KR20120035671A - Anti-sloshing apparatus - Google Patents

Abstract

PURPOSE: A sloshing reduction device is provided to prevent damage to a cargo space by suppressing sloshing regardless of the amount of liquid gas stored in a cargo space. CONSTITUTION: A sloshing reduction device comprises a pillar(110) and a surface flow reducing unit(130). The pillar is installed vertically in the cargo space of a membrane type liquefied gas carrier. The surface flow reducing unit is installed to slide along the longitudinal direction of the pillar and has lower specific gravity than the specific gravity of liquid gas. The surface flow reducing unit comprises hubs and a plurality of blades. The hub is installed in the pillar to be slidable. The blade is installed in the hub in the radial direction.

Description

Sloshing Reduction Means {ANTI-SLOSHING APPARATUS}

The present invention relates to sloshing reducing means, and more particularly to sloshing reducing means for reducing the sloshing phenomenon of the liquefied gas stored in the cargo hold of the liquefied natural gas carrier.

Natural gas and petroleum gas, which are widely used as fuels, are transported in a liquefied gas state in which the volume is reduced through liquefaction for efficient transport.

For example, liquefying natural gas to liquefied natural gas (Liquefied Natural Gas, LNG) reduces its volume to about one-sixth, increasing the amount it can carry at one time. The liquefied natural gas carried to the destination is then regasified and used as fuel.

In order to transport such liquefied gas over a long distance, a liquefied gas carrier equipped with a cargo tank capable of storing cryogenic liquids is used. Liquefied gas carriers are largely classified into independent tank type with hull and independent cargo hold according to the way of cargo hold and membrane type which forms the barrier with metallic membrane to block the outflow of liquefied gas.

It is known that more than half of the liquefied gas carriers currently used are membrane systems.

1 is a cross-sectional view of the membrane-type liquefied gas carrier ship.

Referring to Figure 1, the cargo hold 20 is provided in the hull 10 of the membrane-type liquefied gas carrier (1).

The hull 10 may have a double hull structure formed by the outer hull 11 and the inner hull 12, the cargo hold 20 is a membrane 21 and the outside to prevent the outflow of liquefied gas (not shown) It can be composed of a heat insulating structure 22 for suppressing the transfer of heat to the liquefied gas.

In addition, the cargo tower 20 may be provided with a pump tower 30 for the inflow and discharge of liquefied gas.

The cargo hold 20 of the membrane-type liquefied gas carrier 1 is likely to be damaged by a sloshing phenomenon due to the flow of the liquefied gas stored therein. That is, when the liquefied gas carrier ship 1 is shaken by the influence of waves and wind, the shake is transferred to the liquefied gas stored in the cargo hold 20, a sloshing phenomenon occurs.

The sloshing phenomenon occurs more seriously as the free surface area of liquefied gas is wider. Therefore, when the liquefied gas carrier is fully loaded, a small amount of liquefied gas can be used as fuel for the propulsion engine after unloading the liquefied gas. It is a trend that causes even more problems during the collinear operation with only liquefied gas loaded.

When a sloshing phenomenon occurs, a large pressure is partially applied to the membrane 21, or the cargo hold 20 may be damaged by an impact force that liquefied gas collides with. Even if the cargo hold 20 is partially damaged, if a liquefied gas is leaked to the outside through this portion, a large accident may occur, and research and development for suppressing sloshing phenomenon have been steadily progressing.

Embodiments of the present invention are to suppress the occurrence of the sloshing phenomenon by suppressing the flow phenomenon generated in the liquid level of the liquefied gas regardless of the amount of liquefied gas stored in the cargo hold.

According to an aspect of the present invention, a support formed in the cargo hold of the membrane-type liquefied gas carrier ship to form a barrier of the liquefied gas with a metal membrane, and is installed to be slidably movable along the longitudinal direction of the liquefied gas than the liquefied gas And a surface flow reduction means having a small specific gravity, wherein the surface flow reduction means includes a hub slidably movable in the support and a plurality of blades radially installed in the hub. Can be.

The sloshing reducing means may further include an upper fixing part for fixing the upper end of the support to the hull of the liquefied gas carrier, and a lower support part supporting the lower end of the support so as to be able to flow to the hull.

Here, the upper fixing portion, through the hull and is coupled to the hull and the hollow portion is a hollow cylinder-shaped sleeve coupled to the upper end of the support, and the membrane is penetrated by the support and is disposed on the outer peripheral surface of the support and the It may further include a first sealing plate coupled to the membrane to seal between the post and the membrane.

In this case, the sleeve may be welded to the hull, the upper end of the support is welded to the sleeve, the first sealing plate may be welded to the outer peripheral surface of the support and the membrane.

The lower support part includes a housing having a receiving part configured to receive a lower end of the support in one side, a housing supporter coupled to the hull inner surface and interposed between the hull and the housing to support the housing, and the housing. The second sealing plate may further include a second sealing plate disposed in a portion through which the membrane is penetrated and coupled to the outer circumferential surface of the housing and the membrane to seal the gap between the housing and the membrane.

In this case, the housing supporter may be welded to the inner surface of the hull, and the second sealing plate may be welded to the outer circumferential surface of the housing and the membrane.

The sloshing reducing means may further include an upper stopper and a lower stopper coupled to the upper side and the lower side of the support to limit the slideable range of the hub.

The cross section of the blade may have a shape of any one of elliptical, streamlined or semicircular. The lower portion of the blade may have at least one protrusion protruding downward. In addition, the blade may be formed in a wider vertical width of the intermediate region than both ends. In addition, the blade may be formed in the hollow along the longitudinal direction.

The embodiment of the present invention can prevent the cargo hold from being damaged by suppressing the sloshing phenomenon from occurring regardless of the amount of the liquefied gas stored in the cargo hold.

1 is a cross-sectional view of the membrane-type liquefied gas carrier.
Figure 2 is a side view of the sloshing reducing means according to an embodiment of the present invention.
3 is a cross-sectional view taken along line III-III of FIG. 2;
4 is a longitudinal cross-sectional view of the upper fixing part indicated by A in FIG.
FIG. 5 is a longitudinal cross-sectional view of the lower support portion indicated by B in FIG. 2; FIG.
Figure 6 is a side view for explaining the operation of the sloshing reducing means according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view of the blade along the VIII-VIII straight line in FIG. 6; FIG.
8 is a side view showing a modification of the blade provided in the sloshing reducing means according to an embodiment of the present invention.
9 is a side view showing another modification of the blade provided in the sloshing reducing means according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

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

Figure 2 shows a sloshing reducing means according to an embodiment of the present invention, Figure 3 is a cross-sectional view along the line III-III of FIG. A sloshing reduction device according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3.

2 and 3, the sloshing reduction device 100 according to an embodiment of the present invention may include a support 110 and a surface flow reduction means 130. The surface flow reduction means 130 may include a hub 131 and a blade 133. In addition, the sloshing reduction device 100 according to an embodiment of the present invention may further include an upper stopper 111 and a lower stopper 112.

The strut 110 may be installed vertically in the cargo hold 20 of the membrane-type liquefied gas carrier (see 1 in FIG. 1) forming a barrier of liquefied gas with a metallic membrane.

Here, the vertical direction refers to the direction parallel to the direction in which gravity acts when the hull (see 10 in FIG. 2) maintains an equilibrium on the surface, and parallel means not a mathematical or geometric parallel, but mechanical machining error. It means the practical side-by-side considering the back.

Hub 131 may be installed on the support 110 to be slidably movable along the longitudinal direction of the support 110. In this case, the hub 131 may be rotatable about the support 110.

The hub 131 may be provided with a plurality of blades 133 radially. At this time, the number of blades 133 may be added or subtracted as needed, and the blades 133 may be installed at equal intervals as shown in FIG. 3, or may be installed without forming equal intervals.

The surface flow reduction means 130 including the hub 131 and the blade 133 has a specific gravity smaller than that of the liquefied gas, which will be described with reference to FIG. 6.

The upper stopper 111 and the lower stopper 112 may be installed on the support 110. The upper stopper 111 and the lower stopper 112 are coupled to the upper side and the lower side of the support 110, respectively, to limit the range in which the hub 131 can slide along the longitudinal direction of the support 110. That is, the hub 131 is slidably movable along the support 110 in the section between the upper stopper 111 and the lower stopper 112.

A portion denoted by A in FIG. 2 is an upper fixing portion at which the upper end of the support 110 is fixed, and a portion denoted by B is a lower support portion, which will be described with reference to FIGS. 4 and 5.

FIG. 4 is a longitudinal sectional view of the upper fixing part denoted by A in FIG. 2.

Referring to FIG. 4, a sleeve 120 and a first sealing plate 140 may be included in an upper fixing part of the sloshing reducing means (see 100 of FIG. 2) according to an exemplary embodiment of the present invention.

The upper fixing part of the sloshing reducing means 100 according to an embodiment of the present invention may fix the upper end of the support 110 to the hull (see 10 of FIG. 1) of the liquefied gas carrier ship (see 1 in FIG. 1). . That is, as shown, the upper end of the support 110 may be fixed to the outer hull 11 and the inner hull 12.

The sleeve 120 has a hollow cylinder shape, and may pass through the hull (see 10 of FIG. 1) and be coupled to the hull (see 10 of FIG. 1). That is, the sleeve 120 may be coupled in a shape that penetrates the inner hull 12 and the outer hull 11.

For reference, the hull (see 10 in FIG. 1) illustrates a case of a double hull structure having an outer hull 11 and an inner hull 12, and the outer hull 11 and the inner hull 12 are illustrated in FIG. Likewise, a plurality of reinforcing materials 13 may be installed to improve strength.

The sleeve 120 may be joined by welding to the hull (see 10 of FIG. 1). That is, the upper side of the sleeve 120 may be welded to the outer hull 11 to form a welded portion 121, and the lower side of the sleeve 120 may be welded to the inner hull 12 to form a welded portion 124. can do.

At this time, the welds 121 and 124 may be formed to prevent water or air from passing through the water or air to the heat insulation structure 22 to be described below, or to prevent the heat insulation effect of the heat insulation structure 22 from being lowered. have.

The upper end of the support 110 may be coupled to the hollow portion of the sleeve 120. The upper end of the support 110 and the sleeve 120 may be welded. That is, as shown, the upper end of the sleeve 120 is welded to the outer circumferential surface of the support 110 to form a welded part 122, and the lower end of the sleeve 120 is welded to the outer circumferential surface of the support 110 to be welded ( 123 may be formed.

Here, the welds 122 and 123 may also be formed to prevent water or air from passing through, like the welds 121 and 124 described above.

The membrane 21 may have a pleat 21a as shown. Since the membrane 21 is in direct contact with the cryogenic liquefied gas (not shown) stored in the cargo hold 20, shrinkage and expansion may occur due to a sudden temperature difference. Excessive stress may be applied to the membrane 21 when the membrane 21 contracts and expands, and thus the wrinkle 21a is formed to prevent the membrane 21 from being damaged by such expansion and contraction.

The thermal insulation structure 22 may include a secondary barrier (not shown) and a plurality of thermal insulation layers (not shown) disposed on both sides of the secondary barrier (not shown).

For reference, the secondary barrier (not shown) is to prevent liquefied gas from leaking out of the cargo hold (see 20 in FIG. 1) when the membrane 21, which is the primary barrier, is damaged. It may be made of a composite triplex (rigid triplex) and the like. The heat insulation layer (not shown) may be made of polyurethane or the like that can withstand cryogenic temperatures.

Such a heat insulating structure 22 is generally applied to the cargo hold (see 20 in FIG. 1) of the membrane-type liquefied gas carrier (see 1 in FIG. 1), and a detailed description thereof will be omitted.

The strut 110 may be installed to penetrate the membrane 21 and the insulating structure 22 as shown. The first sealing plate 140 is installed at a portion through which the membrane 21 is penetrated by the support 110, thereby preventing liquefied gas (not shown) from leaking into this portion.

That is, the first sealing plate 140 is disposed in the portion through which the membrane 21 penetrates by the support 110, and is coupled to the outer circumferential surface of the support 110 and the membrane 21, so that the support 110 and the membrane ( 21) Seal the gap.

In this case, the first sealing plate 140 may be welded to the outer circumferential surface of the support 110 and the membrane 21. In more detail, portions of the first sealing plate 140 and the outer circumferential surfaces of the support 110 that are in contact with each other may be welded to each other to form a weld 142, and the first sealing plate 140 and the membrane 21 may be The contacting portions may be welded to each other to form a weld 141.

Here, the welding parts 141 and 142 may be welded to seal the liquefied gas so that it does not flow out. In particular, since the weld 141 should not be cracked due to a sudden temperature difference, the first sealing plate 140 may be made of the same material as the membrane 21, and used to form the weld 141. Welding rods (not shown) may also be selected and used to be made of the same material as the membrane (21).

The strut 110 may also expand and contract due to a sudden temperature difference. If the volume change due to expansion and contraction is large, a crack may be generated in the weld 142. Accordingly, the support 110 may be made of a material having a low thermal expansion rate and sufficient rigidity even at low temperatures. Examples of the material include aluminum steel, stainless steel, and low temperature nickel steel.

When the liquefied gas is stored in the cargo hold (see 20 of FIG. 2), the support 110 may be in direct contact with the liquefied gas. Therefore, a hollow portion (not shown) may be formed in the support 110 to minimize the transfer of external heat to the liquefied gas through the upper end of the support 110 exposed to the outside of the outer hull 11. .

For reference, it is well known that the bending strength of the hollow shaft is superior to the solid shaft when the solid shaft and the hollow shaft are manufactured with the same length of material. That is, when the solid shaft and the hollow shaft have the same bending strength, the hollow shaft can be made of a smaller amount of material, so that the weight and the cross-sectional area of the hollow shaft are smaller than the solid shaft.

Therefore, when the hollow part (not shown) is formed in the support 110, since the cross-sectional area is reduced compared to the case where the hollow part is not formed, heat transfer through the support 110 can be reduced, and the weight of the support 110 is also reduced. It is possible. However, the upper and lower surfaces of the support 110 may be sealed to prevent the passage of the liquefied gas, and a lightweight insulating material may be inserted into the hollow portion (not shown) of the support 110.

As described above, the upper fixing portion of the sloshing reducing means 100 according to an embodiment of the present invention can firmly fix the upper end of the support 110 to the hull (see 10 in FIG. 1), the liquefied gas ( (Not shown) may be prevented from leaking out of the cargo hold (see 20 in FIG. 1).

On the other hand, the lower end of the support 110 may be supported to be movable relative to the hull (see 10 of FIG. 1). This is to be able to support the force applied to the support 110, while being able to respond to the change in length due to the temperature difference of the support 110, the reason is as follows.

First, when the support 110 expands and contracts due to a sudden temperature difference, the overall length and diameter of the support 110 may be changed. Therefore, assuming that the lower end of the support 110 is also firmly fixed to the hull (see 10 in FIG. 1) like the upper end, the support 110 or the hull (see 10 in FIG. 1) when the length of the support 110 is changed. ) May be deformed or damaged.

Therefore, the lower end of the support 110 should be able to respond to changes in the length and diameter of the support 110 by the temperature difference.

Next, when a sloshing phenomenon occurs in the liquefied gas stored in the cargo hold (see 20 of FIG. 2), a force in various directions may be applied to the surface flow reduction means 130. The upward and downward components of such a force may be hardly transmitted to the support 110 by the vertical movement of the surface flow reduction means 130, but the transverse components may be transmitted to the support 110 in most cases.

If it is assumed that the lower end of the support 110 is not fixed to the hull (see 10 in FIG. 1) in order to correspond to the change in length and diameter due to the temperature difference of the support 110, the transverse force of the force transmitted to the support 110 is assumed. The strut 110 can be bent or broken by the directional component and the resulting moment.

Thus, the lower end of the support 110 should be able to support the transverse component of the force transmitted to the support 110.

Therefore, the lower end of the support 110 may be supported to be movable relative to the hull (see 10 of FIG. 1), which will be described with reference to FIG.

FIG. 5 is a longitudinal cross-sectional view of the lower support portion indicated by B in FIG. 2.

Referring to FIG. 5, the lower support part of the sloshing reducing means (see 100 of FIG. 2) according to an embodiment of the present invention may include a housing 150, a second sealing plate 160, and a housing supporter 170. have.

The lower support portion of the sloshing reducing means 100 according to an embodiment of the present invention supports the lower end of the support 110 to the hull (see 10 of FIG. 1) of the liquefied gas carrier ship (see FIG. 1). can do.

The housing 150 is formed with an accommodating part 151, and the lower end of the support 110 may be inserted into the accommodating part 151. At this time, the receiving portion 151 may be formed to be spaced apart from the outer peripheral surface and the lower surface of the lower end 110. This is to prevent the influence from being transmitted to the housing 150 even if the length and diameter of the support 110 are changed by the temperature difference.

At this time, the lower end of the support 110 may be moved laterally by a distance C formed between the inner circumferential surface and the outer circumferential surface of the lower end of the support 110 by the force generated by the sloshing phenomenon as described above. That is, the lower end of the support 110 may be supported by the housing 150 such that the lower end of the support 110 may flow in the lateral direction by the gap C, but does not flow beyond that range. However, the size of the interval (C) may be set within the range that the support 110 does not deviate from the elastic limit.

Accordingly, the lower end of the support 110 may be supported to be movable relative to the housing 150.

The housing 150 is supported on the hull (see 10 of FIG. 1) by the housing supporter 170. The housing supporter 170 is coupled to the inner surface of the hull (see 10 in FIG. 1), that is, the inner surface of the inner hull 12, and is interposed between the hull (see 10 in FIG. 1) and the housing 150 to seal the housing 150. I support it. In this case, the housing supporter 170 may be welded to the inner hull 12 to form a weld 171.

The housing 150 may be installed in a shape penetrating the membrane 21 as shown. The second sealing plate 160 is installed at a portion through which the membrane 21 penetrates by the housing 150, thereby preventing liquefied gas (not shown) from leaking to the portion.

That is, the second sealing plate 160 is disposed at a portion through which the membrane 21 penetrates by the housing 150, and is coupled to the outer circumferential surface of the housing 150 and the membrane 21, so that the housing 150 and the membrane ( 21) Seal the gap.

In this case, the second sealing plate 160 may be welded to the outer circumferential surface of the housing 150 and the membrane 21. That is, portions of the second sealing plate 160 and the outer circumferential surfaces of the housing 150 that are in contact with each other may be welded to each other to form a weld 152, and portions of the second sealing plate 160 and the membrane 21 that are in contact with each other. The welding portion 161 may be welded to each other to form a weld 161.

Here, the welding parts 152 and 161 may be welded to seal the liquefied gas so that it does not leak. Since the weld 161 should not cause cracks or the like due to a sudden temperature difference, the second sealing plate 160 may be made of the same material as the membrane 21, and a welding rod used to form the weld 161 ( It may also be formed of the same material as the membrane 21.

The housing 150 may also expand and contract due to a sudden temperature difference. If the volume change due to expansion and contraction is large, cracks may occur in the weld 152. Accordingly, the housing 150 may be made of a material having a low thermal expansion and sufficient rigidity, but may be made of the same material as the pillar 110 described above.

As described above, the lower support portion of the sloshing reducing means 100 according to an embodiment of the present invention may support the support 110 in a flowable manner with respect to the hull (see 10 in FIG. 1), and the liquefied gas ( (Not shown) may be prevented from leaking out of the cargo hold (see 20 in FIG. 1).

Since the wrinkle part 21a is as above-mentioned, the overlapping description is abbreviate | omitted. In addition, since the reinforcing material 13 is also the same as that described with reference to FIG. 4, redundant description is omitted.

For reference, as an example, the installation process of the sloshing reducing means (see 100 of FIG. 2) according to an embodiment of the present invention. It demonstrates with reference to FIG. 4 and FIG.

The outer hull 11 and the inner hull 12 are formed with coupling holes (not shown) to which the sleeve 120 is to be welded. At this time, the coupling hole (not shown) may be formed in advance in the corresponding block (block) before the hull (see 10 of FIG. 1) is assembled, the position where the coupling hole (not shown) is to be formed hull (Fig. 1). Can be considered from the design stage).

After the hull (10 of FIG. 1) is assembled, the housing supporter 170 may be disposed and welded to the inner surface of the inner hull 12 to form a weld 171. The position at which the housing supporter 170 is to be coupled to the inner hull 12 may also be marked in advance from the design stage, such as marking. The housing 150 is disposed on the housing supporter 170 provided in the inner hull 12.

On the other hand, the strut 110 and the sleeve 120 may be pre-coupled separately from the assembly process of the hull (see 10 of FIG. 1). In this case, the support 110 and the sleeve 120 may be temporarily assembled, that is, the upper end of the support 110 may be inserted into the sleeve 120.

After the housing 150 is disposed, the support 110 having the sleeve 120 coupled to the coupling hole (not shown) may be inserted. At this time, the depth of the support 110 is inserted into the coupling hole (not shown) so that the distance (D) formed by the bottom surface of the support 110 and the bottom surface of the receiving portion 151 is within the allowable range determined at the design stage. Can be adjusted.

When the insertion of the support 110 is completed, the support 110, the sleeve 120, the outer hull 11, and the inner hull 12 may be welded to each other to form welds 121, 122, 123, and 124.

Thereafter, the heat insulation structure 22 may be installed in the inner hull 12. After the insulating structure 22 is installed, the first sealing plate 140 and the second sealing plate 160 may be disposed on the insulating structure 22. In addition, the first sealing plate 140 may be welded to the outer circumferential surface of the support 110 to form a welding part 142, and the second sealing plate 160 may be welded to the outer circumferential surface of the housing 150 to be welded ( 152 may be formed.

Next, the membrane 21 may be coupled onto the insulating structure 22. After the coupling of the membrane 21 and the heat insulating structure 22, the welding portion 141 may be formed by welding the first sealing plate 140 and the membrane 21 to each other, and the second sealing plate 160 and the membrane ( The welding part 161 may be formed by welding 21 to each other.

By the above process, the sloshing reducing means (see 100 of FIG. 2) according to the exemplary embodiment of the present invention may be installed in the hull (see 10 of FIG. 1). Here, the above-described installation process is an example, and may be changed as necessary.

Figure 6 is a side view for explaining the operation of the sloshing reducing means according to an embodiment of the present invention.

Referring to FIG. 6, the sloshing reduction device 100 according to an embodiment of the present invention reduces the sloshing phenomenon of the liquefied gas 50. That is, the surface flow reduction means 130 is located on the liquid level 51 of the liquefied gas 50 stored in the cargo hold 20, thereby suppressing the surface flow generated in the liquid level 51 of the liquefied gas 50. The occurrence of the sloshing phenomenon of 50 is reduced.

Since the surface flow reduction means 130 should be able to rise to the liquid surface 51 of the liquefied gas 50, the specific gravity of the surface flow reduction means 130 should be smaller than that of the liquefied gas 50. Therefore, the hub 131 and the blade 133 may be made of a material whose specific gravity is smaller than that of the liquefied gas 50, or may be manufactured with a structure in which the specific gravity may be smaller than the liquefied gas 50.

In particular, the blade 133 is applied with a force due to the surface flow of the liquefied gas 50, this force is transmitted to the hub 131 through the blade 133. Therefore, the hub 131 and the blade 133 may be made of a material having cold resistance and sufficient rigidity, and examples thereof include glass fiber, carbon fiber, aluminum steel, and the like.

For reference, examples of liquefied gas include liquefied natural gas (Liquefied Natural Gas, LNG) and liquefied petroleum gas (Liquefied Petroleum Gas, LPG). The proportion of liquefied natural gas to water is about 0.42 and that of liquefied petroleum gas to water is about 1.52. Therefore, if the surface flow reduction means 130 is manufactured so that the specific gravity with respect to water is less than 0.42, the surface flow reduction means 130 can rise to the surface of the liquefied natural gas and liquefied petroleum gas.

Therefore, the sloshing reducing means 100 according to an embodiment of the present invention is formed regardless of the amount of the liquefied gas 50 stored in the cargo hold 20, that is, the liquid surface 51 is formed in the cargo hold 20. It is possible to prevent the cargo hold from being damaged by suppressing the sloshing phenomenon regardless of the height.

At this time, the surface flow reduction means 130 should be able to move in the range of the height of the liquid surface 51 is formed according to the amount of the liquefied gas 50 which may damage the cargo hold 20 by the sloshing phenomenon, The upper stopper 111 and the lower stopper 112 may be installed at appropriate positions of the support 110 in consideration of this.

FIG. 7 is a cross-sectional view of the blade along the VIII-VIII straight line of FIG. 6.

Referring to FIG. 7, the cross section of the blade 133 of the sloshing reducing means (see 100 of FIG. 2) according to the exemplary embodiment may have an elliptical shape.

If the liquefied gas (see 50 in FIG. 6) slumps when the blade 133 is located at the liquid level (see 51 in FIG. 6) of the liquefied gas (see 50 in FIG. 6), the liquid level (see 51 in FIG. 6) becomes a blade. It can flow in up-down direction and vortex shape with respect to 133.

When the blade 133 has an elliptical cross section long in the vertical direction, the force applied to the blade 133 by the vertical flow of the liquefied gas (see 50 in FIG. 6) is reduced, and the liquefied gas (see 50 in FIG. 6). ) Horizontal flow can also be reduced.

In order to further improve this effect, the cross section of the blade 133 may be manufactured to have a streamlined shape or a semi-circle shape not shown.

In addition, as shown in the blade 133, a hollow portion 133a may be formed along its longitudinal direction. This is to reduce the specific gravity of the blade 133, so that the blade 133 can rise to the liquid level (see 51 of FIG. 6) of the liquefied gas (see 50 of FIG. 6) while having sufficient rigidity.

8 illustrates a modification of the blade provided in the sloshing reducing means according to an embodiment of the present invention.

Referring to FIG. 8, a protrusion 135 protruding downward may be formed in a lower portion of the blade 134 of the sloshing reducing means (see 100 of FIG. 2) according to an exemplary embodiment of the present invention.

The protrusion 135 has a liquid level (see 51 in FIG. 6) and a blade 134 of the liquefied gas (see 50 in FIG. 6) when a vertical flow of the liquefied gas (see 50 in FIG. 6) occurs as described above. It is for alleviating the impact force caused by the collision of the lower part.

When the blade 134 strongly collides with the liquid level (see 51 in FIG. 6) of the liquefied gas (see 50 in FIG. 6), the impact force is transmitted to the liquefied gas (see 50 in FIG. 6) to liquefied gas (50 in FIG. 6). As the temperature of the temperature increases, the amount of boil-off gas (BOG) may increase. Therefore, by forming the protrusion 135 in the lower portion of the blade 134 to reduce the impact force it is possible to reduce the generation of BOG.

The protrusion 135 may be formed in an intermediate region of the lower portion of the blade 134 as shown, or may be formed at any position between the lower portion of one end of the blade 134 and the lower portion of the other end, although not shown. Can be.

And, as shown in the blade 134 one protrusion 135 may be formed, one or more protrusions (not shown) may be further formed.

9 shows another modification of the blade provided in the sloshing reducing means according to an embodiment of the present invention.

Referring to FIG. 9, the blade 136 of the sloshing reducing means (see 100 of FIG. 2) according to an embodiment of the present invention may have a wider portion 137 having a wider upper and lower width in an intermediate region than both ends thereof. Can be. Here, since the protrusion 138 has the same configuration and effect as the protrusion (see 135 of FIG. 8) described with reference to FIG. 8, description thereof will be omitted.

The sloshing phenomenon has a significant effect not only on the vertical flow of the liquefied gas (see 50 in FIG. 6) but also on the horizontal flow, that is, the swirl flow. The wider portion 137 can apply a greater resistance to the horizontal flow of such liquefied gas (see 50 in FIG. 6), so that the sloshing reduction means (see 100 in FIG. 2) according to an embodiment of the present invention. The effect of reducing the phenomenon can be further improved.

Although the sloshing reducing means according to the embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention are within the scope of the same idea. Other embodiments may be easily proposed by adding, changing, deleting, or adding components, but this will also fall within the spirit of the present invention.

11: outer hull 12: inner hull
20: cargo hold 21: membrane
22: insulation structure 100: sloshing reduction device
110: prop 111: upper stopper
112: lower stopper 120: sleeve
130: surface flow reduction means 131: hub
133: blade 140: first sealing plate
150: housing 160: second sealing plate
170: housing supporter

Claims (11)

Struts installed vertically in the cargo hold of the membrane-type liquefied gas carrier ship to form a barrier of liquefied gas with a metal membrane; And
It is installed to be slidably movable along the longitudinal direction of the support, and includes a surface flow reduction means having a specific gravity smaller than the liquefied gas,
The surface flow reduction means,
A hub slidably installed on the support; And
A sloshing reducing means, characterized in that it comprises a plurality of blades radially installed in the hub.
The method of claim 1,
An upper fixing part for fixing an upper end of the support to the hull of the liquefied gas carrier; And
Sloshing reducing means further comprises a lower support for supporting the lower end of the support to the hull so as to flow.
The method of claim 2,
Upper fixing part,
A hollow cylinder sleeve which penetrates the hull and is coupled to the hull, and the hollow portion has an upper end of the support coupled thereto; And
And a first sealing plate disposed in a portion through which the membrane is penetrated by the support, and coupled to an outer circumferential surface of the support and the membrane to seal between the support and the membrane.
The method of claim 3,
The sleeve is welded to the hull,
An upper end of the post is welded to the sleeve,
And the first sealing plate is welded to the outer circumferential surface of the support and the membrane.
The method of claim 2,
The lower support portion,
A housing having a receiving part configured to receive a lower end of the support in one side;
A housing supporter coupled to the inner surface of the hull and interposed between the hull and the housing to support the housing; And
And a second sealing plate disposed in a portion through which the membrane is penetrated by the housing, and coupled to an outer circumferential surface of the housing and the membrane to seal the gap between the housing and the membrane. .
The method of claim 5,
The housing supporter is welded to the inner surface of the hull,
And the second sealing plate is welded to the outer circumferential surface of the housing and the membrane.
The method of claim 1,
Sloshing reduction means further comprises an upper stopper and a lower stopper coupled to the upper and lower sides of the support, respectively, to limit the slideable range of the hub.
The method of claim 1,
Sloping reduction means characterized in that the cross section of the blade has any one of the shape of elliptical, streamlined or semi-circular.
The method of claim 8,
Sloshing reducing means characterized in that the lower portion of the blade is formed with at least one protrusion protruding downward.
The method of claim 8,
The blade has a sloshing reduction means, characterized in that the upper and lower width of the intermediate region is wider than both ends.
The method of claim 8,
The blade is sloshing reducing means, characterized in that the hollow portion is formed along the longitudinal direction.

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