Issues regarding the flanges of safety valves
Thread Content
It’s a 5-cubic-meter tank with a design pressure of 4 MPa. Everyone, what do you think should be the connection type for the safety valve on top of the tank: M or FM? Generally, FM is the standard connection type for valve ports, but I noticed that in the old design drawings the connection type for the safety valve was M. I’d like to ask everyone whether M or FM is better, and please explain why
It’s good to use FM, as it prevents the sealing surfaces from being damaged during transportation and storage.
Could you help think about why the M format was used originally?
Safety valves are generally FM. The M model may need to be custom-made, sorry
It’s really hard to think about, haha. It’s not necessary to use FM; if the sealing surface is properly protected, using M is also an option. It’s possible that the safety valve isn’t cast as a single piece; the flange was welded on later.
I just checked a few old projects, and they all use the M format. I don’t understand it; is there any teacher who can explain it?
The use of the M face on the flange sealing surface of the tank top safety valve is mainly to facilitate the installation of gaskets: the corresponding pipe end uses the FM face, and during installation, the gasket can be placed directly in the groove. The most troublesome aspect of installing MFM flanges is the difficulty in aligning the gaskets properly. . .
I browsed through HaiChuan’s old posts and came across this one: http://bbs.hcbbs.com/thread-192897-1-1.html. In section 12#, there is a sentence that reads: HG20592 stipulates that for pressure ratings of 4.0 MPa and above, flanges and valves should be used with male and female sealing surfaces. To prevent the sealing surfaces from being damaged during transportation or installation, the flange of a safety valve is usually designed with a female surface, while the flange that pairs with it has a male surface. However, I searched through HG 20592 for a long time but couldn’t find this information. Does anyone know where this statement can be found or which diagram explains it? If so, please provide the exact location so that I can continue my search and share the findings with everyone