Improvements in electrode structures

摘要

893,015. Anodes for preventing corrosion. READER & SONS Ltd., E. June 1, 1960 [June 2, 1959], No. 18786/59. Class 123(1). An impressed-current cathodic protection electrode comprising an electrode proper 4 has firmly attached to its lower end a porous ceramic part 3 which is less conductive to electrical currents than the electrode proper and is adapted to retain, at least temporarily, a film on diffusion of liquid after immersion in and withdrawal from such liquid so that, when the electrode is positioned with the part 3 immersed in an electrically conductive liquid and the level of the liquid is lowered, the electrical resistance to the current flow between the electrode proper and the liquid progressively increases as the liquid level is lowered and the liquidretained by the part 3 leaks away. In this manner the potential across the gap between the collar 3 and the liquid surface is insufficient to cause a spark when the liquid eventually drops below the level of the part 3. In a modification, Fig. 2, the electrode proper comprises a film of platinum 8 over the part of a titanium rod 6 which extends above a lower collar 7 which is adapted to retain a thin layer of liquid upon its upper surface when the liquid falls below the platinum part 8.