Selection and Application Analysis of Magnetic Column Liquid Level Gauge

Selection and Application Analysis of Magnetic Column Liquid Level Gauge？The magnetic turning column level gauge is a floating-ball type metal tube on-site indicator level gauge. The advantages of the level gauge are high sealing, leak-proof and safe and reliable under high temperature, high pressure, strong corrosion, and high viscosity conditions. Measure the liquid level, there is no blind area in the whole measurement process, the display is eye-catching, the reading is direct, and the measurement range is large. Equipped with liquid level alarm and control switch, it can realize the upper and lower limit alarm and control of liquid level or interface level. Equipped with various transmitters, the signal of liquid level or interface level can be converted into 4-20mA standard signal output, and Can superimpose HART and FOXCOM and other communication protocols and fieldbus to realize remote detection, instruction, recording and control,more details about UHZ-50 magnetic level gauge.
        Magnetic turning column level gauges have been widely used in various fields of industrial production, especially in the petrochemical industry. At present, the types of magnetic turning-column level gauges have been very refined, such as ordinary type, medium temperature and medium pressure type, high temperature and high pressure type, low temperature type, anti-corrosion type, very small density liquid type, food sanitation type and various special types, etc. Some manufacturers have even classified 35 models, which fully shows that the magnetic turning-column level gauge should be carefully analyzed and studied in the selection and application. The choice of any instrument should take the actual working conditions into consideration. The magnetic turning-column level gauge is no exception. Although the structure of the magnetic turning-column level gauge is simple, it will cause problems if the working conditions are not suitable. Such as liquefied gas, methane and ethane and other low-density easily gasified medium level measurement liquid sulfur level measurement and so on. The author analyzes the application of the magnetic column level gauge in these special occasions, so as to better meet the requirements of the production process.
1. Introduction to Magnetic Column Level Gauge
        The principle of the magnetic turning column level gauge is very simple. It works according to the principle of buoyancy and the principle of magnetic coupling. The key components are the magnetic float, the magnetic turning column and the sealing of the magnetic turning column part. The magnetic float is related to whether it can be a high temperature, high pressure and very small density liquid type magnetic turning column level gauge; the magnetic turning column is related to whether the following speed is smooth, whether the turning is correct, and whether it can maintain long-term color, especially in outdoor lighting For long-term occasions, the magnetic flipping column produced by the precision alumina ceramic sintering process on the market is a very good choice; the sealing of the magnetic flipping column part is the key to ensuring the normal use of the flipping column.
2. Instrument selection for low-density and easy-to-gasify media
        Low-density and easy-to-vaporize media include: commercial liquefied gas, methane and ethane, etc. If you use a conventional magnetic flipping level gauge, when the temperature is high, a large number of bubbles will be generated after the medium vaporizes. The bubbles will impact the magnetic float and jump up and down, and the outside magnetic flipping column will not follow the speed enough, which will cause some of the magnetic flipping column to flip and some not to flip. In this way, if the flipped and non- flipped magnetic flipping columns are mixed together, the specific position of the liquid level cannot be reflected. At the same time, the magnetic float will jump up and down too fast, which will easily cause the collision and friction between the magnetic float and the measuring chamber, which will cause the magnetic float to be easily damaged or reduce its value. Service life.
        The most direct way to solve this problem is to control the degree of vaporization of the medium to ensure that the outside high temperature cannot radiate into the medium. Therefore, someone adopted the thermos principle, which is to add a vacuum jacket outside the measuring chamber of the magnetic turning column level gauge. This has a certain effect, but it is not very ideal. At present, there is a kind of special magnetic turning column level gauge for liquefied gas. Its principle is to adopt a double-tube structure. The inner cavity of the main duct of the level gauge is divided into a vaporization chamber and a measurement chamber. When bubbles are generated, the bubbles will rise up along the vaporization chamber, and will not enter the measurement chamber and affect the operation of the magnetic float. Since the vaporized bubbles of the medium can be discharged during the ascending process, they will not hardly support the magnetic float. This structure leaves room for the bubbles generated after the medium is vaporized, so that the magnetic turning column level gauge vaporizes a large amount of the medium. It can also work normally.
3. Application of magnetic turning column level gauge in liquid sulfur measurement
        Level measurement of liquid sulfur has always been a difficult point in the chemical industry, because liquid sulfur crystallizes and becomes solid when it is below 100°C. Therefore, the selection of the instrument must ensure the temperature of the liquid sulfur to prevent it from solidifying. Currently, there is a special magnetic flip-column level gauge for measuring liquid sulfur on the market. The method is: first add a high-temperature steam jacket outside the measuring room, and pass high-temperature steam to heat the medium; secondly, to ensure that the medium is liquefied in the high-temperature jacket A vacuum jacket is added to the outside to prevent the thermal energy of the high-temperature steam from attenuating and keep the medium within the liquefaction temperature range. The level measurement of liquid sulfur can be carried out smoothly by the magnetic turning column level gauge processed by the above process.
        The upper and lower limit alarms for liquid sulfur are the same as other magnetic turning-column level gauges, but the liquid sulfur special-purpose magnetic turning-column level gauge is equipped with other secondary level meters to convert the liquid level into a 4-20mA standard signal output. It can also superimpose communication protocols such as HART and FOX-COM and FF fieldbus to realize remote detection, instruction, recording and control. It is recommended to use a magnetostrictive liquid level transmitter in addition to the traditional reed switch remote transmission. The solution is to use the float of the magnetic turning column level gauge as a magnetostrictive float. In addition to the function of driving the magnetic turning column, it also has the function of acting as a magnetostrictive float. Tie the magnetostrictive waveguide to the outside of the measuring chamber of the magnetic turning column level gauge. The magnetic float will also generate waveguide twisting pulses while driving the magnetic turning column, so that the magnetostrictive level gauge will work normally. In this way, the magnetostriction is not in direct contact with the process medium, so there is no need to consider the temperature, pressure and process connection.
4. Application of magnetic-sensitive LED two-color light column level gauge
         The LED magnetic-sensitive two-color light column level gauge is very suitable for the steel and chemical industries with large smoke and dust environments and containing fine iron filings. The turning column of the level gauge uses semiconductor LED light-emitting devices, with high brightness, red and green dual-color display visual distance It has the advantages of farther, clearer scale and wider display range, and its observation distance during the day is 60m, and the observation distance at night can reach more than 200m.
         In an enterprise containing a large amount of fine iron filings, if a traditional magnetic turning column level gauge is used, the fine iron filings will cover the red and green colors of the magnetic turning column due to magnetic adsorption, and the liquid level cannot be observed. The magnetic-sensitive LED two-color light column level gauge can effectively solve this problem, because the magnetic-sensitive LED's turning column has no magnetic conduction. This kind of liquid level gauge is very suitable for applications where the light is dark and it is difficult to observe the liquid level from close range. The liquid green and gas red are clear at a glance.
5. Application of magnetic turning column level gauge with other transmitters
          Due to the wide application of magnetic turning-column level gauges in petrochemical and other industries, its many advantages have been widely recognized. Therefore, magnetic turning-column level gauges are now used in combination with other transmitters in key occasions, and dual systems are used for control. Ensure the safe use of equipment. Some conventional dual-system applications are discussed below. Electric float & magnetic turning column dual system level gauge. The combination of this kind of dual-system level gauge adopts dual-cavity dual-system liquid level measurement, on-site liquid level (boundary level) indication measurement and float remote transmission, independent of each other, suitable for high temperature, high pressure, small range and The key process liquid level control and interlocking occasions have the advantages of high cost performance, high measurement accuracy, high reliability and long service life. This dual system is not suitable for working conditions with a large range, such as occasions with a range greater than 3m. Because the dual system causes the weight of the instrument itself to be too large, the process connection flange is easy to be damaged after long-term heavy weight, so it needs to be supported. At the same time, the maximum range of the float transmitter can be determined according to the density of the medium), so this dual-system liquid level measurement cannot be achieved beyond this limit.
        Guided wave radar and magnetic turning column dual system level gauge. The combination of this kind of dual-system level gauge adopts dual-cavity (compound cavity can also be used) dual-system level measurement. On-site level indicator measurement and guided wave radar level gauge remote transmission are independent of each other, which is suitable for high temperature, Low temperature, ultra-low temperature, high pressure and large range, etc. liquid level on-site indication and DCS system interlocking occasions. Because the guided wave radar signal propagates through the probe instead of the air, the output is stable and high in accuracy. The condensed water on the probe will not affect the measurement performance. The measurement is not affected by the state of the medium density, boiling, fluctuation, turbulence or even the mixer blades. The measurement data has nothing to do with the changes of the process temperature, process pressure, and medium density. The liquid can be quickly tracked. Noodles.Magnetostrictive & magnetic turning column dual system level gauge. The combined structure of this kind of dual system is more convenient and practical. In the measurement of liquid sulfur, there has been a simple discussion of this method. The range of this kind of dual system can be made larger and wider.
        The magnetic turning column level gauge has been a widely used and widely recognized level measuring instrument. In addition to the several dual-system level gauges described in the text, it can also be used with double-flange level transmitters and various measurement differences. The combination of pressure and pressure level transmitter is applied to various occasions.