Abstract: An ultrasonic real-time inspection method which is user-friendly in an interactive environment to provide ease of operation, as well as a combination of consistency, thoroughness, and speed of operation in flaw detection not achievable by other methods. The method offers significantly increased pattern recognition capability, which provides greater automation potential and reduced missed detection and false alarm rates.

Abstract: A cart for inspecting a drill pipe having a platform with an ultrasonic inspection unit thereon, a first pair of wheels connected to the platform so as to move the platform longitudinally along the drill pipe relative to a rotation of the drill pipe, and a bearing connected to the platform at a location distal of the first pair of wheels. The bearing serves to support the platform above an adjacent drill pipe and allows the platform to move longitudinally along the adjacent drill pipe in correspondence with the movement of the first pair of wheels. The first pair of wheels are canted at an angle relative to the longitudinal axis of the drill pipe. A sensor wheel extends outwardly of the platform and rotates during the movement of the platform along the drill pipe. The platform has at least one handle extending upwardly from the platform. The bearing includes a pair of rollers that have an axis of rotation which is transverse to the longitudinal axis of the adjacent drill pipe.

Abstract: Apparatus is disclosed for providing one hundred percent inspection of natural gas mains under operating flow conditions. The apparatus includes a scan unit assembly which is inserted into the gas main to collect data for the production of graphic images of the wall of the gas main. The scan unit includes a plurality of scan rollers, each containing an ultrasonic transducer, which traverse the surface of the wall defining the inner diameter of the gas main. The ultrasonic transducers transmit interrogating pulses into the wall of the gas main at a pre-determined spaced apart interval resulting in a helical scan pattern of interrogating pulses. The return pulses from the surfaces defining the inner diameter and outer diameter of the gas main and any imperfections and/or flaws within the wall of the main are received by the transducer and transmitted to a display unit for a visual indication (a tomograph) of the wall of the gas main.

Abstract: An apparatus for detecting flaws using supersonic waves measures a thickness of a test object or a position of a cavity inside the test object by employing pair of ultrasonic probes. By changing a relative position of one ultrasonic probe to that of the other ultrasonic probe, a plurality of waveform data of ultrasonic reception signals is acquired. Each acquired waveform data is added per corresponding unit of time. Since a surface wave component of each waveform data has a shifted phase due to the difference in arrival time, a level of the surface wave component is offset and thus minimized through addition of the waveform data.

Abstract: An apparatus for detecting defects comprises a pair of ultrasonic probes which are gimballed onto a pair of elongate members. A pair of yokes are gimballed onto the elongate members. Springs cause an interaction between the yokes and the ultrasonic probes such that the ultrasonic beams travel in a plane parallel to the longitudinal direction of the elongate members. The elongate members are slidably mounted on a carriage and the elongate members are arranged apart at a predetermined angle. The carriage is mounted to travel on an arcuate member to scan the corner of joint between a pressure vessel and a nozzle in a direction radially with respect to the axis of the nozzle. The arcuate member is rotatably mounted to a support member to scan the corner or the joint circumferentially with respect to the axis of the nozzle.

Abstract: A scanner head for ultrasonic imaging of structures generates a display through an ultrasonic transceiver. The scanner head includes a transducer adapted to engage the surface of the structure. Rollers are positioned fore and aft the transducer, and one roller drives a position increment signal generator which drives the transceiver and display circuitry. A couplant delivery system includes nozzles bracketing the transducer in the direction of movement of the scanner head. The flow is controlled by a single valve on top of the head. In this manner, couplant in the desired amount is delivered correctly and concurrently as scanning proceeds.

Abstract: A system for relatively accurately measuring the velocity and time of flight of ultrasonic signals in the thickness direction through moving web-like materials, such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of the moving web-like material. The ultrasonic transducers are disposed in fluid-filled wheels to provide acoustical coupling between the transducers and the web-like material. In order to eliminate errors, known as trigger jitter, inherent in systems used to digitize ultrasonic signals for manipulation by a digital computer, a pulse echo box is provided to enable the capture of a reflected ultrasonic signal in addition to the ultrasonic signal transmitted through the web. By cross-correlating the transmitted and reflected ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated.

Abstract: Columns, walls and other solid structures of concrete, wood, masonry or other materials are non-destructively tested by acoustic signals transmitted from a carriage. The carriage has a frame which is wheel mounted to move over the surface of the test candidate. An internally-mounted piezoelectric crystal roller as an acoustic signal generator or receiver is suspended from the carriage with two degrees of spring freedom to allow accommodation of irregularities in the test candidate surface. The assembly including the piezoelectric crystal roller and its flexible mounting are configured as a replaceable module relative to the carriage frame. The same carriage is useable as an echo type acoustic scanner or, in combination with other devices or carriages, as either an acoustic transmitter or receiver although inclusion of elements to perform both functions within the same carriage is contemplated.

Abstract: A system and method for dynamically and non-destructively measuring the longitudinal stresses in a rail of a continuous rail track includes an ultrasonic transmitter which transmits a signature coded pulse pattern through a rail which pulse pattern is altered by the rail section dependent upon the longitudinal stress within the rail. The altered pulse pattern is then received and a data processor, in conjunction with a rail height detector, a rail temperature detector, and a rail splice detector, dynamically determines the longitudinal stresses in the rail as a function of the received pulse characteristics and calculates the stress free temperature (SFT) of the rail. A rail marker marks portions of the rail having unacceptable SFT values. Stress and related rail data are recorded on a data log. A position sensor provides milepost positions to three decimal places.

Abstract: A system and method for dynamically and non-destructively measuring the longitudinal stresses in a rail of a continuous rail track includes an ultrasonic transmitter which transmits coded focused shear pulses through a rail which are subsequently received by a linear array of sensors. A displacer adjusts the separation between the transmitter and the sensors to maximize the signal intensity received by a centrally located one of the sensors. A data processor, in conjunction with a rail height detector, a rail temperature detector, and a rail splice detector, dynamically determines the longitudinal stresses in the rail as a function of the velocity of propagation of the pulses, the stress free temperature (SFT) of the rail, and activates a rail marker to mark portions of the rail having unacceptable longitudinal stresses. Stress and related data is recorded on a data log. A video camera provides observed rail separation data to the data processor.

Abstract: An ultrasonic rail web centerline detector locates the web centerline (18) of a longitudinal rail (12) having a head (80), a base (82), and a web therebetween. The detector includes an ultrasound sensor (14) acoustically coupled to the head (80) of the rail (12) for transmitting ultrasound energy through the rail (12) and for generating electrical signals corresponding to received reflected ultrasound energy. A controller (16) responsive to the electrical signals generates control signals representative of a lateral and angular displacement of the ultrasound sensor (14) with respect to the web centerline (18) of the rail. The position of the ultrasound sensor is adjusted as a function of the control signals representative of the lateral and angular displacement. The ultrasound sensor includes a center transceiver (30) and side transceivers (32, 34) which are acoustically coupled to the head (80) of the rail (12).

Abstract: A method and system for nondestructively testing in a continuous sequence a multiplicity of railroad track crossties of wood or concrete to determine the condition and life expectancy of each of the crossties and of the track as a whole. The system includes an electric pulse generator and a pair of transmitting and receiving transducers, which transducers are adapted to be brought into moving contact with the crossties at respective locations straddling desired test regions thereof, for example, the regions under a tie plate, for sending sonic mechanical pulses through that region of the crosstie from one transducer to the other. If desired, three pairs of transducers may be provided for simultaneously straddling both tie plates and a medial reference zone on each crosstie. The transducers and the pulse generator are carried by a vehicle riding on the track rails, along with a computer for processing/evaluating/storing/reproducing the test data.

Abstract: An apparatus is disclosed for nondestructive evaluation of defects in hot terials, such as metals and ceramics, by sonic signals, which includes a zirconia buffer in contact with a hot material being tested, a liquid couplant of borax in contact with the zirconia buffer and the hot material to be tested, a transmitter mounted on the zirconia buffer sending sonic signals through the buffer and couplant into the hot material, and a receiver mounted on the zirconia buffer receiving sonic signals reflected from within the hot material through the couplant and the buffer.

Abstract: The invention is a method for the on-line nondestructive determination of the internal bond strength of composite panel products. The method involves impinging an ultrasound pulse against the panel by a first transducer and receiving a transmitted pulse at a second transducer. The received signal strength, temperature and panel thickness are entered into an algorithm from which the internal bond may be calculated. Preferably the receiving transducer is located on the opposite side of the panel and displaced somewhat from the first transducer. The inclusion of temperature and panel thickness as independent variables greatly improves the accuracy over that available from uncorrected ultrasound testing.

Abstract: This invention relates generally to an ultrasonic wheel probe for rolling along a workpiece to be tested for flaws, having a plurality of ultrasonic acoustic transducers and an acoustic barrier that rest in a coupling fluid. The instant invention comprises an improved means for detecting the distance between the transducer array and the surface of the workpiece.

Abstract: An on-line instrument in rolling contact with a papermachine web determines the web's strength and elastic modulus properties by intermittently pulsed sonic waves transmitted through the traveling web mass between a full circle, piezoelectric transducer emitter and identical receiving transducers respectively displaced from the emitter along the MD and CD web axes. Transducer signals from the receivers are analyzed by cross-correlation function techniques relative to the original stimulation reference signal to isolate the desired data signal from integral noise.

Abstract: An ultrasonic inspection device having an array of opposing transducers that longitudinally, transversely, and obliquely transmit sonic beams through tubular members having a range of diameters such that refracted beams meet on the inner surface of the members. Alternate halves of the array of transducers transmit and receive sonic beams reflected from defects in the tubular members using both the pulse-echo and pitch-catch methods.

Abstract: A system is provided for measuring the velocity of vibrations in a moving web, such as a sheet of paper. The system includes a transmitter coupled to the paper to transmit waves and a receiver to receive the waves. A signal processing system is used to determine the velocity.

Abstract: An ultrasonic testing device of the type comprising a fixed hub with at least one ultrasonic transducer as well as an annular rolling means mounted for rotation on said hub and surrounding said transducer, this latter being mounted on the hub through a support whose external face opposite said transducer defines with the inner face of said rolling means a rotational sliding slit, the coupling between said support and said rolling means being provided by an ultrasonic liquid present in said slit, wherein a spongy resilient element is provided imbibed with said coupling liquid, said element being housed in a recess in said hub and being applied resiliently against the inner face of said rolling means.

Abstract: An ultrasonic wheel probe of the type having a wheel-shaped container with an annular outer surface for rotating about an axis of rotation and rolling upon a specimen to be tested is provided with a plurality of transducers for transmitting and receiving ultrasonic acoustic energy, respectively. In accordance with the invention, an acoustic barrier is interposed between the transmitting and receiving transducers, and immersed in the coupling fluid, so as to isolate the transmitting and receiving transducers from one another. With this arrangement, echoes emanating from the interface, or surface, of the specimen being tested are prevented from reaching the receiving transducer. By eliminating the interface echo the only echoes received are from the back wall of the specimen under test or from anomalies within the specimen, thereby permitting testing from the front surface to the back wall of the specimen.

Abstract: An ultrasonic probe for inspecting a weld between a cylinder (C) and a pipe (P) is caused to move in a holder at the end of an arm (11) pivoted at a point on the axis (Z) of the pipe so that the line (12) of transmission from probe penetrates the weld and, when projected beyond the weld, intersects the axis (Z) of the pipe (P) for all positions of the arm.

Abstract: A mounting for locating in side-by-side relationship two ultrasonic wheel probes 10 used for ultrasonically inspecting a pipeline, the mounting including a mounting member 12 defining a slide 16, and two slider members 14 located in back-to-back relationship in the slide 16 and retained therein by a backing member 38. Each slider member 14 is adapted to locate one of the wheel probes 10.

Abstract: Apparatus for ultrasonic detection of flaws in the rail base of a track rail includes a sliding shoe having a transducer unit and coupling medium reservoir mounted thereon. The transducer, which is part of an ultrasonic testing system, transmits search signals into the rail base and receives associated reflected signals thereof. These signals, being capable of pictorially representing defects in the base of the rail, are monitored by the tester. The preferred embodiments allow for relative movement of the transducer unit and coupling medium reservoir along the base of the rail in order to provide for a succession of transmitted and reflected signals along the longitudinal extent of the rail base so as to test for flaws, defects, etc. in the same.

Abstract: A fully wetted ultrasound scanhead for medical applications is described in which the motor and the rotor are enclosed within a sealed housing filled with ultrasound coupling fluid. The invention includes a drive belt to drive the rotor from the motor, rather than a precision drive means. Speed adjustment means, including an encoder disk mounted on the rotor, provide feedback for an electronic speed controller. Accordingly, the speed of the motor can be adjusted as a direct consequence of the actual speed of the rotor.

Abstract: A wheel probe for ultrasonically inspecting a component, such as the wall of a pipeline, is of hollow form to define a chamber in which an ultrasonic transducer is located. The transducer is supported by a mounting which occupies a major proportion of the chamber and comprises material for attenuating background noise in the wheel probe. The chamber is closed by an end member which also comprises material for attenuating background noise, while an elastomeric tire on the rim of the wheel probe extends over a portion of reduced diameter of the rim to attenuate unwanted ultrasound.

Abstract: A roller-type ultrasonic probe comprises a support having two parallel limbs, and two coaxially aligned hubs each extending from a respective limb towards the other. An ultrasonic transmitter is mounted in one hub, a receiver is mounted in the other, and an acoustic screen is disposed between the adjacent ends of the hubs. Respective glycerine-filled rollers are mounted on each hub, and a common (or split) tire fits over both rollers. The respective axes of the transmitter and the receiver are preferably inclined at about 5.degree. and 7.degree. respectively towards the radially extending plane between the transmitter and receiver. The arrangement is particularly compact, and facilitates high-resolution ultrasonic investigation of bond quality in glass or carbon-fibre reinforced plastic sheets and other laminates.

Abstract: A roller-type ultrasonic inspection device for inspecting vehicle tires comprises a roller assembly 20 mounted on a non-rotatable hug 16. Two piezoelectric crystals 80,82 are mounted in the hub 16 such that their principal transmitting/receiving axes A and B converge generally radially outwardly of the hub. The angle between the axes A and B is selected such that when the roller assembly 20 is urged into rolling contact with the tread-bearing surface of a tire 90, the axes meet (allowing for refraction effects) in the body of the tire beneath the tread. This ensures that the device can detect defects in the body of the tire, and is relatively insensitive to the tread.

Abstract: A probe is provided which comprises a plurality of ultrasonic transducer elements, and is so arranged as to be capable of simultaneously transmitting and receiving ultrasonic beams of plural frequencies. Means is provided for changing the shapes of the effective acoustic field of the ultrasonic beams of each a predetermined number of frequencies by selectively operating the ultrasonic transducer elements or interchanging transducers. The shapes of the effective acoustic fields of the ultrasonic beams of the plural frequencies are made substantially coincident in accordance with the range of distance from the probe. Thereby, the measuring of the tissue or the like with coincident shaped beams of plural frequencies can be realized.

Abstract: A rotary ultrasonic scan head includes a housing 10 consisting of generally symmetrical housing portions 10A and 10B having respective mating surfaces 14 and 16 that abut when the housing portions are assembled. A cavity is defined within the housing by recesses 18, 27, 34 and 38 in housing portion 10A and by complementary recesses 20, 28, 36 and 40 in housing portion 10B, by boot 50 disposed on the housing portions in assembly, and by pressure-compensating diaphragm member 42 disposed within the housing portions in assembly. A rotor 12 including a plurality of ultrasonic transducers 22, an impeller 24, and an optically encoded member 26 is supported for rotation within this cavity. An acoustic coupling and driving fluid is supplied to and withdrawn from the cavity through fluid inlet bore 68 and fluid outlet bore 70 in housing portion 10A, with the fluid entering the cavity being directed at impeller 24.

Abstract: An ultrasonic sector scanner which utilizes rotating transducers uses an optical encoder for generating indexing signals. A slip-ring and brush assembly interconnects the transducers and electronic circuitry within the scanner.

Abstract: Ultrasonic equipment for examinations using section images comprises a scanning mechanism, which includes a wheel that can be driven to rotate and carries a plurality of focussing sound transducer heads having working ranges which cover only respective fractional parts of the depth of the section surface. Each sound transducer head is activated as the sound beam emitted by the sound transducer head moves in the section surface. The echoes received by the sound transducer heads are used to generate a section image. In order to improve the image quality, sound transducer heads having working ranges in different depths of the section surface are activated in succession. Pre-entry paths are associated with sound transducer heads for examining regions near the surface of the object to be examined. Selecting means are provided which ensure that only echo signals derived from echoes which have originated in the working range of an activated sound transducer head are used to generate the image.

Abstract: The present invention provides an ultrasonic scanning transducer for use in an ultrasonic scanning system that examines an object by directing a series of ultrasonic waves into the object, receiving electrical signals related to the echoes generated by the ultrasonic waves when they strike acoustical interfaces within the object, and displaying the information borne by the electrical signals relating to the nature and location of acoustical interfaces within the object. The ultrasonic scanning transducer includes transducer elements secured to a permanent magnet mounted for rotational movement within the housing of the transducer and a stator assembly for rotating the transducers and magnet continuously in a single direction. The stator assembly receives a periodic signal having a zero average value and creates therefrom a unidirectionally rotating magnetic field which exerts a force on and rotates the permanent magnet.

Abstract: A wheel probe for ultrasonically inspecting a component, such as the wall of a pipe, is of hollow form to define a chamber in which at least one ultrasonic transducer is supported to direct and receive ultra-sound through the wheel probe. The chamber is filled with an acoustic coupling liquid, and at least one resilient diaphragm is provided in the wall of the chamber so as to deflect in response to a difference in pressure thereon and balance the pressure of the liquid with that of the environment about the wheel probe.

Abstract: A device which measures the velocity of ultrasonic waves in a moving web is provided. A pair of wheels is mounted for continuous surface contact with the paper and a transducer, which contacts the web on each revolution, is located in each wheel for relating electrical and mechanical signals. Timing means measures the time it takes a mechanical signal generated at the first wheel to reach the second wheel. Noise reducing and amplifying means are provided for effective operation.

Abstract: The sonde comprises a measuring wheel carried by an arm which holds it in contact with the borehole wall and rotates it around the sonde axis so that the measuring wheel follows a helical path on the borehole wall as the sonde is raised in the borehole.

Abstract: A pipe inspection apparatus includes a vehicle which is capable of moving along the bore of the pipe, two rubber cup-shaped members at each end of the vehicle for aligning the vehicle lengthwise in the pipe, a floating assembly of inspection devices such as ultrasonic transducers disposed circumferentially around the vehicle, and at least four link members pivotally attached to the assembly and to the vehicle to constrain the assembly to move in a direction normal to the length of the vehicle. The assembly may be resiliently suspended from the vehicle, and may also be provided with a centralizing device, such as a rubber cup-shaped member or rollers or skids, to centralize the assembly in the bore of the pipe.

Abstract: A pipe inspection device for ultrasonically inspecting the wall of a pipe includes a support arm which is pivotally attached at one end to an inspection vehicle and at its other end pivotally supports a spindle at the end of which two wheels are rotatably mounted. One or more ultrasonic transducers are disposed inside each wheel so that when the vehicle is moved along the pipe, the wheels come into contact with the pipe such that the transducers are aligned in predetermined positions relative to the pipe. The device may be arranged for insertion in the bore of the pipe, or for assembly around the outside of the pipe.

Abstract: An ultrasound sensing apparatus suitable for human body scanning, particularly regions which are difficult to scan with larger ultrasound heads. The ultrasound transducers are mounted for rotation in an off-axis configuration. With this configuration, transmission and reception of sound occurs without the sound being normal to the membrane contacting the body. This eliminates reverberation problems and permits viewing of shallow tissue with a relatively small apparatus.

Abstract: A system for non-destructively acquiring and processing information about a test piece includes an array of ultrasonic transducers each adapted to transmit ultrasonic energy into the test piece and to receive ultrasonic energy transmitted back thereto to produce a response signal capable of representing deviation from the expected condition of the test piece. The transducers are mounted on a carriage to be transported relative to the test piece and a transducer control sequentially pulses the transducers while so transported to ultrasonically inspect the test piece and produce a set of response signals representing the inspection. A plurality of transducer monitors, one for each transducer, sequentially monitor each of the response signals and an analogue-to-digital converter converts each monitored response signal to a single set of digital data.

Abstract: An ultrasonic inspection device for nondestructive inspection of cylindrical members includes a pair of resilient inspection wheels which house multiple ultrasonic transducers. The inspection wheels are mounted in a carriage so as to ride along the surface of a rotating cylindrical member being inspected. Relative longitudinal motion between the carriage and the cylindrical member allows the inspection wheels to transcribe helical paths over the surface of the member.

Abstract: A portable apparatus for nondestructive ultrasonic inspection of oil field tubular goods includes a deck which mounts spaced drive rollers for rotating the pipe being inspected. A substantially box-shaped carriage moves on tracks above the pipe to allow a pair of ultrasonic inspection wheels to traverse the pipe. The combination of pipe rotation and carriage movement causes the inspection wheels to trace helical paths on the surface of the pipe. In an alternative embodiment, the rotating pipe is drive longitudinally through stationary ultrasonic equipment. A programmed control system and a method of ultrasonic inspection also are disclosed.

Abstract: A method of determining foreign material such as metal and bone particles in food products, the method using ultrasonic sound frequencies from a plurality of transducers disposed in a rotatable cylinder having a liquid copulant. The cylinder having a surrounding flexible wall which is compressed on top of the surface of the food products. The sound frequencies are transmitted through the food products and received back by a receiver in the transducers for monitoring any variance in the frequency indicating foreign material in the food products.

Abstract: Disclosed is a wheel probe for use on a pipe inspection vehicle. The wheel probe comprises a annular perspex outer rim with a polyurethane tire mounted on a hub assembly which, with the hub, defines a fluid-tight chamber containing an acoustic coupling fluid. A number of ultrasonic transducers are located inside the chamber and are positioned close to the inside circumferential surface of the rim. The hub assembly is carried by a spring loaded carriage which is secured through which ultrasound will pass.The wheel probe includes a guide wheel on each side. The guide wheels are carried by the carriage but are moveable bodily relative to the center of the hub assembly, and when deflected, they operate on the assembly to move the wheel probe to ensure that the outer rim of the wheel is correctly aligned relative to the pipe.The wheel probe has a number of shields spaced around its periphery.

Abstract: A system and method for performing ultrasonic inspection of a length of test material with ultrasonic transducing means emitting a beam of ultrasonic energy from within sealed wheel means containing a coupling fluid therein and having a flexible cylindrical surface member transparent to the ultrasonic beam and arranged for rolling contact along the test material. The system and method are characterized by spaced leading and trailing wheel means arranged for rolling contact along the length of test material. Ultrasonic transducer means in each of the leading and trailing wheel means are oriented so that a beam of ultrasonic energy emitted from the transducer means in one wheel means will enter the test material, be reflected from the bottom surface thereof, and be directed to and received by the transducer mean in the other wheel means.

Abstract: A system and method for performing ultrasonic inspection of a length of test material with ultrasonic transducing means emitting a beam of ultrasonic energy from within sealed wheel means containing a coupling fluid therein and having a flexible cylindrical surface member transparent to the ultrasonic beam and arranged for rolling contact along the test material. The system and method are characterized by spaced leading and trailing wheel means arranged for rolling contact along the length of test material. Ultrasonic transducer means in each of the leading and trailing wheel means are oriented so that a beam of ultrasonic energy emitted from the transducer means in one wheel means will enter the test material, be reflected from the bottom surface thereof, and be directed to and received by the transducer means in the other wheel means.

Abstract: A method and an apparatus for detecting the internal cavities in a continuous casting bar in which two opposite surfaces of a casting bar delivered from a continuous casting machine are held between a pair of rollers each having a hollow portion and are pressurized at a predetermined pressure thereby, and an amount of transmission of an ultrasonic wave having a predetermined frequency passing through the casting bar is detected by means of an ultrasonic wave device for transmission and an ultrasonic wave device for reception which are provided respectively in the hollow portions of the rollers to allow the ultrasonic wave to pass through the casting bar running through the rollers, thereby to detect the internal cavities in the casting bar.

Abstract: An ultrasonic transducer probe having a sealed rotor housing, a plurality of transducers mounted on a rotor disposed in said housing. A rotor shaft mounts the rotor and extends through the housing. A drive assembly including commutating and position indicating means receives said housing and rotor shaft and serves to drive the rotor, commutate electrical energy to and from said transducers and indicate the angular position of said rotor. A handle including means for driving said drive assembly is attached to said drive assembly to position the rotor housing and drive assembly against the body the rotate said rotor to cause the transducers to scan a sector of the body.

Abstract: Moving section plane pictures of a specimen are produced by contacting a predetermined peripheral portion of an ultrasonic transducer head with the specimen in the section plane. The transducer head has a circular internal cavity in which a wheel is mounted eccentrically for rotation about an axis. A plurality of ultrasonic transducers are mounted peripherally on the wheel. The gap formed between a transducer and the internal surface of the transducer head is a minimum along the peripheral portion where contact to the specimen occurs. Each transducer is energized only when passing through the sector subtended by the peripheral portion in contact with the specimen and echoes received by the transducer are displayed on a screen whose base line is synchronized to the movement of the ultrasonic beam.

Abstract: A device is provided for reducing internal reflections from the tire of an ultrasonic search wheel probe or from within the material being examined. The device includes a liner with an anechoic chamber within which is an ultrasonic transducer. The liner is positioned within the wheel and includes an aperture through which the ultrasonic sound from the transducer is directed.