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Ultrasonic external level switches play an important role in ensuring safe production in the petrochemical industry. In recent years, the safety situation in China’s petrochemical industry has become increasingly severe. Safety supervision agencies at all levels have raised their requirements regarding the safety of hazardous chemical storage areas in oil depots, and various safety management systems and measures have been introduced accordingly. Below, we will explain the significant importance of ultrasonic external level switches for ensuring safe production. The significance of ultrasonic external level switches for safe production: In accordance with the requirements set out in Document No. 116 issued by the former State Administration of Work Safety, titled \"Guiding Opinions on Strengthening the Management of Safety Instrumentation Systems in the Chemical Industry,\" for new installations, as of January 1, 2018, work safety supervision agencies across the country have gradually required that new projects falling under the category of \"two key areas and one major project\" undergo SIL grading and verification. For existing installations, the assessment of their safety instrumentation systems must be completed by the end of 2019, followed by necessary corrective actions. To meet the requirements for upgrading liquid level safety interlocks and ensure the safe operation of oil depots, Dinghua Electronics has developed a comprehensive solution for liquid level safety interlocks in storage tanks, tailored specifically for such facilities. This solution enables online monitoring of liquid level levels in storage tanks, as well as automatic shutdown of relevant valves and oil transfer pumps through programmed interlocks, thereby ensuring safety. It can completely eliminate operational accidents caused by human-induced delays in operations in practical applications, thereby achieving precise, safe, and effective control; it also meets the requirements of regulatory authorities at all levels for real-time monitoring of the safety management of oil storage tanks. The oil tank level safety interlock system consists of a level excess control unit, core control software, and device actuator control units. The level excess unit is essentially an overload level detection switch installed on the wall of the oil tank, which is used to detect any excessive level in real time and transmit signals to the core control unit located in the control room. The system is further composed of an intelligent level interlock terminal and a computer system, which enable real-time monitoring of the operation status of the overload level detection switch. Based on the logical control programs integrated within them, these components can trigger alarms automatically and shut down related valves, pumps, and other control devices as needed ； The equipment execution units are primarily the oil transfer pumps in the oil depot, as well as the electric valves and oil transfer pumps installed on the process pipelines. They are controlled by the core unit; upon receiving commands from this control unit, they carry out actions such as starting, stopping, etc. Once the entire command sequence is completed, the safety interlock protection functions are fulfilled. The above is an analysis of the significant importance of ultrasonic external level switches for safe production; it also sets strict requirements for the detection of excessive levels in oil storage tanks at the main facilities responsible for managing refined oil in the petrochemical industry, as well as for safety interlock protection systems. Let’s take a closer look at the ultrasonic external level switch: Principle of the ultrasonic external level switch: 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 walls, combined with \"frequency-modulated ultrasonic\" technology to carry out detection; it operates on a resonance-based mechanism. The measuring probe is attached to the outer wall of the container; it is a completely contact-free, isolated instrument for detecting liquid level from outside the tank. It can be widely used for level detection of various liquids. Features: Safety: When measuring liquids that are toxic, corrosive, under pressure, flammable, explosive, volatile, or prone to leakage, it does not use valves, connecting pipes, or fittings; there are no leakage points, and it does not come into contact with the liquids and gases inside the tank, making it highly safe. Even when the instrument is damaged or under maintenance, there is absolutely no possibility of leakage, poisoning, or explosion. Reliable and durable: Utilizing Dinghua’s advanced signal processing technology and manufacturing processes, it is reliable and durable. Accuracy: Up to ±1mm. Easy to install and maintain: No need for welding or tank cleaning during installation and maintenance, thus production is not affected. Wide applicability: Not restricted by the pressure, temperature, density, dielectric constant, viscosity, or corrosiveness of the medium being measured inside the tank. Technological leadership: Features unique self-diagnosis for faults, along with a design for transmitting fault signals over long distances ； The instrument comes equipped with lightning and surge protection, eliminating the need for an additional surge protector. It has obtained the SIL3 certificate by passing the “Functional Safety Integrity” level certification from the Shanghai Instrumentation and Automation System Testing Institute. Applications: Ultrasonic external level switches are suitable for measuring and triggering alarms at specific levels for various liquids in different types of containers. They can be widely used in industries such as petrochemicals, chemicals, oil depots, petroleum, power generation, liquid storage and transportation, and pharmaceuticals. It offers significant advantages in the field of accurate level measurement and alarm systems for pressure vessels, hazardous chemical liquids, flammable and explosive liquids, etc.