KR20130004596A - Liquefied gas carrying ship - Google Patents

Abstract

By reducing the hydraulic pressure area of the whole hull, the wind pressure resistance can be reduced, thereby lowering the center position of the ship, thereby improving the stability of the hull. A plurality of flat spherical tanks 2 arranged along the bow and tail direction and fixed to the hull 5 via a skirt 3 while storing gas liquefied therein, and these flat spherical tanks 2 With one continuous tank cover 7 extending along the fore and aft direction, with the tank cover 7 being firmly coupled to the hull 5, covering the upper half of the It was set as the liquefied gas carrier ship 1 integrated with the ship body 5 and having the structure which ensures a longitudinal strength.

Description

Liquefied Gas Carrier {LIQUEFIED GAS CARRYING SHIP}

The present invention relates to a liquefied gas carrier, and more particularly, to an LNG carrier for storing and transporting liquefied natural gas (LNG) in a tank.

As a liquefied gas carrier that stores and transports liquefied natural gas (LNG) in a tank at low temperature, the upper half of a plurality of spherical tanks arranged along the bow direction is covered with one continuous tank cover. One liquefied gas carrier is known (see Patent Document 1).

Japanese Patent Publication No. 2005-521589

However, in the (true) spherical tank, since the hull cross section of an LNG carrier is substantially square, the ratio of the volume in tank to the volume of the inboard compartment which mounts while supporting a spherical tank with a skirt is small, and volumetric efficiency is bad. For this reason, the tank cannot be completely stored in the hull, resulting in an enlargement of the hull. In addition, since the tank and the tank cover protrude high on the deck, the view from the bridge is bad, and with this, an upper structure having a high height is required. Accordingly, there has been a problem that the hydraulic pressure area of the entire hull is increased, the wind pressure resistance is increased, the center position of the ship is increased, and the stability is deteriorated.

The present invention has been made in view of the above circumstances, and provides a liquefied gas carrier that can reduce the hydraulic pressure area of the entire hull, reduce wind pressure resistance, lower the center position of the ship, and improve the stability of the hull. It aims to do it.

MEANS TO SOLVE THE PROBLEM This invention employ | adopted the following means in order to solve the said subject.

The liquefied gas carrier ship which concerns on this invention is equipped with several flat spherical tanks arrange | positioned along fore and aft direction and fixed to a ship body through a skirt while storing the liquefied gas inside, and the upper half part of these flat spherical tanks. And a continuous tank cover extending along the fore and aft direction, wherein the tank cover is firmly coupled to the hull to be integral with the hull to secure longitudinal strength. A liquefied gas carrier having a structure to be described above, wherein the flat spherical tank has a cylindrical portion and a top portion of the cylindrical plate structure convex upwardly arranged above the cylindrical portion, above the equatorial portion. And a bottom portion of the hard plate structure which is connected to the lower portion of the cylindrical portion below the equator and is convex downward, and has a diameter in the vertical direction of the equator. There is a shorter flat initiatives.

According to the liquefied gas carrier ship according to the present invention, when compared with a (true) spherical tank having a radius equal to the radius of the horizontal cross section of the equator, a larger volume is ensured than the spherical tank at the same height. The height is reduced compared to the bulb tank.

This reduces the height from the bottom to the top surface of the tank cover (2% to 25%), reduces the hydraulic pressure area of the entire hull, and reduces the wind pressure resistance, as compared with the case of employing a spherical tank in the same volume. By lowering the center position of the ship, the stability of the hull can be improved.

In the liquefied gas carrier, the height from the bottom of the liquefied gas carrier to the top surface of the tank cover is 2% to 25 higher than the height from the bottom of the liquefied gas carrier to the top surface of the tank cover when a spherical tank is employed at the same volume. It is more preferable if it is reduced in%.

According to such a liquefied gas carrier ship, when compared with a (true) spherical tank having a radius equal to the radius of the horizontal cross section of the equator, a large volume of the liquefied gas carrier ship is ensured at the same height. The height from the bottom to the top of the tank cover is reduced compared to the bulbous tank in the same volume.

This reduces the height from the bottom to the top surface of the tank cover (2% to 25%), reduces the hydraulic pressure area of the entire hull, and reduces the wind pressure resistance, as compared with the case of employing a spherical tank in the same volume. By lowering the center position of the ship, the stability of the hull can be improved.

In the liquefied gas carrier, the total volume of the flat spherical tank in the tank is more preferably 150,000 m 3 or more.

According to such a liquefied gas carrier ship, when compared with a (true) spherical tank having a radius equal to the radius of the horizontal cross section of the equator, a large volume of the spherical tank is secured at the same height, so that the spherical tank has the same volume. The height is further reduced.

This reduces the height from the bottom to the top surface of the tank cover (2% to 25%), reduces the hydraulic pressure area of the entire hull, and reduces the wind pressure resistance, as compared with the case of employing a spherical tank in the same volume. By lowering the center position of the ship, the stability of the hull can be improved.

In the liquefied gas carrier, a walkway is provided on which a gangway ladder is placed, which is provided at a terminal designed for carrying out a loading operation, above the upper deck positioned between the side face of the tank cover and the side shell plate. It is more preferable if there is.

According to such a liquefied gas carrier, the gangway ladder installed in the terminal is placed on the upper surface of the workway, so that even when the upper deck is placed in a low position, the gangway ladder installed in the terminal can be laid over the terminal. The suitability for gangway ladders can be made good.

In the liquefied gas carrier ship in which the walkway is formed, the height H (m) from the bottom to the upper surface of the workway is greater than the height D (m) + 2 (m) from the bottom to the upper surface of the upper deck, 40 ( m) It is more preferable that it is set to the height which can fall across the gangway ladder provided in the terminal which is smaller than a smaller range, and is intended.

In addition, the "terminal for which the ship is scheduled" means a terminal for which the main ship is scheduled to arrive after the service and / or a new terminal for which the ship which is already in service has come to attention due to a change of route or the like.

According to such a liquefied gas carrier, the height from the bottom to the upper surface of the walkway (that is, the height from the upper surface of the upper deck to the upper surface of the walkway) is arranged in accordance with the movable range of the gangway ladder installed in the terminal where the target is intended. Since the gangway ladder is placed on the upper surface of the walkway, even if the upper deck is placed in a low position, all the gangway ladders installed in the terminal where the user is scheduled to be laid can be laid, and the gangway ladder installed in the terminal The suitability for can be made good.

According to the liquefied gas carrier ship according to the present invention, the hydraulic pressure area of the whole hull can be reduced, the wind pressure resistance can be reduced, the center position of the ship can be lowered, and the stability of the hull can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure of the liquefied gas carrier ship which concerns on one Embodiment of this invention, FIG. 1 (a) is a right side view, and FIG. 1 (b) is a top view.
FIG. 2 is a sectional view seen from the direction of the II-II arrow in FIG.
3 is a view of a liquefied gas carrier ship according to one embodiment of the present invention, FIG. It is sectional drawing seen from the direction of BB arrow.
4 is a cross-sectional view taken from the direction of arrow IV-IV of FIG. 1 (a).
Fig. 5 is a side view of the flat spherical tank shown in Figs. 1 to 3 (a).

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of the liquefied gas carrier ship which concerns on this invention is described, referring FIGS.

1 (a) is a right side view, Fig. 1 (b) is a plan view, Fig. 2 is a sectional view taken along a line II-II in Fig. 1 Fig. 3 is a view of the liquefied gas carrier according to the present embodiment. Fig. 3 (a) is a sectional view taken along the line A-A in Fig. 1 Fig. 4 is a sectional view taken along the line IV-IV in Fig. 1 (a), and Fig. 5 is a side view of the flat ball tank shown in Figs. 1 to 3 (a).

As shown to FIG. 1 (a), FIG. 1 (b), and FIG. 3 (a), the liquefied gas carrier ship which concerns on this embodiment ("LNG ship" in this embodiment) 1 is, for example, It is a ship provided with four aluminum flat spherical tanks (also called "non-jinbulb spherical tanks") (2), and these aluminum flat spherical tanks (2) each have a liquefied gas therein (at low temperatures in this embodiment). Liquefied natural gas).

As shown in FIG. 5, the flat spherical tank 2 has a flat spherical shape having a diameter in the vertical direction slightly shorter than that of the equator, that is, a slightly flat and slightly rectangular shape, in other words, inside the hull 5. It is a tank formed so that the generation of unnecessary space is small and the amount of protrusion of the hull 5 upward is small. Above the equatorial portion (northern hemisphere) of the flat spherical tank 2, a cylindrical portion 31 having a radius R and a height H2 and a top portion which is provided in succession above the cylindrical portion 31 and has a hard plate structure convex upward of the height H1 ( 32) is formed, and below the equator portion (the southern hemisphere) of the flat spherical tank 2, a bottom portion 33 having a light plate structure which is provided in succession below the cylindrical portion 31 and is convex below the height H3 is formed. .

The top part 32 is equipped with the torus part 34 and the square part 35. As shown in FIG.

The torus part 34 is provided continuously in the upper part of the cylindrical part 31, for example, is formed by a part of the sphere of radius R2 in the range to (theta) 1 = 60 degrees.

The corner part 35 is provided in succession above the torus part 34, and is formed by a part of sphere of radius R1.

Further, R2 is α × R (radius of the horizontal cross section of the equator (hereinafter referred to as “radius of the equator”)). For example, when α is 0.5, R2 is 0.5 times of R (radius of the equator). do.

R1 is β × R, β is (1-α + α × COSθ1) / COSθ1. For example, when θ1 is 60 ° and α is 0.5, β is 1.5 and R1 is R. Is 1.5 times.

On the other hand, the bottom part 33 is equipped with the 1st corner part 36, the torus part 37, and the 2nd corner part 38. As shown in FIG.

The 1st corner part 36 is provided in the row below the cylindrical part 31, for example, is formed by a part of the sphere of radius R4 (= R) in the range to (theta) 4 = 25 degrees.

The torus part 37 is provided continuously in the lower part of the 1st corner part 36, for example, is formed by a part of the sphere of radius R5 in the range up to (theta) 5 = 38 degrees.

The 2nd corner part 38 is provided in succession below the torus part 37, and is formed by a part of sphere of radius R6.

In addition, R5 is (gamma) * R, for example, when (gamma) is 0.7, R5 becomes 0.7 times R.

R6 is δ × R, and δ is (1-γ) × COSθ4 / COS (θ4 + θ5) + γ, for example, when θ4 is 25 °, θ5 is 38 °, and γ is 0.7. δ becomes 1.299, and R6 becomes 1.299 times R.

In addition, in this embodiment, the ratio (a / b) of the maximum transverse dimension a of the torus portion 37 and the total longitudinal dimension b of the torus portion 37 and the second corner portion 38 is approximately 1.5 ( a / b ≒ 1.5), and the heights H1, H2, and H3 are set to satisfy the following formulas (1) to (3).

R / H1 = 1.5 (Equation 1)

2.5≤R / H2≤3.3 (Equation 2)

1.1≤R / H3≤1.2 (Equation 3)

In this case, when a / b ≒ 1.5 is set, the compression capacity generated in the portion of the bending ratio due to the internal pressure of the flat spherical tank 2 is kept sufficiently small, so that the internal buckling design is not necessary. Can be.

Moreover, when height H1, H2, and H3 were set so that said Formula (1)-Formula (3) might be satisfied, the preferable result on the stability as an LNG tank was obtained.

As shown in FIG. 2, these flat spherical tanks 2 each have a cylindrical skirt whose upper end is fixed to the equator of the flat spherical tank 2 and whose lower end is fixed on the foundation deck 4. It is supported by the hull 5 via 3). That is, the weight of these flat spherical tanks 2 is received by the hull 5 via the skirt 3.

1 (a), 1 (b), and 2, the upper half of these flat spherical tanks 2 is fixed at the upper deck 6 while the lower end thereof is fixed on the upper deck 6; It is covered by one continuous tank cover 7 extending along the line width direction. Moreover, no expansion joint is formed between the tank cover 7 and the upper deck 6 at all, and the tank cover 7 has a rigid structure. That is, the tank cover 7, together with the hull 5, has the weight, the load to be loaded, and the force of the wave against the longitudinal strength of the ship required in the rules of the Society of Classification and Societies. Strength against bending force and shear force generated by

In addition, the code | symbol 8, 9 in FIG. 2 has shown the longitudinal bulkhead and the ship side shell plate, respectively.

As shown in FIGS. 1A to 4, a plurality of ballast tanks 10 (17 in the present embodiment) are formed at the bottom of the hull 5 along a bow and tail direction and a line width direction. have.

Among these ballast tanks 10, the ballast tanks 10 other than the ballast tanks 10 arranged at the position closest to the bow are respectively along the circumferential direction of the flat spherical tank 2, and the flat spherical tank 2 The upper part arrange | positioned so that the lower part upper part of the ship top may be arranged, and the lower part arrange | positioned along the ship side direction along the ship side shell plate 9 and the bottom (bottom shell plate) 11 of the ship body 5 are provided.

Moreover, as shown to FIG. 1 (a), FIG. 1 (b), FIG. 2, and FIG. 4, along the ship side shell plate 9 to the port side and starboard side of the liquefied gas carrier ship 1 which concerns on this embodiment. One walkway (passage) 20 is formed.

The walkway 20 is laid with a gangway ladder (side ladder) provided at a terminal (not shown) designed to carry out a loading and unloading operation, and serves as a passage for crew members, workers, and the like. It is.

As shown in FIG. 2 and FIG. 4, the walkway 20 vertically upwards from the work deck 21 extending outward from the side surface 7a of the tank cover 7 and the upper deck 6 (or the tank cover). It extends toward the inclination upward from side surface 7a of (7), and is provided with the some support member 22 which supports the lower surface of the work deck 21. As shown in FIG.

As shown in FIG. 1 (a) and FIG. 1 (b), the walkway 20 is a tank cover 7 from the front surface of the house (residential port) 23 along the corresponding ship side shell plate 9. It extends to the front end of side 7a. In addition, on both ends of the work deck 21 (left end and right end in FIGS. 1A and 1B), the upper deck 6 is mounted on the upper deck 6 from the work deck 21. ) Are provided with stairs (not shown) for climbing on the work deck 21 from each other.

And the height (vertical distance) H (m) from the bottom 11 to the upper surface of the work deck 21 is the height D (m) + 2 (m) from the bottom 11 to the upper surface of the upper deck 6. It is set to a height which is larger, within a range of less than 40 (m), and which can span all of the gangway ladders installed in the terminal where the user is expected to take (after service).

According to the liquefied gas carrier ship 1 which concerns on this embodiment, when compared with the true spherical tank which has the radius R equal to the radius R of the horizontal cross section of an equator, since a large volume is ensured compared with a spherical tank at the same height, In the same volume, the height will be reduced than the bulb tank.

This reduces the height from the bottom 11 to the top surface 7b of the tank cover 7 (2% to 25%) as compared with the case of employing a spherical tank in the same volume, and reduces the hydraulic pressure area of the whole hull. In addition, the wind pressure resistance can be reduced, and the center position of the ship can be lowered, thereby improving the stability of the hull.

In addition, since the gangway ladder is placed on the upper surface of the workway 20 arranged in accordance with the movable range of the gangway ladder installed in the terminal where the target is scheduled, the upper deck 6 is disposed at a low position. In addition, all the gangway ladders installed in the terminal on which the concept is intended can be laid, so that the suitability for the gangway ladders installed in the terminal can be made good.

In addition, the mooring brackets are arranged on the upper deck 6 positioned below the work deck 21 in the same manner as in the prior art, so that the mooring brackets protrude upward from the upper surface of the work deck 21. Can be avoided, and the trafficability on the work deck 21 can be improved.

In addition, one continuous tank cover 7 covering the upper half of the entire flat spherical tank 2 is strongly coupled to the hull 5, and together with the hull 5, Since the longitudinal strength is ensured, the width of the hull 5 can be reduced by about 2% to 4%, the hull resistance and the hull weight can be reduced, and the navigation performance can be improved. The total amount of the material (for example, steel) which comprises (5) can be reduced, and reduction of drying cost can be aimed at.

And as shown in FIG. 2, since the upper part of the ballast tank 10 is arrange | positioned along the circumferential direction of the flat spherical tank 2, and surrounds the bottom upper part of the flat spherical tank 2, these ballasts are provided. The upper part of the tank 10 can be used as a part of the skirt 3 which supports the flat spherical tank 2, and the total amount of the material which comprises the skirt 3 can be reduced, and the drying cost of the Reduction can be aimed at.

Moreover, according to the liquefied gas carrier ship 1 which concerns on this embodiment, the following effects or advantages can also be acquired.

(1) The shape of the southern hemisphere of the flat spherical tank (2) is different from the conventional hard plate structure, and the radius of the vicinity of the liquid surface at the time of half-loading of the liquid liquid, that is, about 30 degrees south of the equator, is the radius. By being formed in a spherical shape substantially the same as the radius of the horizontal cross section of the equator, the buckling problem due to the shaking of the liquid at the time of complicated return can be designed with the same reliability as the conventional (true) spherical tank.

(2) The portion of the southern hemisphere of the flat spherical tank 2 below the above-described concrete portion, that is, below the southern portion of 30 degrees is formed in the torus portion 37 and the second spherical portion 38 at an aspect ratio (a / b) Is approximately 1.5, the compressive stress generated in the small curvature portion by the internal pressure is kept sufficiently small, and the buckling design is not required.

(3) The torus portion 37 which is provided in the southern hemisphere by a part of a sphere having a radius R4 equal to the radius R of the equator, and successively provided below the first corner portion 36; Since it is formed by two parts of the pseudo-ellipse part which consists of the 2nd corner part 38, manufacture of a southern hemisphere can be performed by joining both members, after manufacturing the 1st corner part 36 and the pseudo-ellipse part separately. . Therefore, what is necessary is just to design about each of the 1st corner part 36 and the similar ellipse part about intensity | strength, heat deformation, thickness, etc. As a result, design and manufacture of a southern hemisphere become easy.

(4) Since the torus portion 37 and the second corner portion 38 constituting the pseudo-elliptic portion are both formed as part of a sphere, the design and manufacture are easy.

(5) Since the torus portion 37 and the first corner portion 36 have the same tangent line, the torus portion 37 and the first corner portion 36 can be smoothly joined to each other, and as a result, at the junction of the torus portion 37 and the first corner portion 36, respectively. The occurrence of local bending stress can be suppressed and the appearance can also maintain smooth continuity.

(6) Said (2)-(5) enables simple design and manufacture of the southern hemisphere of the flat spherical tank 2.

Further, the present invention is more preferably applied to liquefied gas carriers having a total volume of 150,000 m 3 or more in the tank.

In a liquefied gas carrier having a total volume of 150,000 m 3 or more in the tank, since the tank and the tank cover are projected high on the deck conventionally, the view from the bridge is bad, and accordingly, a high height structure is required, and the whole hull The hydraulic pressure area increased, the wind pressure resistance increased, and the center position of the vessel became high, resulting in a problem of deterioration in stability.

However, by applying the present invention to a liquefied gas carrier having a total volume of 150,000 m 3 or more in the tank, the height from the bottom to the top of the tank (the north pole) and the top of the tank cover is increased compared with the case of employing a spherical tank at the same volume. (2% to 25%) can be reduced, the hydraulic pressure area of the whole hull can be reduced, the wind pressure resistance can be reduced, the center position of the ship can be lowered, the stability of the hull can be improved, and the conventional problems can be solved. It became.

In addition, although the above-mentioned embodiment demonstrated that the rear end of the walkway 20 extended to the front surface of the house 23, this invention is not limited to such a thing, but the rear end of the walkway 20 is described. For example, the walkway 20 extended to the side surface of the house 23 may be employed.

Then, the rear end of the walkway 20 and a certain layer (for example, 2nd Deck) in the house 23 are connected to each other via a watertight door (not shown) so that the house can be accessed. Convenience from the inside of the 23 to the walkway 20 or from the walkway 20 into the house 23 can be improved.

In addition, an electric wire, an oil pipe, which is conventionally arranged in a space formed below the upper deck 6 (a space surrounded by the foundation deck 4, the upper deck 6, the longitudinal bulkhead 8, and the side shell plate 9), It is more preferable if water piping, fire-extinguishing piping, compressed air piping, etc. are arrange | positioned in the open space (space formed between the work deck 21 and the upper deck 6) formed under the work deck 21.

As a result, maintenance and inspection work such as electric wires, oil pipes, water pipes, fire-extinguishing pipes, and compressed air pipes can be easily performed, and maintenance performance can be improved.

In addition, this invention is not limited to embodiment mentioned above, For example, in embodiment mentioned above, the inner peripheral surface of the skirt 3 and the upper part of the ballast tank 10 are comprised (formed). The inner circumferential surface of the wall portion (the wall portion existing along the circumferential direction of the flat spherical tank 2) 12 (see FIG. 2) is placed on the same plane, and the skirt 3 and the wall portion 12 are placed on the same member. Modifications and modifications can be made as necessary as appropriate within the scope of not departing from the technical idea of the present invention, such as a configuration.

In addition, in the above-described embodiment, the upper half of the four flat spherical tanks 2 has been described with one continuous tank cover 7 extending along the bow and down direction and the line width direction. It is not limited to such a thing, but it is applicable also to what provided with four tank covers corresponding to each flat spherical tank 2. As shown in FIG.

1: liquefied gas carrier
2: flat spherical tank
3: Skirt
5: hull
6: upper deck
7: tank cover
7a: side
7b: normal plane
9: side shell plate
11: bottom
20: Walkway
31: cylindrical part
32: top part
33: bottom

Claims (5)

A plurality of flat spherical tanks disposed along the bow and tail direction and fixed to the hull via a skirt while storing the gas liquefied therein;
While covering the upper half of these flat spherical tanks, it is provided with one continuous tank cover extending along the fore and aft direction,
A liquefied gas carrier ship having a structure in which the tank cover is strongly coupled to the hull and is integral with the hull to secure longitudinal strength,
The flat spherical tank is provided above the equatorial section with a cylindrical section, and is provided in succession above the cylindrical section, and has a top of a convex hard plate structure, and is located below the equatorial section. The liquefied gas carrier ship which is connected to the lower part and is provided with the bottom part of the hard-plate structure convex downward, and has a flat sphere shape whose diameter of a perpendicular direction is shorter than the diameter of an equator. The method of claim 1,
A liquefied gas carrier ship in which the height from the bottom to the top of the tank cover is reduced from 2% to 25% from the height from the bottom of the liquefied gas carrier to the top of the tank cover when a spherical tank is employed at the same volume. 3. The method according to claim 1 or 2,
The total volume in the tank of the said flat spherical tank is 150,000m <3> or more. The method according to any one of claims 1 to 3,
A liquefied gas carrier ship formed with a walkway over which a gangway ladder provided at a terminal conceived for carrying out an unloading operation is placed above an upper deck positioned between a side surface of the tank cover and a side outer plate. The method of claim 4, wherein
The height H (m) from the bottom to the upper surface of the workway is greater than the height D (m) + 2 (m) from the bottom to the upper surface of the upper deck and is within the range of less than 40 (m), A liquefied gas carrier that is set high enough to span all of the gangway ladders installed at this scheduled terminal.

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