JPWO2015190414A1 - Nondestructive inspection equipment - Google Patents

Abstract

An object of the present invention is to provide a nondestructive inspection apparatus that can be easily installed regardless of the shape of an object to be inspected in a nondestructive inspection using a pulsed magnetic field. A nondestructive inspection apparatus 10 using a magnetic field response to a pulsed magnetic field includes a U-shaped yoke 12a and excitation coils 12b and 12c wound around the yoke 12a.

Description

  The present invention relates to a nondestructive inspection apparatus using a magnetic field response to a pulsed magnetic field.

  In recent years, aging factory and infrastructure has become a problem in the industrial field. For example, in pipes covered with a heat insulating material and a surface metal plate, so-called heat insulating pipes, it is a problem that corrosion occurs on the steel pipe surface under the heat insulating material. It is difficult to inspect this problem without removing the sheet metal and the heat insulating material, which is a big problem.

  Therefore, a technique for inspecting the deterioration state of pipes and steel materials in a non-destructive manner is attracting attention. In such a non-destructive inspection, it is desirable that the inspection is simple and highly robust and can be inspected in a short time in order to efficiently inspect a wide area such as an infrastructure. In particular, non-destructive inspection based on the detection principle based on the magnetic response generated by applying an external magnetic field to the object to be inspected has the excellent feature that non-contact inspection is possible. It is expected as a method.

  For example, Patent Document 1 discloses a technique for inspecting a pipe for defects by inserting a pipe through an exciting coil, applying a pulsed magnetic field to an object to be inspected, and measuring the magnetic field response. By using a pulsed magnetic field, the signal frequency is widened, making it possible to detect defects deeper than conventional high-frequency eddy current flaw detection methods, thereby capturing the presence or absence of defects under insulation. It is possible.

JP 2014-44087 A

  In Patent Document 1, the exciting coil can be separated by a coil connection connector. However, when the number of windings of the exciting coil increases, the rigidity of the exciting coil increases and it becomes difficult to attach to the piping to be inspected. Moreover, it is necessary to prepare an exciting coil according to the shape of the piping to be inspected, and there is no versatility.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a nondestructive inspection apparatus that can be easily installed regardless of the shape of an object to be inspected in a nondestructive inspection using a pulsed magnetic field.

  An apparatus according to one aspect of the present invention is a nondestructive inspection apparatus using a magnetic field response to a pulsed magnetic field, and includes a U-shaped yoke and an excitation coil wound around the yoke.

It is the schematic which shows the nondestructive inspection apparatus of one Embodiment of this invention. It is the schematic which shows the nondestructive inspection apparatus of one Embodiment of this invention. It is the schematic which shows the nondestructive inspection apparatus of one Embodiment of this invention. It is the schematic which shows the nondestructive inspection apparatus of one Embodiment of this invention. It is a figure explaining the mode of the test | inspection using the nondestructive inspection apparatus of FIG. It is a block diagram which shows the main structures of the nondestructive inspection apparatus of one Embodiment of this invention. It is the schematic which shows the nondestructive inspection apparatus of one Embodiment of this invention. It is a top view of the plug and jack vicinity of FIG. It is a top view of the state which connected the plug and jack of adjacent nondestructive inspection apparatuses. It is a figure explaining the mode of the test | inspection using the nondestructive inspection apparatus of FIG. It is a figure explaining the mode of the test | inspection using the nondestructive inspection apparatus of FIG. It is a figure explaining the mode of the test | inspection using the nondestructive inspection apparatus of FIG. It is a figure which shows an example of the nondestructive inspection apparatus connected in series. It is a figure which shows an example of the nondestructive inspection apparatus connected in parallel.

  Hereinafter, an embodiment of a nondestructive inspection apparatus using a magnetic field response to a pulsed magnetic field will be described. 1 to 4 are schematic views showing a nondestructive inspection apparatus according to an embodiment of the present invention, FIG. 5 is a diagram for explaining an inspection using the nondestructive inspection apparatus of FIG. 1, and FIG. It is a block diagram which shows the main structures of the nondestructive inspection apparatus of embodiment.

  First, an object to be inspected used in the present embodiment will be described with reference to FIG. As shown in FIG. 5, a heat insulating pipe 50 is used as an example of an object to be inspected. The heat insulating pipe 50 is a main body of the pipe, which is a steel pipe 51 made of carbon steel or the like, a heat insulating material 52 made of calcium silicate covering the outer surface of the steel pipe 51, a galvanized steel plate or carbon steel covering the outer surface of the heat insulating material 52, etc. It is comprised with the surface sheet metal 53 which consists of. The heat insulating material 52 is packed between the steel pipe 51 and the surface sheet metal 53 without a gap.

For example, the steel pipe 51 can be made of carbon steel (relative magnetic permeability is 150, electric resistivity is 15 × 10 ⁻⁸ Ωm), the inner diameter is 150 mm, and the wall thickness is 7.1 mm. As the heat insulating material 52, calcium silicate (non-conductor having a relative permeability of 1) can be used. The surface sheet metal 53 can be made of the same material as the steel pipe 51 and has an inner diameter of 265 mm and a wall thickness of 0.3 mm.

  In addition, as a to-be-inspected object, piping etc. containing not only such a steel pipe 51 but the material (for example, conductor) whose relative permeability is not 1 can be used. In addition, the test object may be a pipe made of only a steel pipe, and is not limited to a pipe, and various shapes such as a test object having a large area close to a plane such as a steel plate can be used. .

  As shown in FIG. 1 or FIG. 6, the nondestructive inspection apparatus 10 includes a pulse current source 11, a pulse magnetic field generation unit 12, a magnetic detection unit 13, a moving unit 14, and a control unit 15.

  The pulse current source 11 supplies a predetermined pulse current to the pulse magnetic field generation unit 12 according to an instruction from the control unit 15. The pulse magnetic field generator 12 is connected to the pulse current source 11 and generates a pulse magnetic field to be applied to the object to be inspected (the heat insulating pipe 50) by the current from the pulse current source 11.

  The pulse magnetic field generator 12 is a unit that includes a yoke 12a and exciting coils 12b and 12c. The yoke 12a is composed of a long side portion extending substantially linearly and two short side portions each extending in the same direction so as to be substantially perpendicular to the long side portion from both ends of the long side portion. It has a letter shape. The two short sides are both ends (including the vicinity of both ends) of the yoke 12a. Here, the U-shape refers to all shapes in which a part of the ring is open, and may be a curved shape without corners or a polygonal shape with corners. The tip surfaces 12d and 12e at both ends of the yoke 12a are substantially parallel, and more preferably on the same plane. The yoke 12a is preferably made of a material having high magnetic permeability such as a silicon steel plate or ferrite. When inspecting the heat insulation pipe 50, the tip surfaces 12d and 12e at both ends of the yoke 12a are brought into contact with the heat insulation pipe 50 as shown in FIG.

  If the object to be inspected is sufficiently large with respect to the yoke 12a, the yoke 12a can be inspected in addition to being installed so that the longitudinal direction of the yoke 12a and the axial direction of the heat insulating pipe 50 are parallel as shown in FIG. Inspection is possible no matter which direction 12a is installed.

  The exciting coils 12b and 12c are wound around both end portions (short side portions) of the yoke 12a. The exciting coils 12b and 12c are connected to the pulse current source 11 so that currents flow in opposite directions, and an arbitrary pulse current is supplied to form a magnetic field as shown by an arrow in FIG. That is, the magnetic flux generated in one exciting coil 12b enters the heat insulating pipe 50 from the radial direction, proceeds in the heat insulating pipe 50 along the axial direction (longitudinal direction), and the other excitation is performed from the radial direction of the heat insulating pipe 50. It goes to the coil 12b. In other words, one end of the yoke 12a is an N pole and the other end is an S pole, and a magnetic flux is given in a direction perpendicular to the surface of the heat insulating pipe 50, and a magnetic flux from the N pole toward the S pole is axially passed through the heat insulating pipe 50. It flows in (longitudinal direction).

  The magnetic detection unit 13 includes a magnetic sensor 13a and a detection circuit 13b, detects a magnetic field response to a pulsed magnetic field, and generates a magnetic field response signal. Magnetic flux density can be used as the intensity of the magnetic field response. The magnetic sensor 13a is provided in the vicinity of the center of the long side portion of the yoke 12a and in the U-shaped inner portion in the same direction as the extending direction of the short side portion. The magnetic sensor 13a is preferably provided at a position that protrudes from the yoke 12a and has the same length as the short side or a slightly shorter length. By bringing the magnetic sensor 13a as close as possible to the object to be inspected, the SN ratio at the time of detecting the magnetic field response signal is improved, and more accurate detection becomes possible.

  The magnetic sensor 13a measures the magnitude and direction of a magnetic field (magnetic field). In this embodiment, various sensors that can detect a magnetic field response to a pulsed magnetic field can be used. For example, a coil, an MR (Magneto Resistance) element, a Hall element, a magneto-impedance element, a SQUID (Superconducting Quantum Interference Device), or the like can be used. As the MR element, an AMR (Anisotropic Magneto Resistance) element, a TMR (Tunnel Magneto Resistance) element, or the like can be used. The magnetic sensor 13a may be provided at a position other than the yoke 12a or a position other than the yoke 12a as long as the response magnetic field can be detected.

  The detection circuit 13b is connected to the magnetic sensor 13a, and receives an input from the magnetic sensor 13a to generate a magnetic field response signal. The detection circuit 12 b is connected to the control unit 15 and outputs the generated magnetic field response signal to the control unit 15.

  The moving unit 14 has a self-propelled mechanism for moving the yoke 12a and the magnetic sensor 13a along the object to be inspected. For example, by driving a wheel provided in the nondestructive inspection apparatus 10 with a motor, nondestructive inspection is performed. The device 10 can freely move on the heat insulating pipe 50. The control unit 15 obtains a magnetic field response signal at high speed while moving the yoke 12a and the magnetic sensor 13a by controlling the pulsed magnetic field to be applied while driving the moving unit 14 (for example, every 20 to 30 mm). Can be efficiently inspected over a wide area. The moving unit 14 may be configured to move manually without a power source such as a motor.

  The control unit 15 controls the pulse current source 11, the magnetic detection unit 13, and the moving unit 14, that is, controls the entire nondestructive inspection apparatus 10. The control unit 15 determines a flaw in the steel pipe 51 based on the magnetic field response signal acquired from the detection circuit 13b. For example, the attenuation waveform of the magnetic field response signal is normalized, the attenuation time of the normalized waveform is calculated, and the flaw of the steel pipe 51 can be analyzed. Scratches are based on the thickness of the steel pipe 51, and the decay time becomes shorter as the thickness becomes thinner due to corrosion or the like.

  With reference to FIGS. 2-4, the nondestructive inspection apparatus, especially the other form of the pulse magnetic field generation part 12 is demonstrated. 2 to 4, the same members as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The nondestructive inspection apparatus 20 shown in FIG. 2 differs from the nondestructive inspection apparatus 10 shown in FIGS. 1 and 6 in that the exciting coil 12f is wound around the long side portion of the yoke 12a. It is the same as the device 10. Thus, even when the exciting coil 12f is wound around the long side portion of the yoke 12a, a magnetic flux similar to the arrow shown in FIG. 5 can be generated, so that the inspection can be performed by the same method as described above.

  The nondestructive inspection apparatus 30 shown in FIG. 3 has a configuration in which the nondestructive inspection apparatus 10 of FIG. 1 and the nondestructive inspection apparatus 20 of FIG. 2 are combined, that is, excitation coils in the vicinity of both ends (short sides) of the yoke 12a. 12b and 12c are wound, and the exciting coil 12f is wound around the long side portion of the yoke 12a. Even with such a configuration, a magnetic flux similar to the arrow shown in FIG. 5 can be generated, so that the inspection can be performed in the same manner as described above. According to the non-destructive inspection apparatus 30, the number of excitation coils can be increased and the magnetic flux density is increased. Therefore, the SN ratio at the time of detecting a magnetic field response signal is improved, and more accurate detection is possible.

  The nondestructive inspection apparatus 40 shown in FIG. 4 is different from the nondestructive inspection apparatus 10 shown in FIGS. 1 and 6 in that the tip shape of both ends of the yoke 41a is a convex curved surface. This is the same as the inspection apparatus 10. The tip surfaces 41d and 41e at both ends of the yoke 41a can be, for example, spherical surfaces or spheroidal surfaces. At the time of inspection, the tip surfaces 41d and 41e are inspected by making contact with the object to be inspected at points, so that even when the surface of the object to be inspected has irregularities, the tip surfaces 41d and 41e are surely attached to the object to be inspected. The air gap between the object to be inspected and the yoke 41a can be eliminated. As a result, the SN ratio at the time of detecting the magnetic field response signal is improved, and more accurate detection is possible.

  The non-destructive inspection apparatuses 10, 20, 30, and 40 shown in FIGS. 1 to 4 are different in the tip shape of the both ends of the yoke and the winding method of the excitation coil, but all use a magnetic field response to a pulsed magnetic field. This is a non-destructive inspection device, and includes a U-shaped yoke and an exciting coil wound around the yoke.

  In other words, these devices have yokes formed in a U shape so that the tips of both ends can be in contact with the object to be inspected, and both ends of the yoke are wound around the yoke and energized. An excitation coil that forms a magnetic field through the tips of both ends of the yoke with respect to the object to be inspected that is in contact with the tip of the test piece, and can be used for nondestructive inspection using a magnetic field response to a pulsed magnetic field Inspection equipment.

  As described above, according to the above-described nondestructive inspection apparatuses 10, 20, 30, and 40, it is possible to provide a nondestructive inspection apparatus that can be easily installed regardless of the shape of the object to be inspected in the nondestructive inspection using the pulse magnetic field. .

  Next, an embodiment of a nondestructive inspection apparatus that can connect a plurality of pulsed magnetic field generators will be described. FIG. 7 is a schematic view showing a nondestructive inspection apparatus according to an embodiment of the present invention, FIGS. 8A and 8B are diagrams for explaining a connecting portion, and FIGS. 9 to 11 are drawings for inspection using the nondestructive inspection apparatus of FIG. FIG. 12A is a diagram illustrating an example, FIG. 12A is a diagram illustrating an example of a non-destructive inspection apparatus connected in series, and FIG. 12B is a diagram illustrating an example of a non-destructive inspection apparatus connected in parallel.

  As shown in FIG. 7, the nondestructive inspection apparatus 60 is obtained by providing two sets of connection portions 61 and 62 to the nondestructive inspection apparatus 10 shown in FIG. The connecting portion 61 includes a pair of plugs 61a and 61b and a flexible wiring 61c provided on the back side of the yoke 12a, and a pair of jacks 61e and 61f provided on the front side of the yoke 12a so as to face the flexible wiring 61c. And a connector 61d. Similarly, the connecting portion 62 is provided on the back side of the yoke 12a with a pair of plugs 62a, 62b and a flexible wiring 62c, and on the front side of the yoke 12a with the flexible wiring 62c, and is connected to a pair of jacks 62e, And a connector 62d having 62f. Thereby, the connection parts 61 and 62 can connect the nondestructive inspection apparatuses 60 so that attachment or detachment is possible.

  The plugs 61a, 61b, 62a, and 62b are terminals that are electrically connected by being inserted into jacks 61e, 61f, 62e, and 62f of other nondestructive inspection devices 60, respectively. A description will be given using 8B. The flexible wirings 61c and 62c are flexible wirings formed by covering the wirings with a resin, for example, and can be bent or bent in FIG.

  Two wires pass through each of the flexible wires 61c and 62c. One wiring in the flexible wiring 61c is connected to the plug 61a at one end of the flexible wiring 61c opposite to the yoke 12a, and the other end connected to the yoke 12a of the flexible wiring 61c is connected to the exciting coil 12b. Connected to one end. The other end of the exciting coil 12b is connected to one jack 61e of the connector 61d. The other wiring in the flexible wiring 61c is connected to the plug 61b at one end opposite to the yoke 12a of the flexible wiring 61c, and the other end of the connector 61d is connected to the yoke 12a of the flexible wiring 61c. To the jack 61f. That is, the plug 61a is electrically connected to the jack 61e via the exciting coil 12b, and the plug 61b is electrically connected directly to the jack 61f.

  Similarly, one wiring in the flexible wiring 62c is connected to the plug 62a at one end of the flexible wiring 62c opposite to the yoke 12a, and excited at the other end connected to the yoke 12a of the flexible wiring 62c. It is connected to one end of the coil 12c. The other end of the exciting coil 12c is connected to one jack 62e of the connector 62d. The other wiring in the flexible wiring 62c is connected to the plug 62b at one end of the flexible wiring 62c opposite to the yoke 12a, and the other end of the flexible wiring 62c connected to the yoke 12a is the other end of the connector 62d. To the jack 62f. That is, the plug 62a is electrically connected to the jack 62e via the exciting coil 12c, and the plug 62b is electrically connected directly to the jack 62f.

  FIG. 8A is a plan view of the vicinity of the plug 61a and the jack 61e between adjacent nondestructive inspection apparatuses, and FIG. 8B is a plan view of the state where the plug 61a and the jack 61e of FIG. 8A are connected. Since the other plugs 61b, 62a, 62b and the jacks 61f, 62e, 62f have the same configuration, detailed description thereof is omitted. The tip 61g of the plug 61a has a substantially conical shape larger than the columnar axis of the plug 61a. On the other hand, the jack 61e has a cylindrical shape having a diameter larger than that of the plug 61a so that the plug 61a and the tip 61g thereof can be inserted. A part of the inner wall of the jack 61e is cut away to form a recess (not shown), and a ball 61h is installed in the recess. The recess forms an opening in the inner wall of the jack 61e, but the ball 61h has a diameter that is slightly larger than the opening, and therefore does not fall into the jack 61e. The ball 61h is urged toward the inner peripheral side by a spring or the like (not shown) from the outer peripheral side of the inner wall of the jack 61e. With such a configuration, a part of the ball 61h protrudes from the opening into the jack 61e and can be retracted into the recess when pressed.

  With such a configuration, when the plug 61a is inserted into the jack 61e, the tip 61g of the plug 61a pushes the ball 61h, and the ball 61h returns to its original position after passing through the tip 61g, thereby completing the connection. The state shown in FIG. 8B is obtained. After the connection between the plug 61a and the jack 61e is completed, the plug 61a cannot be pulled out with an external force applied when the non-destructive inspection apparatus 60 is used.

  A plurality of such non-destructive inspection devices 60 can be used in combination. 9 and 10 show the state of inspection using a nondestructive inspection apparatus 70 configured by connecting a plurality of nondestructive inspection apparatuses 60. The nondestructive inspection device 70 connects the plugs and jacks of adjacent nondestructive inspection devices 60 in a plurality of nondestructive inspection devices 60, and as shown in FIG. 11, FIG. 12A or FIG. 60 connectors 61d and 62d are connected to the pulse current source 11, and plugs 61a, 61b, 62a and 62b of the non-destructive inspection device 60 at the other end are appropriately connected.

  Further, in the nondestructive inspection apparatus 70, it is sufficient that at least one of the pulse current source 11, the magnetic detection unit 13, the moving unit 14, and the control unit 15 is provided. For example, the magnetic sensor 13a may be provided in any one of the yokes 12a, may be provided in all the yokes 12a, or may be provided in every other yoke 12a. It may be provided on the alternate yoke 12a. The number of the magnetic sensors 13a can be determined as appropriate depending on the sensitivity of the magnetic sensor 13a and the depth of the flaw of the object to be inspected.

  The nondestructive inspection device 70 has a crawler shape (so-called caterpillar shape) or a bowl shape, and has a rectangular cross-section pipe 55 (see FIG. 9) or a circular cross-section pipe 56 depending on the flexibility of the flexible wirings 61c and 62c. It can be inspected by wrapping around an inspected object having various cross-sectional shapes such as (see FIG. 10). Further, by appropriately adjusting the number of connections of the non-destructive inspection device 60, it is possible to wind in a state in which the non-destructive inspection device 60 is in close contact with the inspection object having various diameters. Moreover, when a to-be-inspected object is plate shape, it can spread and install without winding. According to such a non-destructive inspection apparatus 70, both end portions of the yoke 12a can be reliably brought into contact with the surface of the object to be inspected regardless of the shape and size of the object to be inspected, and high accuracy cannot be detected. be able to.

  FIG. 12A is an example of a nondestructive inspection apparatus 70 configured by directly connecting a nondestructive inspection apparatus 60. In the nondestructive inspection device 60 at one end of the nondestructive inspection device 70, a jack 61 e is connected to one end of the pulse current source 11, and a jack 62 e is connected to the other end of the pulse current source 11. And in the nondestructive inspection apparatus 60 of the other end of the nondestructive inspection apparatus 70, the plug 61a and the plug 62a are connected. By connecting in this way, the nondestructive inspection device 70 forms a series connection circuit. In the case of series connection, the wiring to the pulse current source 11 is less than that in parallel connection.

  FIG. 12B is an example of a nondestructive inspection apparatus 70 configured by connecting the exciting coils 12b and 12c of the nondestructive inspection apparatus 60 in parallel. In the nondestructive inspection device 60 at one end of the nondestructive inspection device 70, the jack 61e and the jack 62f are connected to one end of the pulse current source 11, respectively, and the jack 61f and the jack 62e are connected to the other end of the pulse current source 11, respectively. Yes. In the nondestructive inspection device 60 at the other end of the nondestructive inspection device 70, the plug 61a and the plug 661b are connected, and the plug 62a and the plug 62b are connected. By connecting in this way, the nondestructive inspection device 70 forms a parallel connection circuit.

  Since the non-destructive inspection apparatus 70 can detect the same method as described above in any of the series connection circuit and the parallel connection circuit, what type of connection circuit is used depends on the capacitance of the pulse current source 11, the exciting coil 12b, It can be appropriately determined according to the heat generation of 12c, use conditions, and the like.

  The apparatus described above is a nondestructive inspection apparatus using a magnetic field response to a pulsed magnetic field, and includes a U-shaped yoke and an exciting coil wound around the yoke.

  In other words, the above-described apparatus has a yoke that is formed in a U shape so that the tips of both ends thereof can contact the object to be inspected, and both ends of the yoke are wound around the yoke and energized. An excitation coil that forms a magnetic field through the tips of both ends of the yoke with respect to the object to be inspected that is in contact with the tip of the test piece, and can be used for nondestructive inspection using a magnetic field response to a pulsed magnetic field Inspection equipment.

  In the above non-destructive inspection apparatus, the exciting coil may be wound around both ends of the yoke.

  In the nondestructive inspection apparatus described above, the tip shapes at both ends of the yoke may be convex curved surfaces.

  In the nondestructive inspection apparatus, a magnetic sensor for detecting a magnetic field response may be provided on the yoke.

  Further, the above-described nondestructive inspection apparatus may be provided with a connecting portion that electrically connects the nondestructive inspection apparatuses with flexibility so as to be detachable.

  In the nondestructive inspection apparatus, a plurality of the nondestructive inspection apparatuses may be connected, and a magnetic sensor for detecting a magnetic field response may be provided in at least one of the yokes.

  According to the nondestructive inspection apparatus described above, by using a U-shaped yoke around which an exciting coil is wound, it can be easily installed in a nondestructive inspection using a pulsed magnetic field regardless of the shape of the object to be inspected. .

10, 20, 30, 40, 60, 70 Nondestructive inspection apparatus 12a, 41a Yoke 12b, 12c Excitation coil 13a Magnetic sensor 41d, 41e Tip surface (convex curved surface)
61, 62 connection

Claims (6)

A non-destructive inspection device using a magnetic field response to a pulsed magnetic field,
U-shaped yoke,
A nondestructive inspection apparatus comprising: an exciting coil wound around the yoke.   The non-destructive inspection apparatus according to claim 1, wherein the exciting coils are wound around both end portions of the yoke.   The nondestructive inspection apparatus according to claim 1, wherein the tip shape of both end portions of the yoke is a convex curved surface.   The nondestructive inspection apparatus according to claim 1, wherein a magnetic sensor for detecting a magnetic field response is provided in the yoke.   The nondestructive inspection apparatus according to any one of claims 1 to 3, further comprising a connection portion that is flexible and electrically connected so that the nondestructive inspection apparatuses are detachable. A plurality of nondestructive inspection devices according to claim 5 are connected,
A nondestructive inspection apparatus, wherein a magnetic sensor for detecting a magnetic field response is provided in at least one of the yokes.

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