In pipeline engineering, flanges are mainly used for connection of pipelines. In the pipelines that need to be connected, install a piece of flange, low-pressure pipelines can use wire flanges, and welding flanges for pressures above 4 kg. Add sealing points between the two flanges, and then tighten with bolts. Different pressure flanges have different thicknesses and use different bolts. When the water pump and valve are connected to the pipeline, some parts of these equipment are also made into corresponding flange shapes, also called flange connection.

All the connecting parts that are closed at the same time by using bolts on the two planes are generally called "flanges". For example, the connection of ventilation pipes, this type of parts can be called "flange parts". But this connection is only a part of the equipment, such as the connection between the flange and the water pump, it is not easy to call the water pump "flange parts". Smaller ones, such as valves, can be called "flange parts".