摘要:
The system and method provides a means for inspecting pipelines that have obstructions which prevent conventional inspection pigs from passing the obstructions. The invention is a system and method that uses remote-field eddy current inspection techniques and a uniquely configured excitation coil for inline inspection of pipelines having valves and other fittings that severely restrict or prevent the use of conventional inspection pigs. The invention relies on a unique collapsible excitation coil and a collapsible sensor array that enables an inspection pig incorporating the invention to pass pipeline obstructions that prevent passage by conventional inspection pigs. The invention provides a means for reducing the diameter of the inspection pig to enable it to pass obstructions in the pipeline.
摘要:
A method for measuring conductance of a sample using an eddy current probe with a sensing coil. The method includes N repetitions of measuring first and second voltage pairs including in-phase and quadrature components of an induced AC voltage in the sensing coil, calibrating the first signal based on the measured second signal at a different separation from the sample and reference material, determining a conductance function relating conductance with location along the selected curve, processing the calibrated first voltage pairs to generate a lift-off curve, determining an intersection voltage pair representing intersection of the lift-off curve with a selected curve, and determining the conductance of the sample from the intersection voltage pair and the conductance function.
摘要:
A method and apparatus are provided for measuring the thickness of a test object. The apparatus includes an eddy current sensor having first and second sensor heads. The sensor heads are positioned to have a predetermined gap therebetween for passage by at least a portion of the test object through the gap. The sensor heads make measurements at given sampling locations on the test object as the test object is moved through the gap. The apparatus also includes a position sensing mechanism to determine positions of the sampling locations on the test object. The apparatus also includes an evaluation circuit in communication with the eddy current sensor and to the position sensing mechanism for determining the thickness of the test object at the sampling locations.
摘要:
A winding type magnetic sensor device includes a sensor core facing an object to be detected, an excitation coil wound around the sensor core, and a detection coil wound around the sensor core that defects a variation of magnetic flux corresponding to the object to obtain a detection signal for the object. A constant current drive circuit is provided that supplies a constant current to the excitation coil.
摘要:
A device and method is taught for detection of flaws and localized wall loss in pipes made of ferromagnetic-based material. The device utilizes a magnetic field generator to create a horizontal magnetic field of flux. A pipe is passed through the magnetic field where a magnetic fluctuation detector, for example multiple groups of hall units, identifies fluctuations in the magnetic field.
摘要:
A sensor for monitoring a conductive film in a substrate during chemical mechanical polishing generates an alternating magnetic field that impinges a substrate and induces eddy currents. The sensor can have a core, a first coil wound around a first portion of the core and a second coil wound around a second portion of the core. The sensor can be positioned on a side of the polishing surface opposite the substrate. The sensor can detect a phase difference between a drive signal and a measured signal.
摘要:
Disclosed are apparatus and method for measuring Hall effect related-values in a semiconductor, such as a mobility, a carrier concentration and a resistivity using a Hall effect. A sample is loaded into an IC socket or a similar target, which is fixed on the inside of a heat insulating material container capable of containing injected liquid nitrogen. The Hall effect related-values are measured using a moving member for moving a pair of permanent magnets to an outside of the heat insulating material container. The measuring equipment has a simple structure, and a measuring operation is simple. A level of an input voltage of a sample is measured depending on a constant current that is supplied by a constant current supplying unit contained in a Hall voltage measurement unit. A measurement error detection unit detects and displays a measurement error of the sample using the level of the measured input voltage. Since the measurement error is detected before measuring the Hall effect, the measurement error can be excluded.
摘要:
A magnetic flux detector comprises a core member 12 and an armature member 11, and the core member 12 generates a magnetic flux by an exciting coil 13 when the exciting coil receives an excitation current controlled by an excitation current controller 30. The magnetic flux detector further comprises a search coil 14, which is provided in a magnetic path for the magnetic flux, and a magnetic flux calculator 40, which determines the magnitude of the magnetic flux by measuring an electromotive force induced in the search coil 14 by a change in the magnetic flux. The excitation current controller 30 controls the excitation current to increase from zero to a predetermined current value during a first predetermined time period T1 and then to decrease from the predetermined current value to zero during a second predetermined time period T2, and the magnetic flux calculator 40 determines the magnitude of the magnetic flux based on the difference between the increasing electromotive force integral value which is calculated by integrating the electromotive force induced in said search coil 14 during the first predetermined time period T1 and the decreasing electromotive force integral value which is calculated by integrating the electromotive force induced in the search coil 14 during the second predetermined time period T2.
摘要:
The invention relates to measurement technology and can find application for nondestructive testing electrically conducting and/or ferromagnetic materials and products. The differential eddy-current transducer comprises a primary detector (1) which incorporates two similar search coils (2, 3) and an additional coil (4) having its leads connected in series aiding to respective first leads of the search coils (2, 3) to second leads of which voltage is applied in antiphase. The transducer further comprises an electronic unit (5) which is electrically connected to the primary detector (1) and incorporates a potentiometer (6), a capacitive element (7), and an operational amplifier (8). Two leads of the potentiometer (6) are connected to common connection points of the leads of the search coils (2, 3), and its midpoint lead is connected to the capacitive element (7) which in turn is connected to the inverting input of the operational amplifier (8) whose noninverting input is grounded. The output of the operational amplifier (8) serves as the output of the electronic unit (5). The eddy-current transducer is capable of enhancing the measurement accuracy due to compensating for temperature errors, increasing the resolution and noise immunity thereof.
摘要:
A Barkhausen probe comprising a magnetizing field generator, a magnetoresistive magnetic field sensor, a direct current power supply for biasing the magnetoresistive magnetic field sensor and signal conditioning electronics is described. The Barkhausen probe being capable of generating and sensing the Barkhausen noise emanating from the surface of a cyclic magnetized specimen. The conditioned Barkhausen noise output of the signal conditioning electronics being usable as input to various analysis systems where textural analysis of the material can be performed.