Flange, also known as a flange disc or raised rim. A flange is a component that connects two shafts or joins pipe ends; it is also used at equipment inlets and outlets, such as reducer flanges. Flange connection or flange joint refers to a detachable connection made up of the flange, gasket, and bolt, which together form a combined sealing structure. Pipe flanges are flanges used for piping in pipeline installations; on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure the two flanges together. The space between flanges is sealed with a gasket. 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 use焊接 flanges. Two flange disks are joined with a sealing pad and then bolted together. Flanges of different pressures have varying thicknesses and require different bolts. Pumps and valves, when connected to pipelines, 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 and is sealed simultaneously is generally called a "flange," such as the connection of ventilation pipes, which 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."