Method and apparatus for inspecting pipelines from an in-line inspection vehicle using magnetostrictive probes
First Claim
1. A system for the non-destructive evaluation of a pipeline structure comprising:
- a mobile in-line transport vehicle for translational movement through the interior of said pipeline structure;
a linear displacement sensor positioned on said vehicle for generating a signal indicative of said translational movement of said vehicle through the interior of said pipeline structure;
at least one magnetostrictive sensor positioned on said vehicle, said magnetostrictive sensor comprising;
an elongated core, said core having a length much longer than dimensions of its cross-section;
a coil wound around said length of said elongated core; and
means for establishing a bias magnetic field proximate to said elongated core;
wherein said at least one magnetostrictive sensor is positioned on said transport vehicle so as to maintain a generally constant close-spaced position with respect to an inside wall of said pipeline structure as said transport vehicle is moved through the interior of said pipeline structure.
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Accused Products
Abstract
A method and system for implementing magnetostrictive sensor techniques for the nondestructive evaluation of pipeline structures. The system consists of a magnetostrictive sensor instrument unit, a data storage unit, and a plurality of magnetostrictive sensor probes are positioned on an in-line inspection vehicle. The instrumentation unit includes electronics for transmitting excitation pulses to a transmitting magnetostrictive sensor probe as well as electronics for amplifying and conditioning the signals detected by a receiving magnetostrictive sensor probe. The magnetostrictive sensor probes include both plate magnetostrictive sensors and permanent magnets which provide a DC bias magnetic field necessary for magnetostrictive sensor operation. The transmitting and receiving probes are attached to the in-line inspection vehicle by way of mechanical arms on opposing sides of the vehicle. The mechanical arms are spring loaded and are equipped with rollers which maintain the probes at approximately constant distances from the inside diameter of the pipe wall. The method involves generating pulses of shear horizontal waves of frequencies less than 200 kHz. The transmitting magnetostrictive sensor probe generates a wave that propagates in both directions around the circumference of the pipe wall from a point adjacent to the transmitting probe. Both waves are thereafter received at the receiving probe spaced 180 degrees apart from the transmitting probe. Any defect present in the pipe wall within the circumference being investigated will show up in the received signal.
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Citations
17 Claims
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1. A system for the non-destructive evaluation of a pipeline structure comprising:
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a mobile in-line transport vehicle for translational movement through the interior of said pipeline structure;
a linear displacement sensor positioned on said vehicle for generating a signal indicative of said translational movement of said vehicle through the interior of said pipeline structure;
at least one magnetostrictive sensor positioned on said vehicle, said magnetostrictive sensor comprising;
an elongated core, said core having a length much longer than dimensions of its cross-section;
a coil wound around said length of said elongated core; and
means for establishing a bias magnetic field proximate to said elongated core;
wherein said at least one magnetostrictive sensor is positioned on said transport vehicle so as to maintain a generally constant close-spaced position with respect to an inside wall of said pipeline structure as said transport vehicle is moved through the interior of said pipeline structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for the non-destructive evaluation of a pipeline structure comprising the steps of:
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positioning at least one transmitting magnetostrictive sensor adjacent to an inside wall surface of said pipeline structure;
establishing a bias magnetic field adjacent said at least one transmitting magnetostrictive sensor and within a volume of a wall of said pipeline structure;
positioning at least one receiving magnetostrictive sensor adjacent to an inside wall surface of said pipeline structure;
establishing a bias magnetic field adjacent said at least one receiving magnetostrictive sensor and within a volume of a wall of said pipeline structure;
generating a pulsed signal and delivering said pulsed signal to said transmitting magnetostrictive sensor, said transmitting magnetostrictive sensor thereby generating a shear horizontal wave in said wall of said pipeline structure;
receiving said shear horizontal wave and any reflected waves deriving therefrom, at said receiving magnetostrictive sensor, said receiving a magnetostrictive sensor generating a received signal having signal elements characterizing said shear horizontal wave and any reflected waves deriving therefrom; and
identifying anomalous elements within said received signal, said anomalous elements indicative of known and unknown anomalies in said wall of said pipeline, said at least one transmitting and receiving magnetostrictive sensors having an elongated core with a length much longer than dimensions of its cross section and a coil wound around said length of said elongated core. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification