| 摘要 |
<PICT:0984477/C6-C7/1> An electrode for electrolytically protecting a metal part, particularly of cast iron water boxes of heat exchangers, in contact with an electrolyte solution such as sea water comprises a rod consisting of or having an outer covering of a metal resistant to the solution under electrolytic conditions encased over at least most of its length in a perforated or porous plastic sheath. As shown, a part of the wall 1 of a cast iron water box may be cathodically protected by attaching an anode to the inner side on saddles 2. The anode preferably consists of a 1/4 inch diameter copper-cored titanium rod 3 provided with a thin outer coating of platinum, which may be continuous or discontinuous, and encased in a sheath 4 of plastic, e.g. P.V.C., punched with perforations 5; alternatively an expanded polypropylene mesh tube may be used. A terminal, consisting of a titanium lug 6 and cap 7 fitting over one end of the rod 3 and crimped thereon to form a good electrical connection and to seal the exposed copper core against contact with the solution, is connected to positive pole of a D.C. source by means of a threaded rod 8, passing through and insulated from the wall 1 e.g. using P.T.F.E. bushes 10, 11 and neoprene and nylon washers 16, 17 and 18, 19 respectively, and titanium nuts 14, 15 and 21. The above anodes may also be mounted on a ships' hull or the inner walls of fresh water tanks. Alternatively, for anodic protection of stainless steel or titanium in an acid solution, the electrode is used as a cathode. |
