Flange, also known as a flange disc or raised rim. A flange is a component used for connecting shafts to each other, serving as a connection point for pipe ends; it's also used on equipment for connections between two devices, such as a reducer flange. Flange connection or flange joint refers to a removable connection that consists of the flange, gasket, and bolt, all interconnected to form a combined sealing structure. Pipe flanges are the flanges used in piping installations; on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts are used to tightly secure the two flanges together. They are sealed with a gasket. Flanges come in threaded (screwed) connections,焊接 (welded) flanges, and clamp flanges. Flanges are always used in pairs; low-pressure pipelines can use threaded flanges, while those above four kilograms of pressure use welded flanges. Two flange discs are joined with a sealing pad and then bolted together. Flanges of different pressures have different thicknesses and require different bolts. Pumps and valves, when connected to pipes, have locally shaped flanges corresponding to these equipment components, also known as flange connections. Any connection piece that uses bolts to connect two flat surfaces around the edges and is sealed is generally called a "flange," such as the connection of ventilation pipes. Such components can be referred to as "flange-type parts." However, this type of connection is only a part of a device, like the connection between a flange and a pump, so it's not appropriate to call the pump a "flange-type part." Smaller components like valves can be called "flange-type parts."