Cathodic protection of underwater pipelines - where protective electric current applied to pipes is measured by immersed reference electrode

摘要

A holder is used to attach a polymer tube (2) to the pipeline. Tube (2) is open at one end, and contains a sealing ring (3) locating a Cu/CuSO4 reference electrode (1) inside tube (2), so the diaphragm (4) on the electrode is near the open end of tube (2). Ring (3) forms an annulus between the electrode (1) and the bore of tube (2); and the annulus is filled with a cast synthetic resin mass. Electrode (1) is connected via a cable to a meter located on a river bank or above the water. Part of the electrode diaphragm (4) may be covered with the cast synthetic resin mass to increase the working life of the electrode. Used esp. on a large dia. drain or sewer pipes; or on pipelines carrying gas or oil.