JP2008064550A - Tank inspection device and tank inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect the arrangement of a sealant by a simple structure for a tank which keeps a cap provided with the sealant integrated with a liner. <P>SOLUTION: The tank inspection device 70 comprises rotary bases 72 for rotating the liner 30 about its axis and an eccentricity measuring apparatus 74 for measuring the eccentricity of the cap 10 with respect to the rotation axis. The liner 30 which keeps the cap 10 integrated is mounted on the rotary bases. The eccentricity measuring apparatus 74 is set on the outer periphery of the cap 10. The liner 30 is rotated about its central axis. When the amount of eccentricity detected by the eccentricity measuring apparatus 74 exceeds a predetermined allowable range A, it is judged that the sealant squeezes out of a groove of the cap. When the integration part between the liner and the cap can be seen structurally, it can be indirectly detected that the sealant is squeezes out of the groove of the cap by detecting a gap between the liner and the cap. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tank inspection device and a tank inspection method, and more particularly to a tank inspection device and a tank inspection method for a tank in which a base provided with a seal member is assembled to a liner.

  For example, hydrogen is used as a fuel gas in a fuel cell system, and the pressure is appropriately reduced from a tank filled with high-pressure hydrogen, and the flow rate is controlled and supplied to the fuel cell. Such a high-pressure gas tank is provided with a base for entering and exiting high-pressure gas. The base is provided with a seal member so that gas does not leak between the base and a cylindrical member constituting the tank body. For example, the seal member is disposed in a groove provided in the base and is assembled to the liner together with the base. However, if the seal member is not properly disposed between the liner and the base, gas leakage may occur. .

  As a method for confirming the arrangement of the sealing member, Patent Document 1 discloses that a tank in which high-pressure hydrogen gas is injected and a carbon fiber is disposed around an aluminum tank, between the base and the aluminum tank. Several methods have been described for detecting a seal failure in the inner and outer seal members where is sealed with the inner and outer seal members. For example, in a tank into which high-pressure gas has been injected, a communication path in which one end opens in a gap formed between the inner seal member, the outer seal member, the tank body, and the base, and the other end opens to the outside air side. It is possible to detect a defect or the like of the inner seal member by a pressure gauge provided at the atmospheric pressure side end of the communication path.

  Patent Document 2 discloses a method for measuring a gap between a seal portion attached to a stationary portion of a rotating device such as a steam turbine and a rotating body that is a rotor. Here, the stationary part can be divided into an upper stationary part and a lower stationary part. In the upper opening state where there is no upper stationary part, an acceleration sensor is attached to the rotating body, and the gap measuring scope is placed between the rotating body and the sealing part. The separation plate provided with the seal portion is lifted with respect to the rotating body, and the contact of the seal portion with the rotating body is detected by an acceleration sensor, and the gap measurement scope is measured at that time. Based on the value, the size of the gap is determined.

  Further, in Patent Document 3, the insertion port of the other tube is inserted into the receiving port of one tube, and the sealing material is compressed between the inner peripheral surface of these receiving ports and the outer peripheral surface of the insertion port. In a so-called slip-on type pipe joint that forms a joint, an inspection device that detects a displacement of a sealing material by remote operation is disclosed. Here, a fixing member that is removably attached to the outer periphery of the pipe joint, a moving member that is movable in the tube axis direction with respect to the fixing member, a mounting member attached to the moving member, Using a special inspection device equipped with a gauge that is inserted from the gap between them until it hits the sealing material, the moving member is automatically moved in the tube axis direction, and the insertion amount of the gauge at that time is detected. It is possible to inspect the displacement of the sealing material in the tube axis direction in the gap between the opening and the insertion opening.

JP 2005-291434 A JP 2000-249537 A Japanese Patent Laid-Open No. 06-249646

  When the base provided with the seal member is assembled to the liner which is a component of the tank, it can be easily confirmed whether or not the seal member is properly arranged on the base before the assembly. However, once the base provided with the seal member is assembled to the liner, the seal member is hidden in the base even if the seal member is displaced from the groove during the assembly operation. Cannot be confirmed easily. Therefore, several methods have been disclosed as described above. However, the method of Patent Document 1 is an inspection method for a seal member provided in a base in a tank in which high-pressure gas has already been injected, A complicated structure is provided in the base, and a pressure gauge or the like is required. In addition, inspection cannot be performed in a state before the high-pressure gas is injected, and protrusion from a normal arrangement of the seal member cannot be detected. In addition, the method of Patent Document 3 requires a special remote inspection device, and the method of Patent Document 2 is an inspection method in an upper opening state where there is no upper stationary portion, and a partition plate provided with a seal portion is provided. An operation to lift the rotating body is required, and the protrusion of the seal portion from the normal arrangement cannot be detected.

  As described above, in the related art, a base having a seal member is assembled to the liner, and a complicated configuration is required to confirm the arrangement of the seal member in a state where the state of the seal member cannot be confirmed from the outside.

  An object of the present invention is to provide a tank inspection device and a tank inspection method capable of inspecting protrusions from a normal arrangement of a seal member with a simple configuration with respect to a tank in which a base provided with a seal member is assembled to a liner. It is to be.

  A tank inspection apparatus according to the present invention is a tank inspection apparatus for a tank in which a base provided with a seal member is assembled to a liner, and the base provided with a seal member in a circumferentially provided groove is used as a liner. After the assembly and the state of the seal member cannot be directly confirmed from the outside, the seal member has a protrusion detection means for indirectly detecting that the seal member protrudes from the groove of the base.

  The protrusion detection means includes a gap detection means for detecting a gap between the base and the liner from the inside of the tank, and when the detected gap is larger than a predetermined gap amount, the seal member is It is preferable to include a determination unit that determines that the protrusion protrudes from the groove.

  The gap detection means is preferably an imaging device that observes the gap from the inside of the tank. Alternatively, the gap detection means preferably detects the gap from the inside of the tank using a gap gauge having a predetermined thickness.

  Further, in the tank inspection apparatus according to the present invention, when the eccentricity detecting means detects the eccentricity of the base with respect to the central axis of the liner, and when the detected eccentricity is larger than a predetermined eccentricity, the sealing member is It is preferable to include a determination unit that determines that the protrusion protrudes from the groove.

  Further, the tank inspection method according to the present invention is a tank inspection method for a tank in which a base provided with a seal member is assembled to a liner, and a base provided with a seal member in a circumferentially provided groove is provided. An assembling step for assembling the liner, and a protrusion detecting step for indirectly detecting that the sealing member protrudes from the groove of the base under the condition that the state of the sealing member cannot be directly confirmed from outside by the assembling. , Including.

  Further, the tank inspection method according to the present invention is a tank inspection method for a tank in which a base provided with a seal member is assembled to a liner, and a base provided with a seal member in a circumferentially provided groove is provided. A rotation process for rotating the liner around its central axis after the assembly of the seal member and the seal member cannot be confirmed directly from the outside, and an eccentricity detecting means for detecting the eccentricity of the base with respect to the central axis of the liner Using an eccentricity detecting step of detecting the eccentricity of the base when the liner is rotated, and a determining step of determining whether the seal member protrudes from the groove of the base based on the detected eccentricity data. It is characterized by including.

With the above-described configuration, the tank inspection device includes the protrusion detection unit that indirectly detects that the seal member protrudes from the groove of the base. Depending on the structure of the liner of the tank to which the base is attached, the assembly portion between the liner and the base may be structurally visible or not visible. , Indirectly detecting that the seal member protrudes from the groove of the base.

  In the former case, where the assembly portion between the liner and the base can be structurally viewed, the protrusion detection means detects the gap between the base and the liner from the inside of the tank, and the detected gap is arbitrarily set in advance. When the clearance is larger than the determined gap amount, it is determined that the sealing member protrudes from the groove of the base. Therefore, it is possible to inspect the protrusion of the seal member from the normal arrangement with a simple configuration.

  Since the gap detection means is an imaging device that observes the gap from the inside of the tank, it can easily detect that the seal member protrudes from the groove of the base. Similarly, when the gap is detected from the inside of the tank using a gap gauge having a predetermined thickness, the gap detection means can easily detect that the seal member protrudes from the groove of the base.

  In the latter case, where the assembly part between the liner and the base cannot be structurally seen, the eccentricity of the base with respect to the central axis of the liner is detected, and the detected eccentricity is larger than a predetermined amount of eccentricity. It is determined that the sealing member protrudes from the groove of the base. Therefore, it is possible to inspect the protrusion of the seal member from the normal arrangement with a simple configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the tank is a high-pressure hydrogen tank used for a fuel cell mounted on a vehicle, but may be a tank for other purposes. In addition, the tank is formed by a filament winding method in which a resin reinforcing fiber is wound around a core material called a liner. However, as long as the base can be attached to the liner, the manufacturing method and configuration of the tank are other than that. It may be.

  Prior to the description of the tank inspection apparatus and the like, a base provided with a seal member and a liner to which the base is attached will be described with reference to FIGS. FIG. 1 is a perspective view of a base 10 provided with a seal member, and FIG. 2 is a view showing a relationship between a liner 30 and the base 10.

  A base 10 shown in FIG. 1 is a member having a stopper shape that is attached to a gas inlet / outlet opening 32 (see FIG. 2) of a liner 30 that is a component of a tank. For example, a connection such as a valve is attached. It is a member. The base 10 has a hole penetrating in the axial direction of the base body 12 having a stopper shape. Here, a lower opening 14 is shown in FIG. 1, and an upper opening 15 is shown in FIG. A valve or the like necessary for controlling the gas in and out is attached to the hole. As the base body 12, an appropriate metal material or a plastic material having an appropriate strength molded into a predetermined shape can be used.

  In the lower part of the base body 12, that is, in the part where the lower opening 14 is provided, the two grooves 16 and 18 provided circumferentially along the outer periphery are recesses for disposing the seal member. Three sealing members are used here. That is, in the upper groove, that is, the groove 16 closer to the upper opening 15 out of the two grooves, an annular O-ring having a circular cross section is disposed as the outer seal member 20. Of the two grooves, a groove 18 closer to the lower side, that is, closer to the lower opening 14 is provided with an annular O-ring having a circular cross section as the inner seal member 22. On the side of the upper opening 15, an annular rectangular ring having a rectangular cross section is disposed as the backup seal member 24. The backup seal member 24 may use one rectangular ring having a wide rectangular cross section, or a plurality of rings having a square cross section arranged side by side. These three sealing members can be made of a rubber material having elasticity. For example, plastic rubber O-rings and square rings can be used.

  FIG. 2 is a diagram illustrating a state in which the base 10 is incorporated into the opening 32 of the liner 30. Here, the liner 30 is a member that becomes a core material of the tank. Here, a high-pressure hydrogen tank used in a vehicle on which a fuel cell is mounted as a tank will be described. The tank is made by a filament winding method. Specifically, a tank is made by using a fiber having sufficient strength, for example, carbon fiber, impregnating it with a liquid resin, winding it around a liner that forms the shape of the product, and heating and curing the resin. The base 10 is assembled to the liner 30 serving as the core material.

  The liner 30 is a core material that shapes the shape of the molded product in this way. For example, when molding a high-pressure tank, the liner 30 is a cylinder corresponding to the inner diameter of the tank. As the material of the cylinder, for example, a hard plastic or a metal such as aluminum can be used. The diameter of the cylinder is, for example, about 30 cm, and the thickness thereof can be about several mm.

  As shown in FIG. 2, the liner 30 has an opening 32 for gas inlet / outlet, and the base 10 is assembled to the opening 32. A suitable press-fitting means is used for the assembly. By this press-fitting, the sealing member is sandwiched and compressed between the outer surface of the liner 30 and the grooves 16 and 18 of the base 10 described with reference to FIG. 1, thereby sealing between the base 10 and the liner 30. . When the sealing member protrudes out of the grooves 16 and 18 in this assembling operation or the like, a sealing failure occurs.

  In the following, the protruding inspection of the seal member will be described in two cases. This is a case where the assembly portion between the liner and the base can be structurally seen and cannot be seen from the structure of the liner of the tank to which the base is attached. First, the former case will be described, and then the latter case will be described.

  3 and 4 are partially enlarged cross-sectional views of the vicinity of the lower opening 14 of the base body 12 when the base is assembled to the opening for the gas inlet / outlet of the liner. FIG. 3 shows a state where the seal member is properly disposed, and FIG. 4 shows a state where the seal member protrudes from the groove.

  As shown in FIGS. 3 and 4, the opening portion for the gas inlet / outlet of the liner 30 has an annular mouth portion 31 that enters toward the inside of the liner 30, and the mouthpiece body 12 is provided in the mouth portion 31. Is press-fitted. After the press-fitting operation, the seal member is sandwiched between the outer surface of the mouth portion 31 of the liner 30 and the base body 12, and the state cannot be directly observed from the outside.

  FIG. 3 is a cross-sectional view when the sealing member is properly disposed after the base is assembled to the liner. Here, a state in which the three seal members 20, 22, and 24 are compressed in the radial direction while being arranged in predetermined grooves is shown. In this case, no gas leakage occurs between the liner and the base.

  FIG. 4 is a cross-sectional view showing one example in which the seal member has been placed out of the groove after the base is assembled to the liner. In this example, a state in which the outer seal member 20 protrudes from the groove 16 to be originally disposed is shown. In this case, there is a risk of gas leakage between the liner and the base. When the seal member protrudes from the groove where the seal member should be originally disposed in this way, a gap 40 larger than usual is generated between the liner 30 and the base body 12.

  Therefore, when the assembly portion between the liner and the base can be structurally seen from the structure of the liner of the tank to which the base is attached, the gap detection means for detecting the gap 40 and the detected gap are The tank can be inspected by using a judging means for judging that the seal member protrudes from the groove of the base when the gap amount is larger than a predetermined amount. The liner 30 serves as a core of the tank. For example, when the liner 30 is a cylindrical member, a gap detecting means is inserted from the opening of the cylindrical bottom portion, and the mouth 31 of the liner 30 is inserted into the liner 30. It can be observed from the inside, that is, from a position corresponding to the inside of the tank.

  FIG. 5 is a diagram illustrating an example in which the tank inspection device 50 includes an imaging device 52 and an image analysis device 54. Here, the imaging device 52 corresponds to a gap detection unit, and the image analysis device 54 corresponds to a determination unit. The imaging device 52 is disposed at a position where the mouth portion 31 of the liner 30 can be observed from the inside of the liner 30. As the imaging device 52, for example, a CCD (Charge Coupled Device) camera can be used, and as the image analysis device 54, a PC (Personal Computer) capable of executing image display analysis software can be used.

  In the tank inspection device 50 in FIG. 5, since the imaging device 52 is arranged at a position where the gap between the liner 30 and the base body 12 can be observed, the data is transmitted to the image analysis device 54, and the image analysis device 54 It is displayed on the display 56. Therefore, the inspector recognizes the pattern of the liner 30 and the base body 12 from the display 56 and uses the scale on the display 56 to determine the size of the gap 40 between the liner 30 and the base body 12. Can be sought. Further, the image analysis device 54 automatically detects the respective edges of the liner 30 and the base body 12 by, for example, a preset pattern recognition method, and automatically calculates and displays the size of the gap 40. It can also be. In this case, the size of the gap 40 is automatically compared with a predetermined gap amount threshold value, and when the obtained gap amount is larger than the threshold value, the seal member protrudes from the groove of the base. It can be determined that it is displayed on the display 56 or the like.

  FIG. 6 is a diagram showing an example in which a gap gauge 60 having a predetermined thickness is used as the gap detection means. The predetermined thickness is set to a limit thickness at which it can be determined that the seal member protrudes from the groove of the base when the gap 40 is equal to or greater than this thickness. When the gap gauge 60 is carefully used by an operator and can be inserted between the liner 30 and the base body 12, it can be determined that the sealing member protrudes from the groove of the base.

  In addition, a gauge movement detection device that can automatically move the gap gauge 60 having a predetermined thickness and can detect that it cannot move any further when a load is applied during movement is used as a tank inspection device. it can. In this case, the tank inspection device is set at a position where the gauge can be inserted at the boundary between the liner 30 and the base body 12, the gap gauge 60 is automatically moved, and the gap gauge 60 moves to the boundary. Is detected. When it is detected that the gap gauge 60 is moved and inserted into the boundary, it can be displayed that the seal member protrudes from the groove of the base.

  In this way, when the assembly portion between the liner and the base can be structurally seen from the structure of the tank liner to which the base is attached, the seal between the liner and the base is detected by detecting the gap between the liner and the base. Even after the state of the member cannot be directly confirmed from the outside, it can be indirectly detected that the seal member protrudes from the groove of the base.

  When the assembly between the liner and the base cannot be structurally seen from the structure of the liner of the tank to which the base is attached, by detecting the eccentricity of the base with respect to the liner, the sealing member is removed from the groove of the base. It can detect that it protrudes.

  FIG. 7 is a diagram showing a state of the tank inspection device 70 that inspects the tank by detecting the eccentricity of the base with respect to the central axis of the liner. The tank inspection device 70 detects the eccentricity of the rotating base 72 capable of rotating the liner 30 around the axial direction and the base 10 with respect to the rotating shaft, and displays whether the eccentricity is normal or abnormal. 74.

  As described above, the turntable 72 has a function of rotating the liner 30 around the axial direction, and can be configured by, for example, four rotating rollers that symmetrically support the outer periphery of the cylindrical liner 30. The rotating roller can rotate around an axis parallel to the reference plane, and is rotated by a rotating mechanism (not shown). Therefore, the liner 30 is placed around the central axis by placing the four rotary rollers so that the direction of the central axis of the liner 30 is aligned and rotating the rotary roller in a predetermined direction by a rotating mechanism (not shown). Can be rotated. As another method, the four rotating rollers are simply supported by a bearing mechanism, and a rotating mechanism for rotating the liner 30 may be provided separately. In this case, the liner 30 is rotated around the central axis by the rotation mechanism.

  The eccentricity measuring device 74 is a measuring instrument that is set so that the detector comes into contact with the outer periphery of the base 10 and has a function of detecting the displacement of the base 10. A typical example of such a measuring instrument is a dial gauge, but other displacement detectors can be used. The eccentricity measuring device 74 is previously provided with a mark indicating an allowable range A of displacement of the base 10. When the eccentricity measuring device 74 is an electronic type, when the detected amount of displacement exceeds the allowable range, that fact can be displayed. Here, it should be noted that the detected amount of displacement is twice the amount of eccentricity. In that sense, the eccentricity measuring device 74 has a function of an eccentricity detecting means and a function of a judging means for judging whether the amount of eccentricity is appropriate or inappropriate.

  If the allowable range A of the detected eccentric amount is the same as the threshold value of the gap 40 described in FIGS. 4 and 5, the seal member protrudes from the groove of the base when the eccentric amount exceeds the allowable range A. It can be judged.

  However, the roundness of the outer circumference of the liner 30 and the roundness of the outer circumference of the base 10 need to be within appropriate ranges. When these roundness values are within appropriate ranges, the central axis of the liner 30 and the central axis of the cap 10 are substantially concentric and coincide with each other when there is no gap 40 described with reference to FIGS. To do. When there is a gap 40, the central axis of the base 10 is eccentric with respect to the central axis of the liner 30 by the gap 40. In this way, the eccentricity measuring device 74 detects the eccentricity of the base 10 with respect to the central axis of the liner 30, and based on the detected amount, it can be determined whether or not the seal member protrudes from the groove of the base.

  Note that the method using the tank inspection device 70 can also be applied to a tank by the filament winding method with the liner 30 as a core material. That is, when the roundness of the outer periphery of the tank and the roundness of the outer periphery of the base 10 are within appropriate ranges, the eccentricity of the base 10 with respect to the central axis of the tank is detected. The protrusion of the seal member from the groove of the base can be detected.

  FIG. 8 is a flowchart showing a procedure of a tank inspection method for inspecting the tank as to whether or not the seal member protrudes from the groove of the base by detecting the eccentricity of the central axis of the base with respect to the central axis of the liner. Here, the symbols described in FIG. 7 are used. In order to specify the inspection object, first, the liner 30 and the base 10 are prepared (S10). Here, a predetermined seal member is disposed in the groove of the base 10. Next, the base 10 is assembled to the liner 30 using an appropriate press-fitting device (S12). Thereby, the liner 30 assembled with the base 10 to be inspected is completed. The liner 30 with the cap is placed on the turntable (S14). Then, the eccentricity measuring device 74 is set on the outer periphery of the base 10 (S16), and the liner 30 is rotated around its central axis (S18). Then, it is determined whether or not the amount of eccentricity detected by the eccentricity measuring device 74 is equal to or smaller than a predetermined allowable range A (S20). When the amount of eccentricity is equal to or smaller than the allowable range A, it is normal (S22). When the allowable range A is exceeded, it is determined that the seal member protrudes from the groove of the base (S24).

  In this way, when the assembly portion between the liner and the base cannot be structurally seen from the structure of the liner of the tank to which the base is attached, by detecting the eccentricity of the base with respect to the central axis of the liner, Even after the state of the seal member becomes a state that cannot be directly confirmed from the outside, it can be indirectly detected that the seal member protrudes from the groove of the base.

In embodiment which concerns on this invention, it is a perspective view of the nozzle | cap | die provided with the sealing member. In embodiment which concerns on this invention, it is a figure which shows the relationship between a liner and a nozzle | cap | die. In embodiment which concerns on this invention, it is a figure which shows the case where the sealing member is arrange | positioned appropriately. In embodiment which concerns on this invention, it is a figure which shows a mode when the sealing member has protruded from the groove | channel. In embodiment which concerns on this invention, it is a figure which shows the example comprised including an imaging device and an image analyzer as a tank test | inspection apparatus. In embodiment which concerns on this invention, it is a figure which shows the example which uses the clearance gauge which has predetermined | prescribed thickness as a clearance detection means. In embodiment which concerns on this invention, it is a figure which shows the mode of the tank test | inspection apparatus which test | inspects a tank by detecting the eccentricity of the nozzle | cap | die with respect to the center axis | shaft of a liner. In embodiment which concerns on this invention, it is a flowchart which shows the procedure of the tank test | inspection method which test | inspects a tank by detecting eccentricity of the nozzle | cap | die with respect to the center axis | shaft of a liner.

Explanation of symbols

  10 base, 12 base body, 14 lower opening, 15 upper opening, 16, 18 groove, 20 outer seal member, 22 inner seal member, 24 backup seal member, 30 liner, 31 mouth portion, 32 opening portion, 40 gap, 50, 70 Tank inspection device, 52 imaging device, 54 image analysis device, 56 display, 60 gap gauge, 72 turntable, 74 eccentricity measuring device.

Claims (7)

A tank inspection device for a tank in which a base provided with a seal member is assembled to a liner,
After the die having the seal member disposed in the circumferential groove is assembled to the liner and the seal member cannot be confirmed directly from the outside, the seal member is protruded from the groove of the die. A tank inspection apparatus comprising a protrusion detection means for indirectly detecting the spillage. In the tank inspection apparatus according to claim 1,
The protrusion detection means
A gap detecting means for detecting a gap between the base and the liner from the inside of the tank;
A judging means for judging that the seal member protrudes from the groove of the base when the detected gap is larger than a predetermined gap amount;
A tank inspection apparatus comprising: In the tank inspection apparatus according to claim 2,
The tank inspection device, wherein the gap detection means is an imaging device that observes the gap from the inside of the tank. In the tank inspection apparatus according to claim 2,
The tank inspection device, wherein the gap detection means detects a gap from the inside of the tank using a gap gauge having a predetermined thickness. In the tank inspection apparatus according to claim 1,
An eccentricity detecting means for detecting the eccentricity of the base with respect to the central axis of the liner;
A judging means for judging that the seal member protrudes from the groove of the base when the detected eccentricity is larger than an arbitrarily determined eccentric amount;
A tank inspection apparatus comprising: A tank inspection method for a tank in which a base provided with a seal member is assembled to a liner,
An assembling step of assembling a base having a sealing member disposed in a circumferential groove on a liner;
A protrusion detection step of indirectly detecting that the seal member protrudes from the groove of the base under the condition that the state of the seal member cannot be directly confirmed from the outside by assembly;
A tank inspection method comprising: A tank inspection method for a tank in which a base provided with a seal member is assembled to a liner,
A rotating step of rotating the liner around its central axis after assembling a base having a sealing member in a circumferentially provided groove to the liner and the state of the sealing member cannot be directly confirmed from the outside; ,
An eccentricity detecting step of detecting eccentricity of the base when the liner is rotated using an eccentricity detecting means for detecting the eccentricity of the base relative to the central axis of the liner;
A determination step of determining whether or not the seal member protrudes from the groove of the base based on the detected eccentricity data;
A tank inspection method comprising:

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