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US 5,402,066 AGranted
Method and apparatus for magnetically testing elongate objects using two circumferentially disposed arrays of magnets and two circumferentially disposed arrays of sensors
AssigneeCommercial Technologies, Inc.
InventorsWilliam Hickman, Jr., Joseph P. Dyer
Life of this patent
Estimating the term…
Abstract
A magnetic interferometer for performing nondestructive magnetic induction testing and inspection of wire rope and cable. The device concentrically surrounds a wire rope or cable to be tested and includes means for inducing a magnetic field in the rope or cable as well as means for detecting flux changes in the induced magnetic field. By detecting flux changes in the magnetic field the condition of the rope or cable can be determined.
Claims54
Apparatus for magnetically testing an elongate object, comprising:
- a housing having means for receiving said object;
- first and second magnet means disposed in said housing forming a magnetic field therebetween for passing magnetic flux through said object, said first and second magnet means respectively comprising a plurality of circumferentially disposed magnets approximating a cylindrical magnetic coil having a central cavity for receiving said object, wherein said cavities are longitudinally aligned;
- material of low magnetic permeability separating said first and second magnet means such that said magnetic field forms an open magnetic circuit between said first and second magnet means;
- and
- means for sensing variations in said magnetic flux passing through said object.
2 more elements
Apparatus for magnetically testing an elongate object, comprising:
- a housing having means for receiving said object;
- first and second magnet means disposed in said housing forming a magnetic field therebetween for passing magnetic flux through said object;
- material of low magnetic permeability separating said first and second magnet means such that said magnetic field forms an open magnetic circuit between said first and second magnet means;
- and
- means for sensing variations in said magnetic flux passing through said object comprising first and second circumferentially disposed arrays of sensing elements for receiving said object.
2 more elements
A method for magnetically testing an elongate object, comprising the steps of:
- creating an open magnetic field circuit between first and second magnet means;
- passing said object through said magnetic field for passing magnetic flux through said object;
- sensing variations in said magnetic flux passing through said object at two separate depths within said object;
- generating two separate electric signals from said variations sensed in said sensing step;
- and
- processing said signals to determine the integrity of said object.
3 more elements
Apparatus, comprising:
- first and second magnet housings each comprising a body with a central cavity;
- a plurality of magnets disposed circumferentially within each of said magnet housings to approximate a cylindrical magnetic coil for creating an open magnetic field circuit between said first and second magnet housings;
- sensing means for detecting anomalies in said magnetic field and generating corresponding electrical signals;
- means for processing said electrical signals;
- and
- means for obtaining output from said processed electric signals.
3 more elements
A method for magnetically testing an elongate object, comprising the steps of:
- creating an open magnetic field circuit between first and second magnet means;
- passing said object through said magnetic field for passing magnetic flux through said object;
- generating a first set of electrical signals via a first sensing means disposed a predetermined distance from said object which are responsive to said magnetic flux passing through said object;
- generating a second set of electrical signals via a second sensing means disposed a distance from said object not equal to said predetermined distance which are responsive to said magnetic flux passing through said object;
- processing said signals to determine the integrity of said object.
2 more elements
Apparatus for magnetically testing an elongate object, comprising:
- means for inducing a magnetic field in a portion of said object such that said magnetic field experiences flux changes according to changes in the condition of said portion;
- sensing means for producing electrical signals indicative of said flux changes, said sensing means comprising a housing having a large diameter portion and a reduced-diameter portion, a first array of sensing elements secured to the inner surface of said large-diameter portion, and a second array of sensing elements secured to the inner surface of said reduced-diameter portion, said sensing elements being spaced apart from said object;
- and
- means for processing said electrical signals and obtaining output.
1 more element
Apparatus for magnetically testing an elongate object moving relative to said apparatus, comprising:
- means for inducing a magnetic field in a portion of said object whereby said magnetic field experiences flux changes according to changes in the condition of said portion, said means for inducing a magnetic field comprising first and second magnet housings and a plurality of permanent magnets spaced circumferentially within each of said magnet housings, each of said magnet housings defining a central cavity for receiving said object;
- sensing means disposed between said first and second magnet housings for producing electrical signals indicative of said flux changes, said sensing means comprising:
- a housing defining a central cavity for receiving said object;
- and
- first and second arrays having a plurality of sensing elements supported in said housing in a perpendicular spaced relationship from said object, comprising a conductive rod and a helical wire winding, respectively, said sensing elements arranged circumferentially around said portion of said cable such that said sensing elements of said first array are positioned closer to said object than the sensing elements of said second array, said sensing elements of each of said arrays being electrically connected in series;
- and
- means for supporting said object for relative movement with respect to said inducing means and said sensing means.
4 more elements
Dependencies are inferred from the claim text.