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As the \"vessels\" of the energy and chemical industry chains, safe operation is of paramount importance in the storage and transportation sector. However, liquid level measurement in storage tanks has long faced challenges such as medium corrosion, leakage risks, high maintenance costs, and complex operating conditions. With over 30 years of experience in this field, Dinghua Electronics continuously improves its products and technologies by leveraging its core patents related to external level measurement technology. This enables it to address the challenges associated with measurement in complex applications within the storage and transportation industry, thereby ensuring the safe operation and efficient management of storage tanks. The “three major challenges” in level measurement within the storage and transportation industry: monitoring risks arising from the properties of the measured fluids. In the petrochemical industry, the materials stored in tanks are often hazardous chemicals, representing significant sources of danger. Traditional contact-type instruments require installation through openings in the tanks, which entails the risk of hot work and can lead to safety accidents ； Some materials are highly corrosive; the contact parts of conventional level switches are prone to damage, which results in a short service life. Frequent replacements not only increase costs but also disrupt the normal operation of the tank area ； Some viscous media have a significant impact on the stability of measurements, such as crude oil and asphalt. Traditional plug-in level switches are susceptible to the effects of gums and impurities present in mixed oils; these substances can cause adhesion or scaling on the surfaces of the components in contact with the liquid, thereby reducing the stability of the instrument’s measurements. This leads to inaccuracies and false readings, and may even cause incorrect interlock responses, posing significant challenges to the safe management of storage areas and the scheduling of materials. The conflict between maintenance costs and production continuity: Traditional contact-type instruments require openings to be made in the tank for installation, which poses risks associated with hot work ； Furthermore, regular maintenance requires shutting down production and the tanks, which reduces the turnover rate of the tank area and indirectly increases the company’s operating costs. Driven by regulatory upgrades and the need for improved management efficiency, companies in the storage and transportation industry are imposing stricter requirements on the safety certification of instrumentation systems. It is necessary to establish Safety Instrumented Systems (SIS), and the level gauges used in such systems must meet the requirements of \"Safety Integrity Level Certification\" (SIL). The ELL ultrasonic external level switch is a type of level switch that utilizes the principle of attenuation of ultrasonic waves as they propagate through a wall, combined with \"frequency-modulated ultrasonic\" technology for detection; it operates on a resonance-based principle. The measuring probe is attached to the outer wall of the container; it is a completely contact-free, isolated instrument for detecting liquid levels from outside the tank. Its design and operating principle help to avoid issues such as medium corrosion, installation risks, and maintenance difficulties, and it has been widely used for detecting liquid levels in various liquids within the storage and transportation industry. Next, let’s take a look at some recent application examples of external level switches: a company in Shandong Province https://nwzimg.wezhan.cn/contents/sitefiles2057/10285453/images/56785632.png ■ Background of the case: A liquid ammonia sphere tank with a diameter of 18 meters; the medium in question constitutes a major hazard source and is highly volatile ； Traditional instruments require drilling for installation, pose a high risk of fire, and are prone to corrosion ； The spherical tank has no pre-existing holes, and conventional measurement methods cannot balance safety and accuracy, resulting in high maintenance costs. ■ Solution: The technical engineers at Dinghua Electronics recommend that customers use ELL ultrasonic external level switches. These switches require no drilling or welding; the custom-shaped probe can be fitted to the curved surface of the spherical tank, allowing for measurement from outside the tank without any contact with liquid ammonia. Moreover, installation can be carried out without interrupting production. https://nwzimg.wezhan.cn/contents/sitefiles2057/10285453/images/56785611.png ■ Performance: Once in use, the switch ensures stable signals, requires no maintenance, and operates efficiently; it completely solves the installation and measurement problems associated with high-risk scenarios. Companies highly appreciate its safety and convenience advantages. A company in Zhejiang: https://nwzimg.wezhan.cn/contents/sitefiles2057/10285453/images/56785612.jpg ■ Case background: The original contact-type level switches had a high rate of false alarms due to sticking and aging, and replacing them required drilling holes for installation, which posed safety risks. ■ Solution: Since this unit has been using Dinghua Electronic level sensors with good results, ELL ultrasonic external level switches will continue to be considered for replacement. The switch is mounted magnetically on the tank wall (without the need for welding). Thanks to \"frequency-variable ultrasonic technology,\" interference and drift are eliminated, allowing for accurate detection of signal changes. Additionally, the \"micro-vibration analysis\" technique for processing acoustic signals helps reduce the impact of medium adhesion to the tank wall on measurements, thereby ensuring their reliability. ■ Effect of use: Contactless measurement is safer; Dinhua Electronics’ proprietary technology eliminates the interference caused by medium adhesion on the instrument, resulting in more stable instrument signals and more reliable monitoring, which has earned high praise from enterprises. A company in Zhejiang ■ Case background: The user’s diesel storage tank needed to undergo technical upgrades within a specified time frame; traditional contact-based methods required opening the tank and using fire, which posed high risks ； Moreover, the tank area needs to operate continuously; shutting down operations for installation would result in high costs and long lead times, making it difficult to meet the enterprise’s needs for efficient storage and transportation. ■ Solution: After a series of evaluations and comparisons, the user ultimately chose the ELL ultrasonic external level switch. The measurement probe is attached directly to the outside of the tank wall, and the customer service staff used the existing wiring to connect it to the DCS system quickly, completing the installation and modification for the customer within a few hours without any interruption in production. Furthermore, this device has obtained SIL3 certification as well as relevant explosion-proof certifications, fully meeting the requirements for measurements in high-hazard environments. ■ Effect of use: After installation, the signal remains stable without noise, and the interference resistance is significantly improved. This helps customers reduce their annual maintenance costs substantially, making level monitoring easier. The core advantages of the ELL ultrasonic external level switch: Frequency-variable ultrasonic technology. Through its patented adaptive \"frequency-variable ultrasonic technology\", Dinghua Electronics is able to eliminate the interference caused by deposits on the tank walls, as well as signal drift resulting from changes in temperature and time, thereby ensuring stable detection over the long term. It is suitable for various complex operating conditions, addressing the issue of poor reliability in traditional switches. 2. Safe and reliable isolated measurement: As a completely contactless instrument, the measuring probe of the ELL ultrasonic external level switch only needs to be attached to the outer wall of the container; there is no need to make holes in the tank wall, install flanges, or come into contact with the medium inside the tank, thus eliminating the risk of leaks entirely. This isolated design makes it particularly suitable for measuring hazardous liquids that are toxic and harmful (such as liquid chlorine and liquid ammonia), flammable and explosive (such as liquefied petroleum gas and ethylene oxide), highly corrosive (such as hydrofluoric acid and sulfuric acid), or high-pressure and volatile. It can even be deployed safely in renovation projects where storage tanks cannot be shut down and emptied. 3 High-precision level detection offers industry-leading accuracy in level measurement, reaching up to ±1mm, thus meeting the requirements for accurate alerts in demanding operating conditions. 4 SIL3 functional safety certification: Certified to the SIL3 functional safety level by the Certification Body (CNAS), suitable for Safety Instrumented Systems (SIS). SIS systems are now widely used in industries such as chlor-alkali, petrochemicals, and coal chemical processing; for example, they enable interlock shutdowns when the liquid chlorine storage tanks reach high liquid level levels, as well as protection against pump cavitation when the liquid nitrogen storage tanks have low liquid levels, thereby effectively reducing the likelihood of serious safety accidents. 5. Easy installation and maintenance: Magnetic or strongly adhesive probes are used, eliminating the need for welding, tank cleaning, or production interruptions. Installation can be completed by a single person within 30 minutes, significantly reducing construction costs and time. 6 Wide application versatility: It can be used in a wide range of applications, unaffected by the pressure, temperature, density, dielectric constant, viscosity, or corrosiveness of the medium. It supports various types of tanks, including spherical tanks, horizontal tanks, vertical tanks, railway tank cars, and on-vehicle storage tanks. For scenarios where non-metallic tanks are used or where there is no space for installation at the bottom of the tank, this system can make use of deflectors or customized installation solutions, thereby enabling truly flexible adaptation with a solution tailored to each individual tank. △Click to learn more about the ELL ultrasonic external level switch. Thanks to its frequency-variable ultrasonic technology, SIL3 safety certification, contactless design, and high reliability, the ELL ultrasonic external level switch is widely used in industries such as petroleum, chemicals, storage and transportation, and chlor-alkali production; it has thus become the preferred solution for monitoring the liquid level in tanks storing hazardous materials!