After reading the post on “Precautions for installing level gauges in internal floating roof tanks”, I’d like to share my thoughts
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Opinion: Attach a steel rope to the floating roof cover, attach a heavy object to the other end of the rope, and mark an arrow... Comment: I do not support this idea; friction between the steel rope and the pulley can generate sparks. One of the reasons given by explosion experts from Guangwei last year was the ignition caused by friction between the steel strip level gauge and the pulley. Based on the experience of one factory, there are frequent cases of jamming, and the factory requires that someone check the level at the end of each shift. Since the storage tank in question has an internal floating roof, it is not recommended to use differential pressure level gauges; the reason is that friction between the floating disk and the tank body leads to inaccurate measurements. My approach involves using a radar level gauge, along with a high-level interlock system (fork switch) and manual level checks. The radar level gauge sends data to the control room; it offers high precision and allows for direct conversion to volume values, with the data displayed clearly on the screen. Of course, it cannot be used as a basis for trade settlements – manual level checks should still be relied upon. I believe safety is of utmost importance, and besides, radar level gauges are not expensive. If automated control instruments are needed, everyone is welcome to share their opinions
The poster is absolutely right; the level signals here are fed directly into the DCS system, which facilitates various types of control and management. Those outdated systems are now rarely used in new installations
Similar to the original poster, I usually design a radar system together with a differential pressure sensor and manual control; the radar is used for control while the differential pressure serves as a reference. It is particularly useful at low liquid levels, when the floating disk has not risen above 1.8 meters.
1. Under normal operation, the level will not drop below 1.8 meters. When the floating disk has not risen, the vent valve at the top of the disk opens, allowing gas and liquid to mix and resulting in a large amount of steam being released; therefore, my design sets an alarm at 2 meters. 2. The floating disk experiences friction as well as the effect of gravity. Using differential pressure is simply not accurate, but the dome tanks I design all use a combination of differential pressure and radar.
Our factory uses steel belt level gauges, which also have remote transmission capabilities, and they perform quite well.
What medium is it, and when was it installed?