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4742298 |
Apparatus for detecting surface flaw of pipeline by electromagnetic induction
An apparatus for detecting a surface flaw of each pipe constituting a pipeline, including a pig capable of travelling along pipeline and being provided with the following elements: a cylindrical...
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4727322 |
Method and apparatus for measuring thickness of a test part by an eddy current sensor, without contact and with lift-off compensation
A method of measuring a characteristic, such as thickness, of a test part makes use of the variation in impedance of a coil in a senor caused by eddy currents generated as a result of the proximity...
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4716366 |
Eddy current distance signal apparatus with temperature change compensation means
Eddy current distance measuring apparatus includes a multiplier connected to one secondary coil of a pair of secondary coils in an eddy current sensor. The secondary coil outputs are inputted to a...
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4704578 |
Thermal compensation method for a magnetic circuit having an oscillating circuit with an inductance coil
The present invention involves a thermal compensation procedure for magnetic circuits, such as those used in security devices detecting metallic masses, whose losses increase as a function of...
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4703265 |
Method and apparatus for compensating for different depths of sun currents induced in the object tested for imperfections
A method for testing an electrically conductive test object with regard to an imperfection therein uses a transducer supplied with drive signals of two different frequencies so that via inductive...
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4698590 |
Method and apparatus for measuring velocity of ferromagnetic tubing
A tubing trip tool for use in determining the extent of defects in tubular elements comprising a continuous string used in a subterranean oil or gas well during removal of the string from the well...
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4695797 |
Method of and apparatus for layer thickness measurement
A method of and apparatus for measuring the layer of coating thickness of non-magnetic substances on a ferromagnetic parent material by the magneto-inductive method or of non-metallic substances on...
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4686471 |
System for online-detection of the transformation value and/or flatness of steel or a magnetic material by detecting changes in induced voltages due to interlinked magnetic fluxes in detecting coils
A system for online-detection of a transformation value and/or a flatness of a steel or a magnetic material includes: an exciting coil disposed at either side of the plate-shaped steel or magnetic...
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4684888 |
Apparatus subject to random accelerative motion for sensing motion of a magnetically susceptible part
A magnetically susceptible part motion sensor where the sensor is subject to random accelerative conditions. The sensor comprises a first accelerometer and magnet combination and a second...
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4683429 |
Electrical circuit which is linearly responsive to changes in magnetic field intensity
A circuit including a magnetic sensing device for measuring magnetic fields is disclosed. The output of the magnetic sensing device is amplified by an amplifier and feedback to the magnetic sensing...
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4677377 |
Position-detecting sensor for detecting position of a moving object utilizing magnetism
A position-detecting sensor comprises a magnetic recording medium carried on a moving object and having a signal track recording a magnetic signal, a first MR element disposed nearby the magnetic...
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4673877 |
Zirconium liner thickness measuring method and an apparatus therefor for a zirconium alloy tube
A method and apparatus for measuring a liner thickness of a zirconium liner provided at the inner surface of a zirconium alloy tube, the principle of measurement of which is to insert coils into...
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4672317 |
Multi-gap head apparatus for use with a magnetic scale
A multi-gap head apparatus employed in a measuring system using a magnetic scale. First and second thin plates, making up core members, are stamped out with a selected width near the center portion...
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4667157 |
Linear Hall effect oxygen sensor with auxiliary coil magnetic field balancing
An oxygen sensor utilizes the paramagnetic property of oxygen to determing the relative concentration of oxygen in a test gas. The test gas is supplied to the core of an electromagnet or the gap of...
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4661777 |
Plural frequency eddy current method and apparatus with lift-off compensation for detecting faults in electrically conductive objects
In the testing of electrically conductive test objects for the presence of flaws and the like using a transducer to generate electrical currents in the test object and to inductively sense such...
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4659989 |
Inductively balanced metal detector circuit with orthogonal balancing signals and including phase and polarity detection
Metal detection apparatus includes an oscillator coil 101 driven by an oscillator 101, which induces in detector coils 103,104 equal and opposite E.M.F.s such that a nominally zero output is...
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4647854 |
Apparatus for measuring the level of the molten metal in the mold of a continuous casting machine
An apparatus for measuring the level of molten metal in the oscillating mold of a continuous casting machine in operation by an eddy-current type distance measuring device. The oscillation signal...
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4646012 |
Digital, electromagnetic rod position indicator with precisely controlled transitions between digital states
A digital rod position indicator having discrete coils spaced along the travel path of an elongated magnetically permeable member stores in digital form compensation signals for automatically...
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4646013 |
Method and apparatus for eddy current testing by at least two different frequency signals
During so-called eddy current testing by way of several frequencies, it is often difficult efficiently to separate and detect superficially located defects from the disturbances caused by a varying...
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4646014 |
Hall effect field sensor circuit with temperature compensation using OP amplifier
A Hall effect magnetic field sensing circuit provides an operation amplif which is connected to a signal voltage terminal of the Hall effect sensor with a negative temperature coefficient (TK) of...
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4644274 |
Apparatus for supporting an eddy current probe used to scan an irregular surface
An invention is disclosed which supports an eddy curent probe at a predetermined distance from a surface to be scanned. In another embodiment, the probe is scanned by rotation about an axis and...
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4641092 |
Rotary probe apparatus for detecting flaws in a test object
A flaw detection apparatus for detecting flaws at the outer surface of a product, such as a steel bar, wire or steel pipe, which is round in section and produced by the hot rolling, by use of a...
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4631477 |
Method for eliminating spurious signals in a measuring installation for identifying the position of a rigid body in space
A method for measuring the position, attitude and/or positional or attitudinal change of a fixed body in space, such as the lower jaw of a patient in a dental examination, utilizes signals obtained...
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4628265 |
Metal detector and classifier with automatic compensation for soil magnetic minerals and sensor misalignment
Metal detector for locating and classifying metal objects of different types in the ground or other surroundings. Automatic compensation is provided for signals produced by magnetic materials in...
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4620152 |
Lift-off compensation of eddy current probes by translating without rotation the X-Y coordinate plot of the complex locus of the probe output
This invention relates to a method and apparatus for compensating the output signal of a reflection type eddy current probe so as to minimize the change in the phase shift of the probe output...
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4609871 |
Temperature compensated optical fiber interferometric magnetometer
Temperature compensation of an optical fiber interferometer is achieved by wrapping and bonding one fiber arm transversely about the length of a magnetostrictive rod which is sensitive only to the...
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4609870 |
Lift off compensation of eddy current crack detection system by controlling damping resistance of oscillator
An eddy current crack detection system has an inductive probe coil forming part of an oscillatory circuit. The coil voltage is fed to a measuring device a change in amplitude of the coil voltage...
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4608534 |
Eddy current probe for detecting localized defects in cylindrical components
Eddy current probes which are used to internally or externally inspect cylindrical components for localized defects have a main coil arrangement that induces and senses eddy current in the...
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4604574 |
Rotating probe indicating the angle of intersection with a surface
The relative orientation of a probe and a surface is maintained by positioning a proximity sensor off-axis on the probe, rotating the probe, and using the signal from the probe to adjust the...
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4603365 |
Magnetic detection apparatus
A magnetic detection apparatus for use in an encoder includes a first magnetic sensor for detecting an external magnetic field and a second magnetic sensor for detecting a signal magnetic field....
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4573012 |
Method and apparatus for measuring core loss of a laminated ferromagnetic structure
A core loss tester employs separate cables for excitation and pickup. Testing is performed at a fixed flux density in the ferromagnetic core. A processing circuit on the output of the pickup coil...
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4567435 |
Method and apparatus for continuously measuring distance utilizing eddy current and having temperature difference influence elimination
The distance between the tip of a probe and a high-temperature object of measurement is continuously and accurately measured by arranging the probe comprising a primary coil and a pair of secondary...
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4564809 |
Eddy current test method with degree of amplification selected in accordance with a compensation signal
A method and an instrument for testing materials using the eddy current principle, at different frequencies depending on the output quantity of a coil system, compensation values are generated...
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4556846 |
Eddy current testing device with a balancing digital memory
Eddy current non-destructive testing device comprising in per se known manner an exciting generator, a probe connected to the latter, means for sampling in the probe a measuring voltage, means for...
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4555664 |
Process and device for inspecting a surface in simulated manner which differs from the real surface scanning by an eddy current transducer
The invention relates to a process and to devices for the inspection of the surface of a member by means of an eddy current probe. By scanning the member means of the transducer following a given...
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4553094 |
Method and apparatus for measuring conductivity using eddy currents with temperature compensation feature
Method and apparatus for measuring conductivity of test materials at a measurement temperature and displaying material conductivity at standard temperature by compensating the measured conductivity...
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4543527 |
Proximity switch exhibiting improved start-up characteristics
A new and improved method and apparatus is disclosed for detecting a target location with respect to an inductive tank circuit. A sensing field such as an electromagnetic field is established...
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4529936 |
Supply circuit including a pair of amplifying channels for an eddy current probe with two windings
Supply circuit for an eddy current probe with two windings, comprising two parallel supply channels connected to the probe by a cable, each channel incorporating a reference winding and an...
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4528506 |
Ferromagnetic resonance probe liftoff suppression apparatus
A liftoff suppression apparatus utilizing a liftoff sensing coil to sense the amount a ferromagnetic resonance probe lifts off the test surface during flaw detection and utilizing the liftoff...
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4527121 |
Short-circuit-protected evaluation circuit of high stability for variable inductance transducers
The inductance of a variable inductor is put in series with a resistor to provide a delay circuit at the output of an amplifying path and the delayed voltage is fed-back to produce square waves...
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4524932 |
Railroad car wheel detector using hall effect element
A Hall effect element, incorporated into an integrated circuit unit with temperature compensation, voltage regulation, and amplification, is mounted on top of a permanent magnet made of ceramic...
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4518917 |
Plural sensor apparatus for monitoring turbine blading with undesired component elimination
A plurality of proximity sensors are disposed in a turbine flow guide to measure flow guide-to-turbine blade tip distance at various points around the flow guide. The sensor signals are detected...
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4514690 |
Power line field interference rejection for magnetic sensors
The discriminator consists of two major parts; a nonlinear filter for low vel rejection, and inhibiting logic for high level rejection, of ac magnetic fields. The nonlinear filter approximately...
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4510447 |
Inspection apparatus for electromagnetically detecting flaws in the wall of a pipe
Apparatus for detecting flaws in the wall of a ferromagnetic pipe is disclosed. The apparatus comprises an electromagnetic having poles in slideable contact with the surface of the wall of the...
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4509023 |
Oscillator with a temperature compensated oscillating coil
A method of using the temperature coefficient of the copper resistance of an oscillating coil to compensate for the temperature coefficient of the quality factor of the same oscillating coil. To...
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4506220 |
Temperature compensated magnetoresistive effect thin film magnetic sensor
A magnetoresistive effect thin film magnetic sensor has a temperature compensating magnetoresistive effect (MR) element arranged non-parallel to a signal detecting MR element to prevent the...
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4503922 |
Electronic bathroom scale apparatus using planar coil sensors
An electronic bathroom scale employs a low profile planar coil position sensor which responds to the positioning of a pivotable lever system. The levers are coupled to a platform which moves in the...
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4488114 |
Device for non-destructive testing by eddy currents comprising air-gap correction means
Process and device for non-destructive testing or inspection by eddy currents with correction of the air gap effects. A differential measurement and an absolute measurement are performed and the...
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4447517 |
Method of developing electrostatic latent images
The disclosure is directed to an improved electrostatic latent image developing method in which uneven development arising from simultaneous employment of a magnetic roller rotational driving...
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4424486 |
Phase rotation circuit for an eddy current tester
An Eddy Currest Tester for detecting defects in conductive materials employs phase rotation circuitry for eliminating the effects of lift-off signals from the reactive component of the output of an...
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