KR102416524B1 - an testing apparatus and testing method for liquefied gas tank - Google Patents

Abstract

The present invention relates to a liquefied gas storage tank inspection apparatus and method, which forms a storage space for accommodating liquefied gas and inspects the barrier for a liquefied gas storage tank having an insulating wall and a barrier, and is fixed to the insulating wall a rubbing part for rubbing the barrier; a transfer unit for moving the rubbing unit on the barrier; and an analysis unit for evaluating the degree of installation of the barrier based on noise or vibration generated during rubbing by the rubbing unit.

Description

Liquefied gas storage tank testing apparatus and method {an testing apparatus and testing method for liquefied gas tank}

The present invention relates to a liquefied gas storage tank inspection apparatus and method.

According to recent technology development, liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG) is widely used to replace gasoline or diesel.

LNG in ships that transport or store liquefied gas such as LNG at sea, LNG RV (Regasification Vessel), LNG FPSO (Floating, Production, Storage and Offloading), and LNG FSRU (Floating Storage and Regasification Unit) A liquefied gas storage tank (referred to as a "cargo hold") is installed to store the liquefied gas in a cryogenic liquid state.

In the liquefied gas storage tank, boil-off gas (BOG) may be generated by heat intrusion from the outside, and the natural vaporization rate (BOR), which is the vaporization ratio of the boil-off gas, must be lowered through an adiabatic design. In addition, leakage of liquefied gas or boil-off gas should be prevented.

Accordingly, such a liquefied gas storage tank may have at least two layers of insulation space and a double insulation barrier, and may include an IBS (Interbarrier Space), a secondary barrier, an IS (Insulation Space), The first barrier is provided.

In constructing such a liquefied gas storage tank, the construction result of the barrier is tested to prevent leakage from the secondary barrier, etc., and continuous research and development are being made on a test method that can be quickly and accurately verified.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to provide an apparatus and method for inspecting a liquefied gas storage tank that can easily, quickly and accurately check whether there are defects in a barrier, etc. .

A liquefied gas storage tank inspection device according to an aspect of the present invention forms a storage space for accommodating liquefied gas and inspects the barrier for a liquefied gas storage tank having an insulating wall and a barrier, and is fixed to the insulating wall a rubbing part for rubbing the barrier; a transfer unit for moving the rubbing unit on the barrier; and an analysis unit for evaluating the degree of installation of the barrier based on noise or vibration generated during rubbing by the rubbing unit.

Specifically, the barrier includes a connection barrier for sealing between a heat insulating wall-side barrier provided on the heat-insulating wall, and the heat-insulating wall-side barrier disposed adjacent to each other by being adhered to a plurality of the heat insulating wall-side barriers disposed adjacent to each other; The rubbing unit may rub a portion of the connection barrier that is adhered to the barrier at the side of the insulating wall.

Specifically, the analysis unit may determine the adhesion defect of the barrier based on noise or vibration generated when air bubbles existing between the connection barrier and the barrier on the insulating wall side are pressed by rubbing.

Specifically, the rubbing part may be provided as a pair so as to simultaneously rub both side portions bonded to the insulating wall-side barrier in the connection barrier.

The liquefied gas storage tank inspection apparatus and method according to the present invention, in testing whether there is a risk of leakage after construction for a secondary barrier, etc., can provide a reliable test result that secures both speed and accuracy.

1 is a cross-sectional view of a liquefied gas storage tank according to the present invention.
2 is a conceptual diagram of a liquefied gas storage tank inspection apparatus according to a first embodiment of the present invention.
3 is a block diagram of a liquefied gas storage tank inspection apparatus according to a first embodiment of the present invention.
4 is a conceptual diagram of a liquefied gas storage tank inspection apparatus according to a second embodiment of the present invention.
5 is a block diagram of a liquefied gas storage tank inspection apparatus according to a second embodiment of the present invention.
6 is a flowchart of a liquefied gas storage tank inspection method according to a second embodiment of the present invention.
7 to 10 are views for explaining the inspection results of the liquefied gas storage tank inspection apparatus according to the second embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a liquefied gas storage tank according to the present invention.

First, before describing an embodiment of the present invention, a liquefied gas storage tank 1 to which the present invention is applied will be described with reference to FIG. 1 . For reference, below, the liquefied gas may be LPG, LNG, ethane, or the like, and may mean liquefied natural gas (LNG) by way of example.

In addition, the liquefied gas storage tank 1 to which the present invention is applied may be provided on a ship, in which case the ship is a liquefied gas carrier that transports liquefied gas as a cargo, or a liquefied gas propulsion ship or liquefied gas that uses liquefied gas as fuel. It may be a gas power plant, etc., and it is a concept that includes FSRU, FPSO, bunkering vessel, offshore plant, etc. in addition to merchant ships.

Referring to FIG. 1 , the liquefied gas storage tank 1 forms a storage space for accommodating the liquefied gas. The liquefied gas storage tank 1 may be of a stand-alone type or a membrane type, and in the case of a stand-alone type, it may encompass all of IMO Types A, B, C, and the like.

The liquefied gas storage tank (1) has heat insulating walls (11, 13) and a barrier (12). The liquefied gas storage tank 1 is to forcibly liquefy gas existing in the gas phase at room temperature and store it in a liquid phase, and it is necessary to prevent evaporation by maintaining the liquefied gas at a low temperature. Therefore, the liquefied gas storage tank (1) is provided with at least one layer of insulating walls (11, 13) to surround the storage space.

The heat insulating walls 11 and 13 may be made of various materials having heat insulating performance, for example, a polyurethane block or a polyurethane spray layer, or a heat insulating box filled with a heat insulating material such as perlite.

In addition, the liquefied gas storage tank 1 is provided with a barrier 12 in order not to leak the liquefied gas stored therein to the outside. Insulation walls 11 and 13 are provided for insulation, whereas leakage cannot be blocked. In order to compensate for this, a barrier 12 forming a membrane structure for blocking leakage of liquefied gas is provided.

However, the barrier 12 is difficult to implement a form of enclosing the storage space with one layer, so that a plurality of sheets overlap each other to form a barrier 12 completely enclosing the storage space.

The barrier 12 may be made of a material such as metal, and has a liquid-tight function to prevent leakage of liquefied gas, as well as to prevent leakage of boil-off gas in which liquefied gas evaporates in the liquefied gas storage tank 1 . Confidentiality may be provided.

The insulating walls 11 and 13 and the barrier 12 may be provided inside the wall constituting the shape of the liquefied gas storage tank 1 . However, when the insulating walls 11 and 13 are provided on the outside of the wall, a separate barrier 12 may not be added to the outside of the wall as the wall itself implements the function of the barrier 12 .

When the heat insulating walls 11 and 13 are provided inside the wall, the heat insulating walls 11 and 13 are fixed to the inner surface of the wall, and the barrier 12 can be laminated on the inner surface of the heat insulating walls 11 and 13. . In addition, the insulating walls 11 and 13 + the barrier 12 are stacked in plurality to implement double insulation, double sealing, and the like.

Referring to FIG. 1 as an example, the liquefied gas storage tank 1 may be a membranous tank, and insulating walls 11 and 13 are stacked on the inside with the hull 10 as a wall. At this time, the secondary insulating wall 11 may be laminated on the hull 10 through the mastic 112 , and the secondary insulating wall 11 has a fixing force with the hull 10 through the plywood 111 provided on the outer surface. can be obtained

The insulating wall-side barrier 121 is provided on the inner surface of the secondary heat insulating wall 11 , and the primary heat insulating wall 13 is provided on the inner surface of the heat insulating wall side barrier 121 . The primary insulating wall 13 has a structure symmetrical to the secondary insulating wall 11, and a plywood 131 may be provided on the inner surface, and a primary barrier (not shown) is welded to the plywood 131, etc. can be fixed to

The secondary insulating wall 11, the insulating wall side barrier 121, and the primary insulating wall 13 may form one unit block, and a plurality of unit blocks are attached to the inside of the hull 10 to provide a storage space. can be However, a gap exists between a pair of unit blocks, and insulation and sealing are required for the gap.

For this purpose, insulation may be made between the secondary heat insulating walls 11 facing each other through a separate heat insulating material (eg, glass wool). In addition, the connection barrier 122 is adhered to the barrier 121 on the side of the insulating wall that is disposed adjacent to each other, thereby sealingly finished.

At this time, the connection barrier 122 is fixed at both ends with an adhesive 123 to a pair of insulating wall-side barriers 121 that are spaced apart from each other, thereby covering the gap between the insulating wall-side barriers 121 to seal the storage space. can be implemented

However, if the insulation wall side barrier 121 and the connection barrier 122 are not properly bonded, there is a risk that boil-off gas or the like may leak to the outside through the poorly bonded portion. Therefore, in the present invention, the adhesive portion of the insulating wall-side barrier 121 and the connection barrier 122 can be inspected, which will be described in detail below.

In addition, when the unit block is installed, an insulating material (polyurethane, etc.) is also filled between the primary insulating walls 13 facing each other, and the inner surface of the primary insulating wall 13 is covered with a plurality of primary barriers in overlapping arrangement. do.

Therefore, the liquefied gas storage tank 1 according to FIG. 1 implements double insulation with the primary insulating wall 13 and the secondary insulating wall 11, and the secondary barrier 12 (insulation wall side barrier 121) + Double sealing can be implemented as a connection barrier 122) and a primary barrier.

Of course, the inspection device described below may be applied to a portion where the primary barrier is overlapped in addition to the secondary barrier 12 . Hereinafter, the liquefied gas storage tank inspection device 20 will be described in detail with reference to FIG. 2 and the like.

Figure 2 is a conceptual diagram of a liquefied gas storage tank inspection apparatus according to a first embodiment of the present invention, Figure 3 is a block diagram of a liquefied gas storage tank inspection apparatus according to the first embodiment of the present invention.

2 and 3, the liquefied gas storage tank inspection apparatus 20 according to the first embodiment of the present invention forms a storage space for accommodating liquefied gas, and the insulating walls 11 and 13 and the barrier 12 ) as an apparatus for inspecting the barrier 12 for the liquefied gas storage tank 1 having do.

The rubbing part 21 rubs the barrier 12 . The rubbing unit 21 may rub the barrier 12 fixed to the insulating walls 11 and 13 , and in particular, rubbing is implemented for the adhesive portion of the barrier 12 to be inspected.

The rubbing portion 21 may have a curved end while rubbing the barrier 12 to prevent damage to the barrier 12 and the like. For example, the rubbing part 21 forms a convex curved surface toward the barrier 12 at a portion in contact with the barrier 12 .

The rubbing part 21 is provided in the form of a bar in which the portion in contact with the barrier 12 forms a curved surface. The rubbing portion 21 may have a bar shape perpendicular to the barrier 12 as shown in the drawing, or may be formed in an inclined form in order to minimize the risk of damage to the barrier 12 .

The rubbing unit 21 is provided so as to be able to rub the inspection target site without omission, and for this purpose, the rubbing unit 21 is provided to move freely in the width and length directions. That is, the rubbing unit 21 may rub against the barrier 12 while moving in a zigzag shape.

As described above with reference to FIG. 1 , the portion inspected by the rubbing portion 21 may be a portion that is adhered to the barrier 121 on the side of the heat insulating wall in the connection barrier 122 . At this time, since both sides of the connection barrier 122 are adhered to the barrier 121 on the insulating wall side, the rubbing unit 21 is provided as a pair so as to simultaneously rub both sides of the connection barrier 122 attached to the barrier 121 on the insulating wall side. can be In this case, the movement of the pair of rubbing units 21 may be synchronized.

When the end area of the rubbing part 21 increases, the inspection time for the inspection site of the barrier 12 is shortened, but as the rubbing area of the end increases, it may be difficult to accurately find the defect. Therefore, in the present embodiment, the rubbing parts 21 having different end areas may be provided, and while rubbing is implemented with the rubbing parts 21 having the first size end areas, if a defect is identified, the rubbing part is smaller than the first size. Fine rubbing can be implemented with the rubbing part 21 having an end area.

For this purpose, the rubbing units 21 having different end areas may be replaced while being drawn in/withdrawn from the transfer unit 22 or rotated. Alternatively, while both the inner tube and the outer tube are rubbing the barrier 12 in the form of a double tube, it is also possible that the outer tube rises to implement rubbing only the inner tube. That is, the rubbing part 21 of the present embodiment can be modified as described above to achieve both the effect of reducing the inspection time and the effect of accurately locating the defective part.

The transfer unit 22 moves the rubbing unit 21 on the barrier 12 . Since the rubbing unit 21 can perform an inspection on the secondary barrier 12 , the transfer unit 22 can implement movement while being guided to the sidewall of the primary insulating wall 13 .

In this case, a groove (not shown) is formed at the lower end of the plywood 131 in the primary heat insulating wall 13 , and one end of the transfer unit 22 is inserted into the groove to be transferred while the transfer unit 22 is guided. And, this is to utilize the transport structure of the automatic bonding device for automatically bonding the connection barrier 122 .

Alternatively, a rail for movement of the transfer unit 22 may be installed on the plywood 131 of the primary insulating wall 13, etc., and the transfer unit 22 moves while pushing between the adjacent primary insulating walls 13 ) can be transferred without a separate fastening. Of course, the transfer unit 22 may use various methods in addition to the rubbing unit 21 to stably rub the barrier 12 .

However, there will be no problem if the transfer is implemented on the bottom surface of the liquefied gas storage tank 1, but when the transfer is implemented on the upper surface, the transfer unit 22 is stably guided so as not to fall on the primary insulating wall 13, etc. structure can be used.

That is, even if grooves or rails are not used on the bottom surface of the liquefied gas storage tank 1, the rubbing part 21 stably forms the barrier 12 by using grooves or rails on the upper surface of the liquefied gas storage tank 1, etc. ) can be rubbed.

The transfer unit 22 may implement transfer while maintaining an appropriate distance with the barrier 12 . Through this, the rubbing unit 21 increases the inspection accuracy by rubbing while applying a constant pressure to the barrier 12 .

Alternatively, the rubbing part 21 may be provided so that the end for rubbing the barrier 12 is elastically moved without being fixed at a predetermined position. That is, the rubbing portion 21 has a structure having an elastic force so that the end faces the barrier 12, and when a certain pressure or more is applied to the end when the curved end presses the barrier 12, the end is the barrier 12 It can be elastically deformed in a direction away from Through this, the rubbing part 21 rubs the front surface of the inspection part in the barrier 12 with a constant pressure.

The analysis unit 23 evaluates the degree of installation of the barrier 12 based on noise or vibration generated during rubbing by the rubbing unit 21 . The connection barrier 122 is adhered while the adhesive 123 is spread on the barrier 121 on the insulating wall side. At this time, air bubbles may be generated between the connection barrier 122 and the barrier 121 on the insulating wall side.

A non-adhesive portion such as a bubble forms an empty space between the connecting barrier 122 and the insulating wall-side barrier 121 compared to the adhesive portion. At this time, when the rubbing part 21 presses a certain point of the connection barrier 122 corresponding to the empty space, the connection barrier 122 is pressed toward the barrier 121 on the side of the insulating wall at that point, and the empty space is deformed. A small noise may occur.

Therefore, the analysis unit 23, the air bubbles present between the connection barrier 122 and the insulating wall-side barrier 121, are microscopically pushed out when pressed by rubbing and noise or vibration is generated based on the barrier 12 adhesive defects can be identified.

That is, the analysis unit 23 may have a noise sensor to detect that the bubble is pushed by the rubbing unit 21 and makes a squeaking sound, or the end of the rubbing unit 21 is shaken when the bubble is pressed. It may have a vibration sensor that checks the vibration.

Of course, all methods capable of collecting/confirming variables generated when the rubbing unit 21 rubs against a non-adhesive portion may be utilized by the analysis unit 23 .

The control unit 24 controls the rubbing unit 21 and the like described above. The control unit 24 transmits a control signal to each component included in the liquefied gas storage tank inspection device 20 in various ways, such as wired or wireless, to drive the rubbing unit 21, the transfer unit 22, etc. can be adjusted.

In addition, the control unit 24 may receive a control result from each configuration and implement integrated control of the liquefied gas storage tank inspection device 20 according to the control result. In addition, the control unit 24 may oversee various controls for efficient and rapid inspection of the liquefied gas storage tank inspection device 20 .

The output unit 25 outputs the inspection result. The output unit 25 may be configured to provide a result to the user with the naked eye, such as a display capable of outputting an image, and in addition, a configuration for outputting the result through various non-limited methods such as sound may be used.

The output unit 25 displays, for example, whether or not there is a defect and the degree of installation of the barrier 12 as a result value to the user, so that the construction quality of the barrier 12 can be intuitively confirmed.

As such, in this embodiment, the presence of a non-adhesive part is determined based on noise or vibration generated during rubbing while rubbing is applied to the adhesive part between the barriers 12 where there is a risk of leakage in the liquefied gas storage tank (1). By checking, it is possible to intuitively check whether there is a defect.

4 is a conceptual diagram of a liquefied gas storage tank inspection apparatus according to a second embodiment of the present invention, and FIG. 5 is a block diagram of a liquefied gas storage tank inspection apparatus according to a second embodiment of the present invention.

6 is a flowchart of a liquefied gas storage tank inspection method according to a second embodiment of the present invention, and FIGS. 7 to 10 are for explaining the inspection results of the liquefied gas storage tank inspection apparatus according to the second embodiment of the present invention It is a drawing.

4 to 10, the liquefied gas storage tank inspection apparatus 20 according to the second embodiment of the present invention, similar to the first embodiment described above, the connection barrier 122 in the insulating wall side barrier 121 Whether or not the bonded portion is defective can be checked, but it is different from the previous embodiment in the defect inspection principle and the like.

Hereinafter, the present embodiment will be mainly described on the points that are different from the previous embodiment, and the parts omitted from the description will be replaced with the previous content.

The liquefied gas storage tank inspection apparatus 20 of this embodiment includes an eddy current generator 26 , a sensing unit 27 , a defect detection unit 28 , a control unit 24 , and an output unit 25 .

In addition, the components shown in FIG. 5 are not essential to the implementation of the liquefied gas storage tank inspection apparatus 20, and the components of the liquefied gas storage tank inspection apparatus 20 may be more or less than the listed components. . This is also the same in the previous embodiment.

The eddy current generator 26 generates an eddy current in the barrier 12 to be inspected. In this embodiment, the barrier 12 can be inspected using a non-contact method, unlike the previous embodiment in which air bubbles or the like are detected through rubbing.

The barrier 12 of this embodiment includes metal sheets 121a and 121b, and at least two or more barriers 12 are stacked with each other to form an overlapping portion. Specifically, both the insulating wall side barrier 121 and the connection barrier 122 may include metal sheets 121a and 122a, and non-metal sheets 121b and 122b are laminated on both sides of the metal sheets 121a and 122a. It may be provided in a complex structure as a form. Alternatively, a composite structure in which the metal sheets 121a and 122a are laminated on both sides of the non-metal sheets 121b and 122b is also possible. Here, the metal sheets 121a and 122a may include, but are not limited to, aluminum, copper, or the like.

That is, in this embodiment, when the metal sheet 121a of the insulating wall side barrier 121 and the metal sheet 122a of the connection barrier 122 are overlapped with each other, eddy current flaw detection can be applied to the corresponding portion, and at this time, the overlapping Non-metal sheets 121b and 122b in addition to the adhesive 123 may be placed between the two metal sheets 121a and 122a in the portion. The defect detection unit 28 to be described later may perform the analysis in consideration of this point.

Specifically, the present embodiment may use an eddy current method (Eddy Current Array). The eddy current inspection method is a method of sending an eddy current to an inspection site and inspecting that the distribution of eddy current is distorted when cracks exist in the inspection site, and is one of the known non-destructive tests. The detailed principles of eddy current flaw detection related to the eddy current generator 26 and the sensing unit 27 to be described later are substituted for those already known.

For example, the eddy current generator 26 may use an excitation coil or the like. For example, the eddy current generator 26 receives a current from an external power supply (not shown, which may be included in the controller 24 ), and generates a magnetic field around the excitation coil.

As a result, by electromagnetic induction, an eddy current is generated in the vicinity of the surface of the measurement site in the barrier 12 made of metal. As the eddy current is generated on the surface of the measurement portion, the magnetic flux passes through the detection coil of the sensing unit 27, which will be described later, and an induced voltage is generated in the detection coil. The induced voltage may be measured by the detection coil, and the eddy current may be measured by the sensing unit 27 .

Both terminals of the excitation coil of the eddy current generator 26 may be connected to an AC power supply (AC), and the AC power is applied to the excitation coil by the controller 24 with a preset AC excitation signal (AC voltage signal for induction). do. On the other hand, both terminals of the detection coil of the sensing unit 27 are connected to the defect detection unit 28 .

Therefore, when an AC excitation signal is applied from an AC power source to the excitation coil, the magnitude of the detection signal (voltage signal according to the induced voltage) is obtained from the detection coil, and the phase difference (phase delay) of the detection signal to the AC excitation signal is detected. Through this, the defect detection unit 28 to be described later may determine whether the barrier 12 is defective.

The sensing unit 27 receives the distribution state of the eddy current generated by the eddy current generating unit 26 in the barrier 12 . As described above, when the eddy current generator 26 is formed of an excitation coil, the sensing unit 27 can be formed of a detection coil.

The sensing unit 27 receives an eddy current distribution state when an eddy current is generated through the eddy current generating unit 26 in a portion of the connection barrier 122 that is adhered to the insulating wall-side barrier 121, and receives the insulating wall-side barrier 121 ), the adhesive defect of the connection barrier 122 can be grasped.

In the present embodiment, the eddy current generator 26 and the sensing unit 27 may form a probe, and at least the sensing unit 27 of the present embodiment has a plurality of coils 241 in the connection barrier 122 . They are arranged to correspond to the width of the portion adhered to the barrier 121 on the insulating wall side, and in this case, the probe of this embodiment is composed of a multi-probe. Accordingly, when the sensing unit 27 senses once, sensing in the form of a line over the entire width of the inspection site is performed.

In addition, the sensing unit 27 may be provided as a pair so as to simultaneously scan both sides of the connection barrier 122 attached to the barrier 121 on the heat insulating wall side. Therefore, the pair of sensing units 27 are moved by the transfer unit 22 or manually changed in position by the user, so that both sides of the connection barrier 122 are skipped, thereby maximizing the inspection efficiency.

The defect detection unit 28 evaluates the installation degree of the barrier 12 based on a singular value that may be included in the eddy current distribution state. The defect detection unit 23 analyzes possible defects in the connection barrier 122 based on the detection signal of the sensing unit 27 . For example, possible defects include, but are not limited to:

Insufficient bonding width: When non-adhesive is formed at both ends of the bonding surfaces between the barriers 12 and the bonding width is less than the standard bonding width

Bubble: When a bubble is formed above the reference value in the bonding surface between the barriers 12

Adhesive uncured: When a portion where the adhesive is not partially cured is formed above the reference value in the adhesive surface between the barriers 12

Peeling: When the connection barrier 122 and the barrier 121 on the insulating wall side are separated from each other more than a certain part due to adhesion failure on the adhesive surface between the barriers 12

The control unit 24 controls the overall operation of the liquefied gas storage tank inspection device (20). The control unit 24 may process signals, data, information, etc. input or output through the above-described components.

In addition, the control unit 24 may operate by combining at least two or more of the components included in the liquefied gas storage tank inspection device 20 with each other. In addition, although the control unit 24 and the defect detection unit 28 have been separately described in the present invention, the control unit 24 may be implemented as one component including the above-described defect detection unit 28 . Hereinafter, it goes without saying that operations performed by the defect detection unit 23 may be performed through the control unit 24 .

The output unit 25 displays (outputs) information processed in the liquefied gas storage tank inspection device 20 . For example, the output unit 25 may output a defect detection result according to the control signal of the control unit 24 and provide it to the user.

Hereinafter, a method of detecting the defect detection unit 28 will be described in more detail with reference to FIG. 6 and the like.

Referring to FIG. 6 which is a flowchart, the sensing unit 27 may sense eddy current distribution data (S10). The eddy current distribution data may correspond to data sensed through the above-described eddy current array inspection.

For example, referring to FIG. 4 , the eddy current distribution data may include a value indicating a distance between the insulating wall-side barrier 121 to be inspected and the metal sheets 121a and 122a included in the connection barrier 122 . .

On the other hand, although not shown in the drawings, it is also possible to have three or more metal sheets 121a and 122a included in the insulating wall-side barrier 121 and the connecting barrier 122. It may correspond to a distance between the sheets 121a and 122a or a distance between the farthest metal sheets 121a and 122a.

In addition, as described above, since the sensing unit 27 is composed of a multi-probe, and can sense the width range of the connection barrier 122 at once, the sensing unit 27 moves with respect to the barrier 12 in the longitudinal direction while It is possible to sequentially sense the eddy current distribution data.

However, the reception of the eddy current distribution data as described above may be performed by the defect detection unit 28 instead of the sensing unit 27 as a main body. That is, the sensing unit 27 may be provided as a detection coil that transmits a detection signal to the defect detection unit 28 , and the defect detection unit 28 may receive the detection signal collected from the sensing unit 27 as eddy current distribution data.

Next, the defect detection unit 28 may correct the eddy current distribution data (S10). For example, based on the reference data, the eddy current distribution data may be corrected.

For example, the magnitude of the detection signal is collected by the defect detection unit 28 through the detection coil of the sensing unit 27, and the defect detection unit 28 is amplified to detect a phase difference between the detection signal and the AC excitation signal. As the detection, an AC excitation signal can be used.

In addition, the defect detection unit 28 may perform correction to remove noise signals that are determined to be irrelevant to the defect or interfere with the defect determination with respect to the detected signal.

Thereafter, the defect detection unit 28 may extract defect data from the correction data (S20). For example, the defect data is data suspected of having an adhesion defect between the insulating wall-side barrier 121 and the connection barrier 122 , and may correspond to a case in which a change occurs in the distance between metals included in the barrier 12 . . Meanwhile, the above-described data correction may be performed after the extraction of the defect data, unlike the above description, or may be performed even after the defect data is extracted from the eddy current distribution data in addition to the above description.

When the defect data is extracted, the defect detection unit 28 may determine whether the defect condition of the barrier 12 corresponds to the defect data from the defect data (S30). As an example, the defect determination condition may be under-adhesive width, bubble, adhesive non-curing, peeling, etc. as described above, and with reference to FIGS. 7 and 10 showing actual experimental examples for such defect determination, to be described in detail .

First, referring to FIG. 7, assuming cases 1 and 2, eddy current flaw detection was performed on the cases. However, in the case of Case 1, a case in which a tape was attached to form a non-adhesive part (Case 1-1) and a case in which the tape was removed (Case 1-2) were tested. For reference, in case 1, the case where the tape is located at the end of the width direction of the connection barrier 122 (when non-bonding exists in the adhesive surface) and the case where it is not located at the end (in the case of less than the adhesive width) can include all of them.

On the other hand, as described above, the possible defects may include insufficient bonding width, bubble generation, adhesive non-curing, peeling, and the like. The under-adhesive width corresponding to the adhesion defect may correspond to a case in which adhesion is not made to exceed a certain range at the end of the width direction of the connection barrier 122 . For example, the predetermined range may correspond to 1 to 50 mm in the inward direction from the distal end, and preferably may correspond to 1 to 10 mm.

In addition, the occurrence of bubbles corresponding to the adhesion defect may correspond to a case in which bubbles are generated in some areas when the connection barrier 122 and the barrier 122 on the insulating wall side are adhered. As an example, the bubble generation range may correspond to a case in which the diameter of a single bubble corresponds to 1 to 50 mm.

As another example, the bubble generation range may correspond to a case in which an area in which bubbles are generated on one barrier 12 exceeds 2% of an adhesion area. Also, as another example, the bubble generation range may correspond to a case in which the bubble string is present in the lateral direction among the bonding areas. The bubble string corresponds to the presence of non-adhesive portions in the longitudinal direction because foreign substances are included in the bonding area.

In addition, the adhesive non-curing corresponding to the adhesion defect corresponds to a case in which the inside of the adhesive layer between the connection barrier 122 and the insulating wall-side barrier 121 is not partially cured. In addition, peeling corresponding to an adhesion defect corresponds to a case in which adhesion of the adhesive layer on the side of the barrier 121 on the side of the connection barrier 122 or the side of the insulating wall is poor.

In the case of case 1 in FIG. 7, it may correspond to an under-adhesive width, uncured adhesive, and the like, and in the case of case 2, it may correspond to the occurrence of bubbles.

In this experiment, several experiments were performed on the barrier 12 of the composite structure manufactured by different manufacturers in the same case, and FIGS. 8 to 10 summarize the results of the two experiments.

Referring to Case 1-1 shown in (a) and (b) of FIG. 8 , the boundary of the non-adhesive portion is clearly identified when examining the screen showing the eddy current flaw detection result. In addition, it can be seen that the non-adhesive portion applied in Case 1-2 is accurately confirmed when referring to FIGS. 9 (a) and (b).

In addition, in the case of case 2 shown in (a) and (b) of Figure 10, it can be seen that the portion corresponding to the bubble is displayed so as to be distinguished.

That is, in this embodiment, as a result of applying the sensing unit 27 that implements eddy current flaw detection to the cases of FIG. 7 , a high reliability result can be obtained from the data analyzed by the defect detection unit 28 ( FIGS. 8 to 10 ). there was.

As described above, when it is determined that the defect data corresponds to the defect condition of the barrier 12 , the defect detection unit 28 may determine that an adhesion defect has occurred in the barrier 12 ( S41 ).

For example, referring to FIGS. 8 and 9 , when the location where the defect data occurs corresponds to the end of the adhesive part and the non-adhesive width exceeds 50 mm, the defect detection part 28 is the barrier 12 It can be judged that an adhesion defect has occurred.

In addition, referring to FIG. 10 , when the shape of the defect data is bubble-shaped and the diameter exceeds 50 mm, the defect detection unit 28 may determine that an adhesion defect has occurred in the barrier 12 .

Meanwhile, when the defect data corresponds to at least one of the barrier 12 defect conditions, the defect detection unit 28 may determine that an adhesion defect has occurred in the barrier 12 .

In addition, when the defect data does not correspond to the barrier 12 defect condition, the defect detection unit may determine that an adhesion defect in the barrier 12 does not occur ( S42 ). Although not shown in the drawing, when the defect data does not correspond to the above-described defect conditions such as an under-adhesion width condition, a bubble generation condition, etc., the defect detection unit 28 may determine that an adhesion defect within the barrier 12 does not occur. .

Next, the output unit 25 may output the defect determination result ( S50 ). For example, the control unit 24 may receive the determination result of the defect detection unit 28 and control to output the defect determination result to the output unit 25 . In addition, the output unit 25 may be controlled to output a result of determining a defect of the adhesive unit in real time according to the positional movement of the sensing unit 27 .

In this embodiment, the transfer unit 22 may be provided as in the previous embodiment. In this case, the transfer unit 22 may be detachably provided, and similarly to the first embodiment described above, the sensing unit 27 moves on the barrier 12 while being controlled by the control unit 24 . In this case, the transfer unit 22 may be guided by being inserted into the groove of the primary heat insulating wall 13 or a rail installed separately may be used, and a structure such as a wheel may be used.

The transfer unit 22 may be provided such that the sensing unit 27 does not move in the width direction but moves only in the length direction at the bonding portion of the connection barrier 122 and the barrier 121 on the heat insulating wall side.

As described above, the sensing unit 27 is formed of a multi-probe so that the width of the scan range may cover the width of the inspection portion. Therefore, sensing of the adhesive portion of the barrier 12 is implemented while the sensing unit 27 is moved in the longitudinal direction by the conveying unit 22, so the conveying unit 22 of this embodiment moves the sensing unit 27 in the width direction. Without the need to move in a zigzag manner, the sensing unit 27 can be scanned only once in the width direction, and instead, the sensing unit 27 can be moved in the longitudinal direction to scan several times in the longitudinal direction, thereby greatly increasing the inspection time. can be shortened

In addition, as described above, since both sides of the connection barrier 122 are adhered to the barrier 121 on the insulating wall side, the bonding site to be inspected is provided as a pair, and the sensing unit 27 scans both sides of the connection barrier 122 at the same time. Provided as a pair, the transfer unit 22 can quickly complete the inspection by moving the sensing unit 27 only in the longitudinal direction.

As described above, in this embodiment, for the barrier 12 having a composite laminate structure including the metal sheets 121a and 122a and the non-metal sheets 121b and 122b, the eddy current using the sensing unit 27 having a multi-probe By applying the flaw detection, it is possible to accurately identify the adhesion flaw without fear of damage to the barrier 12 .

Of course, the present invention may include a combination of at least any one or more embodiments and known techniques known to those skilled in the art, or a combination of at least two or more embodiments, as additional embodiments, in addition to the embodiments described above.

Although the present invention has been described in detail through specific examples, this is for the purpose of describing the present invention in detail, and the present invention is not limited thereto. It will be clear that the transformation or improvement is possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: liquefied gas storage tank 10: hull
11: Secondary insulation wall 111: Plywood
112: mastic 12: secondary barrier
121: insulating wall side barrier 121a: metal sheet
121b: non-metal sheet 122: connection barrier
122a: metal sheet 122b: non-metal sheet
123: adhesive 13: primary insulation wall
131: plywood
20: liquefied gas storage tank inspection device
21: rubbing unit 22: transfer unit
23: analysis unit 24: sensing unit
241: coil

Claims (6)

An apparatus for forming a storage space for accommodating liquefied gas and inspecting the barrier for a liquefied gas storage tank having an insulating wall and a barrier,
a rubbing part for rubbing the barrier fixed to the heat insulating wall;
a transfer unit for moving the rubbing unit on the barrier; and
and an analysis unit for evaluating the degree of installation of the barrier based on noise or vibration generated during rubbing by the rubbing unit,
The rubbing part,
It is provided in plurality to have different end areas,
Liquefied gas storage tank inspection, characterized in that the rubbing is implemented with the rubbing part having the first size of the end area, and fine rubbing is implemented with the rubbing unit having the end area of the second size smaller than the first size when a defect is identified Device. The method of claim 1, wherein the barrier comprises:
A heat insulating wall-side barrier provided on the heat-insulating wall and a connection barrier for sealing between the heat-insulating wall-side barriers disposed adjacent to each other by being adhered to a plurality of the heat-insulating wall-side barriers disposed adjacent to each other;
The rubbing part,
A liquefied gas storage tank inspection device, characterized in that rubbing a portion adhered to the barrier on the side of the insulating wall in the connection barrier. The method of claim 2, wherein the analysis unit,
A liquefied gas storage tank inspection device, characterized in that it detects an adhesion defect of the barrier based on noise or vibration generated when the air bubbles existing between the connection barrier and the barrier on the side of the insulating wall are pressed by rubbing. According to claim 2, wherein the rubbing portion,
Liquefied gas storage tank inspection device, characterized in that provided in a pair to rub both sides at the same time bonded to the barrier on the insulating wall side in the connection barrier. The method of claim 1,
The rubbing parts having different end areas, liquefied gas storage tank inspection apparatus, characterized in that the replacement while being drawn in, drawn out, or rotated from the transfer unit. According to claim 1, wherein the rubbing portion,
A liquefied gas storage tank inspection device, characterized in that while both the inner tube and the outer tube rub the barrier in the form of a double tube, when a defect is identified, the outer tube rises to implement rubbing only the inner tube.

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