A detection method based on criteria for estimating the location of leaks in a liquefied gas supply pipeline and said liquefied gas supply pipeline.

Abstract

To provide a liquefied gas supply pipeline configuration that allows for reliable estimation of the leak location. [Solution] In a double pipe 1 that contains liquefied gas 5 and forms a vacuum insulation layer, the vacuum insulation layer is divided by a plurality of wall sections 2, and the tip of a suction pipe 30 extending from a vacuum pump 31 and protruding into the double pipe 1, or a suction section 3 near thereto, is positioned at or near the center of each divided area in the longitudinal direction, and one or two measuring sections of vacuum sensors 6 are positioned adjacent to or near the suction section 3, and measuring sections of vacuum sensors 6 are positioned adjacent to or near one or both sides of the wall section 2, thereby estimating the leakage location in the liquefied gas supply pipeline and double pipe 1 through calculations based on the vacuum level of the vacuum sensors 6 and the proportional relationship between the distance between the center position of the suction section 3 and the center position of each vacuum sensor 6.

Description

Technical Field

[0001] The present invention is directed to a liquefied gas supply pipeline that employs a double pipe for vacuum insulation around the liquefied gas, and a detection method based on criteria for estimating the leakage position by the liquefied gas supply pipeline.

Background Art

[0002] The configuration of a pipeline for supplying liquefied natural gas equipped with a double pipe forming a vacuum insulation layer is publicly known.

[0003] In fact, Patent Document 1 discloses the above configuration (paragraphs

[0002] to

[0005] ), and Patent Document 2 also discloses the above configuration (paragraphs

[0013] and

[0031] to

[0033] ).

[0004] When a liquefied gas supply pipeline is used over a long period of time, it is inevitable to avoid a decrease in the vacuum state caused by leakage from the inside due to evaporation of the liquefied gas from the inside and leakage from the outside due to intrusion of outside air into the vacuum insulation layer formed by the double pipe. However, leakage due to outside air tends to occur more frequently than leakage due to evaporation of the liquefied gas.

[0005] However, Patent Documents 1 and 2 do not disclose or suggest any technical idea regarding estimating and detecting each of the above leakage positions, because such estimation and detection are actually quite difficult.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] The present invention aims to provide a configuration for a liquefied gas supply pipeline equipped with a double pipe forming a vacuum insulation layer, which allows for reliable estimation of the location of leakage from both the inside and outside of the vacuum insulation layer. [Means for solving the problem]

[0008] To solve the aforementioned problems, the present invention is based on a liquefied gas supply pipeline with the following basic configurations (1), (2), (3), and (4). (1) A liquefied gas supply pipeline in which a vacuum insulation layer is formed by an inner pipe containing liquefied gas and an outer pipe for blocking the outside air, wherein the vacuum insulation layer is divided by a plurality of wall sections made of insulating material that intersect the longitudinal direction, and a suction section is positioned at or near the center of the longitudinal direction of each divided area, with an opening at the tip of a suction pipe 30 that extends from a vacuum pump installed on the outside of the double pipe and protrudes into the double pipe, and two vacuum sensors are installed on the outside and inside or all the way inside of the double pipe, wherein the measuring section A of the vacuum sensor is positioned adjacent to or near the suction section inside the double pipe, and the measuring section B of the vacuum sensor is positioned adjacent to or near one side wall in each divided area, and each vacuum sensor transmits a signal regarding the degree of vacuum to a measuring instrument installed on the outside of the double pipe, either wired or wirelessly. (2) A double pipe forming a vacuum insulation layer with an inner pipe containing liquefied gas and an outer pipe for blocking the outside air, wherein the vacuum insulation layer is divided by a plurality of wall sections made of insulating material that intersect the longitudinal direction, and a suction section is positioned at or near the center of each divided region in the longitudinal direction, with an opening at the tip of a suction pipe 30 that extends from a vacuum pump installed on the outside of the double pipe and protrudes into the double pipe, and three vacuum sensors are installed on the outside and inside or all the way inside of the double pipe, wherein the measuring section A of the vacuum sensor is positioned adjacent to or near the suction section inside the double pipe, and the measuring sections B1 and B2 of the vacuum sensor are positioned adjacent to or near the side walls in each divided region, and each vacuum sensor transmits a signal regarding the degree of vacuum to a measuring instrument installed on the outside of the double pipe, either wired or wirelessly. (3) A liquefied gas supply pipeline in which a vacuum insulation layer is formed by an inner pipe containing liquefied gas and an outer pipe for blocking the outside air, wherein the vacuum insulation layer is divided by a plurality of wall sections made of insulating material that intersect the longitudinal direction, and a suction section is positioned at or near the center of each divided region in the longitudinal direction, with an opening at the tip of a suction pipe 30 that extends from a vacuum pump installed on the outside of the double pipe and protrudes into the double pipe, and four vacuum sensors are installed on the outside and inside or all the way inside of the double pipe, wherein the measuring sections A1 and A2 of the vacuum sensors are positioned adjacent to or near the suction section inside the double pipe, and the measuring sections B1 and B2 of the vacuum sensors are positioned adjacent to or near the side walls in each divided region, and each vacuum sensor transmits a signal regarding the degree of vacuum to a measuring instrument installed on the outside of the double pipe, either wired or wirelessly. (4) A liquefied gas supply pipeline according to any one of the basic configurations (1), (2), or (3), characterized in that the cross-sectional shape of the double pipe in the wall portion along the longitudinal direction is one of an I-shape perpendicular to the longitudinal direction, an I-shape oblique to the longitudinal direction, or a stepped shape along the longitudinal direction and in a direction perpendicular to the longitudinal direction. [Effects of the Invention]

[0009] In the basic configurations (1), (2), and (3) that employ each of these categories, leakage in the vacuum insulation layer due to evaporation of liquefied gas and intrusion of outside air can be reliably estimated by the operation of a vacuum sensor, with each category as the unit. Furthermore, the inventor's experience has shown that when the leakage location is estimated, the actual leakage location either corresponds to the estimated location or is very close to it, thus confirming that the estimation method enables efficient and reliable detection of the leakage location. However, in order to determine the actual leak location from the estimated leak location, the leak location of the outer pipe must be identified visually at the aforementioned reference location or a location close to it, while the leak location of the inner pipe must be identified using an ultrasonic microscope. Furthermore, since leakage locations are estimated and detected only when no leakage has formed, in almost all cases only one leakage location is detected initially, and it is practically impossible for multiple leakage locations to be detected simultaneously at the beginning. Therefore, in the basic configurations (1), (2), and (3), it is a natural technical assumption that there is only one estimated leakage location.

[0010] In the basic configurations (1), (2), and (3), a total of two, three, and four vacuum sensors are placed in each section area, respectively. Compared to the case where only one vacuum sensor is placed, the actual location can be estimated and detected based on the estimated leak location, and accidents caused by continued leakage can be prevented. The method for calculating the estimated position in the basic configurations (1), (2), and (3) will be described later.

[0011] When a vacuum sensor is installed inside a double pipe and the vacuum sensor is replaced, it is essential to eliminate the vacuum state during the replacement process. However, in the basic configurations (1), (2), and (3), the vacuum state can be eliminated not by eliminating the vacuum state across the entire double pipe, but by eliminating it in each section, thus enabling efficient and economical restoration of the vacuum state.

[0012] In the case of the basic configuration (4), where the cross-sectional shape of the double pipe in the wall section along the longitudinal direction is an I-shape perpendicular to the longitudinal direction, the probability of it being adopted is considerably lower compared to other embodiments because the distance of the connecting insulation material is short. However, because of its simple structure and the limited materials required, it is used to a certain extent. In embodiments other than those described above, in the case of an I-shape that intersects the longitudinal direction at an angle and a stepped shape perpendicular to the longitudinal direction, these shapes are usually adopted because they increase the distance over which heat is conducted from the outside air, thereby reducing the degree of heat conduction and mitigating the influence of the outside air temperature inside the double pipe. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 3(a) is a vertical side cross-sectional view showing the configuration of the basic configuration (1), where (a) is a side cross-sectional view in the longitudinal direction and (b) is a partial side cross-sectional view in a direction perpendicular to the longitudinal direction. The wall portion is shown in the embodiment of Figure 3(a), and the two vacuum sensors are shown installed on both the outside and inside of the pipe. [Figure 2] Figure 3(b) shows a vertical side cross-sectional view of the basic configuration (2), where (a) is a side cross-sectional view in the longitudinal direction and (b) is a partial side cross-sectional view in a direction perpendicular to the longitudinal direction. The wall portion is shown in the embodiment of Figure 3(b), and the three vacuum sensors are shown both installed on the outside and inside of the pipe. [Figure 3]Figure 3(c) shows a vertical side cross-sectional view illustrating the configuration of the basic configuration (3). (a) is a side cross-sectional view in the longitudinal direction, and (b) is a partial side cross-sectional view perpendicular to the longitudinal direction. The wall section is shown as in the embodiment of Figure 3(c). For the sake of explanation, the four vacuum sensors are shown installed entirely inside the double pipe on the left end, while the remaining sensors are shown installed both inside and outside the double pipe. [Figure 4] The following are cross-sectional views along the longitudinal direction illustrating the configuration of the basic configuration (4): (a) shows an I-shape perpendicular to the longitudinal direction, (b) shows an I-shape oblique to the longitudinal direction, and (c) shows a stepped shape forming a direction along the longitudinal direction and a direction perpendicular to the longitudinal direction. [Figure 5] This is a schematic longitudinal diagram illustrating the method for calculating the leakage location, where (a) shows the case of basic configuration (1), (b) shows the case of basic configuration (2), and (c) shows the case of basic configuration (3). Note that the × marks indicate the leakage location estimated by calculation. [Figure 6] This is a vertical cross-sectional view showing the configuration of the embodiment. [Modes for carrying out the invention]

[0014] As shown in FIGS. 1(a) and 1(b), the basic structure (1) is a double pipe 1 that forms a vacuum insulation layer with an inner pipe containing liquefied gas 5 and an outer pipe for blocking outside air. A plurality of heat insulation materials crossing the longitudinal direction are used as wall portions 2 to divide the vacuum insulation layer. A suction pipe 30 extends from a vacuum pump 31 installed outside the double pipe 1 and protrudes into the double pipe 1. A suction portion 3 formed by an opening state at the tip or in the vicinity thereof is arranged at or near the central position in the longitudinal direction of each divided region. On the premise that two vacuum sensors 6 are installed outside and inside or entirely inside the double pipe 1, a measurement portion A of the vacuum sensor 6 is arranged adjacent to or in the vicinity of the suction portion 3 inside the double pipe 1, and a measurement portion B of the vacuum sensor 6 is arranged adjacent to or in the vicinity of one side wall portion in each divided region. With respect to a measuring instrument (not shown) arranged outside the double pipe 1, each vacuum sensor 6 transmits a signal regarding the degree of vacuum in a wired or wireless state. It is a liquefied gas supply pipeline. Although it has a simple structure with the adoption of two vacuum sensors 6, as will be described later in accordance with FIG. 5(a), it is possible to estimate either of the two leakage positions. However, in FIG. 1(a), each vacuum sensor 6 is arranged outside and inside the double pipe 1. Such an arrangement is usually adopted in the normal design, and this point is the same in the basic structures (2) and (3). Furthermore, since the divided regions of each vacuum insulation layer are formed individually, the wall portion 2 usually forms a double structure by the boundary wall portion of adjacent partial regions, and this point is the same in the basic structures (2) and (3). However, regarding the wall portion 2 of the basic structures (1), (2), and (3), a double structure is not an essential requirement, and a single structure can of course be adopted.

[0015] Each vacuum sensor 6 usually operates by a feed-through to the outer pipe of the double pipe 1, that is, a power supply portion, or a battery it has. This point is the same in the basic structures (2) and (3). As for the embodiment using the power supply line 4 as the feed-through, it will be described later as follows.

[0016] In the basic configuration (1), by arranging the suction part 3 at the central position of each section or in its vicinity, a vacuum state can be efficiently and reliably maintained, and this also applies to the basic configurations (2) and (3). Incidentally, although the length of the normal double pipe 1 is often 500 m, the length of the section unit of the basic configuration (1) is often set to 50 m to 100 m with 5 to 10 sections, and this also applies to the basic configurations (2) and (3).

[0017] As shown in FIGS. 2(a) and (b), the basic configuration (2) is a double pipe 1 that forms a vacuum insulation layer by an inner pipe containing liquefied gas 5 and an outer pipe for blocking the outside air. A plurality of heat insulating materials cross the longitudinal direction and the wall part 2 made of the material is used to divide the vacuum insulation layer. The suction pipe 30 extends from the vacuum pump 31 installed outside the double pipe 1 and protrudes into the double pipe 1. The suction part 3 in the open state at the tip or in its vicinity is arranged at the central position of the longitudinal direction of each section area or in its vicinity. On the premise that three vacuum sensors 6 are installed outside and inside the double pipe 1 or all inside, the measuring part A of the vacuum sensor 6 is arranged adjacent or close to the suction part 3 in the double pipe 1, and the measuring parts B1 and B2 of the vacuum sensor 6 are arranged adjacent or close to both side wall parts in each section area. For the measuring instrument (not shown) arranged outside the double pipe 1, each vacuum sensor 6 transmits a signal related to the degree of vacuum in a wired or wireless state. It is a liquefied gas supply pipeline. After arranging the measuring parts B1 and B in the double pipe 1, the measuring parts B1 and B2 are arranged on both sides of the measuring part A of the vacuum sensor 6. According to the magnitude relationship of the degree of vacuum in the measuring parts B1 and B2, it is possible to estimate on which side of the measuring parts B1 and B2 the leakage position exists, and as will be described later in accordance with FIG. 5(b), a specific leakage position can be estimated.

[0018] Basic configuration (3), as shown in Figures 3(a) and (b), is a double pipe 1 in which a vacuum insulation layer is formed by an inner pipe containing liquefied gas 5 and an outer pipe to block the outside air. The vacuum insulation layer is divided by a wall portion 2 made of multiple insulation material that intersects the longitudinal direction. A suction portion 3 is positioned at or near the center of each divided region in the longitudinal direction, with an opening at the tip of a suction pipe 30 that extends from a vacuum pump 31 installed on the outside of the double pipe 1 and protrudes into the double pipe 1. Four vacuum sensors 6 are installed on the outside and inside or all the way inside of the double pipe 1. In this liquefied gas supply pipeline, the measuring units A1 and A2 of the vacuum sensor 6 are positioned adjacent to or in close proximity to the suction unit 3 within the double pipe 1, and the measuring units B1 and B2 of the vacuum sensor 6 are positioned adjacent to or in close proximity to the side walls in each sectioned area, and each vacuum sensor 6 transmits a signal regarding the vacuum level to a measuring instrument (not shown) located outside the double pipe 1, either via wired or wireless means. By positioning the measuring units A1 and A2 of the vacuum sensor 6 adjacent to or in close proximity to the suction pipe 30 leading to the suction unit 3, the leakage condition near the suction unit 3 can be quickly detected. Furthermore, as shown in Figure 3(a), when the measuring portion B1 of the vacuum sensor 6 is in contact with the inner lower surface of the double pipe 1, it is essential that the measuring portion B1 be located near the lower tip surface of the vacuum sensor 6, rather than on the lower tip surface itself.

[0019] The following will be explained with reference to an example. In the basic configurations (1), (2), and (3), embodiments can be adopted in which one or more layers of insulating material are wrapped around the inner pipe of the double pipe 1. In the above embodiment, the degree of thermal energy transferred from the outer pipe to the inner pipe can be mitigated by the wrapped insulating material. In the basic configurations (1), (2), and (3), embodiments can be adopted that feature the formation of an infrared reflective coating on the outer surface of the inner pipe. If infrared radiation irradiates the inner pipe, it cannot be ruled out that there is a risk of the heating caused by such irradiation interfering with the maintenance of the liquid state of the liquefied gas 5 inside the double pipe 1. In the above embodiment, such a problematic condition can be reliably prevented. In the above embodiment, in particular, when the infrared reflective coating is made of a highly conductive metal such as silver, copper, or aluminum, the free electrons efficiently absorb and re-emit infrared energy, thereby efficiently reflecting infrared radiation.

[0020] In the basic configuration (1), as shown in Figure 5(a), the distance from the center of the suction unit 3 to the center of the measurement unit B of the vacuum sensor 6 is defined as L. If the vacuum levels at the measurement units A and B of each vacuum sensor 6 are ab and ab respectively, and b > a, then the leak location can be estimated to be at the following distances x or x' from the center of the suction unit 3. x = a·L / (a+b) x' = a·L / (ba) To explain the basis for x and x' in detail, in Figure 5(a), if a1 ≈ a2 ≠ b, then the leakage location can be estimated to be either on the side where the measuring part B of the vacuum sensor 6 is located, or on the opposite side, with the position of the suction part 3 as the reference point. If the leak location is on the side where the measuring section B of the vacuum sensor 6 is located, the distance x of the center position of the suction section 3 reflects the vacuum degree a of the measuring section A of the vacuum sensor 6 and the distance between the measuring section B of the vacuum sensor 6 and the leak location. Furthermore, since the vacuum degree improves as the distance between the vacuum sensor 6 and the leak location increases, it is possible to assume that the vacuum degree is proportional to the said distance. Therefore, a / x = b / (Lx) holds, and x = a·L / (a+b). This can be derived. In contrast, if the leakage location is on the opposite side from the side where the measuring section B of the vacuum sensor 6 is located, considering the proportional relationship mentioned above, the distance x' from the center position of the suction section 3 is: a / x' = b / (x' + L) holds true. We can derive x' = a·L / (ba).

[0021] In the basic configuration (2), as shown in Figure 5(b), the distance from the center position of the suction section 3 to the center position of the measurement section B2 of the vacuum sensor 6 is defined as L. If the measured values ​​of the vacuum at the measurement sections A, B1, and B2 of each vacuum sensor 6 are a, b1, and b2 respectively, and a ≈ b1 > b2, then the distance x from the center position of the suction section 3 of the vacuum pump 31 to the side where the measurement section B2 is located is estimated to be the leak position. x = a·L / (a+b²) To explain the configuration of x, if b1 > b2, it can be naturally inferred that the measurement is on the B2 side, not the B1 side of the vacuum sensor 6. In this case, x = a·L / (a+b²) can be derived using the same reasoning as for calculating x in the case of basic configuration (1).

[0022] In the basic configuration (3), as shown in Figure 5(c), the distance from the center position of the suction unit 3 to the center position of the measurement unit B2 of the vacuum sensor 6 is defined as L, and when the measured values ​​of the vacuum level of the vacuum sensor 6 at the measurement units A1, A2, B1, B2 of each vacuum sensor 6 are a1, a2, b1, and b2 respectively, and a1 ≈ a2 ≈ b1 > b2, an embodiment can be adopted in which the following distance x from the center position of the vacuum pump 31 is estimated to be the leak position. x = a²·L / (a²+b²)

[0023] The basis for deriving x is the same as in the case of basic configuration (2). However, in the case of basic configuration (2), the measurement section A of the vacuum sensor 6 is not necessarily located on the side of the measurement section B2 of the vacuum sensor 6, whereas in the case of basic configuration (3), the vacuum degree a2 of the measurement section A2 of the vacuum sensor 6, which is closer to the measurement section B2 of the vacuum sensor 6, can be used, thus enabling the securing of a measurement value with slightly higher accuracy than the x value in basic configuration (2).

[0024] As is clear from the above specific calculations, in basic configuration (1), the leak location can be estimated based on the measured values ​​of measurement sections A and B of each vacuum sensor 6; in basic configuration (2), the leak location can be estimated based on the measured values ​​of the vacuum level at measurement sections A, B1, and B2 of each vacuum sensor 6; and in basic configuration (3), the leak location can be estimated based on the measured values ​​of the vacuum level at measurement sections A1, A2, B1, and B2 of each vacuum sensor 6.

[0025] In the basic configurations (1), (2), and (3), if iron is used for the inner and / or outer pipes, hydrogen molecules contained in the iron will flow out from the iron wall 2. However, in the case of a typical vacuum pump 31, the ability to both draw in and discharge hydrogen is extremely limited.

[0026] In such cases, the aforementioned problems can be avoided by adopting an embodiment that features the separate placement of a vacuum pump 31 for hydrogen exhaust.

[0027] If the leak in the double pipe 1 is on the inside, it is due to the gas being liquefied; if the leak is on the outside, it is mainly due to nitrogen and oxygen, which are the main components of air.

[0028] In such cases, if the vacuum sensor 6 of the basic configuration (1), (2), and (3) is equipped with a discrimination device that determines the type of leaking gas by measuring the mass per unit volume, it is possible to quickly determine whether the leak location is inside or outside.

[0029] In the basic configurations (1), (2), and (3), embodiments can be adopted in which, in the double pipe 1, plastic is used for the outer pipe, metal is used for the inner pipe, and a vapor-deposited coating of aluminum, zinc, or tin is applied to the inner wall of the outer pipe and / or the outer wall of the inner pipe.

[0030] In the above embodiment, by using plastic as the outer pipe, the degree of heat conduction from the outside air is reduced, while by using metal for the inner pipe, resistance to the pressure that would otherwise cause expansion due to the vaporization of the liquefied gas 5 can be maintained. Furthermore, the rationale for coating the inner wall of the outer pipe and / or the outer wall of the inner pipe with a vapor-deposited film of aluminum, zinc, or tin is to reflect the radiant heat accumulated in the plastic inner pipe and prevent it from being transmitted to the region of liquefied gas 5.

[0031] In particular, when stainless steel is used as the metal, an extremely desirable embodiment can be realized due to its strength and low thermal conductivity. Incidentally, the thermal conductivity of stainless steel is 15 (W / m·K).

[0032] When a curve is formed in a pipeline pipe, it is unavoidable that the frequency of leakage will be higher compared to the case of a straight pipe due to contact with the liquefied gas 5 flowing inside the inner pipe, which involves flow resistance.

[0033] In the basic configurations (1), (2), and (3), in the embodiment characterized by setting the width of the horizontal direction perpendicular to the longitudinal direction of the divided area to be wider in the region where a curve is formed in the pipeline compared to the straight region, the drawback that leakage tends to occur more frequently in the case of curves can be reduced by decreasing the flow velocity of the liquefied gas 5 in the curved region.

[0034] In the basic configurations (1), (2), and (3), an embodiment can be adopted in which power is supplied to the measurement section of the vacuum pump 31 and / or vacuum sensor 6 by the power supply line 4, as shown in Figures 1, 2, and 3.

[0035] When power is supplied by the power supply line 4, the vacuum pump 31 and / or vacuum sensor 6 must be operated by batteries. However, since the vacuum pump 31 and vacuum sensor 6 are usually in constant operation, batteries must be replaced at predetermined intervals, whereas in the above embodiment, such replacement is unnecessary.

[0036] In the embodiment employing the power supply line 4, when supplying liquefied gas 5 on land, solar power generation can be employed, and when supplying liquefied gas 5 at sea, offshore power generation can be employed.

[0037] In such embodiments, it is possible to achieve both the use of natural energy and the stable operation of the vacuum pump 31 and / or vacuum sensor 6.

[0038] In the basic configurations (1), (2), and (3), embodiments can be adopted that feature a flat bottom surface when the pipeline pipes are installed on land.

[0039] In this embodiment, the double pipe 1 can be supported and maintained in a stable state relative to the ground. In particular, in cases where wind pressure on the pipeline is high, such as in deserts, stable support and maintenance can prevent or reduce damage to the double pipe 1.

[0040] In the basic configurations (1), (2), and (3), embodiments can be adopted in which the liquefied gas supply pipeline pipes are buried underground at a depth of 3m or more from the surface.

[0041] In the above embodiment, even when there are large temperature fluctuations on the ground, the ambient temperature around the double pipe 1 can be kept stable.

[0042] While it is certainly possible to use plastic as the material for all of the double pipe 1, in the basic configurations (1), (2), and (3), embodiments can be adopted that are characterized in that epoxy resin, polyamide-imide resin, or polyetherimide resin is used as the material for the double pipe 1. Furthermore, since the gas release rate from the surface of plastic materials is greater than that of metals, it is preferable to coat the surface with metal.

[0043] These polymers all have low thermal conductivity and a high flexural modulus, which allows for the creation of a robust and stable double pipe 1. Incidentally, the thermal conductivity of epoxy resin is 0.04-0.05 (W / m·K) and its flexural modulus is 1760-3160, the thermal conductivity of polyamide-imide is 0.008 (W / m·K) and its flexural modulus is 5000, and the thermal conductivity of polyether-imide is 0.006 (W / m·K) and its flexural modulus is 3300.

[0044] In the basic configurations (1), (2), and (3), embodiments can be adopted in which transparent plastic is used as the material for the double pipe 1.

[0045] In this embodiment, when the degree of leakage detected by the vacuum sensor 6 exceeds a predetermined level, the location of the leak can be quickly estimated by visual inspection or the use of a magnifying glass, and then detected at the estimated location or a location near it, which is extremely convenient. [Examples]

[0046] The embodiment is characterized by employing a triple pipe 1+1', which has an additional vacuum layer by setting an outer pipe 1' on the outside of the double pipe 1, as shown in Figure 7.

[0047] In the above embodiment, even if leakage occurs in the double pipe 1, the triple pipe 1+1' formed further on the outside can maintain an extremely stable vacuum insulation state. In particular, when using the triple pipe 1+1' in water such as the sea, lakes, or rivers, a stable supply of liquefied gas 5 can be achieved by reliably preventing water intrusion. In this case, it is preferable that the outermost pipe 1' of the triple pipe 1+1' is made of a plastic material with good corrosion resistance to water and seawater. [Industrial applicability]

[0048] Based on the basic configurations (1), (2), and (3), the present invention has immense utility in that it can reliably and quickly estimate the leakage state for each divided area, thereby preventing accidents caused by leakage. [Explanation of Symbols]

[0049] 1 Double pipe 1' A pipe set even further outside the double pipe. 1+1' Triple Pipe 2 wall 30 Suction pipe extending from the vacuum pump and protruding within a double pipe 31 Vacuum pump 3 Suction part 4 Power supply lines 5. Liquefied gas 6. Vacuum Sensor

Claims

1. A liquefied gas supply pipeline is provided in which a vacuum insulation layer is formed by an inner pipe containing liquefied gas and an outer pipe that blocks the outside air, the vacuum insulation layer is divided by a wall section made of multiple insulating materials that intersects the longitudinal direction, and a suction section is positioned at or near the center of each divided region in the longitudinal direction, with an opening at the tip of a suction pipe that extends from a vacuum pump installed on the outside of the double pipe and protrudes into the double pipe, and two vacuum sensors are installed on the outside and inside or all the way inside of the double pipe, with the measuring section A of the vacuum sensor positioned adjacent to or near the suction section inside the double pipe, and the measuring section B of the vacuum sensor positioned adjacent to or near one side wall in each divided region, and each vacuum sensor transmits a signal regarding the degree of vacuum to a measuring instrument installed on the outside of the double pipe, either wired or wirelessly.

2. In a double-walled pipe forming a vacuum insulation layer with an inner pipe containing liquefied gas and an outer pipe to block the outside air, the vacuum insulation layer is divided by walls made of multiple insulating materials intersecting the longitudinal direction, and a suction section, which is an open state at the tip or near the tip of a suction pipe extending from a vacuum pump installed on the outside of the double-walled pipe and protruding into the double-walled pipe, is positioned at or near the center of the longitudinal direction of each divided area, and three vacuum sensors are installed on the outside and inside or entirely inside of the double-walled pipe, with the measurement section A of the vacuum sensor positioned adjacent to or in close proximity to the suction section inside the double-walled pipe, and the measurement section B of the vacuum sensor １ and B ２ A liquefied gas supply pipeline in which vacuum sensors are positioned adjacent to or in close proximity to the side walls of each sectioned area, and each vacuum sensor transmits signals related to the vacuum level to a measuring instrument located on the outside of the double pipe, either via wired or wireless means.

3. In a double pipe that forms a vacuum insulation layer with an inner pipe containing liquefied gas and an outer pipe that seals off the outside air, the vacuum insulation layer is divided by a wall made of multiple insulating materials that intersect the longitudinal direction, and a suction section is positioned at or near the center of each divided region in the longitudinal direction, with an opening at the tip of a suction pipe that extends from a vacuum pump installed on the outside of the double pipe and protrudes into the double pipe, and four vacuum sensors are installed on the outside and inside or all the way inside of the double pipe, and the measurement section A of the vacuum sensor is assumed to be １ , A ２ The vacuum sensor is positioned within the double pipe, adjacent to or in close proximity to the suction section, and the vacuum sensor measurement section B １ and B ２ A liquefied gas supply pipeline in which vacuum sensors are positioned adjacent to or in close proximity to the side walls of each sectioned area, and each vacuum sensor transmits signals related to the vacuum level to a measuring instrument located on the outside of the double pipe, either via wired or wireless means.

4. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that the cross-sectional shape of the double pipe in the wall portion along the longitudinal direction is one of an I-shape perpendicular to the longitudinal direction, an I-shape oblique to the longitudinal direction, or a stepped shape along the longitudinal direction and in a direction perpendicular to the longitudinal direction.

5. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that one or more layers of insulating material are wrapped around the inner pipe.

6. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that an infrared reflective coating is formed on the outer surface of the inner pipe.

7. The liquefied gas supply pipeline according to claim 6, characterized in that silver, copper, or aluminum is used as the infrared reflective coating.

8. The liquefied gas supply pipeline according to claim 1, characterized in that, L is the distance from the center position of the suction section to the center position of the vacuum sensor's measuring section B, and when the measured values ​​of the vacuum degree at measuring sections A and B of each vacuum sensor are a and b, respectively, and b > a, the position at which the leak location is estimated to be the distance x from the center position of the suction section toward the side where the measuring section B is located, or the distance x' toward the side opposite to the side where the measuring section B is located. x=a・L / (a+b) x'=a・L / (ba-a)

9. From the central position of the suction part to the measurement part B of the vacuum sensor ２ With the distance to the central position of the measurement part B of each vacuum sensor being L, the measurement parts A and B of each vacuum sensor １ , B ２ The measured values of the degree of vacuum at are a and b respectively １ , b ２ And a ≒ b １ > b ２ In the case of, the position of the distance x from the central position of the suction part to the side where the following measurement part B ２ exists is estimated as the leakage position. The liquefied gas supply pipeline according to claim 2, characterized in that x=a・L / (a+b ２ )

10. Measurement section B of the vacuum sensor, from the center position of the suction section. ２ Let L be the distance to the center position of each vacuum sensor. １ , A ２ , B １ , B ２ The measured values ​​of the vacuum level in each location are a １ , a ２ , b １ , b ２ and a １ ≒a ２ ≒b １ >b ２ In this case, the measurement section B below is measured from the center position of the suction section. ２ The liquefied gas supply pipeline according to claim 3, characterized in that the location at a distance x from the side where the leak exists is estimated as the leak location. x=a ２ ・L / (a ２ +b ２ )

11. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that, when iron is used as the material for the inner pipe and / or outer pipe, a vacuum pump for hydrogen exhaust is separately provided.

12. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that it is equipped with a discrimination device that determines the type of gas leaking from the vacuum sensor by measuring the mass per unit volume.

13. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that the outer pipe is made of plastic with a vapor-deposited coating of aluminum, zinc, or tin on its inner surface, and the inner pipe is made of metal.

14. The liquefied gas supply pipeline according to claim 11, characterized in that stainless steel is used as the metal.

15. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that, in the region of the double pipe where a curve is formed, the width in the horizontal direction perpendicular to the longitudinal direction of the divided region is set wider than that of the straight region.

16. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that power is supplied to each vacuum pump and / or each vacuum sensor by a power supply line.

17. The liquefied gas supply pipeline according to claim 16, characterized in that solar power generation is employed when supplying liquefied gas on land, and offshore power generation is employed when supplying liquefied gas at sea.

18. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that the bottom surface is flat when the double pipe is installed on land.

19. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that a double pipe is buried underground at a depth of 3 meters or more above ground level.

20. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that epoxy resin, polyamide-imide resin, or polyetherimide resin is used as the material for the double pipe.

21. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that transparent plastic is used as the material for the double pipe.

22. A liquefied gas supply pipeline according to any one of claims 1, 2, or 3, characterized in that it employs a triple pipe in which a vacuum layer is further provided on the outside of a double pipe.

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