Main Types And Specifications Of General-purpose Corrugated Expansion Joints

Corrugated expansion joints can be classified into single-layer and multi-layer corrugated expansion joints based on the number of expansion joint layers. Single-layer expansion joints consist of a single layer of pipe wall, are easy to manufacture, but generally have limited compensation capacity. Multi-layer expansion joints consist of multiple layers of pipe wall, similar to multiple thin-sheet springs, resulting in lower stiffness.

Compared to single-layer expansion joints, under the same total pipe wall thickness and corrugation, multi-layer expansion joints deform more easily, have greater compensation capacity, generate less stress during deformation, and have a longer fatigue life. Multi-layer expansion joints can meet the requirements of large compensation amounts and high pressure impacts. Under certain pressure, compensation amounts, and fatigue life, multi-layer expansion joints have smaller outer diameters and shorter lengths than single-layer expansion joints, resulting in a more compact structure, material savings, and easier manufacturing. Due to the smaller corrugation height, it is easier to install outer sleeves for protection, and installation, support, and spacing are convenient. When corrugated expansion joints are used in corrosive environments, multi-layer expansion joints only require corrosion-resistant materials for the inner and outer layers, thus saving precious metals. Sometimes, for corrosion protection, the inner and outer layers can be made of thicker materials. In addition, if the inner layer of the pipe wall cracks due to some reason, such as corrosion, defects, fatigue, or installation, even though the inner layer has leaked, the other layers can still play a sealing role. In this way, the multi-layer corrugated expansion joint is less likely to suffer sudden failure and can extend the maintenance cycle of the corrugated expansion joint.