Understanding of Article 37 of the Regulations
Thread Content
“Article 37 When designing storage containers for liquefied petroleum gas, the regulations of industry standards HG20592~20635 should be followed and pipe flanges, gaskets and fasteners with a pressure level higher than the design pressure should be selected. The first flange sealing surface should be a combination of high-neck butt-welding flange, metal spiral wound gasket (with outer ring) and high-strength bolts. ” I "Metal wound gasket (with outer ring)" Whether the flange sealing surface must be in RF form
As long as it is a metal wound gasket, it can be with an outer ring, an inner ring or an inner and outer ring. Therefore, the form of the flange sealing surface can be RF or concave and convex.
Agree with the opinion above. High neck butt welding flange (WN) sealing surface type (HG20595): Raised surface (RF), concave and convex surface (MFM), tongue and groove surface (TG), ring connection surface (RJ), full plane (FF) metal flat wound gasket (JB/T6369-1992): Basic type, with inner ring type, outer ring type, both internal and external type. For reference only.
"With outer ring" in Article 37 of the regulations refers to the situation when the RF sealing surface is used.
Let's take a look at page 277 of HG20592-HG20635-97. The sealing surface forms of the metal spiral gasket are raised surface, concave and convex surface and tongue and groove surface, but the C type with outer ring only uses raised surface. You will know it by looking at its size. What is said above is still correct.
However, the size of the lining ring exceeds the inner diameter of the flange. What's going on?