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: An apparatus for measuring the interior dimensions of the walls of a hollow body. The apparatus is insertable into a restricted opening of the hollow body and includes means for transmitting a beam of electromagnetic energy toward an interior wall of the hollow body. When the electromagnetic energy illuminates the interior wall, acoustic waves are radiated back to the apparatus. The apparatus detects the acoustic waves and measures the elapsed time between transmission of the electromagnetic energy and detection of the acoustic waves. From elapsed time measurements the dimensions of the interior walls are obtained.

Abstract: A device for forming acoustical images comprises an ultrasonic source, a linear array of first receiving transducers for receiving the echoes from a target illuminated by a source. The signals from the linear array of first receiving transducers are processed by a system comprising an oscillator at a frequency higher than that of the source, and, for each said receiving transducers, a mixer, a filter for separating the components of the beating frequency and a transmitting transducer.

Abstract: An ultrasonic scanner for producing a sector scan in an object to be examined in which one or more ultrasonic transducers traverse an arcuate path with respect to a reflector which is positioned to receive the ultrasonic waves scanning the surface of the reflector from each of the transducers and converge such waves at a point of a preselected distance in front of the reflector. In general, the ultrasonic waves are converged at a point outside the scanner and inside the object to produce a sector scan in the object having its center at the convergence point. In one embodiment of the scanner the reflector only partially reflects the ultrasonic waves and an additional stationary transducer is provided which is positioned to produce ultrasonic waves which radiate through the reflector and coincide with one of the lines of the sector scan, thus permitting simultaneous M-mode or pulse Doppler echo information to be obtained in perfect registration with the sector scan lines.

Abstract: An array of transducers is provided for transmitting pulses of ultrasonic pressure waves into a body and translating reflections received into corresponding pulses of electrical waves. Phase changing means, which may preferably include heterodyning means, are connected between each transducer and selected taps on one delay line. The taps are just close enough together to provide reasonable overlap of the pulses of electrical waves at the summing point at one end of the delay line. Focussing is attained by adjusting the phases of the waves applied to each tap so that the cycles of carrier wave within the overlapped portion of the pulses at the summing point have reasonable phase coherence.

Abstract: An electrodynamic sound converter which comprises a magnet adapted to generate a magnetic field and direct same onto the surface of the workpiece to be checked by the electrodynamic sound converter, and which also includes an excitation coil located between the magnet and the workpiece to be checked for generating electromagnetic oscillations. That end of the magnet core of the magnet which faces the workpiece to be checked is so designed that the magnet core decreases in cross section toward its foremost point which is closest to the surface of the workpiece to be checked, the rate of increase increasing in the direction toward the foremost point of the magnet core.

Abstract: An ultrasonic transducing unit comprising a central section, which cooperates with only a small portion of the relatively large aperture of an acoustic lens, and an annular section, which cooperates with the remainder of the aperture, can be selectively operated by switch means to utilize the relatively large depth of focus detected signal of the central section alone or to utilize the relatively small depth of focus detected signal of both the central and annular sections together.

Abstract: In an ultrasonic investigating apparatus a transducer can receive reflections from points in the body for which the position in one direction is relatively well known as a result of accurate range gating but for which the position in another direction is relatively less known in view of the relatively wide ultrasound beams used. Thus the reflections are only known as originating from lines in the body. These line integrals of reflection of ultrasonic energy are processed by methods appropriate to line integrals in general, as known for line integrals of X-ray absorption for example, to more accurately position the reflecting points in the body. A propagation velocity distribution can also be determined for the body to further improve the accuracy.

Abstract: Non-destructive testing with ultrasonic energy is performed by scanning a focused ultrasound beam until a region of interest is detected and rescanning this region with the beam focused at a plurality of depths. Apparatus for ultrasonic body scanning for medical purposes may include an actively driven transducer crystal which may be dynamically focused. A beam of energy produced by the transducer will be coupled to the patient by a liquid path and a movable mirror may be interposed along the liquid path to cause scanning of the beam.

Abstract: Apparatus is described for monitoring phase currents and torsional vibrations of a turbine-generator which are indicative of the dynamic response of the machine during operation under load. The monitoring system disclosed includes probes which are operable to sense rotation of the main shaft of the turbine-generator and to feed the resulting signals to a vibration network. The vibration network eliminates from the signals any false components present at frequencies equal to multiples of the rate of rotation of the shaft and produces a composite vibration signal containing only true components of shaft torsional vibration. The composite vibration signal and a set of three phase current signals determined by stepping down, filtering, and amplifying the generator line currents are monitored continuously but recorded only when at least one of two signals derived from selected components of the composite vibration signal and phase current signals exceeds reference levels in an alarm system included in the monitor.

Abstract: A system and technique for determining the total radiated ultrasonic power output from a diagnostic ultrasound device having an output transducer includes a water chamber having a parabolic reflector. The transducer is mounted on the chamber at a location so that acoustic power from the transducer is focussed by the parabolic reflector to a first thermistor chip mounted in the chamber on a sound-absorbing rubber plate. The rise in temperature of the thermistor chip due to sound absorption changes its resistance. The thermistor chip is connected in one leg of a Wheatstone bridge. A reference thermistor chip is mounted on the rubber plate away from the ultrasonic beam and is connected in an opposite leg of the bridge. Starting from a null setting of the bridge, the output of the bridge after a suitable "response time" is in accordance with the acoustic energy delivered by the transducer.

Abstract: A receiver probe for ultrasonic energy is described in which the surface deformation caused by compressive wave energy affects a thin gas-filled gap, its width being in the order of 10.sup.-7 meter. The gap is formed by opposing surfaces of an optical prism and an optical interference means. A beam of light is conducted to the boundary surface between the prism and gas. Changes in reflected and/or transmitted light beam portions resulting from compressive wave energy induced changes in gap width are sensed by opto-electric means.

Abstract: Manipulator assembly for testing the material of a pipe elbow from the inside thereof, the pipe elbow being secured to a pipe union extending from a pressure vessel openable for receiving therein a vertically extending manipulator mast having an arm carrying a manipulator, the manipulator being movable by the arm in vertical direction, rotatably about the axis of the mast and in direction of the longitudinal axis of the arm and transversely thereto, the manipulator includes a multimember vehicle drivable in direction of the pipe-union and pipe-elbow axis, the members of the vehicle being articulatingly connected to one another and having extensible and retractable support legs for supporting the respective vehicular members centered relative to the inner periphery of the pipe elbow, the support legs having roller members at the end thereof for transporting the vehicular members in axial direction of the pipe union and the pipe elbow, the vehicular member located at the head of the multimember vehicle being a

Abstract: Ultrasonic waves present on the surface of a workpiece are received contact-free by an optical sensing arrangement which includes a frequency stabilized single mode laser which illuminates the vibrating surface portion. Reflected light from the illuminated portion, which light is frequency modulated by the Doppler effect of the ultrasonic wave, is collected by a lens and applied to a narrow band absorption light filter. The frequency of the laser and the filter are selected to cause the center frequency of the light to fall at a point along the steepest slope of the filter absorption curve. The change in light frequency causes a corresponding change in light intensity passing through the light filter and the filtered light, now amplitude modulated, is provided to photoelectric means. A feedback circuit maintains the frequency of the laser constant.

Abstract: A magnet is used to create a static magnetic field adjacent to the surface of a conductive material. At least one conductor runs through the magnetic field. When a pulse of current flows through the conductor, an elastic wave is generated in the material. In a preferred embodiment, a row of individual permanent magnets is used to create a periodic magnetic field. One side of a coil is placed in the periodic magnetic field so that a sheet of current moves transverse to the magnetic field when a pulse of current flows through the coil. When the coil is oriented parallel to the row of magnets, a horizontal shear wave is generated in the material. When the coil is oriented transverse to the row of magnets, a Lamb wave is generated in the material.

Abstract: Spheroidal cast iron pieces are tested by clamping each individual piece on a vibratory test rig together with a reference datum piece and using the measured amplitude and frequency of the system at resonance to derive an automatic indication, through an electronic logic circuit, of the quality of the piece under test compared with the reference piece.

Abstract: An apparatus for measuring flow rate of powders or granules forced out off the periphery of a loading table to fall down gravitationally. Deflector members arranged within the gravitational fall path of the powders or granules are subjected to a rotary force by impingement thereon of the powders or granules. Flow rate is measured as proportional to the moment for rotation.

Abstract: An ultrasonic imaging system for medical and industrial applications produces quantitative acoustic impedance distributions from reflection data. The method and scanner apparatus with analog computation circuitry herein described acquires echo pulses reflected from impedance discontinuities in the specimen and computes impedance projections. The ensemble of projections, as in other computerized tomography systems, is used for reconstruction of the images which in this case are impedance distributions in a thin slice of the specimen.

Abstract: Disclosure is made of a method for checking the thickness of sheet materials, whereby acoustic oscillation is sent in the form of a traveling wave through a material being checked roughly perpendicularly to its surface. The amplitude of the acoustic oscillations that have passed through the material being checked is measured and compared to that of a reference signal, whereby the thickness of the sheet material is determined. The proposed device for checking the thickness of sheet materials comprises an acoustical radiator and an acoustical receiver. The working surface of the radiator and receiver are roughly parallel to the surface of a material being checked, which material is placed between the radiator and receiver. The distance between the radiator and receiver is selected to be in excess of the spatial extension of the traveling wave during each measurement period.

Abstract: A maintenance alarm actuator for a fluid filter actuates an alarm when contaminant has accumulated in the filter. The actuator is connected to fluid lines upstream and downstream of the filter. Included in the actuator are a valve and a biasing mechanism which biases the valve. The valve responds to the difference in the line pressures, and the actuator is initially triggered when the pressure of the upstream line exceeds that of the downstream line by an amount sufficient to overcome the force of the biasing mechanism. When initially triggered, the actuator vents the downstream line to the alarm, thereby increasing the difference in line pressure and causing itself to trigger completely.