Abstract: A guide device for linear guidance of elongated objects, particularly for positioning wires passing a nondestructive eddy current test device, can be the inlet nozzle or outlet nozzle, and has a brush arrangement integrated into a guide sleeve. The brush arrangement damps vibration of the wires or other elongated objects transiting the test device. A wire guided by the guide device is protected at its surface and subjected to little or no transverse vibration in the vicinity of the test probe of the test device, resulting in improved measurement accuracy.

Abstract: In a quality monitoring method it is proposed that in continuous operation a test signal be generated, digitized, logarithmized, followed by the calculation of a frequency distribution of the test signal amplitude. The frequency distribution can then be integrated in individual areas, the result for each area forming a feature of the test signal. The features of a test signal are combined into vectors, which can be used for a better evaluation of the quality of the production plant.

Abstract: A method and apparatus for testing an elongate product for faults and defects, which comprises a rotatable testing head which permits the elongate product to be passed coaxially therethrough and which mounts a pair of testing probes so as to permit adjustment of their operating diameter. In order to automatically adjust the positions of the probes to accommodate elongate products of different sizes, there is provided an external adjustment unit, which stops the testing head in a predetermined angular position. The adjustment unit contains an external adjustment drive and when the rotation of the testing head has stopped, the external adjustment drive is advanced into operative engagement with the adjustable mounting of the testing probes.

Abstract: A device for testing elongated objects, particularly wires, optionally with cross-sectional irregularities, which has a rotating test head traversed by the object and on which is provided a probe, particularly an eddy current probe, provided on rotary probe holding means and guided on circular paths about the object. For the change of the radial spacing between the object and the probe with the test head rotating, externally controllable e.g. by a sensor for irregularities, the device has a switching device with two inherently stable switching states, whereof one can correspond to a testing position near the object and another to a raised position further removed from the object and which can be rapidly set for protecting the probes.

Abstract: A search coil assembly for an inductive search device is described having a hield formed from a carrier layer and a thin metal coating applied thereupon, in which the coating is arranged into a plurality of parallel circuit tracks. The circuit tracks are electrically connected to one another by connecting tracks and to a reference potential. The described search coil assembly can be advantageously constructed by multi-layer circuit board technology.

Abstract: Detection of both surface defects of a non-ferromagnetic test body as well s the presence of ferromagnetic particles in the test body by inducing eddy currents and D.C. fields in the body. The resulting signal voltages are filtered and separately examined.

Abstract: A wire loop reference transmitter is coupled with the excitation winding and the receiver winding of metal detection apparatus and which can be alternately opened and closed through a switch. In another version the separation of the reference phase transmitter reference signal from other signals is accomplished by periodically turning the reference signal off and on at a predetermined switching frequency. According to a further version this separation is achieved by a phase control demodulator controlled by a switched-on reference signal of a first controllable phase and by a switched-off reference signal with a control signal to obtain a 180 degree second control phase. Still further, control signals of a phase controlled rectifier can be at 90 degrees to the reference signal of the reference phase transmitter.

Abstract: Method and apparatus for scanning an object with a probe in which scanning lines for the forward and backward motions run parallel to each other and their mutual spacing from each other remains constant. In one form, the object transportation speed Vt is set relative to the speed Va of the forward and backward motions in such a way that Vt/Va=tangent .alpha.=constant where .alpha. is of the angle between the line of reciprocating movement and a normal to the transportation direction. According to another feature, the angle may be controlled by Vt such that parallelism of the scanning lines is maintained.

Abstract: The devices for holding down a speciman to be tested are arranged on the e side of the tube as the transducer, without the tube movement being obstructed. The holding down devices may be arranged directly opposite to the rotation devices, or optionally in the immediate neighborhood thereof. Bending of the tube due to the holding devices does not occur even where relatively large pressing forces are used.

Abstract: Method and apparatus for magnetographic testing of magnetizable test pieces including pressing a magnetic storage tape upon the test piece, magnetizing the test piece thereof while the tape is being pressed against the test piece surface, removing the tape and scanning the tape by means of a probe which responds to magnetic forces to detect any stored defect stray fluxes.

Abstract: Voltage signals induced in a magnetic probe by stray flux at the location of a defect in a test piece are monitored determining the maximum signal magnitude and maximum signal rise. A quotient of the maximum rise and magnitude is formed and compared with a predetermined threshold value. The sample rate of rise and magnitude is functionally related to the scanning speed thereby providing accuracy independent of the scanning speed.

Abstract: A method for testing a metallic workpiece by eddy currents induced by a test coil in the workpiece, in which a measured variable that is a function of the test coil impedance serves as a measure for workpiece physical properties. The circuit includes an oscillator with an amplifier and two resonant circuits adjusted to neighboring frequencies f.sub.1, f.sub.2, the test coil impedance is at least part of the inductive component of one or both resonant circuits and a variable component influences the resonant frequency of one of the resonant circuits.

Abstract: A magneto-inductive materials tester has probes which, when brought into contact with the material, produce an electrical signal corresponding to properties of the material desired to be tested. Apparatus for evaluating this test signal has at least one device for producing a compensation voltage to eliminate residual or drift error voltages that may be superimposed on the test signal. The compensating device includes a counting pulse generator, at least one pulse counter connected to the generator at least temporarily, and a digital/analog converter connected to the pulse counter output to provide the desired compensation voltage.

Abstract: A test arrangement for non-destructive defect testing of metallic test pieces includes test probes which contactingly move across the surface of a test piece. Resilient members act on the testhead carrying the probes, one at each side of the testhead center of gravity, enabling the testhead to extend beyond the test piece edge while maintaining good contact between the probes and test piece. The testhead is adjustable with respect to the test piece surface and is maintained at a constant spacing from the test piece irrespective of test piece surface irregularities.

Abstract: The described rotating head effects A.C. field stray flux defect testing process using a rotating magnet yoke for high magnetizing field strength. The unit is compact and replaces a great number of conventional stationary devices in which the test article must be moved along a helical line past the magnet yoke. A speed of the rotating head of 900 revolutions per minute with an effective width of the probe support of 10 cm, achieves a testing speed of approximately 1.5 m/sec. This high testing speed makes the use of A.C. field stray flux testing at high magnetizing field strength possible from the economical point of view.

Abstract: The described tube testing apparatus indicates whether a defect is either external or internal, enabling a quantitative classification of defects and an analog representation on location of the defect in the tube wall. The ratio of the signal levels of a defect is taken as a threshold in two different circuit channels. For tubes of a given wall thickness, the ratio of the defect signal levels resulting in the two channels is a fixed number which is a function of the location of a defect in the tube wall causing a defect signal. Uninfluenced test signal voltages from the first channel are available for further evaluation and are applied to voltage discriminators having various threshold voltages.

Abstract: A magnetic field probe is supported within a hollow base at one end by a resilient spring element and at its other end by a member adjustable to move the probe transversely of the axis defined by the probe ends. The spring element biases the probe in a direction transversely of the probe axis.

Abstract: At least two groups of scanning coils are arranged with respect to the surface of metal parts to be tested at different angles. Means are further provided for oscillating at least one group of scanning coils in a direction generally perpendicular to the normal direction of travel of the scanning coil. Optionally, the exciter windings are rectangular, circular or oval.

Abstract: An eddy current coil test assembly comprises a printed circuit board having respective conductors which form the excitation coil winding, the sensing coil winding, the input transformer winding, the output transformer winding and the connections between these respective elements. Pot core type transformers are mounted in close proximity to said windings. The printed transformer windings constitute respectively the secondary winding of the input transformer and the primary winding of the output transformer.

Abstract: A representative reading for the concentration of a suspension of luminous and magnetizable particles is provided in every case, even when luminous but non-magnetizable particles are also present. That is, the presence of non-magnetizable luminous particles in the suspension have no effect on the determination. A rotating wheel-like member has its lowermost portions immersed in a supply of the magnetic particle suspension in a fluid carrier. The circumferential periphery includes a permanent magnet having a gap extending continuously around the periphery and covered over by a plastic rim. As the wheel-like member rotates, the magnetic particle suspension forms a bead along the magnet gap. Ultra violet radiation directed onto the bead causes the magnetic particles to fluoresce and the degree of fluorescence is measured by photosensitive means.