Abstract: An apparatus for handling an object such as fruit having a major axis, includes at least one roller and a drive unit. The roller frictionally engages the object. The drive unit rotates the roller at a speed sufficient to cause the major axis of the object to be reoriented in a predetermined direction. This facilitates measuring the size and density of objects in a consistent manner.

Abstract: A prior art computerized ultrasonic examination is performed by moving an ultrasonic probe over the surface of an object, transmitting short pulses of ultrasonic energy into the material. Combined digital position and echo pulse signals are electronically stored, processed, and used for the display of a first video sectional flaw image of a selected sectional plane through the object. Representatives of reflected echo amplitudes from a chosen location are now shown, either in said first flaw image, or in at least one separate sectional view, as lengths of line segments originating at an image pixel representing said location, and drawn in the directions of the projections on said selected sectional plane of the incoming pulses at said location. In typical examples it is demonstrated, how reflected waves can be visualized and evaluated, and how the corresponding flaw images can be superimposed on said first video flaw image, thereby adding important information which is normally disregarded in the prior art.

Abstract: An ultrasonic rotational speed sensor in which all of the various electronic devices of the sensor are arranged compactly on one side of a rotational member to be measured, while maintaining a high precision in a rotational speed measurement. In this sensor, the transmitter microphone and the receiver microphone as well as other electronic devices associated with them are arranged on the same one side of the rotational member, where the rotational speed of the rotational member is determined from a period of the ultrasonic signals transmitted from the transmitter microphone, reflected at non-notch portions of the rotational member, and received by the receiving microphone, while a direct transmission from the transmitter microphone to the receiver microphone without an interaction with the rotational member is prevented by the use of a high frequency ultrasonic signals at MHz level.

Abstract: An ultrasonic contact transducer for point-focussing surface waves having a narrow beam width and a high sound intensity at a focal point in order to obtain better resolution and high beam intensity, which is applicable to the nondestructive testing technique of the surface or subsurface of a specimen to be tested, is disclosed. The ultrasonic contract transducer generates surface waves, focuses the waves at one point on the surface of the specimen and receives again the signals scattered from the surface flaws or subsurface flaws of the specimen, in order to detect the surface cracks, surface flaws, subsurface flaws of the specimen and to detect the delamination in a thin laminated film.

Abstract: An ultrasonic tube inspection system capable of rapid changeover for inspecting tubes of different diameter sizes includes a serial arrangement of multiple separate inspection stations. One inspection station is used to inspect for tube dimensions irrespective of the tube diameter size. The other inspection stations are used to inspect for flaws and are employed for different ones of the tube diameter sizes to be inspected. A set of ultrasonic transducer assemblies is supported at each inspection station. The transducer assemblies at the flaw inspection stations are in proper orientations corresponding to the diameter sizes of the particular tubes to be inspected at the respective inspection stations without the need for readjustment. The inspection stations contain quantities of liquid for coupling ultrasonic energy between the ultrasonic transducer assemblies and the tube passing through the inspection stations.

Abstract: A high-damping probe capable of obtaining not only sound velocity information but also other ultrasonic information useful for ultrasonic testing, such as the frequency and amplitude of the received wave, and also capable of increasing the accuracy of ultrasonic testing of structures made of concrete or other materials. The high-damping probe includes a transducer having a low-frequency damper attached thereto. By virtue of the above-described arrangement, the transmission wave will not oscillate for a long period of time and it is therefore possible to clearly discriminate between the transmission wave and the received wave. Since the received wave can be distinctly separated from the transmission wave, it is possible to obtain ultrasonic information such as the frequency and amplitude of the received wave. Further, it is possible to impart wide-band frequency characteristics to the probe, so that it becomes conformable to an ultrasonic testing device wherein the transmission frequencyt is variable.

Abstract: The method of ultrasonic inspection of welds of articles, wherein planes (3, 8) of polarization of transverse ultrasonic oscillations radiated into a weld (4) of an article (2) and of these oscillations registered upon their reflection by the reflecting surface of a flaw (6) of the weld (4) are set relative to each other at an angle 2.delta., an angle .xi..sub.1 between the plane (3) of polarization and a plane (5) of incidence of ultrasonic oscillations upon the reflecting surface and an angle .xi..sub.2 between the plane (8) of polarization and the plane (5) of incidence being selected substantially equal to 70.degree., thus providing for extracting from the radiated ultrasonic oscillations their component polarized horizontally with respect to the reflecting surface of the flaw (6), the amplitude of which is employed to estimate the geometrical parameters of the flaw (6), while the time of its registration is used to estimate the location of the flaw (6) in the weld (4).

Abstract: A device is disclosed for measuring the variation of the distance separating the two faces of a layer of solid material by means of ultrasounds, comprising:a generator generating a first alternating electric signal,an electroacoustic transmitting transducer,first coupling means for applying the ultrasonic wave to said layer of material,an electroacoustic receiving transducer,second coupling means for applying said ultrasonic wave to said electroacoustic receiving transducer,means for continuously measuring the variation of the phase-shift of the electric signal emitted by the receiving transducer with respect to said first alternating electric signal, andcomputing means for deriving said distance variation from said phase-shift variation, wherein:said electroacoustic transmitting and receiving transducer, as well as said first and second coupling means are disposed on the same side of said layer of material, andsaid first and second coupling means are solid ultrasonic wave-guides.

Abstract: A hand-held ultrasonic probe for measuring the thickness of a conduit, such as a boiler tube, from the tube inside surface. The probe is slidable and rotatable relative to the longitudinal axis of the tube under investigation. The probe may also be manually skewed relative to the tube longitudinal axis to measure corroded regions which are not parallel to the centerline of the tube.

Abstract: Ultrasonic thickness measurement of layers of paint on a substrate produces pulse echoes indicative of each layer interface. Several ultrasonic waveforms are averaged in a digital oscilloscope and the resultant waveform is analyzed by a computer programmed to recognize wave forms resembling pulse echoes, compare such waveforms to stored reference waveform characteristics, and selecting the waveform having the best fit to the reference. Each selected pulse echo is graded based on amplitude, peak separation, peak symmetry, and spacing from a previous echo to determine the quality of the waveform. Layer thickness is calculated from the spacing between pulse echoes and the velocity of sound in the layer material.

Abstract: An apparatus for determining the magnitude of heart muscle contractions has two ultrasonic transceivers, both of which are disposed in sonic alignment on selected points of the heart. A digital counter electrically interconnects the transceivers with a digital microprocessor. The counter determines a pulse transit time which corresponds to the difference in time between the transmission of a sonic pulse from the transmitter and the reception of the sonic pulse by the receiver. Immediately after determining each pulse transit time, the counter sends the transit time signal to the microprocessor, which first filters the signals to reject any signal which indicates a heart size that is unreasonably large or small. After filtering, the transit times are averaged in groups of a predetermined number and then converted to corresponding heart size measurements for storage and display.

Abstract: According to the method of the invention concerning tubes, of which the plating to be checked is at least 0.4 mm thick and in which the acoustic impedance differs by at least 1% relative from that of the core of the tube, a properly dampened transducer is selected which has a frequency of 4 to 10 MHz. The position of the transducer in respect to the tube is adjusted experimentally, and its parameters of distance and orientation are differently adjusted in order to increase the "signal-to-noise" ratio. For determining the thickness of the plating, at least one double echo from the interface between the plating and the tube core is used, or alternatively, a triple echo from this interface. Also, there is a corresponding ultrasonic measuring apparatus as well as an application of the method to the ultrasonic measuring of the thickness of the plating of Zr alloy tubes. The tubes are plated with non-alloyed Zr or with some other Zr alloy.

Abstract: A method and an apparatus for ultrasound imaging at different frequencies using a single ultrasound transducer. The transducer has a single characteristic frequency. The method and apparatus involve driving the transducer with pulses having different rise times through different coupling circuits having different impedance characteristics. Between pulses, the same transducer and coupling circuit which were used during the pulse transmission "listen" for echoes from the structure being ultrasonically investigated. It is believed that the combination of different pulses having different rise times and different coupling circuits having different characteristics enhances different ones of the frequencies contained in the Fourier spectrum of the driving pulse and suppresses others. This enables the operator to investigate a structure ultrasonically with a single transducer at different frequencies which illuminate different characteristics of the structure to greatest advantage.

Abstract: An ultrasonic sound echography technique is disclosed in which echo-masked zones of the workpiece are reduced by utilizing particular orientations of the beam of ultrasonic sound relative to formations in the workpiece. Echo-masked zones result from formations in the workpiece which reflect the ultrasonic sound waves back to the probe and therefore mask the much smaller echoes from anomalies, if any, in the workpiece. Instead of the conventional orientation of the beam, in which the scanning plane in which the beam lies is oriented perpendicularly to formations, the scanning planes are selected so as to be non-perpendicular with respect to such formations and to minimize the amount of masking echoes from the formations.

Abstract: A method and apparatus for measuring the quantity of bubbles in a gas/liquid mixture. An ultrasonic wave is launched into the mixture and the magnitudes of two reflected waves are measured and compared. The logarithm of the magnitudes of the reflected waves is a measure of the quantity of gas content. The method and apparatus are suitable for measuring gas bubble content repetitively in a mixture turbulently flowing through a conduit.

Abstract: An apparatus for determining the depth of cracks in the surfaces of workpieces includes an ultrasonic transducer for sending ultrasonic signals to and receiving ultrasonic signals from the workpiece, an analyzer connected to the ultrasonic transducer for forming a frequency spectrum from the ultrasonic signals, an evaluating unit connected to the analyzer for determining an effective band width correlated with the depth of the cracks in the workpiece as the quotient of the integral of the frequency spectrum and the ordinate value of the center of concentration of the integrated surface of the frequency spectrum, and an indicator connected to the evaluating unit for indicating the depth of the cracks.

Abstract: An apparatus and method of non-contacting, non-destructive, on-line dimensional analysis and flaw detection of tubular products are disclosed. The apparatus includes penetrating radiation sources and detectors arranged about the product to be examined and a high-speed data processing system which employs novel computed tomography techniques to provide high precision dimensional estimates and flaw detection. The apparatus is capable of continuously determining the outside diameter, inside diameter, wall thickness, ovality, eccentricity, and weight-per-foot over a wide range of temperatures for essentially tubular products produced on a unit or continuous basis. The apparatus can also detect process-induced flaws in the products.

Abstract: The air gap between a rotor and a stator in rotating electrical machinery is determined using sonar techniques. An ultrasonic signal transmitter and receiver are mounted on one of the rotor and stator for transmitting ultrasonic signals to the other of the rotor and stator and receiving reflections therefrom. The time between signal transmission and reflected signal reception is determined, and the spacing of the rotor and stator is determined from the time, the velocity of sound, and the speed of rotation of the rotor.

Abstract: System for monitoring containers with ultrasonic seals.According to the invention the seal is duplicated and comprises a transmitting transducer and a receiving transducer. The exciting signal is a voltage step applied to the transmitting transducer and the circuit able to supply said step is directly connected to the transmitting transducer without a connecting cable.Application to the monitoring of containers containing dangerous products, precious materials, documents, etc.

Abstract: Method and system for detecting defects in the structure of a composite laminate material are described which comprise a first transducer for directing an ultrasonic beam of preselected frequency along a transmission axis onto a surface of the laminate at a preselected angle to generate Lamb waves in the laminate and leaky Lamb waves reflected therefrom; a second transducer for detecting the reflected leaky Lamb waves and for providing an output signal corresponding to the amplitude of the reflected waves; a fluid sonically coupling the laminate with the transducers; a positioning system for selectively positioning the transducers along the surface of the laminate to produce a set of output signals characterizing the laminate; and suitable electronics for receiving and processing the output signals and comparing them with signals characteristic of a defect free sample of the laminate.

Abstract: A transmitting ultrasonic transducer (20) is excited by high-frequency pulses from a high-frequency pulse generator (1), a leaky elastic surface wave is excited in a sample (6) by a focused ultrasonic beam from the transducer (20), a reradiated wave of the leaky elastic surface wave is received by a receiving ultrasonic transducer (24), the received signal is applied to a mixer (23), wherein the phase difference between the received signal and a reference signal from a high-frequency oscillator (18) in the high-frequency pulse generator (1) is detected, and the detected output is provided as a display signal to a display (9 or 14). The transducers (20) and (24) and the sample (6) are moved by a drive means (7 or 10) relative to each other two-dimensionally in a plane parallel to the sample surface or in a direction perpendicular to the sample surface, and in synchronism with the movement, the display screen of the display (9 or 14) is swept, displaying thereon an ultrasonic microscopic image or a V(z) curve.

Abstract: An ultra-sonic distance sensor system includes means for measuring the elapsed time between transmission of ultra-sonic waves and receipt of the return wave reflected by an object which reflects ultra-sonic waves and the distance to which is to be measured. A correction value is derived on the basis of the rate of change of the signal level of a receiver signal output by an ultra-sonic receiver. On the basis of the derived correction value, the resultant distance value or the measured elapsed time value is corrected to ensure accurate measurement of the distance to the object can be ensured. This allows more precise height control for a vehicle when the distance detector is applied to a height control system of an automotive vehicle.

Abstract: Method and apparatus for nondestructive inspection and detection of flaws in a workpiece according to four techniques is disclosed. Elastic waves are thermoelastically or electrodynamically induced in a workpiece by electric current energization of an elastic wave inducing source adapted to be disposed in contact with the workpiece remote from a defect. An acoustic sensor is disposed in elastic wave transmitting contact with the workpiece remote from the source and produces an output signal having an amplitude representative of received elastic waves. The presence of a crack, flaw or defect in the workpiece is detectable as a variation in the amplitude or other characteristics of the acoustic sensor output signal.

Abstract: The softness of paper as a function of the number of bonding sites per unit area of the paper is determined by directing ultrasonic energy toward the paper and determining the magnitude of the portion of reflected energy.

Abstract: In the method and installation for determining a relative distance between the front wall (22) of the cylinder and the piston (14), an ultrasonic converter (30) is used to which a plate (68) presenting a reflecting reference surface (66) for the formation of a reference path is secured. The group of reference oscillations (R) and the group of measurement oscillations (M) appearing in the output signal of the converter (30) after the emission of a group of transmitter oscillations (S) are detected by means of threshold switches (108, 120, 122). Thereby, a measurement signal and a reference signal are obtained, the latter being used for compensation by means of a processor (38) for the influence of the different propagation conditions affecting the measurement signal.

Abstract: A method of identifying and determining the size of particulates in a flowing fluid comprising detecting the portion of an ultrasonic pulse scattered from a particulate at a preselected angle, converting the results into density and elasticity-related values and comparing the values with measured or computed values for known particulates.

Abstract: For the detection of defects such as tears or fold lines in banknotes, for example, continuous wave ultrasonic energy is directed by a transmitter to a flow path for the notes and ultrasonic energy reflected from the notes or transmitted through tears or holes in the notes is converted by a receiver into an electric signal. A signal analyzing circuit is responsive to changes in the output of the receiver during the passage of the banknote. In the ultrasonic inspection area, the note may be passed over rollers with flared ends to cause a tear to open and allow the passage of ultrasonic energy. In a reflective system the note may be passed over a roller to cause one or both of the adjacent edges of a tear to leave the roller surface. The electric signal is analyzed for components indicative of a defect; for tear detection, a spike filter and a circuit for distinguishing tear signals from end-of-note signals may be used.

Abstract: The invention relates to an ultrasonic test instrument, in which a receiver amplifier is controlled in dependence upon time by means of a depth compensation signal or else the ultrasonic signal amplified independently of the depth is evaluated by means of a time-dependent variable threshold signal. The depth compensation signals and the time-dependent threshold signals are derived from the same digital signal values stored in a main memory. The test instrument comprises a microprocessor by means of which the digital signal values for each material requiring testing are automatically measured by the instrument itself in conjunction with whichever test probe is used provided a corresponding test block of this material is available.

Abstract: An ultrasonic transmitter (10) and at least two ultrasonic receivers (12, 16) are mounted on a carrier (18) which traverses the surface (22) of a solid material (24). The sound beam (30) from the transmitter (10) passes beneath the surface (22) and enters a zone of interest disposed about a point (36) located a fixed distance (40) beneath the surface (22). Reflected sound beams (42, 46) emanating from flaws (54, 58, 60) located within the zone of interest are detected by the receivers (12, 16). The orientation and positioning of the transmitter (10) and the receivers (12, 16) for maximizing the detection and differentiation of the detected flaws (54, 58, 60) are also disclosed.

Abstract: Low pressure turbine disc rims are inspected by a method in which an ultrasonic beam is directed into a disc rim steeple from a location on the disc rim web. Reflected waves are received and signals indicative thereof are produced for display. A predetermined time window is established on the display, based on the time-of-flight difference between the top of the steeple and the disc rim. The presence of signals within the time window on the display is determined to indicate the presence of a crack. Cracks located along the steeple serrations and oriented in a generally tangential direction to the steeple cross section are detected by producing an ultrasonic beam directed along a line normal to the bottom of a steeple. Cracks located at the bottom of a blade groove at the steeple root and oriented in a generally radially direction can be detected by producing an ultrasonic beam skewed at an acute angle relative to the line normal to the bottom of a steeple.

Abstract: The invention is useful in the field of diagnostic ultrasound to improve the axial resolution of an image. One embodiment comprises a transmitted, ultrasonic wave with two parts. The first part interacts with a specimen to initiate an echo, and the second part arrives out-of-phase with the ringing of the specimen and interferes to suppress the ringing. Another embodiment comprises a transmitted, electrical signal with two parts which interact as described above to cause a piezoelectric transducer to produce a transmitted, ultrasonic wave with truncated ringing.

Abstract: This invention relates to ultrasonic test instruments using wide-band test probes of different nominal frequencies fo and discloses an arrangement wherein each wide-band test probe of different nominal frequency fo is coupled in circuit with a receiving amplifier having a frequency response V(f). The frequency response of the receiving amplifier is so selected that the product H(f) comprising the spectral distribution S(f) of the transmitter and the frequency response V(f) of the receiving amplifier is substantially constant approximately up the the nominal frequency fo of the test probe and has its maximum value in that range. For the transmitters conventionally used in ultrasonic test instruments, in which the transmission pulse is generated by a capacitor discharge, the frequency response V(f) of the receiving amplifier should have a linear rise of 6 dB/octave up to approximately the frequency fo.

Abstract: A programmable ultrasonic thickness and acoustic velocity measuring instrument is provided which includes automatic zeroing (calibrating) means, automatic temperature compensation and high temperature warning means, automatic probe identification means, means for automatically correcting the measurement readings for probe characteristics, means for storing and displaying of the minimum wall thickness during a predetermined time interval, and means for providing a display indicative of the difference between a measured thickness and a preprogrammed value.

Abstract: An ultrasonic inspection apparatus for inspecting a test piece includes an ultrasonic transducer for transmitting test signals into the test piece, for receiving associated response signals reflected back thereto, and for generating a defect signal when a response signal indicates an abnormal condition in the test piece. A control signal generator generates a control signal at predetermined intervals of distance of movement of the transducer relative to the test piece while the transducer generates test signals at a frequency independent the control signal frequency. A principal counter counts the control signals and generates an alarm signal when its count exceeds a value indicating that sufficient defect signals have been generated during movement of the transducer over a predetermined distance to confirm the presence of an unacceptable abnormal condition.

Abstract: In a method for ultrasonically measuring the thickness between opposed surfaces of a workpiece from one surface, a velocity parameter of ultrasonic longitudinal waves through the material of a workpiece is measured at a location along a first surface of the workpiece. Ultrasonic longitudinal waves are transmitted from one surface to the opposite surface, and the ultrasonic waves reflected from the opposite surface are received and a time parameter between transmission of the longitudinal waves and reception of the reflected waves is measured. The thickness between the opposed surfaces is determined from the measured velocity parameter and the measured time parameter. A device for measuring the thickness of a workpiece from one surface includes a transducer assembly with a pair of spaced apart transducer units each having a coupling member and a piezoelectric element mounted thereon.

Abstract: Methods and apparatus for calibrating terminated ultrasonic electroacoustic transducers are disclosed. The transducers are excited by a driving signal to emit an ultrasonic acoustic wave, which wave is received either by the same transducer after reflection or by a second transducer to produce an output signal. The driving signal and output signal are supplied to measuring circuitry deriving transdBACKGROUND OF THE INVENTIONThe invention described herein was made in the course of work under a grant or award from the Department of Health, Education and Welfare.

Abstract: A pit depth gauge for use as an accessory to an underwater ultrasonic probe omprises two resiliently biased, freely flooded telescoping members a first of which has a first end wall adapted to ride on a surface to be inspected and a second of which has a second end wall adapted to be connected to the probe with the probe transducer in registration with an acoustic energy port. A stylus is fixed to the second member for axial movement with the transducer toward the first end wall as the stylus enters a pit, whereby the length of an acoustic water path is related to the pit depth.

Abstract: Electronically focused and automatically scanning acoustic bulk waves are produced by scattering chirp acoustic bulk waves at grazing incidence from an acoustic grating. The same apparatus may be used in reverse to convert diverging acoustic bulk waves produced by a focused beam into chirp acoustic bulk waves. A pulse compression filter then converts the chirp waves into signals describing the source.

Abstract: An ultrasonic thickness meter provides one or both of two improved operational facilities. The first enables the meter probe to be zeroed at will to allow for the acoustic transit time of the stand-off material of the probe. The second enables the operator at the flick of a switch to display the difference `plus or minus` between the thickness of a workpiece being measured and that of a set standard. The meter includes means to duplicate the acoustic transit time of a zero block or standard block electronically as a first time value signal and to set up a second time-value signal representing the time from excitation of the transmitter crystal to receipt of the first return echo from the far side of the zero block or standard block. These time-value signals are combined under the control of manually operated switches to zero the probe or offset the probe to the set standard.

Abstract: An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

Abstract: A method and apparatus for investigating a rod-like body which is anchored in a surrounding material and which has an accessible end, for determining the state of the anchorage of the body and its length. Transient elastic oscillations are excitated in the accessible end of the body. The oscillations comprise a flexural wave causing a deformation of the body varying with respect to amplitude and phase over the cross-section of the body. The flexural wave propagates in the longitudinal direction of the body and is partially reflected at discontinuities of the body and/or the anchorage. Transient elastic ocillations comprising flexural waves reflected at such discontinuities and returning to the accessible end of the body are received and detected. The position and magnitude and/or type of at least some of the discontinuities are estimated with the aid of time-position and amplitude of the reflected flexural waves.

Abstract: A nondestructive testing method of ultrasonic defect characterization based upon the separation in time-of-arrival between the reflected pulse and its leading diffracted satellite pulse in the case of a crack-like defect and its lagging scattered satellite pulse in the case of an inclusion-like defect is shown. The angle beam, single probe type, echo ranging technique differentiates the main defect reflection from the satellite pulses of the defect and uses the sequence and magnitude of the separation in time-of-arrival between the pulses to determine the shape and size of the defect. Due to a discovered linear relationship between the ultrasonic delay time and defect size, the time scale of an oscilloscope's screen can be adjusted to read directly in terms of crack depth or inclusion diameter. Beyond the need to recognize returning pulses, the relationship is independent of wave amplitudes and the technique is thus easily utilized and is compatible with many different types of materials to be tested.

Abstract: Welded joints of austenitic steels are tested by ultrasonic sound caused to be incident on the joint at an oblique angle thereto. Information regarding the size and nature of reflectors in the joint can be derived from the amplitude of the echoes generated at the reflectors in response to the sound beam. To ensure a definite relationship between the amplitude of the echoes and the nature and size of the reflector, the frequency of the sound use for testing is below and upper frequency limit at which the wavelength of sound in the base material equals the largest peak-to-valley distance of the base metal weld interface in any of the consecutive areas of the interface on which the sound beam is incident at any time.

Abstract: A way of automatically inspecting a machined part, for example, to a tolerance of 0.001 inches. A minicomputer monitors a change in phase of acoustic wave energy impinging upon a sample part and compares it with a change in phase of such energy for a standard or master part, any difference between the monitored changes being interpreted to determine if the sample is within acceptable tolerance limits. The inspection approach described uses no moving parts and can be used to inspect many dimensions of a part simultaneously in less than a second. Acoustic wave energy can be used to inspect parts of any shape. The inspection system disclosed can be used, as well, to monitor the geometry of an object over time to note any changes in said geometry. And the concepts of the inspection system can be employed in conjunction with robot-controlled devices to provide close-positioning data for such devices.

Abstract: Apparatus for use in conjunction with a work piece positioned on a work table and having an interface spaced from the work table which is provided for controlling the impingement of the beam from an electron beam welder upon the interface. A search unit coupled to the work table both generates a sense wave pulse along the work piece and receives an echo from the work piece interface. A timing circuit is operatively coupled with the search unit and determines the elapsed time between the generation of the sense waves pulse and the receipt of the echo from the interface so that the elapsed time is representative of the distance of the interface from the work table. In response to the elapsed time determined by the timing circuit, a control unit generates electrical signals to a deflection coil magnetically coupled with the electron welder beam to position the beam so that the beam impinges upon the work piece interface.

Abstract: Disclosed is an apparatus and method for nondestructive testing of structures where the apparatus includes a transducer for generating an ultrasonic acoustic signal, a nonlinear medium for parametrically generating a special, ramp, waveform, and an acousto-optic broadband receiver for detecting a reflected signal from the test structure. A homodyne interferometer is provided to measure the change of refractive index of the acousto-optic receiver, and generates an electrical signal representative of the reflected acoustic signal. Signature analysis techniques are utilized to evaluate the reflected waveform to determine the characteristics of the structural defects.

Abstract: Apparatus for use in the control of arc welding, especially the automatic ntrol of consumable electrode arc welding employs a technique of reflecting an ultrasonic pulse from that end of a strip of weld filler material which is melting into the weldpool. The time taken from transmission to return of the ultrasonic pulse is measured to provide a measure of the length of filler material projecting beyond the welding torch, which can then be used eg to facilitate automatic control of the welding process. Apparatus using magnetrostrictive and or magnetoelastic methods of ultrasonic pulse transmission and reception are described. Also apparatus using a piezo-electric method for pulse transmission and reception is described which is especially useful for a non-ferromagnetic weld filler strip.

Abstract: A method and apparatus for the ultrasonic detection of pipe cavity in hot slabs, blooms, and billets to determine the optimum cropping length. An ultrasonic transducer surrounded by a water-jacket for circulating a cooling medium is embedded in a blade of the crop shear of a primary mill. The pressure of the shear blade against the workpiece is utilized to create the proper acoustic couple between the workpiece and the transducer.

Abstract: An ultrasonic inspection system is disclosed which provides for penetration of highly attenuative materials by use of the longitudinal mode of particle vibration. Separate transmitting and receiving transducers, which are electrically isolated, are utilized in the inspection system as are specially designed transducer wedges producing refracted longitudinal ultrasonic waves.

Abstract: A system and method for detecting defects in composite laminate material are described which comprise a first trtansducer for directing an ultrasonic beam of preselected frequency and tone burst excitation along a transmission axis through a sonic coupling bath onto a surface of the material at a preselected angle to generate Lamb waves in the material and leaky Lamb waves reflected therefrom, a frequency modulator for selectively modulating the frequency of the incident beam, and a second transducer for receiving the reflected sonic field including leaky Lamb waves reflected from the material and for providing a recovered and envelope-detected output signal corresponding to the amplitude of the reflected waves.