METHOD OF CORROSION CROSS-MONITORING OF UNDERGROUND METAL STRUCTURES Russian patent published in 2000 - IPC

FIELD: civil engineering. SUBSTANCE: method is used for corrosion protection of underground pipelines. Structure pipeline is divided into sections, cathode- protection current is frequency-modulated, waveforms of structure-ground potential and current is frequency-modulated, waveforms of structure-ground potential and current in structure are recorded at beginning and end of section. Then accumulated date are transmitted to load-dispatching centre, amplitude- phase-frequency characteristics sections and degree of degradation of section insulating coating are determined by variation of those characteristics. Modulation may be performed alternately in initial and end section s of structure, as well as by interruption of cathode-protection current with recording of transient pulse characteristics. EFFECT: enhanced reliability of pipelines. 3 cl, 4 dwg