Flange, also known as a flange disk or rim, is a component used for connecting shafts or for joining pipe ends. It is also used on equipment for connecting two devices, such as reducer flanges. A flange connection or flange joint refers to a detachable connection formed by the combination of a flange, gasket, and bolt as a sealed assembly. Pipe flanges are flanges used for piping in pipe systems, or for equipment进出口 flanges. Flanges have holes, and bolts are used to securely fasten the two flanges together. Gaskets are used to seal between the flanges. Flanges come in threaded (screwed) connections,焊接 connections, and clamp connections. Flanges are always used in pairs; low-pressure pipelines can use threaded flanges, while those above 4 kg pressure use焊接 connections. Two flange disks are fitted with a sealing pad and then bolted together. Flange thickness varies with pressure, as do the bolts used. Pumps and valves, when connected to pipelines, have corresponding flange shapes for local connections, 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 in ventilation pipe connections. Such 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."