Abstract: Process for the determination of the magnetite and phosphorus contents of magnetite-containing ores. A sample of dust which has been produced artificially or obtained as byproduct is collected and placed in an electromagnetic field. The magnetite content of the dust sample is determined from changes in the magnetic flux or the relative permeability. Subsequently the phosphorus content of the total dust sample mass is determined. Also the total dust sample mass is likewise determined from changes in the magnetic flux or the relative permeability. The dust sample is preferably dried prior to measuring the change in the magnetic flux or the relative permeability. Equipment for carrying out the process includes a coil system having at least one measuring coil for determining the magnetite content. The core of the measuring coil forms a tube which has a minimum filling height that exceeds the length of the coil.

Abstract: An apparatus and process for detecting both longitudinal and circumferential defects in a test object relatively rotating and longitudinally translating with respect to a test apparatus is disclosed. Means are provided for producing a transverse magnetic field in the object. Additional means provide a longitudinal magnetic field intersecting the transverse magnetic field in the first test region of the object. Magnetic sensing means then provide output signals in response to the presence of flux leakage from the test region due to defects. Circuits responsive to the output signals are provided for indicating flaws.

Abstract: Parameters of electrically conductive material at high temperature are measured by generating, by means of a transmitter coil, an electromagnetic alternating field which induces currents in the material and by detecting, by means of a receiver coil, a specific component of the secondary electromagnetic alternating field generated by the induced currents and dependent on the measured parameter, the frequency of the generated electromagnetic alternating field being such that the penetration depth of the field into the material is of the same geometrical order of magnitude as the characteristic geometrical dimension of the system, such as the distance between the receiver coil and the material. The specific component of the secondary electromagnetic alternating field is detected by means of a synchronous detector connected to the receiver coil and controlled by a phase-shifted signal from the transmitter.

Abstract: Process and apparatus for measuring the hysteresis curves of magnetic materials when using a field coil and a potential coil of a size such that the ends of the latter coil project through the winding of the field coil. The process consists of integrating the output signal of the potential coil to obtain a first value, utilizing a voltage that is proportional to the field coil current to obtain a second value which is then added to the first value to obtain the field intensity H.In order to compensate for the presence of the legs of the potential coil, additional short windings of higher turn density are included in the field coil winding.

Abstract: A method and apparatus for monitoring the state of the surface of a moving body wherein a four-terminal eddy-current coil circuit is connected in a feedback loop of an RC resonator. The eddy-current coil circuit is placed in proximity to the monitored surface of the moving body and connected in the feedback loop of an RC resonator such that a change in the state of the surface of the moving body results in a change in the conductivity thereof, which conductivity change produces a phase displacement changing the output frequency of the RC resonator. During operation, a first data set is obtained from the coil circuit and RC resonator presenting a first runout profile of the body when the monitored state is in an initial state. The first data set is stored in a memory, and a subsequent profile is derived to obtain a second data set indicative of the operational state of the surface of the moving body.

Abstract: Nondestructive object testing is carried out in a magnetic aspect as by leakage-flux detection and in an ultrasonic aspect by electromagnetic acoustic wave generation and detection, portions of magnetic flux being derived from a common source for the respective magnetic and ultrasonic testing.

Abstract: A detection type device that includes an arrangement for detecting the energy absorbed by a resistive effect element in proximity to the inductor of a resonant circuit. The resonant circuit uses a direct current source to alternatively charge it and then let it ring through a switch connected between the direct current source and the resonant circuit. Two different parameters of the same oscillating signal generated by the resonant circuit are detected and compared. The difference is the result of a ratio of these parameters that accurately reflects the energy absorbed by the resistive effect element. This difference is used for measurement and control purposes.

Abstract: A miniaturized inspection tool, for testing and inspection of metal objects in locations with difficult accessibility, which comprises eddy current sensing equipment (12) with a probe coil (11), and associated coaxial coil cable (13), coil energizing means (21), and circuit means (21, 12) responsive to impedance changes in the coil as effected by induced eddy currents in a test object to produce a data output signal proportional to such changes. The coil and cable are slideably received in the utility channel of the flexible insertion tube 17 of fiberoptic scope 10. The scope 10 is provided with light transmitting and receiving fiberoptics for viewing through the flexible tube, and articulation means (19, 20) for articulating the distal end of the tube and permitting close control of coil placement relative to a test object. The eddy current sensing equipment includes a tone generator 30 for generating audibly signals responsive to the data output signal.

Abstract: This invention pertains to two forms of verifier of the grade of oil field tubular goods. The first form can be thought of as a sorter in that it will indicate when a particular length of tubular goods is of a different grade than its companions in a lot. The second form will identify the grade of a length. Both forms depend upon magnetizing or inducing magnetic eddy currents in the pipe which are detected and handled by the invention circuitry to sort or to identify.

Abstract: The method for detecting non-uniformities of magnetic materials resides in the use of the direct and inverse electromagnetic-acoustic conversion, effected in the zone of magnetic non-uniformities of magnetized articles. The method is characterized by effecting said conversion in an intermediate layer located in the vicinity of the material being inspected. As the intermediate layer, materials with great values of dynamic magnetostrictive constants are used. The use of the intermediate layer of a predetermined configuration enables estimation of the non-uniformity value not only singularly by the amplitude of the established elastic vibrations, but also by the number of recurrent pulses whose pulse-height distribution is conditioned by the damping factor of the intermediate layer.

Abstract: An apparatus for checking the geometrical features of mechanical pieces, including a feeler adapted to contact the macrogeometric profile of the piece to be checked, a transducer coupled to the feeler for providing a reference signal and a non-contacting sensing device including a reactive type transducer for providing a signal responsive to the microgeometry of the piece. A parameter indicative of the roughness of the piece may be obtained by processing the signals provided by the transducer coupler to the feeler and by the other transducer.

Abstract: A method and device for nondestructive testing of articles using the eddy principle current and multifrequency technique. The characteristic feature is that the measurement is generally independent of the position of the article to be tested in relation to the pickup probe. In comparison with known devices the present device is easy to handle.

Abstract: Apparatus for detecting defects such as fissures in the ferrous metal of elongated workpieces such as pipe may take the form of wall thickness and material continuity inspection apparatus that is located at an inspection site, with the inspection site being provided to receive an elongated metal workpiece such as a section of drill stem. A movable magnet support structure is located at the inspection site and carries a magnet and coil assembly in movable shoe means that is capable of engaging the outer periphery of the workpiece and establishing a predetermined spaced relationship between the workpiece, the magnet and the coil. The magnet support shoe, together with the magnet and coil, are movable in helical manner about the workpiece, causing the shoe to traverse the entire outer periphery of the workpiece during a single inspection pass.

Abstract: The proposed structural flaw detector is intended for nondestructive testing of continuously moving electrically conducting products, e.g. aluminum, copper and other rods, and comprises two eddy current transducers spaced apart along the path of movement of the products being monitored. One of these transducers is a high-frequency one and is mounted first to detect flaws on the surface, while the other transducer is a low-frequency one and is mounted downstream of the first one to detect structural flaws occurring at a depth under the surface.Arranged between the measuring channels of these transducers is a gating unit blocking the channel of the low-frequency transducer when a surface flaw is detected.

Abstract: To test a conductor with superconductive material which is in the superconducting state, the conductor is led through an external magnetic field which comprises at least two magnetic field regions spatially separated from each other and arranged one behind the other in the lengthwise direction of the conductor, the fields of which are angularly displaced from each other in the circumferential direction relative to the longitudinal axis of the conductor permitting disturbances in all superconductivity regions in superconductors of any cross section to be ascertained with certainty.

Abstract: Measuring bridge for a device for inspecting or checking by eddy currents of the type comprising a first pair of adjacent branches each constituted by a resistor and a second pair of adjacent branches in parallel with the first pair, whereof at least one of the branches is constituted by a winding which is sensitive to the faults of the part to be inspected, characterized in that it comprises a supplementary resistor connected in parallel on the said winding.

Abstract: The invention relates to a method and apparatus for the non-destructive testing of pipelines and is particularly concerned with the use of alternating eddy currents to investigate anomalies in the walls of pipelines of ferromagnetic material. A probe includes sensing coils which are connected in a bridge circuit. By employing spiral coils, placed with their axes normal to the surface of the pipeline wall, the apparatus is made less sensitive to variations in the spacing of the probe and sample. Use of biassing magnetic fields permits the detection of anomalies in pipeline walls of thickness substantially greater than the normal eddy current penetration depth.

Abstract: A device for detecting phase transformations in a magnet material is disclosed. A sample is placed in a coil coupled to a harmonic oscillator and subjected to heat radiation means for simulating predetermined heating and cooling rates which result in phase transformations within the material being tested. The phase transformations are a function of changes in magnetic permeability which vary with temperature changes.

Abstract: A flaw detection device, and method of operation thereof, for inspecting an entire workpiece, such as a tube or pipe, for the presence of defects. The detection device includes a plurality of pickup arms mounted in spaced relation with respect to each other around a work path, and a plurality of sensing coils carried by each of the pickup arms. The pickup arms are each mounted on a support member to pivot on an axis transverse to the direction of the work path so that the sensing coils may be moved into proximity and around the circumference of a workpiece as the workpiece travels along the work path.

Abstract: A magnetic testing device for detecting defects in elongated objects is disclosed. The testing device comprises a permanent magnet assembly having poles adapted to be spaced apart in the longitudinal direction of an elongated object for inducing a longitudinal magnetic flux in a section of the object between the poles of the magnet assembly which is strong enough to saturate such section of the object, a tubular pole piece substantially centered on the elongated object adjacent each pole of the permanent magnet assembly for directing the magnetic flux radially into the object at one pole and out of the object at the other pole, Hall effect devices spaced around at least one pole piece in the path of the magnetic flux for sensing the radial flux entering into the elongated object, and means for sensing the variations of such magnetic flux as an indication of loss of metallic area in the object.

Abstract: An authentication method for standardized objects, such as in particular monetary articles, in which an object to be authenticated is introduced into the field located between an emitter and a receiver delivering at least an alternative physical quantity, whose quantitative alteration produced by the presence of said object in said field is measured, the result being compared with a reference value pre-stored in a memory and distinctive of the object to authenticate, whereby, within a tolerance approximation, an authentication criterion is deducted, method characterized by the fact that said alteration is measured at different frequencies, that corresponding alterations are successively measured and then simultaneously compared with said respective reference quantities.

Abstract: A method and apparatus is disclosed whereby a solenoid coaxially surrounding an elongated electrically conducting material generates a radio frequency magnetic field of such a frequency that the material within excludes or displaces magnetic lines of force therefrom. One or more search coils are mounted coaxially within the solenoid, but outside of the material. By comparing the signal induced in the search coils when the material is present with the signal induced in the search coils when the material is absent, the outer cross sectional area of the material may be measured by measuring magnetic field exclusion or displacement, from the search coil andfrom this data, weight per unit length of solid material may be inferred. Furthermore, a pattern of deformations on the material may also be inferred, when the material is moving at known speed, from any high frequency modulation of the signal picked up by the search coil.

Abstract: A method of, and apparatus for, monitoring the alignment of a pass defined between cooperating rolls in a mill stand during rolling bar, rod or section stock. Measurement is effected through eddy current sensors which are mounted in close proximity to the ends of the rolls and provide an output indicative of the amount by which they are spaced from the roll surface. In some instances other parameters e.g. roll wear, are also measured by similar eddy current sensors appropriately located in close proximity to the roll surfaces.