Flange, also known as a flange disc or raised rim. A flange is a component used for connecting shafts to each other and for joining pipe ends; it is also used on equipment inlets and outlets, such as reducer flanges. Flange connection or flange joint refers to a removable connection formed by the combination of a flange, gasket, and bolt as a sealed assembly. Pipe flanges are the flanges used in piping installations, while on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes for bolts, which secure the two flanges together. The space between flanges is sealed with a gasket. Flanges come 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 above 4 kg pressure require welding flanges. Two flange disks are fitted with a sealing pad and then secured with bolts. Flanges of different pressures have varying thicknesses and require different bolts. In the case of pumps and valves, when connected to pipes, these equipment components are also shaped to match the flange, also known as flange connections. Any connection piece that uses bolts to connect two flat surfaces and seal them is generally called a "flange," such as the connection of ventilation pipes, which can be referred to as "flange-like components." However, such connections are 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-like component." Smaller items like valves can be referred to as "flange-like components."