Flange, also known as a flange disc or boss, is a component used for connecting shafts or for joining pipe ends. It is also used at equipment inlets and outlets, such as reducer flanges, for connecting two pieces of equipment. A flange connection or flange joint refers to a removable connection formed by the combination of flanges, gaskets, and bolts. Pipe flanges are the flanges used in piping installations, while those on equipment refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure them tightly 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 4 kg of pressure use焊接 flanges. A sealant is placed between the two flange discs, and then bolts are used to fasten them. Flanges of different pressures have different thicknesses and require different bolts. When pumps and valves are connected to pipelines, the respective parts of these equipment are also made into corresponding flange shapes, known as flange connections. Any connection component that uses bolts to connect two flat surfaces and seal them is generally called a "flange," such as the connection of ventilation pipes. Such components can be referred to as "flange-type components." 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 component." Smaller items like valves can be called "flange-type components."
