Detection of Corrosion Defects in Buried Pipelines Using Vertically Measured Pipe-To-Soil Potential

  • US 20150204775A1
  • Filed: 01/22/2014
  • Published: 07/23/2015
  • Est. Priority Date: 01/22/2014
  • Status: Active Grant
First Claim
Patent Images

1. A method for measuring the corrosion rate of a corroding site on an underground metal structure buried in soil, the structure being under cathodic protection, comprising:

  • providing an electrical connection to the structure;

    placing a reference electrode in the soil above the structure;

    measuring the structure-to-soil electric potential at a first depth above the structure;

    re-positioning the reference electrode to another depth at the same location above the structure;

    repeating the measuring and re-positioning steps until a data set representing the structure-to-soil potential at various depths to a predetermined depth not reaching the structure is obtained;

    extrapolating the data set to obtain extrapolation data representing the structure-to-soil potential at the surface of the structure under the probe;

    based on the extrapolation data, calculating the gradient of the electrical potential at the surface of the structure under the probe;

    based on the gradient and the conductivity of the soil, calculating current density at the surface of the structure; and

    calculating a corrosion rate from the current density.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×