Quotation for underwater maintenance and dismantling of sewage treatment plant - salvage, installation and replacement of underwater coupling in inlet pump room

Quotation for underwater maintenance and dismantling of sewage treatment plant - salvage, installation and replacement of underwater coupling in inlet pump room

Quotation for underwater maintenance and dismantling of sewage treatment plant - salvage, installation and replacement of underwater coupling in inlet pump room

1. Construction content and purpose; Due to long-term underwater corrosion, the variable diameter flange of pump 5 # is severely worn and needs to be replaced, and the coupling base is severely worn and needs to be replaced as a whole.

   
   

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2. Due to limited site construction, a three-layer platform needs to be built here to drill holes and plant reinforcement on the walls and concrete above. The production of the platform must comply with safety requirements. The platform requires a working face width of ≥ 1 meter, a thickness of ≥ 6mm, steel material, a guardrail height of 1.2 meters, and steel material with a diameter of ≥ 30mm (materials selected from the national standard and constructed in accordance with industry standards). Steel structure ladders with protective cages are required for personnel to climb up and down each level of the platform

3. Find the vertical center point of the pipeline and drill a hole above to install the suspension point (drilling holes on the floor is strictly prohibited), to ensure that the 1200cm diameter pipeline can be suspended vertically for installation.

4. Divers carry out underwater dredging, clean the garbage bags on the flange, and then perform underwater cutting to separate the flange screws of the coupling base and the flange of the variable diameter pipeline.

5. After underwater cutting is completed, the upper part of the water is cut and salvaged in sections. The elbow part is cut in sections again to ensure minimal deviation during installation, and then salvaged after cutting is completed. When cutting pipelines on water surfaces, it is necessary to ensure good ventilation, strictly implement the work permit system, and follow the process of ventilation before testing before operation. Ensure at least two ventilation fans and one combustible gas detector to prevent explosions in confined spaces; On site personnel are required to wear toxic and harmful gas detectors throughout the entire process to prevent accidents caused by inhalation of toxic and harmful gases.

6. Remove the guide rod, couple the base for underwater cutting of anchor bolts, and dismantle the concrete base by 5cm (repair during installation). The coupler must not be damaged and must be salvaged intact

7. The pipeline is salvaged ashore for surface debris removal, and then the variable diameter flange is cut and replaced. Cutting edges are processed by breaking, elbows are processed by breaking for welding and installation, and the interior and exterior of the pipeline are protected against corrosion.

8. After all replacements are completed, installation and construction can begin. First, clear the sediment on the underwater working surface to ensure that there is no sediment on the working surface (sediment is removed and discharged to the sand box of the sedimentation tank). Then, connect and install the coupler base underwater, drill holes and plant reinforcement bars underwater, with no less than 8 pieces, and use limit fixing at no less than 6 places. All underwater installation materials must be made of SS304 material (screws, brackets, etc.).

9. Then, the first section of the pipeline will be installed with underwater docking, and the variable diameter flange and coupling base will be installed and docked. All docking will be completed, and the elbow part will be suspended and docked from the fixed lifting point. After docking, electric welding will be carried out.

10. During the installation of pipeline support points, drill holes and plant reinforcement underwater to ensure the support effect between the pipeline and the wall.

11. Install the guide rod, and the diver will dock the guide rod and coupling base underwater, with holes drilled on top for installation and docking. All of the above have been completed for pump discharge acceptance results.