Little knowledge about pipe expansion joints

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This post was last edited by B0SS on 2019-10-28 at 17:35. Pipe expansion joints are mainly classified into three types based on their structure: elbow-type expansion joints, bellows expansion joints, and sleeve expansion joints. 1. Elbow-type expansion joint: An elbow-type expansion joint involves bending the pipe into a U-shaped shape or another configuration, and utilizing the elastic deformation capability of this shape for compensation. Its advantages are good strength, long service life, and the ability to be manufactured on-site; its disadvantages are large space consumption, high steel usage, and high frictional resistance. This type of expansion joint is widely used in various steam pipelines. 2. Bellows expansion joint: A bellows expansion joint is a type of expansion joint made from a metal bellows. It can extend and contract along the axis direction, and also allows a slight amount of bending, being used on pipes for axial length compensation. When in use, protective pull rods or protective rings are installed at both ends of the bellows, and guide brackets are provided on the pipes connected to its ends. There are also elbow-type and transverse expansion joints, which can be used to compensate for the angular and lateral deformation of pipes. The advantage of this type of expansion joint is that it saves space and material, and facilitates standardization and mass production; the disadvantage is its shorter lifespan, and it is generally used in pipes with moderate temperatures and pressures and relatively short lengths. 3. Casing expansion joint: The casing expansion joint consists of an inner casing and an outer casing that are capable of moving relative to each other in an axial direction, with a stuffing box being used for sealing between them. When in use, ensure that the tubes at both ends move along the same axis, and install guide supports at both ends of the expansion joint. Its advantages are low flow frictional resistance for fluids and a compact structure; the disadvantages are poor sealing performance and high thrust on the fixing brackets. Sleeve expansion joints are mainly used in water pipelines and low-pressure steam pipelines.