Method and apparatus for special end area inspection

A magnetic inspection station for tubular members and methods for operating the same have a longitudinal flaw detection assembly adapted to pass a circumferential magnetic field through a tubular member and a transverse flaw detection assembly adapted to pass a longitudinal magnetic field through the tubular member. The magnetic fields cause congregation of a ferromagnetic particles sprayed on the tubular member in a magnetic particle inspection fluid. The congregation of ferromagnetic particles indicates a flaw in the tubular member. The magnetic inspection station includes a clamping apparatus positioned closely adjacent to the magnetic inspection station and adapted to support the tubular member within the magnetic inspection station and exert a compensating force on the tubular member to resist the magnetic forces generated by the longitudinal flaw detection assembly and the transverse flaw detection assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a method and apparatus for inspecting tubular members and, in particular, to an apparatus and method for inspecting tubular couplers and tubular member ends.

2. Brief Description of Related Art

Tubular members are often inspected by passing magnetic fields through the tubular member. Where a flaw is found in a wall of the tubular member, the magnetic field will deviate causing magnetic flux to leak from the surface of the tubular member. A suspension containing ferromagnetic particles visible to the human eye under appropriate conditions is sprayed on the tubular member while the tubular member rotates within the magnetic field. Deviation of the magnetic field and flux leakage cause a congregation of ferromagnetic particles disposed on the surface of the tubular member at the site of the deviation of the magnetic field. The location of the congregation may be marked to identify the flaw in the tubular member. This process may cause an undesirable residual magnetization of the tubular member.

When inspecting the end areas of tubular members or short coupler tubular members, the short length of the end or coupler may cause deviation of the magnetic field and end flux leakage that is unrelated to a flaw in the end or coupler. These deviations and end flux leakage will appear as tubular member flaws. Thus, a special apparatus is needed to closely control the passage of the magnetic field through the tubular member when inspecting the ends of a tubular member or a tubular coupler. These special apparatuses are adapted to inspect only the ends of a tubular member and are positioned in a manner that may cause the end portion of the tubular member to be pulled into contact with the apparatus when the magnetic field is passed through the tubular member. Therefore, there is a need for an inspection apparatus that inspects tubular member ends and couplers without leaving the tubular member magnetized and does not face the risk of damage caused by contact between the tubular member and the apparatus.

SUMMARY OF THE INVENTION

These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present invention that provide an apparatus for ends area inspection of a tubular member, inspection of tubular couplers, and methods for inspecting the same.

In accordance with an embodiment of the present invention, a magnetic inspection system to inspect test tubular member ends and couplers is disclosed. The magnetic inspection system includes a longitudinal flaw detection assembly (LFDA) that generates a magnetic field that passes circumferentially through the end of the tubular member, and a transverse flaw detection assembly (TFDA) that generates a magnetic field that passes longitudinally through the end of the tubular member. The magnetic inspection system also includes an inspection station frame assembly positioned on a substantially planar horizontal surface. The LFDA and the TFDA are mounted to the inspection station frame assembly so that the LFDA and the TFDA are spaced-apart from the substantially planar horizontal surface. The LFDA and the TFDA are positioned on the inspection station frame assembly so that the end of the tubular member is positioned in both the LFDA and the TFDA. The magnetic inspection system also includes a magnetic particle inspection (MPI) insertion apparatus adapted to coat the tubular member in an MPI fluid. The MPI fluid has a plurality of ferromagnetic particles suspended therein, the ferromagnetic particles appearing fluorescent when exposed to an ultraviolet light. The magnetic inspection system further includes an ultraviolet light assembly that is adapted to expose an exterior surface of the tubular member to ultraviolet light and an interior surface of the tubular member to ultraviolet light. The magnetic inspection system includes a tubular member clamping apparatus positioned closely adjacent to and separate from the inspection station frame assembly. The tubular member clamping apparatus is adapted to support the tubular member within the LFDA and the TFDA, rotate the tubular member within the LFDA and the TFDA about an axis of the tubular member. The axis is substantially parallel to the substantially planar horizontal surface. The tubular member clamping apparatus exerts a compensating force on the tubular member that resists the magnetic forces of the LFDA exerted on the tubular member during inspection of the tubular member.

In accordance with another embodiment of the present invention, a magnetic inspection system to insect test tubular member ends and couplers is disclosed. The magnetic inspection system includes a longitudinal flaw detection assembly LFDA that generates a magnetic field that passes circumferentially through the end of the tubular member, and a transverse flaw detection assembly (TFDA) that generates a magnetic field that passes longitudinally through the end of the tubular member. The magnetic inspection system also includes an inspection station frame assembly positioned on a substantially planar horizontal surface. The LFDA and the TFDA are mounted to the inspection station frame assembly so that the LFDA and the TFDA are spaced-apart from the substantially planar horizontal surface. The LFDA and the TFDA are positioned on the inspection station frame assembly so that the end of the tubular member is positioned in both the LFDA and the TFDA. The magnetic inspection system also includes a magnetic particle inspection (MPI) insertion apparatus adapted to coat the tubular member in an MPI fluid. The MPI fluid has a plurality of ferromagnetic particles suspended therein the ferromagnetic particles appearing fluorescent when exposed to an ultraviolet light. The magnetic inspection system further includes an ultraviolet light assembly that is adapted to expose an exterior surface of the tubular member to ultraviolet light and an interior surface of the tubular member to ultraviolet light. The magnetic inspection system includes a tubular member clamping apparatus positioned closely adjacent to and separate from the inspection station frame assembly. The tubular member clamping apparatus is adapted to support the tubular member within the LFDA and the TFDA, rotate the tubular member within the LFDA and the TFDA about an axis of the tubular member. The axis is substantially parallel to the substantially planar horizontal surface. The tubular member clamping apparatus exerts a compensating force on the tubular member that resists the magnetic forces of the LFDA exerted on the tubular member during inspection of the tubular member. The tubular member clamping apparatus includes a vertical support beam mounted to the substantially horizontal surface, and a first and second compensating piston assembly each having lower ends mounted to opposite sides of the vertical support beam. Pivotable rollers mount on ends of the respective compensating piston assemblies opposite the vertical support beam. The pivotable rollers support the tubular member. A clamping piston assembly is coupled to a motorized roller to clamp the tubular member between the pivotable rollers and the clamping piston while rotating the tubular member. When the LFDA exerts a magnetic force on the tubular member pulling the tubular member toward a pole of the LFDA, the compensating pistons exert reactive forces on the tubular member to push one or more of the pivotable rollers into tighter contact with the tubular member.

In accordance with yet another embodiment of the present invention, a method for inspecting tubular members is disclosed. The method inserts a tubular member into a longitudinal flaw detection apparatus (LFDA) and a transverse flaw detection apparatus (TFDA). The tubular member is supported by a clamping apparatus adapted to rotate the tubular member on an axis of the tubular member. The method rotates the tubular member with a motorized roller of the clamping apparatus, and passes a magnetic field generated by the LFDA circumferentially through the tubular member while spraying the interior and exterior of the tubular member with a magnetic particle inspection (MPI) fluid having a plurality of ferromagnetic particles that appear fluorescent when exposed to ultraviolet light. The method exposes the interior and exterior of the tubular member to ultraviolet light and identifies areas of congregated MPI in response to the circumferential passage of the magnetic field. The method also passes a magnetic field generated by the TFDA longitudinally through the tubular member while spraying the interior and exterior of the tubular member with the MPI fluid. The method exposes the interior and exterior of the tubular member to ultraviolet light and identifying areas of congregated MPI in response to the longitudinal passage of the magnetic field. In response to generation of magnetic forces by the magnetic fields, the method exerts a counteracting force on the tubular member with the clamping apparatus to prevent contact between the tubular member and the LFDA and the TFDA.

An advantage of the disclosed embodiments is that they provide a magnetic inspection assembly that may inspect the ends of a tubular member or a tubular coupler. In addition, the disclosed embodiments provide an inspection apparatus that does not leave the tubular member or coupler magnetized following the inspection process. Still further, the disclosed embodiments provide an apparatus that prevents contact between the tubular member and the inspection apparatus during the inspection process, thereby preventing damage to the ends area and the inspection apparatus during the inspection process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. Additionally, for the most part, details concerning power controls, station structural framework, and the like have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the skills of persons skilled in the relevant art.

FIG. 1illustrates an exemplary embodiment of an inspection station11for inspecting pipe couplers and pipe ends and detecting anomalies. Inspection station11includes a first conveyor13, a lifting apparatus15, a longitudinal flaw detection apparatus (LFDA)17, a transverse flaw detection apparatus (TFDA)19, and a second conveyor21. Inspection station11ofFIG. 1also includes structural and control components necessary to orient and operate the illustrated components as depicted (not shown). Any number of suitable alternatives exist to provide suitable support and operational control of the inventive components described below. A person skilled in the art will understand that all structural components necessary to position and operate the illustrated components are contemplated and included by the described embodiments.

First and second conveyor13,21each include conveyor belts configured to bring a coupler23, or a pipe end (not shown), proximate to lifting apparatus15prior to inspection and away from lifting apparatus15following inspection. Coupler23may be a tubular or annular member for coupling or joining to separate tubular members. As shown, first and second conveyors13,21are aligned substantially axially with lifting apparatus15. Lifting apparatus15is configured to receive coupler23from conveyor13and lift coupler23into an appropriate position for inspection of coupler23, i.e. positioned within one or more magnetic fields as described in more detail below. Lifting apparatus15is further configured to lower coupler23following inspection for removal of coupler23from inspection station11by conveyor21. LFDA17is configured to pass a circumferential magnetic field through coupler23to inspect coupler23for longitudinal flaws in coupler23. Longitudinal flaws include anomalies in the inspected tubular member that run lengthwise within the tubular member. TFDA19is configured to pass a longitudinal magnetic field through coupler23to inspect coupler23for transverse flaws. Transverse flaws refer to anomalies in the inspected tubular member that run circumferentially within the tubular member. Both longitudinal flaws and transverse flaws may include inclusions, seams, plugs, and the like, and can range in size from barely detectable to the naked eye to up to 2-3 inches in length. Generally, longitudinal and transverse flaws will appear as tight cracks having a width that is barely perceptible.

Referring toFIG. 2, lifting apparatus15includes a lift plate25, lifts27, roller mounting brackets29, and rollers31. In the illustrated embodiment, two lifts27couple to lift plate25. A person skilled in the art will understand that more or fewer lifts27may be used as needed. Lifts27further couple to an inspection station frame (not shown) and are configured to raise and lower coupler23relative to LFRD17from a lower position, shown inFIG. 1andFIG. 3, to an upper position, shown inFIG. 2. When in the upper position, the exterior surface of coupler23will engage a motorized roller49during inspection of coupler23. Lifts27may include linear bearing lifts, screw lifts, hydraulic lifts, or the like. In an exemplary embodiment, lifts27are automatically operated based on expected operational timing or alternatively based on sensors (not shown) indicating that a coupler or pipe end is positioned and ready to be lifted. Alternatively, lifts27may be manually operated. As shown inFIG. 1, each lift27includes a rail28adapted to be mounted to a body, substantially vertical surface, or the like having sufficient strength to bear the weight of the of lifting apparatus15and coupler23. Each lift27may also include a bearing30adapted to mount lift plate25to each rail28. Bearings30may be motorized to provide locomotive action for lifting apparatus15. In other embodiments, an external lift may be mounted to bearings30or lift plate25to provide the necessary force to lift lifting apparatus15.

Lift plate25ofFIG. 2is a plate configured to mount lifts27and roller mounting brackets29. In the exemplary embodiment, lift plate25is a planar member substantially normal to an axis of coupler23. As shown inFIG. 2, lift plate25defines an opening33configured to allow passage of coupler23through lift plate25. Opening33extends inward from an upper edge of lift plate25. In the illustrated embodiment, opening33has a width substantially greater than the diameter of coupler23, and a rounded lower end. A person skilled in the art will understand that opening33may vary in size and shape as needed to permit passage of coupler through lift plate25from first conveyor13. Lift plate25further defines upper mounting holes35, and a plurality of lower mounting holes37. Roller mounting brackets29include suitably shaped brackets configured to position rollers31to lift and bear the weight of coupler23during inspection. As shown, roller mounting brackets29position rollers31so that a distance between rollers31is less than a diameter of coupler23. In an exemplary embodiment, when conveyor13moves coupler23on a carrier24proximate to rollers31, rollers31will engage an exterior surface of coupler23. Lifts27will actuate to raise lift plate25vertically raising the coupled roller mounting brackets29and rollers31vertically. When lift plate25moves to the upper position shown inFIG. 2, rollers31will bear the weight of coupler23without also lifting carrier24. Furthermore, when lifting apparatus15raises coupler23to the upper position ofFIG. 2, a gap between the exterior diameter surface of coupler23and an adjacent end of extenders39of LFDA17is minimized. In an exemplary embodiment, this gap is approximately ¼″ or more.

In the illustrated embodiment, roller mounting brackets29each have a lower member41(FIG. 3) and an upper member43(FIG. 3). Lower member41and upper member43join at interior ends proximate to a horizontal axis45passing through a center of opening33so that each roller mounting bracket29has L-like shaped with a declined upper leg. A lower end of lower member41couples to lift plate25with fasteners (not shown) that insert through lower mounting holes37in lower member41and plate25where holes37extend generally parallel with axis45. Lower mounting holes37include pre-formed holes positioned such that inspection station11may be adjusted to accommodate for various coupler and pipe diameter sizes. Each lower mounting hole37corresponds to a particular diameter range of pipe sizes such that when lower member41couples to a particular lower mounting hole37, rollers31will be positioned to lift that particular range of coupler sizes from a carrier into the upper position to be inspected. An upper end of upper member43(FIG. 3) couples to lift plate25with fasteners (not shown) that insert through upper mounting holes35in upper member43and lift plate25.

Rollers31couple to roller mounting brackets29at an end of rollers31proximate to lift plate25. Rollers31ofFIG. 2are rotational elements configured to support the weight of coupler23while allowing rollers31to rotate about an axis47passing through a center of each roller31. Rollers31are free spinning rollers configured to allow coupler23to rotate on rollers31when the coupler23is rotated by motorized roller49.

In the example ofFIG. 2, motorized roller49is a roller having a cylinder like configuration that is coupled to an internal or external motor (not shown). The motor rotates motorized roller49that in turn drives cylindrical or spherical member(s) frictionally engaged to the exterior surface of motorized roller49. Motorized roller49couples to the inspection station frame (not shown) such that, during inspection of coupler23, an exterior surface of motorized roller49will engage the exterior surface of coupler23, transferring rotational motion of motorized roller49to coupler23, thereby rotating coupler23. The contact force between the exterior surface of motorized roller49and coupler23when coupler23is in the upper position will be sufficient to overcome any loss of friction between the surfaces caused by wetting of either or both surfaces. Motorized roller49may be positioned with an air spring to prevent undesired movement of motorized roller49during inspection of coupler23. Similar to roller mounting brackets29, motorized roller49may be adjusted to accommodate different pipe sizes.

Still referring toFIG. 2, LFDA17includes a yoke having coils51, side circuit elements53, upper circuit elements54, base circuit element55, and moveable rails57. Optionally, LFDA17may include extenders39. Side, upper, and base circuit elements53,54,55include a low retentivity iron. As illustrated inFIG. 2, lower ends of side elements53perpendicularly join base element55at opposing ends of base element55. Upper ends of side elements53perpendicularly join ends of upper circuit elements54; this embodiment positions upper circuit elements54over base circuit element55. As shown, side circuit elements53, upper circuit elements54, and base circuit element55have a generally rectangular profile. A person skilled in the art will understand that side circuit elements53, upper circuit elements54, and base circuit element55may have any suitable profile, such as a cylindrical or triangular profile, provided elements53,54and55operate as described herein. Non-joined ends of upper circuit elements54are shown separated by a gap56. The gap56may be approximately equal to the exterior diameter of coupler23. In an exemplary embodiment, when coupler23is raised into the upper position, coupler23can substantially fill gap56. In one example, a ¼″ gap exists between the end of each upper circuit element54end and the exterior surface of coupler23. Optionally, the gaps between opposite ends of upper circuit elements54and the exterior diameter surface of coupler23are equal. Extenders39may be coupled to ends of upper circuit element54to close narrow gap56to the appropriate distance.

Coils51include wire coils wound around side circuit elements53. Coils51may be coupled to a DC power supply (not shown), such as a Sorensen XFR Series, Xantrex Technology XFR300-9 series, or the like. Current from the power supply to coils51can induce a magnetic field in circuit elements53,54,55which are magnetically coupled to coils51. When coupler23is lifted to the upper position filling gap56, the magnetic field completes a magnetic circuit through coupler23by passing circumferentially through a wall of coupler23. In an exemplary embodiment, coils51each include 100 turns of wire in each coil sized such that, when powered, coils51produce approximately 5,000 ampere turns of magnetic motive force. In another exemplary embodiment, coils51each include approximately 2500 turns of wire in each coil sized such that, when powered, coils51produce approximately 10,000 ampere turns of magnetic motive force.

Moveable rails57couple to base circuit element55through suitable bearings and further couple to the inspection station frame or a substantially planar horizontal surface58. Moveable rails57are configured to move ends of upper circuit elements54horizontally the length of coupler23during inspection, exposing the entire length of coupler23to the circumferential magnetic field produced by LFDA17. Moveable rails57may include hydraulically actuated pistons, screw type devices, linear bearing devices, or the like that are actuable to move the base circuit element55, and the coupled side and upper circuit elements53,54along the length of rails57. Movement of LFDA17along rails57may be controlled based on expected inspection process time, sensors (not shown) located within inspection station11, or by manual operation.

Continuing to refer toFIGS. 2 and 3, TFDA19includes an electromagnetic ring59coaxial with axis45. Electromagnetic ring59has a wire coil (not shown) wound coaxial with axis45within a housing60. The wire coil of electromagnetic ring59couples to a DC power supply (not shown). The DC power supply, such as a Sorensen XFR Series, Xantrex Technology XFR300-9 series, or the like, is configured to supply a current to the wire coil of electromagnetic ring59inducing a magnetic field configured to pass longitudinally through coupler23during inspection. In addition, electromagnetic ring59may produce approximately 5,000-10,000 ampere turns of magnetic motive force. In alternative embodiments, electromagnetic ring59will be hinged and offset from axis45such that electromagnetic ring59may variably move radially closer to and away from coupler23.

The power supplies to LFDA17and TFDA19may be one unit configured to alternately power LFDA17and TFDA19. Alternatively, the power supplies to LFDA17and TFDA19may comprise multiple units configured to variably operate to power LDFA17and TFDA19. A person skilled in the art will understand that any suitable electrical configuration capable of supplying power to LFDA17and TFDA19in the manner described below are contemplated and included in the disclosed embodiments.

Housing60ofFIG. 2couples to base circuit element55by ring couplers61. In the illustrated embodiments, ring couplers61are cylindrical members that are mounted within corresponding bores formed in base circuit element55. Housing60may be secured to upper portions of ring couplers61by any suitable manner, such as by welding, fasteners or the like. A person skilled in the art will understand that housing60may be secured to base circuit element55by any suitable manner and some embodiments may not use ring couplers61. Similar to LFDA17, TFDA19may move along rails57such that the entire length of coupler23will pass through an interior of electromagnetic ring59during inspection of coupler23. This allows the entirety of coupler23to be exposed to the magnetic field at the same intensity at some point during an inspection process described below.

Still referring toFIG. 2, a spray bar63is shown positioned, in any suitable manner, proximate to motorized roller63. Spray bar63includes an apparatus connected to a fluid circulation system and configured to spray a fluid onto an exterior surface of coupler23during inspection. Spray bar63may be coupled to the inspection frame, or alternatively positioned by an operator of inspection station11. The fluid passed through spray bar63and onto the surface of coupler23includes a magnetic particle inspection material (MPI) mixed with water or other fluids as needed. In an example, the MPI includes a ferrous powder coated with a fluorescing substance. In natural light, the MPI is not discernable to the naked eye within the fluid; however, when exposed to an ultraviolet light, the MPI fluoresces and is visible to the naked eye. Inspection station11may include a sump (not shown) positioned beneath rollers31and configured to collect and re-circulate the MPI fluid passing through spray bar63. In addition, an operator may have a handheld spray device that is moveable to spray an interior of coupler23with the MPI fluid. A person skilled in the art will understand that the MPI may be used without an associated fluid.

At least one ultraviolet light source65may be positioned to expose the exterior surface of coupler23to an ultraviolet light during inspection. Ultraviolet light source65may couple to the inspection frame (not shown) or alternatively may be handheld. In addition, an operator may have a handheld ultra violet light that is moveable to expose the interior of coupler23to ultraviolet light.

In one non-limiting example of operation of an inspection process, the conveyor13moves coupler23proximate to lifting apparatus15as shown inFIG. 1. Lifting apparatus15is in the lower position as shownFIG. 1andFIG. 3. Conveyor13moves coupler23until coupler23is positioned over rollers31. Lifting apparatus15lifts coupler23on rollers31so the exterior surface of coupler23engages motorized roller49as shown inFIG. 2andFIG. 4. The motor coupled to motorized roller49rotates motorized roller49, and the frictional contact between motorized roller49and coupler23rotates coupler23in rollers31with rotation of motorized roller49. Coupler23continues to rotate throughout the entire inspection process. An operator may optionally turn on spray bar63to maintain the MPI fluid spray on the exterior surface of coupler23with the MPI fluid for the duration of the inspection process. Alternatively, spray bar63may operate continuously while inspection station11is operated.

LFDA17is powered and a current is applied to coils51. This may occur automatically, or alternatively in response to input from an operator. The current passing through coils51induces a magnetic field in circuit elements53,54, and55. As shown inFIG. 5, the magnetic flux lines67represent a magnetic field completing a magnetic circuit by passing from one extender39circumferentially around the wall of coupler23and into the other extender39. LFDA17moves the length of coupler23along rails57, as shown inFIG. 4A, while coupler23continues to rotate, subjecting the entire wall of coupler23to the magnetic circuit.

An operator may visually monitor the surface of coupler23. In an example, at areas where coupler23is free of flaws, flux lines67will pass through coupler23relatively uniformly, as shown by flux lines67passing through the lower half of coupler23inFIG. 5. In an example, at areas where coupler23has a flaw or anomaly perpendicular to the circumferential magnetic field represented by flux lines67, the permeability, the measure of how easily magnetic flux passes through a material, of coupler23will change, causing magnetic flux67to leak out of the surface of coupler23as shown at leak69. Leak69may be an area where a flaw in coupler23forces flux lines67to breach the surface of coupler23. At these areas, the magnetic field will exert a magnetic force on the MPI of the MPI fluid, congregating the MPI at the anomaly and conforming it to the shape of the leak caused by the flaw. Typically, this will be the same approximate size and shape as the flaw. The ultraviolet light65shined on the exterior surface of coupler23will illuminate a congregated MPI70. The operator can then see MPI congregation70as a colored spot on the surface of coupler23and note that there is a longitudinal anomaly in coupler23, as shown inFIG. 6.

In an example, where LFDA17has traversed the entire length of coupler23, power to LFDA17can be switched off, removing the circumferential magnetic field from coupler23. While coupler23continues to rotate, power to TFDA19can be switched on. Powering TFDA19passes current through the coil of electromagnetic ring59. In response, the coil of electromagnetic ring59can induce a magnetic field that will pass longitudinally through coupler23as shown inFIG. 7by flux lines71. TFDA19can be moved the length of coupler23along rails57, as shown inFIG. 4A, subjecting the entire length of coupler23to a magnetic field of the same intensity at some point during the inspection process.

Optionally, spray bar63may spray MPI fluid on the exterior surface of coupler23as shown by the arrows ofFIG. 4Awhile motorized roller49rotates coupler23and an operator monitors the surface of coupler23. At areas where coupler23is free of flaws, flux lines71pass through coupler23relatively uniformly, as shown by flux lines71passing through the lower half of coupler23inFIG. 7. At areas where coupler23has a flaw or anomaly perpendicular to the magnetic field represented by flux lines71, the permeability, the measure of how easily magnetic flux passes through a material, of coupler23will change, causing magnetic flux71to leak out of the surface of coupler23as shown at leak73. At these areas, the magnetic field will exert a magnetic force on the MPI of the MPI fluid, congregating the MPI at the anomaly and conforming it to the shape of the leak caused by the flaw. Typically, this may be the same approximate size and shape as the flaw. The ultraviolet light65shined on the exterior surface of coupler23illuminates a congregated MPI75. The operator can identify MPI congregation75as a colored spot on the surface of coupler23and note that there is a transverse anomaly in coupler23, as shown inFIG. 8.

TFDA19may make a second pass across the horizontal length of coupler23. During this pass, the operator can use the handheld fluid sprayer and handheld ultraviolet light to first spray the interior of coupler23with the MPI fluid to expose the interior surface to the ultraviolet light, thereby visually inspecting the interior surface of coupler23. As described above, at locations of anomalies, flux leakage will occur attracting MPI particles in the MPI fluid. The operator may visually see this when the MPI fluid is exposed to the handheld ultraviolet light. The operator can note any transverse anomalies on the interior surface of coupler23.

After, TFDA19has traversed the entire length of coupler23, power to TFDA19may be switched off, removing the longitudinal magnetic field from coupler23. Next, while coupler23continues to rotate, power to LFDA17may be switched on, again inducing a circumferential magnetic field in coupler23as shown inFIG. 5. Moving LFDA17the length of coupler23along rails57induces a circumferential magnetic field in coupler23along the entire length of coupler23. During this pass, the operator, instead of visually inspecting the exterior surface of coupler23, can use the handheld fluid sprayer and handheld ultraviolet light to first spray the interior of coupler23with the MPI fluid, and then expose the interior surface to the ultraviolet light, thereby visually inspecting the interior surface of coupler23. As described above, at locations of anomalies, flux leakage will occur, attracting MPI particles in the MPI fluid. The operator will visually see this when the MPI fluid is exposed to the handheld ultraviolet light. The operator will then note any longitudinal anomalies on the interior surface of coupler23.

In this manner, both the interior and exterior of coupler23may be inspected for both transverse and longitudinal flaws as well as helical flaws having both transverse and longitudinal components in one machine. This overcomes prior art problems that prevented inspection of pipe ends and couplers. For example, the disclosed embodiments provide a pipe inspection apparatus capable of inspecting couplers and pipe ends and detecting flaws in both the transverse and longitudinal directions without the necessity of electronic sensors that are dependent on the position of the coil relative to the sensor and inspected tubular member. In addition, the disclosed embodiments do not suffer from interference between the longitudinal and circumferential magnetic fields at pipe ends that prevented inspection of both transverse and longitudinal flaws in prior art devices.

Furthermore, the system and method uses active magnetic fields for inspection, rather than residual fields to enhance the detection of anomalies. The use of active fields allow the disclosed embodiments to accomplish this while preventing the longitudinal magnetic field from overcoming the circumferential magnetic field prior to inspection. Methods relying on residual magnetic fields are often unable to detect longitudinal flaws due to this problem. In the event that the coupler or pipe end becomes magnetized, TFDA17may be powered with a reverse polarity to remove the magnetization of the coupler or pipe end. Thus, the inspection station may also serve as a demagnetizer, reducing the need for manipulating the coupler or pipe into a separate demagnetization station, reducing the time and cost necessary to properly inspect the pipe ends.

An alternative example of a magnetic ends area inspection station11′ for inspecting tubular member ends and detecting anomalies is shown inFIGS. 9-13. Inspection station11′ may include all the elements of inspection station11described above with respect toFIGS. 1-8, modified as described in more detail below. Referring now toFIG. 9, the example of inspection station11′ includes a transverse flaw detection apparatus (TFDA)77and a longitudinal flaw detection apparatus (LFDA)79securely mounted to an inspection station frame assembly81. TFDA77and LFDA79may operate in a manner similar to TFDA19and LFDA17, respectively, ofFIGS. 1-4.

TFDA77ofFIG. 9includes a first electromagnetic ring83and a second electromagnetic ring85shown coaxial with first electromagnetic ring83. Both the first electromagnetic ring83and the second electromagnetic ring85are mounted to the inspection station frame assembly81so that the first and second electromagnetic rings83,85are coaxial with an axis87of a tubular member89, such as the illustrated pipe. First and second electromagnetic rings83,85include a wire coil (not shown) wound coaxial with axis87within a housing. The wire coil of each electromagnetic ring83,85couples to a DC power supply (not shown). The DC power supply, such as a Sorensen XFR Series, Xantrex Technology XFR300-9 series, or the like is configured to supply a current to the wire coil of electromagnetic rings83,85to induce a magnetic field configured to pass longitudinally through an end91of tubular member89. First and second electromagnetic rings83,85are adapted to generate a longitudinal magnetic field that passes through end91parallel to axis87. By using both first electromagnetic ring83and second electromagnetic ring85to generate the longitudinal field, the longitudinal portion of the electromagnetic field84(FIG. 9A) may be extended beyond end91of tubular member89, thus eliminating end flux leakage of issues of the prior art. This increases accuracy of the transverse flaw detection process and decreases deviations of the magnetic field caused by distance from the magnetic coils.

In the alternative embodiment, LFDA79includes a first magnetic coil93magnetically coupled to a first magnetic pole95and a second magnetic coil97(FIG. 11) magnetically coupled to a second magnetic pole99(FIG. 12). A person skilled in the art will understand that second magnetic coil97and second magnetic pole99will operate in a manner similar to that of first magnetic coil93and first magnetic pole95described in more detail below. In the illustrated embodiment ofFIGS. 9-13, second magnetic coil97and second magnetic pole99will mirror first magnetic coil93and first magnetic pole95across inspection station frame assembly81. First and second magnetic poles95,99are adapted to form a magnetic circuit across a gap101(FIG. 12) that spans between the first magnetic pole95and the second magnetic pole99. First and second magnetic poles95,99have a magnetic polarization when power is supplied to the first magnetic coil93and the second magnetic coil97. In an exemplary embodiment, the magnetic poles95,99may be oppositely polarized so that a magnetic circuit may be completed through end91of tubular member89when tubular member89is positioned within magnetic ends area inspection station11′ as illustrated above with respect to ends area inspection station11ofFIG. 5and further illustrated by flux lines90inFIG. 9B. In an example, when end91is inserted between first magnetic pole95and second magnetic pole97, and power is supplied to first magnetic coil93and second magnetic coil97, the magnetic coils93,97magnetically polarize their respective magnetic poles95,99with opposite polarization, generating a magnetic field across gap101through end91of tubular member89.

In one example embodiment, first magnetic pole93and second magnetic pole97have a length substantially equivalent to the distance between first electromagnetic ring83and second magnetic ring85, as shown inFIG. 12, permitting the circumferential magnetic field90to be passed through the entire length of end91at the same time as shown inFIG. 9B. This will increase the speed at which end91of tubular member89may be inspected. In an exemplary embodiment, this length is approximately twenty-four inches. A person skilled in the art will understand that this length may vary depending on the size of tubular member89. Each tubular member89may have an end91with a different length. End91will correspond to a portion of tubular member89that experiences undesirable flux leakage when the remainder of tubular member89is inspected.

A person skilled in the art will understand that inspection station11′ will use the MPI apparatus and generally operate as inspection station11described in more detail above with respect toFIGS. 1-8. The modifications discussed herein provide for more efficient and accurate inspection of end91. The modifications of inspection station11′ further reduce the effects of flux leakage near a terminus of end91and provide for inspection of the entirety of end91without requiring translation of LFDA77and TFDA79as with LFDA17and TFDA19described above.

Inspection station11′ includes a clamping stand103(FIG. 10) positioned closely adjacent to inspection station frame assembly81. In the illustrated embodiment, tubular member89is supported within inspection station11′ by clamping stand103. Clamping stand103includes a vertical center support beam105, a first compensating piston107, and a second compensating piston109. As illustrated, center support beam105may have two components allowing for vertical adjustment to increase a height of center support beam105. First compensating piston107has a lower end111mounted to support beam105and an upper end113mounted to an exterior end of a compensating roller bracket assembly115as shown inFIGS. 10 and 11. Compensating roller bracket assembly115includes a first roller117supported between a pair of L-shaped brackets119. First roller117is mounted on a roller axle (not shown) extending between elbows of the L-shaped brackets119. Upper end113mounts to a piston axle extending between exterior ends of the L-shaped brackets119. First roller117and upper end113may rotate on their supportive axles.

Similarly, second compensating piston109has a lower end121mounted to support beam105on an opposite side of support beam105and vertically adjacent to lower end111of first compensating piston107. Second compensating piston109has an upper end123mounted to an exterior end of compensating roller bracket assembly115opposite the first compensating piston107. Compensating roller bracket assembly115includes a second roller125supported between a pair of L-shaped brackets127. Second roller125is mounted on a roller axle (not shown) extending between elbows of the L-shaped brackets127. Upper end123mounts to a piston axle extending between exterior ends of the L-shaped brackets127. Second roller125and upper end123may rotate on their supportive roller axles.

Interior ends129,131of L-shaped brackets119,127, respectively, are supported by an axle133joining the interior ends129,131of L-shaped brackets119,127and extending through an upper end of the support beam105. L-shaped brackets119,127may pivot about axle133so that exterior ends coupled to the upper ends113,123of first compensating piston107and second compensating piston109can move in a generally vertical direction in response to actuation of first compensating piston107and second compensating piston109, as described in more detail below. Portions of interior ends129,131extend beyond axle133and contact a selectable limitation knob134that limits rotation of the L-shaped brackets119,127so that the first roller117and the second roller125may not contact one another. Limitation knob134may be any suitable size selected to maintain a preselected distance between first roller117and second roller125. For example, limitation knob134may be removed and replaced with a limitation knob134having different diameter. This will change the point of contact between interior ends129,131and limitation knob134to set a different limitation distance between first roller117and second roller125.

A pair of upwardly extending brackets135mount to support beam105below knob134and extend laterally a first distance away from the support beam105in the direction of the second compensating piston109. The upwardly extending brackets135include an upwardly extending portion137. A clamping piston139(FIG. 11) has a lower end141mounted to a lower clamping piston axle extending between the upwardly extending brackets135at the union of the upwardly extending portion137with a laterally extending portion136of each upwardly extending bracket135. A motorized roller assembly143mounts to an axle between exterior ends145of the upwardly extending portion137. Motorized roller assembly143may rotate about the axle extending between exterior ends145. Motorized roller assembly143includes a motor portion147positioned on a plate member149. Plate member149has a first end secured to the axle extending between the exterior ends145of the upwardly extending portion137, and a second end having a chain driven roller151mounted thereon. The chain driven roller151depends toward support member105and a motor portion153is positioned on the plate member149. A chain152may extend between the motor portion153and the chain driven roller151to rotate the chain driven roller151on a motorized roller axle. In the illustrated embodiment, the chain driven roller151can be rotated by the motor portion147and will in turn rotate the tubular member89as described in more detail below.

Referring now toFIG. 11, clamping piston139has an upper end155mounted to plate member149. Clamping piston139will be adapted to exert a force on plate member149that pulls plate member149toward support member105to pivot motorized roller assembly143about exterior ends145. Tubular members89can be moved into position in inspection station11′ by passing tubular member89between first roller117and second roller125and chain driven roller151. End91passes through the first and second electromagnetic rings83,85and is positioned between the first pole95and the second pole99. Compensating pistons107,109actuate to rotate the respective L-shaped brackets119,127so that the interior ends129,137contact upper portions of the limitation knob134, thereby maintaining a minimum distance between the first roller117and the second roller125. In the illustrated embodiment, the first roller117and the second roller125contact an outer surface of tubular member89so that the first roller117and the second roller125bear the weight of tubular member89. Clamping piston139will be actuated to pull the chain driven roller151into contact with the outer surface of tubular member89and exert a clamping force on tubular member89against first roller117and second roller125. Motor portion153may operate to drive chain driven roller151which will then rotate tubular member89.

As illustrated inFIGS. 14 and 15, tubular members89inspected on inspection station11′ are not perfectly cylindrical but may include a bend or bow. When supported between first pole95and second pole99, the poles95,99exert a magnetic force on end91, pulling end91of tubular member89toward first pole95or second pole99. When tubular member89is perfectly cylindrical, the magnetic forces will balance out and end91of tubular member89will maintain its position between first pole95and second pole99. When tubular member89bows or bends, end91can be closer to one of first pole95and second pole99, thus, when the magnetic fields are passed through end91while end91is rotated, end91will be pulled into contact with first pole95or second pole99. To compensate for this, first compensating piston107and second compensating piston109provide reactive forces in response to the pulling of end91toward one of first pole95or second pole99to prevent end91from contacting first pole95or second pole99, thereby maintaining end91between first and second poles95,99for inspection of end91. In an example embodiment, first and second compensating pistons107,109may be actuable pistons controlled by a programmable logic controller adapted to actuate the first and second compensating pistons107,109when an increase in force is detected at the first and second rollers117,125. In another example embodiment, First and second compensating pistons107,109, may be fluid cylinders relying on fluid friction within each cylinder to resist a compressive force exerted on first and second roller117,125by tubular member89when tubular member89subject to the magnetic forces of LFDA79. In still another example embodiment, first and second rollers117,125and first and second compensating pistons107,109include positions sensors that detect a change in physical position during the testing process. In response to a predetermined amount of physical position change, first and second compensating pistons107,109may actuate, for example, where first and second compensating pistons107,109are hydraulic or pneumatic pistons, hydraulic fluid pressure or pneumatic pressure may be applied to the first and second compensating pistons107,109to ensure that first and second roller117,125and thus, tubular member89maintain the desire position. In still another example, first and second compensating pistons107,109may be air springs having parallel plumbing controlled through a variable pressure regulator to provide resistive forces against tubular member89.

As shown inFIG. 16, inspection station11′ may be positioned adjacent two a second inspection station11′, each having a separate clamping apparatus103. When installed in this manner, two pipe ends or two pipe couplers may be inspected simultaneously, increasing the efficiency of the inspection process and reducing total costs of inspection.

The disclosed embodiments provide several advantages over the prior art. For example, the disclosed embodiments provide a magnetic inspection assembly that may inspect the ends of a tubular member or a short tubular coupler. In addition, the disclosed embodiments provide an inspection apparatus that does not leave the tubular member or coupler magnetized following the inspection process. Still further, the disclosed embodiments provide an apparatus that prevents contact between the tubular member and the inspection apparatus during the inspection process, thereby limiting damage to the ends are and the inspection apparatus.

This application claims priority to and the benefit of co-pending U.S. Provisional Application No. 61/460,785, filed on Jan. 7, 2011, entitled “Method and Apparatus for Special End Area Inspection” to Carroll Roy Thompson which application is hereby incorporated in its entirety herein by reference.