Abstract: A high-frequency signal is applied from an oscillator via a circulator to a piezoelectric transducer. An ultrasonic wave generated by the piezoelectric transducer is directed to a material through an acoustic lens. The ultrasonic wave transmitted through the material is conducted to a phase-conjugator having a nonlinear piezoelectric element consisting of a crystal of LiNbO.sub.3. A phase-conjugate wave generated by the generating section is transmitted through the material again and received by the piezoelectric transducer. The received signal is supplied to a receiver circuit via the circulator. The receiver circuit gates the received signal in accordance with a time of return of the phase-conjugate wave so as to extract a signal representing the interior of the material. The material is scanned two-dimensionally by a scanning control device so as to display a two-dimensional ultrasonic image on a television monitor.

Abstract: A tube inspection station includes a receptacle having walls defining a cavity for holding energy coupling liquid and receiving an object to be inspected in the liquid. At least one wall of the receptacle has a longitudinal bore defined and extending therein from an opening at the top thereof above the cavity and a transverse bore extending through the wall. The transverse bore intersects with the longitudinal bore and opens at both interior and exterior surfaces of the wall. The station also includes a transducer operable for sending waves of energy from its first end into the cavity toward the object and receiving echos of energy at the first end from the object for measuring a parameter of the object. Also, the transducer is operable for transmitting input and output signals at its second end.

Abstract: The scanning device for ultrasonic control of articles comprises a suspension assembly (7) for mounting ultrasonic transducers on a motion mechanism (6) of the scanning device. The assembly (7), in its turn, includes flexible members (8) positioned above a surface (4) of an article (2) under inspection, having ultrasonic transducers (1) fixedly mounted thereon and contained within a housing (3), a beam (9) extending above the flexible members (8) and mechanically connected therewith, two self-aligning supports (10), each including two parts, that is, an arcuate member (16) and rollers (17) so arranged with respect to each other that their relative displacement takes place about a rolling axis (15) common to both supports (10), extending along the surface (4) of the article (2), and two rockers (11) operatively connected to the beam (9) and to the motion mechanism (6).

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: The present invention provides a method for ultrasonic measurement of mainly the depth of a flaw possibly existent in a solid mass and opening to the surface of the solid mass. An ultrasonic wave is transmitted into the solid mass by scanning an ultrasonic probe back and forth on the surface of the solid mass with respect to a flaw in the solid mass, a threshold of a predetermined level is set for a curve defined by levels of echoes of the ultrasonic waves reflected from the flaw according to the position of probe, the area under the curve and above the threshold is integrated for the range of movement of the probe, and the depth of the surface opening flaw is measured using as an evaluation index the value of the integrated area of the area. The method according to the present invention is applicable to nondestructive, easy, accurate and realtime measurement of the depth of weld cracking in a welded portion, fatigue cracks in a stress-concentrated portion of members of a machine, etc.

Abstract: An ultrasonic transducer assembly for monitoring the quality of spot welds employs a transducer element joined to a support element and fitted within a conventional welding electrode assembly. The transducer assembly is biased against the interior surface of the welding electrode tip by a biasing element, preferably a compression spring. A sleeve, preferably composed of brass, surrounds the transducer element and is joined to the support element. A coaxial cable in communication with external instrumentation has a ground lead attached to the sleeve, and a signal lead attached to the transducer element.

Abstract: A system and apparatus for ultrasonic pulse echo inspection of corners in laminated parts. A variable angle transducer including transducer, fixed reflector, and rotating reflector which effects scanning of the radial arc being tested by the sonic output from the transducer provides ultrasonic information which is processed through an ultrasonic signal processing system which digitizes, stores and displays the information.

Abstract: In an automatic ultrasonic testing method for automatically detecting an internal flaw of articles such as a solid-core station post insulator and a long-rod insulator in which ultrasonic noises are liable to be generated in ultrasonic testing waveform, use is made of a standard waveform having a plurality of maximum peak hold data in predetermined intervals at all the detecting points and obtained by detecting the normal article including the ultrasonic noises, with which ultrasonic testing waveforms of an article to be tested are compared. Therefore, it is possible to eliminate an instability of the ultrasonic testing waveform and to detect a flaw echo having a level lower than that of the ultrasonic noises.

Abstract: Apparatus for sensing the thickness of a pulp suspension, having zones or slices, on the forming wire of a paper making machine includes an array of ultrasonic transducers located in the apertures of a structural member mounted in a cross-direction under the forming wire near the headbox of the machine. Each ultrasonic transducer is mounted on a flexible sheet which is mounted to an aperture and the transducer moved into close proximity to the bottom of the forming wire by means of air pressure in the structural member. A second array of transducers downstream of the first can be utilized for diagnostics.

Abstract: An apparatus and method for achieving variable observations angles by a single transducer rotationally and pivotally mounted with a housing; and for utilizing the variable angle transducer to detect and trace and distance of unseen objects within a casing from the transducer by moving the transducer within its housing which is held stationary against the casing; and for determining the angle of observation between the transducer and the observed object; and thereby accurately determining the relative position and orientation of the object within the casing.

Abstract: A phase difference comparison type of ultrasonic velocity meter repeatingly transmitting acoustic waves in the form of pulses at alternate time intervals: T-T.sub.S and T+T.sub.S, receiving reflected waves generated by the transmission of these waves and reflected on an object, forming first and second mixed waves by mixing the reception signal obtained from the reflected waves with two reference waves having phases shifted 90 degrees from each other, detecting the phase difference between the present vectors representing the first and second mixed waves and similar vectors which have been obtained with respect to the preceding pulse transmission, detecting the phase difference Q between the phase difference caused in relation to the time interval T-T.sub.S and the phase difference caused in relation to the time interval T+T.sub.S with respect to a phase difference obtained each time a pulse is transmitted, and calculating the Droppler shift angle frequency .omega.d from .omega.d=Q/2T.sub.S.

Abstract: An acoustic inspection system includes acoustic transducers to transmit and receive continuous acoustic waves at a constant frequency. Changes in phase and/or amplitude of acoustic waves reflected at different times from a fixed reference target through an isothermal transmission medium are detected. The temperature of the acoustic transmission path is controlled in response to the detected phase changes to maintain the wavelength of acoustic waves constant independent of changes in humidity and barometric pressure.

Abstract: A microprocessor-controlled, hand-held, digital ultrasonic thickness gage having automatic zero calibration, scroll velocity adjustment and an electronic locking feature to prevent inadvertent calibration or velocity data variations. This invention is used with a dual-element transducer and, in that regard, employs a microprocessor program which automatically corrects for the well-known, inherent thickness gaging inaccuracies (nonlinearities) always caused by the use of the otherwise advantageous (high sensitivity) dual element transducer.

Abstract: An ultrasonic apparatus and method for testing a material comprises an oscillator which generates a selected frequency in the ultrasonic range. A transducer is connected to the oscillator for applying an ultrasonic signal to the material and for receiving an echo signal back from the material. Two phase detectors are utilized one of which receives the echo signal and an in-phase oscillator signal to generate a first display signal, and the other of which receives a quadrature signal which is 90.degree. out of phase from the oscillator signal, as well as the echo signal to generate a second display signal. The first and second display signals are utilized in a visual display such as a cathode ray tube, to generate an image. The image changes according to the phase shift between the ultrasonic signal transmitted into the material and the echo signal, which, in turn, can be utilized to determine the presence and depth of a flaw or boundary in the material.

Abstract: In an ultrasonic microscope, if a plane to be observed of a sample is not parallel with a scanned plane formed by an ultrasonic wave beam, an interference with a reflected wave will be produced and no clear picture image will be obtained. Therefore, it is indispensable to adjust the inclination of the sample stand as an initial adjustment before the observation.

Abstract: An ultrasonic probe for measuring the velocity of sound in a liquid consists of a tube (12), closed at its lower end, and arranged to extend into the liquid, a reflector (20) alongside the tube but spaced away from it, and a source (30) of ultrasonic waves in the tube. The source is arranged so as to cause an ultrasonic beam to propagate through the tube wall (16), to traverse the liquid occupying the space between the tube (12) and the reflector (20), and to be reflected back. The source (30) can be scanned along the length of the tube to ascertain the variation of liquid properties, the position of the liquid surface, and the presence of emulsion layers and precipitates. The wall of the tube through which the ultrasonic beam emerges may be plano-concave in cross-section to enhance the ultrasonic beam intensity in the liquid.

Abstract: An apparatus for examining objects by ultrasonic echography comprising an ultrasonic transmitting transducer (10) and an ultrasonic receiving transducer (20), with which are associated a transmitter stage (30), a receiver stage (40) constituted by a channel (100) for processing the echo signals reflected to the receiving transducer by the obstacles they meet in the said region and a storage and/or visualization stage (60), characterized in that the transmitting transducer (10) is at the same time a receiver and in that the receiver stage (40) also comprises a channel (200) for processing the output signals of the said transmitting/receiving transducer (10) thus formed and a subtraction device (500), whose output is connected to a first input (560) of the storage and/or visualization stage and whose two inputs receive the output signals of the said channels (100) and (200) representative of the real and theoretical travelling times, respectively, between the transducers.

Abstract: A method is disclosed for ultrasonically detecting and measuring oxide scale on the inner cylindrical surface of a fluid containing boiler tube, in situ, within a boiler. An ultrasonic pulse is directed into the tube. The time of flight of the ultrasonic pulse within the scale is determined. The determined time is correlated to the thickness of the scale.

Abstract: A circuit arrangement for separating high-frequency pulses produced successively in time at a piezoelectric transducer of an acoustic reflection lens arrangement. According to the invention, the transducer is preceded by a three-way pin switch, the common end of the wiper of which is connected to the acoustic lens, the other end of the wiper being alternately connected in a first position to the output of a transducer oscillator, in a second position to a 50-Ohm resistor, or in a third position to a measurement circuit.

Abstract: Ultrasonic testing device with a test head which includes an electromechanical transducer, especially a piezoelectric oscillator, with an ultrasonic equipment and with a shielded cable which connects the test head to the ultrasonic equipment. The test head has two electrically conducting shields which surround the transducer in cup-fashion. The two shields are connected to the outer conductors of the triple coaxial cable. The outer conductor of the cable is connected to a metal housing of the ultrasonic equipment and is grounded.

Abstract: A Compound echo-ultrasound imaging system in which the intensity of pixels in an image is a nonlinear function of the amplitude and frequency of echo signals. The dynamic range of a synchronous FM detector in the system is increased by effectively filtering from the echo signals all instantaneous frequencies which would produce intensity levels greater than a corresponding signal of equal amplitude at the carrier frequency of the ultrasound pulses. Filtering may be effectively accomplished by setting the Corner Frequency of the synchronous detector to the carrier frequency of the transmitted pulses.

Abstract: A method for the ultrasonic testing of bolts for incipient cracks emanating from a wall thickness discontinuity between thinner and thicker parts of the bolt, which includes placing an ultrasound transmitter and receiver in the form of a piezo-electric transducer on the periphery of the thicker part of the bolt with the discontinuity located in the near-field region, radiating longitudinal waves at an angle of 55.degree. to 70.degree. and transversal waves at an angle of 25.degree. to 35.degree. from the transducer in direction toward the discontinuity, and comparing the intensity of reflected transversal and longitudinal waves with an echo characteristic obtained from a test body corresponding to the bolt to be tested, having slots formed therein simulating incipient cracks of different depths, and an apparatus for carrying out the method.

Abstract: A method for evaluating echo signals transmitted and received by an ultrasonic transducer in a sensor of a movable mechanical element, such as an arm of an industrial robot, has the steps of receiving and storing the arriving echo signals in chronological sequence in a memory, the chronological sequence of the signal being converted into a corresponding sequence of memory positions, with successive sequences of echo signals of successive transmit pulses being stored in the same sequences of the memory positions. Integration of the echo signals of the successive sequences stored in the memory positions are undertaken such that the local shift of the ultrasonic transducer disposed on the moveable element which occurs between respective transmit pulses is compensated relative to chronologically adjacent pulses and the pulses reflected from a target are more easily identified.

Abstract: The non-destructive testing of solid bodies is conducted by generating a transverse, ultrasonic surface wave in the solid body being inspected, said surface waves having sufficient different frequencies such that they travel at different depths through the body being inspected; receiving at least a part of the reflected portion, if any, of the surface waves, the reflected portion consisting of at least two surface waves having sufficiently different frequencies such that these waves travelled at distinctly different depths through the solid body and filtering and measuring or analyzing the reflected portion of the surface waves to determine if a defect or discontinuity exists in the solid body and the depth or severity of the defect or discontinuity.

Abstract: Ultrasonic process and apparatus for monitoring and measuring the evolution with time of physico-chemical and biological phenomena. There is plunged into the medium or media (4) to be monitored a bar (3) into which ultrasound (2) is injected in order to collect secondary echoes (F2, F3) due to numerous reflections from the lateral surface of the bar (3) brought into contact with the medium (4), one of the secondary echoes (F2) is selected and the evolution with time of the amplitude of this echo is recorded, this representing the evolution of the medium being monitored, in particular the setting of concrete or the polymerization of a resin.

Abstract: Method for the ultrasonic testing of ferritic bodies having a cladding surface, a surface opposite the cladding surface, a cladding disposed on the cladding surface, an ultrasound transmitter radiating from the surface opposite the cladding surface into the body at an angle relative to the cladding surface, and a receiver for receiving reflections emanating from a fault in the body, which includes radiating longitudinal waves from the transmitter into the body at an angle between 70.degree. and 86.degree. relative to the perpendicular.

Abstract: A method and apparatus of detecting fractures along the wall of a formation, such as a well formed by test-drilling, provides for the transmission of ultrasonic signals in a direction essentially perpendicular to the wall from a position spaced from the wall by a predetermined distance and the reception of the ultrasonic signals which may be reflected by the wall. The space of predetermined thickness between the transducer which generates the ultrasonic signals and the wall is filled with an intermediate material which does not form a distinct interface with the wall of the type which would be able to produce an appreciable parasitic reflection of the transmitted signals.

Abstract: A method for the scanning of non-linearly dispersive objects whereby changes of the energy spectrum of echographic signals can be quantitatively related to parameters of the objects examined, that is to say the ultrasonic attenuation factor .beta. and the exponent r which characterizes the relationship between the non-linear variation of the attenuation and the frequency. To this end, the signals received are split into a number of (n) substantially equally wide, consecutive frequency bands which together cover approximately all frequencies of the signals received. The envelope of the signals in each frequency band is determined and each of the envelopes is multiplied by a correction signal in order to compensate for the diffraction effect. The logarithm of the envelopes thus corrected is determined, after which the following operations are performed by means of the n signals thus obtained:(a) the slope .beta.f.sub.i.sup.r of each of these n signals is determined;(b) this signal .beta.f.sub.i.sup.

Abstract: To monitor the deterioration of a weld (10) between a tube (11) and tube plate (12) which has been repaired by a repair sleeve (14) inside the tube and brazed at one end to the tube, ultrasound from a crystal (21) at the end of a rod (24) is launched into the tube through the braze (15) and allowed to travel along the tube to the weld and be reflected back along the tube. The technique may also be used for the type of heat exchanger in which, during construction, the tubes are welded to the tube plate via external sleeves in which case the ultrasound is used in a similar manner to inspect the sleeve/tube plate weld.

Abstract: A special angle beam probe for ultrasonic testing includes at least one ultrasonic vibrator fastened in a beam probe housing on a wedge-shaped support body which may be formed of Plexiglass, using damping means. The ultrasonic beam of the vibrator strikes the surface of the test piece at an incidence angle other than 0.degree., as measured from a perpendicular at the surface of the test piece at the point where the beam strikes. The ultrasonic beam furthermore strikes the test piece surface at an oblique angle between 0.degree. and 360.degree. subtended between a principal beam probe axis and the beam, as seen in the direction perpendicular to the beam probe from above. The novelty of the invention is that the special angle beam probe includes a multiplicity of prefabricated beam probe subassemblies. The ultrasonic vibrator of each subassembly is fastened with a predetermined incidence angle within a first beam probe housing.

Abstract: The disclosure is directed to a method and apparatus for non-destructive inspection of a solid workpiece, such as a steel workpiece. In accordance with the method of the invention, ultrasound is generated at an annular ring or portion thereof and focused into a hollow substantially cone-shaped beam, or sector thereof. The beam is directed at the surface of the workpiece so as to establish shear mode ultrasound energy in the workpiece. Ultrasound energy is then received from the workpiece (e.g. by reflection or transmission) and characteristics of the internal structure of the workpiece can be determined from the received ultrasound energy. In the preferred embodiment of the invention, the beam is configured such that the ultrasound energy impinging on the surface of the workpiece is at a sufficiently large angle with respect to the normal to the surface such that primarily shear mode of ultrasonic energy will be established within the workpiece.

Abstract: An ultrasonic echo sounding device permits observation of the web formation and/or the pulp suspension flow on the wire part and in the head box of a paper machine. The device includes a series of ultrasonic detectors connected to the wall of the flow channel in the head box and/or to the forming wire. The detectors direct an ultrasonic field at the pulp suspension layer, and the echo signals received from the pulp suspension layer are detected. The detectors operate as acoustic lenses so that the focal points thereof are located in the transverse direction of the pulp suspension flow and in the direction of thickness of the pulp suspension layer in a manner whereby information concerning fibre bundles, air bubbles, variations in consistency, corresponding parameters and their variations in the transverse direction of the pulp suspension flow and in the direction of thickness of the pulp suspension layer are indicated by the device.

Abstract: The properties of the surface layer of a material are measured by a technique which employs the transmission of ultrasonic waves from varying angles of incidence into a specimen, from a transducer at a point spaced from the specimen. The backscattered waves are detected and evaluated from the varying angles to detect the local maximum intensity, from which the corresponding properties of the material are determined.

Abstract: A focusing ultrasonic transducer element comprising an ultrasonic propagating medium and an ultrasonic transmitting and receiving transducer. The ultrasonic propagating medium is provided with a convex spherical or cylindrical portion in one end and a concave spherical or cylindrical portion in the other end.

Abstract: An apparatus for emitting and receiving sound signals includes a cylinder into which a sound transducer is mounted. The transducer is mounted to transmit a sound beam normal to the axis of the cylinder. The cylinder is connected to a position detection circuit for determining the angular position of the cylinder about its axis. A system for processing data produced by such a sound transducer apparatus includes circuitry for determining the true position of the cylinder from the position circuit, for alternately causing the transducer to emit and receive sound energy, and for sampling the energy signal received by the transducer when the position detection circuit indicates that the cylinder is at one of several preselected angles. The sampled information is recorded on paper or magnetic media.

Abstract: An acoustic microscope comprising an acoustic transducer which performs both generation and detection of acoustic wave beams, and a sample holding member which opposes to an acoustic wave transmitting and receiving surface of the transducer, to hold an object sample through an acoustic wave propagating medium and to offer behind the sample a layer of an acoustic impedance unequal to that of the sample, so that the sample holding member is moved in parallel, thereby to detect acoustic waves reflected from front and rear surfaces of the sample and acoustic waves reflected from a surface of the sample holding member without reaching the sample and to measure amplitudes and returning periods of time of the reflected acoustic waves, so as to measure the velocity of sound through the sample of unknown thickness, the acoustic impedance of the sample, etc. from the measured values.

Abstract: Acoustical images are generated by frequency demodulating an electrical signal having frequency deviations corresponding to the scattering properties of a media supporting acoustic pulse propagation against which the signal is projected. The system includes a transmitter which generates a signal at a defined frequency, which signal is then transformed into an acoustic pressure signal and projected against the media by a transducer. The transducer also receives acoustic pressure signals reflected from the media. A receiver coupled to the transducer transforms the reflected acoustic pressure signals into electrical signals which are then frequency demodulated. The demodulated signal contains instantaneous frequency deviations responsive to the scattering properties of the media. The frequency demodulated signal may be processed by circuitry to generate a video signal, which is then algorithmically processed by a scan converter and displayed on a video screen.

Abstract: An engine timing apparatus comprises an ultrasonic transducer 8 which directs a pulsed ultrasonic beam into a cylinder and converts the reflected ultrasonic signals into electrical signals. A sample/hold circuit 67 samples this signal at a time after each pulse when signal reflected by a piston ring passing through the beam are expected. A microcomputer 65 detects changes in the level of the sampled signal caused by the piston rings as the crankshaft rotates, and receives signals from a transducer 71 indicating the crankshaft position to allow top dead center position to be found. The microcomputer receives signals from a microphone 51 directed at a fuel injector indicative of the onset of ignition and calculates the timing angle of the engine. The apparatus also calculates engine speed and detects piston slap.

Abstract: An ultrasonic probe for puncture treatments is constructed in a manner that a guide member, for guiding a puncture needle, is provided on a side surface of an ultrasonic probe of a linear scanning type, with a needle being positioned by the guide member to be movable at right angles to the surface of the body of a patient, and a beam of ultrasonic wave is emitted by the probe in a direction oblique to the length dimension of the needle. The probe may be positioned obliquely to the needle, in which case, an acoustic coupling member of a wedge shape is inserted in the gap formed between the emitting end of the probe and the body. Alternatively, the probe may be positioned parallel with the needle in which case a wedge shaped member capable of deflecting the ultrasonic waves, is placed on the emitting end of the probe, and a wedge shaped acoustic coupling member is connected to the deflecting member so as to deflect the ultrasonic waves to be oblique to the needle within the body.

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: In ultrasonic flaw inspection for determining the size of a flaw by emitting an ultrasonic wave to a subject via a probe and receiving an ultrasonic echo from said flaw existing inside said subject, changes in the propagation distances of the ultrasonic echoes before and after movement of said probe through a micro-small distance are compared with each other and the ultrasonic echoes are determined to result from the same flaw if the change width falls within a predetermined value determined by the angle of incidence of the ultrasonic wave and the directional angle.

Abstract: The amplitudes of electrical signals generated by a transducer in an ultrasound scanning system are controlled by applying the electrical signals to an electrical filter whose frequency pass characteristics can be varied. As the ampltude and frequency of the generated electrical signals decrease due to passage through tissue, the low frequency of the filter is reduced. The control of the filter can be automatically implemented or can be manually implemented by the system operator.

Abstract: A transducer located in a reservoir that contains ultrasound-transmitting liquid directs and receives beams of ultrasound onto and from a rotating reflector which is also located in the reservoir. A diaphragm transmits the ultrasound from the liquid to a body which is to be analyzed. The results of the ultrasonic analysis are displayed on a cathode ray tube which is synchronized with the transducer and the rotating reflector.

Abstract: A scanner for periodically scanning an object to be examined with a beam of ultrasonic radiation. A transducer mounted within a housing emits a beam of ultrasonic radiation. The beam is guided and deflected respectively to a continuously rotating scanning reflector which is disposed opposite a stationary object reflector, from which the beam is directed to the object. The beam propagation path further includes a first focussing member adapted to focus the beam to a focal point within the housing, and a second focussing member adapted to focus the beam to a focal point within the object. In a preferred embodiment the first focussing member can be selectively adjusted. Thereby the focal area of the beam in the object can be conveniently shifted.

Abstract: A method of ultrasonically inspecting the internal structure of a multi-ply composite material using ultrasonic transducers includes the steps of positioning an ultrasonic transmitter in acoustical contact with one surface of the material, directing a beam of acoustic energy into the material with the angle of incidence of the beam with respect to the surface being less than the second critical angle for the material but greater than normal to the surface, and receiving the reflected energy. In one embodiment, the transmitting and receiving transducers are positioned with their axis perpendicular to the orientation of the reinforcing fibers within the ply being inspected. In another embodiment, the transmitter and receiver are aligned at equal angles on either side of a line which is perpendicular to the orientation of the fibers. The receiver may be located on the same or the opposite side of the material from the transmitter.

Abstract: A probe for obtaining information about a fluid comprising an electrically-shielded transducer having a lens for focusing energy waves, the transducer being attached to a cable and mounted in a protective sheath supported by a rod, whereby the transducer can be immersed in the fluid and moved around therein to take readings at various locations.

Abstract: A method of testing the integrity of the internal lining of a hollow body, especially a pipeline, by transmitting an ultrasonic wave from the exterior of the body through the adjacent wall of the body and monitoring the wave, if any, reflected from the opposite wall. In many cases, especially concrete linings, an intact or partially intact lining on the adjacent wall will absorb the ultrasonic wave and there is no reflected wave. A reflected wave frequently indicates loss of the lining on the adjacent wall although in some cases depending on, for example, the thickness of the lining or the material of which it is made, a reflected wave may be obtained even when the lining is intact. In such cases comparison of the reflected wave with predetermined standards provides an indication of whether or not the lining is intact.

Abstract: Ultrasonic flaw-detection method for austenitic alloy steel longitudinally welded pipe or tubing adopts shear wave angle method using a broad-band high-damping and non-resonance type transducer.

Abstract: An ultrasonic test probe comprises a transducer and an electrical circuit, particularly means for generating the high voltage transmit pulse to the transducer, all disposed within the probe housing. The high voltage transmit pulse is produced by current flow through an electrical inductor. Other circuit components are also arranged within the probe housing.

Abstract: Dark field viewing apparatus comprises either (a) a source of coherent plane wave radiation and focused coherent receiving means, or (b) a source of focused coherent radiation and a coherent receiver of plane wave radiation, the source and receiver being axially aligned in both cases; and elimination means to eliminate any radiation which in the region of the focus would travel substantially parallel to the axis of the apparatus. The apparatus may be a transmission or a reflection scanning acoustic microscope or a holographic recording system, and the elimination means may be a small acoustically-absorbent stop.