Vacuum insulated piping unit for liquefied gas and method for detecting damage to vacuum insulated piping for liquefied gas

Abstract

To detect damage of a pipe appropriately and reliably with a simple structure, regarding a vacuum heat insulating pipe for liquefied gas.SOLUTION: A pipe unit (1) for transferring liquefied gas has an inner pipe (7) through which the liquefied gas passes, and an outer pipe (9) that covers the inner pipe. A vacuum heat insulating pipe (5) in which a vacuum layer (11) is formed between the inner pipe (7) and the outer pipe, is provided with an inner pipe pressure measurement device (13) that measures a pressure in the inner pipe (7), an outer pipe pressure relief device (15) provided in the outer pipe (9), and a gas detection device (17) that detects the type of gas released from the outer tube pressure relief device (15).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vacuum insulated piping unit for liquefied gas and a method for detecting damage to a vacuum insulated piping for liquefied gas. [Background technology]

[0002] Conventionally, it has been proposed to use a double-structure vacuum insulated pipe as a pipe for transferring liquefied gas such as liquefied natural gas or liquefied hydrogen, for example, between a liquefied gas carrier and a tank on land (see, for example, Patent Document 1). This insulated pipe has a structure in which an outer pipe covers an inner pipe with a vacuum layer in between, so that high insulation properties are obtained and the temperature rise of the low-temperature liquefied gas flowing inside the inner pipe can be effectively suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-004382 A Summary of the Invention [Problem to be solved by the invention]

[0004] For piping used to transport liquefied gas, it is important to find any damage that may cause gas leakage as soon as possible. However, in the case of the above-mentioned double-structure piping, it is difficult to visually check whether the inner pipe is damaged. It is also possible to detect damage to the inner pipe by installing a measuring device such as a vacuum gauge on the outer pipe, but this is not preferable because it leads to a complex piping structure and an increase in weight.

[0005] In order to solve the above problems, an object of the present invention is to provide a vacuum insulated pipe for liquefied gas that can detect breakage in a timely and reliable manner with a simple structure. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a vacuum insulated piping unit for liquefied gas, comprising: A piping unit for transporting liquefied gas, comprising: a vacuum insulation pipe including an inner pipe through which the liquefied gas passes and an outer pipe covering the inner pipe via a vacuum layer; an inner pipe pressure measuring device for measuring a pressure in the inner pipe; an outer pipe pressure relief valve provided in the outer pipe; a gas detection device for detecting the type of gas released from the outer tube pressure relief valve; Equipped with.

[0007] In addition, the liquefied gas storage tank unit according to the present invention comprises: A tank for storing liquefied gas; A piping unit that is attached to the tank and transfers the liquefied gas between the tank and the outside, the liquefied gas vacuum insulation piping unit described above; It is equipped with:

[0008] The method for detecting damage to a vacuum insulated pipe for liquefied gas according to the present invention comprises the steps of: A method for detecting the occurrence of damage to a vacuum insulated pipe for transporting a liquefied gas, the method comprising: an inner pipe through which the liquefied gas passes; an outer pipe covering the inner pipe; and a vacuum layer formed between the inner pipe and the outer pipe, the method comprising the steps of: monitoring the pressure in the inner pipe by an inner pipe pressure measuring device that measures the pressure in the inner pipe; When an abnormal change in the value measured by the inner pipe pressure measuring device is detected, monitoring whether or not an outer pipe pressure relief device provided in the outer pipe is activated within a predetermined time range; When the outer tube pressure relief device is activated, detecting the release of the detection target gas by a gas detection device; determining whether or not the inner pipe is broken or whether or not the outer pipe is broken based on the measurement value of the inner pipe pressure measuring device and whether or not the gas detection device emits the target gas; Includes.

[0009] With these configurations, in a piping having a double vacuum structure, by measuring the pressure inside the inner pipe, it is possible to detect a state in which there is a high possibility of the outer pipe pressure relief valve actually operating before that valve actually operates. Furthermore, by combining this with detection of the type of gas released from the outer pipe pressure relief valve, piping damage can be detected timely and reliably with a simple structure. Effect of the Invention

[0010] As described above, according to the present invention, damage to a vacuum insulated pipe for liquefied gas can be detected timely and reliably with a simple structure. [Brief description of the drawings]

[0011] [Figure 1] 1 is a side view showing a schematic configuration of a vacuum thermal insulation pipe for liquefied gas according to one embodiment of the present invention and a liquefied gas storage tank unit including the same. FIG. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing the vacuum thermal insulation pipe for liquefied gas of FIG. [Diagram 3] 3 is a cross-sectional view showing a schematic state in which damage occurs to an inner pipe in the piping of FIG. 2. FIG. [Figure 4] 3 is a cross-sectional view showing a schematic state in which damage occurs to an outer pipe in the piping of FIG. 2. FIG. [Diagram 5] FIG. 2 is a flow diagram showing a method for detecting breakage in a pipe according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a vacuum insulated piping unit for liquefied gas (hereinafter, simply referred to as a "piping unit") 1 according to one embodiment of the present invention and a liquefied gas storage tank unit (hereinafter, simply referred to as a "tank unit") 3 including the piping unit 1. The piping unit 1 is used for transferring liquefied gas. The piping unit 1 includes a vacuum insulated piping (hereinafter, simply referred to as a "piping") 5 having a double-pipe structure. That is, as shown in FIG. 2, the piping 5 includes an inner pipe 7 through which liquefied gas passes and an outer pipe 9 that covers the inner pipe 7. A vacuum layer 11 is formed in the radial gap between the inner pipe 7 and the outer pipe 9. The piping unit 1 further includes an inner pipe pressure measuring device 13 that measures the pressure in the inner pipe 7, an outer pipe pressure relief device 15 provided in the outer pipe 9, and a gas detection device 17 that detects the type of gas released from the outer pipe pressure relief device 15.

[0013] As shown in Fig. 1, the tank unit 3 includes a tank 19 that stores liquefied gas, and the above-mentioned piping unit 1 attached to the tank 19. Liquefied gas is transferred between the tank 19 and its outside, for example, a liquefied gas storage base 21 on land, via piping 5 of the piping unit 1. The tank unit 3 is installed on a ship 23, for example, a liquefied gas carrier. However, the tank unit 3 may be installed on land.

[0014] The liquefied gas stored in the tank 19 and transferred through the piping 5 is, for example, liquefied petroleum gas (LPG, about -45°C), liquefied ethylene gas (LEG, about -100°C), liquefied natural gas (LNG, about -160°C), liquefied hydrogen (LH2, about -250°C), or liquefied helium (LHe, about -270°C). In this embodiment, liquefied hydrogen is stored in the tank 19 and transferred through the piping 5.

[0015] In this embodiment, the tank 19 is configured as a double-shell tank having an inner tank and an outer tank. For example, a vacuum insulation layer is formed between the inner tank and the outer tank. However, the configuration of the tank 19 is not limited to this example. For example, the tank 19 may be one in which a powder insulation material such as perlite, which is a granular insulation material, is filled in the vacuum insulation layer. The tank 19 may also be a single-shell tank covered with insulation material. In this case, the insulation material may be, for example, composed of multiple vacuum insulation panels or multiple foam panels.

[0016] Specifically, in this embodiment, the tank 19 has a main body 19a which is a portion for storing liquefied gas, and a dome portion 19b which protrudes upward from the main body 19a. The piping 5 of the piping unit 1 is attached to the dome portion 19b. Although only one piping unit 1 is shown in the figure for simplification, a plurality of piping units 1 may be provided in one tank 19. The piping 5 is extended from inside the main body 19a through the dome portion 19b to the outside of the tank 19. In this embodiment, the portion of the piping 5 which is extended to the outside of the dome portion 19b is configured as a vacuum double pipe which will be specifically described below.

[0017] In this embodiment, as shown in Fig. 2, the piping 5 is formed by connecting a plurality of split pipes 5a in the length direction. Specifically, as shown in Fig. 2, each split pipe 5a is provided at both ends with partition walls 25 that close the vacuum layer 11 between the outer pipe 9 and the inner pipe 7. Also, gate valves 27 are provided near both ends of the inner pipe 7 of each split pipe 5a. By configuring the piping 5 by combining split pipes 5a having such a structure, the installation work of the piping 5 is facilitated, and the vacuum degree of the vacuum layer 11 is easily maintained and controlled.

[0018] In this embodiment, an outer pipe pressure relief valve, more specifically, a seal-off valve, is used as the outer pipe pressure relief device 15. The seal-off valve, which is the outer pipe pressure relief device 15, has a cylindrical valve body 31 protruding from the outer circumferential surface of the outer pipe 9, and a disk-shaped valve body (not shown) fitted into the inner circumferential portion of the valve body 31. An O-ring is attached to the outer circumferential surface of the valve body. In this example, an outer pipe pressure relief device 15 is provided for each divided pipe body 5a.

[0019] In the outer pipe pressure relief device 15 configured as a seal-off valve of this embodiment, the valve body is normally pressed against the valve body 31 by the vacuum pressure of the vacuum layer 11. In a state where the inside of the outer pipe 9 is under positive pressure due to damage to the pipe 5 or the like, the fixing of the valve body to the valve body 31 is maintained only by the frictional force between the inner peripheral surface of the valve body 31 and the O-ring. That is, in the outer pipe pressure relief device 15, when the pressure in the vacuum layer 11 is less than a predetermined set operating value, the gas release port 37 of the valve body 31 is blocked by the valve body. On the other hand, when the pressure in the vacuum layer 11 exceeds the set operating value, the valve body is separated from the inner peripheral part of the valve body 31 by the pressure, and the gas in the pipe 5 is released from the gas release port 37. The set operating value of the outer pipe pressure relief device 15 is a value sufficiently smaller than the design pressure resistance value of the outer pipe 9 (for example, about 1 / 100 to 1 / 10 of the design pressure resistance value of the outer pipe 9). When the pipe 5 is installed, a vacuum pump is connected to the gas discharge port 37 , and the inside of the outer pipe 9 is evacuated via the gas discharge port 37 .

[0020] The outer pipe pressure relief device 15 is not limited to the seal-off valve described above, and any device may be used as long as it has the function of releasing gas at a predetermined set operating value. However, by using an outer pipe pressure relief valve such as a seal-off valve for the outer pipe 9 inside which the vacuum layer 11 is formed, the structure of the piping unit 1 can be simplified.

[0021] 2, the inner pipe 7 is provided with an inner pipe pressure relief device (in this example, an inner pipe pressure relief valve) 39. In the example shown, a pressure relief passage 41 branching off from the inner pipe 7 is provided, and the inner pipe pressure relief device 39 is provided on this pressure relief passage 41. As the inner pipe pressure relief device 39, for example, a spring-type safety valve is used.

[0022] In this embodiment, a gas detection tape that changes color when it comes into contact with a detection target gas (hydrogen gas in this embodiment) is used as the gas detection device 17. The gas detection tape is attached to the gas release port 37 of the outer tube pressure relief device 15.

[0023] Next, a method for detecting the occurrence of damage to the pipe 5 in the thus configured piping unit 1 shown in FIG. 2 will be described.

[0024] First, a phenomenon that occurs when breakage occurs in the inner pipe 7 or the outer pipe 9, which is a premise of the breakage detection method for the pipe 5, will be described. In the following description, as an example, it is assumed that the loading and unloading operation from the liquefied gas tank 19 via the pipe 5 has been completed and the on-off valve between the tank 19 and the pipe 5 is closed (i.e., the liquefied gas is not flowing in the pipe 5 and the liquefied gas is stored in the pipe 5). In the following description, the gas stored in the tank 19 and transferred by the pipe 5, which is the subject of gas leakage detection in the breakage detection method, may be referred to as the "detection target gas". The detection target gas may be in a liquid phase, a gas phase, or a mixed phase thereof.

[0025] First, in a normal state where neither the inner pipe 7 nor the outer pipe 9 is damaged, the temperature inside the inner pipe 7 gradually rises due to heat input from the outside to the piping 5, and the pressure inside the inner pipe 7 rises continuously and gently. However, since the piping 5 is configured as a vacuum insulated piping 5 as described above, the pressure rise in the inner pipe 7 in the normal state progresses at an extremely slow speed.

[0026] If a relatively large break occurs in the inner tube 7 from this normal state as shown in Figure 4, the target gas G to be detected will leak from the break into the vacuum layer 11 inside the outer tube 9, and the pressure inside the inner tube 7 will rapidly drop due to the pressure difference between the inner tube 7 and the vacuum layer 11.

[0027] When the detection target gas G leaks into the vacuum layer 11, the heat insulating performance of the vacuum layer 11 is reduced, and the temperature of the detection target gas G increases and vaporization proceeds due to heat input from the outside. This causes the pressure in the inner tube 7, which had once decreased, to increase. As the pressure in the inner tube 7 increases, the detection target gas G leaks further into the outer tube 9, and the pressure in the outer tube 9 also increases.

[0028] On the other hand, when a minute break occurs in the inner tube 7, the pressure inside the inner tube 7 gradually decreases due to leakage of the detection target gas G from the inner tube 7 at the beginning of the break. After that, the internal pressure of the inner tube 7 gradually increases due to a decrease in the insulation performance of the vacuum layer 11. Furthermore, the temperature of the inner tube 7 increases due to the decrease in the insulation performance of the vacuum layer 11, so that the detection target gas G leaked into the vacuum layer 11 expands, and the pressure inside the outer tube 9 increases.

[0029] When the pressure inside the outer tube 9 reaches the set operating value of the outer tube pressure relief device 15, the outer tube pressure relief device 15 is activated and releases the detection target gas G. At this time, the gas detection device (gas detection tape) 17 attached to the gas release port 37 of the outer tube pressure relief device 15 reacts to the detection target gas G and changes color, becoming capable of detecting the release of the detection target gas G.

[0030] Next, a phenomenon that occurs when the outer tube 9 is damaged and the liquefied gas leaks from the outer tube 9 will be described.

[0031] 5, when the outer tube 9 is damaged and air A flows into the vacuum layer 11 from the outside, the heat insulating performance of the vacuum layer 11 is reduced, and the temperature of the detection target gas G increases and vaporizes due to the heat input from the outside in the inner tube 7. This causes the pressure in the inner tube 7 to rise rapidly.

[0032] When the damage to the outer tube 9 is minor and the amount of air A flowing from the outside into the vacuum layer 11 is small, the air A that has flowed into the vacuum layer 11 is cooled by the low-temperature inner tube 7 and condenses as liquefied air A on the surface of the inner tube 7. As more air A subsequently flows in, the temperature of the surface of the inner tube 7 and inside the vacuum chamber rises, and the air A that was once liquefied vaporizes. This inflow of air A from the outside and vaporization of the liquefied air A causes the pressure in the vacuum layer 11, i.e., inside the outer tube 9, to rise.

[0033] When the pressure inside the outer tube 9 reaches the set operating value of the outer tube pressure relief device 15, the outer tube pressure relief device 15 is activated and releases air A. At this time, the gas detection tape attached to the gas release port 37 of the outer tube pressure relief device 15 does not react to air A, and is in a state where it can detect that the target gas G has not been released.

[0034] If the damage to the outer pipe 9 is severe and a large amount of air A flows into the vacuum layer 11 from the outside at the time of the damage, a significant drop in the vacuum level and a rise in the temperature of the inner pipe 7 will cause a rapid and significant increase in pressure in the inner pipe 7, but the pressure in the outer pipe 9 may not reach the set operating value of the outer pipe pressure relief device 15. In this case, only the inner pipe pressure relief device 39 will operate, and the outer pipe pressure relief device 15 will not operate.

[0035] Since the above-mentioned phenomenon occurs when damage occurs in the inner pipe 7 or the outer pipe 9, as shown in Figure 6, the method for detecting damage to piping 5 in this embodiment includes monitoring the pressure inside the inner pipe 7 using the inner pipe pressure measuring device 13 (inner pipe internal pressure monitoring step S1), monitoring whether the outer pipe pressure relief device 15 is operating within a predetermined time range when an abnormal change in the measurement value by the inner pipe pressure measuring device 13 is detected (outer pipe pressure relief device operation monitoring step S2), detecting the release of the detection target gas using the gas detection device 17 when the outer pipe pressure relief device 15 is activated (target gas release detection step S3), and determining whether damage has occurred in the inner pipe 7 or the outer pipe 9 based on the measurement value of the inner pipe pressure measuring device 13 and the type of released gas detected by the gas detection device 17 (damage occurrence determination step S4).

[0036] In this specification, the "peculiar change" in the measurement value by the inner pipe pressure measuring device 13 refers to a change behavior different from the continuous slow increase in the inner pipe 7 pressure in the normal state described above. Specifically, the above-mentioned rapid change (decrease) in the inner pipe 7 pressure when a relatively large break occurs in the inner pipe 7, the gradual decrease in the inner pipe 7 pressure when a small break occurs in the inner pipe 7, and the rapid change (increase) in the inner pipe 7 pressure when a break occurs in the outer pipe 9 are typical examples of the "peculiar change".

[0037] Specifically, if a decrease in the measured value (a rapid decrease or a gradual decrease) is detected in the inner pipe internal pressure monitoring step S1, and then, if it is confirmed that the outer pipe pressure relief device 15 has been activated in the outer pipe pressure relief device operation monitoring step S2, a step S3 is performed to detect the release of the detection target gas G (in this example, hydrogen gas) using the gas detection device 17 (in this example, a gas detection tape attached to the gas outlet 37 of the outer pipe pressure relief device 15), and then, a determination is made in damage occurrence determination step S4 that damage has occurred in the inner pipe 7.

[0038] On the other hand, if a rapid increase in the measured value is detected in the inner pipe internal pressure monitoring step S1, and then, if it is confirmed in the outer pipe pressure relief device operation monitoring step S2 that the outer pipe pressure relief device 15 has been activated, it is determined in the damage occurrence determination step S4 that damage has occurred in the outer pipe 9 by confirming, using the gas detection instrument 17, that the target gas G to be detected has not been released.

[0039] In the inner pipe pressure monitoring step S1, what kind of behavior of pressure change is detected as "peculiar" (for example, what rate of pressure drop or pressure rise is "gentle" or "rapid") is appropriately set by prior experimentation or calculation depending on the type of gas G to be detected, the size of the pipe 5, the size of the tank 19, the amount of stored gas, etc. In the outer pipe pressure relief device operation monitoring step S2, the time range within which the presence or absence of valve operation is monitored is also appropriately set by prior experimentation or calculation.

[0040] In addition, even if the inner pipe 7 is damaged and an unusual change (a rapid or gradual drop in this example) occurs in the pressure inside the inner pipe 7, the pressure inside the outer pipe 9 may not rise sufficiently and the outer pipe pressure relief device 15 may not operate. For example, such a phenomenon is likely to occur when the damage caused to the inner pipe is small. In order to deal with such a situation, a step of supplying the detection target gas G from outside into the inner pipe 7 (detection target gas supply step S5) may be added when the operation of the outer pipe pressure relief device 15 is not confirmed within a predetermined time range in the outer pipe pressure relief device operation monitoring step S2 after the detection target gas G supply step is performed again through the outer pipe pressure relief device operation monitoring step S2, and if the release of the detection target gas G is detected by the gas detection instrument, it is determined that the inner pipe 7 is damaged.

[0041] In addition, regardless of whether or not there is an unusual change in the pressure inside the inner tube 7, the target gas G to be detected may be supplied into the inner tube 7 from the outside if operation of the outer tube pressure relief device 15 is not confirmed within a predetermined time range.

[0042] Specifically, the supply of the detection target gas G can be performed, for example, by cooling down the ship during loading and unloading operations. In addition, in a large liquefied gas carrier equipped with a cooling down facility, gas may be supplied using the cooling down facility even while the ship is in operation.

[0043] On the other hand, as described above, when the degree of damage to the outer pipe 9 is large, a rapid and large pressure rise occurs in the inner pipe 7, while the pressure in the outer pipe 9 does not reach the set operating value of the outer pipe pressure relief device 15, and the outer pipe pressure relief device 15 does not operate. To deal with such a situation, after detecting a rapid rise in the measurement value of the inner pipe pressure measuring device 13 in the inner pipe internal pressure monitoring step S1, if the operation of the outer pipe pressure relief device 15 is not confirmed in the outer pipe pressure relief device operation monitoring step S2, a step of monitoring the operation of the inner pipe pressure relief device 39 (inner pipe pressure relief device operation monitoring step S6) may be added. In that case, if the operation of the inner pipe pressure relief device 39 is confirmed, it is determined that damage has occurred in the outer pipe 9.

[0044] The detection of the release of the target gas G in the target gas release detection step S3 may be performed by a gas detection device 17 other than the gas detection tape attached to the gas release port 37 of the outer pipe pressure relief device 15. For example, the manager of the piping 5 may bring a portable gas detector to the gas release port 37 and directly measure the gas to detect the release of the target gas G.

[0045] In addition, if a drop in internal pressure is detected in the inner pipe internal pressure monitoring step S1 but no release of the target gas G is detected in the target gas release detection step S3, other causes such as leakage from the gate valve 27 of the inner pipe 7 are suspected rather than damage to the inner pipe 7, so inspection of related parts such as the gate valve 27 is performed.

[0046] According to the vacuum insulated piping unit 1 for liquefied gas, storage tank unit, and breakage detection method of this embodiment described above, in a piping 5 having a vacuum double structure, by measuring the pressure inside the inner pipe 7, it is possible to detect a state in which there is a high possibility of the outer pipe pressure relief device 15 actually operating before that device actually operates.Furthermore, since this is combined with detection of the type of gas released from the outer pipe pressure relief device 15, it is possible to timely and reliably detect the occurrence of breakage in the piping 5 with a simple structure.

[0047] Although the preferred embodiment of the present invention has been described above with reference to the drawings, various additions, modifications, and deletions can be made without departing from the spirit of the present invention. Therefore, such additions, modifications, and deletions are also included in the scope of the present invention. [Explanation of symbols]

[0048] 1 Piping unit 3 Liquefied gas storage tank unit 5 Vacuum insulated piping 7 Inner tube 9 Outer tube 11 Vacuum layer 13 Inner pipe pressure measuring device 15 Outer pipe pressure relief valve 17 Gas detection equipment 19. Tank

Claims

1. A method for detecting the occurrence of damage to a vacuum insulated pipe for transporting a liquefied gas, the method comprising: an inner pipe through which the liquefied gas passes; an outer pipe covering the inner pipe; and a vacuum layer formed between the inner pipe and the outer pipe, the method comprising the steps of: monitoring the pressure in the inner pipe by an inner pipe pressure measuring device that measures the pressure in the inner pipe; When an abnormal change in the value measured by the inner pipe pressure measuring device is detected, monitoring whether or not an outer pipe pressure relief device provided in the outer pipe is activated within a predetermined time range; When the outer tube pressure relief device is activated, detecting the release of the detection target gas by a gas detection device; determining whether or not the inner pipe is broken or whether or not the outer pipe is broken based on the measurement value of the inner pipe pressure measuring device and whether or not the gas detection device emits the target gas; A method for detecting damage to a vacuum insulated pipe for liquefied gas, comprising:

2. 10. The method of claim 1 , In monitoring the inner pipe pressure, detecting a drop in the value measured by the inner pipe pressure measuring device, which is the peculiar change; After detecting a decrease in the measurement value of the inner pipe pressure measuring device, monitoring whether the outer pipe pressure relief device is activated within a predetermined time range; When the outer pipe pressure relief device is activated, detecting the emission of the detection target gas by the gas detection device, thereby determining whether the inner pipe has been damaged; A method for detecting damage to a vacuum insulated pipe for liquefied gas, comprising:

3. 3. The method of claim 2, supplying the detection target gas from outside into the inner pipe when the outer pipe pressure relief device does not operate within a predetermined time range after detecting a decrease in the measurement value of the inner pipe pressure measuring device; After supplying the detection target gas into the inner pipe, monitoring whether or not the outer pipe pressure relief device is activated within a predetermined time range; When the outer pipe pressure relief device is activated, detecting the emission of the detection target gas by the gas detection device, thereby determining whether the inner pipe has been damaged; A method for detecting damage to a vacuum insulated pipe for liquefied gas, comprising:

4. 10. The method of claim 1 , In monitoring the pressure inside the inner pipe, detecting a rapid increase, which is the peculiar change, of the value measured by the inner pipe pressure measuring device; monitoring whether the outer pipe pressure relief device is activated within a predetermined time range after detecting a rapid increase in the measurement value of the inner pipe pressure measuring device; When the outer tube pressure relief device is activated, determining whether or not the outer tube has been damaged by confirming that the gas detection device has not emitted the target gas; A method for detecting damage to a vacuum insulated pipe for liquefied gas, comprising:

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