Abstract: An eddy current instrument for non-destructive testing of a tubular metallic object, the instrument comprising a probe head with probe coils and probe coil signal conditioning and analog to digital conversion electronics and a probe connector module with a processor and probe coil excitation signal generation electronics. The probe connector processor is configured to interface to an external computing device, which may be a personal computer. The probe head and probe connector module may be connected by a rigid shaft or by a flexible coupling.

Abstract: A flexible eddy current probe for non-destructive testing of a metallic object may include one or more plus-point coils and a flexible printed circuit having first and second parallel sides, third and fourth parallel sides, and a number of adjacent strips. The strips have first and second ends that are contiguous with the first and second parallel sides, respectively. Each of the strips may contain a pair of coils oriented along the length of the strip, a first coil being proximate to the first end and a second coil being proximate to the second end, and each of the coils is configured to excite an eddy current in the metal object or to sense an eddy current. Each of the strips may also be independently flexible from one another. The eddy current sensor array is configured to be scanned over the metal object.

Abstract: A drive coil assembly to generate a specific spatial distribution of eddy currents within the walls of a conductive tube or pipe, which may be used in conjunction with a separate array of magnetic sensors to detect defects in the tubing wall. The drive coil assembly comprises a plurality of coils which are generally wrapped around the circumference of a cylindrical probe body, but which are further shaped with serpentine undulation in the axial direction. The undulation is characterized by a spatial amplitude, a spatial phase and a spatial frequency; typically, the spatial frequency results in an integer number of undulations around the circumference of the drive coil and the phase is chosen to uniformly distribute the lobes about the circumference. The temporal phase of the electrical current in each coil is chosen to null out net current of the assembly around the circumference.

Abstract: A flexible eddy current probe for non-destructive testing of a metallic object, the probe having a flexible printed circuit containing eddy current drive and sense coils and a rotary encoder configured to measure liner distance as the eddy current probe is scanned over the object. The probe features an encoder arm that adjustably connects a flexible eddy current sensor array to the rotary encoder.

Abstract: A system for displaying an area covered in a non-destructive scan of an area larger than the test probe is disclosed. Position encoders are included on the test probe to track the motion of the probe and to provide a record of the portion of the area under test that has been covered by the probe.

Abstract: A device and method of eddy current based nondestructive testing of tubular structures made of electrically conductive materials is disclosed. The device includes a plurality of excitation electromagnets having an axis of symmetry and magnetoresistive sensors having an easy axis for magnetic field sensing; wherein the magnetoresistive sensors are arranged in a circular array on a single plane with the easy axis aligned radially with respect to the circular pattern and wherein the electromagnets are arranged in a circular pattern on both sides of the plane with their axes of symmetry being arranged parallel to the plane and orthogonal to radii of the circular pattern on which the electromagnets are placed.

Abstract: A rotating field eddy current probe for sensing flaws in electrically conductive tubing is disclosed. The probe includes two stimulation coils physically arranged at 90 degrees to each other about an axis a current sensing portion. The a first alternating current is applied to one of the stimulation coils at a first phase and a second alternating current is applied to the second of the stimulation coils at a second phase, said second phase being electrically 90 degrees apart from said first phase and creating a rotating oscillating magnetic field.

Abstract: A device and method of eddy current based nondestructive testing of tubular structures made of electrically conductive materials is disclosed. The device includes a plurality of excitation electromagnets having an axis of symmetry and magnetoresistive sensors having an easy axis for magnetic field sensing; wherein the magnetoresistive sensors are arranged in a circular array on a single plane with the easy axis aligned radially with respect to the circular pattern and wherein the electromagnets are arranged in a circular pattern on both sides of the plane with their axes of symmetry being arranged parallel to the plane and orthogonal to radii of the circular pattern on which the electromagnets are placed.

Abstract: A method of establishing position dependent focal laws and dynamically accessing these focal laws during inspection is disclosed comprising the steps of partitioning a CAD model into distinct geometric regions prior to inspection, generating a dedicated set of focal laws for each of the geometric regions, and associating each position of the scanner with one of the geometric regions. A method of compressing an A-Scan using a windowing technique is also disclosed. Additionally, methods for computing and displaying volumetric slices in real-time are disclosed. Finally, a method of firing multiple probes at different firing frequencies is disclosed, as well as a multi-probe inspection system that enables parallel firing.

Abstract: A method of analyzing historic and current eddy current test probe data is disclosed. The method takes into account that the two data sets of data may not be an exact match in acquisition technique based on factors such as probe pull speed, direction, record leg or instrument configuration. The method includes the steps of aligning a first set of eddy current data to a second set of eddy current data based on prominent features found in both data sets; converting the first set of eddy current data to a modified first set of eddy current data to match the second set of operating conditions and; comparing the modified first set and the second set to find change over time.

Abstract: A rotating field eddy current probe for sensing flaws in electrically conductive tubing is disclosed. The probe includes two stimulation coils physically arranged at 90 degrees to each other about an axis a current sensing portion. The a first alternating current is applied to one of the stimulation coils at a first phase and a second alternating current is applied to the second of the stimulation coils at a second phase, said second phase being electrically 90 degrees apart from said first phase and creating a rotating oscillating magnetic field.

Abstract: A system and method for precisely detecting tubing flaws using a computer architecture that combines scalable processing power with an extensible array of detection and classification possibilities involving eddy current data analysis, as well as detection algorithms for pinpointing exact tubing regions and wherein these regions can be further divided into manageable segments for flaw analysis. Multiple classification tools utilized to discriminate detection and to precisely assign proper report codes to detect flaws repeatedly and accurately.

Abstract: A system and method for precisely detecting tubing flaws using a computer architecture that combines scalable processing power with an extensible array of detection and classification possibilities involving eddy current data analysis, as well as detection algorithms for pinpointing exact tubing regions and wherein these regions can be further divided into manageable segments for flaw analysis. Multiple classification tools utilized to discriminate detection and to precisely assign proper report codes to detect flaws repeatedly and accurately.

Abstract: An apparatus for automated inspection and repair of a tube sheet. The apparatus has a rotating gripper pod, comprising at least one tube gripper, a sliding body portion containing the gripper pod; a housing portion comprising at least one tube gripper and a tool head coupling. The tool head coupling swapably attaches to a eddy current test probe and at least one kind of tube repair tool. Novel, auto-locking tube grippers are also disclosed. A serial bus connects electronic modules within the apparatus and also connects the apparatus to an external controller.

Abstract: A flexible shaft of nonrigid components for use in pushing an eddy current probe through small diameter pipe bends includes a thin-walled flexible outer sleeve enclosing a data cable helically coiled around a central inner core, typically of braided wire. The inner core is functionally incompressible and inextensible to sustain compressive forces derived from pushing the shaft through a pipe. The outer sleeve supported from within by the data cable and the inner core for sustaining lateral forces of pusher rollers is longitudinally even and smooth to advance the shaft without damage to it.

Abstract: In an eddy current probe shaft, a sleeve encloses an inner core of length shorter than the sleeve causing the inner core to curl within sleeve. The inner core includes data cables that typically comprise coaxial cables to which the sleeve is attached at shaft lead and trail ends. The shaft is assembled by stretching the sleeve over the inner core and securing the stretched sleeve to the inner core, the sleeve causing the inner core to curl as the sleeve returns to its unstretched length. Slack thus produced in the inner core, and particularly in the coaxial cables, allows the probe to bend without stressing the coaxial cables and without two coaxial cables within the sleeve moving relative to each other therein eliminating signal drift phenomenon caused by a change in capacitance characteristics of the coaxial cables when insulation of the coaxial cables stretch upon bending.

Abstract: A digital synthesizer generates an electrical digital carrier that is converted to analog and driven a probe coil to generate an electromagnetic wave propagated into a test material proximate the probe coil. A return electromagnetic wave generated by eddy currents in the material includes signatures of material defects modulated on the return carrier electromagnetic wave. The return wave is detected by one or more probe coils and amplified. A second amplifier is applied selectively amplifying the signal in segments such that each segment exploits the input range of the analog to digital converter. The signal is then converted from an analog signal to a digital signal and then digitally mixed with digital sine and cosine functions also generated by the digital synthesizer to yield sum and difference values. A gain scaling stage then trims the signal to overcome circuit imprecision such that the amplification in each respective segment is a power of two.

Abstract: A method and apparatus of a digital synthesizer generating an electrical digital carrier that is converted to analog and driven a probe coil to generate an electromagnetic wave propagated into a test material proximate the probe coil. A return electromagnetic wave generated by eddy currents in the material includes signatures of material defects modulated on the return carrier electromagnetic wave. The return wave is detected by one or more probe coils and amplified. A second amplifier is applied selectively amplifying the signal in segments such that each segment exploits the input range of the analog to digital converter. The signal is then converted from an analog signal to a digital signal and then digitally mixed with digital sine and cosine functions also generated by the digital synthesizer to yield sum and difference values. A gain scaling stage then trims the signal to overcome circuit imprecision such that the amplification in each respective segment is a power of two.

Abstract: A digital synthesizer generates an electrical digital carrier that drives probe coil to generate an electromagnetic wave propagated into a test material proximate the probe coil. A return electromagnetic wave generated by eddy currents in the material includes signatures of material defects modulated on the return carrier electromagnetic wave. The return wave is detected by one or more probe coils, amplified, converted from an analog signal to a digital signal and then digitally mixed with digital sine and cosine functions also generated by the digital synthesizer to yield sum and difference values, mathematically expressing various eddy current signals received by the probe in a complete set of orthogonal functions. A low pass filter then removes all but the difference values. A direct current reference component is subtracted from the mixed digital signal, which translates the signal to center about a zero axis for ease of display and analysis.

Abstract: An eddy current probe comprising two solenoid coils wound around a common rectangular wafer base of high permeability material extending beyond the coils at wafer corners with the wafer becoming the solenoid core. Posts also of high permeability material depend from a wafer front at its corners with coils crossing orthogonally on the wafer. The coils are connected to alternating current to produce magnetic fields that have like magnetic poles at wafer corners diagonally opposed across the wafer, the coils switching in phase to alternate the magnetic field between posts at base diagonal corners. With the posts at the wafer base corners, the combined magnetic fields generated from the orthogonal coils conduct through the posts and emanate from post ends. The post ends have a curvature matching that of a material to be tested for better coupling the magnetic field into the material.