In terms of flanges/flange plates, although most people are unfamiliar with the concept, they are actually indispensable to everyone in the city. Flanges are widely used for the interconnection of various high and low-pressure pipelines, such as the urban water supply pipeline network, the drainage pipeline network of sewers, the heating circulation pipelines for winter boiler heating, and energy pipelines like oil and natural gas, etc. Their role in pipelines is akin to the connecting sections between tracks on the familiar railway.