|
Many different facings for flanges exist, including various "tongue and groove" types which must be used pairs.
Only 3 types of facings are commonly used. The raised face flanges accounts for about 80% of all flanges used today. It's raised face is 1/16" high for 150# and 300# class flanges and ¼" for all other ratings. An interesting note is that suppliers catalogs give the overall flange length including the 1/16" raised face but exclude the ¼" raised face. I don’t know why they all do that. Just look out for it when you are to calculated overall dimensions and face to face dimensions. A ¼" can add up rather quickly. Flat face flanges are commonly used to join piping to the non-steel flanges typically found on the bodies of pumps and other equipment. It is also used to mat up with 125# cast iron valves and fittings. Flat faced flanges use a gasket whose outer diameter is equal to that of the flange. This reduces the risk of cracking non-steel flanges when the assembly is tighten. Ring joint facings is a more expensive facing option. It is considered to be the most efficient facing for high temperature and high pressure services. This facing is not as likely to be damaged in handling due to the fact that the surfaces that contact the gasket are recessed in the flange. The gasket is either an oval section or a octagon section. RTJ flanges are used primarily in the petrochemical industry. |
| Back to Main Site Page | Comments? | Back to Pipe Flange Page |
