Diverless Subsea Pipeline Welding Repair Cabin Design And Key Problem Research

As the laying length and duration of subsea pipeline are extended gradually, accidents caused by pipeline damages are increasing, the prevention and response to damages and leakages are increasingly tough challenges. Till now, there is no mature repair technology in our country for deepwater pipeline’s repair, it is urgent to accelerate the independent research and development of deepwater pipeline repair technology and equipments.Based on in-depth study and comparing of deepwater repair technology, The first robot for underwater pipeline repair in our country was designed by this paper, which provide a promotion for the development in deepwater pipeline repair technology of our country.Firstly, the composition of the whole system and technology roadmap has been determined by the requirement of underwater pipeline welding process, the overall structure of welded carbin has also been designed. Then the numerical simulations of drainage and drying situations of welding carbin was taken, obtained drainage and drying process, provide a reference to optimize the structure and a reasonable choice of ancillary components.Furthermore, the work of diverless underwater pipeline welding repairs cabin’s design was completed which was composted of driving chamber, static jaw, welding chamber, heating chamber and gas circulation system and divided into three parts.The welding carbin was closed by the hydraulic cylinders, formed a confined spaces between welding carbin and pipeline; then the welding environment was get throgh draining and drying; next,the driving chamber which in the midle of welding carbin push the carbin rotated; finally, the torch moved out from welding chamber finished the welding of pipeline. The damaged pipeline was repaired though fillet welding connect sleeve and pipeline by the welding carbin, which was is acompact, adaptable to a certain range of calibre changes and can adopt GTAW and GMAW welding methods.In addition, an experiment was carried out on the fillet weld test with gaps because there exist gap between sleeve and pipeline. Optimum wire feed speed and torch movement speed was obtained by experiment,which provide reference to welding carbin test.