Abstract: A device for measuring a distance between a panel and a shadow mask included in a color CRT (Cathode Ray Tube) of the present invention includes a range finder having an emitter for emitting an ultrasonic pulse, and a receiver for receiving it. The emitter emits the ultrasonic pulse toward the inner surface of the panel on which the shadow mask is mounted. The distance or so-called Q value is measured on the basis of a lag between the time when a first reflection from the shadow mask reaches the receiver and the time when a second reflection from the inner surface of the panel reaches the receiver. The device is capable of measuring the Q value without resorting to the removal of the shadow mask, and measuring Q values even smaller than 5 mm without contacting the shadow mask. In addition, the device is easy to handle and small size.

Abstract: A non-destructive method of determining substrate tilt within a packaged component includes providing the packaged component (10) with a component surface (32), providing a substrate (22) in the packaged component (10) wherein the substrate (22) has a substrate surface (33), using an acoustic wave (50) to measure a distance (34) between the component surface (32) and a region on the substrate surface (33), using another acoustic wave (53) to measure another distance (35) between the component surface (32) and a different region on the substrate surface (33), and comparing the distances (34, 35) to a threshold value.

Abstract: An on-line ultrasonic sensor for monitoring and sensing failure in a cutting tool insert. The preferred embodiment of the sensor includes a piezoelectric film of aluminum nitride (AlN) deposited onto a tool insert or tool insert seat with the AlN film electrically connected to a signal generator and detection circuitry. A voltage pulse is applied to the AlN film to generate ultrasonic signal pulses in the AlN film which are transmitted through a tool insert to the vicinity of the cutting edge of the tool insert during use. Back-reflected ultrasonic signals from the edge of the tool insert induce a voltage signal in the piezoelectric film which is analysed and compared to signals characteristic of undamaged tool inserts. Temperature increases, wear and various types of tool failure can be readily detected during use of the insert with the sensor.

Abstract: A method and apparatus for ultrasonic imaging which includes scanning a test specimen located in a test fixture in a predetermined scan pattern. Propagating and receiving reflected pulses of ultrasonic energy from an ultrasonic transducer directed to a surface of the test specimen. Detecting and generating data of both the amplitude and the depth of a defect in the test specimen from the pulses received from the test specimen. Merging the data of the amplitude and the data of the depth of the defect into composite data and then displaying the composite data in a three dimensional image whereby a mesh of both amplitude and depth data of the defect is displayed in a single image of the defect.

Abstract: The presence of bubbles on such photographic material, as is well known, results in significant defects in the photographic materials produced so that it is important, in the manufacture of such photographic materials, to detect the presence of such bubbles in the liquid emulsion and to take appropriate remedial action. Described herein is a bubble detector comprising a conduit for liquid to be monitored, the conduit having opposing flattened, generally parallel walls, and a transducer engaged with one of the generally parallel walls and operable to apply alternating displacements to one of the generally parallel walls, at an ultrasonic frequency, in a direction generally normal to the generally parallel walls to transmit sonic or ultrasonic waves through liquid passing through the conduit.

Abstract: An apparatus to determine if an echo signal shown on a multi-echo analog display unit that is produced by an ultrasonic animal backfat measuring and analyzing instrument is an accurate indication of the depth of backfat under measurement. This display unit has a small hand retainable switch to freeze the signal under measurement to allow the analyzing portion of the instrument to send a signal to the display unit to inscribe a graphical overlay indication upon the echo signal. If the overlay indicator passes through the strongest one of the echo signals then the echo signal is thereby identified as being an accurate measurement of the animal backfat. If it does not, this indicates that something has interfered with this signal and it is therefore inaccurate.

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 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: When an ultrasonic transducer for detecting flaws in metal plates or the wall of a metal cylinder is directed at a surface to be inspected at a particular angle, about ten percent of the signal will appear as Harris waves which propagate into the test plate at ninety degrees to the surface. This signal which propagates vertically is polarized, with the result that the signal has a greatly improved signal to noise ratio. For an incident medium of water and employing shear wave refracting in the medium of cast iron the specific angle is approximately 33 degrees from the vertical for best signal to noise ratio. For steel the specific angle is approximately 31 degrees and is about 50 degrees for brass. Shear or longitudinal waves can be employed to affect the detection of subsurface defects with the particular angle changing depending on the relation of the velocity of the sound waves in the refracting medium to the velocity of sound waves in the incident medium.

Abstract: An ultrasonic inspection method for measuring the thickness of non-welded (non-metallurgically bonded) cladding on the inside surface of a vessel from an outside diameter surface of the vessel relies upon the occurrence of a phase change at an interface between the base metal and cladding layers to precisely determine its presence and location. By measuring the length of time for the ultrasonic pulse to propagate through the cladding material, suitable predetermined calibration standards for the cladding material in question can be used to convert the time of flight of the ultrasonic pulses through the cladding into a thickness of the cladding. The cladding thickness can be measured from an outside surface of the vessel whether or not it is empty and/or without stopping the process and/or draining it, and the method can even be employed at elevated temperatures through the use of known delay lines.

Abstract: New physical principles are used to determine the number of inventory goods on a store's display shelves. One principle involves transmitting waves (mechanical, sound or ultrasound) thru an unknown number of goods resting on an insulated plate. Another principle to determine the unknown mass is the inertial response caused by mechanical vibration. By measuring the reflected waves or response time, a computer or processor can determine the steady state condition. For the absorption method, the device receives waves and determines when the phase angle difference (between the transmitter's wave profile and the receivers' average wave profile) is zero. This zero phase angle means a standing wave exists in the insulated plate and its goods. By subtracting the intensities of the waves (transmitter minus receivers' average) the total absorption energy can be determined.

Abstract: The depth of a case on a specimen of case-carburized steel is measured by launching an acoustic wave along the surface of the specimen such that the wave passes through the case, and measuring the velocity of that wave within the specimen. From an existing correlation of velocity and case depth for the very same core steel as the specimen, one finds the case depth which corresponds to the measured velocity, and that is the case depth of the specimen.

Abstract: The concentration of cavities in a formed product formed by superplastic forming is measured based on a propagation velocity of ultrasonic waves in the formed product. An ultrasonic measuring head which oscillates and receives ultrasonic waves is brought into contact with the formed product. A measurement is made of the propagation time required for the ultrasonic waves to be incident from the ultrasonic measuring head on the formed product to return to the ultrasonic measuring head upon reflection from a rear surface of the formed product. The propagation velocity is obtained from the measured propagation time and the thickness of the formed product.

Abstract: A system and technique for measuring the thickness of an optical element. A first energy signal of a first phase is transmitted into the element. The first signal reflects off of a distal surface of the element and is detected as a return signal. The phase of the reflected signal is compared to the phase of the transmitted signal and the frequency varied to extract a third signal representing a desired phase difference therebetween. Corresponding frequency data are processed to determine the thickness of the element at the point of transmission of the first signal.

Abstract: An apparatus and method for ultrasonic inspection of a conduit are provided. The method involves directing a first ultrasonic pulse at a particular area of the conduit at a first angle, receiving the reflected sound from the first ultrasonic pulse, substantially simultaneously or subsequently in very close time proximity directing a second ultrasonic pulse at said area of the conduit from a substantially different angle than said first angle, receiving the reflected sound from the second ultrasonic pulse, and comparing the received sounds to determine if there is a defect in that area of the conduit. The apparatus of the invention is suitable for carrying out the above-described method. The method and apparatus of the present invention provide the ability to distinguish between sounds reflected by defects in a conduit and sounds reflected by harmless deposits associated with the conduit.

Abstract: A mechanical contour follower is disclosed for maintaining a transducer ninety degrees to a workpiece surface, with respect to longitudinal and transverse axes of the workpiece surface, and for keeping the transducer at a constant distance from the workpiece surface during an ultrasound inspection of the workpiece (these conditions being referred to as keeping the transducer normal to the workpiece surface).

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 transfer device an ultrasonic sensor having an oscillating section for oscillating an ultrasonic beam toward wafers which are horizontally arranged in a carrier and a receiving section for receiving a reflected ultrasonic wave, and driving mechanism for vertically moving the ultrasonic sensor relative to the carrier so as to sequentially radiate an ultrasonic beam to the end faces of the wafers. The presence/absence of a wafer and projection of the wafer in and from the carrier are detected based on the reflected wave received by the receiving section.

Abstract: A scanner head for ultrasonic testing of structures includes a carriage with rollers supporting the carriage for movement over a surface being tested in a selected direction. A transverse frame is supported by the carriage and extends in a second direction crossing the one direction. A transducer is supported by the frame for movement along the frame to preset operative offset positions. For pipes or boiler tubes, the frame is in the form of an arc bar having a T-slot in which a holder for the transducer rides. With the carriage moving axially of the tube or pipe along a reference line, the arc bar keeps the transducer perpendicular to the surface regardless of the offset position. The rollers drive a distance increment signal generator to pulse the transducer and drive the ultrasonic transceiver and display circuitry.

Abstract: A method for ultrasonically inspecting the surface of a bore, particularly the bore of a railroad wheel axle, includes the step of generating a transverse ultrasonic wave from an emitter which interacts with the surface of the bore, and comparing the amplitude of the echoes obtained with values obtained from a calibration curve plotted for a bore having a standard defect which corresponds to the bore to be inspected so as to determine the existance of a defect when the amplitude of the echoes is greater than a specified fraction of the value indicated by the calibration curve. A corresponding device is provided for ultrasonically inspecting the surface of the bore of the railroad wheel axle.

Abstract: The present invention provides a method of measuring the depth of a dicing groove capable of measuring the depth of the groove with a high accuracy when the groove is cut in a full-cut mode, which method employs an ultrasonic detector which emits ultrasonic waves, measures the time interval between the emission of the ultrasonic waves and the return of their echo, the phase difference between the emitted ultrasonic waves and the reflected ultrasonic waves, or both the time interval and the phase difference to measure the depth of the groove, and is featured by determining the depth of the dicing groove on the basis of the depth of the groove formed in an exposed area of the adhesive sheet not occupied by the workpiece.

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: A self-contained, portable, hands free, one man ultrasonic test view is disclosed. The system can include a variety of features including a semiautomatic scanner for positioning a probe at various locations within a selected region of a specimen that is powered only in one axis with the second axis being manually advanceable by the user. A second feature is a display that is mountable in front of one eye so that the user of the system can simultaneously view the displayed ultrasonic response signal with one eye while viewing the specimen with the other eye to mentally superimpose the one on the other. Another feature is the inclusion in the processor of a voice recognition device to detect and translate voice commands to select and control the operations of the processor together with a microphone for the user to deliver voice commands to the system.

Abstract: In a method for the early detection and location of a change in a component of a turbine, in particular in a turbine blade, in the event of a deviation from a standard value in at least one measured value determined during operation of the turbine, an acoustic spectrum generated by the component is measured in the interior of the turbine and compared with a reference spectrum. In order to increase the intensity of signals in the acoustic spectrum, the components of the turbine, preferably runner blades, are excited from outside to acoustic emission (resonance test). An apparatus has a number of sensors for recording operating parameters of the turbine. The sensors are connected to a device for measured value conditioning. In order to detect and locate changes, an acoustic measurement probe which can be inserted from the outside into the interior of the turbine, is connected to the device.

Abstract: A method for detecting defects with a surface ultrasonic wave in which a surface ultrasonic wave probe is brought into contact with a surface of a rotating cylindrical member via a thin film of a contact liquid medium such that a contact trace of the probe extends linearly or helically about the circumference of the cylindrical member. An ultrasonic wave propagates in the surface portion of the cylindrical member from the probe in an opposite direction to the rotational direction of the cylindrical member. The probe is provided in a front portion thereof with a projection slightly extending downward from a lower surface of the probe so that the thin film of the contact liquid medium is stably formed. There is substantially no thin film of the contact liquid medium on the surface portion of the cylindrical member in which the surface ultrasonic wave propagates.

Abstract: A method of quality control for targets intended for use in the sputtering process. A test parameter is established by immersing the target in a tank of liquid, irradiating the target with ultrasonic energy in the Rayleigh frequency range, and integrating the portion of the ultrasonic energy which passes through the target and reflects off the back wall. This test parameter is closely related to the uniformity of a film which may be sputtered from the target onto a substrate.

Abstract: An ultrasonic testing method for detection of flaws in a ball-shaped material to be tested using an ultrasonic probe, wherein a test frequency f (MHz) of the probe and a radius of curvature r (mm) of a tip portion of the probe satisfy the relationship 50 mm.ltoreq.r.sqroot.f.ltoreq.60 mm, and wherein the radius of curvature r (mm) of the tip portion and the diameter D (mm) of an oscillator of the probe satisfy the relationship 0.35 mm.ltoreq.D/r.ltoreq.0.50 mm. The method enables detection of surface and internal flaws in materials, particularly ceramic ball hearings having a diameter ranging from several tens of millimeters down to 10 mm or below.

Abstract: An ultrasound transceiver providing enhanced imaging by selective filtering of the received signal to provide a variable frequency, constant bandwidth filtering of the received echo signals. The resulting signals are then detected to produce a signal, which when displayed, has a reduced number of false multiple images and enhanced signal quality from the deeper tissue discontinuities. Additionally, the received signal is detected in quadrature by reference to a simulated carrier pilot tone having a nonconstant frequency relationship to the transmitted signal. The resulting signal is post-processed to provide information which is used to display structural features, and in addition, the velocity profile of blood flow. The structure and velocity image information is superimposed to provide a composite signal wherein the static and dynamic characteristic of a patient is completely reported to the observer.

Abstract: Presented is a method and apparatus for inspection through use of a variable angle ultrasonic transducer of metallic members such as pipes, conduits, plates and other formed metallic members normally having a surface regularity adhering to a predetermined standard of normalcy. Inspection proceeds in such a manner that irregularities in the surface of the member under test that lie outside the standard of normalcy are sensed, the degree of irregularity determined and converted into an electrical signal that is applied to continually variably control the angular relationship of the ultrasonic transducer with the surface of the metallic member being inspected whereby abnormalities within the metallic member may be reliably and accurately detected, displayed and recorded.

Abstract: In an ultrasonic imaging apparatus, an object to be inspected is scanned while being irradiated by a generated ultrasonic beam. Echo signals from the object are received and a plane image and a cross-sectional image formed from the received echo signals are displayed. A marker indicating the focus position of the ultrasonic beam and a marker indicating the setting range of a detection gate are synthesized and displayed on the cross-sectional image. The plane image of the portion assigned by the focus position and the depth range on the cross-sectional image is obtained.

Abstract: An ultrasonic measuring device that is especially suited to nondestructive testing of materials is fitted with an ultrasound test head 72, a transmitter (74) and a receiver (76) that is characterized by a broadband logarithmic amplifier (78). This amplifier consists of several amplifier stages that are identical in construction and connected in series. Each amplification stage is characterized by the fact that it contains two transistorized individual amplifiers, namely a first and a second differential amplifier that are connected to one another and whose transistors (20, 22; 24, 26) are each interconnected at their base and at their collector. Each of these transmitters is connected at the emitters via inverse feedback resistors (34, 36; 40, 42) to a constant-current source (46, 50).

Abstract: In a blown film extrusion system in which film is extruded as a tube from an annular die and then pulled along a predetermined path, an apparatus is provided for gauging and controlling the circumference of the extruded film tube. At least one transducer, preferably ultrasonic, is mounted adjacent the extruded film tube for transmitting and receiving interrogating pulses along paths normal to the extruded film tube, and for producing a current position signal corresponding to the circumference of the extruded film tube. The current position signal is continuously compared with at least one previous position signal, preferably with a computer program resident in a controller memory. If at least one preselected condition is violated, the current position signal is disregarded in favor of an estimated position signal.

Abstract: A light weight hand held ultrasonic scanner for ultrasonic flaw detection systems utilizes an omnidirectional rolling ball element which drive optical encoders for X-Y coordinate position location of flaws. The rolling ball element is mounted in a body for rolling contact with a surface to be inspected. An ultrasonic transducer is mounted at one end of a second hollow body attached to the first body. An ultrasound reflector is provided in the hollow body to reflect an ultrasound beam transversely out of the second body.

Abstract: A method of an apparatus for ultrasonic inspection of multi-layered structures having acoustic transmission (I, III, V and VII) and reflection (II, IV, VI and VIII) frequency bands. Variations in one or more parameters of specific layers are largely restricted to specific frequency bands of said layers. By analyzing transmitted or reflected signals with respect to the frequency bands of the structure, interpretation of signals due to parameter variations as caused by voids, inclusions or delaminations can be effectively eliminated. The method is preferably used for the inspection of laminated structures consisting of metal layers bonded by fibre reinforced resin layers.

Abstract: The remote inspection of seam welds in reactor vessels is improved through the utilization of a pulser network which is inductively isolated from the transducer circuit to which it applies an excitation signal. Through the utilization of a step-up transformer, the pulser network may perform in conjunction with linear d.c. power supplies of lower voltage rating. The inductive coupling between circuits also serves to provide for the positive communication off of switching devices such as SCRs employed for excitation signal triggering. To avoid ground path induced noise, a different ground path is employed for the pulser network as for the transducer circuit. The transducer circuit ground path is that associated with a manipulator and, for example, a reactor vessel itself. Thus, the transducers employed may come in contact with the surface of the vessel being inspected. In similar fashion, an inductive coupling is provided between the transducer circuit and a pre-amplfying receiver circuit.

Abstract: Ultrasonic apparatus that automatically adjusts the focus of ultrasonic waves to a desired depth within an object includes an ultrasonic probe which irradiates a focused ultrasonic beam onto an object to be inspected and a receiver which receives ultrasonic waves reflected from the object. A desired focusing depth is set and the inherent focal length of the probe and the velocity of sound within the object are detected to evaluate a distance between the probe and the object at which the focus of the probe coincides with the desired depth. The distance between the probe and the object is adjusted to coincide with the evaluated distance.

Abstract: A method and apparatus for testing wire and, more specifically, testing the wire thickness and the wire roll of a trolley wire. The apparatus includes a jig assembly connected to a data acquisition system carried by a mobile unit. The jig assembly includes a transducer probe which transmits and receives an ultrasonic signal and an encoder which provides a pulse train corresponding to distance traveled. The ultrasonic signal is transmitted into the trolley wire and a reflected wave is received. The data acquisition system includes an ultrasonic scope, an analog to digital converter, a central processing unit, and a divider circuit. The ultrasonic scope provides a time analog signal based on the time of flight comparison between the transmitted ultrasonic signal and the reflected wave. The time analog signal is converted to a digital signal through an analog to digital converter. A trigger pulse is provided by a divider circuit based on a predetermined number of pulses from the encoder.

Abstract: A system and method is disclosed for measuring thickness of at least one film on a substrate by propagating an acoustic wave through the film on a substrate such that echo waves are generated and received by a transducer. An output signal is generated and processed to give a thickness value. The thickness valve is obtained from the time lapse between the propagated wave and receipt of the echo wave; by the frequency domain of the echo wave; or the phase of the echo wave.

Abstract: A method of ultrasonic inspection of a reactor nozzle involves positioning emitter and receiver transducers on the exterior vessel wall near the nozzle. The emitter transducer is positioned and oriented so that it generates both primary longitudinal and transverse beams. The primary longitudinal beam is directed at the inner radius of the nozzle. The transverse beam is directed toward the interior vessel wall at an angle of about 30.degree. to the normal. Most of the energy of the transverse beam is converted to a secondary longitudinal beam also directed toward the inner radius of the nozzle. The receiver transducer is positioned on the exterior vessel wall about 4" from the emitter transducer so as to be able to detect reflections of both the primary and second longitudinal beams from any potential defect in the nozzle volume adjacent the inner radius.

Abstract: An apparatus and method for aiming an ultrasonic transducer is disclosed. A tubular member having an axial bore with the transducer extending therein has an upper section, and a lower section with a threaded outer surface and an inner receiving surface. A ferrule assembly includes a compression nut mating with the threaded surface, and a ferrule biased by the compression nut against the receiving surface to form a waterproof seal with the transducer. A collar having a first annular section is detachably mounted coaxially on the tubular member. The first annular section extending to a second annular section having cut-outs suitable for providing access to manipulate the compression nut. The second annular section extending to a third annular section having a positioning members facing a section of the transducer extending from the tubular member.

Abstract: The duplex tube (1) comprises a tubular core (2) and a cladding or covering layer (3) made from an alloy, the base metal of which is identical to the base metal of the alloy constituting the tubular core (2).

Abstract: An ultrasound imaging system and method for examining the interior of an object. The imaging system includes an apparatus for transmitting and receiving ultrasound waves. A receiver amplifies echo signals from over a range of depths from within the object and generates electrical signals, each having a spatial spectrum. The imaging system also includes a compensation apparatus which compensates the spectral distribution of the signal by sweeping the spectrum of the signals in accordance with the depth from which the echo signals are reflected. In the currently preferred embodiment, the compensation apparatus sweeps from the low frequencies to the high frequencies of the spectrum.

Abstract: A transducer device for an ultrasonic flaw detection system comprises a right angle rectangular block with one longitudinal edge being shaped to accurately conform to the curvature of the surface to be inspected. An ultrasonic sound wave beam in the block is reflected 90.degree. by a rotating mirror to cut a 360.degree. arc path through the surface to be inspected.

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 for measuring a parameter of the object, and a mounting assembly removably mounted in the longitudinal and transverse bores of the wall and removably mounting the transducer in the transverse bore such that the first end of the transducer communicates with the cavity and a second end of the transducer communicates with the exterior of the receptacle.

Abstract: An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

Abstract: An ultrasonic probe for ultrasonically testing screws includes an ultrasonic transducer array having a plurality of ultrasonic transducers. The ultrasonic transducers selectively operate as transmitters and receivers. Coupling bodies of solid material are each acoustically coupled to a respective one of the ultrasonic transducers. Each of the coupling bodies have a free coupling surface facing away from the respective ultrasonic transducer. The coupling surfaces are adapted to the shape of the surface of a head of a screw to be tested. The coupling surfaces are centered on the head of the screw. A method for operating an ultrasonic probe includes placing and centering the coupling surfaces on the surface of the head of the screw. Different ultrasonic transducers are operated in at least one of transmission and reception modes in each of a plurality of measuring steps, for locating and characterizing a flaw in the material of the screw.

Abstract: An ultrasonic detection system having a flat faced radiator for providing a narrow beam of ultrasonic energy with minimal dispersion. The system includes an ultrasonic transmitter and receiver unit coupled to an ultrasonic transducer for producing ultrasonic energy. The system also includes a planar radiator and a coupling device between the ultrasonic transducer and the planar radiator. An encapsulating member surrounds the ultrasonic transducer for damping ultrasonic energy transmitted by the transducer in all but one direction. The encapsulating member is also coupled to the planar radiator in areas of the planar radiator that are not coupled to the coupling means. The encapsulating member has an area of increased density immediately adjacent to the planar radiator for damping the ultrasonic energy in areas of the planar radiator that are not directly coupled to the coupling means.

Abstract: In a blow film extrusion system in which film is extruded as a tube from an annular die and then pulled along a predetermined path, an apparatus is provided for gauging and controlling the circumference of the extruded film tube. At least one transducer, preferably ultrasonic, is mounted adjacent the extruded film tube for transmitting and receiving interrogating pulses along paths normal to the extruded film tube, and for producing a current position signal corresponding to the circumference of the extruded film tube. The current position signal is continuously compared with at least one previous position signal, preferably with a computer program resident in a controller memory. If at least one preselected condition is violated, the current position signal is disregarded in favor of an estimated position signal.

Abstract: A log harvesting system is disclosed in which the log is graded automatically in the field by ultrasonic testing of the log. Pulses of utlrasonic waves are transmitted into the log to detect internal defects within the log by measuring changes in the transient time of the ultrasonic wave pulses through at least a portion of the log. A computer is used to determine the grade of the log and produce a grade output signal from transient time data and signals related to the length and diameter of the log. The log is marked with a different colored paint to indicate its grade by an automatic marking device in response to the receipt of the grade output signal. Ultrasonic testing apparatus may be added to a tree harvesting head with a saw for felling the tree and cutting the log to the proper length and delimber knives for removing limbs, in order to test the log for defects as the log is conveyed through such head.

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