KR20110049485A - Cargo tanks of liquefied gas carriers and its supporting structures - Google Patents

Abstract

PURPOSE: A cargo tank and a supporting device for a liquefied gas carrier are provided to reduce design and production costs by minimizing the quantity and dimension of supporting devices. CONSTITUTION: A cargo tank for a liquefied gas carrier comprises an independent tank(20), a horizontal movement preventing apparatus, and a vertical movement preventing apparatus(26). The independent tank is placed on a double base(2) of a hold(4). The horizontal movement preventing apparatus supports the load of the independent tank and controls the horizontal movement of the independent tank. The vertical movement preventing apparatus controls the vertical movement of the independent tank.

Description

Storage tank and supporting device for liquefied gas carrier {CARGO TANKS OF LIQUEFIED GAS CARRIERS AND ITS SUPPORTING STRUCTURES}

Storage tank and supporting device for liquefied gas line

The present invention provides a support for a low temperature liquefied gas carrier for transporting liquefied gas, a low temperature pressure liquefied gas carrier and a pressure liquefied gas carrier (hereinafter referred to as "liquefied gas carrier") and a liquefied gas storage tank 20 mounted on the carrier. It is about the structure and its arrangement.

Examples of loads and efficient arrangement of support devices that act on the support structure of the existing liquefied gas storage tank 9 are known from Korean Patent No. 10-1994-0001911, Japanese Patent No. 1995156860, and US Patent No. 5531178.

One embodiment of the existing liquefied gas carrier is shown in FIG. The existing liquefied gas carrier ship is provided with a box-shaped independent liquefied gas tank 9 (hereinafter referred to as "tank") on the hull 1. A plurality of transverse bulkheads 3 are provided which extend in the width direction of the hull along the longitudinal direction of the hull 1 in order to define the hold 4 for the carrier to accommodate the tanks 9.

The supporting device of the tank 9 of the existing liquefied gas carrier ship is a vertical support device 7 for supporting the load in the vertical direction, as shown in Figure 2, the double bottom of the hull for restraining the movement in the width direction of the hull ( 2) Install the lower lateral movement preventing device 13 and the upper lateral movement preventing device 15 installed between the upper deck 5 and the tank 9, respectively, which are installed on the upper side, and the tank when the hold 4 is flooded. (9) is composed of a floating prevention device (17) for preventing floating and damage, and a paper moving prevention device (8) for preventing a load and movement in the longitudinal direction.

In the existing low temperature liquefied gas carrier ship, as shown in Figs. 1 and 2, the lower lateral movement preventing device 13 and the upper lateral movement preventing device 15 have the width of the hull 1 to restrain the movement in the width direction of the hull. Installed in the direction center line, the load of the tank 9 is a structure for supporting the vertical support devices 7 are installed on the tank 9 and the upper portion of the double bottom (2). In addition, the paper movement preventing device (8) for limiting the longitudinal movement is installed on the tank (9) and the double bottom (2). Accordingly, as illustrated in FIG. 3, a plurality of paper moving prevention devices 8, a lower horizontal movement preventing device 13, and a vertical support device 7 must be disposed at the intersections of all vertical girders and the horizontal members, and the lower horizontal The reinforcement of the double bottom 2 supporting the movement preventing device 13 and the vertical support devices 7 is required, and these devices 7, 13 are used for the hull type due to the load of the tank and the dynamic load of the waves. Since the directional stresses are applied simultaneously, suitable reinforcement is applied to the vertical load supporting device 7 and the lower transverse movement preventing device 13 and the double bottom girders 12a, 12b, 12c, 12d near the bottom of these devices 7, 13. In addition, a girder 12c for reinforcing the lower portion of the vertical load supporting device 7 supporting near the end of the tank 9 is adjacent to the hopper tank girder 12d. Installation of these girders 12c and 12d is difficult because they must be arranged and the hopper girders 12d are not supported by the support of the tank 9. Did not apply is to be arranged in a less efficient. In particular, as the front hold of the hull 4 is reduced in the width direction of the hull due to the linear effect, the double bottom girders are additionally arranged in the lower part of the hull to support the vertical support device 7, so that a large number of the There is a point that the airlift and the inspection is difficult during operation, it is therefore necessary to remove the vertical support device (7) installed on the double bottom (2). In addition, the upper lateral movement preventing devices 15a, 15b, and 15c provided between the upper plate portion 5 of the hull and the upper plate portion of the tank 9 are damaged due to a small gap between the contact portions 15a and 15c and the cause of friction. Cases are often reported, so arrangements are needed without the upper lateral displacement preventive devices 15a, 15b, 15c installed.

In addition, tanks used for low pressure or pressure liquefied gas lines are either pressure cylindrical (IMO Type C) or bi-lobe type (IMO Type C) with two cylinders. Shaped tanks are less efficient in terms of volume utilization than box-shaped tanks, for example, in the case of low-temperature pressure carbon dioxide carriers, cylindrical tanks are used, which are not yet used as stand-alone liquefied gas tanks, which is subject to size limitations. . Therefore, if the box-type independent low-temperature tank type 20 is used, a low-temperature pressure-type carbon dioxide carrier can be larger than the carbon dioxide carrier having a capacity of about 20,000 m3. However, the box-type independent low-temperature tank has a higher probability of leaking low-temperature liquid than the cylindrical or bi-lobe box-type low-pressure tank because the outer shell and internal reinforcement are manufactured by welding. If so, the probability of damage to the hold 4 and tank 9 is relatively high. Therefore, when a high pressure low temperature liquefied gas flows out of the tank 9 due to a defect in a welded part or an abnormality of a pressure regulating device, a system for detecting an existing leak of liquefied gas and preventing explosion (eg, dry nitrogen system, It is difficult for the hull 1 and the tank 9 to be protected by the gas leakage alarm system alone.

Accordingly, an object of the present invention is to improve the volumetric efficiency of the tank 20, to minimize the number and dimensions of the support device to reduce the design and production costs, and to provide a support device for easy inspection of the tank 20 It is to provide a stand-alone liquefied gas carrier ship and a method of supporting the tank. In addition, when the box-shaped independent low temperature or low temperature pressure type or pressure liquefied gas tank 20 is applied, when the low temperature liquid leaks due to damage of the tank 20, the hull 1 and the tank ( 20) to provide a means for preventing damage.

Paper copper is installed on the double bottom (2) of the hull in order to remove the vertical support device (7) installed on the upper double bottom used in the existing carrier and the transverse movement preventing device (15) installed on the tank top. The prevention device 8 and the lateral movement preventing device 13 also support the load of the tank, and remove the lateral movement preventing device 15 installed on the existing tank 20, and the double bottom of the hull and the hopper tank ( Multiple support devices are to be installed on top of the hopper tank and transverse bulkhead tank. In addition, an explosion prevention hatch is installed on the upper deck of the hull to prevent damage to the tank and the hull when a low temperature liquid leaks, and a drip tray is provided between the tank and the upper part of the double bottom, and the hull member constituting the hold. Low temperature steel is applied.

As an effect of the present invention, the devices 28, 29 and 30 for supporting most of the tanks for supporting the tank 20 are located near the neutral axis of the hull so that they are less stressed due to the longitudinal strength, or the transverse bulkhead tank 23 As it is not stressed by the longitudinal strength above, there is less interaction due to the movement of the hull and the load of the tank, so that the size and weight can be reduced compared to the existing supporting devices (7, 8, 13, 15). Is alleviated.

As another effect of the present invention as shown in Figs. 6 and 7, the composite support devices 26 and 27 that support the load of the tank 20 and serve as the longitudinal movement prevention and the lateral movement prevention are arranged. Thus, the number of supporting devices installed in the case of installing the transverse movement preventing devices 13 and 15, the longitudinal movement preventing device 8 and the vertical load supporting device 7 of the existing carriers illustrated in FIG. This reduces the weight of the ship and increases productivity.

In addition, the support devices 26, 27, 28, 29, 30 located under the tank 20 always have a uniform compressive stress, thereby effectively using the support devices. Therefore, some of the vertical support device (7) found in the support device of the existing tank (2) does not take the compression load, eliminating the disadvantage that the original function is not fully exhibited.

Figure 8 shows the effect of the present invention, the existing carrier ship as shown in Figure 3 arranged the lateral movement preventing device, vertical support devices at the intersection with the girders (12a, 12b, 12c) and the transverse member, In the present invention, as illustrated in FIG. 8, the transverse movement preventing device 27 is disposed at the center line of the double bottom 2, and the paper movement preventing device 26 is disposed near the center of the hold 4. Since the composite support devices 28, 29, 30 are disposed only in the hopper tank 24 and the transverse bulkhead tank 23, the number of support devices can be greatly reduced. In addition, ships with existing arrangements will have an additional girder 12c next to the longitudinal girders 12d supporting the hopper structure such that the members are placed in the vicinity of the hopper tank 24 to increase the weight and the structure is increased. Although complicated, the present invention eliminates the need for such an additional girder 12c since the composite support devices 29 and 30 are arranged above the hopper tank 24. In particular, in the case of the tank 9 installed at the front hold 4 of the existing carrier, the width of the double bottom 2 due to the linearity of the hull is reduced, so that a large number of longitudinal girders are formed at the bottom of the tank 9. Although the present invention is arranged, the support structure is located in the center of the tank 20 and the side of the hull, no need for additional longitudinal girders and vertical support device (7) even if the linear change is reduced the weight of the hull and thus the drying cost Enables a reduction of

According to the support device for the independent storage tank used for the liquefied gas carrier according to the present invention, since the support devices (28, 30) to prevent the lateral movement, there is no need for the left and right movement prevention device 15 on the tank 20 For this reason, calculations for the design and adjustment of the transverse movement preventing device 15 disposed between the upper tank 9 and the upper deck 5 of the existing carrier can be omitted. Therefore, the production cost and labor can be saved. In addition, as compared with the upper lateral movement preventing device 15 disposed in the upper portion of the tank (9) used in the existing vessel, the possibility of damage occurring inside the hull can be reduced, and the necessary maintenance inspection is omitted. In addition, by eliminating the interaction between the upper portion of the tank 20 and the inner upper portion of the hold 4, the safety operability of the carrier ship is improved.

In addition, the existing paper movement preventing device 8 mainly disposed below the dividing bulkhead 18 of the tank is designed for preventing longitudinal movement only as illustrated in FIG. 4, so that the vertical support device near the device 8 ( 7) is subjected to a load from the dividing bulkhead 18 of the tank 9, so that an increase in dimensions is required. However, in the present invention, since the paper moving prevention device 26 receives not only the longitudinal movement but also the vertical load, the paper moving prevention device 26 efficiently supports the load from the dividing bulkhead 18.

Table 1 shows the effect per unit of the present invention when applied to the existing 80,000 m3 large liquefied gas carriers, and when the size of the carrier is enlarged, it can be expected to have a larger effect.

Item Effects of the Invention Weld field reduction due to removal of upper lateral displacement preventive device (15), m 400 m Weight saving due to reduction of upper lateral movement preventing device (15), ton 40 tons
Weld field reduction due to reduction of vertical load supporting device (7), m 280 m
Weight saving due to reduction of vertical load supporting device (7), ton 210 tons Reduction of weld field due to removal of double bottom longitudinal girder (12c) near hopper tank bottom, m 400 m
Weight saving due to the removal of longitudinal barrel girder (12c), ton 80 tons

Therefore, the present invention has the advantages of lightening the weight of the hull, reducing the drying cost, reducing the number of the supporting structure, the supporting structure is simple, easy to inspect, and the liquefied gas from the tank due to the accident It protects tanks and hulls when spilled and improves safety and can be applied to the development of large-capacity, box-type independent low temperature liquefied gas carriers or low pressure pressure liquefied gas carriers.

There may be a plurality of embodiments of the present invention, and exemplary embodiments will be described in detail with reference to the accompanying drawings. Through this embodiment, it is possible to better understand the objects, features and advantages of the present invention.

There may be a plurality of embodiments of the present invention, and the present invention will be described in detail with reference to the accompanying drawings. Through this embodiment, it is possible to better understand the objects, features and advantages of the present invention.

6 and 7, the tank 20 is independently supported on the double bottom 2, the hopper tank 24, and the transverse bulkhead tank 23, and the tank 20 is approximately a box. Shape and the lower end portion of the tank 20 is a stepped structure. Compound support devices (26, 28) for limiting the load support and longitudinal movement of the tank 20 of the liquefied gas carrier ship is installed on the upper portion of the double bottom (2) and the transverse bulkhead tank (23), the tank (20) Compound support devices 27 and 29 for limiting load support and transverse movement are installed on top of double bottom 2 and on top of hopper tank 24. In addition, to limit the movement in the longitudinal and transverse direction of the tank 20 to the end portion of the tank 20, and to support the load of the tank 20 on the upper side of the transverse bulkhead tank 23 and the hopper tank 24 In addition, the composite support device 30 is installed.

The longitudinal movement preventing device 26 is composed of paper movement preventing devices 26a, 26b, 26c, and 26d as shown in FIG. They are located in the center of the approximately hold 4 of the tank 20, and mainly located below the water-repellent bulkhead 18 of the tank 20, so that the member 26b and the member 26d move in the longitudinal direction of the tank 20. The longitudinal movement of the member 26c attached to the 20 is limited. In addition, as illustrated in FIG. 9, the load of the tank 20 is efficiently transmitted to the double bottom 2 of the hull through the members 26c and 26a and 26e. Therefore, one support device effectively serves to support the load from the tank 20 and to limit the longitudinal movement. In addition, the pads 26d and 26e are made of a heat insulating material, and serve to block heat from the tank 2. The pad 26d has a slight gap between the member 26c and the member 26b and serves to absorb some movement of the tank. The member 26b is attached to the double bottom 2 to serve the double bottom 2 structure in the longitudinal load transmitted from the tank 20. The member 26c is attached to the tank 20 and serves to transfer the load of the tank to the members 26a and 26b.

The transverse movement preventing device 27 is constituted by the transverse movement preventing devices 27a, 27b, 27c, and 27d as shown in FIG. These restrict the movement of the member 27b and the member 27c to which the member 27d is attached to the tank 20 during the lateral movement of the tank 20. In addition, the load of the tank 20 is efficiently transmitted to the double bottom 2 through the member 27a, the member 27c, and the member 27e. Therefore, one support device effectively serves to support the load from the tank 20 and to limit the transverse movement. In addition, the pads 27d and 27e are made of a heat insulating material to serve to block heat from the tank 20. The pad 27d has a slight gap between the member 27c and the member 27b and serves to absorb some movement of the tank 20. The member 27b is attached to the double bottom 2 to serve the double bottom 2 structure in the lateral load transmitted from the tank 20. The member 27c is attached to the tank 20 and serves to transfer the load of the tank to the members 27a and 27b.

In order to support the load of the tank 20 and limit the movement in the longitudinal direction, the composite support device 28 on the top of the transverse bulkhead tank 23 installed in the transverse bulkhead 3 located on the front and rear of the hold 4 illustrated in FIG. 11. ) To further support the load of the tank 20, to prevent longitudinal movement, and to expand and contract due to thermal deformation of the tank 20. This longitudinal movement preventing device 28 is composed of paper movement preventing devices 28a, 28b, 28c, 28d and 28e, as shown in FIG. Since the member 28a is placed on the upper side of the transverse bulkhead tank 23 which is a lateral strength member, the longitudinal strength stress generated during the movement of the hull is not acted on, so that the weight can be reduced. This member 28a also limits the movement of the member 28f attached to the tank 20 and the thermal expansion and contraction of the tank 20 due to the longitudinal motion of the hull. The member 28e is placed on the pad 28d to allow the tank 20 to contract and expand while supporting the tank load in the longitudinal direction. The pads 28c and 28d also use materials (eg pigment plywood, thermal barrier ceramics, etc.) to block heat from the tank 20. The bracket 28b serves to prevent the movement of the composite member 28a. A slight gap is maintained between the pad 28c and the member 28f attached to the tank 20 to allow the tank 20 to contract and expand.

In order to support the load of the tank 20 and limit the transverse movement of the tank 20, the composite support device 29 is installed on the hopper tank 24 located on the side of the hull illustrated in FIG. 20) to support the load, to prevent transverse movement and to expand and contract due to thermal deformation of the tank (20). 12 shows the elements constituting the composite support device 29. Since the member 29a is placed on the upper hopper tank 24 near the neutral axis of the hull, the longitudinal strength stress generated during the movement of the hull acts less, making it lighter than the vertical support device 7 applied to the existing ship. The member 29a also restricts the movement of the member 29f attached to the tank 20 and the thermal expansion and contraction of the tank 20 due to the lateral movement of the hull. The member 29e is placed on the member 29d to support the load of the tank 20 so that the member 29e can move in the lateral direction so that the tank 20 can contract and expand. Therefore, the upper lateral movement preventing device 15 illustrated in FIG. 2 used in the existing ship is not required. The pads 29c and 29d also use materials (eg, pigment plywood, thermal barrier ceramics, etc.) to block heat from the tank 20. Bracket (29b) serves to prevent the movement of the compound support device (29a). A slight gap is maintained between the pad 29c and the member 29f attached to the tank 20 to allow the tank 20 to contract and expand.

FIG. 13 shows a composite support device 30a that prevents longitudinal and lateral movement of the lower corner portion of the tank 20 and supports the load of the tank 20. Although omitted from FIG. 13, various members 28c, 28e, 28f, 29c, 29e, and 29f which are previously described between the tank 20 and the composite support device 30a to facilitate the contraction and expansion of the tank 20 and Similar members are installed in the tank 20 and the member 30a, and a slight gap is maintained between the tank 20 and the member 30a to facilitate the contraction and expansion of the tank 20. Brackets 30b and 30c serve to attach to the transverse bulkhead 3 and the hull side plate 10 of the composite member 30a. The composite support device 30a similarly attaches the heat shielding material used on the pads 28c, 28d, 29c, 29d to block heat from the tank 20, similarly to the members 28a, 29a.

In the case of the low temperature pressure liquefied gas line, when the liquefied gas flows out of the tank 20 due to a welding defect or an abnormality of the pressure regulating device, the explosion occurs when the liquefied gas leaks between the tank 20 and the hold 4. By providing an explosion prevention hatch 21 on the upper deck 5 of the upper hold 4 of the tank 2, the explosion prevention hatch 21 operates when a certain amount of gas and pressure are reached. The hull 1 and the tank 20 can be protected. For example, the optimum transport rate of liquefied carbon dioxide is -55 degrees Celsius and the pressure at that time is about 6.5 bar. If the high pressure carbon dioxide is leaked due to a defect in the tank 20, the hold (4) When the damage of the structural members constituting the) reaches the expected pressure, several explosion-proof hatches 21 are opened to relieve the pressure to prevent explosion of the entire tank 20 and damage to the hull 1. do.

On the other hand, when the low pressure liquefied gas flows out to the hold 4, when the low temperature liquid gradually fills between the hold 4 and the tank 20, damage to the hold 4 due to the low temperature liquid may occur. Therefore, according to the amount of low temperature liquefied gas leaked out and the temperature of the hold 4, an appropriate low temperature steel material (low temperature steel, aluminum alloy steel, stainless steel, nickel steel, Invar steel, etc.) may be hull adjacent to the tank 20 in the hold 4. Applies to members. In addition, several drip trays 22 are installed between the tank 20 and the double bottom 2 for temporary storage and evaporation of the liquid flowing out of the tank 20 so that the liquid flowing out of the tank 20 is kept cool. To be stored in the drip tray (22) along the gap between the (11) and the tank (20). Prevents damage to the hold (4),

The arrangement of the support device and the tank 20 described above may be applied to not only a carrier having a double hull, but also a carrier having a single hull, and a support device (7, 8, 13, 15) applied to a conventional carrier. Can also be used mixed with.

Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive, and those skilled in the art without departing from the gist of the present invention claimed in the appended claims Anyone can make various modifications, as well as the meaning and scope of the claims, and all changes or modifications derived from the equivalent concept should be construed as being included in the scope of the present invention.

1 is a side view of a stand-alone tank support device installed in the hold of a conventional carrier.

2 is a front view of a stand-alone tank support device installed in the hold of a conventional carrier

3 is a plan view of a support device in a hull double bottom under a standalone tank installed at a hold of a conventional carrier.

4 is a detailed side view of the members constituting the paper moving prevention device 8 installed between the double bottom top of the conventional carrier and the independent tank.

5 is a detailed front view of the members constituting the lateral movement preventing device 15 installed between the upper plate of the conventional carrier and the independent tank.

6 is a side view of a carrier according to an embodiment of the present invention.

7 is a front view of a transport ship according to an embodiment of the present invention.

8 is a plan view of the supporting device on the hull double bottom, hopper tank (24), transverse bulkhead tank (23) installed below the independent tank of the carrier in accordance with an embodiment of the present invention.

FIG. 9 is a detailed side view of the members constituting the paper moving prevention device 26 installed between the upper end of the double bottom and the independent tank according to the embodiment of the present invention.

10 is a detailed front view of the members constituting the lateral movement preventing device 27 installed between the upper end of the double bottom (2) and the independent tank 20 according to an embodiment of the present invention.

FIG. 11 is a detailed side view of the members constituting the longitudinal movement preventing device 28 disposed on the transverse bulkhead tank 23 according to the embodiment of the present invention.

12 is a detailed front view of the members constituting the lateral movement preventing device 29 disposed on the hopper tank 24 according to the embodiment of the present invention.

Figure 13 is a three-dimensional view of the members constituting the device (30) to simultaneously play the role of preventing longitudinal movement and transverse movement of the lower end of the tank 20 according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1: hull 2: double bottom

3: transverse bulkhead 4: hold

5; Deck 6: Tank Dome

7: vertical support device 8: longitudinal movement preventing device

9: cargo tank 10: side shell

11: Tank coolant 12a, 12b, 12c, 12d: Double girder

13: Lower transverse movement prevention device 14: Hopper inclined plate

15: upper transverse movement preventing device 16: upper inclined plate

17: tank injury prevention device 18: water jet bulkhead

20: cargo tank 21: explosion-proof hatch

22: drip tray 23: transverse bulkhead tank

24: hopper tank 25a, 25b, 25c: double bottom girder

26: double bottom longitudinal movement preventing device 27: double bottom horizontal movement preventing device

28: transverse bulkhead tank longitudinal movement prevention device 29: hopper tank lateral movement prevention device

30: longitudinal and transverse movement preventing device

Claims (5)

The horizontal tank accommodates the independent tank 20 mounted on the double bottom 2 of the hold 4 in an independent state, and supports the load of the tank 20 and restrains the movement of the tank 20 in the width direction. Movement preventing devices 27 and 29 and front and rear movement preventing devices 26 and 28 for suppressing the movement of the tank 20 in the longitudinal direction, and the composite support device which simultaneously suppresses the longitudinal movement and the lateral movement. Liquefaction is provided with a double bottom (2) for supporting the 30 and the hopper tank 24 and the transverse bulkhead tank (23) having a flat top, and the liquefied gas explosion prevention hatch (21), drip tray (22), etc. Gas carrier. The liquefied gas carrier ship according to claim 1, wherein the independent tank (20) has a rectangular box shape as a whole and the lower end of the tank (20) has a stepped shape. The device of claim 1, wherein the lateral movement preventing devices 27, 29, and 30 are installed on the upper portion of the double bottom 2 and the hopper tank 24 under the tank 20, and the longitudinal movement preventing device. (26, 28, 30) is a support device for an independent storage tank of a liquefied gas carrier ship, characterized in that the tank is installed on the upper bottom of the double bottom (2) and the transverse bulkhead tank (23). 2. The tank (20) of claim 1, further comprising an explosion-proof hatch (21) on the upper deck (5) of the hull to prevent damage due to explosion of the hold (4) and the tank (20). Liquefaction characterized in that the low temperature steel is used for the hull members constituting the holding (4) adjacent to and the plurality of drip trays 22 between the double bottom (2) and the lower portion of the tank (20). Gas carrier. The method of claim 1, wherein all or a portion of the support devices 26, 27, 28, 29, 30 are mixed with the support devices (7, 8, 13, 15) used in the existing carrier. Liquefied gas carrier ship characterized in that the installation.

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