Can convex and protruding flanges be connected?
Thread Content
Can convex and protruding flanges be connected? Please everyone share your thoughts
I think there is no problem with this.
Recently we encountered this issue; we accidentally came across something from a previous training session, where a teacher from Global said that sometimes it is possible to establish a connection
It is not standard; the dimensions of its sealing surfaces vary, which can easily damage the gasket.
According to the specifications, it shouldn’t be possible; it depends on factors such as the pressure load and the medium used!
It should be possible to connect them, as long as the flange specifications and pressure ratings are the same. But this is not the standard practice. The diameters of the protrusions on the two are different, resulting in uneven compression of the gasket and making it difficult to ensure a proper seal.
After all, it are different types of flange sealing surfaces, so the sealing effect cannot be guaranteed. Moreover, if the distinction is not taken into account during design and construction, it becomes very difficult to manage things. What if two convex flanges are used together? Therefore, it is not recommended to use them together.
It’s fine for emergency use; raised gaskets should be used. What’s mentioned here is only regarding short-term use, as long-term use is not possible. The outer diameters of the two types of gaskets are different – for example, the outer diameter of RF PN40 DN100 is 162, while that of the M-type gasket is only 149, resulting in a difference of 12 mm in the force application point. This does not meet the sealing requirements for long-term use. The difference is even greater in other cases: the outer diameter of RF PN40 DN300 is 410, whereas that of the M-type gasket is only 363, giving a difference of 47 mm. For DN600, the difference is 60 mm. All of these represent potential problems
This time, valves with two RF surfaces were designed. However, the supplier provided valves with two concave surfaces along with four RF-faced flanges. Then he said that the RF surfaces needed to be made convex. I checked the dimensions specified in the standards and found that it was possible to carry out such processing, but I’m a bit worried about the performance!
It’s better not to do it. Unless it’s a special case, aside from the impact on sealing performance, there’s also the risk that the components won’t fit together properly, making it impossible to install them correctly and leading to more problems in the end.