Apparatus for electromagnetically testing the walls of pipelines
First Claim
1. Apparatus for electromagnetically testing pipeline walls of ferromagnetic material comprising structure means movably supported on the inside walls of the pipeline such that said structure means is moveable longitudinally along the inside of the pipeline, speed control means on said structure means for controlling the speed of movement of said structural means through said pipeline, first and second magnetic means carried by said structure means for detecting cracks and flaws in said pipeline as said structure means moves longitudinally in said pipeline, said first magnetic means providing one magnetic field operable to detect cracks and flaws extending generally in one direction, said second magnetic means providing a magnetic field operable to detect cracks and flaws extending generally transversely to said one direction, said first and second magnetic means being spaced from one another, and electrodynamic ultrasonic means carried by one of said first and second magnetic means for simulaneously measuring the thickness of the pipeline wall, said electrodynamic ultrasonic means comprising at least one high-frequency current coil substantially aligned with the pipeline wall to transmit and/or receive pulses in the ultrasonic range and which are inductively coupled to the pipeline wall, said at least one current coil having a measuring means for measuring delays between the transmitted and received pulses, whereby the apparatus simultaneously detects cracks and flaws extending both in said one direction and in said other direction and also simultaneously measures the pipeline wall thickness as the structure means continuously moves longitudinally within the pipeline.
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Abstract
Apparatus for electromagnetically testing pipeline walls of steel or the like ferromagnetic material which is equipped, for example with a magnetizing coil for leakage-flux measurements, can be extended for ultrasonic measurement which is inductively excited and inductively measured with regard to the travel time as far as a reflecting surface and back, in the disposed in one or more of the pole regions there is a high-frequency current coil for the transmission and/or reception of steep-edged waves which are inductively coupled at the wall of the pipeline. The associated method starts from a stationary magnetic field in which high-frequency current pulses are produced in order to initiate vibrations in the pipe wall through induced currents. The travel time of these vibrations to a reflecting point and back can be measured in order to obtain an indication regarding the intact thickness of the pipe wall.
75 Citations
36 Claims
- 1. Apparatus for electromagnetically testing pipeline walls of ferromagnetic material comprising structure means movably supported on the inside walls of the pipeline such that said structure means is moveable longitudinally along the inside of the pipeline, speed control means on said structure means for controlling the speed of movement of said structural means through said pipeline, first and second magnetic means carried by said structure means for detecting cracks and flaws in said pipeline as said structure means moves longitudinally in said pipeline, said first magnetic means providing one magnetic field operable to detect cracks and flaws extending generally in one direction, said second magnetic means providing a magnetic field operable to detect cracks and flaws extending generally transversely to said one direction, said first and second magnetic means being spaced from one another, and electrodynamic ultrasonic means carried by one of said first and second magnetic means for simulaneously measuring the thickness of the pipeline wall, said electrodynamic ultrasonic means comprising at least one high-frequency current coil substantially aligned with the pipeline wall to transmit and/or receive pulses in the ultrasonic range and which are inductively coupled to the pipeline wall, said at least one current coil having a measuring means for measuring delays between the transmitted and received pulses, whereby the apparatus simultaneously detects cracks and flaws extending both in said one direction and in said other direction and also simultaneously measures the pipeline wall thickness as the structure means continuously moves longitudinally within the pipeline.
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36. Apparatus for electromagnetically testing pipeline walls of ferromagnetic material comprising structure means movably supported on the inside walls of the pipeline such that said structure means is moveable longitudinally along the inside of the pipeline, speed control means on said structure means for controlling the speed of movement of said structural means through said pipeline, first and second magnetic means carried by said structure means for detecting cracks and flaws in said pipeline as said structure means moves longitudinal in said pipeline, said first magnetic means providing one magnetic field operable to detect cracks and flaws extending generally in one direction, said second magnetic means providing another magnetic field operable to detect cracks and flaws extending generally transversely to said one direction, said first and second magnetic means being spaced from one another, and electrodynamic ultrasonic means carried by one of said first and second magnetic means for simultaneously measuring the thickness of the pipeline wall, said structure means comprises bearing means for rotatably supporting said one magnetic means, said bearing means having a bearing axis generally coincident with the longitudinal axis of the pipeline such that said one magnetic means rotates about said bearing axis as said structure means moves along said pipeline, said one magnetic means thereby moving along a helical path as said structure means moves along said pipeline, said one magnetic means comprises a magnetizing coil means and at least two pole means such that the pipeline wall is included in a magnetic circuit between said at least two pole means, said electrodynamic ultrasonic means further comprising at least one high-frequency current coil juxtaposed to at least one of said pole means and substantially aligned with the pipeline wall to transmit and/or receive pulses in the ultrasonic range and which are inductively coupled to the pipeline wall, said at least one current coil having a measuring means for measuring delays between the transmitted and received pulses, whereby the apparatus simultaneously detects cracks and flaws extending both in said one direction and in said other direction and also simultaneously measures the pipeline wall thickness as the structure means continuously moves longitudinally within the pipeline.
Specification