A flange, also known as a flange flange or flange, is a part used to connect shafts to shafts, pipe ends to pipe ends, or equipment inlet and outlet. The flange connection is a detachable sealing structure formed by combining flange, gasket and bolt . The flange is provided with holes, and the two flanges are closely connected by bolts, and the gasket is used to seal them. Flanges are divided into threaded joint flanges , welded flanges and clip flanges , and are usually used in pairs. Wire flanges can be used for low pressure pipes, while welded flanges are used for pipes with pressures of more than four kilograms. Different pressure flange thickness and the use of bolts are also different. In addition, when the equipment such as water pump  and valve  is connected with the pipeline, its part may also be made into a flange shape, also known as a flange connection. Connecting parts that are bolted and closed at the perimeter of two planes are often referred to as "flanges", such as the connection of ventilation ducts. However, if this connection is only a part of the device, such as a part of the pump, the entire pump will not be called a "flanged part." For smaller equipment such as valves, it can be called "flanged parts".