Abstract: The invention relates to an actuator comprising a motor (4) by which the shafts (1, 5, 7) of the actuator are driven. At least one magnet (20 is arranged in conjunction with the shaft (1, 5, 7). The actuator further comprises at least one Hall sensor (3), which generates pulses as the magnet (2) on the shaft (1, 5, 7) passes the Hall sensor (3) as the shaft (1, 5, 7) rotates. The pulses are used to define the position of the actuator in the linear direction.

Abstract: A speed sensing seal with a first support member, a second support member, a magnetic elastomer member, a sensor member and an elastomeric seal member is disclosed. The magnetic elastomeric member with alternating adjacent poles is formed on the first support member and the sensor member is attached to an aperture in the second support member and overmolded with a layer of elastomer. The first and second support members are formed in the unitized body to form an internal cavity which contains the sensor, magnetic member, and the elastomeric seal. The first support member has a low wear surface to reduce initial seal failures and to enhance seal life.

Abstract: A magnetic position detector includes a soft magnetic target wheel, a magnetic sensor and a permanent magnet. The invention includes magnetoresistive sensors in several geometrical configurations of the target wheel, the sensor and the magnet. All configurations result in a big change of direction of the magnetic field at the location of the sensor as a result of a rotation of the target wheel. The configurations have in common that the direction of the magnetic field at the location of the sensor, as generated by the permanent magnet, is predominantly in the plane of the sensor surface, both when the sensor is next to a slot and next to a tooth of the target wheel, the surface of the sensor being substantially normal to the direction of movement of the target wheel.

Abstract: Systems and methods are provided for determining subsurface formation properties using an antenna system disposed within a borehole traversing the formation. A logging system includes a well tool implemented with an antenna system having transverse or tilted magnetic dipoles. One antenna implementation uses a set of three coils having non-parallel axes. Through mechanical or electromagnetic rotation of an antenna about its axis in order to maximize or minimize couplings, the systems and methods are used to estimate formation anisotropic resistivity, providing reduced borehole effects in vertical and small deviation wells. This invention may also be applied in deviated wells when the borehole is perpendicular to the strike direction, as is often the case in wireline logging.

Abstract: A method is disclosed for the determination of the dip angle of anisotropic earth formations surrounding a wellbore. Electromagnetic couplings among a plural of triad transmitters and triad receivers are measured. Each triad transmitter/receiver consists of coil windings in three mutually orthogonal axes. The transmitter coils and receiver coils are oriented such that mutually symmetrical transmitter pairs or mutually symmetrical receiver pairs are equidistant from a centrally located receiver or transmitter, respectively. The measured signals from the created couplings are used to generate initial separate estimates of the dip angle of the formation. The two discrete determination is of dip angle are then averaged to arrive at a more accurate estimate that approaches the true dip angle in the formation.

Abstract: A fixed magnetic sensor (16) is used to determine absolute angular position of a turning component (3, 4). A detection device (27) detects an angular position of a multipole magnetic ring (11) near a reference angular position. A resetting device (28) resets the angular position of the multipole magnetic ring (11) detected by detection device (27). The resetting device (28) is capable of assigning a value called “offset” to the value of the absolute angular position of the multipole magnetic ring (11). A determination device (29) determines the absolute angular position of the multipole magnetic ring (11) on all of the turns made by a turning component (3, 4) ascertained from the offset value and variations in the angular position.

Abstract: A magnetic sensor having a simple structure and high accuracy for detecting a linear or angular displacement thereof. A magnetic plate with tapered thickness is magnetized in a direction perpendicular to its surface. A magnetic sensor is arranged so that it can move in the direction of the taper of the plate thickness. A drive mechanism for this magnetic sensor is movable with an object to be detected, and the output of the magnetic sensor indicates the displacement.

Abstract: A pulse signal generator comprises a detecting assembly including a magnetic element wire (5) and a coil (2) wound around a bobbin (6) to generate electric pulses and a waveform shaping circuit integrated with the detecting assembly so as to shape the waveform of the electric pulses to output a pulse signal.

Abstract: Most mines and underground facilities employ standardized construction techniques and materials. Such also cannot avoid having some above ground openings to receive utilities, fresh air, supplies, etc. Those or other surface openings are also universally used to discharge ground water, wastes, and other materials. Typical underground facilities have abundant electrical wiring and power demands, both of which can be detected at the surface. Levees with leakage pathways also form electrical conductors. When properly illuminated with remotely generated electromagnetic (EM) radiation, many of these features will “glow” or reradiate the radio energy in an electronic signature unique to the underground facility. Synchronized EM-gradiometer transponders are situated nearby on the ground surface to collect and analyze the “glow”. Alternative transmitting devices further includes ways to generate the illumination, and computers for characterizing the return signatures.

Abstract: An embedded eddy current inspection apparatus includes a substrate having an opening, and a test eddy current coil (“test coil”) affixed to the substrate near the opening. An internally inspected multilayer component structure includes an upper layer, a lower layer, and an eddy current probe embedded between the upper and lower layers. The eddy current probe includes the test coil facing a subject layer selected from the upper and lower layers. A method of inspecting a multilayer component structure includes simultaneously energizing the test coil and a reference eddy current coil (“reference coil”) embedded between the upper and lower layers and facing the subject layer. The reference coil is located in a reference region of the multilayer structure. A test signal from the test coil is compared with a reference signal from the reference coil, to determine whether a flaw is present in the subject layer near the test coil.

Abstract: A proximity sensing assembly for sensing the proximity of a metallic workpiece to a work holding device includes Hall-effect sensor. The magnetic field generated by the magnet is altered when a metallic workpiece is in close proximity to a magnet. Due to an offset relationship between the sensor and the poles of the magnet, the polarity detected by the Hall-effect sensor is analogous to a reversal when a metallic workpiece is proximate the magnet rather than simply detecting a change in strength. Thus the polarity detected by the Hall-effect sensor sends a clearly defined signal indicating the presence or absence of a workpiece in the work holding device.

Abstract: A method of calibrating the magnetic coils of a magnetically enhanced reactive ion etcher includes taking magnetic field measurements outside of a closed plasma chamber and correlating such measurements to the magnetic field within the chamber. One or more factors are established which when applied to measurements taken externally yield results representative of measurements taken internally.

Abstract: Eddy current inspection of a contoured surface of a workpiece is performed by forming a backing piece of flexible, resiliently yieldable material with a contoured exterior surface conforming in shape to the workpiece contoured surface. The backing piece is preferably cast in place so as to conform to the workpiece contoured surface. A flexible eddy current array probe is attached to the contoured exterior surface of the backing piece such that the probe faces the contoured surface of the workpiece to be inspected when the backing piece is disposed adjacent to the workpiece. The backing piece is then expanded volumetrically by inserting at least one shim into a slot in the backing piece to provide sufficient contact pressure between the probe and the workpiece contoured surface to enable the inspection of the workpiece contoured surface to be performed.

Abstract: A metal locating system includes a first transmitter unit and a second receiver detector unit for locating an under and above ground radio frequency driven element such as a pipe. The first unit is a radio frequency transmitter operating at radio frequencies and coupled to the driven element as a loss line antenna. The receiver second unit is a switched diversity antenna connected to a radio FM receiver and a differential phase detection system. When the first unit is driven by the driven element, the second unit is able to detect and trace the position of the driven element relative to the switched diversity antenna.

Abstract: The invention relates to a method for substantially temperature-independent detection of the position of a moving element (9) by way of an inductive position sensor (1), comprising a coil (5) and a core (4) movable within the coil, the position of said core in relation to the coil (5) being dependent on the position of said element (9), whereby a measurement of the inductance of said coil (5), corresponding to the core (4) position, is detected by connecting a voltage to said coil (5) and measuring the time period in which a current (i) through the coil (5) is changed between two predetermined levels. The method follows the steps of feeding a regularly alternating voltage to the coil (5), measuring the current (i) flowing through the coil (5), measuring the period of time (t1) needed for the current (i) to change from a first predetermined level (i1) to a second predetermined level (i2), and determining a measurement of the core (4) position through measuring the period of time (t1).

Abstract: Apparatus for detecting a metal object comprises a transmitter for generating a pulsed or an alternating magnetic field in the vicinity of the metal object to be detected and a detector for detecting the secondary magnetic field induced in the metal object by the transmitted magnetic field. The detector measures at least three magnetic field gradient components of at least first order of the secondary magnetic field. The apparatus also comprises a processor for determining at least one of the position or the electro-magnetic cross-section or an estimate of the shape of the metal object from the measured magnetic field spatial gradient components. The processor fits the measured components to dipole, multiple dipole, multipole, or extended source models. In a preferred embodiment, the invention may comprise three or more pairs of gradiometric coils, or other sensing means.

Abstract: A sensing system for measuring the angular displacement of a rotating shaft is disclosed. The sensing system comprises a rotor and a sensor assembly disposed within the rotor. The rotor is constructed and arranged to be securably mounted to the shaft such that the rotor rotates in concert with the shaft. Furthermore, the rotor defines a plurality of teeth extending radially inwardly towards a center of the shaft. The sensor assembly comprises a sensor housing and a magnet arrangement disposed within the housing. The magnet arrangement defines a magnetic flux path between the sensor assembly and the rotor. As a result, the magnet arrangement and the rotor cooperate to define a magnetic circuit. Changes in magnetic flux through the magnetic circuit can be measured to determine the angular displacement of the rotating shaft.

Abstract: A buried closure guard has an electronic transponder attached to a flat, perforated carrier sheet constructed of a flexible polymer. Holes in the carrier sheet, which serve to anchor the guard, preferably have an effective diameter of at least about 1½″ to allow typical backfill materials to pass through. By providing a webbed carrier, any protrusion of a digging tool (such as teeth on a backhoe bucket) will catch on one of these holes and pull at the carrier to make it further visible during excavation. The perforated construction of the sheet allows backfill material to settle and pass through the carrier without significantly shifting or bending the carrier. The carrier also makes it easy to manually deploy the transponder, i.e., maintain a proper horizontal orientation of the transponder coil.

Abstract: A device for measuring the thickness of films or coatings on bases wherein the film thickness is determined from the magnetic adhesive force of a permanent magnet on the surface of the film to be measured. The device includes a permanent magnet attached to an end of a lever arm mounted at its center of gravity, forming a rotary system which includes an electromagnet counterbalancing the permanent magnet. The magnetic adhesive force between the permanent magnet and film is overcome by the variable force of the magnetic field of the electromagnet acting on the lever arm of the rotary system, the value of which, as the permanent magnet is lifted off the film, is used as a measure of the film thickness. In the best mode of operation, this is accomplished by integrating the time required to raise the current applied to the electromagnet to the value which generates a magnetic field which overcomes the adhesive force between the film and permanent magnet.

Abstract: An angular position sensor assembly for a vehicle generator shaft includes one magnet and three magnetic field sensors placed within a housing. The sensors are disposed on a circuit board that is parallel to the end of a generator shaft. The sensors are configured so that signals from the sensors are out-of-phase by predetermined angles. The generator shaft alternatingly forms plural slots and plural teeth. As the shaft rotates, the slots and teeth cause a change in a magnetic field around each sensor. By sensing the changes in the magnetic field, the position of the shaft can be determined from the out of phase signals received from the sensors.