The Babcock & Wilcox Company

Mcdermott Technology, Inc.

Bwxt Technical Services Group, Inc.

Other

Babcock & Wilcox Technical Services Group, Inc.

Babcock Wilcox Canada Ltd.

Bwx Technologies, Inc.

Daniel T MacLauchlan

Paul J Latimer

Jimmy W Hancock

Wayne M Latham

Bradley E Cox

Steven Paul Clark

Karl C Henderson

John H Flora

Charles B Overby

Nicholas J Borchers

Steven J Younghouse

Hubert L Whaley

Daniel P Geier

Kenneth R Camplin

Thomas Powers

Donald M Stevens

Paul John Berbakov

Donald W Morrison, Jr

William C Rutherford

Todd E Mitton

Ralph D Murphy

A method for efficiently achieving full-matrix ultrasonic data capture which includes the steps of providing an ultrasound array apparatus, the ultrasound array apparatus further comprising a probe, collecting data over a plurality of inspection locations, generating a plurality of data matrices, each of the data matrices reflecting data collected at the locations, and collecting, initially, a subset of a quantity of data needed for reconstruction of each of the inspection locations. In the method, as the probe moves from collection location to collection location, a data matrix at a prior collection location is gradually filled in as the probe moves to subsequent collection locations. In certain embodiments physical scanning of a probe with few elements is replaced by electronically scanning using an array with many elements.

Synthetic data collection method for full matrix capture using an ultrasound array

A method for ultrasonically inspecting components with wavy or uneven surfaces. A multi-element array ultrasonic transducer is operated with a substantial fluid layer, such as water, between the array transducer and the component surface. This fluid layer may be maintained by immersing the component in liquid or by using a captive couplant column between the probe and the component surface. The component is scanned, measuring the two dimensional surface profile using either a mechanical stylus, laser, or ultrasonic technique. Once an accurate surface profile of the component's surface has been obtained, data processing parameters are calculated for processing the ultrasonic signals reflected from the interior of the component that eliminate beam distortion effects and reflector mis-location that would otherwise occur due to the uneven surfaces.

Ultrasonic inspection method

An ultrasonic probe encircles the perimeter of a target component to be ultrasonically tested and has a base and a pair of jaws pivotally mounted to the base at opposite ends of an arcuate inner surface of the base to encircle a target component with arcuate inner surfaces of the jaws as well. The inner surfaces form a coupling fluid chamber with an outer surface of the target component. Front and rear sets of seals connected to and extending along front and rear portions of the arcuate inner surfaces seal the chamber so that it can retain a coupling fluid such as water. An arcuate set of ultrasonic transducers is connected along at least one but preferably all of the arcuate inner surfaces for transmitting ultrasonic signals to the coupling fluid chamber and into the target component.

Low profile encircling ultrasonic probe for the inspection of in-situ piping in immersion mode

An EMAT device for non-destructive inspection of the surface of a tube for cracks using acoustic surface waves includes a pulsed magnet having an active surface for facing the surface of a tube to be inspected. A receive emat coil is on the active surface and a transmit emat coil is on the opposite surface of the receive coil. The transmit emat coil has a scan surface for scanning over the tube surface. A transmitter for generating and transmitting an RF signal to the transmit emat coil is provided for generating a transmitted acoustic wave signal along the tube, the transmitted wave creating a reflected acoustic wave if a crack in the tube is encountered, the reflected wave generating a reflection signal in the receive emat coil. A receiver is connected to the receive emat coil for receiving the reflection signal. A digital computer is connected to the receiver for receiving and for processing the reflection signal and a display displays information about a crack in the tube which created the reflected acoustic wave and resulting reflection signal.

Electromagnetic acoustic transducer (EMAT) inspection of cracks in boiler tubes

An EMAT apparatus which non-destructively tests spot welds between two sheets of metal. The apparatus includes a first EMAT coil on one sheet that acts as a transmitter for generating and transmitting an acoustic wave signal toward the spot weld, and a second EMAT coil on the other sheet for receiving the acoustic wave signal and converting the received acoustic wave signal to an electronic signal having a waveform. Electronics and a PC are used to measure at least one parameter of the waveform which is indicative of a characteristic of the spot weld.

EMATS for spot weld examination

An EMAT arrangement utilizes separate transmitter and receiver EMATs which may each be connected to a tuning capacitor by a stripline cable. An electrostatic shield may also be provided between the coils and the coils can be offset from each other by &frac12; the pitch distance of sections in the coil. This reduces the duration of main bang, thus making it possible for the EMAT arrangement to detect structures which are very close to the coils.

Main bang recovery EMAT

A transmitting and receiving switch assembly for an electromagnetic acoustic transducer (EMAT) and a method for selectively switching an EMAT between transmit mode and receive mode both use a particular circuit. This circuit contains an EMAT coil coupled to a tuning capacitor, which allows the EMAT to be operated at a desired frequency when transmitting. A set of capacitors separates the EMAT coil from a set of diode strings (preferably containing at least one fast switching silicon diode), which are joined by a resistive connection. A transformer, which is center tapped at its primary winding, is coupled to the other end of the diode strings. Finally, a receiver input is connected to the transformer. In operation, the frequency of the EMAT is set by appropriately energizing and tuning the tuning capacitor. A voltage is then applied in the center tapped transformer and in the resistive link between the diode strings. The current automatically switches the conductivity of the diodes and permits the EMAT to switch modes as desired. Likewise, the method disclosed also utilizes this circuit, as described above, and involves several steps. First, the EMAT frequency must be selected and set, using the tuning capacitor. Then, a voltage is applied within the circuit to induce transmission by the EMAT. Next a sinusodial toneburst is given within the circuit to switch the transmit/receive capabilities of the EMAT, and then observing the input received by the EMAT-thereby permitting the alternate switching of the EMAT from receive to transmit mode in a matter of nanoseconds.

EMAT transmit/receive switch

An ultrasonic method for determining liquid level in a container employs an electromagnetic acoustic transducer (EMAT) to launch and receive longitudinal ultrasonic waves into a thin metal wall or thin metal foil seal of the container, causing it to vibrate and launch ultrasonic compressional waves into liquid contained therein. The compressional waves travel through the liquid contents and reflect off an interface, returning to the thin metal wall and causing it to vibrate in the presence of the magnetic field produced by the EMAT transducer assembly. This induces a voltage in the eddy current coil of the EMAT transducer assembly, and by measuring a time of flight of the ultrasonic compressional waves through the liquid contents, and by using a preestablished value for a velocity of the ultrasonic compressional waves within the liquid contents, the liquid level of the contents can be determined.

Method for determining liquid level in a container using an electromagnetic acoustic transducer (EMAT)

An EMAT testing device for nondestructively testing tubes for surface defects and displaying the results has a EMAT transmitter arranged collinear with a pair of EMAT receivers. The EMAT receivers each receive a pair of oppositely propagating circumferential acoustic surface waves from the transmitter at different times and the relative amplitudes of the received waves are compared to located defects adjacent the receivers in the tube.

Electromagnetic acoustic transducer (EMAT) inspection of tubes for

A method for inspecting welds uses a single EMAT tranducer operated in pulse-echo mode that sends and receives Rayleigh waves to detect defects in a weld between sheet plates of dissimilar thicknesses.

EMAT inspection of welds in thin steel plates of dissimilar thicknesses

A method for detecting the location of an edge, interface, seam or other structure of a workpiece uses one or two electromagnetic acoustic transducers (EMATs) to transmit an ultrasonic wave along the workpiece toward the edge and to receive a reflected wave. The velocity of the wave in the material is used in conjunction with the round trip time-of-flight (TOF) of the transmitted and reflected wave, to calculate the location of the edge. This is done by placing the transducer or transducers at known locations on the workpiece. A surface wave or 90 degree shear wave can be utilized and no contact is needed between the transducer and the surface of the workpiece. Rough and/or dirty surfaces and hostile environments can be accommodated while practicing the invention.

Edge detection and seam tracking with EMATs

An EMAT arrangement utilizes separate transmitter and receiver EMATs which may each be connected to a tuning capacitor by a stripline cable. An electrostatic shield may also be provided between the coils and the coils can be offset from each other by 1/2 the pitch distance of sections in the coil. This reduces the duration of main bang, thus making it possible for the EMAT arrangement to detect structures which are very close to the coils.

An ultrasonic inspection technique using a specially designed electromagnetic acoustic transducer (EMAT) launches and receives longitudinal ultrasonic waves into a thin metal wall or thin metal foil seal of a container, causing it to vibrate and launch ultrasonic compressional waves into liquid contained therein. The contents of plastic containers having a metal foil seal forming one wall are easily inspected. The EMAT establishes a magnetic field in the surface of the metal parallel to the surface. Radio frequency (RF) eddy currents are also induced by the EMAT in the surface of the metal. A Lorentz force is generated in the metal surface according the vector product of J, the current density, and H, the magnetic field, and the force generated by the interaction of the perpendicular components of the magnetic field H and the eddy currents J is directed normally to the surface of the metal. This normal force oscillates with the frequency of the induced eddy currents creating ultrasonic compressional waves which propagate normal to the surface of the metal. In such thin-walled metal containers or thin metal foil seals, where the thickness of the metal is much shorter than the ultrasonic wavelength in the metal, the generation and reception process is analogous to the operation of a loudspeaker in air. In this application, the thin metal wall or foil acts as a membrane, with the Lorentz forces generated in the wall or foil causing the metal membrane to vibrate, generating ultrasonic waves in the liquid. Because the thin wall or foil is much more compliant than a thick piece of metal, much larger displacements are generated at the metal-liquid interface than for the thick-wall case, resulting in much larger signal amplitudes than in the thick-wall case.

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Lynchburg, VA, United States of America

Daniel T MacLauchlan