Akademiet for De Tekniske Videnskaber, Svejsecentralen

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Akademiet for De Tekniske Videnskaber

Svend A Lund

Bent E Nielsen

Willy D Kristensen

Sven E Iversen

Allan Northeved

Knud Christian Fabrin

Poul Solfjeld

Erik Kongshavn

Palle Rasmus Jensen

Erik Ostgaard

Carl E Petersen

Jorgen Dam

Erik T Bogen

Thorkild Kristensen

Peter Krarup

A prior art computerized ultrasonic examination is performed by moving an ultrasonic probe over the surface of an object, transmitting short pulses of ultrasonic energy into the material. Combined digital position and echo pulse signals are electronically stored, processed, and used for the display of a first video sectional flaw image of a selected sectional plane through the object. Representatives of reflected echo amplitudes from a chosen location are now shown, either in said first flaw image, or in at least one separate sectional view, as lengths of line segments originating at an image pixel representing said location, and drawn in the directions of the projections on said selected sectional plane of the incoming pulses at said location. In typical examples it is demonstrated, how reflected waves can be visualized and evaluated, and how the corresponding flaw images can be superimposed on said first video flaw image, thereby adding important information which is normally disregarded in the prior art. This visualization can be made on line during the examination or in later post processing and closer analysis of the results of the examination.

Method of visualizing reflection characteristic in ultrasonic examination

A prior art computerized ultrasonic examination is first performed by moving an ultrasonic probe over the surface of an object, emitting short pulses of ultrasonic energy into the material. Combined digital position and echo pulse signals are electronically stored, processed and used for the display of video images presenting accumulated echo amplitude data in circular patterns associated with selected sectional planes through the object. The results of the examination are then analyzed and evaluated by means of a mathematical model, able to produce imaginary digital data simulating the progression and reflection of sound pulses emitted by the ultrasonic probe. Imaginary echo signals from imaginary point reflection sources corresponding to selected individual flaw image pixels are then compared with the actual echo pulse signals electronically stored, and in cases of identical sound path lengths, the corresponding actual echo pulse signals are deleted from the memory. By such successive elimination of individual flaw echo signals from the totality of echo signals received, it becomes possible to analyze complex flaw combinations in successively revised sectional images, removing individual flaw images one by one. The peak amplitude values of deleted echo pulse signals may further be re-stored, processed and used for the display of video sectional and projection flaw images of drastically improved quality and precision.

Method of analyzing and evaluating the results of an ultrasonic

System for ultrasonic examination

A system for the internal inspection of pipelines for carrying oil or gas, subsea or overland, includes an apparatus carrier, pressure-driven driven or self-propelled, carrying non-destructive examination apparatus moved through the pipeline to inspect the safety conditions of the pipeline wall material and surfaces. During its progression the carrier gradually deposits one or more expendable, thin optical fibers inside the pipeline. The fibers connect the carrier with a control station, situated outside the pipeline at the carrier launching end of the pipeline, through electro-optical signal converters installed in the carrier and in the control station. The system permits continuous on-line communication with the carrier over very long distances (1) for generating instant visual displays and permanent records of the step-by-step results of the inspection, (2) for controlling the functions of the non-destructive examination apparatus, and (3) for controlling the rate of progression of the carrier. Upon completion of the inspection the optical fibers are discarded inside the pipeline for later removal, if necessary, by a routine in-service cleaning operation.

System for the internal inspection of pipelines

In an improved method for determining the position of a measuring sensor or probe (1), such as a probe for ultrasonic examination of an object (2), use is made of at least two mutually crossing bars (3a, 3b, 3c) of electrically conducting material in constant sliding, electrical contact with each other. At least one bar (3a) is kept fixed in relation to the object (2) to be examined, and at least one bar (3b, 3c) is kept fixed in relation to the probe (1). By measuring the electrical voltage drops in the bars, the positions of the crossing points (4ab, 4ac) between these bars and thereby the actual position of the probe in relation to a reference system (x, y) on the surface of the object are determined. By using at least three bars, it is possible to determine the position coordinates (x, y) as well as the angular direction (v) of a freely movable probe in relation to objects to be examined having plane, cylindrical or double-curved surfaces. Since the method can be carried out completely without use of movable and, thereby, vulnerable and complicated mechanical or electrical elements, scanning systems based on the method can be made considerably smaller, simpler, cheaper and more robust and reliable in operation than systems hitherto known.

Method for determining the position of a measuring sensor or a probe

A three-dimensional ultrasonic scanning apparatus produces projection pictures on the surface of an object under inspection or examination and on planes perpendicular thereto. The amplitudes of the echo pulses produced by the ultrasonic scanning appartus, which uses an angle probe, are stored in a memory having at least one storage position relating to each projection of a reflecting point within the examined area. Only the highest echo amplitude originating from all the reflecting points lying on a projection line at right angles to the projection plane in question is recorded--not the highest amplitude from each reflecting point on the projection line. Thus, only those echo pulse amplitudes necessary to produce a projection picture of the object are stored in the memory thereby substantially reducing the required memory capacity.

Apparatus for recording echo pulses

In an apparatus for locating inhomogeneities in otherwise homogeneous bodies by the ultrasonic pulse-echo method an angle probe is used in connection with an acoustic signal emitter, adapted to produce an audible signal, a characteristic of which, e.g. the intensity, varies in a continuous manner with the amplitude of the reflected ultrasonic pulses.

Apparatus for ultrasonic examination

When carrying out electric fusion welding with at least two current-carrying electrodes, these electrodes are held in a joint holder in non-parallel positions so that they meet in a point of intersection in which melting of the electrode material takes place. Hereby the risk of burn-through is minimized and an additional degree of freedom which can be used for controlling purposes is obtained.

Method and an apparatus for automatic electric welding

An apparatus for providing an ultrasonic sectional view stating the proportion of meat and lard in biological material. The apparatus comprises a transducer unit and an ultrasonic pulse generator providing a periodically scanning window. Said transducer unit comprises at least two multi-crystal units, the longitudinal axes of which may form a variable angle. The joint between the multi-crystal units comprises an angle information unit. By means of said angle information unit and the means for visualizing reflected ultrasonic echoes it is possible to visualize marginal surfaces.

Apparatus for providing an ultrasonic sectional view stating the

It has previously been suggested to indicate, or record images of, internal inhomogeneities in a sample by means of an ultrasonic angle probe which is moved on the surface of the sample, the reflected echo signal being indicated as punctiform position markings in such a way that when added together the markings form an image of the projection of the inhomogeneities on the surface of the sample. It is now suggested that also the amplitudes of the echo signals are indicated, whereby much more information about the inhomogeneities is obtained. The amplitude can be indicated as a variation of the intensity, size and/or duration of the position markings. Another possibility is to indicate the amplitude by the length of a line segment.

Method and apparatus for ultrasonic examination

Method and apparatus are disclosed in which it is possible by means of ultrasonic examination according to the pulse echo method to obtain an indication, or a recording of images, of internal inhomogeneities in otherwise homogeneous bodies, corresponding substantially to the images obtained by producing a normal radiographic film of the body. To obtain this an ultrasonic angle probe is moved across the surface of the body and the echo signals are used to produce punctiform markings on a recording surface in such a way that (a) the markings are effected along a moving axis of indication, (b) the displacement of a reference point on the axis of indication follows the displacement of the sound emission point of the probe, (c) the direction of the axis of indication follows the direction of the projection of the sound path on the surface of the body, and (d) the distance from the reference point to each marking is proportional to the echo time of the corresponding ultrasonic pulse. Various methods of recording, including remote recording, are described.

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Birkerød, Denmark

Svend A Lund