METHOD FOR DETECTING POSITION OF LONGITUDINAL SEAM OF PIPE USING LEAKAGE FLUX PIG

Japanese Patent JP3568084

B2

PROBLEM TO BE SOLVED: To provide a method by which the longitudinal seam of a pipeline can be detected from data collected by means of a leakage flux pig in inspecting the pipeline for soundness and the labor required for the inspection of the pipeline can be reduced, and then, the need of wetting the inside of the pipeline which is required for an ultra sonic pig can be eliminated.
SOLUTION: The data corresponding to leakage magnetic fluxes outputted from each magnetic sensor are collected at prescribed intervals by moving a leakage flux pie on which many magnets and magnetic sensors are arranged correspondingly to the inner periphery of a pipe to be inspected in the axial direction of the pipe and the position of the magnetic sensor corresponding to the data having the smallest leakage magnetic flux is detected as the position of a longitudinal seam by comparing the data at every magnetic sensor. Alternatively, the data corresponding to the leakage magnetic fluxes outputted from each magnetic sensor are collected at prescribed intervals by moving the leakage flux pig on which many magnets and magnetic sensors are arranged correspondingly to the inner periphery of the pipe to be inspected and the position of the magnetic sensor corresponding to the data having the largest dispersion is detected as the position of the longitudinal seam.

Yasushi Yonemura
Tokushige Masuko
Hisao Hotta
Takeichi Suyama

JP35917996A

September 22, 2004

December 30, 1996

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Tokyo Gas Co., Ltd.

G01N27/83; (IPC1-7): G01N27/83

JP8101168A
JP52105885A
JP49015515B1

Yoshikazu Mitsuhashi

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