Abstract
現場製作一深井陽極地床 (100公尺深)，測試不同深度下之陽極放電時， 對長途管線之保護效果，另外分別以理論及實驗以了解陰極防蝕之迴路電 阻。重要結論如下： (1) 不同深度之陽極對於長途管線之保護效果，以 極化量判定時，其管線距離陽極地床愈遠時，保護效果依指數變化而減小 。 (2) 以理論判斷陰極防蝕迴路電阻中之電解質電阻（土壤電阻），可 忽略不計，並以現場試驗證明之。於現場之深井陽極地床，測試不同深度 之陽極接地電阻及不同深度組合之陽極接地電阻，並提出一適合現場之陽 極地床接地公式。結論如下： (1) 深井陽極地床接地電阻之計算，不能 依單一陽極計算，除非是於陽極套管及填充料未被破壞之前，否則誤差極 大。 (2) 深井陽亟地床接地電阻為 1──────── (㏑(8L/d) - 1 + 2L/S×㏑0.656n) nΣ 1/ρ_n×2πL 1並已由實驗證明。 The potential decay from the anode bed along the pipeline can be predicted from formula reported elsewhere for conventional shallow groundbed system (surface type remote groundbed), but in the deepwell groundbed system, few data are available. The resistance of the entire cathodic protection current circuit is discussed theoretically and the potential change for the deep well groundbed system of the applied current cathodic protection method along the pipeline for the anode in different soil depths of soil are also derived from the field tests. Equations for the calculation of the resistance of the conventional surface- type ground bed with single anode and multi-anodes have been discussed in many papers. For deep well ground bed system, the resistance of a single vertical anode can be calculated by using the Dwight equation[1]. But this is not applicable to all cases, especially to the old system of deep well groundbed. In this paper data from field test were presented, also a novel equation was introduced and proved to be effective in the calculation of the deep well ground bed resistance. In this study the cause that leads to the damage of the condenser tube made of copper-nickel alloy is analyzed. The corrosion behavior and the possible ways of corrosion prevention of copper-nickel alloy in sulfur- contaminated seawater is discussed.