JP3592683B2 - Piping device in tank where sloshing occurs - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piping device in which a plurality of pipes are provided vertically in a tank in which sloshing occurs.
[0002]
[Prior art]
As a conventional liquefied gas tank piping device which is an example of a tank in which sloshing occurs, a large-sized LNG ship is usually provided with a cylindrical pipe tower from the bottom to the top of the LNG tank, and various pipes and the like are provided therein. Outfittings were installed to allow people to pass through them. According to such a piping device, it is possible to safely and reliably protect the pipe and the like from the fluid force generated by sloshing of the LNG mounted on the LNG tank. However, the internal structure of the tank such as a pipe tower is a large-scale facility and has a high manufacturing cost.
[0003]
As shown in FIG. 5, in a so-called cylinder tank mounted on both ends of a hemispherical cylinder of a coastal LPG ship or the like, as shown in FIG. provided wash bulkhead 200 at a position closer to the tank center O of the front side of the group 100, a large sloshing pressures direction of arrow X _2, resulting from the long front side of the distance had to be relaxed. However, such a water control partition has a problem in that even if a large number of openings 201 are opened, there is a large number of accidents in which a large pressure is applied to itself and the mounting portion 202 is damaged.
[0004]
In addition, as a pipe tower for a large spherical LNG tank, only the float guide pipe is put in the pipe tower, and the other space in the tower is used as a space for loading / unloading the fuel oil pump, and other pipes and gratings are used. It has been proposed that the pipe tower be mounted outside the tower to reduce the diameter of the pipe tower from 4.3 m to 1.6 m to shorten the processing time and reduce the material cost (Japanese Patent Laid-Open No. 7-228289). reference). However, even with this structure, since the pipe tower is still provided, there is a problem that construction costs and material costs are high and manufacturing costs are high.
[0005]
On the other hand, as an LNG spherical tank that abolished the pipe tower, four rising pipes consisting of a loading pipe, two unloading pipes, and a float pipe for a liquid level gauge were arranged at intervals in a square cross section, These have a pipe tower structure in which the pipes are joined by passing the four pipes through the four corners of the intermediate support consisting of a total of seven plate-shaped reinforcing supports and lattices and plates, and the cargo handling pipes themselves are supported. Proposed. (See Japanese Utility Model Application Laid-Open No. 59-66097).
[0006]
However, in such a structure, the material for the pipe tower itself is not necessary, but the work of passing the four pipes through the support material and attaching it to the support material is a time-consuming and difficult work, so that the manufacturing cost is high. In addition, since the structure is such that four pipes are simply bundled with an interval therebetween, the structure is not sufficient to receive a sloshing force applied to the pipes from the lateral direction. In addition, since four pipes are required, this method cannot be applied to a tank that does not have four such pipes in the outfitting pipe, and the location of the four pipes is limited. There is a problem that the degree of freedom is limited.
[0007]
[Problems to be solved by the invention]
It is an object of the present invention to solve the above-mentioned problems in the prior art, and to provide a piping device capable of efficiently withstanding sloshing force, having a greatly simplified structure, low manufacturing cost, and efficient.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is directed to a liquefied gas tank of a liquefied gas carrier in which sloshing occurs, wherein two pipes having a large diameter in the vertical direction and two or more pipes having a small diameter are provided. In a piping device provided with a plurality of pipes including :
The plurality of pipes are provided so as to pass through the tank top from below the tank, and the two pipes are provided in parallel with each other in the vertical direction at an interval in the direction of the sloshing force. It is supported so as to receive a horizontal force at a position near the lower part and a position above a position near the tank top, and the two pipes are capable of resisting the force of the sloshing. A reinforcing plate for reinforcing the two tubes is combined, and the reinforcing plate is attached to the two tubes between at least a majority of upper and lower portions from the lower vicinity position to the upper position. From the joined position, the joining plate continuously joined to at least one of both surfaces of the joining plate at the middle position of the interval up to the same position as the joining plate in the vertical direction. Almost perpendicular to the direction of force Of a structure having a least one provided projecting on the side projecting plate, the other tubes except the two pipes of the plurality of tubes attached to said reinforcing plate, characterized in that.
[0010]
In the invention of claim 2 , in addition to the above, the tank is a horizontal cylindrical liquefied gas tank, and the plurality of pipes are provided at positions closer to one side from a center of the liquefied gas tank in the direction of the force. The majority of the small-diameter tubes of the plurality of tubes are attached to the side of the overhanging plate opposite to the center side.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an example of the entire configuration of a piping device to which the present invention is applied.
The piping device of this example is a device in which a plurality of pipes 3 are provided in the vertical direction Z in an LNG tank 2 as a tank in which sloshing occurs. And a plate 6. The LNG tank 2 is a liquefied gas carrier, and only a part of the LNG tank 2 is shown by a two-dot chain line. In this example, as three or more pipes provided so as to pass through the tank top portion 22 from a nearby position, in this example, two guide pipes 31, 32 for a float type liquid level meter, and a liquid supply pipe for loading LNG 33, discharge pipes 34, 35 of the oil pumps 34a, 35a, a spray liquid discharge pipe 36 for initial cooling down of the LNG tank, a stirring pipe 37, a spray pipe 38, two gas sampling pipes 39, And so on. Also, three pump driving electric wires 40 including a spray pump (not shown) are guided from below to above.
[0012]
These guide tubes 31 and 32 are two tubes provided in parallel with each other in the vertical direction Z at an interval d in the front-rear direction X which is the direction of the drag F due to the sloshing shown in FIG. The lower support member 7a provided at the position of the tank bottom 21 as a position near the bottom and the upper support member 7b provided at the tank top 22 in the present example as a position above the position near the tank top 22 are further usually provided. And the upper end support portion 7c provided on the upper portion of the tank dome 8 to be supported so as to be able to receive the force in the XY plane direction, which is the horizontal force.
[0013]
Such pipes 31, 32, etc. are arranged above the tank dome 8 in a similar manner to a normal structure, although not particularly shown, so that thermal deformation due to a large temperature difference between when the LNG is mounted and when the LNG is empty is free. It is suspended from above. Although not shown, the guide tubes 31 and 32 contain a float of a float type liquid level meter for displaying an LNG liquid level, an alarm, and the like in the same manner as an ordinary one.
[0014]
The coupling plate 5 reinforces two of the plurality of tubes 3 as described above so as to be able to oppose the drag F. In the present embodiment, the coupling plate 5 is a tube having a large diameter among the tubes 3. The two guide tubes 31 and 32 are connected to each other. The coupling range is between at least most of the upper and lower portions of the guide tubes 31 and 32 from a position near the tank bottom 21 to a position above a position near the tank top 22. the example is between the position P ₁ apart slightly above the tank bottom 21 to the position P ₂ below the upper support member 7c.
[0015]
In this example, the upper supporting members are both 7b and 7c, but may be only one of 7b and 7c. At that time, the coupling plate 5 is provided to a position slightly below 7b or 7c.
[0016]
Auxiliary plate 6 is joined from P ₁ position to the P ₂ position as the position of the same level as coupling plate 5 in the vertical Z-direction to an intermediate position Q of the both sides of the interval d in this example as at least one surface of both surfaces of the coupling plate 5 In the present example, at least one side in a direction substantially perpendicular to the X direction from the position Q is provided on both sides in the Y direction perpendicular to the position. The guide tubes 31, 32, the connecting plate 5, the auxiliary plate 6, etc. are usually made of aluminum material, and these are connected by welding.
[0017]
The LNG ship 1 has only a part thereof, but is provided with arc-shaped support tables 1c at two positions away from the center O in the X direction from the double bottom 1b formed on the ship bottom 1a. Supports the weight of the LNG tank 2. Reference numeral 1d is a cover. Although not shown, the outer periphery of the LNG tank 2 and the pipes that become cold on the outside of the tank are covered with a heat insulating material.
[0018]
The LNG tank 2 of this example is a horizontal cylindrical cylinder tank composed of a central cylindrical portion and hemispherical portions on both sides, and two pipes 31 and 32 are located at the center of the tank in the front-rear X direction. It is provided on the left side in the figure as one side from the line O. The other pipes except the guide pipes 31 and 32 which are at least one of the plurality of pipes 3 are attached to the reinforcing plate. In this example, the reinforcing plate is constituted by the coupling plate 5 and the auxiliary plate 6. have been tube 33,36～38 is attached to the face 6F ₁ after the opposite side of the center line O of the both sides of the auxiliary plate 6 as most of the small tube diameter of the plurality of tubes 3.
[0019]
Is small tube dimensions attached to the back surface 6F ₁ to as the principle, the force by sloshing according to tube support structure A broad this surface is increased, and the discharge pipe 34 and 35 shown in FIG. 3 In order to suspend and support the oil pumps 34a, 35a as described above, the oil pumps 34a, 35a are linearly coupled to the pumps from above. At the free end side, a flange 61 is attached, discharge pipes 34 and 35 are attached to these, a gas sample pipe 39 and a part of the electric wire 40 are attached to the rear of the guide pipe 31, and a part of the electric wire 40 is attached to the connecting plate. It is attached to the rear face 6F _1-side portion of the house.
[0020]
Each tube 3 is attached to the connecting plate 5, the auxiliary plate 6, and the flange 61 by an appropriate number of bands 9 provided in the vertical direction. Reference numeral 10 denotes a standing ladder attached to the guide tube 31. The liquid supply pipe 33 and the like are bent laterally above the oil filling pump 34a.
[0021]
FIG. 3 shows an example of an arrangement state of the oil pump in the LNG tank 2.
The oil pumps 34a, 35a are suspended and supported by the discharge pipes 34, 35 from above as described above, and a lower end portion having a suction port is formed below a part of the tank bottom 21 so that LNG can be sucked out to the tank bottom 21. It is arranged so as to enter the drawn suction well 23. When the LNG is discharged and the liquid level in the tank reaches the minimum level, the suction well 23 tilts the hull forward or backward in the front-rear direction X to collect the liquid, and the remaining liquid in the tank. In order to reduce the number of the center O, it is usually arranged at a position closer to the front and rear as far as possible from the position of the center O. FIG. 1 shows an example of the rear arrangement.
[0022]
As a result, as described later, sloshing that occurs from the front of the tank to the direction of arrow X ₂ is increased. Therefore, conventionally, a water control partition for preventing this has been provided as described above. When the discharge pipes 34, 35 are replaced by the connecting pipes 5 instead of the guide pipes 31, 32, the lower support member 7a shown in FIG. 1 is replaced with the oil pumps 34a, 34b. At a position above the
[0023]
According to the above-described piping device, a drag F, which is a pressure resistance based on the shape of the piping device, is applied to the piping device by sloshing, but the guide tubes 31 and 32 are connected by the connecting plate 5, Since the secondary moment of area Iy around the Y-axis is sufficiently large with respect to the bending moment caused by the drag F, the strength of the structure is increased by increasing the section modulus of the structure, and the bending stress is reduced to a low value. And bending can be increased to reduce bending.
[0024]
When the distance d between the coupling plates 5 is large, when a bending moment is applied to the composite member including the guide tube and the coupling plate, the coupling plate may be compressed and buckled in the Z direction. Since the auxiliary plate 6 is extended from the intermediate position Q in the Y direction and the sectional moment of inertia Ix with respect to the X axis is set to a certain value to secure the bending rigidity, the occurrence of such a problem is reliably prevented. be able to.
[0025]
Note has been described sloshing forces X ₂ direction in the above, sloshing in X ₁ and Y directions is generated. However, X ₂ direction sloshing becomes mainly with caused by surge is around shaking of the hull, long distance from the tip 24 of the tank to the position of the tube support structure, a long approach distance of motion the liquid correspondingly Therefore, while the influence of the flow rate of the LNG increases at the position of the piping device, the sloshing in the other direction does not have such a condition, and the effect does not cause much problem.
[0026]
Therefore, in the pipe system of the present example, the primary structure as well as to withstand directly the X ₂ direction sloshing, the small diameter tube and the wire to be behind the back and the pipe 31 of the auxiliary plate 6 so that there is no influence of sloshing Since they are arranged at appropriate positions, they can be reliably protected against sloshing. Also, since the discharge pipes 34 and 35 of the oil filling pump are attached via the flange 61 to the auxiliary plate 6 which can withstand sloshing as an integral structure, the number of attachment bands 9 is sufficient and strong. Thus, the structure can surely endure sloshing.
[0027]
The piping apparatus of the present embodiment capable of coping with the drag due to the sloshing described above utilizes the originally required guide tubes 31 and 32 as they are, connects them with the connecting plate 5, and reinforces them in a cross shape from now on. Since it is a structure in which the plate is merely extended, the structure is extremely simple, easy to manufacture, and requires a small amount of additional material.
[0028]
In particular, for a small cylinder tank such as a coastal LNG ship, a large-scale device such as a pipe tower structure is relatively expensive, but such a problem is solved. In addition, a large water barrier that is provided in place of the pipe tower and has many structural problems can be eliminated.
[0029]
In this example, the guide pipes 31 and 32 of the float type liquid level meter were used as the two large-diameter pipes constituting the piping device, but one of the two normally provided level gauges has a capacitance. When it is of a type that does not require the provision of a large-diameter guide tube by a method or the like, a large-diameter tube among the tubes 3 such as the liquid supply tube 33 and the discharge tube 34 or 35 is used. In this case, the diameter and thickness of the tube may be increased as necessary. When the liquid supply pipe and the discharge pipe are larger or about the same diameter as the guide pipe, these pipes can be used as two pipes instead of the guide pipe.
[0030]
FIG. 4 shows another example of the piping device to which the present invention is applied.
In the piping device of (a), the reinforcing plate 11 is connected to at least one guide tube 31 provided in this example as only one tube, and the liquid supply tube 33, which is the other of the plurality of tubes, and the load The discharge pipe 34, the spray liquid discharge pipe 36, the stirring pipe 37, the spray pipe 38, etc. of the oil pump 34a, and the electric wire 40 are attached to the reinforcing plate 11. A flange 11a, which is fixed to the upper and lower support members 7b and 7a shown in FIG.
[0031]
In the case where the number of pipes constituting the piping device is small, a structure having such a simple structure is employed without employing a structure in which the coupling plate 5 and the auxiliary plate 6 are combined as a reinforcing plate as in the piping device of FIG. It can be a flanged reinforcing plate. Even with this structure, a sufficient section modulus for the sloshing force can be obtained. With such a structure, the sloshing force itself in the X direction is reduced.
[0032]
In the piping device of (b), the reinforcing plate is formed as two connecting plates 5, 5 in which one guide pipe 31 and two discharge pipes 34, 35 of the oil pump are connected in a forked manner. The tubes 36 to 38 and the electric wires 40 are attached in the same manner as described above. According to this structure, the small diameter pipe and the electric wire are more safely protected from the sloshing force.
[0033]
In the above description, the case where the piping device of the present invention is installed in an LNG cylinder tank mounted on a coastal LNG ship has been described. However, an LPG cylinder tank, a spherical tank of an ordinary LNG ship, and oil and water etc. The piping device of the present invention can be applied to a tank of a carrier. For example, in the case of an ocean-going LNG ship, the diameter of the spherical tank is about 40 m, so the length of the pipe to be provided becomes longer. However, the oil pump is located at the center of the tank, and the influence of the sloshing force on the piping device is reduced. Therefore, the cross-shaped tube support structure or the like of the present invention can be adopted.
[0034]
【The invention's effect】
As described above, according to the present invention, in the first aspect of the present invention, a reinforcing plate for reinforcing a pipe is connected to two pipes of a plurality of pipes so that the pipe can resist the sloshing force. At the same time, other pipes of the plurality of pipes except for the two pipes are attached to the reinforcing plate, so that the reinforcing plate is connected to the pipes to form an integral structure, thereby reducing the sloshing force. In order to give the required bending strength to the structure in the direction, the section modulus is increased, and in a tank equipped with a liquid containing a liquefied gas such as LNG or LPG, the piping device sufficiently withstands the pressure resistance applied by sloshing. Structure.
[0035]
And since other pipes are attached to such a reinforcing plate, all pipes can be formed in a safe piping device integrated with the reinforcing plate.
[0036]
According to such a piping device, in order to impart the required strength to the structure with respect to any sloshing force, the cross-sectional dimension of the reinforcing plate may be determined so that the required cross-sectional coefficient is obtained. Therefore, this piping device can be easily applied to tanks of any shape and size.
[0037]
In addition, since the reinforcing plate has a connecting plate which is continuously connected between the two pipes at an interval and an overhanging plate which is joined to and protrudes from the connecting plate, liquefaction of LNG, LPG, etc. In a tank loaded with a gas-containing liquid, the piping arrangement can have a reasonable structure that can more reliably withstand the pressure resistance caused by sloshing of the liquid.
[0038]
That is, by connecting two pipes having a large diameter among a plurality of pipes with a connecting plate at intervals, when pressure resistance is applied to the piping apparatus in the front-rear direction and a bending moment is generated, the pipes are opposed to each other. Therefore, since the second moment of area is sufficiently increased to increase the section modulus and the bending rigidity, the bending stress can be made sufficiently smaller than the allowable stress and the deflection of the piping device can be reduced.
[0039]
In addition, since the overhanging plate that extends in the direction perpendicular to the front-rear direction is attached to the middle position of the coupling plate, it can withstand sloshing in the right-angle direction. Buckling due to compression bending occurring in the direction can be prevented. As a result, it is possible to make the pipe supporting structure sufficiently resistant to sloshing.
[0040]
The delivery apparatus of such a first aspect of the present invention, utilizing the existing two tubes, as well as coupled by coupling plates, only allowed overhang therefrom T-shaped or cross-shaped in overhang plate The structure is very simple, easy to manufacture and requires little additional material. Therefore, a large-scale pipe tower and a breakage-resistant partition wall which have conventionally been provided can be eliminated, and the pipe support structure can be greatly simplified and the cost can be sufficiently reduced.
[0041]
In the invention of claim 2 , the piping device is provided in a horizontal cylindrical liquefied gas tank, and two pipes thereof are provided at a position closer to one side from the center in the front-rear direction of the liquefied gas tank. Since most of the small diameter tube is mounted on the side opposite to the center side of the overhang plate, the small diameter tube can be more completely protected from the pressure resistance due to large sloshing.
[0042]
That is, since the pressure resistance due to sloshing becomes a magnitude corresponding to the flow velocity of the liquid, if the position of the two tubes is deviated in the length direction of the tank, the length from the longer side, that is, from the side opposite to one side, is increased. Although the sloshing increases and the sloshing in the opposite direction decreases, the sloshing on the larger side is received by a combination of the coupling plate and the overhanging plate, and the small-diameter pipe is arranged so as not to be affected by this large sloshing. Thus, at least most of the small diameter pipes can be more reliably protected from sloshing. In addition, it is possible to avoid large sloshing by arranging a part of the small-diameter pipe behind one of the two large-diameter pipes.
[0043]
Such a structure has a great practical effect as a simple and low-cost device in which a pipe tower and a water barrier are eliminated, especially for a small cylinder tank such as a coastal LNG ship.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of the overall configuration of a pipe support structure to which the present invention is applied and an LNG tank equipped with the pipe support structure. FIG. 1 (a) shows a longitudinal section of a tank including the pipe support structure, and FIG. 3 shows a cross-sectional state of a tube support structure portion.
FIGS. 2A and 2B are explanatory views showing a schematic structure of a tube support member portion, wherein FIGS. 2A and 2B show a vertical cross-sectional state, and FIG.
FIG. 3 is an explanatory view showing an arrangement state of a fuel oil pump.
FIGS. 4A and 4B are explanatory diagrams showing another configuration example of the piping device to which the present invention is applied.
FIGS. 5A and 5B are explanatory views of a schematic shape of a conventional LNG tank provided with a water barrier, and FIGS. 5A and 5B show longitudinal sectional states in a front-rear direction and a width direction, respectively.
[Explanation of symbols]
1 LNG carrier (liquefied gas carrier)
2 LNG tank (liquefied gas tank)
3 Multiple pipes 5 Coupling plate (coupling plate, reinforcing plate)
6 Auxiliary board (overhang board, reinforcement board)
11 Reinforcement plate 21 Tank bottom (bottom)
22 Tank top 31, 32 Guide tube (multiple tubes, two tubes)
33 Supply pipe (multiple pipes)
34, 35 Discharge tube (multiple tubes)
36 Liquid discharge tube for spray (multiple tubes)
37 Stirring tube (multiple tubes)
38 spray tubes (multiple tubes)
39 Gas sampling tubes (multiple tubes)
d Spacing 6F ₁ Back side (opposite side)
Q Intermediate position X Front-back direction (direction of force)
Y Direction perpendicular to the front-back direction

Claims (2)

In a piping device provided with a plurality of pipes including two pipes having a large diameter in a vertical direction and two or more pipes having a small diameter in a liquefied gas tank of a liquefied gas carrier in which sloshing occurs,
The plurality of pipes are provided so as to pass through the tank top from below the tank, and the two pipes are provided in parallel with each other in the vertical direction at an interval in the direction of the sloshing force. It is supported so as to receive a horizontal force at a position near the lower part and a position above a position near the tank top, and the two pipes are capable of resisting the force of the sloshing. A reinforcing plate for reinforcing the two tubes is combined, and the reinforcing plate is attached to the two tubes between at least a majority of upper and lower portions from the lower vicinity position to the upper position. From the joined position, the joining plate continuously joined to at least one of both surfaces of the joining plate at the middle position of the interval up to the same position as the joining plate in the vertical direction. Almost perpendicular to the direction of force At least one a structure having a protruding plate provided with protruding on the side, the other tubes except the two pipes of the plurality of tubes attached to said reinforcing plate, pipe and wherein the the. The tank is a horizontal cylindrical liquefied gas tank, and the plurality of pipes are provided at positions closer to one side from a center of the liquefied gas tank in the direction of the force, and a pipe having a small diameter among the plurality of pipes 2. The piping device according to claim 1 , wherein a large part of the plunger is mounted on a side opposite to the center side of the overhang plate. 3.

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