Abstract: An electromagnetic tagging system is provided for remotely detecting and locating polymeric and other non-conductive structures situated behind barriers, such as underground plastic pipes or containers. The system comprises a fluctuating magnetic field source, a pattern of tags embedded in discrete regions of the wall of the polymeric structure, each tag including an amorphous magnetic metal target for generating a Barkhausen response when exposed to the fluctuating magnetic field source, and a portable detection circuit movable along the ground or other control surface for remotely detecting the Barkhausen response. The amorphous magnetic material in each tag is preferably in the form of a plurality of elongated particles having aspect ratios of at least 3 to 1 and arranged end-to-end.

Abstract: The invention relates to method and apparatus for measuring and displaying the eccentricity or off-set position with respect to coaxiality of a metallic conductor within an insulating coating during an extrusion process. The measuring apparatus employs a combination of optical and electrically inductive techniques to determine respectively the position of the outer coating of the cable and that of the core within the cable. By relating these positional measurements it is possible to determine the position of the core relative to a desired location namely the coaxial position so that appropriate corrections can be made to the extrusion process to keep the core in that coaxial position.

Abstract: A sonde for tracing an underground conduit has a separable casing which receives a removable inner shell, the transmitter electronics being located in the shell. The electronics may be permanently potted in the inner shell or removable therefrom. The interchangeability of the transmitter facilitates the use of different types of transmission signals without requiring the more expensive casing for each such transmitter. The shell also advantageously supports the battery, and further is free to rotate within the housing such that, as the cap is screwed onto the housing, the shell and battery are free to rotate, precluding damage to the battery leads which may be caused by twisting of the leads.

Abstract: The encoder element (8) for a rolling-contact bearing equipped with an information sensor assembly is rendered integral with a rotating race of the bearing and interacts with a sensor of the said information sensor assembly in order to detect the speed of rotation of the bearing. It comprises an annular target (13) made of ferromagnetic material provided with a cylindrical bearing surface (13a) for mounting on the rotating race of the bearing and with a flat disc-shaped radial part (13b) with windows (13c) or slots of identical size and uniformly distributed along the circular path, and an axially magnetized bipolar ring (14) provided with axial crenellations (14b) which are uniformly and circumferentially distributed and which penetrate axially into the said windows or slots in the target.

Abstract: A structure provides a gradient field useful in magnetic resonance imaging. Axially aligned, solenoidal-like coils are symmetrically distributed around the perimeter of the bore of a superconducting magnet in an MRI system so as to produce transverse gradients in the X and Y directions with exceptionally high efficiency and exceptionally low acoustic noise. Opposed solenoidal endcoils may be added to reduce axial flux leakage by generating an axial quadrupolar field. Radially aligned coils may be positioned near each end of the axial coils to reduce leakage flux by adding a transverse quadrupolar field to form a resulting octopolar field. Typically, the solenoid-like coils have a mean radius of about 15% of the radius of that of the imaging ellipsoidal region. A thick-walled stainless steel, copper and resin cylinder may be used to simplify gradient shielding problems. Silver plated bronze or stainless steel sheet is used as an rf shield.

Abstract: A method and apparatus is provided for measurement-while-drilling utilizing improved antennas. An elongated tubular member is provided with an outer peripheral surface having a contoured portion defining a plurality of discrete communication regions of reduced radial dimension. An antenna pathway is defined in the elongated member substantially transverse to the plurality of discrete communication regions. An antenna member is partially disposed in the antenna pathway with portions of the antenna member extending out of the elongated member at the plurality of discrete communication regions to facilitate communication of electromagnetic energy. In a reception mode of operation, the antenna member detects electromagnetic energy in the wellbore and generates a current corresponding thereto. If operated in a transmission mode of operation, the antenna member emits electromagnetic energy in the wellbore in response to an energizing current.

Abstract: The invention relates to method and apparatus for measuring and displaying the eccentricity or off-set position with respect to coaxiality of a metallic conductor within an insulating coating during an extrusion process. The measuring apparatus employs a combination of optical and electrically inductive techniques to determine respectively the position of the outer coating of the cable and that of the core within the cable. By relating these positional measurements it is possible to determine the position of the core relative to a desired location namely the coaxial position so that appropriate corrections can be made to the extrusion process to keep the core in that coaxial position.

Abstract: A seal with internal reinforcement is mountable on a stationary ring of a bearing, an insulating film with conductive tracks being fixed to the reinforcement. A sensor element, for sensing an encoder element carried by a rotating ring of the bearing, contacts the insulating film and the conductive tracks. Constitutive material of the seal covers at least a portion of the reinforcement and the insulating film and provides protection for the conductive tracks and sensor element. Connecting devices for passing wiring through the reinforcement are also described.

Abstract: Described is a sensor based on the magnetoresistive effect and integrated into the thin-film arrangement of a remagnetization line in the form of a meander. In an adaptation to this meandering structure, the magnetoresistive film strips are provided in regions with alternating positive- and negative-inclined Barber pole structures. When periodic remagnetization of the regions takes place, a drift-free AC voltage is obtained as a sensor output signal. This lack of drift is the presupposition for the use of the magnetic field sensor for precise measurement of weak magnetic fields.

Abstract: Rolls of metallized strip material are changed automatically at a station incorporating a device by which the thickness of the strip material is sensed utilizing a resonant circuit driven at a frequency other than its own resonant frequency and consisting in a coil with a toroidal core affording an opening or gap through which the running strip material is directed; a voltage sensor connected to the terminals of the coil pilots the operation of two switched outputs by way of respective comparators such as can be preset and activated parametrically in response to selected voltage values registering at the terminals of the coil with variations in inductive reactance determined by and indicating the thickness and the electrical and physical properties of the passing strip.

Abstract: An inductive displacement sensor has first and second elements which define a path for movement. The first element has coil portions which interact with an inductance affecting part of the second element so that the inductances of the coil portions vary with movement of the inductance affecting part, only some of the coil portions being affected by the inductance affecting part at any time. The coil portions are arranged in two series connections, each series connection being at least two coil portions electrically connected in series. Coil portions of the two series connections are then arranged alternately. In this way, substantially sinusoidal output signals may be obtained.

Abstract: A multi-coil measuring system for electronic apparatus having five pick up coils, for picking up the magnetic field intensity of the electronic apparatus, mounted in a plexiglass block which has a Velcro strap to secure the electronic apparatus to the block. The coils are electrically connected to a connector that leads to a five position switch. The switch, in turn, is electrically connected to a Spectrum Analyzer or Decibel meter. By selecting different switch positions each of the pick up coils can be individually tested without moving the electronic apparatus.

Abstract: A preprogrammed controller, preferably a stored program computer such as an IBM PC computer, is programmed to automatically control all the steps in the testing of a MR reproduce head. First, the magnitude of the sense current is established by command of the controller, and a voltage proportional to the sense current flowing in the head is monitored by the controller. An electromagnet, having high permeability pole pieces, and whose current is programmed by the controller provides a the magnetic field for exciting the MR head. The MR device is placed on an measured magnetic equipotential of the field of the electromagnet, and a Hall sensor magnetic detector is placed on the same magnetic equipotential line but in a different physical position from the MR device. The output of the Hall sensor is fed into the preamplifier electronics, digitized by a converter and this digital output is stored in the controller memory for future processing.

Abstract: A magneto-resistive tachometer includes an enclosure having a thickness of about 3/4", formed with a central through opening therein and a plurality of bolt holes sized and located for alignment with bolt holes on a standard NEMA C-type motor end face. The enclosure has a recess formed adjacent the central through opening and adapted to receive a sensor electronics package, and a radial slot formed between the central through opening and the recess for receiving a sensing element. An associated sensor drum has a peripheral surface with encoded sensor patterns thereon adapted to be sensed by the sensing element, and a center hub connected to the peripheral surface by a plurality of spokes. The center hub is adapted for clamping engagement with the output shaft of the motor within the center opening of the enclosure, in radially adjacent position relative to the sensing element. At least one of the spokes is provided with shaft clamping means for securing the drum to the output shaft of the motor.

Abstract: An ultrasonic position detecting device on a linear drive. The drive element of the linear drive bears a magnet arrangement cooperating with an adjacently placed sensor device which comprises an acoustic wave guide of magnetostrictive material. The magnet arrangement possesses an axially magnetized, annular or disk-like magnet part and, adjacent to the same, a pole part. By selection of the design of the pole part it is possible to affect the course of the magnetic field of the magnet part in order to achieve an optimum state for the sensor device.

Abstract: A method for monitoring an area of the surface of the earth uses measurement probes arranged in a grid for determining the self-potential with respect to a base probe. The measurement probes are interrogated repeatedly. The earth resistance between measurement probes and the base probe is also measured repeatedly between measurements of self-potential. Potentials on the surface of an area of the earth can be determined precisely, independently of earth-resistance changes.

Abstract: Axial alignment detection apparatus for a shaft rotatable about an axis includes alignment indicating means rotatable by the shaft and comprising a plurality of detectable elements; and detector means for detecting the elements and alignment of the shaft as a function of the elements; the elements comprising at least one reference element and at least one alignment dependent element, wherein the reference and alignment elements have a detectable alignment dependent relationship to each other.

Abstract: A method and apparatus for determining the distance and direction to a borehole containing ferromagnetic material includes placing a sensor package in a second nearby borehole and measuring three vector components of the static magnetic field perturbations of the earth's magnetic field caused by the ferromagnetic material. The sensor package is moved within the second borehole to obtain a plurality of magnetic field measurements, and the measured components are then projected onto a system of fixed coordinates whose orientation in space is known. The relative direction from the second borehole to the first is determined from the vector components, and the magnitude of the resultant in the direction of the first borehole is then determined from the fixed coordinate system.In a modification, the sensor package includes two spaced magnetometers for measuring vector components of the magnetic field perturbations.

Abstract: An assembly, and an associated method, locates selected wires positioned amongst a plurality of wires in a wiremat. An oscillating signal is applied to the selected wires; all other wires are connected to an electrical ground potential to minimize effects of capacitive coupling. A sensing probe is positioned amongst the plurality of wires of the wiremat and a constant magnitude, variable frequency annunciation signal is generated having a frequency which varies corresponding to the proximity of the sensing probe to the selected wires.

Abstract: An H-field probe for a radiation measuring system includes pairs of symmetrical planar magnetic loops for detecting electromagnetic (EM) radiation. EM radiation induces E-field and H-field currents in the loops. The individual loops of each pair are electrically coupled such that the E-field induced currents cancel while the H-field induced currents combine. The symmetrical construction results in virtually complete discrimination of the E-field.