Flange, also known as a flange disk or rim, is a component used for connecting shafts to each other or for joining pipe ends. It is also used at equipment inlets and outlets, such as on a reducer flange. A flange connection or flange joint refers to a removable joint consisting of a flange, a gasket, and bolts, which together form a sealing assembly. Pipe flanges are those used in piping systems, while equipment flanges refer to the inlets and outlets of a piece of equipment. Flanges have holes and are secured together with bolts, with a gasket used between them for sealing. 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 four kilograms of pressure use焊接 flanges. Two flange disks are joined with a sealing gasket and then tightened with bolts. Flanges of different pressures have different thicknesses and require different bolts. Pumps and valves, when connected to pipelines, have corresponding flange shapes at the local connection points, also known as flange connections. Any connection piece that uses bolts to connect two flat surfaces around the periphery and is sealed is generally called a "flange," such as the connection of ventilation pipes. These types of components can be referred to as "flange-type parts." However, such connections are only a part of a single piece of equipment, 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 referred to as "flange-type parts."