Flange, also called flange flange or flange. Flange is a part that connects between shaft and shaft, used for connection between pipe ends; it is also useful for flange on equipment inlet and outlet, used for connection between two equipment, such as reducer flange. Flange connection or flange joint refers to a detachable connection in which flanges, gaskets and bolts are connected to each other as a set of combined sealing structures. Pipe flange refers to the flange used for piping in the pipeline installation, and refers to the inlet and outlet flanges of the equipment when used on the equipment. There are holes on the flanges and bolts make the two flanges tightly connected. The flanges are sealed with gaskets. The flange is divided into threaded connection (threaded connection) flange, welding flange and clamp flange. Flanges are all used in pairs, wire flanges can be used for low-pressure pipelines, 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 with pipelines, parts of these equipments are also made into corresponding flange shapes, also called 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 kind of parts can be called "flange parts". However, this 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".