Should the control valves installed on LNG pipelines be connected by flanges or by welding?
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The last edit to this post was made by Desert Fish on 2021-7-30 at 13:43. The control valves installed on LNG pipelines vary depending on the specific project; in the same process and at the same location, some use flange connections while others use welding connections. I’d like to hear everyone’s opinions on which of the two forms is better
If welding is possible, use flanges instead
Currently, welded valves are generally used
The control valves installed on LNG pipelines must be of the welded type; the main purpose is to ensure safety.
There’s no rule saying it has to be used, right? It’s also just for safety reasons; welding is a good option, but flange connections have also been used in such cases
Replacing flange connections with welding simply reduces the number of leakage points, thereby enhancing safety fundamentally, right? Not necessarily. In my opinion, in terms of engineering and management, strict quality control, along with timely inspection and maintenance, are the key to ensuring safety. Additionally, since welding is used everywhere, when there are engineering requirements such as system modifications or repairs that involve re-warming and replacement, production managers face difficulties. I believe that, taking into account the needs of production management, it makes sense to use valves with flange connections in certain areas
Just like a bicycle chain cover, an open one is prone to chain loss, but it is easy to repair. Closed ones are less likely to fall off, but once they do, it’s harder to fix.
For safety reasons, welding is preferred; try to avoid using flange connections