Why is the rubber expansion joint connected by flange?

A flange connection is a connection completed by two flanges, with flange gaskets, fastened with bolts.
Flange connection is an important connection method for pipeline construction. Flange connections are easy to use and can withstand large pressures. In industrial pipelines, flange connections are widely used. If a pipeline fails, it is easy to disassemble and test; connect the pipeline and keep a good sealing performance; if a section of pipeline has problems, it is easy to replace a section of pipeline.
Flange not only saves space and reduces weight, but more importantly, ensures that the joint part will not leak and has good sealing performance. Flange gaskets have been replaced by sealing rings to ensure that the sealing surface matches the sealing surface. Since the flange has good comprehensive performance, it is widely used in chemical industry, construction, water supply, drainage, petroleum, light and heavy industry, refrigeration, sanitation, plumbing, fire-fighting, electric power, aerospace, shipbuilding and other basic projects.
Flange rubber expansion joint is composed of metal casting or welding, using the principle of compression elastic deformation of rubber. The material is externally painted with high-strength anti-corrosion paint, and the connecting bolts of each department are made of high-strength carbon steel or stainless steel bolts. Because there is a certain gap between the body and expansion tube, so that it has a certain axial and radial displacement.