| 摘要 |
<P>PROBLEM TO BE SOLVED: To evade the risk of a d.c. stray current corrosion with respect to a high resistivity coated pipeline locally influenced by d.c. stray current while maintaining satisfactory cathode corrosion prevention conditions. <P>SOLUTION: A pipeline 1 which is laid in an electrolyte and in which the surface of a metal body is covered with high resistivity coating is used as the object for corrosion prevention, the connection part of the pipeline 1 apart by a set distance R from a spot S on the pipeline 1 locally influenced by d.c. stray current is provided with an insulation joint 2. A plurality of sacrificial anodes 3, 4, 5 different in ground resistance at each connection part is connected to the metal body of the pipeline 1 from the insulation joint 2 to the spot S in such a manner that the ground resistance is lowest at the connection part in the vicinity of the insulation joint 2, and, at the plurality of connection parts provided at prescribed intervals from the connection part in the vicinity thereof, the ground resistance is gradually increased, and the sacrificial anodes are not connected to the vicinity of the spot S. <P>COPYRIGHT: (C)2008,JPO&INPIT |
