US3916675A - Deflector for converting a beam of parallel rays into a beam of rays having constant incidence on cylindrical part - Google Patents

Deflector for converting a beam of parallel rays into a beam of rays having constant incidence on cylindrical part Download PDF

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US3916675A
US3916675A US535703A US53570374A US3916675A US 3916675 A US3916675 A US 3916675A US 535703 A US535703 A US 535703A US 53570374 A US53570374 A US 53570374A US 3916675 A US3916675 A US 3916675A
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deflector
generating
lines
rays
angle
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Jean Perdijon
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/221—Arrangements for directing or focusing the acoustical waves
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/18—Methods or devices for transmitting, conducting or directing sound
    • G10K11/20—Reflecting arrangements

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  • ABSTRACT A deflector for exciting Lamb waves at the surface of a cylindrical part having a polygonal or circular directrix converts a beam of rays parallel to the generatinglines of the part into a beam of rays which impinge upon the surface at a constant angle of incidence in a family of broken helices.
  • the deflector comprises a plurality of flat deflecting elements each associated with one face of the part and having an orientation defined by the direction of a normal.
  • the planes of two flat deflecting elements are deduced from each other by a movement of rotation about a parallel to the generating lines followed by a movement of translation parallel to the generatinglines of the part.
  • This invention relates to a deflector in which the shape of the deflecting surface is such that a beam of parallel rays emitted by a radiation source and deflected by the deflector impinges upon a cylindrical part at a fixed and constant angle of incidence, said angle being measured with respect to the normal to the lateral surface of the cylindrical part at the point of impact of the ray.
  • the invention relates in particular to an ultrasonic deflector for reflecting the rays which are emitted by an ultrasonic transducer and intended to impinge upon a cylindrical part and to excite waves therein; said waves propagate within the cylindrical material and are diffracted by the flaws which are present in the part and modify the propagation of the diffracted wave; said diffracted wave is received by the transducer which performs the function of a receiver and thus makes it possible to detect the positions of said flaws.
  • the deflector in accordance with the invention finds a preferential application in the deflection of ultrasonic rays but is also applicable to the deflection of all electromagnetic or corpuscular rays.
  • ultrasonic detection entails the use of measurements either of velocity or of attenuation.
  • Ultrasonic detection of flaws is usually carried out by propagating ultrasonic wave trains through the material or by inducing ultrasonic vibrations in the material and collecting the echos which resuit from the presence of said flaws.
  • a technique which is commonly employed for solid tubes having cylindrical shapes of revolution consists in using two transducers whose movements are coupled for helical scanning; these two transducers are placed in a tank filled with water:
  • one transducer is located in a meridian plane of the tube and its axis is inclined with respect to the normal in order to carry out preferential detection of flaws having an orientation at right angles to the axis of the tube; these flaws will be designated hereinafter as transverse flaws,
  • the other transducer which is located in an equatorial plane has an axis which is not concurrent with that of the tube in order to carry out preferential detection of flaws having an orientation parallel to the axis of the tube (longitudinal flaws).
  • Lamb waves are waves which propagate parallel to the surfaces of the material: the entire thickness of the material begins to vibrate and this permits detection of flaws independently of the depth at which these latter are located.
  • these waves are modes inherent to the geometrical configuration in which they are generated and can be excited in a material of given thickness and at a given frequency only in respect of well-determined angles of incidence of the exciting ultrasonic waves.
  • the angle of incidence of excitation of the Lamb waves corresponding to the fundamental anti-symmetrical mode A is equal to 34. Only the rays which fall on the tube at this angle of incidence will be capable of generating Lamb waves within this tube; flaws can be detected by this means since said waves are propagated differently according to whether flaws are either present or absent in the tube.
  • the flaw is detected by measuring the time interval which elapses between the emission of a wave train and the return of the reflected wave through the flaw or alternatively by placing a second transducer-receiver for receiving the waves which are reflected or diffracted by the flaw.
  • the number of periods of Lamb waves in phase with the longitudinal waves of the incident beam must be at least equal to 4 or 5 in order to ensure that the Lamb waves within the tube are sufficiently strongly excited.
  • the angle of divergence of the beam within which the angle of incidence is very close to the angle corresponding to the generation of the Lamb waves of the mode selected must therefore be as large as possible.
  • the first transducers employed for the detection of longitudinal flaws in tubes were flat.
  • the mean ray emitted by the center of the transducer impinges on the cylinder at an angle 0 but the two end rays derived from the edges of the transducer make different angles with the normal to the cylinder at the point of impact as will be indicated more precisely in FIG. 2 which will be described below.
  • the arc of circumference on which the waves are in phase is very small and the Lamb waves are weakly excited.
  • the detection along a helix is particularly useful when tubes are welded along a plane which is inclined with respect to the generating-lines of the cylinders constituting said tubes; in this case, the angle of the helix with respect to the generating-lines is chosen so as to be complemen tary to the angle made by the inclined plane with the same generating-lines.
  • the precise aim of the present invention is to provide a deflector which is primarily intended to excite Lamb waves at the surface of a cylindrical part C, the cross section of said part being either a polygonal or circular directrix.
  • the deflector converts a beam F of rays which are parallel to the generating-lines of the cylindrical part C having a polygonal directrix into a beam F of rays which impinges upon the surface of said part in a family of broken helices which are parallel to each other, each helix being constituted by a plurality of straight-line segments which are concurrent in pairs along one edge of the cylindrical part C.
  • the rays of the beam F make a constant angle of incidence i with respect to the normal to the surface of the part at the point at which each ray of the beam F strikes said surface.
  • Each segment of the helix is inclined at an angle ,8 with respect to a plane at right angles to the generating-lines of said cylindrical part.
  • said angle [3 is constant from one face to the other in the deflector in accordance with the invention. However, by making minor changes, it would be possible to vary said angle from one face to the other although the technical advantage of this is not at present apparent. Since the angle [3 is chosen so as to have a fixed value, the broken helix formed by the plurality of segments aforementioned is a helix having a constant pitch Each flat deflecting element M, is associated with one face P, of said part C.
  • each flat deflecting element M is defined by the direction of the normal r7, having projections which are proportional in three perpendicular directions and which are a generating-line of the part C, a normal to the face P, and an axis at right angles to the two preceding projections respectively at cos a, cos j sin a, and sin j sin a.
  • the rotation takes place about an axis parallel to the generating lines of the part C and located in a plane which is equidistant from the edges A, and A the angle of said movement of rotation is equal to the angle of the dihedron constituted by the faces P, and P and there is added to this movement of rotation a movement of translation which is parallel to the generating-lines by a quantity a sin j tan where a is the width of the face P,.
  • the result thereby achieved is that rays which arrive on the edge A, which is common to the two faces P, and P and are derived from two consecutive deflectors are of equal phase.
  • the deflector in accordance with the invention is such that the deflected rays of the beam F are incident upon the cylindrical part C in a direction at right angles to the generating-lines and make a constant angle i with the normal to the face of the part C.
  • the families of broken helices are reduced to a family of parallel polygonal directrices located in an equatorial plane at right angles to the generating-lines.
  • the deflector is constituted by a plurality of flats deflecting elements, each of these deflectors M, being associated with one face P, of said part, the section of each deflecting element M, aforesaid through a plane at right angles to the generating-lines of the part C being a segment of straight line 8,.
  • the deflecting elements M are disposed in such a manner as to ensure that each segment S, makes the same angle i with the associated face P,; moreover, two of these segments S, and S, which form part of two consecutive deflectors M, and M, are equidistant from the edge A, located at the intersection of the two faces P, and P
  • the deflector is constituted by a plurality of flat deflecting elements M,, each deflecting element M, which is associated with the face P, being such as to make an angle with the associated face P,
  • the deflector is constituted by a continuous surface whic h can be considered as the limiting surface of the different planes of the deflecting elements considered earlier; this limit is obtained when all the sides of the polygon constituting the directrix are ,the number of said deflecting elements tends towards infinity.
  • This transition to the limit shows that the surface S is ruled and developable, which is an advantage since it can readily be formed by milling.
  • the axis 02 coincides with the axis of the cylindrical part.
  • the angle B defined earlier is zero and the helices are replaced by directorcircles.
  • the surface of the deflector then corresponds to the'equation expressed in polar coordinates havin anaxis Oz To insure a constant illumination of all the generating-lines of the cylinder the intersection of the surface of the deflector along the planes at right angles to the generating lines are are of involutes (of circles) of constant length.
  • the transducer and the deflector can be placed inside or outside the cylinder.
  • the transducer is in that case an annular transducer which is coaxial with the cylinder.
  • FIG. 1 shows a flat transducer which directs a beam 'onto a surface at an angle corresponding to the excitation of Lamb waves
  • FIG; 2 shows the variation of the angle of incidence in the case of a flat transducer which directs a beam of parallel rays onto a circle;
  • FIG. 3 shows the variation in the angle of inclination of the rays which impinge on a circle, said rays being focused by a disc or a lenshaving a circular directrix;
  • FIG. 4 shows the geometrical parameters which are related to the travel of the incident rays along a broken helix on a prismatic cylindrical part, these geometrical parameters being such as to define the positions of the flat deflecting elements;
  • FIG. 5a and 5b show a deflector which is composed of a plurality of flat deflecting elements and intended to deflect a beam F of rays parallel to the generating-lines of a right cylinder having a base in the shape of a regular hexagon so as to form a beam F of rays having a constant incidence on a transverse section;
  • FIG. 6 shows a deflector which is composed of six flat deflecting elements and is intended to deflect a beam F of rays parallel to the generating-lines of a right cylinder having a base in the form of a regular hexagon in a beam F of rays having a constant incidence on a generating-line of said cylinder;
  • FIG. 7 shows the geometrical parameters which are related to the travel of incident rays along a continuous helix on a cylindrical part having a circular directrix, these parameters being intended to define the geometrical nature of the surface constituting the deflector;
  • FIG. 8 shows an outline of a deflector in the form of a helix for deflecting a beam F of rays parallel to the generating-lines of a cylinder having a circular directrix in a beam F of rays located in an equatorial plane and having a constant incidence on a directrix of the cylinder;
  • FIG. 9 shows an assembly consisting of a deflector in the form of a helix, a transducer and a cylinder in the case in which the transducer and deflector are located inside the cylinder;
  • FIG. 10 is a perspective view of a helical deflector obtained by milling in the mass.
  • FIG. 1 the diagram of a known device for inducing Lamb waves on a plate 2.
  • the transducer 4 of diameter a has an angle of inclination 6 with respect to the plane constituted by the top face of the plate 2.
  • Said transducer emits a beam of parallel rays in which the wavelength is equal to M.
  • the rays of the beam of waves make an angle 6 with the normal to the surface of the plate 2.
  • the Lamb waves in phase with the incident waves having wavelengths A are such that M M/sin 6; a Lamb wave is shown at 6.
  • the Lamb waves are excited in phase over a length equal to a/cos 6.
  • FIG. 2 There is shown in FIG. 2 a transducer 4 for emitting a beam of parallel rays received by a thin tube in which the cross-section of the external surface has the shape of a circle C having a radius R and a center 0. It is ap- Lamb waves within the cylinder: in other words, the coupling between the transducer and the medium constituted by the tube of section C is poor.
  • FIG. 3 a device for focusing waves on a cylinder having a circular section C with a view to reducing the variations in angle of inclination of the incident rays with respect to the external wall of said cylinder.
  • Said focusing device comprises a cylindrical disc or lens of circular section, the focal line of which passes through the point N and is parallel to the axis of the cylinder whose section is the circle C.
  • the angle a is the semivertical angle of the beam which is convergent on the point N.
  • the rays coming from the extremities of the disc or lens L intersect the circle C at A and B.
  • the points A, B, N and O are located on a circle.
  • the focal point N of the beam is located on the circle defined by the center of the tube and the end points of impact A and B, the angles of incidence at A and B are equal to 6 e.
  • the incidence is not constant in this known system.
  • the arc AB is of greater length in order to increase the length of excitation of the Lamb waves on the wall of the cylinder (second condition), so the variation in the angle of incidence is greater and this is contrary to the essential requirements of the first condition of excitation of Lamb waves.
  • FIG. 4 A cylindrical face C of the part contains the axes Ox and Oz, Oz being on the edge A of the face P,.
  • This face P is a surface of the cylindrical prismatic part C having a polygonal directrix.
  • the plane xOy is perpendicular to the generating-lines of the part C and to the edges such as Oz. It is desired to excite waves in a family of broken helices having an angle of inclination B with respect to the plane at right angles to the generating-lines, that is to say the plane xOy; said helices are constituted by a plurality of contiguous segments, a single segment TV being shown in this figure.
  • the beam F of parallel rays emitted by a transducer is a beam F of rays which are parallel to the generating-lines of the part C.
  • the ray PM is one of these rays.
  • the point M is the point of the deflector at which the ray PM is reflected along the line MA. Tiis the normal to the surface of the deflector at the point M, the angles a being the angles of incidence and of reflection on said deflector.
  • the ray MA makes a constant angle i with the normal ii to the face P at the point A located along the segment TV.
  • the point N is the projection of the point M on the plane xOy; similarly, the point B is the projection of the point A on the same plane.
  • the segment KMJ represents the intersection along a horizontal plane parallel to the plane xOy which passes through the point M of the deflector M, which is associated with the face P.
  • This intersection KM] is projected along KNJ' on the plane xOy.
  • the point E is the projection of the point A on the segment MN;
  • the point C is the projection of the point M on the normal 77 to the surface of the cylinder at the point A.
  • the flat surface of the deflector M could have been characterized by another of its sections, namely the section WMZ of the deflector in the plane of incidence of the rays on the deflector, that is to say the plane defined by the straight line PM and the normal fito the deflector. It is readily apparent that the angle of said section WMZ in the plane of incidence as defined makes an angle (17/2 a) with the axis Oz, that is to say with the direction of the generating-lines of the cylindrical part.
  • the inclination of the plane of the deflecting element being determined, the position of said element is also determined by satisfying the condition which ensures that the incident rays from two consecutive deflectors on one point of an edge such as Oz are in phase.
  • the mirror M is deduced from the mirror M; by a rotation about an axis parallel to the generating-lines through an angle equal to that of the dihedron constituted by the faces P, and P followed by a movement of translation of the vector which is parallel to Oz and has a value OT sin j tan a.
  • the axis of rotation which causes the edge A, to coincide with the edge A is contained in the plane which is equidistant from the edges A and A
  • FIGS. 5a and Sb there is shown a deflector associated with a cylindrical prismatic part C having a regular hexagon directrix.
  • FIG. 5a and 5b correspond to the particular case in which the rays such as 24 deflected by the deflector are in a plane at right angles to the generating-lines of the cylindrical part C.
  • FIG. 5b shows the deflector and the cylindrical part C which is displaced in the vertical direction for reasons of clarity of the drawing.
  • the deflector comprises a plurality of deflecting elements D D D D D D and D Consideration is given to the rays of the beam F which fall on the portions of the deflector C B B A A F and which are reflected from the surface of said deflectors in an equatorial plane in a beam F.
  • the rays such as the ray 26 of the beam F which are contained in an equatorial plane make an angle i with the associated face of the cylindrical part as shown in the figure. It can be verified that the segment A 3 which is a section of the transducer D in an equatorial plane of the cylinder makes an angle i with the face of the associated cylindrical part C, said angle i being represented by the angle between the extensions of the segments A 8 and A B The deflecting elements D D etc.
  • the lengths B B, and B B are equal, with the result that the waves are excited in phase at the point B by the two deflectors D and D
  • This phenomenon is general: the difference in path between two incident rays at any two points on the surface of the part C corresponds exactly to the difference in phase of the wave induced in the material between the two points at which the rays meet the tube.
  • the waves are in fact excited in phase by all the rays which come from the transducer and are deflected by the deflecting elements.
  • the waves which are excited at any point of the object have the same value of excitation.
  • the waves which are excited at F result from the cumulative effect of the incident rays on the segments C B B A A F
  • the rays which are directed to these three segments come from the rays of the beam F which are deflected by the segments of the deflectors C 8 B A and A F-
  • the level of excitation of the Lamb wave at the point F 0 will thus be proportional to the cumulated length of the segments C 8 B A and A F namely
  • the deflector is chosen so as to ensure that the cumulated length of the intersections of the deflecting elements in all the planes at right angles to the generatinglines of the different elements of the deflector is constant.
  • the level of excitation at any point of the directrix A B C D E F corresponds to excitations produced by segments of deflectors having a constant cumulated length, with the result that said excitation level is constant.
  • the angle i has a value of 30 and the deflector is employed for observing longitudinal flaws, that is to say flaws which are parallel to the axis of the part C.
  • the transducer T is shown in chain-dotted lines at the top of FIG. 5b and is intended to deliver a beam of rays F.
  • the intersections of the deflecting elements D D and so forth in an equatorial plane are relatively displaced so as to ensure that the paths between a given edge and the two facets which illuminate said edge are equal for the continuity of phases from one face to the other.
  • the pitch of the pseudohelix constituted by the different deflectors D D D D D D is equal to 6 a sin i, in which, as indicated in FIG. 5a, a is the width of one of the sides of the hexagon constituting a section of the part C in an equatorial plane. It can be established that any two consecutive deflecting elements such as D, and D for example .are deduced from each other by a movement of rota tion through an angle of 60 about the axis of the hexagonal cylinder which passes through 0, followed by a movement of translation parallel to the generating-lines of the value a sin i. All the deflecting elements will thus have been obtained, that is to say the pitch of the helix 10 considered, after a movement of translation of 6a sin 1' which is the pitch of the helix.
  • the transducer T and the deflector are usually stationary and that the part C can be observed continuously by displacing said part in translational motion along its axis within the stationary transducer-deflector unit. It is thus possible to observe the entire surface of a tube of prismatic section, the transducer T being intended to perform the function of an emitter-receiver while displacing said part in translational motion.
  • FIG. 6 shows a deflector in accordance with the invention for observing transverse flaws in a cylindrical part C having a section in the shape of a regular hexagon.
  • the beam of rays F emitted by the transducer T is reflected from the elements of the deflector such as the elements P and P and impinges on the surface of the part C at a constant angle of incidence 1, namely 30 in the case of the figure.
  • the rays of the beam F are in phase along the same generating-line of the part C.
  • All the generating-lines of the part C are subjected to the same intensity of radiation since the length of the segments A"B" is constant irrespective of the section of the elements of the deflector in planes parallel to the generating-lines of the part C and at right angles to the faces.
  • the deflector which has just been considered serves to observe transverse flaws in a part having a section in the shape of a regular hexagon. As in FIG. 5, it can be established that all the points of the generating-lines are excited with the same amplitude, the illumination of the generating-lines being constant at each point.
  • the deflectors form a frustum of a regular pyramid having six sides. Each side makes an angle with the associated face of the prismatic part C of hexagonal section.
  • the sign 1- in the expression which defines the angle depends on whether it is desired to cause the beam of rays F to impinge on the deflector at an acute or obtuse angle 2a; the rays of the beam F travel upwards with respect to the horizontal in the case of an acute angle 201- as shown in the figure whereas said rays travel downwards with respect to the horizontal in the case of an obtuse angle 20:.
  • FIG. 7 shows the geometrical parameters which are related to the path of the incident rays along a circular and continuous helix H on a cylindrical part C having a circular directrix.
  • the geometrical parameters such as i the angles i, j, at and B define the geometrical nature of the surface which constitutes the deflector.
  • the ray PM which is parallel to the axis Oz of the cylinder constituting the part C is incident at M on the surface of the deflector and is reflected along the segment MA which makes an angle of incidence iwith the normal N to the cylinder C at A.
  • the point M is projected along a vertical line parallel to the generating-lines at N on the plane xOy and it can be verified that the projection of the normal Won the plane xOy constituted by the segment NB makes a constant angle j with the normal to it it the circular directrix of radius R of the cylinder C.
  • the projections of the normals to the surface of the deflector such as fion a plane at right angles to said generating-lines enclose a circle having a radius R sin j (the circle which passes through F in FIG. 7).
  • the rays are incident on the helix H which passes through the point A and is represented by a line of double thickness.
  • the tangent to said helix at any point A makes an angle B with the plane at right angles to the generating-lines, that is to say the plane xOy.
  • the properties of the projections to the normal ii'to the deflector on the plane xOy which enclose the circle having a radius R sinj are such that the section of the surface of the deflector along said plane is an involute of the circle having a radius R sin j, j, being related to the angles i and B by the relation tan j tan i cos [3.
  • FIG. 8 shows the deflector M having an equation defined by means of its rectilinear generating-lines in the case in which said deflector M surrrounds the cylinder 40 of radius R.
  • the surface of the deflector M is a ruled surface.
  • a first rectilinear generating-line 52 extends from the point A located on the circle 54 having a radius R sin j. Said generating-line is located in the plane 56 tangent to the cylinder in which the cross-section at the base of said cylinder is the circle 54.
  • the generating-line 52 makes an angle a (in this case of figure a 1r/4 with a plane at right angles to the axis Oz.
  • a second generating-line such as the line 58 corresponding to a movement of rotation of 77/2 starts from a point B located on a generating-line of the cylinder having a radius R sin j at a distance from the plane containing the point A which is equal to 1rRsinjtanrx
  • This generating-line is contained in a plane tangent to the cylinder of radius R sin j and of axis Oz and makes an angle a with a plane at right angles to the axis Oz.
  • the generating-lines 60, 62 and 64 are obtained in the same manner.
  • the generating-line 64 is obtained from the point C located on the cylinder of radius R sin j, the segment AC being parallel to the axis Oz and having a length 27rR sinjtan oz. Said generating-line 64 is parallel to the generating-line 52.
  • FIG. 9 shows the deflector M and a transducer 66 in the case in which said deflector M and the transducer are placed inside the cylinder 68 of internal radius R.
  • the rays emitted by the transducer in a direction parallel to the axis Oz are reflected by the mirror M and strike the internal surface of the cylindrical tube 68 at a constant angle of incidence equal to i. Said rays are shown at 72, 74 and 76.
  • FIG. is a view in perspective showing the deflector M of FIG. 8 in the case in which said deflector is milled in the solid.
  • the surface corresponding to the deflector M is represented at 200 and the cylindrical tube 201 to be inspected passes within the interior of the mirror. It is readily apparent that a sufficient space is left between the tube 201 to be inspected and the deflector 200 in order to ensure that the tube is capable of sliding freely inside the deflector.
  • the assemblies consisting of flat transducers and deflectors in accordance with the invention permit detection of longitudinal flaws in cylindrical parts with a much higher degree of sensitivity by means of longduration phasing of the Lamb waves with the rays of constant incidence.
  • the deflector M also makes it possible to perform this phasing operation over a length which is independent of the generating-line on which the flaw is located. The relative movement of rotation of the part with respect to the transducer therefore no longer serves any useful purpose for the inspection of the entire part.
  • the deflector M can be chosen as a function of the angle of inclination -y of flaws with re spect to the axis of the tube and the value 5 y will accordingly be adopted.
  • the transducers in accordance with the invention as well as the mirrors and lenses described have a useful function in exciting waves to a predetermined depth from the surface of the body to be tested.
  • the waves which are excited within the medium exist only within the space formed between the external surface and the enclosed surface of the rays which are generated by refraction.
  • the enclosed surface is parallel to the external surface.
  • a deflector for converting a beam F of rays parallel to the generating-lines of a cylindrical part C having a polygonal directrix into a beam F of rays impinging upon the surface of said part at a constant angle of incidence i so as to generate therein refracted waves in which the sections of the associated wave surfaces along the surface of said part are at right angles to a family of broken helices, each helix being constituted by a plurality of straight-line segments which are concurrent in pairs along the edges of the cylindrical part C, each segment being inclined at an angle [3 with respect to a plane at right angles to the generating-lines of said cylindrical part C, wherein said deflector is constituted by a plurality of flat deflecting elements, at least one deflecting element M, being associated with each face P; of said part, the orientation of each flat deflecting element M, being defined by the direction of its normal n,- whose projections are proportional to cos a on a generating-line of the part
  • a deflector according to claim 1 for converting a beam F of rays parallel to the generating-lines of a cylindrical part C having a polygonal directrix into a beam F of rays impinging upon the lateral surface of said part at a constant angle of incidence i and such that B with the result that the families of broken helices are reduced to the family of parallel directrices located in equatorial planes at right angles to the generating-lines, wherein said deflector is constituted by a plurality of flat deflecting elements, at least one deflecting element M, being associated with each face P, of said part, the section of each deflecting element M, aforesaid along a plane at right angles to the generating-lines of the part C being a straight-line segment S, which makes an angle of the same value 1' with the associated face P, and wherein two of said segments S, and S, forming part of two consecutive deflecting elements M, and M, are equidistant from the edge A, which is
  • a deflector according to claim 1 for converting a beam F of rays parallel to the axis of a cylindrical part C having a polygonal directrix into a beam F of rays impinging upon the surface of the part C at a constant angle of incidence i and such that B 1r/2, with the result that the families of broken helices are reduced to segments of generating-lines, wherein said deflector is constituted by a plurality of flat deflecting elements M, forming a pyramidal surface, each deflecting element M, associated with the face P, being such as to make an angle 14 with the associated face P,
  • a deflector according to claim 2 wherein the eumulated length of the segments S, is constant in each plane at right angles to the generating-lines.
  • a deflector according to claim 5 for converting a beam F of rays parallel to the generating-lines of a cylindrical part C having an axis Oz and a circular directrix of radius R into a beam F of rays impinging upon the lateral surface of said part C at a constant angle of incidence i along a family of circles which are transverse cross-sections of the cylindrical part, wherein the surface of the 'deflector is a portion of the surface which has the equation expressed in polar coordinates of axis 02:
  • Z VP2R2 sin i+R sinif) 7.

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  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US535703A 1973-12-26 1974-12-23 Deflector for converting a beam of parallel rays into a beam of rays having constant incidence on cylindrical part Expired - Lifetime US3916675A (en)

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FR7346384A FR2256617B1 (sv) 1973-12-26 1973-12-26

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US (1) US3916675A (sv)
JP (1) JPS5843693B2 (sv)
BE (1) BE823664A (sv)
CA (1) CA1009359A (sv)
DE (1) DE2461590C2 (sv)
FR (1) FR2256617B1 (sv)
GB (1) GB1495536A (sv)
IT (1) IT1027183B (sv)
LU (1) LU71543A1 (sv)
NL (1) NL7416832A (sv)
PL (1) PL104062B1 (sv)
SE (2) SE404845B (sv)
SU (2) SU740163A3 (sv)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4102206A (en) * 1976-07-21 1978-07-25 Commissariat A L'energie Atomique Device for inspecting a tube by ultrasonics
US4151752A (en) * 1976-01-06 1979-05-01 Commissariat A L'energie Atomique Device for the excitation of waves and especially ultrasonic waves including a cell
US4195530A (en) * 1978-08-14 1980-04-01 Republic Steel Corporation Ultrasonic inspection
WO1981002636A1 (en) * 1980-03-03 1981-09-17 Republic Steel Corp Ultrasonic inspection
USRE30926E (en) * 1978-08-14 1982-05-11 Republic Steel Corporation Ultrasonic inspection
US4453410A (en) * 1980-01-31 1984-06-12 Ruhrchemie Aktiengesellschaft Method and apparatus for locating material defects in hollow bodies
DE4421847A1 (de) * 1994-06-23 1996-01-04 Fraunhofer Ges Forschung Vorrichtung zum Messen von Unregelmäßigkeiten in Behälterinnenwänden mit Ultraschall
US20030225346A1 (en) * 2002-06-04 2003-12-04 Moshe Ein-Gal Wave generating device
CN112702669A (zh) * 2020-12-21 2021-04-23 西安讯飞超脑信息科技有限公司 拾音设备、方法、装置、系统和存储介质

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6026637U (ja) * 1983-07-29 1985-02-22 アルパイン株式会社 テ−プレコ−ダ
JPS6040022U (ja) * 1983-08-20 1985-03-20 日本ビクター株式会社 ダビング装置
JPS6044220U (ja) * 1983-08-31 1985-03-28 三洋電機株式会社 テ−プレコ−ダ−の制御回路
JPS6070922U (ja) * 1983-10-19 1985-05-20 シャープ株式会社 磁気記録再生機におけるダビング装置
JPS60124030A (ja) * 1983-12-08 1985-07-02 Pioneer Electronic Corp ダブルデツキ
US4836329A (en) * 1987-07-21 1989-06-06 Hughes Aircraft Company Loudspeaker system with wide dispersion baffle
US5784468A (en) * 1996-10-07 1998-07-21 Srs Labs, Inc. Spatial enhancement speaker systems and methods for spatially enhanced sound reproduction
DE10034474C1 (de) * 2000-07-15 2001-10-11 Flexim Flexible Industriemeste Verfahren und Vorrichtung zur Charakterisierung eines Fluides oder Gases mittels Ultraschall
DE20116591U1 (de) 2001-10-10 2002-01-24 Siemens AG, 80333 München Einrichtung zur Erfassung der Position einer Leiterplatte
CN110441390B (zh) * 2019-07-18 2021-12-07 上海大学 一种基于十字阵和空间-波数滤波器的损伤定位方法
EP4086620A1 (en) * 2021-05-05 2022-11-09 NDT Global Corporate Ltd. Ireland Method and device for checking the wall of a pipeline for flaws

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU201752A1 (ru) * В. С. Загорулько Ультразвуковой пластинчатый излучатель
SU142467A1 (ru) * 1961-01-16 1961-11-30 Я.Ф. Аникеев Ультразвуковой иммерсионный дефектоскоп
CH468009A (de) * 1963-09-10 1969-01-31 Kredit Und Anlage Ag Vorrichtung zur Ultraschall-Materialprüfung von Körpern mit gekrümmter Oberfläche

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU201752A1 (ru) * В. С. Загорулько Ультразвуковой пластинчатый излучатель
SU142467A1 (ru) * 1961-01-16 1961-11-30 Я.Ф. Аникеев Ультразвуковой иммерсионный дефектоскоп
CH468009A (de) * 1963-09-10 1969-01-31 Kredit Und Anlage Ag Vorrichtung zur Ultraschall-Materialprüfung von Körpern mit gekrümmter Oberfläche

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4151752A (en) * 1976-01-06 1979-05-01 Commissariat A L'energie Atomique Device for the excitation of waves and especially ultrasonic waves including a cell
US4102206A (en) * 1976-07-21 1978-07-25 Commissariat A L'energie Atomique Device for inspecting a tube by ultrasonics
US4195530A (en) * 1978-08-14 1980-04-01 Republic Steel Corporation Ultrasonic inspection
USRE30926E (en) * 1978-08-14 1982-05-11 Republic Steel Corporation Ultrasonic inspection
US4453410A (en) * 1980-01-31 1984-06-12 Ruhrchemie Aktiengesellschaft Method and apparatus for locating material defects in hollow bodies
WO1981002636A1 (en) * 1980-03-03 1981-09-17 Republic Steel Corp Ultrasonic inspection
DE3050285C2 (de) * 1980-03-03 1987-03-12 Republic Steel Corp., Cleveland, Ohio Vorrichtung zur Ultraschall-Materialpr}fung eines zylindrischen Gegenstandes
DE4421847A1 (de) * 1994-06-23 1996-01-04 Fraunhofer Ges Forschung Vorrichtung zum Messen von Unregelmäßigkeiten in Behälterinnenwänden mit Ultraschall
US20030225346A1 (en) * 2002-06-04 2003-12-04 Moshe Ein-Gal Wave generating device
US7410464B2 (en) * 2002-06-04 2008-08-12 Moshe Ein-Gal Wave generating device
CN112702669A (zh) * 2020-12-21 2021-04-23 西安讯飞超脑信息科技有限公司 拾音设备、方法、装置、系统和存储介质

Also Published As

Publication number Publication date
SU740163A3 (ru) 1980-06-05
DE2461590C2 (de) 1986-08-21
LU71543A1 (sv) 1975-06-17
IT1027183B (it) 1978-11-20
GB1495536A (en) 1977-12-21
SE7416268L (sv) 1975-06-27
DE2461590A1 (de) 1975-07-10
CA1009359A (en) 1977-04-26
SE404845B (sv) 1978-10-30
BE823664A (fr) 1975-04-16
FR2256617B1 (sv) 1980-03-21
SE7807113L (sv) 1978-06-21
PL104062B1 (pl) 1979-07-31
JPS51135589A (en) 1976-11-24
JPS5843693B2 (ja) 1983-09-28
FR2256617A1 (sv) 1975-07-25
SU660606A3 (ru) 1979-04-30
NL7416832A (nl) 1975-06-30

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