METHOD AND DEVICE FOR FLAW DETECTION OF INTERNAL PROTECTIVE-INSULATING COATINGS OF PIPELINES Russian patent published in 2019 - IPC F17D5/06 

FIELD: non-destructive testing.

SUBSTANCE: group of inventions relates to diagnostics of technical condition of pipelines, and can be used for flaw detection of inner protective-insulating coatings, in order to avoid uncontrolled opening of protective coatings and damage to pipe wall. Method consists in supply of constant voltage to corresponding electrodes of in-tube instrument by means of built-in voltage source and measurement of current through internal protective-insulating coating of pipeline, occurring on the area limited by two insulating cuffs, tightly fixed on housing of in-pipe instrument. Intra-pipe instrument consists of 3 main elements: measuring section, odometer wheels for measurement of distance traveled, and radio beacon for external monitoring of position of in-pipe instrument. Measuring system of in-tube instrument comprises measuring electrode "A0", as well as electrode "B1" in rear part of in-tube instrument and electrode "B2" in front part, relative to which measurement is made, wherein measuring electrode is connected through low-resistance shunt to measure parameters of current flowing through it. In order to eliminate the effect of electric current leakage in the gap between the insulating cuffs and the inner wall of the inspected pipeline, the in-tube instrument comprises screen electrodes "Ae1" and "Ae2" on both sides of the measuring electrode, having an electrical potential equal thereto.

EFFECT: invention objective is detection of damages of protective-insulating coating of pipeline, which cause leaks of pumped aggressive liquids to steel wall of pipe and its active corrosion destruction.

10 cl, 14 dwg