What aspects should be considered during the installation of corrugated expansion joints during construction?

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Proper construction and installation of bellows expansion joint pipelines are crucial for the safe operation of the piping system. The basic requirements for pipeline construction are summarized as follows, in the hope that it will be helpful to pipeline workers! 1. Before installation, it is necessary to check whether the model, pressure, specifications of the bellows expansion joint, as well as the configuration of the pipe supports, meet the design requirements. 2. When welding the pipe supports and brackets, spot welding or incomplete welding is not allowed. 3. To ensure the coaxiality during the installation of the bellows expansion joint, the pipe section should be laid out first; then, the portion at the location where the expansion joint is to be installed should be cut off to a length equal to that of the compensator after pre-stretching, after which the bellows expansion joint is installed and welded in place. 4. The method of deforming the bellows expansion joint cannot be used to compensate for pipeline installation errors. 5. Ensure that the installation direction of the guide cylinder is consistent with the flow direction of the medium. 6. Only one axial corrugated expansion joint can be installed between the two fixed supports. 7. The corrugated expansion joints used in natural gas manholes are connected to valves and pipes via flanges. The expansion joints are generally installed in a horizontal position, with their axis aligned with that of the valves and pipes. It is not allowed to correct installation errors by adjusting the bolts on the flanges or by deforming the bellows; welding should only be carried out after ensuring that the bolt holes at both ends are properly aligned. 8. During installation, it is strictly prohibited for welding spatter to come into contact with the surface of the bellows, and it is also forbidden to create arcs or make electrical connections at any part of the bellows. 9. Before conducting the system pressure test, all fixing brackets, guide supports, and backing frames must be installed in place. 10. After installation, before the pressure test, the transport struts and limiting nuts must be removed or loosened; these accessories cannot be used as protective elements for the compensators during the pressure test. It is also necessary to ensure that all moving parts of the expansion joints are functioning properly. 11. During the pressure testing of gas pipelines, temporary brackets and supports should be installed to prevent the compensators and pipelines from sagging; however, these temporary brackets and supports must be removed after the testing is completed. 12. When conducting pressure testing on pipe sections using unrestrained bellows expansion joints, the intermediate fixing brackets must be reinforced to withstand the original design load in addition to the thrust exerted by the internal pressure blind flange. It is advisable to specify these requirements in the clauses on construction requirements within the piping system design documents, so as to alert the construction personnel.