Before trenching the pipeline, a thorough inspection of the surface protective coating at the intersection needs to be conducted. Any damage to the protective coating should be addressed promptly.
Ensure the alignment and gradient of the pipeline during the pipeline connection.
Three, pre-insulated pipe can be suspended individually into the trench for installation, or two or more pipes can be organized and lifted after welding. When the assembled pipe is long, it is recommended to use two or more cranes to lift the pipe, with the lifting points selected based on the balance conditions. It is prohibited to push the pipe directly into the trench.
Upon completion of the welding of the working steel pipes and their passing inspection, the insulation of the joints and the connection of the outer casing can be addressed. The聚氨酯 foam can be initially molded. Then, use heat shrink tape to seal the joint area overall, overlapping each side and the branch pipe by 100mm. Alternatively, the outer casing can be welded first, and after passing the sealing inspection, the holes can be drilled for foam injection.
Five, upon completion of the day's engineering work, the pipe ends should be sealed with a blind plate to prevent mud and water from entering the pipes.
Six: There are three installation methods for pre-insulated pipe: cold installation, hot prestressed installation, and one-time compensator installation.
Seven, Cold installation involves directly connecting the sections of the pipe and, upon passing inspection, backfilling according to standards. Eight, Hot prestressed installation requires preheating the pipeline to 60% of the operating temperature before welding, followed by backfilling and compaction.
Nine: The compensator must be welded when the pipeline temperature reaches 60% of the operating temperature, followed by backfilling and compaction.
