Magnetic flap level gauge is a floating ball type metal tube on-site indication level gauge, which has the advantages of high sealing, leakage prevention, and can safely and reliably measure the liquid level under high temperature, high pressure, strong corrosion, and high viscosity conditions. There is no blind spot in the entire measurement process, and the display is eye-catching, the reading is direct, and the measurement range is large. Equipped with liquid level alarm and control switch, upper and lower limit alarm and control of liquid level or boundary can be achieved. Equipped with various transmitters, the signal of liquid level or boundary can be converted into 4-20mA standard signal output, and can be combined with communication protocols such as HART and FOXCOM and fieldbus to achieve remote detection, indication, recording and control.

Magnetic flap level gauges have been widely used in various fields of industrial production, especially in the petrochemical industry. At present, the types of magnetic flap level gauges have been very refined, such as ordinary type, medium temperature and pressure type, high temperature and high pressure type, low temperature type, anti-corrosion type, extremely low density liquid type, food hygiene type, and various types. Some manufacturers even offer more than 30 models, which fully demonstrates that magnetic flap level gauges should be carefully analyzed and studied in their selection and application. The selection of any instrument should take into account the actual working conditions, and the magnetic flap level gauge is no exception. Although the structure and principle of the magnetic flap level gauge are simple, problems may arise if the working conditions are not suitable. For example, liquid level measurement of low-density gasification media such as liquefied gas, methane, and ethane, and liquid level measurement of liquid sulfur. Analyze the application of magnetic flap level gauges in these situations in order to better meet the requirements of production processes.

The principle of the magnetic flap level gauge is very simple and works based on the principles of buoyancy and magnetic coupling. The key components are the magnetic float, magnetic flip column, and sealing of the magnetic flip column section. The magnetic float is related to whether it can achieve high temperature, high pressure, and extremely low density liquid type magnetic flap level gauges; The magnetic flip column is related to whether the following speed is smooth, whether the flip is correct, and whether it can maintain long-term color retention, especially in outdoor environments with long light exposure time. Currently, the magnetic flip column produced by the precision alumina ceramic sintering process on the market is a very good choice; The sealing of the magnetic flip column is crucial to ensuring its normal use.

Low density and easily gasified media include commercial liquefied gas, methane, and ethane. If a conventional magnetic flap level gauge is used, when the temperature is high, a large number of bubbles are generated after the medium evaporates, which impact the magnetic float up and down. The outer magnetic flap column does not follow the speed enough, causing some of the magnetic flap columns to flip and some not to flip. In this way, the flipping and non flipping magnetic flap columns are mixed together, and the specific position of the liquid level cannot be reflected. At the same time, the magnetic float jumping up and down too quickly can easily cause collision and friction between the magnetic float and the measuring chamber, leading to damage or reduced service life of the magnetic float. The direct solution to this problem is to control the degree of vaporization of the medium to ensure that the high temperature outside does not radiate into the medium. Therefore, some people have adopted the principle of insulated bottles, which is to add a vacuum jacket outside the measuring chamber of the magnetic flap level gauge. This approach has a certain effect but is not very ideal. At present, there is a liquefied gas type magnetic flap level gauge, which adopts a dual tube structure. The main conduit of the level gauge is divided into a vaporization chamber and a measurement chamber. When the medium inside the level gauge is affected by temperature and vaporizes internally, bubbles will rise up along the vaporization chamber without entering the measurement chamber and affecting the operation of the magnetic float. Due to the fact that the bubbles generated by the vaporization of the medium, if they can be discharged during the rising process, will not forcefully hit the magnetic float, this structure leaves space for the bubbles generated after the vaporization of the medium to be discharged, allowing the magnetic flap level gauge to work normally even when the medium vaporizes in large quantities.

The application of magnetic flap level gauge in liquid sulfur measurement has always been a difficult point in the chemical industry, as liquid sulfur crystallizes and becomes solid below 100 ° C. Therefore, the selection of instruments must ensure the temperature of liquid sulfur to prevent its solidification. There are currently liquid sulfur type magnetic flap level gauges available on the market for measuring liquid sulfur. The method is to first add a high-temperature steam jacket outside the measuring room and heat the medium with high-temperature steam; Secondly, in order to ensure that the medium liquefies outside the high-temperature jacket, a vacuum jacket is added to prevent the thermal energy of the high-temperature steam from being attenuated, keeping the medium constant within the liquefaction temperature range. The magnetic flap level gauge processed through the above process can smoothly measure the liquid level of liquid sulfur. The upper and lower limit alarms for liquid sulfur are the same as other magnetic flap level gauges, but the liquid level is converted into a 4-20mA standard signal output by combining the liquid sulfur type magnetic flap level gauge with other secondary level instruments, and can be overlaid with communication protocols such as HART and FOX-COM and FF fieldbus to achieve remote detection, indication, recording, and control. In addition to the traditional use of reed switches for remote transmission, it is recommended to use magnetostrictive level transmitters here. The solution is to use the float of the magnetic flap level gauge as a magnetostrictive float, which not only has the function of driving the magnetic flap column, but also serves as a magnetostrictive float. Tie the magnetostrictive waveguide tube outside the measuring chamber of the magnetic flap level gauge, and the magnetic float will generate waveguide distortion pulses while driving the magnetic flap column, so that the magnetostrictive level gauge will also work normally. In this way, magnetostriction does not directly come into contact with the process medium, so there is no need to consider temperature, pressure, and process connections.

The LED magnetic sensitive dual color light column level gauge is very suitable for industries such as steel and chemical industry with large smoke and dust environments and containing fine iron filings. The flip column of this level gauge uses semiconductor LED light-emitting devices, which have the advantages of high brightness, longer visible range of red and green dual color display, clearer scale scale and wider display range. Its daytime observation distance is 60m and nighttime observation distance can reach over 200m. In enterprises containing a large amount of fine iron filings, if traditional magnetic flip level gauges are used, the red and green colors of the magnetic flip column will be covered by the fine iron filings due to magnetic adsorption, making it impossible to observe the liquid level. And the magnetic sensitive LED dual color light column level gauge can effectively solve this problem, because the flip column of the magnetic sensitive LED does not have magnetic conduction. This type of liquid level gauge is very suitable for applications where the light is dim and it is difficult to observe the liquid level up close, with liquid green and gas red visible at a glance.

Magnetic flap level gauges can be used in conjunction with transmitters. Due to the wide application of magnetic flap level gauges in industries such as petrochemicals, their many advantages have been widely recognized. Therefore, in critical situations, some magnetic flap level gauges are now used together with other transmitters, using dual systems for control to ensure the safety of equipment use. Below are some conventional dual system applications discussed. Electric float and magnetic flip column dual system liquid level gauge. The combination of this dual system liquid level gauge adopts dual chamber dual system liquid level measurement, on-site liquid level (boundary) indication measurement, and float remote transmission, which are independent of each other. It is suitable for high temperature, high pressure, small range, and key process liquid level control and interlocking occasions, and has the advantages of high cost-effectiveness, high measurement accuracy, high reliability, and long service life. This dual system is not suitable for working conditions with a large range, such as situations where the range is greater than 3m. Due to the dual system, the weight of the instrument itself is too large, and the connecting flange is prone to damage after being subjected to heavy loads for a long time, so support is needed. At the same time, the float transmitter can achieve a large range that depends on the density of the medium, so beyond this limit, it is impossible to achieve this dual system liquid level measurement.

Magnetic flap level gauge has been widely used and recognized as a level measuring instrument. In addition to the several dual system level gauges mentioned in the article, it can also be combined with dual flange level transmitters and various level transmitters for measuring differential pressure and pressure to be applied in various occasions.