JPS594874Y2 - Tank structure of liquefied natural gas carrier - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tank structure for a liquefied natural gas carrier.

As shown in Fig. 1, a conventional liquefied natural gas carrier has dams 5, 6, and 7 formed between an upper deck 1 and an inner deck 2, between parallel bulkheads 3, and between a double bottom wall 4. In addition, there is also a Kotsufadam between the outer panel and the longitudinal bulkhead.
Or side tanks), and multiple holds were formed in the bow and stern directions.

Inside each hold, there is a secondary heat insulation box 8 made of perlite, plywood, etc., a secondary heat insulation wall (membrane 36% Ni steel) 9 located inside it, and a primary heat insulation box 10 located inside it, A membrane type tank 12 was constituted by a primary heat insulating wall 11 located inside the tank.

The biggest weakness of such a tank 12 is the heat insulation walls 9, 11.
This means that it is vulnerable to sloshing because of its low rigidity.

This sloshing is caused by the movement of the liquefied natural gas 14 in the tank chamber 13 due to the movement of the ship, colliding with the top surface and side surface of the primary heat insulation wall 11, and the large pressure caused by the movement of the liquefied natural gas 14 in the tank chamber 13 causes the heat insulation wall 9.
1 and the heat insulation boxes 8 and 10.

In particular, when the motion of the ship and the motion of the liquefied natural gas 14 are synchronized, the sloshing pressure increases.

The present invention proposes a tank structure for a liquefied natural gas carrier that can solve the above problems, and one embodiment thereof will be described below with reference to FIGS. 2 to 8.

In FIGS. 2 and 3, the same reference numerals as in the conventional example (FIG. 1) indicate the same or almost the same components.

In other words, 1 is the upper deck, 2 is the inner deck,
3 is a transverse bulkhead, 4 is a double bottom wall, 5,6゜7 is a kotsufadam, 8 is a secondary heat insulation box, 9 is a secondary heat insulation wall, 10 is a primary heat insulation box, 11 is a primary heat insulation wall, 12 is a tank, 13 is the tank room,
No. 14 does not indicate liquefied natural gas.

Further, numeral 15 indicates a bottom dam formed by an outer panel 16 and a vertical partition wall 17.

In the present invention, a water control plate 18 that extends from the top of the tank 12 through both heat-insulating walls 9 and 11, which are membrane materials, and projects to the upper part of the tank chamber 13, is suspended from the inner deck 2, which is an inner shell material. There is.

This water control plate 18 extends over the entire length in the ship's direction.

The details of the installation and structure will be described below. As shown in Figures 4 to 8, upper deck 1 and inner deck 2
are connected and reinforced by a floor plate 35.

To attach the water control plate 18, a considerable portion of the heat insulating walls 9, 11 is removed, and the heat insulating boxes 8, 10 in the vicinity thereof are also removed.

The water control plate 18 made of a 9% Ni steel plate includes a top plate 19, a pair of left and right water control inclined plates 20 that are connected to each other so as to be inclined inward from the vicinity of both ends of the top plate 19, and these water control inclined plates 20. The lower plate 21 connected between the lower ends and the inclined top plate 19A formed to match the shape of the inner shell form a closed trapezoidal box shape, and the interior thereof is further provided with floor plates 22 at appropriate intervals in the longitudinal direction. A drain hole 23 is formed at the lower corner of the floor plate 22.

The top plate 19 overhangs from the water utilization slope plate 20 in the bow and aft direction, and has a large number of through holes 24 in the overhang.
is provided.

A pair of liners 25 made of 9% Ni steel plates are fixed to the lower surface of the inner fishing rod 2 by welding or the like, and the liners 25 are made of 9% Ni steel plates and extend along the entire length in the direction of the ship.

Note that the corner portion may be divided as shown in FIG. 8 depending on the inner shell structure.

A heat insulating material 26 made of phenol resin or the like is fixed between both liners 25.

Threaded holes that match the through holes 24 are formed from the heat insulators 26 to the liner 25.
The 6th side may be a through hole.

Therefore, by inserting the stud bolt 27 into the liner 25 side, passing the through hole 24 through the downward protruding portion of the stud bolt 27, and tightening it from below with the nut 28, the water control plate 18 can be assembled with its top plate 19 against the heat insulating material 26. It is fixed to the inner deck 2 side with the

The water-tight connection between the heat-insulating wall 9 and the water-control plate 18 is achieved by attaching an upper fixing plate 30 made of 9% Ni steel plate to the outer surface of the flat-structured inclined water usage plate 20 via a plurality of brackets 29. are fixed by welding etc., and this upper fixing plate 3
The end of the heat insulating wall 9 is applied to the bottom surface of the heat shield wall 9 and fixed by welding or the like, and the lower fixing plate 31 made of a 9% Ni steel plate formed into an L shape is fixed to the water utilization inclined plate 20 by welding or the like. At the same time, it is fixed to the lower surface of the end of the heat insulating wall 9 by welding or the like.

Note that the heat insulating wall 11 is also attached in the same manner.

The heat insulating box 8.10 has been removed around the water control plate 18, and since the structure is uneven, a soft heat insulating material 32 such as polyurethane foam is filled here.

As described above, the water control plate 18 is made of a 9% Ni steel plate and is provided with a floor plate 22 or a bracket, thereby providing a strong structure that can withstand the low temperature and the oscillating pressure of the liquefied natural gas 14.

Moreover, the drain hole 23 allows the interior of the water control plate 18 to be drained well.

In the above configuration, the liquefied natural gas 14 is
When oscillation occurs, the oscillation is caught and eliminated by the water control plate 18, and the sloshing pressure becomes minimal.

In the case of the conventional membrane system, as shown in Figure 2, the liquid level relative to the tank chamber height H is set at h = 90%H or h - 98%H to prevent sloshing. (h=50%H) etc., but as mentioned above, by providing the water control plate 1B to eliminate sloshing pressure and further adjusting its protrusion, it is possible to achieve h=70%H or h-50%H. Pretty much any liquid level can be used, such as %H.

In the above embodiment, the water control plate 18 has one long strip in the direction of the ship, but it may have two strips or a plurality of strips as shown in FIG. 9.

Further, in this embodiment, the main focus was on solving pitching motion, but in order to eliminate sloshing during rolling motion, a long water control plate 18 may be provided in the bow and stern direction, or water use plates 18 in both directions may be combined.

In addition, as the water control plate 18, as shown in FIG.
1 is removed, the lower part is opened 33, and the inclined plate 2 for water control is installed.
Any number of through holes 34 may be provided at any arbitrary position of the ship.As described in the embodiments, according to the present invention, by providing a water control plate, it is possible to reduce the oscillation of the liquid natural gas that occurs during the movement of the ship. , sloshing can be minimized and damage to heat insulating boxes and heat insulating walls caused by sloshing pressure can be prevented.

Furthermore, by adjusting the depth of the water utilization plate, it is possible to transport at any desired liquid level.

In addition, since the water control plate is installed vertically from the side with the inner shell, sufficient strength to absorb vibrations can be ensured.

Furthermore, since the water control plate is installed vertically from the inner shell material, the entire tank can have a membrane structure.

Furthermore, since a heat insulating material is interposed between the water control plate and the inner shell material, low temperatures are not transmitted to the hull, and therefore the water control plate can be firmly held without affecting the strength of the hull.

[Brief explanation of the drawing]

Fig. 1 is a vertical side view showing a conventional example, Figs. 2 to 8 show an embodiment of the present invention, Fig. 2 is a longitudinal side view, and Fig. 3 is a sectional view taken along line A-A in Fig. 2. , Fig. 4 is a longitudinal sectional side view of the main part, Fig. 5 is a BB sectional view in Fig. 4, Fig. 6 is an enlarged view of the C section, Fig. 7 is an enlarged view of the same part, and Fig. 8 is an enlarged view of the same part. A developed perspective view of section E in FIG. 3, FIGS. 9 and 10 respectively show different embodiments, FIG. 9 is a vertical side view, and FIG. 10 is a vertical side view of the main part. 1...Upper stick, 2...Inner stick (inner shell material), 8...Secondary heat insulation box, 9...Secondary heat insulation wall (membrane material), 10...-Secondary heat insulation box, 11...
Primary heat insulation wall (membrane material), 12...tank, 13
... Tank room, 14 ... Liquefied natural gas, 18 ...
Water control plate, 19... Top plate, 20... Slanted water control plate, 2
5... Liner, 26... Heat insulating material, 30... Upper fixing plate, 31... Lower fixing plate, 32... Soft heat insulating material.

Claims (1)

[Scope of utility model registration request] In a membrane-type tank for a liquefied natural gas carrier, a water control plate that penetrates the membrane material from the top of the tank and projects to the upper part of the tank chamber is installed vertically from the inner shell material, and a water control plate is provided between the water control plate and the inner shell material. A tank structure for a liquefied natural gas carrier, characterized by having a heat insulating material interposed therein.