Answer to the question “Setting of radar level gauges on spherical tanks”
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When selecting two level gauges, the primary consideration is the safety of the storage tank. SH-3136-2003 specifies that spherical tanks should be equipped with local and remote level gauges; glass plate level gauges are not suitable for use in such tanks. What I do is build two self-controlled level gauges with on-site indication. The options I have considered for level measurement in spherical tanks are as follows: 1) 2 servo-based systems (for transporting the finished product); 2) 2 radar systems, with waveguides required; 3) 1 servo-based system + 1 radar system; 4) 1 radar system + 1 differential pressure sensor (for intermediate storage tanks). Since the gas-liquid interface of liquefied hydrocarbons is not clearly defined, servo-based systems are the best choice, but they are also the most expensive. It is selected based on the owner’s financial conditions and needs; based on years of experience, glass panels definitely cannot be used, as nothing will be visible over time. This post was last edited by Storage and Transportation Engineer on 2009-2-14 08:49.]
Is it necessary to have 2 units, or can 1 unit meet the requirements?
I would like to ask what form is used for on-site indication of the spherical tank – is it a liquid crystal display that shows the measurement values from the radar level gauge? So, if the automation system fails, wouldn’t that cause big problems?
Two level gauges are necessary; one alone cannot meet the safety requirements. Experts from Japan and France all think the same way. We call it the “Yongyu” design, precisely to prevent the problems mentioned on the third floor. This important signal, thanks to its dual-channel design, definitely prevents the problems that were a concern on the 3rd floor. The owners I’ve encountered have all made similar requests. The local level gauges shown in the pictures were those used by the previous owners, and they caused many inconvenience in production. Solution: Both gauges should be remote-controlled level gauges; a liquid crystal display should be installed on the ground to enable inspection personnel to easily monitor the liquid level in the tank, as if it were at the surface level. This post was last edited by a Storage and Transportation Engineer on 2009-2-14 08:25
Thank you to the original poster! But is it necessary for both radar level gauges to have an accuracy of 1 mm?
Do radar level gauges have the problem of inaccurate measurements after being in use for a long time?
For finished product tanks, it is recommended to use a metering grade (i.e., ±1 mm as you mentioned). If budget permits, a servo type is advisable; one client has used two servo units for 10 years without any issues. For intermediate tanks, a process grade is recommended