KR100898110B1 - Device for Structural Health Monitoring of Insulation System in LNG Carriers - Google Patents

Abstract

The present invention relates to a device for detecting the abnormality of insulation of LNG carriers, the device for detecting the abnormality of insulation of LNG carriers of the present invention, the membrane metal panel constituting the primary barrier that LNG is in direct contact with the membrane metal panel Load-bearing first plywood, first insulation made of polyurethane foam, triplex forming secondary barrier, second insulation made of polyurethane foam, second plywood, cargo and insulation system In the LNG cargo hold insulation system consisting of a mastic for transmitting the weight of the insulation to the hull, is installed inside the first insulation and / or the second insulation, and selectively detect the damage, strain, temperature change, etc. of the insulation. Characterized in that it comprises a fiber optic sensor to detect the presence or absence in real time.

According to the present invention, since the optical fiber sensor inside the insulation can be detected in real time by detecting damage, strain, temperature change, etc. of the insulation in real time, it is possible to immediately check whether there is an abnormality of the insulation, so that the action can be taken immediately in the event of the insulation, therefore LNG The safety of the carrier can be greatly improved.

LNG Carrier, Insulation Material, Abnormality Detector, Fiber Optic Sensor, LNG Cargo Depot

Description

Device for Structural Health Monitoring of Insulation System in LNG Carriers}

1 is a perspective view of the insulation system of the LNG cargo hold showing the configuration of the first embodiment of the insulation material abnormality detection device of the LNG carrier according to the present invention

Figure 2 is a schematic cross-sectional view of the main part of the insulation system of Figure 1

3 is a perspective view of the insulation system of the LNG cargo hold showing the configuration of the second embodiment of the insulation material abnormality detection device of the LNG carrier according to the present invention.

Figure 4 is a perspective view of the insulation system of the LNG cargo hold showing the configuration of the third embodiment of the insulation material abnormality detection device of the LNG carrier according to the present invention

Figure 5 is a schematic cross-sectional view of the main part of the insulation system of the LNG cargo hold showing the configuration of the fourth embodiment of the insulation material abnormality detection device of the LNG carrier according to the present invention.

Explanation of symbols on the main parts of the drawings

1 metal panel 2 first plywood

3: first heat insulating material 4: triplex

5: 2nd heat insulating material 6: 2nd plywood

7: mastic 8: fiber optic sensor

9: hole

The present invention relates to a device for detecting the abnormality of the insulation of the LNG carrier, and more particularly, to the abnormality such as strain, shock damage, and temperature change according to the dynamic characteristics of the insulation surrounding the cargo hold of the LNG carrier. The present invention relates to a device for detecting abnormality of insulation of LNG carriers that can be accurately and safely detected.

In general, Liquefied Natural Gas (LNG) is a hydrocarbon-based natural gas extracted from the ground, compressed, cooled, and liquefied to -163 ° C for convenience of transportation and storage. Cryogenic liquid reduced to 1/600. The LNG is spotlighted as an alternative to petroleum due to its excellent heat value compared to its price, and the demand for LNG carriers is increasing as LNG trade volume increases as clean energy.

LNG carriers must store -163 ° C liquefied natural gas in super-cold tanks installed on board the ship, so the area around the tank must be protected with special insulation.

However, the insulation of the LNG carriers is exposed to fatigue load conditions in which the LNG carrier fills LNG in the cargo hold for the life of the ship and repeatedly contracts and expands due to the hydraulic load and the heat load. impact load due to sloshing). These repeated fatigue loads and sloshing impact loads cause damage inside the insulation, and the damage inside the insulation is impossible to check in real time during the operation of the ship, so that proper measures could not be taken, thus seriously affecting the safety of the ship. Will be generated.

The present invention has been proposed to solve the above problems, an object of the present invention is to use an optical fiber sensor for the abnormality such as damage of the cargo hold insulation of the LNG carrier, the strain according to the dynamic characteristics, the temperature change due to the insulation damage It is to provide a device for detecting abnormality of insulation of LNG carriers that can be detected safely and accurately in real time.

The present invention for achieving the above object, is installed inside the heat insulating material to form a heat insulation system of the cargo hold for storing LNG, by selectively detecting the damage, strain, temperature change, etc. of the heat insulating material in real time to check the abnormality of the heat insulating material It provides a device for detecting the abnormality of the insulation of the LNG carrier including the optical fiber sensor to detect.

According to one embodiment of the present invention, the membrane metal panel constituting the primary barrier directly contacted by LNG, the first plywood to put a constant load on the membrane metal panel, and the first heat insulating member made of polyurethane foam In the insulation system of LNG cargo hold consisting of a triplex forming a secondary barrier, a second insulation made of polyurethane foam, a second plywood, and a mastic for transferring the weight of the cargo and the insulation system to the hull, And an optical fiber sensor installed inside the first insulation and / or the second insulation to selectively detect damages, strains, temperature changes, etc. of the insulation and to detect abnormality of the insulation in real time. There is provided a device for detecting abnormality of insulation of LNG carriers.

According to the present invention, since the optical fiber sensor inside the insulation can be detected in real time by detecting damage, strain, temperature change, etc. of the insulation in real time, it is possible to immediately check whether there is an abnormality of the insulation, so that the action can be taken immediately in the event of the insulation, therefore LNG The safety of the carrier can be greatly improved.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of the abnormality detection device for the insulation of the LNG carrier according to the present invention will be described in detail.

1 and 2 are perspective views showing a part of the membrane type insulation system of the LNG carrier in which the first embodiment of the insulation abnormality detection device according to the present invention is applied, the insulation system is a direct contact with LNG sequentially from the top 1 A membrane metal panel 1, which is a membrane metal panel constituting the vehicle barrier, a first plywood 2 formed outside the membrane metal panel 1 to apply a constant load to the membrane metal panel 1, The triplex is formed on the outer side of the first plywood 2 and is a triplex formed of polyurethane foam and a triplex formed on the outer side of the first insulator 3 to form a secondary barrier ( 4), a second heat insulator 5 formed on the outside of the triplex 4 and made of polyurethane foam, a second plywood 6 on the outside of the second heat insulator 5, and 2nd plywood (6 It is configured to include a mastic (7) installed on the outside of the ship to transfer the weight of the cargo and insulation system to the hull.

A plurality of optical fiber sensors for selectively detecting the internal damage of the insulation by the impact load or fatigue load and the strain rate, temperature change, etc. of the insulation in real time inside the second insulation (5) and / or the first insulation (3) 8) is installed horizontally.

The optical fiber sensor 8 has various types such as intensity type, interference type, wavelength type, etc. according to the optical application method, but a grid type fiber Bragg grating sensor (FBG: Fiber Bragg Grating sensor) can be said to be developed for structural safety monitoring. ), And an optical fiber Bragg-lattice sensor (FBG) using Wavelength Division Multiplexing (WDM). The optical fiber sensor 8 has a higher sensitivity than the conventional strain gauge that uses an electrical signal, and is not affected by an electromagnetic field because it uses an optical signal, and there is little risk of explosion in reaction with LNG. In addition, since a plurality of sensors can be mounted on one sensor line, it is easy to install, and the small size has the advantage of being able to be installed with minimal impact on the structure.

The detection signal by the optical fiber sensor 8 is transmitted to the controller of the LNG carrier in real time, and the controller determines whether there is an abnormality of the insulation in accordance with the detection signal and notifies the external user when an abnormality occurs.

In this embodiment, the optical fiber sensors 8 are installed so that their axes lie in a direction orthogonal to the mastic 7. However, as shown in the second embodiment in FIG. 3, the optical fiber sensors 8 are inserted horizontally inside the first heat insulator 3 and the second heat insulator 5, with the axes in the same direction as the mastic 7. It may be installed to be placed.

Also, unlike the first and second embodiments described above, a plurality of holes 9 are formed by a tool, such as a drill, in the first heat insulating material 3 and the second heat insulating material 5, as shown in the third embodiment in FIG. ) May be drilled, and a plurality of optical fiber sensors 8 may be installed vertically in these holes 9. In this case, the holes 9 will be filled with the same polyurethane foam or other resin as the insulation after inserting the optical fiber sensors 8.

The optical fiber sensors 8 may be disposed at substantially the same height from lower ends of the first and second heat insulating materials 3 and 5, but may be disposed at different heights.

In addition, the optical fiber sensors 8 may be disposed to be positioned above the mastic 7 or between the mastic 7.

When the optical fiber sensor 8 is installed inside the first and second heat insulating materials 3 and 5 as described above, the optical fiber sensor 8 is installed inside the first and second heat insulating materials 3 and 5 in the following manner. Can be.

First, there is a method in which the optical fiber sensors 8 are fixedly installed in the heat insulating material by fixing the optical fiber sensors 8 at a proper position in the liquid insulating material and then foaming them together with the resin.

Second, there is a method of drilling a hole in the first and second heat insulating materials 3 and 5 by using a tool such as a drill, inserting the optical fiber sensor 8 into the hole, and then filling the hole with resin.

Meanwhile, embodiments of the above-described insulation material abnormality detecting device are configured such that the optical fiber sensor 8 is inserted into the first and second heat insulating materials 3 and 5, but the optical fiber sensor 8 is different from the second heat insulating material 5. ) And the second plywood 6. In this case, the optical fiber sensor 8 is installed on the surface of the second plywood 6 and then installed in such a manner as to be bonded to the polyurethane foam constituting the second insulation 5.

In addition, as shown in the fourth embodiment in FIG. 5, the optical fiber sensor 8 may be inserted into the adhesive 4a of the triplex 4, which is a portion connecting the first and second heat insulating materials 3 and 5. have.

In addition, by installing the optical fiber sensor 8 inside the first and second heat insulating materials 3 and 5 of the heat insulating system in various ways, it is possible to accurately and safely detect the desired information such as damage and / or strain, temperature change of the heat insulating material in real time. will be.

Insulation material abnormality detection device of the LNG carrier according to the present invention, in addition to the above-described embodiment will be possible in various embodiments and modifications within the spirit and scope of the invention defined by the claims of the present invention.

As described above, according to the present invention, by detecting the damage, strain, temperature change, etc. of the heat insulating material in real time by the optical fiber sensor inside the heat insulating material can accurately check whether there is an abnormality of the heat insulating material, it is possible to take immediate action in the event of a heat insulating material. Therefore, gas leakage and large accidents can be prevented and the safety of LNG carriers can be greatly improved.

In particular, the optical fiber sensor constituting the abnormality of the insulating material of the present invention is more sensitive than the conventional strain gauge that uses an electrical signal, and because of the optical signal, it is not affected by the electromagnetic field and risks explosion by reacting with LNG. This virtually no benefit has the advantage of being able to perform stable and accurate sensing functions.

In addition, the optical fiber sensor is easy to install because it can be equipped with a plurality of sensors in one sensor line, the small size has the advantage that can be installed with minimal impact on the structure.

In addition, since the structural safety is ensured by the insulation material abnormality detection device of the present invention as described above, it is easy to design the cargo hold structure of the LNG carrier, there is an effect that can apply a variety of technologies.

Claims (14)

delete A membrane metal panel constituting a primary barrier in which LNG directly contacts, a first heat insulating material provided on the outside of the membrane metal panel, a second heat insulating material provided on the outside of the first heat insulating material, and an outside of the second heat insulating material. In the LNG cargo hold insulation system comprising a mastic installed on the ship to transfer the weight of the cargo and the insulation system to the hull, Including the optical fiber sensor embedded in the first insulation or the second insulation, located in the upper portion of the mastic to selectively detect damage, strain, temperature change, etc. of the heat insulating material in real time to detect the abnormality of the heat insulating material. Detecting abnormality of the insulation material of the LNG carrier, characterized in that configured. 3. The optical fiber sensor of claim 2, wherein the optical fiber sensor comprises any one of a grating type fiber Bragg grating (FBG) or an optical fiber Bragg grating (FBG) using wavelength division multiplexing (WDM). Insulation device abnormality detection device of the LNG carrier, characterized in that configured by applying. delete The apparatus of claim 2, wherein the optical fiber sensor is installed horizontally. The apparatus of claim 5, wherein the optical fiber sensor is disposed in a direction in which the axis thereof is perpendicular to the mastic. 7. [6] The apparatus of claim 5, wherein the optical fiber sensor has a shaft disposed in the same direction as the mastic. The apparatus of claim 2, wherein the optical fiber sensor is installed vertically. delete A membrane metal panel constituting a primary barrier in which LNG directly contacts, a first heat insulating material provided on the outside of the membrane metal panel, a second heat insulating material provided on the outside of the first heat insulating material, and an outside of the second heat insulating material. In the LNG cargo hold insulation system comprising a mastic installed on the ship to transfer the weight of the cargo and the insulation system to the hull, It is embedded in the first heat insulating material or the second heat insulating material, and is located between the mastic and the mastic, and selectively detects the damage, strain, temperature change, etc. of the heat insulating material includes an optical fiber sensor to detect the abnormality of the heat insulating material in real time Insulation material abnormality detection device of the LNG carrier, characterized in that configured to. delete delete delete delete

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