Method and inspection device for examining the cathodic protection of a ferromagnetic pipeline
AssigneeRosen IP AG
InventorsAndrey Danilov, Ben Bosse, Patrik Rosen
Life of this patent
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Abstract
A method is provided for examining the cathodic protection of a metallic and in particular ferromagnetic pipeline. An inspection device is also provided for examining the cathodic protection of a pipeline, in particular of a ferromagnetic pipeline. The inspection device is formed to be able to pass through the pipeline and in particular be driven by the medium, and includes a magnetizing device serving to create an alternating magnetic field. A magnet unit and a measuring device are provided, and includes at least one magnetic field sensor serving to measure a magnetic field formed on the inner side of the wall of the pipeline.
Claims25
A method for examining a cathodic protection of a ferromagnetic pipeline, the method comprising:
- creating a primary alternating magnetic field and herewith a local change in permeability in a wall of the ferromagnetic pipeline by a magnetizing device of an inspection device moved through the pipeline,
- wherein a secondary direct current (DC) magnetic field is caused by a DC current of cathodic protection being formed in the wall of the ferromagnetic pipeline;
- using a measuring device of the inspection device moved through the ferromagnetic pipeline to measure a resultant magnetic field that emerges from superposition of the primary alternating magnetic field and the secondary DC magnetic field;
- using a computing device to analyze signal components of at least the secondary DC magnetic field giving consideration to the local change in the permeability;
- and
- determining a magnitude of the DC current of the cathodic protection based on the signal components of the secondary DC magnetic field.
An inspection device for examining a cathodic protection of a pipeline, the inspection device being formed to be able to pass through a pipeline, the inspection device comprising:
- a magnetizing device configured to create an alternating magnetic field, the magnetizing device having:
- a measuring device including at least one magnetic field sensor configured to measure a magnetic field formed on an inner side of a wall of the pipeline,
- at least one carrier configured to be rolled through the pipeline in a longitudinal direction thereof in an operational state, the at least one carrier having an at least substantially circular perimeter in a section running transversely to an axis of rotation, and,
- at least two magnet units positioned along the perimeter of the at least one carrier, the at least two magnet units configured to create an alternating magnetic field, magnetic field directions of which run opposite one another,
- wherein the at least two magnetic units are configured such that the magnetic field formed on the inner side of a wall of the pipeline is caused by a DC current of cathodic protection being formed in the wall of the ferromagnetic pipeline.
Dependencies are inferred from the claim text.