| 摘要 |
Method to form solid phase plug in pipeline. The method includes a combination of specially designed pig and water handling inside of a pipe. The outside sleeve with labyrinth of pathways to ensure equally distributed flow of cooling liquid or gas over required surface of a line pipe. The applications of a special pig apparatus of the invention drastically shorten time and also quantity of cooling liquid to form solid phase plug. Field of Invention The present invention relates to the apparatus and method to form solid phase plug in combination with fluid media. The pipeline operator may choose this method to isolate segment of pipeline by forming two solid phase plugs of ice spaced apart. Background of the Invention. The technique of forming solid phase plugs for isolation purposes of pipelines using liquid nitrogen as cooling media is known and is described in U.S. patent 4,220,012 dated September 2, 1980. This method employs a chamber placed over the line pipe surface. The chamber is then filled with liquid nitrogen, agitated to induce boiling, increasing heat flow from the line pipe to the evaporating nitrogen. This method uses pipeline fluid or water to form solid phase plug. The time to form solid phase plug using this method is long because plug occupies the full section of line pipe. The time required to freeze the plug is the major issue as it will shorten the time the pipeline is shutdown. In effort to reduce the time to form solid phase plug we bring following solution to this problem.
|
