1, The types of flanges according to the national norm: integral flange, threaded flange, weld neck flange, with flat welding neck flange, Socket Weld neck flange, butt welding band neck loose flange, plate, Slip on flange, butt welding plate loose flange rings, flat welding ring plate loose flange, flange ring plate loose flange, flange cover.
2, The types of flanges according to the chemical industry norm: integral flange (IF), threaded flange (Th), plate flat welding flange diameter (PL), with butt welding flange (WN), with flat welding neck flange, socket welding flange (SO) (SW), the butt welding ring loose flange (PJ/SE), flat welding ring loose tube flange (PJ/RJ), lining flange cover (BL (S)), flange cover (BL).
3, The types of flanges according to the petrochemical industry norm: threaded flange (PT), weld neck flange (WN), Slip on flange (SO), Socket Weld flange (SW), loose flange (LJ), flange cover (not table).
Slip on flange of steel, is suitable for the nominal pressure of not more than 2.5 MPa carbon steel pipe connection. Slip on flange sealing surface can be made into smooth type, concave and convex type and mortise type 3 kinds. Smooth and Slip on flange are the largest. In the condition of medium is more moderate cases, such as suit low circulating water, the purification of compressed air, and it has the advantage of the price is cheaper;
Weld neck flange: suit for flange and pipe welding, its structure is reasonable, the strength and stiffness is bigger, can withstand high temperature and high pressure curve and temperature fluctuation, and repeated the sealing is reliable. Nominal pressure of 0.25 ~ 2.5 MPa weld neck flange with concave and convex type sealing surface.
Socket Weld flange: often used in PN acuities were 10.0 MPa, DN acuities were 40 pipeline;
Flange, flange come loose flange, commonly known as loop points welding ring flange, flange flanging live live flange and butt weld ends. Often used in medium temperature and pressure is not high and strong corrosion conditions. When strong corrosive medium, part of the flange contact medium (flanging nipple) as the corrosion resistance of high grade materials such as stainless steel materials, while the external use of low grade materials such as carbon steel material of flange ring clamp it in order to realize the seal;
Integral flange: often the flange and the equipment, pipes, pipe fittings, valves, etc, this type of commonly used on the equipment and valves.
Sealing surface forms: plane (FF), DCS (RF), convex (M), convex (F), concave and convex surface (MF) and groove (T) groove surface (G), grooved surface (TG), RTJ (RJ).
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)