Can valves connected by 2 butt weld flanges be without a straight pipe section in between? ?
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As the title suggests, under normal circumstances, pipe fittings connected using butt weld flanges generally require straight sections of pipe. So, should straight sections of pipe also be added between two valves connected in this way? ? Thank you! ! !
Of course, it’s possible to do that – by reducing one leakage point, two flanges, one gasket, and a set of bolts can be saved. However, it should be noted that many valves have a concave surface, which requires convex flanges on both sides. I would appreciate it if experts could provide further corrections; thank you!
Reply to 2# Yuwan007: It seems you’re mistaken. This kind of direct connection method is generally suitable for pipelines with lower pressure, and the valve connection surface type is RF, that is, a convex surface, not a bulged surface
It’s better to add a short section; as long as the construction goes smoothly, leaks can be avoided, and it also makes it easier to maintain the valves
Valves that already come with flanges can be connected and installed directly if they have the same pressure rating.
A straight pipe section needs to be added; otherwise, it seems difficult to insert the bolts as well~
As long as it is not connected to instruments or control valves, it can be connected directly.
The valves of the two RFs can be connected directly.
It’s possible at low pressure; we often do this as well. It is not allowed under high pressure; it must be installed in accordance with the installation requirements
Since flat-weld flanges are used for the piping system, it can be inferred that it is a low-pressure piping system, and there is no issue with the two valves being connected directly. It should be noted that if it is a ball valve, there may not be enough space when installing the bolts, which can make disassembly and maintenance difficult.
It is necessary to determine what type these two valves are, whether their operation may cause interference with each other, and also to consider the convenience of installation and maintenance. If none of these are issues, it is also possible to connect them directly without using straight pipe sections.