Square flange， flange is divided into threaded connection (threaded connection) flange, welding flange and clamp flange. Flanges are used in pairs, wire flanges can be used for low-pressure pipes, and welded flanges for pressures above 4 kg. A gasket is added between the two flanges and then tightened with bolts. The thickness of flanges with different pressures is different, and the bolts they use are also different. When water pumps and valves are connected to pipelines, parts of these equipments are also made into corresponding flange shapes, also known as flange connections.
All connecting parts that are connected by bolts on the periphery of two planes and are closed at the same time are generally called "flanges", such as the connection of ventilation pipes. This type of parts can be called "flange parts". But this kind of connection is only a part of the equipment, such as the connection between the flange and the water pump, it is not good to call the water pump "flange parts". Smaller ones, such as valves, can be called "flange parts".