Flange, also known as a flange boss or rim. A flange is a component used for connecting shafts or for joining pipe ends; it is also used on equipment for connecting two devices, such as a reducer flange. Flange connection or flange joint refers to a detachable joint consisting of a flange, a gasket, and bolts, which together form a combination seal structure. Pipe flanges are the flanges used for piping in pipe systems, and on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes for bolts to secure them tightly together. They are sealed with a gasket. Flanges come in threaded (screwed) connections, welded flanges, and clamped 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 discs are joined with a sealing pad and then bolted together. Flange thickness varies with pressure, and so does the type of bolt used. Pumps and valves, when connected to pipes, have local components shaped as corresponding flanges, also known as flange connections. Any connection piece that uses bolts to join two flat surfaces around the periphery and is sealed is generally called a "flange," such as in the connection of ventilation pipes. These components can be referred to as "flange-type parts." 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-type part." Smaller items like valves can be called "flange-type parts."