Different pressure flanges have different thicknesses and use different bolts. When pumps and valves are connected to pipelines, parts of these devices and equipment are also made into corresponding flange shapes, also known as flange connections. Whenever the connecting parts closed together by bolts in two planes are generally called "flange", such as the connection of ventilation ducts, this type of parts can be called "flange parts". However, this connection is only a part of a device, such as the connection of a flange and a water pump, it is difficult to call the water pump a "flange type part".
The flange gasket has been replaced by a sealing ring to ensure that the seal faces the sealing surface. Only a small amount of pressure is required to compact the cover. As the required pressure decreases, the specifications and number of bolts can be reduced accordingly.