Weld Neck Flange standard system

There are two main international standards for Weld Neck Flange, that is, the European pipe flange system represented by the German DIN (including the former Soviet Union) and the American pipe flange system represented by the American ANSI pipe flanges. In addition, there are Japanese JIS pipe flanges, but generally only used for public works in petrochemical plants, and has a relatively small international impact. Pipe flange is now introduced in various countries under the following:

(1) The European system pipe flange represented by Germany and the former Soviet Union

(2) American System Pipe Flange Standard, represented by ANSI B16.5 and ANSI B 16.47

(3) British and French pipe flange standards, each with two sets of pipe flange standards.