Flange is a part connecting pipes, which is used to connect pipe ends. It is also useful for the flange on the inlet and outlet of equipment, which is used for the connection between two equipment, such as the flange of reducer. Flange connection or flange joint refers to a detachable connection with flanges, gaskets and bolts connected to each other as a set of combined sealing structures. Pipeline flange refers to the flange used for pipes in pipeline equipment, and refers to the import and export flange of equipment when used on equipment. There are holes in the flanges, and bolts make the two flanges tightly connected. The flanges are sealed with gaskets. Flanges are divided into threaded (threaded) flanges, welded flanges and clamping flanges. Flanges are used in pairs. thread connection flanges can be used for low-pressure pipelines, and welded flanges can be used for pressures above four kilograms. Add a gasket between the two flanges and fasten them with bolts. Flanges with different pressures have different thicknesses, so they use different bolts. When pumps and valves are connected with pipelines, the parts of these equipment are also made into corresponding flange shapes, which is also called flange connection. All connecting parts that are bolted and closed at the same time around two planes are generally called “flanges”, such as the connection of ventilation pipes, which can be called “flange parts”. However, this connection is only a part of equipment, such as the connection between flange and water pump, so it is not good to call the water pump “flange parts”. Smaller ones, such as valves, can be called “flange parts”. Reducer flange is used for the connection between motor and reducer, and the connection between reducer and other equipment.