Issues regarding the use of weight-driven valves in LNG storage tanks
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I’m a newcomer; my colleagues at the company said that weight-loaded valves should be used for the drainage pipelines of LNG storage tanks, and it’s a standard requirement. I’m curious that the drain pipe already has a shut-off valve; what’s the purpose of adding a weight valve? And on what standard is it required? Thank you
In the event of a problem with the emergency shut-off valve, or if there is an issue with the pipeline ahead of the emergency shut-off valve, the flow of liquid from the LNG storage tank is stopped completely. This action is usually linked to a plant-wide emergency shutdown, and it constitutes a level-1 emergency shutdown of the liquid flow pipelines, thereby preventing the shutdown of all equipment and pipelines both before and after the LNG pump
The emergency shut-off valve is installed on the pipeline outside the tank, while the weight-driven valve is located inside the tank. As long as the tank is not damaged, if any external pipeline is damaged, pressing the emergency stop button will lower the weight-driven valve, thereby preventing the liquid inside the tank from leaking out. Moreover, the emergency shut-off valve is affected by various factors such as instrument signals, instrument air, and mechanical actuators. It doesn’t work when it counts. The heavy cone valve is different.
Dual protection: one is the interruption of operation when the solenoid valve loses or gains power, while the weight serves as a mechanical mechanism to close the valve more quickly.
This post was last edited by mfxqy on 2020-6-22 at 18:45. I mean, aren’t internal pumps popular in large tanks these days? Why still study the weight-loaded valve?