JPH0615821Y2 - Low temperature liquefied gas ship - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a low temperature liquefied gas ship, and relates to a low temperature liquefied gas ship that prevents a temperature drop of a flexible joint provided in a dome mating portion of a storage tank. Is.

[Prior Art] Generally, a low-temperature liquefied gas ship that accommodates and conveys a low-temperature liquefied gas such as LNG, LPG, ethylene, and ammonia is one or a plurality of low-temperature liquefied ships provided in a hull as shown in FIG. A liquefied gas storage tank a is provided. A cross section of this low temperature liquefied gas ship is shown in FIG. The storage tank a is covered with a cold insulating material, and the inside thereof is -162 ° C when the low-temperature liquefied gas to be stored is LNG, -45 ° C in the LPG,
It is kept at a low temperature of -104 ° C for ethylene and -33 ° C for ammonia.

The storage tank a is accommodated in the hull b so that it can be contracted and moved. Therefore, when the low-temperature liquefied gas is stored in the storage tank a, the storage tank a is thermally shrunk and the hull b
Since there is no thermal deformation, the storage tank a and the hull shell b move relative to each other.

Now, it is necessary to allow the above-mentioned relative movement at the mating portion of the dome of the storage tank and the hull of the storage tank, which is provided for loading and unloading the low temperature liquid in the storage tank.

Conventionally, as shown in FIG. 4, the dome g of the storage tank a
Is projected from the deck of hull b and its dome g
The folded part e was formed on the deck around the, and the flexible joint f made of synthetic rubber was joined between the tank dome top plate d on the top of the dome g and the folded part e.

With such a structure, even if the hull shell b and the storage tank a move relative to each other due to a temperature difference and the gap between the dome top plate d and the folded portion e changes, the flexible joint f allows the change. The part does not need to be deformed.

[Problems to be Solved by the Invention] By the way, synthetic rubber, which is a material of the flexible joint f, is generally vulnerable to low temperature and hardens at about -40 ° C or lower.
Therefore, it has been proposed to prevent the flexible joint from being directly cooled by the low temperature liquid by sandwiching a heat insulating packing between the tank dome top plate d and the flexible joint f on the side of the storage tank a which becomes low temperature. .

However, since the flexible joint f is directly exposed to the outside air, even if the flexible joint f is thermally insulated from the storage tank a, for example, when traveling in a cold region where the outside air becomes 0 ° C. or less, for example, L
The temperature of the flexible joint may fall below -40 ° C on NG ships. Therefore, there is a problem that the flexible joint becomes stiff and cannot serve as a flexible joint, and at the upper and lower ends, elasticity is lost and sealability is significantly impaired.

Although it is possible to make a flexible joint from a material resistant to low temperature, there is a problem that the material that can withstand a temperature lower than -40 ° C is limited and the manufacturing cost of the low temperature liquefied gas ship becomes high.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a low-temperature liquefied gas ship capable of preventing the temperature drop of the flexible joint made of synthetic rubber provided in the accommodation tank joint even in cold regions. To provide.

[Means for Solving the Problems] In order to achieve the above object, the low temperature liquefied gas ship of the present invention is
Inside the hull defined by the deck, bottom plate, side plates and end walls, there is provided a tank which is covered with a cold insulating material at a predetermined interval and which substantially stores the low temperature liquid, and the dome of the tank is projected from the hull deck. The dome top plate is provided on the top of the dome and the folded portion is formed on the ship deck around the dome, and between the dome top plate and the folded portion,
In a low temperature liquefied gas ship formed by joining flexible joints made of synthetic rubber such as neoprene rubber for surrounding the dome while permitting relative movement of the tank and the hull, the hull deck outside the flexible joints. A heating pipe is arranged on the folded portion so as to surround the flexible joint, and the heating pipe is connected to the hot air supply device and at the inner circumference of the heating pipe, the warm air is directed upward toward the flexible joint. Is provided with a large number of injection holes.

[Operation] According to the above configuration, when sailing in a cold region or the like, hot air is supplied from the hot air supply device to the heating pipe, and the hot air is blown from the injection holes to the flexible joint. Good flexibility is maintained. In addition, since the warm air from the injection hole of the heating pipe is blown upward toward the flexible joint and rises so as to surround the flexible joint, the flexible joint is more effectively protected from cold outside air. It Furthermore, since a heating pipe is installed at the folded part of the hull deck to which the lower end of the flexible joint is connected, even if the deck is cold due to outside air,
The folded portion to which the lower end of the flexible joint is connected can be directly heated by the heat of the heating pipe itself by heat conduction. Further, since the upper end of the flexible joint is heated by the warm air that also rises around the dome top plate, it is not cooled by heat conduction. Thereby, the elasticity of the upper and lower ends of the flexible joint is kept good, and the good sealability of the joint is maintained.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partial cross-sectional view showing an engagement portion between a storage tank and a hull of a low temperature liquefied gas ship according to an embodiment of the present invention.
In the figure, 1 is a storage tank, 2 is a ship deck, and a folded portion 8 is provided so that the dome 4 of the storage tank 1 projects above the deck 2.
Is formed.

The dome top plate 3 is provided on the top of the dome 4, and the folded portion 8 between the dome top plate 3 and the hull deck 2 is provided.
A flexible joint 5 made of a synthetic rubber such as neoprene is joined between and. That is, the lower end 5b of the flexible joint 5 is
The folding member 8 is airtightly attached to the dome top plate 3 by the attachment member 9, and the upper end 5a is also airtightly joined to the dome top plate 3 by the attachment member 9. As a result, the void space 10 between the hull deck 2 and the storage tank 1 is satisfactorily shielded from the outside air by the flexible joint 5.

By the way, the folded-back portion 8 of the hull deck 2 is arranged so that the heating pipe 6 for introducing the warm air surrounds the outside of the flexible joint 5.
Installed on top. As shown in the schematic plan view of FIG. 2, the heating pipe 6 surrounds the flexible joint 5 and has a large number of injection holes 7 provided at predetermined intervals so as to blow warm air to the flexible joint 5. And is connected to a warm air supply device (not shown). The injection hole 7 is formed in the inner circumference of the heating pipe 6 so as to blow upward toward the flexible joint 5 as shown in FIG.

Except for the above-mentioned connection part and warm air supply device, it has the same structure as the conventional low temperature liquefied gas ship shown in FIGS. 3 and 4.

Next, the operation of this embodiment will be described.

When the low temperature liquefied gas ship according to the present embodiment travels in a cold region and the temperature of the flexible joint 5 is likely to drop to about -40 ° C or lower, the hot air supply device is driven. Then, the heating pipe 6
The warm air introduced into the inside is blown upward toward the flexible joint 5 from the injection holes 7 opened at a predetermined interval. In this way, the flexible joint 5 is effectively heated while being shielded from the outside air by the air curtain effect by blowing hot air, and is prevented from a temperature drop, and its flexibility is maintained.

Further, the upper and lower ends 5a and 5b of the flexible joint 5 are connected to the dome top plate 3 and the folded portion 8, and these are at the outside air temperature, and the upper and lower ends 5a and 5b are cooled to the outside air temperature by heat transfer. Although it becomes easier, at the lower end 5b, the heating pipe 6 is installed in the folded portion 8, and the heat of the heating pipe 6 heats the lower end 5b through the folded portion 8, and at the upper end 5a. Since the warm air is blown upward to heat the outer peripheral edge of the dome top plate 3, the upper end 5a
Are prevented from being cooled by the outside air. Therefore, since the upper and lower ends 5a and 5b of the flexible joint 5 can maintain good elasticity, the sealing at the joint surface is good and the airtightness of the void space 10 is kept good.

As the warm air, dry air containing no moisture, dry nitrogen, or the like is suitable, but the hot air is not limited to this, and any one that can heat the flexible joint 5 may be adopted.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects are exhibited.

(1) When navigating in cold regions, the hot air supply device supplies warm air to the heating pipe, and the hot air is blown from the injection holes to the flexible joint to improve the flexibility of the flexible joint. Maintained.

(2) Therefore, restrictions on the operating area of low temperature liquefied gas ships, especially LNG ships, are removed, and it is possible to operate in cold regions.

(3) Since the warm air from the injection hole of the heating pipe is blown upward toward the flexible joint and rises so as to surround the flexible joint, the flexible joint is more effectively protected from cold outside air. To be done.

(4) Since the heating pipe is installed at the folded portion of the deck of the ship, the heat of the heating pipe itself will conduct heat through the folded portion at the lower end of the flexible joint even if the deck is cold due to outside air. Since the upper end of the flexible joint is heated by the warm air that also rises around the dome top plate, it is not cooled. Therefore, the elasticity of the upper and lower ends of the flexible joint is kept good, and the good sealability of the joint is kept good.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a joint between a storage tank and a hull of a low temperature liquefied gas ship according to an embodiment of the present invention, and FIG. 2 is a schematic plan view of the joint shown in FIG. 3 and 4 are a schematic configuration diagram and a cross-sectional view of a conventional low temperature liquefied gas ship, respectively. In the figure, 1 is a storage tank, 2 is a ship deck, 5 is a flexible joint,
6 is a heating pipe.

Claims (1)

[Scope of utility model registration request] 1. A tank for covering a cryogenic liquid, which is covered with a cold insulating material at a predetermined interval, is provided in a hull defined by a deck, a bottom plate, a side plate and an end wall, and a dome of the tank. The dome top plate is provided on the top of the dome and is provided so as to project from the hull deck, and the folded portion is formed on the hull deck around the dome, and the relative movement of the tank and the hull between the dome top plate and the folded portion is performed. In a low temperature liquefied gas ship formed by joining flexible joints made of synthetic rubber such as neoprene rubber for surrounding the dome while allowing, on the folded portion of the hull deck outside the flexible joints,
A heating pipe is arranged so as to surround the flexible joint, the heating pipe is connected to a hot air supply device, and a large number of hot air blown upward toward the flexible joint is provided on the inner circumference of the heating pipe. A low-temperature liquefied gas ship characterized by having an injection hole.