Abstract: Guided ultrasonic waves are used for the detection of defective tubes in a heat exchanger or steam generator by using a transducer which generates a guided wave at predetermined parameters of phase velocity and frequency to operate at a point on a dispersion curve which minimizes leakage of ultrasonic energy to fluid surrounding the tube. Various techniques of generating ultrasonic waves of various phase velocities such as a comb type filter allow phase velocity points on a dispersion curve to be freely selected.

Abstract: An apparatus for conducting ultrasonic waves to and from a body of a molten material. The apparatus includes a buffer rod for transmitting ultrasonic waves to the molten metal, a second buffer rod for receiving ultrasonic waves from the molten metal, piezoelectric elements associated with each buffer rod, and cooling mechanisms for protecting the piezoelectric elements by maintaining the buffer rods at a prescribed rate of thermal equilibrium with the molten metal. The cooling mechanisms are configured so as to facilitate regulation of the air flow about the apparatus.

Abstract: A testing head is provided which operates in accordance with the contact technique and has a flexibly constructed adaptor piece that is adapted to an intended contour of the conical bottom surface. A ring structure, which is disposed on the base surface of the adaptor piece, is constructed as a one-piece or multiple-piece ultrasonic transducer.

Abstract: A method for ultrasonic imaging of interior structures and flaws in a test specimen with a smooth or irregular contact surfaces, in which an ultrasonic transducer is coupled acoustically to the contact surface via a plurality of ultrasonic wave guides with equal delay times. The wave guides are thin and bendable, so they adapt to variations in the distance between the transducer and different parts of the contact surface by bending more or less. All parts of the irregular contact surface accordingly receive sound waves that are in phase, even when the contact surface is irregular, so a coherent sound wave is infused in the test specimen. The wave guides can be arranged in the form of an ultrasonic brush, with a flat head for coupling to a flat transducer, and free bristles that can be pressed against the test specimen. By bevelling the bristle ends at a suitable angle, shear mode waves can be infused into the test specimen from a longitudinal mode transducer.

Abstract: Apparatus for acoustically analyzing a structure having distributed characteristics comprising a first acoustic waveguide for transmitting an acoustic signal through a portion of the structure, a second acoustic waveguide for receiving a reflected acoustic signature of the structure and transmitting the acoustic signature to a sensor; the sensor producing an output that corresponds to the acoustic signature. The apparatus and methods are particularly adaptable to detecting distributed structural characteristics.

Abstract: For reducing the coupling liquid carried along during the performance of a test run of a device for testing gas carrying pipelines, the invention provides an ultrasonic gas carrying pipeline testing method, in which an overpressure is produced in a space containing a sensor carrier with ultrasonic sensors and a coupling liquid defined by the pipeline wall and scraper sleeves. An ultrasonic gas carrying pipeline testing device with a sensor carrier and a scraper sleeve positioned upstream thereof and connected thereto is characterized in that a connecting line (24) provided with a pump (26) passes from an area upstream of the scraper sleeve (22) to an area downstream of said scraper sleeve (22).

Abstract: A method for conducting an ultrasound procedure on an object having a target surface. The method includes the step of providing an ultrasound probe having an acoustical wave emitting end portion. A pad for transmitting acoustical waves between the ultrasound probe and a target surface of an object also is provided. The pad includes a first layer having a first porous portion which defines first layer pores therethrough. The first layer pores have a first layer pore dimension. The pad further includes a second layer having a first porous portion which defines second layer pores therethrough. The second layer pores have a second layer pore dimension. The second layer is attached to the first layer so as to define a space therebetween. The first porous portion of the first layer overlies the first porous portion of the layer. An ultrasound couplant is disposed in the space defined between the first layer and the second layer.

Abstract: The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

Abstract: An apparatus which measures a thickness of a layer using transverse waves of ultrasonic waves, and includes: a sensor unit having a probe for obliquely transmitting and receiving to and from the surface of a material to be measured having first and second layers with different acoustic impedances in a depth direction: an extractor for extracting, from a wave reception signal representing waves received by the probe, reflected waves from a boundary between the first and the second layers of the material; and a calculator for calculating a distance between the surface of the material and the boundary.

Abstract: A sensor, and a sensor object combination, makes possible the collection of vibratory data from an object while reducing extraneous data and making easier the obtainment of the data. The sensor comprises an elastomeric housing which includes a concave cup portion, and pick-up devices for collecting vibration signals. The concave cup portion comprises a suction cup which makes possible vacuum attachment of the pickup device to the object being tested. The data signal may be amplified, analyzed, and ultimately the data may be analyzed by a computer.

Abstract: A leakage-sound detecting apparatus is provided for efficiently detecting water leakage in a plastic pipe by increasing sensitivity to a low frequency sound component and efficiently reducing stray noise, as well as protecting a piezoelectric element. To this end a detection portion and a pedestal portion are connected through a mechanical resonant member formed of a soft material. A low frequency sound component is amplified by the resonant member, and high frequency components are substantially attenuated. In an alternative arrangement a detection portion and a mechanical resonant member mounted on a pedestal portion are connected through a buffer portion having a buffer member arranged therein. When a shock is applied to the bottom of the pedestal portion, due to the apparatus being dropped for example, the buffer member is compressed, and no overload is applied to a piezoelectric element.

Abstract: A transducer assembly and method for the ultrasonic inspection of tubing. An elastic membrane is used to form a reservoir of ultrasonic fluid coupled to ultrasonic transducers with the membrane conforming to the surface of the tubing being inspected. Guide wheels maintain the membrane out-of-contact with the tubing during relative rotational movement of the assembly and tubing during inspection. Water is introduced between the membrane and the tubing to provide ultrasonic coupling of the tubing to the transducers through the fluid of the reservoir.

Abstract: A measurement structure for determining the thickness of a specimen without mechanical contact but instead employing ultrasonic waves including an ultrasonic transducer and an ultrasonic delay line connected to the transducer by a retainer or collar. The specimen, whose thickness is to be measured, is positioned below the delay line. On the upper surface of the specimen a medium such as a drop of water is disposed which functions to couple the ultrasonic waves from the delay line to the specimen. A receiver device, which may be an ultrasonic thickness gauge, receives reflected ultrasonic waves reflected from the upper and lower surface of the specimen and determines the thickness of the specimen based on the time spacing of the reflected waves.

Abstract: An inspection apparatus and associated method includes a sensor housing defining an internal cavity in which a sensor is at least partially disposed for inspecting the surface of a structural part and for detecting defects in the surface and the substructure of the part. The inspection apparatus includes a plurality of compliant fibers extending outwardly from a first end of the sensor housing and circumferentially about an opening defined by the first end of the sensor housing. The compliant fibers support the sensor housing above the surface of the part and maintain the sensor in a predetermined position relative to the surface of the part. The plurality of compliant fibers are adapted to flex laterally to accommodate obstructions on the surface of the part, such as raised fasteners, doublers or lap joints while maintaining the sensor in the predetermined position relative to the surface of the part.

Abstract: A capacitor having two substantially parallel conductive faces is acoustically coupled to a conductive sample end such that the sample face is one end of the capacitor. A non-contacting dielectric may serve as a spacer between the two conductive plates. The formed capacitor is connected to an LC oscillator circuit such as a Hartley oscillator circuit producing an output frequency which is a function of the capacitor spacing. This capacitance oscillates as the sample end coating is oscillated by an acoustic wave generated in the sample by a transmitting transducer. The electrical output can serve as an absolute indicator of acoustic wave displacement.

Abstract: A set of ultrasonic probes for measurement of time of flight of ultrasonic pulses includes a housing (20), two transmitting ultrasonic probes (1, 2) and two identical receiving ultrasonic probes (9, 10) attached to the housing (20). The receiving ultrasonic probes (9, 10) are disposed between the transmitting ultrasonic probes (1, 2) and are disposed along one line with the transmitting ultrasonic probes (1, 2). Time t.sub.L of flight of wave pulse in the workpiece along the distance L between the receiving ultrasonic probes (9, 10) is calculated based on propagation time of a ultrasonic wave (7) transmitted by the transmitting ultrasonic probe (1) and received by the receiving ultrasonic probeheads (9, 10) and on propagation time of a ultrasonic wave (8) transmitted by the transmitting ultrasonic probehead (2) and received by the receiving ultrasonic probeheads (9, 10).

Abstract: A cooling block is provided for mounting a transducer or other electronic component on a test object which typically becomes heated during use or testing. The cooling block receives a flow of cooling gas and distributes the gas to flow outwardly past the transducer and maintain the transducer in relatively stable, constant temperature conditions. The cooling block also functions as a heat absorber. The block may be mechanically or magnetically attached to the object under test.

Abstract: An ultrasound probe housing has at least one air bubble trap disposed therein and configured to facilitate movement of air bubbles away from a window thereof and also configured to resist movement of the air bubbles back toward the window. Preferably, two air bubble traps are utilized, one proximate the ultrasound transducer and the other proximate the motor thereof, so as to facilitate isolation of the ultrasound transducer and motor from air bubbles. The air bubble traps are preferably configured as funnels having a narrow end thereof oriented away from the window and having a wide end thereof oriented toward the window such that air bubbles easily enter the wide end thereof but do not easily enter the narrow end thereof. The air bubbles preferably move to a fluid expansion compensation chamber wherein they become captured and provide compensation for thermal expansion of the ultrasound transmissive fluid contained within the ultrasound probe.

Abstract: A system for ultrasonic energy coupling includes an ultrasonic transducer, a horn member defining a passageway, and a pump for moving fluid through the passageway and outwardly of the horn. The method used to accomplish the energy coupling or transfer includes vibrating the horn member with an ultrasonic transducer and pumping fluid through the passageway in the horn member and onto an object.

Abstract: An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the MD and CD, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly.

Abstract: A solid, multipurpose, flexible, ultrasonic biomedical couplant hydrogel in sheet form is applied to the skin of a patient to facilitate the transfer of ultrasound energy between a standard ultrasound instrument and the body. The couplant sheet has broad upper and lower surfaces and a narrow peripheral edge which is usually circular, square or rectangular but can have other shapes such as the shape of the part of the body being monitored. During use, the lower surface of the sheet is applied to the skin of a patient and remain in place throughout use. The ultrasound instrument is then passed back and forth, usually in contact with the exposed upper surface of the hydrogel sheet while ultrasound energy is transmitted through the hydrogel which serves as a transmission path for the sonic energy passing to and from the body of the patient. The hydrogel sheet of the present invention is a flexible, self-supporting solid sheet which holds its form during storage and when placed on the body.

Abstract: Transducers are mounted in a housing or vessel to propagate signals along a fluid measurement path, and a plurality of massive elements are placed between transmitting and receiving transducers in the acoustic propagation path through the solid body of the housing or vessel to remove crosstalk. In a preferred embodiment, the elements are rings, or sleeves which are attached to, or are machined from a thicker cylinder to leave a thin-walled cylinder with alternating masses. An isolation structure lightly sandwiches a flange between O-rings. This structure may be formed with flanged transducer casings, allowing the transducers to be closely spaced in solid conduits or on rigid frames without ringing. Alternatively, it may be formed in a separate framework or holder, providing precise positioning for interrogating gases in unconfined or loosely confined regions. Closed path sensor configurations measure circulation or swirl.

Abstract: A bone assessment apparatus for transmitting and receiving measuring waves through a test part of a patient to diagnose the condition of the test part, includes a measuring bath containing a coupling liquid required for precise measurement and an immersion pouch for keeping the test part out of contact with the coupling liquid. The test part is inserted into the immersion pouch in the measuring bath without touching the coupling liquid. Even during the screening of a number of patients the coupling liquid is prevented, from being contaminated by the test parts of the patients and therefore it is not necessary to change the coupling liquid often. The use of the immersion pouch is detected by a detector to correct a deviation in diagnosis data obtained from the received measuring wave on the basis of a specific correction value assigned to each immersion pouch, thereby providing more precise diagnosis data.

Abstract: The need for a highly viscous couplant gel or water spray to form an acoustical couple for ultrasound testing is eliminated by employing an ultrasound probe module. A porous membrane and an ultrasound probe cooperate to define a chamber which contains a liquid acoustical couplant. When pressure is applied to the liquid acoustical couplant it passes through the porous membrane. The porous membrane and chamber are disposed such that ultrasound signals going to or away from the ultrasound probe pass through the liquid acoustical couplant and porous membrane.

Abstract: An ultrasonic probe suitable for acoustic-coupling via a water channel, includes a main element with a housing. Housed in watertight fashion in the housing is an ultrasonic oscillator, the oscillator being joined to a protective layer which is flush with the lower surface of the housing. The housing wall encloses a water channel which is connected at the input end to a hose connector and whose output end opens out in the lower surface next to the oscillator. The side wall of the housing immediately next to the lower surface has a physically interlocking coupling element for a nozzle with a matching physically interlocking coupling element to be fitted over the lower surface. The nozzle forms a truncated-conical channel which tapers towards its open end and which fits against the surface of the oscillator at the input end. The nozzle also has a blind-end bore, which forms an extension of the output end of the water channel, and a cross-channel between the blind-end bore and the channel in the nozzle.

Abstract: An ultrasonic piezoelectric transducer for monitoring acoustic events in a medium is disclosed. The transducer includes an elongated body member having a blind bore therein, a piezoelectric crystal which is received in the blind bore within the body member and which contacts the bottom surface thereof, and a rod which is received in the blind bore and which firmly contacts the piezoelectric crystal compressing the crystal against the bottom of the blind bore. The tip of the elongated body member has a convex configuration forming a lens permitting the interception of acoustic events over a wide angle and the direction of same toward the piezoelectric crystal for monitoring and detection purposes.

Abstract: Improved ultrasonic energy transducers each include a material contacting member secured to a piezoelectric element at an interface region between oppositely operated first and second regions of the piezoelectric element. The material contacting member intensifies and amplifies movement of the interface region as the first and second regions of the piezoelectric element operate in a push-pull mode relative to the interface region. The first and second regions of the piezoelectric element can be electrically driven to move the material contacting member for transmission of ultrasonic energy or mechanically driven by the material contacting member for receipt of ultrasonic energy. A variety of piezoelectric elements can be used in the improved transducers including, for example, generally rectangular bars and discs segmented into two or more portions. A variety of material contacting members can also be used including, for example, a cylindrical stud and a more narrow dowel.

Abstract: The invention relates to an acoustic emission transducer and a coupling method. The acoustic emission transducer (1) forms an assembly unit and is intended specially for measuring high-frequency acoustic emissions (up to about 2 MHz). It consists of a piezoelectric measuring element (9), an acoustic transmission base (8) with a circumferential coupling diaphragm (7), and an encapsulant (10) which partially encloses the measuring element (9). A mounting screw (3) serves to fix the transducer to a measuring object. The coupling diaphragm (7) lies in a recess (14) of the housing (2), whose bottom surface (5) is at a distance from the measuring object (15) corresponding to the prestressing distance s when the diaphragm (7) is unstressed.

Abstract: A method of and apparatus for continuous monitoring of the composition of a fluid mixture traveling through a conduit. The relative component concentration of the fluid mixture of a liquid/liquid or solid/liquid mixture is monitored with a non-intrusive ultrasonic apparatus. The relative component concentration of the fluid mixture is determined by measuring ultrasonic propagation parameters and temperature and comparing these measured parameters to calibrated data based on analytical measurements of samples of the process fluid mixtures. The calibrated data is obtained by measuring propagation parameters and analyzing process fluid mixtures at a different time from the measurements of process fluid mixtures.

Abstract: The invention is directed to a u/s test device for nondestructive testing of a workpiece moving relative thereto by the pulse echo method, having a fluid coupling between the ultrasonic oscillator and the surface of the work material. At least two test heads are provided whose sound beam axes intersect at a point in the region of the workpiece and a travel path in the form of a chamber is provided for guiding the fluid medium. To reduce susceptibility to interference and to achieve high test performance, a separately guided travel path extending along a determined length of the chamber and forming a duct (12-20) is associated with each test head (1-9), the axes of the travel path being aligned with the respective sound beam axis.

Abstract: An apparatus for acoustically inspecting a workpiece has a tubular member with a membrane sealing an end of the tube to form a first chamber. An acoustic transducer assembly is mounted in the tubular member. An adapter secured to the tubular member is adapted to contact the workpiece and space the membrane from the workpiece and form a second chamber. In operation, the transducer generates an acoustic wave that travels through coupling fluid disposed in the chambers to strike the workpiece. The acoustic wave is reflected from the workpiece, received by the transducer assembly, and a corresponding electrical signal is sent to a processor for evaluation. Additional features include a fluid conduit providing the independent coupling fluid, a spacer that accommodates workpiece surface variations while maintaining acoustic coupling with the workpiece, and a vacuum housing that removes excess coupling fluid from around the inspection apparatus and workpiece mating surface.

Abstract: An acoustic temperature and/or film thickness monitoring system for semiconductor wafers in which the velocity of acoustic waves in the wafer is employed to measure temperature and/or thickness.

Abstract: A method for coupling an ultrasonic probe to a test specimen, whereby a cushion of fluid is formed between the two bodies to facilitate the coupling. In order to optimize the coupling, reduce the quantity of coupling fluid as well as prevent a drain off of the coupling fluid, a vacuum is produced during the attachment of the probe to the test specimen at the end of the probe facing the surface of the test specimen. Coupling fluid is drawn by the vacuum into the gap between the probe and the specimen to form a fluid cushion. The device for coupling the probe to the test specimen is equipped with a guiding and retaining housing for the probe through which the fluid may be supplied to the gap between the two bodies in order to form the cushion of fluid. The gap between the two bodies is connected through channels in the housing to a vacuum source and a container for the coupling fluid.

Abstract: Sensor assemblies, comprising one or more sensors for use in high-temperature environments such as an aircraft wing, include a thermally conductive retaining member in thermal communication with either the sensor or the environment surrounding the sensor. A housing assembly placed proximate to, and in thermal communication with, the retaining member defines a fluid passageway. During operation, fluid circulates through the housing to enhance the transfer of heat away from the sensor. Such heat transfer facilitates maintaining a sensor environment within the tolerance range of the sensor, thereby facilitating monitoring of the pressure fluctuation (or other sensor parameter) during operation of the aircraft.

Abstract: An acoustic emission transducer consists of a resonant detection element (10) which is attached to the base-plate (16) by a small area in comparison to the overall surface area of the resonant detection element (10) where this area of attachment is positioned with respect to the wave motion during the resonance of the resonant detection element (10) so as not to have a significant effect on the resonant detection element (10) other than to physically couple the resonant detection element (10) to the baseplate (16) and introduce elastic waves from the baseplate (16) to the resonant detection element (10) at the desired frequency, while allowing damping materials (24) to be acoustically coupled to the larger part of the resonant detection element surface area to produce a resonant acoustic emission transducer having reproducible characteristics of resonant frequency and rate of damping.

Abstract: The flow rate of a high temperature fluid flowing through a conduit is measured by passing ultrasonic waves through the fluid. The ultrasonic waves are emitted from an emitter located at one side of the conduit and are received by a receiver located at an opposite site thereof. A first spacer is disposed between the receiver and the conduit, and a second spacer is disposed between the emitter and the conduit. The spacers isolate the receiver and emitter from the high temperatures and conduct the ultrasonic waves without changing the frequency thereof. A quick-release clamp clamps the emitter, receiver and spacers together against the conduit.

Abstract: A method and apparatus for ultrasonically characterizing a polymer melt flowing in a predetermined direction between two opposed parallel surfaces spaced from one another to define a gap filled with polymer are disclosed. Ultrasonic pulses are propagated through the polymer melt between the two surfaces in a direction normal to the direction of flow for interaction with the polymer, the ultrasonic pulses having a duration such as to prevent successive echoes from overlapping with one another while reverberating between the two surfaces. The time delay between two echoes exiting from the polymer melt and generated from each pulse having interacted with the polymer is continuously monitored while simultaneously monitoring amplitude variations of the two echoes, to provide output signals representative of ultrasonic velocity and attenuation in the polymer melt. These output signals are processed to obtain data comprising ultrasonic velocity and attenuation values measured simultaneously as a function of time.

Abstract: A soft membrane booted transducer for performing ultrasonic inspections of parts and components that have rough sound beam entry surfaces. These rough surfaces may be in the form of as-welded unprepared overlays, cladded components, as-cast parts, or other unprepared surfaces that tend to prohibit, or prevent, sound entry from normal, smooth, hard-surfaced transducer contacting shoes made from Lucite or similar materials. The booted ultrasonic transducer has a soft membrane boot for coupling the transducer to an uneven or rough sound beam entry surface. The soft membrane is made of a flexible material capable of transmitting ultrasonic waves. When pressed into contact with the uneven or rough surface of the object being inspected, the membrane flexes to generally conform to the shape of the contacted surface. Flexing of the membrane eliminates or reduces air gaps between the transducer and the object surface, thereby increasing the ultrasonic coupling between the piezoelectric element and the object.

Abstract: An annular sonotrode 5 vibrates at one of its natural frequencies, preferably about four nodes 33-36 equally distributed over its circumference. The vibrations introduced at the input 17 along axis 10 are outputted to a tool 6 along an axis 19 bent by 90.degree.. With this design even difficult to access workpieces can be efficiently machined with ultrasonics.

Abstract: An ultrasonic probe is housed in a probe housing filled with fluid under controlled pressure. The probe provides ultrasonic sound through the fluid to a bladder which presses against the interior of a rotor wall. Located along the periphery of the bladder, a fluid wiper/soaker conduit provides droplets of fluid to the wall of the rotor bore to minimize friction between the bladder and the rotor bore wall and provide an ultrasonic path between the bladder and the rotor wall.

Abstract: An ultrasonic measurement device and a method for a non-destructive evaluation of polymer composites having discontinuous fibers distributed therein. The device has one or a plurality of substantially matched pairs of transducers disposed on wedge shaped focuser and a relay, the focuser and relay each have their impedances substantially matched to that of the polymer composite being analyzed. The device is placed on a surface of the composite with the apexes of the focuser and relay in close contact with the surface.

Abstract: An ultrasonic transducer system includes a transducer coupler body made of a material that transmits ultrasonic waves therethrough and an ultrasonic transducer joined to a first portion of the transducer coupler body. A footprint face plate is joined to a second portion of the transducer coupler body. The first portion and the second portion are selected such that an ultrasonic wave can propagate therebetween through the transducer coupler body. The footprint face plate extends beyond the transducer coupler body and has a footprint contact face on one end thereof, with the width of the contact face being much smaller than its length.

Abstract: An ultrasonic testing machine has a rotor (20) which incorporates several probes (21 to 23) and which has a transmission device (26) with several channels for connecting the probes (21 to 23) to a stationary electronic control and analysis device (32). The rotor (20) contains more probes (21 to 23) than channels in the transmission device (26). All probes (21 to 23) are connected electrically to a first multipoint connector (24) and all transmission devices are connected electrically to as second multipoint connector (28). At least one interchangeable plug counterconnector (30) corresponding to these two multipoint connectors is present and contains connections for contacts associated with the channels of the transmission device (26) with contacts of connections for some of the probes (21 to 23).

Abstract: An intrusive mounting arrangement for an acoustic sensor includes an acoustic window and a flange assembly for mounting the sensor and window on a fluid tank, the flange assembly having a body portion configured to extend through an opening in the tank wall in a fluid-tight manner into the tank interior, the flange assembly having a body flange that is attachable to the tank wall; the body portion having a fluid passageway therein and a port that permits fluid in the tank to flow into the passageway; the flange assembly further comprising means for retaining the acoustic window in the passageway; the sensor comprising a body that is insertable in the fluid passageway in a fluid-tight manner; the sensor further comprising an active surface acoustically coupled to the window by fluid when the sensor is fully inserted in the passageway.

Abstract: A gas jet is positioned above the water nozzle of a system provided for ultrasonically detecting flaws in an article to be inspected. The water nozzle directs a substantially level water jet stream against an upright surface of the article as it is moved transversely of the nozzle. A transducer associated with the water nozzle transmits ultrasonic energy along the water jet stream toward the article, then receives echoes from flaws existing in the article. The gas jet directs toward the upright surface of the article a gas jet stream which is substantially parallel to, and vertically aligned with, the water jet stream. The gas jet stream serves to deflect the water splashing off the surface of the article after impact therewith and prevents the splashing water from descending toward and striking the water jet stream.

Abstract: An apparatus for determining the time taken for sound energy to cross a body of fluid in a pipe uses a modified pipe in which flat members seal apertures in the pipe and two transducers are attached to respective fiat members, wherein the material around each aperture curves away from the centre of the pipe towards the periphery of the aperture and contacts the respective flat member along the entire periphery of the aperture.

Abstract: A transducer for generating or detecting ultrasonic energy of very narrow bandwidth which closely approximates a monochromatic source or detector has a gas gap of uniform dimensional width. The transducer employs standing ultrasonic waves generated, by multiple reflections and constructive interference, within the gap, effectively acting as a filter to pass only ultrasonic waves having a predetermined resonant frequency in response to impingement of broadband ultrasonic energy. This filtering effect enables the transducer to act as a source or detector of monochromatic ultrasound.

Abstract: An ultrasonic transducer for measuring the travel time of ultrasonic pulses in a gas, in particular for a gas flow rate meter, includes a piezoelectric radial oscillator, which is preferably formed a piezoceramic and which has two sides and electrodes each being disposed on a respective one of the sides for receiving a spike pulse voltage. A first adaptation layer is applied to one of the sides of the radial oscillator. The first adaptation layer has a thickness being less than one-fourth of a characteristic wavelength of the transducer. A second adaptation layer is applied to the first adaptation layer. The second adaptation layer also has a thickness being less than one-fourth of the characteristic wavelength of the transducer. A damping body is mounted on the other of the sides of the radial oscillator. The radial oscillator and the adaptation layers form a sandwich executing a thickness oscillation as a consequence of a radial-thickness coupling, as soon as the spike pulse voltage is applied.

Abstract: In a process for ultrasonic testing of elongated, prism-shaped sections (22) with at least one planar outer surface (54) extending along the longitudinal axis (26) of the section, with the objective of detecting material defects or verifying geometric data, the section (22) to be tested is exposed to ultrasonic beams from several ultrasonic probes (28 to 34) installed in a probe carrier (44). The section (22) is moved along its longitudinal axis (26) in relation to the probe carrier (44). The latter is installed in the rotor (20) of a rotary testing machine which rotates around the longitudinal axis (26) of the section (22).

Abstract: A hard faced contact ultrasound transducer device for transmitting ultrasound pulses into a workstructure at temperatures substantially above room temperature comprises a ceramic protection block, a piezoelectric element bonded to the protecting block, a damping substrate adjacent the piezoelectric element, a ceramic clamping block with standoff portions that limit the approach of the clamping block toward the ceramic protecting block, and fasteners to draw the clamping block toward the protecting block forcing the damping substrate against the piezoelectric element and the protecting block.