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 between pipe ends; there are also flanges used at equipment inlets and outlets for connecting two pieces of equipment, such as a reducer flange. Flange connection or flange joint refers to a removable joint made up of a flange, a gasket, and bolts, functioning as a combined sealing structure. Pipe flanges are the flanges used for piping in pipeline installations; when used 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. Gaskets are used to seal between the flanges. Flanges are available in threaded (screwed) connections,焊接 (welded) flanges, and clamp flanges. Flanges are used in pairs; low-pressure pipelines can use threaded flanges, while those over four kilograms of pressure require焊接 flanges. Two flange discs are fitted with a sealing pad and then secured with bolts. Flanges of different pressures have varying thicknesses, and they require different bolts. When pumps and valves are connected to pipes, the respective parts of these equipment items are also made into flange shapes, also known as flange connections. Any connection piece that uses bolts to connect two flat surfaces around the periphery and is sealed is generally called a "flange," such as the connection of ventilation pipes, which can be referred to as "flange-like components." However, such a connection is only a part of a device, like the connection between a flange and a pump, making it inappropriate to call the pump a "flange-like component." Smaller items like valves can be called "flange-like components."