therefore, the reagent must be added to methanol or another solvent containing a reactive OH group to convert the pyridine anhydride pyridine to a stable methyl bisulfate.
Infrared moisture meter:
Infrared heating mechanism: Absorption, reflection, and transmission occur when far-infrared radiation is radiated to an object. However, not all molecules can absorb far-infrared radiation, and only those polar molecules that show electricity can work. Water, organic substances, and high molecular substances have a strong ability to absorb far-infrared rays. When these substances absorb the far-infrared radiation energy and make its molecules, the frequency of natural vibration and rotation of the atom coincide with the frequency of far-infrared radiation, the resonance or rotation of the molecules and atoms easily occurs, and the movement is greatly aggravated and converted into The heat energy raises the temperature inside, so that the substance is quickly softened or dried.
The general heating method is the use of heat conduction and convection, the need to spread through the media, slow speed, high energy consumption, and far-infrared heating is the use of heat radiation, without media transmission. At the same time, since the radiant energy is proportional to the fourth power of the heating element, it not only saves energy, but also has high speed and high efficiency. In addition, far-infrared rays have a certain penetrating power, because the heated and dried substance absorbs far-infrared radiation energy at a certain depth inside and surface molecules, and generates a self-heating effect, so that the solvent or water molecules evaporate, and the heat is even, thereby avoiding Deformation and qualitative change caused by different degrees of thermal expansion, so that the appearance of the material, physical and mechanical properties, fastness and luster, etc. remain intact.
Infrared moisture analyzer is mainly determined by infrared radiation heater and electronic balance to its accuracy and stability.
(Infrared radiation heater: tungsten wire vacuum tube can radiate near-infrared rays, silicon carbide is a long-wavelength far-infrared radiation heater, quartz glass and ceramic infrared heaters can radiate mid-infrared rays)
Infrared Moisture Analyzer The "dry reduction method" of the well-known standard measurement method of the moisture measurement standard is very similar to an infrared moisture meter of heat drying and mass measurement. The "dry reduction method" of the well-known standard method is also called (105°C • 5 hours method), (135°C • 3 hours method), etc., and it is heated for a long time by placing the sample in the dryer. Drying was used to accurately determine the mass change before and after drying, and the amount of water was calculated. For this reason, it is necessary to determine that the staff is very proficient in equipment and technology. Since it takes a long time for the measurement, it is difficult to quickly measure a large number of samples. Therefore, for high accuracy measurement of a wide variety of samples, it is not necessary to use an infrared moisture meter. Although there are some other electrical and optical measurement methods, they are all special instruments that limit the measurement object. In terms of versatility, they are far less than infrared moisture meters.
Scope of application: It can measure food-related articles such as cereals, starch, flour, dried noodles, brewed goods, seafood, fish processed products, processed meat products, seasonings, noodles, hearts, dairy products, dried foods, vegetable oils, etc. , ore sand, coke, glass raw materials, cement, chemical fertilizers, paper, pulp, cotton, all kinds of fiber and other industrial products.
Dew point moisture meter:
The dew point moisture analyzer is easy to operate and the instrument is not complicated. The measured results are generally satisfying and are often used to determine the trace moisture in permanent gas. However, this method interferes more. Some cold-changeable gases, especially at higher concentrations, interfere with condensation than water vapor.
Microwave moisture meter:
The microwave moisture analyzer uses a microwave field to dry the sample to accelerate 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, textile and chemical products, etc. The determination of moisture in powdered and viscous solid samples can also be applied to the determination of moisture in petroleum, kerosene and other liquid samples.
Coulomb moisture meter:
Coulomb moisture meters are often used to determine the moisture content of gases. This method is easy to operate, responds quickly, and is particularly suitable for the determination of trace moisture in gases. If it is measured by ordinary chemical methods, it is very difficult. However, electrolytic methods are not suitable for the determination of alkaline substances or conjugated diolefins.
And some special moisture meters:
These instrument determination methods are easy to operate, sensitive, and reproducible, and can be continuously measured and automatically displayed.
The machine consists of hopper, vibration chamber and coupling and motor. There are eccentric wheel, rubber shaft parts, main shaft bearing and so on. The adjustable eccentric weight can drive to the central line of main shaft through motor. Under the unstable state, it produces centrifugal force that makes raw material from vortex in the sieve. The size of eccentric weight can be regulated in accordance with the different raw materials. The Sieve Machine is suitable for flow operation , it is an ideal equipment for granule which the size proportion is not uniform to separate. It has centrifugal vibration separated layer sieve which is very practical.
Sieve Machine
Sieve Machine,Sieve Shaker,Sieve Shaker Machine,Industrial Sieve
Changzhou Jiafa Granulating Drying Equipment Co.,Ltd , http://www.jf-drying.com