Flange, also known as a flange disc or raised rim. A flange is a component used for interconnecting shafts, serving as a connection point for pipe ends; it is also used at equipment inlets and outlets for connecting two devices, such as a reducer flange. Flange connection or flange joint refers to a detachable joint consisting of the flange, gasket, and bolt, all interconnected as a combined sealing structure. Pipe flanges refer to flanges used for piping in pipe assemblies, or in equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure them tightly together. Seals are used between flanges. Flanges are available in threaded (screwed) connections,焊接 (welded) flanges, and clamping flanges. Flanges are always used in pairs; low-pressure pipelines can use threaded flanges, while those over 4 kg pressure typically use焊接 flanges. Two flange discs are sealed with a gasket and then fastened with bolts. Flanges of different pressures have varying thicknesses and require different bolts. When pumps and valves connect to pipelines, the respective parts of these equipment are also made into corresponding flange shapes, also known as flange connections. Any connection component that uses bolts to connect and seal two flat surfaces is generally called a "flange," such as the connection of ventilation pipes, which can be referred to as "flange-type components." However, such a connection is only a part of a device, like the connection between a flange and a pump, where it would not be appropriate to call the pump a "flange-type component." Smaller items like valves can be referred to as "flange-type components."