1. Basic parameters: nominal pressure PN, nominal diameter DN
2. Basic functions: cut off and connect the medium, adjust the flow rate, and change the flow direction
3. The main connection methods are: flange, thread, welding, and clamp
4. Pressure-temperature grade representation: different materials and different working temperatures have different maximum allowable non-impact working pressures
5. There are two main systems for pipe flange standards: the European system and the American system. The pipe flange connection sizes of the two systems are completely different and cannot be matched;
It is most appropriate to distinguish by pressure level:
The European system is PN0.25, 0.6, 1.0, 1.6, 2.5, 4.0, 6.3, 10.0, 16.0, 25.0, 32.0, 40.0MPa;
The American system is PN1.0 (CIass75), 2.0 (CIass150), 5.0 (CIass300), 11.0 (CIass600), 15.0 (CIass900), 26.0 (CIass1500), 42.0 (CIass2500)MPa.
The main types of pipe flanges are: integral (IF), plate flat weld (PL), slip-on welding (SO), welding neck flange(WN), socket weld (SW), screw (Th), butt weld sleeve (PJ/SE)/(LF/SE), plate flat weld sleeve (PJ/RJ) and blind flange (BL).
The main types of flange sealing surfaces are: full flange (FF), raised flange (RF), female flange (FM), male flange (M) , tongue (T) groove (G) face, ring joint face (RJ), etc.
