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 connections between two devices, such as reducer flanges. A flange connection or flange joint refers to a detachable connection consisting of a flange, a gasket, and bolts, all working together as a sealed assembly. Pipe flanges are flanges used in piping systems within equipment, specifically referring to the inlet and outlet flanges of the equipment. Flanges have holes and bolts are used to tightly secure them. They are 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 four kilograms of pressure require焊接 flanges. Two flange disks are joined with a sealing pad and then fastened with bolts. Flanges of different pressures have varying thicknesses and require different bolts. When pumps and valves are connected to pipelines, the respective parts of these equipment are also shaped like flanges and are called flange connections. Any connection component that uses bolts to connect two flat surfaces and seal them is generally referred to as a "flange," such as the connections in ventilation pipes, which can be called "flange-type 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-type component." Smaller items like valves can be referred to as "flange-type components."