A brief discussion on the application of sonar-type external level gauges in petrochemical plants

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Level detection in liquefied gas spheres of petrochemical enterprises is quite complex. Radar level gauges or fiber optic level gauges are generally used, but in either case, holes must be made in the spherical tank. As pressure vessels, the more holes there are in such vessels, the lower their safety factor becomes. Sonar-based external level gauges help to avoid the need for making holes in liquefied gas spherical tanks. http://www.dhechina.com/ueditor/php/upload/image/20180621/1529546620219150.png　　　　A sonar-type external level gauge uses ultrasonic devices installed outside tanks and pipes to measure the liquid level in such devices. Ultrasonic signals are continuously transmitted through the outer wall of the device into the liquid being measured, and then the echo signals are detected by sensing elements. The reflected echoes from transmission and reception are related to changes in the height and density of the liquid being measured, and the measurement results are obtained through calculations by electronic circuits. The calculated measurement values can be digital output, analog, or digital. 　　In the application of sonar-type external level gauges, it is required that the liquid being measured contain a small amount of gas or solid particles. There should be no sediment at the bottom of the tank, or only a small amount. The tank body can be made of the same material (such as plastic, glass, stainless steel, carbon steel, etc.). 　　A sonar-type external level gauge uses a transmitting unit to emit ultrasonic waves through the container wall; the speed of these ultrasonic waves as they propagate through the liquid is between that of the signals reflected off the inner wall of the container and those reflected back from the liquid surface. The time difference of the reflected signals received by the ultrasonic sensor is proportional to the liquid level height, with any other multiple reflections being compensated for in the calculations. 　　A sonar-type external level gauge is used to measure continuous liquid levels. The ultrasonic sensor is installed at the bottom of the tank or container; the time difference taken by the ultrasonic waves to pass through the liquid indicates the liquid level height, which is then converted into an analog output signal. It can also provide digital output signals for alarms indicating high or low liquid levels. 　　The sonar-type external level gauge requires no welding or drilling; it is a type of external measurement method. Its installation is achieved through magnet attachment, making it extremely convenient for installation and maintenance. It is widely used in the petrochemical industry for measuring and controlling the level of spherical and horizontal tanks. 　　The sonar-type external level gauges produced by Dinghua Electronics utilize unique algorithms and cutting-edge technology to overcome the impact of liquid fluctuations caused by feed into storage tanks or temperature changes on level measurement, ensuring stable readings. It facilitates operation by installers, saves time, and improves efficiency.