Raised face flange (RF), female and male flange (M/FM), RTJ flange.
For toxic medium, as long as it's not extreme harm level, stress level is less than or equal to 1.6 MPa, usually can use surface RF flange, 2.5 MPa began generally require the use of concave and convex surface of the pipe flange. For extremely dangerous medium, need to use the concave and convex surface of the pipe flange.
Female and male pipe flange is commonly used in the German standard and national standard of PN4.0, PN6.4 MPa grade, mainly determined by the stress level, female and male pipe flange sealing surface is better than RF flange, but not easy to replace the gasket. The usage of grooved surface pipe flange with concave and convex surface are basically the same.
RTJ flange is mainly used in high temperature and high pressure, or both high condition. In the American standard pipe flange, commonly used in Class 600 lb (part), 900 lb, 1500 lb, 2500 lb classes. In Germany standard flange and is commonly used in national standard flange in PNl0.0, PN16.0, PN25.0, PN32.0, PN42.0 MPa in the pipe flange. The sealing gasket is used stainless steel ring.
General toxic and harmful medium, are not recommended to choose the ordinary plane flange and the RF flange, should choose or concave and convex surface is better than the sealing performance of the pipe flange.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)
