JPH0999996A - Tank sloshing reduction device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To effectively reduce sloshing occurring in a rectangular tank in a limited narrow range. SOLUTION: A liquid level disturbing tool 3 for disturbing the flow surface of a stored liquid 2 is attached to both ends in the width direction at the upper end position of the inner side surface of each tank side plate 1a constituting a rectangular tank 1. The liquid level disturbing device 3 has an inverted triangular central plate 4 and left and right plates 5 and 6, and each plate 4, 5, 6
The plates 4, 5 and 6 are integrated by joining the one side portion at an acute angle. The left and right plates 5 and 6 have a hole in the center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tank sloshing reduction device used for reducing a sloshing phenomenon of a liquid surface which occurs when a large tank swings.

[0002]

2. Description of the Related Art For example, in a tank (cargo tank) mounted on a ship such as an LNG ship, when the hull violently shakes under the influence of waves or the like during navigation, a flow occurs in the stored liquid, so-called sloshing. It is known that phenomena occur. It is also known that the sloshing phenomenon occurs in the above-ground tanks and underground tanks due to vibration such as an earthquake. Such a sloshing phenomenon occurs due to the swinging of the tank a in the direction of the arrow as shown in the outline of FIG.
The liquid level of the stored liquid b in the inside will be periodically repeated from the static state shown by the solid line to the fluctuating state shown by the alternate long and short dash line and the dotted line.
As a result, the stored liquid b collides with the ceiling of the tank a and locally causes a large impact force. Particularly, in the case of a rectangular tank, the ceiling plate corresponding to the tank corner portion where the tank side plates intersect due to sloshing tends to be locally most susceptible to breakage.

As a measure for reducing the above-mentioned sloshing phenomenon, conventionally, as shown in FIG. 6, a partition plate c is vertically and horizontally arranged inside a tank a and combined in a grid pattern so as to partition the vibration energy of the stored liquid b. A method is known in which the collision with the plate c is absorbed to suppress sloshing.

[0004]

However, in the case of the above conventional sloshing reduction measures in which the partition plates c are arranged vertically and horizontally inside the tank a, the shaking energy of the stored liquid b due to the collision between the partition plates c and the stored liquid b. Although sloshing can be effectively suppressed by absorbing the material, since the partition plate c combined in the shape of a cross girder is a large-scale structure, the material of the partition plate c and the labor and work time required for installation work Is large, and the total weight of the plurality of partition plates c is large.
If it is applied to a tank mounted on a ship such as an NG ship, there is a problem that the maximum load of the ship is reduced.

Therefore, the present invention is intended to provide a tank sloshing reduction device capable of suppressing the increase in weight of the tank to a minimum and effectively reducing sloshing in a limited narrow range. Is.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an inverted triangular central plate and a central plate at the upper end positions of the tank side plates near the tank corners where the tank side plates intersect. A liquid level disturbing device is formed by joining left and right plates each having a hole at one side portion at an acute angle, and is mounted so that the joining portion extends upward inward and the upper surface side is released. .

When the stored liquid flows due to sloshing due to the rocking of the tank and the stored liquid is pushed toward the position of the liquid level disturbing device, the stored liquid is distributed left and right by the left and right plates and is swept in the opposite direction. , Part flows into the holes in the left and right plates. Therefore, the liquid level of the stored liquid is disturbed, and the periodicity of sloshing is weakened.
Since the liquid surface disturbing device is attached near the tank corner, sloshing can be effectively reduced in a narrow range.

Further, instead of attaching the liquid level disturbing tool at the upper end position of the tank side plate near the tank corner where the tank side plates intersect, the liquid level disturbing tool is provided adjacent to the tank side plates with the tank corners sandwiched therebetween. It may be configured to be attached to the corner of the tank so as to straddle between them.
Since the left and right plates will straddle between the tank side plates adjacent to each other, the role of reinforcing the tank can be exerted.

Further, the left and right plates of the liquid surface disturbing device can be constructed as curved plates which are smoothly curved so that the surface is dented, whereby the stored liquid rushed to the surface is swept in the opposite direction. Is smoothly performed along the curved surface of the bending plate, and sloshing can be reduced more effectively.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

1 (a), 2 (b), (b), (c), and (d).
1 shows an embodiment of the present invention, and shows an example of application to a rectangular tank 1 for liquid storage mounted on a ship such as an LNG ship.

In the present invention, the tank 1 is constructed by focusing on the fact that the portion that is easily destroyed by the collision of the stored liquid due to sloshing is the ceiling plate above the tank corner where the tank side plates 1a intersect, which is a limited narrow range. An inverted triangular central plate 4 and left and right plates 5 and 6 are joined at one side edge at an acute angle to both ends in the width direction of the tank side plate 1a, which are close to the tank corner at the upper end of the inner side surface. The liquid surface disturbing device 3 is formed so that the joint portion extends inward and upward and the upper surface side is released.

The above liquid level disturbing device 3 is shown in FIGS.
As shown in detail in (C) and (D), the inverted triangular central plate 4 is arranged so that the apex of the triangle faces downward.
And the left and right plates 5 and 6 in the shape of an inverted triangle having a hole 7 in the center and arranged so that the apex of the triangle faces downward like the center plate 4. The plates 5 and 6 are combined in a plane V shape so that their one side edges are in contact with each other, and the contact angles of the left and right plates 5 and 6 are bisected inside the left and right plates 5 and 6. As described above, one side portion of the central plate 4 is disposed in contact with each other, and the contact portions of the plates 4, 5, 6 are integrally joined, and the other side portions of the plates 4, 5, 6 are connected to each other. The tank side plate 1a is fixed to the inner surface so as to be positioned in the same vertical plane.

When the tank 1 swings due to the hull motion and sloshing occurs in the liquid storage 2 while the ship is sailing at sea, the liquid storage 2 is stored in the upper end portion of the tank side plate 1a as shown by the alternate long and short dash line and the dotted line in FIG. Although it is rushing toward the side, the stored liquid 2 rushing near each tank corner at this time
Is to be disturbed by the liquid level disturbing tool 3 attached near each tank corner. In this case, the stored liquid 2 that has flowed over is (a) and (b) in FIG.
(C) As shown in (d), the liquid is disturbed along the left and right plates 5 and 6 of the liquid surface disturbing device 3 so as to be distributed to the left and right, and the reverse slope of the left and right plates 5 and 6 is provided. Due to the action of, the liquid will be washed away in the direction opposite to the direction that it is pushed in. Further, at this time, part of the stored liquid 2 is pushed upward through the holes 7 provided in the left and right plates 5 and 6. I will stick to it. Therefore, since the liquid level of the stored liquid 2 is disturbed, the periodicity of sloshing can be weakened and sloshing can be reduced.

In the above, the liquid level disturbing tool 3 does not give a great resistance to the flow of the stored liquid 2 due to sloshing and significantly disperses the flow, so that an excessive force is exerted on the liquid level disturbing tool 3 itself. In addition, since the liquid level disturbing tool 3 is a lightweight, small-scale structure composed of only the left and right plates 5, 6 and the central plate 4, the maximum loading load of the ship can be reduced. It is not significantly reduced, and the structure is extremely simple, so that it is easy to manufacture and install. Further, since the liquid level disturbing device 3 is attached only near the tank corner portion in correspondence with the ceiling plate above the tank corner portion where the tank 1 is most likely to be destroyed by sloshing of the tank 1, it is effective with a small number of points. There is an advantage that sloshing can be reduced.

Next, FIG. 3 shows another embodiment of the present invention. The tank side plate 1a of the rectangular tank 1 shown in FIGS. 1 and 2 (a), (b), (c) and (d). Instead of mounting the liquid level disturbing tool 3 near each of the tank corners at the position of the upper end of the inner surface of the tank, the tank side plate 1a may be straddled at the upper end of the inner surface of the four corners of the tank 1. The liquid level disturbing tool 3 is attached to the.
In the present embodiment, each plate 4, 5, 6 of the liquid surface disturbing device 3 is formed in a size corresponding to the angle of the tank corner portion.

In the case of the embodiment shown in FIG. 3, sloshing can be reduced with a smaller number of parts than in the case of the embodiment shown in FIGS. 1 and 2 (a), (b), (c) and (d). Moreover, since the liquid level disturbing tool 3 straddles the tank side plates 1a of the tank 1 which are adjacent to each other, the tank side plate 1 when the stored liquid 2 is pushed by sloshing
The function of a as a reinforcing material can also be imparted.

Next, FIG. 4 shows another example of the shape of the liquid surface disturbing tool 3, and the liquid surface disturbing tool 3 shown in each of the above embodiments.
In the same structure as described above, the left and right plates 5 and 6 are curved plates 5'and 6'which are smoothly curved so that the surface portions are recessed.

When the liquid level disturbing tool 3 shown in FIG. 4 is attached and used as shown in FIGS. 1 and 3, when sloshing occurs and the liquid level of the stored liquid 2 reaches the position of the liquid level disturbing tool 3. In addition, since the pushing back of the liquid reservoir 2 to the opposite side is smoothly performed along the curved surfaces of the left and right curved plates 5 ', 6',
Compared with the above-mentioned embodiment, sloshing can be reduced more effectively.

The present invention is not limited to the above-described embodiments. For example, in each of the above-described embodiments, as an example of a marine tank, a rectangular tank 1 mounted on a ship such as an LNG ship is used. Although the example of adoption is shown, it is needless to say that the same can be applied to the above-ground tank and the underground tank, and various changes can be made without departing from the scope of the present invention.

[0021]

As described above, the tank sloshing reduction device of the present invention exhibits the following excellent effects. (1) Since a liquid level disturbing device, which is a combination of an inverted triangular center plate and left and right plates with holes, was attached near the tank corner at the upper end of the inner side surface of the tank side plate, sloshing occurred. It is possible to distribute the stored liquid that has rushed in sometimes to the opposite direction by distributing it to the left and right with the left and right plates, and to make a part of the stored liquid flow into the holes in the left and right plates. The liquid surface of the liquid can be disturbed and sloshing can be reduced. (2) The liquid level disturbing device is installed only in a narrow area corresponding to the ceiling plate above the tank corner that is easily destroyed by the collision of the stored liquid due to sloshing, so it is effective in reducing sloshing with a small number of parts. Can be operated. (3) The liquid level disturbing device has an extremely simple structure and can be easily manufactured and installed.Also, the liquid level disturbing device is a lightweight and small-scale structure. Even if it is adopted for the tank installed, it does not affect the loading capacity of the ship. (4) By attaching the liquid level disturbing device to the tank corner portion, it is possible to add a function as a reinforcing material for the tank side plate. (5) By forming the left and right plates of the liquid surface disturbing device as curved plates, the stored liquid can be smoothly pushed back, and sloshing can be further effectively reduced.

[Brief description of drawings]

FIG. 1 is an overall schematic view showing an embodiment of a tank sloshing reduction device of the present invention.

FIG. 2 is a view showing a liquid surface disturbing device which is an essential part of the present invention,
(A) is a front view, (B) is a side view, (C) is a plan view,
(D) is a perspective view.

FIG. 3 is an overall schematic diagram showing another embodiment of the present invention.

FIG. 4 is a perspective view showing another example of the shape of the liquid surface disturbing device that is a main part of the present invention.

FIG. 5 is an explanatory diagram of a sloshing phenomenon.

FIG. 6 is a schematic view showing an example of conventional measures for reducing sloshing.

[Explanation of symbols]

 1 Tank 1a Tank side plate 2 Liquid storage 3 Liquid level disturbing tool 4 Center plate 5, 6 Plate 7 hole

Claims (3)

[Claims] 1. An inverted triangular center plate and left and right plates each having a hole in the center are formed at one side of the tank side plate at the upper end position of the tank side plate near the intersection of the tank side plates. A sloshing reduction device for a tank, characterized in that the liquid level disturbing device joined to each of the tanks is attached so that the joining portion projects upward inward and the upper surface side is released. 2. A liquid level disturbing tool is attached to an upper end position of the tank side plate near the tank corner where the tank side plates intersect, and the liquid level disturbing tool is adjacent to the tank side plate sandwiching the tank corner. The device for reducing sloshing of a tank according to claim 1, wherein the device is attached to the corner of the tank so as to straddle the space. 3. The tank sloshing reduction device according to claim 1 or 2, wherein the left and right plates of the liquid surface disturbing device are curved plates which are smoothly curved so that the surfaces are recessed.