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US 4,228,399 AGranted
Offshore pipeline electrical survey method and apparatus
AssigneeHarco Corporation
InventorsFrank E. Rizzo, Marvin L. Miller, Clark Weldon
Life of this patent
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AssigneeHarco Corporation
InventorsFrank E. Rizzo, Marvin L. Miller, Clark Weldon
Estimating the term…
A method and apparatus for conducting offshore pipeline electrical surveys is characterized by initially locating and marking the pipeline, traversing the length of the pipeline towing a reference electrode in close proximity to the structure, providing a supply of wire having one end electrically and mechanically connected to the pipeline at a reference location, playing out the wire along the length of the pipeline through a distance measuring device while transporting the supply of wire and towing the reference electrode, and measuring and recording the potential difference between the reference electrode and pipe either continuously or at spaced test locations along the length of the structure. The method and apparatus are further characterized by alternately connecting and disconnecting an electrical power source to the pipeline at the reference location, measuring and recording the potential difference in both connected and disconnected modes at the test locations, and measuring and recording the depolarization and/or polarization times when the power source is disconnected and/or connected, respectively, to the pipeline.
An apparatus for making offshore structure electrical surveys comprising reference electrode means in the environment proximate the structure, transport means to carry said reference electrode means along the length of the structure in close proximity to the structure, said transport means including a boat and said reference electrode means being towed behind said boat, a supply of flexible, small gauge, disposable elongate electrically conductive insulated magnet wire means carried by said boat for electrically and mechanically connecting the apparatus with the structure at a reference location thereon, meter means electrically connected to said wire means and electrode means for indicating the potential difference between said reference electrode means and said electrically conductive magnet wire means, and means driven by said electrically conductive magnet wire means for measuring the length of said electrically conductive magnet wire means as it is played out from the apparatus as it is carried by said transport means whereby the structure-to-environment potential difference may be determined at measured distances along the length of the structure.
A method for making offshore structure electrical surveys comprising the steps of:
Dependencies are inferred from the claim text.