JPS63279994A - Leaked liquid receiving structure for vertical and cylindrical liquified gas tank - Google Patents

Abstract

PURPOSE:To obtain a reliable leaked liquid receiving structure for vertical and cylindrical tank by adjoining the lower end portions of a liquid-proof sheet having inverse U-shaped cross-section and applied across a thermal insulation supporting member and a downwardly bent liquid-proof sheet applied onto the underface of a thermal insulation layer each other, and providing a trough thereunder. CONSTITUTION:A plurality of lateral supporting beams 4 are fixed onto a longitudinal supporting girders 3 fixed in parallel with proper interval on an inner bottom board 2 of a vessel to provide a supporting base. A vertical and cylindrical LNG tank 1 is mounted on the supporting base 5. A liquid-proof sheet 9 having counter U-shaped cross-section is mounted on the underface of the bottom board 9a of the tank 1 while stepping over a thermal insulation supporting member 6 with vertical section thereof being sandwiched by thermal insulation layers 10, 11 and projected through the underface. Another liquid-proof sheet 12 is applied onto the underface of an adjoining thermal insulation layer 11a with the opposite ends of the liquid-proof sheets 9, 12 adjoining downward each other, and a trough 13 is laid thereunder. Consequently, liquid leaked even through flat bottom face of the vertical and cylindrical LNG tank can be received.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a leakage catch structure for a vertical cylindrical liquefied gas tank.

[Conventional technology]

For example, in the case of a spherical tank on an LNG ship, if cracks occur for some reason and LNG leaks, if it drips onto the inner bottom plate, etc., it will cool down excessively and cause the ship to break down. Therefore, a leakage catch structure is provided.

Conventionally, this type of leakage catch structure has a spherical shape supported on an inner bottom plate 02 via a support skirt 07 and whose surface is covered with a heat-insulating layer 08, as shown in the vertical cross-sectional view of FIG. In tank 01, leaked LN is present in the upper hemisphere.
G is allowed to flow down along its outer surface, and a leakage receiver (not shown) is guided to the cell via an annular gutter and a drain vibe 015 installed around the equator, and the leaked LNG in the lower hemisphere is guided to its heat shield. It is known that the leakage liquid is caused to flow down along the layer 08 and is led from the vicinity of the lowest point of the central part to the cell through a drain pipe 014 to a leakage receiver (not shown).

However, although a spherical tank is fine in terms of structure, a vertical cylindrical liquefied gas tank has its bottom surfaces parallel to each other in the front and back direction at appropriate intervals in the left and right direction.
the impossibility of forming a continuous liquid-proof thermal barrier layer due to contact with a plurality of extending support beams;
Also, since the bottom surface is flat over a wide area, it is difficult to allow leakage liquid to flow down to the central part, so it cannot be applied.

[Problem that the invention seeks to solve]

The present invention was proposed in view of these circumstances, and
The purpose of the vertical cylindrical liquefied gas tank leak catcher is to provide a structure that can be applied to tanks with a flat bottom and in contact with multiple support beams.

[Means for solving the gap m4] For this purpose, the present invention is supported on a plurality of support beams extending in parallel with each other via heat insulating support members extending in the same direction, and the pond portion is covered with a heat insulating layer. The structure of the leakage catcher of a vertical cylindrical liquefied gas tank having a bottom plate covered with is such that the center part of the upper end is inserted between the above-mentioned heat-insulating support material and the lower surface of the bottom plate, and both ends straddle the above-mentioned heat-insulating support material. a liquid-proof sheet having an inverted U-shaped cross section that is curved downward and whose lower edge slightly protrudes from the lower surface of the heat-insulating layer;
Liquid-proofing sheets with downward flanges on both substantially horizontal ends that extend close to the bottom ends of the inverted U-shaped liquid-proof sheet, each of which is attached to the lower surface of the thermal-insulating layer adjacent to the thermal-insulating layer and curves downward. It is characterized by comprising a sheet, and a plurality of gutters installed directly under the lower end of each of the inverted U-shaped liquid-proof sheets and the lower ends of the liquid-proof sheets with downward flanges at both ends adjacent thereto, and extending parallel to the support beams. shall be.

[Effect]

With the above-described configuration, the liquid leakage receiver can be collected into the tank without leaking liquid from the bottom plate of the vertical cylindrical liquefied gas tank downward.

〔Example〕

An embodiment in which the present invention is applied to an LNG ship will be described with reference to the drawings. FIG. 1 is an overall longitudinal sectional view thereof, and FIG. 2 is a partially enlarged view showing section H in FIG. 1.

First, in Fig. 1, l indicates a plurality of longitudinal support girders 3 installed in parallel at appropriate intervals in the left-right direction on the inner bottom plate 2 of the LNG carrier, and a plurality of longitudinal support girders 3 installed in parallel at appropriate intervals in the longitudinal direction on top of these. This is a vertical solid cylindrical LNG tank that is placed on a tank support stand 5, which is made up of a plurality of lateral support beams 4 attached to The solid cylindrical LNG tank l has an anchor ring 7 to prevent the ship from moving.
is supported by the inner bottom plate 2, and its outer surface is covered with a heat-insulating layer 8.

Next, in FIG. 2, numeral 9 is placed on the lower surface of the tank bottom plate 9a in an inverted U-shape so as to straddle the heat insulating support member 6, and its vertical portion is closely covered from the front and back by the heat insulating layer 10.11. A liquid-proof sheet having an inverted U-shaped cross section with its lower end protruding from the lower surface of the heat-insulating layer 10.11;
2 is attached to the lower surface of the heat-insulating layer tSa that is in close contact with the front side of the heat-insulating layer 100, and its front and rear ends extend close to the lower ends of the adjacent inverted U-shaped liquid-proof sheets 9, 9, and each has a downwardly curved edge. 13 is a gutter extending in the left-right direction directly below the lower end of the adjacent inverted U-shaped liquid-proof sheet 12 with downward flanges at both ends, and the end of the gutter 13 is a drain pipe (not shown). 14 is a plurality of inverted U-shaped liquid-proof sheets 92 liquid-proof sheets 1 with downward flanges at both ends.
2. A liquid leakage catcher for the tank bottom plate in which the gutter 13 cooperates to continuously cover the entire lower surface of the tank bottom plate 9a has a structure. This is a drain pipe led to the receiving tank.

In such a structure, when a crack occurs in the cylindrical LNG tank l the next day, all LNG liquid leaking from the tank bottom plate 9a will be drained into the gutter by the inverted U-shaped liquid-proof sheet 9 or the heat-insulating sheet 12 with downward flanges at both ends. 13, from here it passes through the drain pipe and is collected in the leakage tank, and on the other hand,
All LNG leakage from the tank side plate 16 flows down along its outer surface, passes through the annular gutter and drain pipe 15, and is collected in the leakage tank, so that the LNG leakage does not come into contact with the hull structure such as the inner bottom plate. There is no.

According to such a structure, leakage of LNG does not come into contact with the hull structure such as the inner bottom plate, so the hull structure does not get damaged due to excessive cooling, and its safety is improved.

〔Effect of the invention〕

In short, according to the present invention, a vertical structure having a bottom plate that is supported via a heat-resistant support material that extends in the same direction on a plurality of support beams that extend in parallel to each other, and whose other portions are covered with a heat-insulating layer. In the leakage catch structure for a cylindrical liquefied gas tank, the center part of the upper end is inserted between the insulating support material and the lower surface of the bottom plate, and both ends are curved downward so as to straddle the insulating support material, and the lower end thereof a liquid-proof sheet having an inverted U-shaped cross section with an edge slightly protruding from the lower surface of the heat-insulating layer; and an inverted U-shape attached to the lower surface of the heat-insulating layer adjacent to the heat-insulating layer and having downwardly curved lower end portions adjacent to each other. a substantially horizontal liquid-proof sheet with downward flanges at both ends extending close to the lower end of each inverted U-shaped liquid-proof sheet, and a lower end of the liquid-proof sheet with downward flanges at both ends adjacent to the lower end of each of the above-mentioned inverted U-shaped liquid-proof sheets; This vertical cylindrical liquefied gas tank can be applied to tanks that have a flat bottom surface and are in contact with a plurality of support beams by being equipped with a plurality of gutters installed directly under the support beams and extending parallel to the support beams. The present invention is industrially extremely useful because it provides a leakage catch structure.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment in which the present invention is applied to an LNG ship, and FIG. 2 is a partially enlarged view showing the section (■) in FIG. 1. FIG. 3 is a longitudinal sectional view of a known spherical tank of an LNG ship. l...Next day cylindrical LNG tank, 2...Inner bottom plate, 3.
...Support girder-14...Support beam, 5...Tank support stand, 6...Insulating support material, 7...Anchor ring, 8...Heat insulation layer, 9...Inverted U-shape liquid-proof sheet, 9a...tank bottom plate, 10, 11. ll&...heatproof layer, 12...liquidproof sheet with downward flanges on both ends,
13...Gutter, 14...Leakage receiving structure, 15...Drain pipe 1.16...Tank side plate.

Claims (1)

[Claims] A leakage catcher for a vertical cylindrical liquefied gas tank that has a bottom plate that is supported on a plurality of support beams that extend in parallel to each other via heat insulating support members that extend in the same direction, and the rest of the tank is covered with a heat insulating layer. In the structure, the upper end center portion is inserted between the heat insulating support material and the lower surface of the bottom plate, and both ends are curved downward so as to straddle the heat insulating support material, and the lower edge thereof is slightly lower than the bottom surface of the heat insulation layer. A liquid-proof sheet having a protruding inverted U-shaped cross section, and both lower ends of the inverted U-shaped liquid-proof sheet attached to the lower surface of the heat-insulating layer adjacent to the heat-insulating layer and curved downward, respectively, Almost horizontal liquid-proof sheets with downward flanges at both ends extending in close proximity to each other, and the support beams laid directly below the lower ends of each inverted U-shaped liquid-proof sheet and the lower ends of the adjacent liquid-proof sheets with downward flanges at both ends. A leakage catch structure for a vertical cylindrical liquefied gas tank, characterized by comprising a plurality of gutters extending parallel to the vertical cylindrical liquefied gas tank.