A flange, also known as a flange or flange. A flange is a component that connects shafts and is used for connecting pipe ends; Also useful are flanges on the inlet and outlet of equipment, used for connecting two devices, such as gearbox flanges. A flange connection or flange joint refers to a detachable connection formed by a combination of flanges, gaskets, and bolts connected together as a sealing structure. Pipeline flange refers to the flange used for piping in pipeline equipment, and when used on equipment, it refers to the inlet and outlet flanges of the equipment. According to the different nominal pressure levels of valves, flanges with different pressure levels are configured in pipeline flanges. In this regard, German engineers from Ward WODE introduce several commonly used flange pressure levels according to international standards:

According to ASME B16.5, steel flanges have 7 pressure ratings: Class150-300-400-600-900-1500-2500 (corresponding national standard flanges have PN0.6, PN1.0, PN1.6, PN2.5, PN4.0, PN6.4, PN10, PN16, PN25, PN32Mpa ratings)

The pressure rating of the flange is very clear. Class300 flanges can withstand greater pressure than Class150 because Class300 flanges need to be made of more materials to withstand greater pressure. However, the compressive capacity of flanges is influenced by multiple factors. The pressure rating of a flange is expressed in pounds, and there are different ways to represent a pressure rating. For example, the meanings of 150Lb, 150Lbs, 150 #, and Class150 are the same.