CATHODIC CORROSION PREVENTION METHOD FOR PIPELINE

摘要

PROBLEM TO BE SOLVED: To provide a cathodic corrosion prevention method for a pipeline, in which a corrosion risk of the pipeline buried to cross a DC electric railway under a crossing part thereof is surely avoided and a cathodic corrosion prevention current is efficiently sent.

SOLUTION: The cathodic corrosion prevention method for the pipeline comprises an advance measurement step of connecting a probe 10 arranged in a sheath pipe C under the crossing part Lc to the pipeline P and measuring a probe current and a probe-on potential simultaneously within a measurement time. An output current of a DC power unit 15 connected to the pipeline P is kept under constant potential control on the basis of the probe-on potential EONto be measured by a control reference electrode 12C while using a high correlation between the probe DC current density IDC, which is calculated by using the measured probe current, and the probe-on potential EONso that the probe DC current density IDCalways passes a cathodic corrosion prevention standard. Otherwise, the output current of the DC power unit 15 connected to the pipeline P is kept under constant current control independently of the probe-on potential EONto be measured by the control reference electrode 12C so that the mean value of the probe DC current density IDCpasses the minimum required probe inflow DC current density of the cathodic corrosion prevention standard.

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