A joint coating process scheme for submarine pipelines without weight coating

In this paper, the joint coating process used for the production line of pipe laying vessel was studied in order to improve the efficiency of pipe laying vessel method to construct submarine pipelines without weight coating. Firstly, two processes for installing heat shrinkable wraparound sleeve (HSWS) were compared. Then, the workstation layout was optimized by means of computation. In addition, the critical temperature of HSWS to run through the carrier roller was experimentally determined, and the cooling curve after water spraying was investigated. Finally, the process flow of joint coating construction was optimized. It is shown that from the aspect of HSWS installation, dry film process is more suitable than wet film process for the construction of submarine pipelines without weight coating pipeline by the pipe laying vessel method. In order to avoid scuffing the HSWS, the carrier roller between Workstation 7 and Workstation 8 shall be removed. GTS-PE HSWS can run through carrier rollers without damage if its temperature is controlled below 75 ℃. After HSWS is installed, its temperature can satisfy the requirement of running through carrier rollers if it is sprayed with cold water for 10 minutes. The HSWS installation time of one joint coating is decreased to15 minutes by optimizing the construction process.