Underwater pipelines, repair

The only alternative to the adhesive method for underwater pipelines repair is replacement. The cost of construction of underwater mains crossing large rivers amounts to 10-50 million dollars. The cost of repair by the adhesive method is 10-50 thousand dollars. These data were obtained for repair of pipeline junctions through the Volga, Yenisei, and Moscow rivers, and for operations in the Okhotsk Sea, in swamps near the river Goiyn (Belarus), in Bulgaria (Stevis Corporation), and from other projects. 

Because they are very quiet, and because they are inherently more efficient than diesel or other i.c. power plants, fuel cells have long been regarded by the navies of the United States, Germany, Canada, Australia, and Sweden as an attractive means of propelling small submersibles (such as unmanned underwater vehicles used for marine research, pipeline repair, salvage, and exploration), and even full-size submarines. 

Repair of underwater pipelines. Failiu-es of underwater pipelines are observed most often because of damage by ships or anchors. In rivers with strong currents, scours may appear beneath pipelines the pipelines sag, and as a result of the vibration and stresses generated, cracks may appear, most often observed in the weld area. The pipe... 

Shamsuddoha, M., Islam, M.M., Aravinthan, T., Manalo, A., Lau, K., 2013. Effectiveness of using fibre-reinforced polymer composites for underwater steel pipeline repairs. Composite Stmctures 100, 40—54. 

Acetylene, in combination with oxygen, burns with an intense flame that has diverse applications. It can be used for welding parts of a bridge underwater and for repairing an oil pipeline in Siberia. 

A limited number of stodies have been conducted on the internal repair of steel pipelines using composite material systems. As a consequence, only a few industries have used composite technologies for internal repair. In their report, Bruce et al. (2006) indicated that internal repair would have the best economics for underwater repair locations as it reduces out-of-service time and does not require divers and habitats. Such economics arise because the majority of the gas transmission line companies in the United States consider the ability of the pipeline to remain in service during internal repair to be very important. Moreover, they would considCT internal repair, even if the pipeline needs to be out of service (no flow), only if the pipeline remains pressurised and the line can still be inspected by a pipe inspection gauge after repair. However, these companies have indicated that they would consider performing a repair from inside the pipe once a proven and accepted internal repair system becomes available. Thus, the selection of the most appropriate technique of renovation, particularly on the internal repair of high-pressure and deep water pipeline applications, is a critical and ongoing issue. 

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