Magnetic film cassette apparatus for radiographic testing

Abstract

A magnetic film cassette device for radiographic inspection is disclosed. A magnetic film cassette device for radiographic inspection according to one embodiment of the present invention comprises: a cassette body for receiving a film for radiographic inspection; a film receiving portion provided inside the cassette body and arranged in a stacked state with the film; a flexible opening provided on one side of the cassette body for inserting the film; a magnetic attachment portion including a row of circular magnets spaced apart along the longitudinal direction on one side edge portion and the other side edge portion of the cassette body, respectively, for magnetically coupling the cassette body to the outer surface of a curved surface of a predetermined inspection target; and an overlap reference portion for setting an overlap range such that the end portion of an adjacent other cassette body overlaps with the cassette body based on the position of a reference magnet placed on the end side of the cassette body among the row of circular magnets.

Description

Technology Field

[0001] The present invention relates to a magnetic film cassette device for radiographic inspection, and more specifically, to a magnetic film cassette device for radiographic inspection that can maintain a constant state of overlap of film imaging areas by magnetically attaching a cassette body containing a radiographic inspection film to the outer surface of the curved surface of an inspection target during a batch radiographic inspection of a steel container installed in a power generation product, oil refinery plant, and industrial plant, and by setting the overlap range between adjacent cassette bodies based on the position of a reference magnet. Background Technology

[0002] Containers installed in power generation facilities, oil refineries, and industrial plants can generally be manufactured by fabricating and welding steel, and radiographic testing, a type of non-destructive testing, may be performed to check for defects inside the welds.

[0003] Radiographic inspection is an inspection method that transmits radiation energy into the weld, acquires a radiograph, and interprets the acquired radiograph to detect defects such as pores, fusion failures, cracks, and slag inclusion within the weld.

[0004] In particular, for radiographic inspection of the circumferential welds and hemispherical header welds of a container, a method of performing batch imaging over the entire inspection section with a radioisotope source placed in the center of the container may be used. In this batch imaging method, cassettes containing radiographic films must be arranged continuously along the outer surface of the weld, and a certain overlap section must be formed between adjacent cassettes so that no imaging-missing area occurs.

[0005] However, conventionally, when attaching film cassettes to the outer surface of a weld, methods using separate fixing tools such as rubber bands, elastic ropes, tapes, and magnetic chucks were mainly used. This method had the problem of taking a lot of time to install the cassettes because, in this way, a worker at the site had to manually adjust the position of each cassette and then use a separate fixing tool to tie or press the cassettes to the outer surface of the object to be inspected.

[0006] In addition, since the circumferential welds of the container and the hemispherical header welds are formed on outer surfaces with curvature, it is difficult to uniformly adhere the flat cassette to the weld surfaces. If a portion of the cassette lifts or separates from the weld surface, the distance between the film and the object to be inspected becomes uneven, which may consequently degrade the clarity and image quality of the radiograph.

[0007] In particular, since the cassette placed in the lower area of ​​the circumferential weld is significantly affected by its own weight, there is a high probability that the cassette will sag downward or partially detach from the surface of the object being inspected during imaging. In such cases, quality issues such as distortion, blurring, or non-uniform density may occur in the radiograph of the relevant section, and re-imaging becomes necessary if the inspection standards are not met.

[0008] In addition, in conventional methods, the overlap range between adjacent cassettes is often set based on the operator's experience. In this case, the overlap width between cassettes may not be uniform; if the overlap width is insufficient, a missing shooting area may occur, and if the overlap width is excessive, problems such as unnecessarily increasing film usage and reading area may arise.

[0009] In addition, if the flexibility of the cassette opening is insufficient during the process of inserting film into the cassette or withdrawing film after shooting, the surface of the film or intensifying screen may be scratched or damaged. Furthermore, if the cassette body fails to sufficiently block external light, unnecessary exposure may occur on the film, which can lead to a deterioration in the quality of the radiograph.

[0010] Therefore, a radiographic film cassette structure is required that can quickly attach a film cassette to the curved outer surface of a container, ensure that the cassette body adheres uniformly to the surface of the weld, set a constant overlap range between adjacent cassettes, and prevent film damage during the film insertion and withdrawal process. Prior art literature

[0011] Korean Registered Utility Model Publication No. 20-0381706, Korean Registered Patent Publication No. 10-1223257 The problem to be solved

[0012] The present invention aims to provide a magnetic film cassette device for radiographic inspection that can prevent lifting and sagging of the cassette body during batch radiographic inspection of the circumferential welds and hemispherical header welds of a container by magnetically coupling the cassette body, which accommodates the radiographic inspection film, to the outer surface of the curved surface of the inspection target through a circular magnet.

[0013] In addition, the purpose is to provide a magnetic film cassette device for radiographic inspection that can uniformly overlap film imaging areas with a preset width by setting an overlap range with adjacent cassette bodies based on the position of a reference magnet placed on the end side of the cassette body.

[0014] In addition, the purpose is to provide a magnetic film cassette device for radiographic inspection in which the cassette body can be stably positioned in close contact with the outer surface of an object having curvature by spaced circular magnets along the longitudinal direction on both edges of the cassette body.

[0015] In addition, the purpose is to provide a magnetic film cassette device for radiographic inspection that can prevent damage to the film surface during the insertion and withdrawal process of the radiographic inspection film by providing a flexible opening on one side of the cassette body and placing a cotton fabric layer on the inner surface of the film receiving portion.

[0016] In addition, the purpose is to provide a magnetic film cassette device for radiographic inspection that can reduce cassette installation time and minimize re-imaging due to deterioration of radiographic image quality without using separate rubber bands and ropes by forming the cassette body with a blackout fabric that blocks the ingress of external light and integrating a magnetic attachment structure to the inspection target.

[0017] The problems that the present invention aims to solve are not limited to those mentioned above, and other problems that the present invention aims to solve that are not mentioned herein will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0018] A magnetic film device for radiographic inspection according to one embodiment of the present invention comprises: a cassette body for receiving a film for radiographic inspection; a film receiving portion provided inside the cassette body and arranged in a stacked state; a flexible opening provided on one side of the cassette body for inserting a film; a magnetic attachment portion including a row of circular magnets spaced apart along the longitudinal direction on the edge portion of one side of the cassette body and the edge portion of the other side of the cassette body, respectively, for magnetically coupling the cassette body to the outer surface of the curved surface of a preset inspection target; and an overlap reference portion for setting an overlap range such that the end portion of an adjacent other cassette body overlaps with the cassette body based on the position of a reference magnet placed on the end portion of the cassette body among the row of circular magnets. The overlap reference portion is characterized by providing the reference magnet as an overlap reference point so that, when the cassette body is continuously arranged along the curved surface direction of the inspection target, the imaging area of ​​the film overlaps with the imaging area of ​​an adjacent other film by a preset width.

[0019] In addition, the cassette body is characterized by comprising an outer layer formed of a blackout fabric that blocks the inflow of external light, a cotton fabric layer disposed on the inner surface of a film receiving portion and in contact with the film, and a coupling member provided on the outer surface of the outer layer and detachably coupled with an adjacent cassette body.

[0020] In addition, the flexible opening is characterized by including a film injection port formed to open a portion of the front of the cassette body, and a folding portion connected to one side of the film injection port and configured to be foldable along the insertion direction of the film.

[0021] Additionally, the magnetic attachment portion comprises a first magnet row arranged along one edge of the cassette body and a second magnet row arranged along the other edge of the cassette body and positioned at a location corresponding to the first magnet row in the width direction, wherein the first magnet row and the second magnet row are formed as circular magnets arranged at mutually spaced positions along the length direction of the cassette body.

[0022] In addition, the overlap reference portion indicates the overlap range of the cassette body such that the end portion of an adjacent other cassette body overlaps with the end portion of the cassette body based on the reference magnet, and the overlap range is characterized by being formed as a range in which the shooting area of ​​the film contained in the cassette body overlaps with the shooting area of ​​another film contained in an adjacent other cassette body by a preset width. Effects of the invention

[0023] The magnetic film cassette device for radiographic inspection according to the present invention has the effect of preventing lifting and sagging of the cassette body during batch radiographic inspection of the circumferential welds and hemispherical header welds of a container by magnetically coupling the cassette body, which accommodates the radiographic inspection film, to the outer surface of the curved surface of the inspection target through a circular magnet.

[0024] In addition, by setting the overlap range with adjacent cassette bodies based on the position of a reference magnet placed at the end of the cassette body, it has the effect of allowing the film shooting area to be uniformly overlapped with a preset width.

[0025] In addition, by spaced-apart circular magnets along the longitudinal direction on both edges of the cassette body, the cassette body can be stably and securely positioned along the outer surface of an inspection object having curvature.

[0026] In addition, by providing a flexible opening on one side of the cassette body and placing a cotton fabric layer on the inner surface of the film receiving portion, it has the effect of preventing damage to the film surface during the insertion and withdrawal process of the radiographic inspection film.

[0027] In addition, by forming the cassette body with blackout fabric that blocks the entry of external light and integrating a magnetic attachment structure to the inspection target, it has the effect of shortening cassette installation time and reducing re-imaging caused by degradation of radiographic image quality without using separate rubber bands or ropes. Brief explanation of the drawing

[0028] FIG. 1 is a diagram showing the configuration of a magnetic film cassette device for radiographic inspection according to an embodiment of the present invention. FIG. 2 is a drawing illustrating the appearance of a magnetic film cassette device for radiographic inspection according to an embodiment of the present invention attached to an inspection target. Specific details for implementing the invention

[0029] Specific details regarding the problem to be solved, the means for solving the problem, and the effects of the invention as described above are included in the embodiments and drawings to be described below. The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings.

[0030] Hereinafter, the present invention will be described in more detail with reference to the attached drawings.

[0031] FIG. 1 is a diagram showing the configuration of a magnetic film cassette device for radiographic inspection according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating the appearance of a magnetic film cassette device for radiographic inspection according to an embodiment of the present invention attached to an object to be inspected.

[0033] Referring to FIG. 1, the magnetic film cassette device (100) for radiographic inspection of the present invention may include a cassette body (110), a film receiving part (120), a flexible opening part (130), a magnetic attachment part (140), and an overlap reference part (not shown).

[0034] The above cassette body (110) may be provided as a portion for receiving a radiographic inspection film (10). The film receiving portion (120) may be provided inside the cassette body (110) and may form a space in which the film (10) is arranged in a stacked state. Here, the film (10) may be received in the film receiving portion (120) in a state where the radiographic inspection film and the intensifying screen are stacked together.

[0035] The flexible opening (130) may be provided on one side of the cassette body (110) and may be formed with a structure that can be opened so that the film (10) can be inserted into the interior of the film receiving portion (120). At this time, the flexible opening (130) may be provided to allow bending deformation during the insertion and withdrawal process of the film (10), and accordingly, surface damage to the film (10) may be reduced during the process of inserting the film (10) into the cassette body (110).

[0036] The magnetic attachment part (140) may be provided on one edge and the other edge of the cassette body (110), respectively. The magnetic attachment part (140) may include a row of circular magnets spaced apart from each other along the longitudinal direction of the cassette body (110), and may magnetically attach the cassette body (110) to the outer surface of the curved surface of a preset inspection target.

[0037] The above overlap reference section can be implemented based on the position of a reference magnet placed at the end side of the cassette body (110) among the circular magnet rows. More specifically, the overlap reference section can set an overlap range such that the end of an adjacent cassette body overlaps with the cassette body (110).

[0038] At this time, the overlapping reference part is not limited to a separate independent member in the drawing, but can be understood as a functional configuration formed by the arrangement position of the end-side reference magnet among the circular magnet rows forming the magnetic attachment part (140).

[0039] Accordingly, when the cassette body (110) is continuously arranged along the curved direction of the inspection target, the shooting area of ​​the film (10) can overlap with the shooting area of ​​an adjacent film by a predetermined width.

[0040] That is, the operator can align the ends of adjacent cassette bodies using the position of the reference magnet as an overlap reference point, thereby maintaining a constant overlap width between the cassette bodies.

[0042] More specifically, the cassette body (110) may include an outer layer, a cotton fabric layer, and a bonding member. The outer layer may be formed of a blackout fabric that blocks the ingress of external light. The cotton fabric layer may be placed on the inner surface of the film receiving portion (120) and may be provided in a portion that contacts the film (10). Accordingly, the surface of the film (10) may be prevented from being scratched by the inner surface of the cassette body (110) during the process of the film (10) being inserted into the film receiving portion (120) or withdrawn from the film receiving portion (120).

[0043] For example, the coupling member may be provided on the outer surface of the outer shell layer and may be detachably coupled with an adjacent cassette body. The coupling member may be placed in an area on the outer surface of the cassette body (110) that overlaps with an adjacent cassette body. Accordingly, when the cassette body (110) is placed on the outer surface of the curved surface of the object to be inspected, it is possible to prevent the relative position with respect to an adjacent cassette body from easily becoming distorted.

[0044] Additionally, the coupling member may be configured to assist in the detachable coupling between adjacent cassette bodies, separately from the magnetic coupling with the inspection target by the magnetic attachment part (140). Accordingly, the cassette body (110) can be continuously arranged in a state where it is magnetically attached to the outer surface of the curved surface of the inspection target and simultaneously coupled with other adjacent cassette bodies. This reduces the unevenness of spacing, sagging, and overlapping ranges between cassette bodies during the batch radiographic inspection process.

[0046] Meanwhile, the flexible opening (130) may include a film injection port formed so that a portion of the front of the cassette body (110) is opened, and a folding portion connected to one side of the film injection port and configured to be foldable along the insertion direction of the film (10).

[0047] More specifically, the film injection port may be provided as an open area on one side of the front of the cassette body (110) so that the film (10) can be inserted into the interior of the film receiving portion (120). The film injection port may be formed with a width corresponding to the insertion width of the film (10) so that the widthwise end of the film (10) does not get caught, and may provide a path for the film (10) to enter the interior of the film receiving portion (120).

[0048] The above-mentioned folding portion may be connected to one side of the film injection port and may be arranged to elastically fold or unfold along the direction of movement of the film (10) during the process of inserting the film (10). Accordingly, the folding portion may guide the insertion of the film (10) by deforming in correspondence with the insertion position of the film (10) without strongly pressing the surface of the film (10) when the film (10) passes through the film injection port.

[0049] Additionally, the folded portion can be returned to cover at least a portion of the film injection port after the film (10) is inserted into the film receiving portion (120). Accordingly, the inflow of external light through the film injection port can be reduced, and the film (10) can be prevented from escaping to the outside of the cassette body (110).

[0050] For example, the above-mentioned folding portion may be formed from a blackout fabric identical to the outer layer of the cassette body (110) and may be provided in the form of a soft sheet that can be repeatedly bent and deformed according to the insertion and withdrawal of the film (10). In this case, the flexible opening (130) may form a structure that allows the insertion and withdrawal of the film (10) through the film injection port, while partially closing the film injection port when ready for shooting.

[0052] Meanwhile, the magnetic attachment part (140) may include a first magnet row arranged along one edge of the cassette body (110) and a second magnet row arranged along the other edge of the cassette body (110) and positioned at a location corresponding to the width direction of the first magnet row. At this time, the first magnet row and the second magnet row may be formed as circular magnets arranged at positions spaced apart from each other along the length direction of the cassette body (110).

[0053] More specifically, the first magnet row may be arranged in an up-and-down direction along one edge of the cassette body (110), and the second magnet row may be arranged in an up-and-down direction along the other edge of the cassette body (110). The first magnet row and the second magnet row may be positioned at corresponding locations with respect to the width direction of the cassette body (110), so that the two edges of the cassette body (110) can be magnetically coupled in a balanced manner to the outer surface of the curved surface of the object to be inspected.

[0054] For example, the circular magnets may be spaced at intervals of about 80 mm, and the spacing may be adjusted according to the total length of the cassette body (110), the curvature of the object to be inspected, the weight of the cassette body (110), and the required adhesion force.

[0055] The circular magnet may be fixed to the outer layer of the cassette body (110) or positioned inserted between the outer layer and the cotton fabric layer. In this case, the circular magnet can transmit magnetic force to the curved outer surface of the object to be inspected without protruding excessively from the outer surface of the cassette body (110). Accordingly, when the cassette body (110) is attached to the outer surface of the object to be inspected, unnecessary deformation of the position of the film (10) received in the film receiving portion (120) can be reduced.

[0056] In addition, since the first magnet row and the second magnet row are arranged along both edges of the cassette body (110), they may not interfere with the shooting area of ​​the film (10) accommodated in the central area of ​​the cassette body (110).

[0057] That is, the circular magnet can be placed in an edge area outside the shooting area of ​​the film (10), thereby reducing unnecessary interference in the reading area of ​​the radiographic image.

[0058] In addition, the first magnet row and the second magnet row can simultaneously support both sides of the cassette body (110) against the curved outer surface of the inspection target. Accordingly, even when the cassette body (110) is placed on an inspection target having curvature, such as a circumferential weld or a hemispherical header weld, it can be maintained in a state where both edges are in close contact together, rather than in a state where only one edge is attached and lifted.

[0060] Meanwhile, the above overlap reference part may indicate the overlap range of the cassette body so that the end part of an adjacent other cassette body overlaps with the end side area of ​​the cassette body (110) based on the reference magnet.

[0061] At this time, the overlap range may be formed as a range in which the shooting area of ​​the film (10) contained in the cassette body (110) overlaps with the shooting area of ​​another film contained in an adjacent cassette body by a predetermined width.

[0062] More specifically, the overlap reference portion can be implemented by the position of a reference magnet placed at the end side of the cassette body (110) among the circular magnet rows forming the magnetic attachment portion (140). That is, the reference magnet performs the function of magnetically attaching the cassette body (110) to the outer surface of the curved surface of the inspection target, and at the same time, can act as a reference point for setting the overlap range with an adjacent cassette body.

[0063] The reference magnet may be placed at the longitudinal end of the cassette body (110), and the operator may align the end of an adjacent cassette body based on the position of the reference magnet. Accordingly, even when the cassette body (110) and an adjacent cassette body are arranged continuously along the curved surface direction of the inspection target, the overlap width between the cassette bodies can be formed according to a certain standard without relying solely on the operator's experience.

[0064] For example, the overlap range may be set to a width of about 1 inch. In this case, the operator may position the other cassette body so that the end of the adjacent other cassette body corresponds to the position of the reference magnet, thereby allowing the shooting area of ​​the film (10) contained in the cassette body (110) and the shooting area of ​​the other film contained in the other cassette body to overlap by a width of about 1 inch.

[0065] In addition, the overlap reference part can be configured to utilize the position of the end-side magnet among the circular magnet rows of the magnetic attachment part (140), so that the overlap position between cassette bodies can be guided without adding a separate scale member or indicator member. Accordingly, the structure of the cassette body (110) can be kept simple, while ensuring the continuity of the film imaging area required for batch radiographic inspection.

[0066] In addition, the above-mentioned overlap reference section can be applied even in situations where the cassette body (110) is continuously arranged in a curved direction according to the curvature of the inspection target. That is, even when adjacent cassette bodies are not arranged only in a straight direction, but are arranged in a curved direction along the outer surface of a circumferential weld or a hemispherical header weld, the ends of each cassette body can be arranged to overlap based on the position of the reference magnet. By doing so, the occurrence of missing imaging areas can be reduced, and reading continuity between adjacent films can be maintained.

[0068] Meanwhile, the magnetic film cassette device (100) for radiographic inspection according to the present invention may further include a placement condition calculation unit that calculates a cassette placement stability index based on the mass of the cassette body (110), the reference magnetic force of the circular magnet, the spacing of the circular magnet, the radius of curvature of the inspection target, and the overlap width of the film.

[0069] That is, the placement condition calculation unit can calculate the overlap range according to the placement position of the reference magnet so that the cassette placement stability index is greater than or equal to a preset reference value.

[0070] More specifically, the above-mentioned placement condition calculation unit may receive the radius of curvature of the inspection target, the mass of the cassette body (110), the reference magnetic force of the circular magnet, the placement spacing of the circular magnet, and the actual overlap width of the film (10) as input values ​​or recall them as stored reference values ​​during the preparation stage before shooting. Based on the above-mentioned input values, the above-mentioned placement condition calculation unit may calculate a cassette placement stability index (CI) that reflects the degree to which the cassette body (110) stably adheres to the outer surface of the curved surface of the inspection target and the degree to which the overlap width with adjacent other cassette bodies conforms to a reference range.

[0071] At this time, the above cassette placement stability index (CI) can be calculated based on the following [Equation 1].

[0073] [Mathematical Formula 1]

[0074]

[0075] Here, CI is the cassette placement stability index, and N m is the number of circular magnets acting on the cassette body (110), and F m is the reference magnetic force of a single circular magnet, κ is the magnetic force reduction factor due to surface separation, and d c is a curved surface separation value that can occur between the cassette body (110) and the outer surface of the curved surface of the inspection target, and M c is the mass of the cassette body (110) containing the film (10), g is the acceleration due to gravity, θ is the downward sagging angle at the position where the cassette body (110) is attached on the outer surface of the curved surface of the inspection target, and W o is the actual overlap width with an adjacent cassette body, and W t is the preset standard overlap width, and α represents the correction factor for the overlap width error.

[0077] N of the numerator in the above [Mathematical Formula 1] m ·F mmay refer to the basic magnetic force magnitude provided by the magnetic attachment part (140). Also, e -κdc It may be an anti-magnetic agent that reflects the characteristic that the effective magnetic force contributing to actual attachment decreases as the distance between the cassette body (110) and the test target increases due to the curvature of the test target.

[0078] Accordingly, if the spacing between the circular magnets is excessively wide or the radius of curvature of the object to be inspected is small, and the cassette body (110) is not sufficiently in contact with the outer surface of the curved surface, the cassette placement stability index (CI) may be lowered.

[0079] In addition, M in the denominator of the above [Mathematical Formula 1] c ·g·(1+sinθ) may represent the degree to which the cassette body (110) tends to sag or be separated from the outer surface of the curved surface of the inspection target due to its own weight. In particular, when the cassette body (110) is placed in the lower region of the circumferential weld, the influence of the downward sagging angle θ increases, so the placement condition calculation unit can calculate a lower cassette placement stability index (CI) in the lower placement region even under the same magnetic force conditions.

[0080] In addition, e of the above [Mathematical Formula 1] -α|(Wo-Wt) / Wt| is the actual overlap width W o A standard overlap width W t It may be an overlap width correction term that reflects the degree of deviation from. That is, the actual overlap width W o A standard overlap width W t The closer it is to, the closer the above correction term has to 1, and the actual overlap width W o A standard overlap width W t In cases where it is excessively small or large, the above correction term may be reduced. Accordingly, the above placement condition calculation unit may not only determine whether the cassette body (110) is attached to the inspection target, but also reflect whether the shooting area of ​​adjacent films overlaps by a certain width.

[0082] Meanwhile, the above-mentioned curved surface separation value d c It can be calculated by the following [Mathematical Formula 2].

[0084] [Mathematical Formula 2]

[0085]

[0086] Here, P m is the spacing between the circular magnets forming the circular magnet row, and R may be the radius of curvature of the inspection target. [Equation 2] may be an equation for approximately calculating the maximum degree of separation that may occur in the intermediate region between the spaced-apart circular magnets when the cassette body (110) is placed on the outer surface of the curved surface. That is, the spacing P between the circular magnets m As this increases, the surface separation value d c increases, and as the radius of curvature R of the inspection target increases, the surface separation value d c It can decrease.

[0088] The above placement condition calculation unit can compare the cassette placement stability index (CI) calculated according to [Equation 1] with a preset standard stability index. At this time, if the cassette placement stability index (CI) is greater than or equal to the standard stability index, the above placement condition calculation unit can determine that the current circular magnet placement spacing, standard magnet position, and overlap width are suitable as placement conditions for the cassette body (110) on the outer surface of the curved surface of the inspection target.

[0089] Conversely, if the above cassette placement stability index (CI) is less than the above standard stability index, the placement condition calculation unit may calculate placement conditions such as adjusting the overlap range according to the position of the standard magnet, reducing the placement spacing of the circular magnet, or changing the attachment position of the cassette body (110). Accordingly, the magnetic film cassette device (100) for radiographic inspection can quantitatively provide cassette placement conditions suitable for batch radiographic inspection by considering together the curvature of the inspection target, the adhesion force of the magnet row, the weight of the cassette body (110), and the overlap width of the film imaging area.

[0090] For example, the above placement condition calculation unit is the placement spacing P of the circular magnet. m If this is 80mm and the radius of curvature R of the inspection target is 500mm, the surface separation value d according to [Equation 2] above c can be calculated to be approximately 1.6 mm. At this time, the number of circular magnets N acting on the cassette body (110) m There are 8 of these, and the reference magnetic force F of a single circular magnet m This is 12N, the magnetic force reduction coefficient κ due to curved surface spacing is 0.08, and the mass M of the cassette body (110) containing the film (10) is c When the weight is 0.6 kg and the cassette body (110) is placed in the lower region of the circumferential weld and the downward sagging angle θ is set to 60 degrees, the placement condition calculation unit can reflect the adhesion force due to magnetic force and the sagging effect due to self-weight together according to [Equation 1].

[0091] Also, the standard overlap width W t α is 25.4mm, and the actual overlap width W oWhen the measurement is 25mm, the actual overlap width is close to the reference overlap width, so the overlap width correction term can be calculated as a value close to 1. Accordingly, the above placement condition calculation unit calculates the above cassette placement stability index (CI) as greater than or equal to the preset reference stability index, and can determine that the current reference magnet position and overlap range are appropriate.

[0092] Conversely, the actual overlap width W o If measured as 15mm, the standard overlap width W t As the difference increases, the overlap width correction term decreases, and the cassette placement stability index (CI) can be calculated to be less than the reference stability index. In this case, the placement condition calculation unit can calculate a placement condition that resets the overlap range so that the end of an adjacent other cassette body is closer to the position of the reference magnet.

[0093] In this way, the above-described placement condition calculation unit can quantitatively determine the cassette placement state by reflecting not only whether the cassette body (110) is attached to the inspection target, but also the radius of curvature of the inspection target, the spacing of the circular magnets, the weight of the cassette body (110), the sagging effect due to bottom placement, and the overlap width of the film imaging area. Accordingly, the operator can adjust the attachment position of the cassette body (110), the overlap position according to the reference magnet, and the placement conditions of the circular magnet row based on the above-described cassette placement stability index (CI), and thereby reduce lifting, sagging, and omission of the imaging area of ​​the cassette body (110) during the batch radiographic inspection process.

[0095] Meanwhile, as another example, the film receiving portion (120) may be configured to receive the film (10) and the intensifying sensor in a stacked state. In this case, the film (10) and the intensifying sensor may be arranged in a state of surface contact with each other inside the film receiving portion (120), and as the cassette body (110) is magnetically attached to the outer surface of the curved surface of the object to be inspected, the contact state between the film (10) and the intensifying sensor can be stably maintained. Accordingly, lifting or misalignment between the film (10) and the intensifying sensor during the radiographic inspection process can be reduced, and the deterioration of the image quality of the radiograph can be prevented.

[0097] Additionally, the circular magnet forming the magnetic attachment part (140) may be provided as an anisotropic magnet in which the magnetization direction is formed in a predetermined direction. More specifically, the circular magnet may be positioned so that magnetic force acts toward the outer surface of the curved surface of the inspection target along the thickness direction of the cassette body (110). Accordingly, the circular magnet can provide concentrated magnetic force toward the inspection target from the edge portion of the cassette body (110), and the cassette body (110) can be maintained in a state of close contact with the outer surface of the inspection target having curvature.

[0099] Additionally, the circular magnet can be configured to provide a magnetic force that prevents the cassette body (110) from being separated from the outer surface of the curved surface of the inspection target during shooting, while also having a magnetic force within a range that allows an operator to separate the cassette body (110) from the inspection target after shooting is completed. That is, the magnetic force of the circular magnet can be configured by considering the weight of the cassette body (110), the stacking state of the film (10), the curvature of the inspection target, and the attachment position of the cassette body (110). Accordingly, the cassette body (110) can be stably attached to the inspection target during shooting and can be quickly collected after shooting is completed.

[0101] In addition, the outer layer of the cassette body (110) is formed of a blackout fabric, which not only blocks the entry of external light but also reduces the entry of moisture or contaminants into the interior of the film receiving portion (120) during field use. The blackout fabric may have durability to prevent the exterior of the cassette body (110) from being easily damaged during repeated attachment, detachment, and movement processes. Accordingly, the cassette body (110) can be used repeatedly in field environments such as power generation facilities, oil refineries, and industrial plants.

[0103] As described above, according to the present invention, a magnetic film cassette device for radiographic inspection can be provided, which prevents lifting and sagging of the cassette body during batch radiographic inspection of the circumferential weld and hemispherical header weld of a container by magnetically coupling the cassette body, which accommodates the radiographic inspection film, to the outer surface of the curved surface of the inspection target through a circular magnet.

[0104] In addition, a magnetic film cassette device for radiographic inspection can be provided, which allows the film imaging area to be uniformly overlapped with a preset width by setting the overlap range with an adjacent cassette body based on the position of a reference magnet placed at the end side of the cassette body.

[0105] In addition, by spaced circular magnets along the longitudinal direction on both edges of the cassette body, a magnetic film cassette device for radiographic inspection can be provided, which allows the cassette body to be stably positioned in close contact with the outer surface of an object having curvature.

[0106] In addition, by providing a flexible opening on one side of the cassette body and placing a cotton fabric layer on the inner surface of the film receiving portion, a magnetic film cassette device for radiographic inspection can be provided that prevents damage to the film surface during the insertion and withdrawal process of the radiographic inspection film.

[0107] In addition, by forming the cassette body with a blackout fabric that blocks the ingress of external light and integrating a magnetic attachment structure to the object of inspection, it is possible to provide a magnetic film cassette device for radiographic inspection that can shorten the cassette installation time and reduce re-imaging due to deterioration of radiographic image quality without using separate rubber bands and ropes.

[0109] As illustrated in FIG. 2, a magnetic film cassette device (100) for radiographic inspection according to one embodiment of the present invention may be arranged continuously along the outer surface of a curved object. The object may be provided as a steel container having a circumferential weld or a hemispherical header weld formed thereon, and the cassette body (110) may be arranged along the curved direction corresponding to the shape of the outer surface of the object.

[0110] At this time, the cassette body (110) can be magnetically attached to the outer surface of the curved surface of the inspection target by the magnetic attachment part (140). Accordingly, the operator can easily attach the cassette body (110) to the inspection target, and the cassette body (110) may sag downward due to its own weight during shooting or become separated from the outer surface of the inspection target.

[0111] Additionally, the cassette body (110) may be positioned so that its end portion overlaps with that of an adjacent cassette body. In this case, the overlap reference portion may set the overlap range based on the position of a reference magnet placed at the end of the circular magnet row forming the magnetic attachment portion (140), and accordingly, the shooting area of ​​the film (10) contained in the cassette body (110) and the shooting area of ​​an adjacent film may overlap by a predetermined width.

[0112] Accordingly, as shown in FIG. 2, when the magnetic film cassette device (100) for radiographic inspection is continuously arranged along the outer surface of the curved surface of the inspection target, the occurrence of missed areas during batch radiographic inspection can be reduced, and the close contact and overlapping state of the cassette body (110) can be maintained consistently to prevent deterioration of the image quality of the radiographic photograph.

[0114] As described above, although an embodiment of the present invention has been explained by limited embodiments and drawings, the embodiment of the present invention is not limited to the embodiments described above, and various modifications and variations are possible from this description by those skilled in the art to which the present invention pertains. Accordingly, an embodiment of the present invention should be understood only by the claims described below, and all equivalent or analogous variations thereof shall be considered to be within the scope of the inventive concept. Explanation of the symbols

[0116] 10: Film 110 : Cassette body 120 : Film receiving section 130 : Flexible opening 140 : Magnetic attachment part 150 : Overlap reference part

Claims

Claim 1 A cassette body for receiving a film for radiographic inspection; a film receiving portion provided inside the cassette body and arranged in a laminated state; a flexible opening provided on one side of the cassette body for inserting the film; a magnetic attachment portion including a row of circular magnets spaced apart along the longitudinal direction on one side edge and the other side edge of the cassette body, respectively, for magnetically coupling the cassette body to the outer surface of a pre-set curved surface of an inspection target; and an overlap reference portion for setting an overlap range such that the end of an adjacent other cassette body overlaps the cassette body based on the position of a reference magnet placed on the end side of the cassette body among the row of circular magnets; wherein the overlap reference portion provides the reference magnet as an overlap reference point so that, when the cassette body is continuously arranged along the direction of the curved surface of the inspection target, the imaging area of ​​the film overlaps with the imaging area of ​​an adjacent other film by a pre-set width; and the cassette body comprises an outer layer formed of a blackout fabric that blocks the ingress of external light; A magnetic film cassette device for radiographic inspection, characterized by comprising: a cotton fabric layer disposed on the inner surface of the film receiving portion and in contact with the film; and a coupling member provided on the outer surface of the outer skin layer and detachably coupled to an adjacent cassette body. Claim 2 delete Claim 3 A magnetic film cassette device for radiographic inspection according to claim 1, wherein the flexible opening comprises: a film injection port formed such that a portion of the front of the cassette body is opened; and a folding portion connected to one side of the film injection port and configured to be foldable along the insertion direction of the film. Claim 4 A magnetic film cassette device for radiographic inspection according to claim 1, wherein the magnetic attachment portion comprises: a first magnet row arranged along one edge portion of the cassette body; and a second magnet row arranged along the other edge portion of the cassette body and positioned at a position corresponding to the first magnet row in the width direction; wherein the first magnet row and the second magnet row are formed as circular magnets arranged at positions spaced apart from each other along the length direction of the cassette body. Claim 5 A magnetic film cassette device for radiographic inspection according to claim 1, wherein the overlap reference portion indicates an overlap range of the cassette body such that the end portion of an adjacent other cassette body overlaps with the end portion side area of ​​the cassette body based on the reference magnet, and the overlap range is formed as a range in which the imaging area of ​​the film contained in the cassette body overlaps with the imaging area of ​​another film contained in an adjacent other cassette body by a preset width.

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