JP2003240196A - Low temperature double shell tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low temperature double shell tank preventing stress formed in anchors at the time of leakage of low temperature liquefied gas. <P>SOLUTION: This low-temperature double shell tank 18 is provided with a secondary bottom laid between a tank inner bath 3 and a tank outer bath 4 and capable of receiving the low temperature liquefied gas 2 leaked from the tank inner bath 3, and the anchors 12 stretched penetrating through the secondary bottom 19 to fix the tank inner bath 3. The secondary bottom 19 forms a corrugation 20 absorbing thermal contraction caused by the leakage of the low temperature liquefied gas 2. This constitution prevents the stress formed in the anchors 12 and improves the durability of the secondary bottom 19, the anchors 12, and the tank inner bath 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature double shell tank having a secondary bottom.

[0002]

2. Description of the Related Art As an example of a low temperature double shell tank for storing a low temperature liquefied gas such as LNG, as shown in FIG. 4, a low temperature double shell tank 1 is a tank inner tank 3 for storing a low temperature liquefied gas 2. And a tank outer tank 4 that surrounds the tank inner tank 3 to form a PC (prestressed concrete) dike, and between the tank inner tank 3 and the tank outer tank 4 is a tank inner tank bottom plate 5. A secondary bottom 9 is laid from the bottom 7 of the outer tank of the tank via a cold insulating material 6 such as foam glass or perlite concrete, and a secondary barrier cold insulating material 8 such as foam glass or perlite concrete.

The secondary bottom 9 is formed in a shape surrounding the lower part of the tank inner tank bottom plate 5 and the lower part of the tank inner tank side plate 10 by a lining steel plate of 9% steel so as to receive the low temperature liquefied gas 2 leaked from the tank inner tank 3. ing. In the figure, reference numeral 11 denotes a cold insulating material such as granular pearlite filled between the tank inner tank 3 and the tank outer tank 4.

On the other hand, such a low temperature double shell tank 1 is
When installing in an area where a large earthquake occurs, an anchor is used as shown in Fig. 5 to prevent the tank tub 3 from slipping or rising and damaging due to the shaking of the earthquake. It is considered to connect the tank 4 and fix the tank 3 in the tank.

As an anchor, it is generally a tank tank 3
Anchor straps 12 are stretched at predetermined intervals in the circumferential direction to connect the tank inner tank 3 and the tank outer tank 4, and the tank inner tank 3 and the anchor straps 12 are lower than the outer peripheral surface of the tank inner tank side plate 10. The protrusions 15 of the anchor straps 12 are connected to the insertion portions 14 attached to the tank outer tank 4 and the anchor straps 12 by connecting them.
Is an anchor box 1 embedded in the bottom 7 of the outer tank
It is connected by fixing the lower end of the anchor strap 12 to 6.

For this reason, the anchor strap 12 is structurally penetrated through the secondary bottom 9 and stretched around the bottom portion 7 of the tank outer tank, and the secondary bottom 9 is leaked at a low temperature due to the through hole 17 for the anchor strap 12. It is necessary to weld the secondary bottom 9 and the anchor strap 12 to close the through hole 17 so as to prevent the performance of receiving the liquefied gas 2 from being deteriorated.

[0007]

However, when the low-temperature liquefied gas 2 leaks from the tank inner tank 3 to the secondary bottom 9, the secondary bottom 9 undergoes thermal contraction, so that the secondary bottom 9 is located in the through hole 17 of the secondary bottom 9. There is a risk that stress may be generated in the anchor strap 12 and displacement may occur, which may damage the liquid tightness of the secondary bottom 9 itself,
It is considered that the anchor strap 12 and the tank 3 in the tank may be damaged.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a low temperature double shell tank which prevents the stress of the anchor from being generated when the low temperature liquefied gas leaks.

[0009]

A low temperature double shell tank according to the present invention comprises a secondary bottom which is laid between a tank inner tank and a tank outer tank and can receive low temperature liquefied gas leaked from the tank inner tank, and the tank. A low temperature double shell tank having an anchor stretched through the secondary bottom so as to fix the inner tank, wherein the secondary bottom is
The corrugation is formed to absorb the heat shrinkage due to the leakage of the low temperature liquefied gas.

In the low temperature double shell tank of the present invention,
The corrugation may be formed between the tank inner tank and the anchor so as to surround the outer circumference of the tank inner tank.

Further, in the low temperature double shell tank of the present invention, a plurality of corrugations are formed between the tank inner tank and the anchor and between the anchor and the tank outer tank so as to surround the outer circumference of the tank inner tank. Good.

As described above, when the low temperature liquefied gas leaks from the tank inner tank to the secondary bottom, the corrugation absorbs the thermal contraction of the secondary bottom, so that the stress of the anchor is prevented from occurring and the secondary bottom, the anchor and the tank are prevented. It is possible to prevent damage to the inner tank and improve durability.

Further, when the corrugation is formed between the tank inner tank and the anchor so as to surround the outer circumference of the tank inner tank, the corrugation partitions the secondary bottom into a heat shrinkable portion and a heat non-shrinkable portion. Therefore, it is possible to easily dispose the anchor on a portion of the secondary bottom where heat does not shrink, and to reliably prevent the stress of the anchor from occurring.

Further, when a plurality of corrugations are formed between the tank inner tank and the anchor and between the anchor and the tank outer tank so as to surround the outer circumference of the tank inner tank, the corrugation heat-shrinks the secondary bottom. Since it is partitioned into a part that does not heat shrink and a part that does not heat shrink, the anchor can be easily and appropriately arranged on the part of the secondary bottom that does not heat shrink,
It is possible to more reliably prevent the stress of the anchor from occurring.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a first example for carrying out the embodiment of the present invention. In the drawings, the parts designated by the same reference numerals as those in FIGS. 4 and 5 represent the same parts.

The low-temperature double-shell tank 18 comprises a bottom plate 5 in the tank between the inner tank 3 and the outer tank 4 and a cooling material 6 such as foam glass or pearlite concrete, and a bottom 7 in the outer tank. A secondary bottom 19 is laid via a secondary barrier cold insulating material 8 such as glass or perlite concrete. The secondary bottom 19 is a tank made of a stainless steel membrane so as to receive the low temperature liquefied gas 2 leaked from the tank inner tank 3. The inner tank bottom plate 5 and the tank inner tank side plate 10 are configured so as to surround lower portions thereof.

In the low temperature double shell tank 18, anchor straps 12 are arranged at predetermined intervals in the circumferential direction of the tank inner tank 3 so that the tank inner tank 3 does not move and be damaged by the shaking of the earthquake. The tank 3 is fixed, and the secondary bottom 1
An anchor strap 12 penetrating 9 connects the tank inner tank 3 and the tank outer tank 4. Here, the through hole 17 for the anchor strap 12 formed in the secondary bottom 19 is closed by welding the secondary bottom 19 and the anchor strap 12 so as to maintain the performance of receiving the low temperature liquefied gas 2 of the secondary bottom 19. ing.

On the other hand, an annular corrugation 20 is formed between the inner tank 3 of the secondary bottom 19 and the anchor strap 12 so as to surround the outer circumference of the inner tank 3, and the secondary bottom 19 is fixed to the bottom plate 5 of the inner tank.
The central portion 21 located below the anchor and the anchor strap 1
The corrugation 20 is divided into an outer peripheral portion 22 through which the 2 is fixed, and the corrugation 20 is formed in a pleated shape by curving the secondary bottom 19 upward. Here, the inside of the corrugation 20 is hollow without being filled with the secondary barrier cold insulating material 8. The corrugation 20 may have a circular shape, an elliptical shape, or a polygonal shape.

The operation of the first example of the embodiment of the present invention will be described below.

When the low temperature liquefied gas 2 leaks from the tank inner tank 3, the central portion 21 of the secondary bottom 19 is thermally contracted, and at this time, the corrugation 20 absorbs the contraction amount of the central portion 21 and the secondary bottom. The outer peripheral portion 22 of 19 is deformed so as not to be affected by contraction to prevent interference with the anchor strap 12. When the secondary bottom 19 receives the leaking low temperature liquefied gas 2, the liquid load of the low temperature liquefied gas 2 is supported by the lower secondary barrier cold insulator 8.

In this way, when the low temperature liquefied gas 2 leaks from the tank inner tank 3 to the central portion 21 of the secondary bottom 19, the corrugation 20 becomes the secondary bottom 19.
Since it absorbs the heat shrinkage of the central portion 21 and is deformed, the generation of stress that gives a displacement to the anchor strap 12 is prevented, and the anchor strap 12, the tank inner tub 3, the secondary bottom 19 are prevented from being damaged, etc. The safety can be improved.

Also, the corrugation 20 is a tank inner tank 3
Located between the anchor strap 12 and the tank strap 3
When formed so as to surround the outer periphery of the corrugation 20
However, the secondary bottom 19 is heat-shrinked at the central portion 21.
The anchor strap 12 can be easily arranged on the outer peripheral portion 22 that does not undergo heat shrinkage, and the occurrence of stress on the anchor strap 12 can be reliably prevented.

FIG. 3 shows a second example for carrying out the embodiment of the present invention, in which the corrugation is changed.
The parts denoted by the same reference numerals as those in FIGS. 1 and 2 represent the same parts.

The tank inner tank 3 and the anchor strap 12 in the secondary bottom 24 of the low temperature double shell tank 23
Between the anchor strap 12 and the tank outer tub 4, two annular corrugations 25 are formed so as to surround the outer circumference of the tank inner tub 3, and the secondary bottom 24 is
It is divided into a central portion 26 located below the tank inner tank bottom plate 5, an inner peripheral portion 27 through which the anchor strap 12 is fixed through, and an outer peripheral portion 28 located at the outermost side, and the two corrugations 25 are By curving the secondary bottom 24 upward, the secondary bottom 24 is formed in a pleated shape. Here, the inside of the corrugation 25 is hollow without being filled with the secondary barrier cold insulating material 8. The corrugation 25 may have a circular shape, an elliptical shape, or a polygonal shape.

The operation of the second example of the embodiment of the present invention will be described below.

When the low temperature liquefied gas 2 leaks from the tank inner tank 3, the central portion 26 of the secondary bottom 24 is thermally contracted and the outermost outer peripheral portion 28 under various conditions.
Heat-shrinks, and at this time, the two corrugations 25 absorb the shrinkage amount of the central portion 26 and the outer peripheral portion 28 and are deformed so as not to affect the inner peripheral portion 27 of the secondary bottom 24. The interference with 12 is prevented. When the secondary bottom 24 receives the leaking low temperature liquefied gas 2, the liquid load of the low temperature liquefied gas 2 is supported by the lower secondary barrier cold insulator 8.

As described above, when the low temperature liquefied gas 2 leaks from the tank inner tank 3 to the secondary bottom 24 and the central portion 26 and the outer peripheral portion 28 of the secondary bottom 24 are thermally contracted, the two corrugations 25 are secondary. Since the central portion 26 and the outer peripheral portion 28 of the bottom 24 are deformed by absorbing the thermal contraction, the generation of stress giving displacement to the anchor strap 12 is prevented, and the secondary bottom 24, the anchor strap 12, the tank inner tank 3, and the anchor connection portion. It is possible to prevent damage and the like to improve durability and safety.

The corrugation 25 is used for the tank 3 in the tank.
A plurality of corrugations 25 are formed between the anchor strap 12 and the anchor strap 12 and between the anchor strap 12 and the tank outer tank 4 so as to surround the outer circumference of the tank inner tank 3.
However, the secondary bottom 24 is partitioned into a central portion 26 and an outer peripheral portion 28 that are heat-shrinkable, and an inner peripheral portion 27 that is not heat-shrinkable.
4 can be easily and properly arranged on the inner peripheral portion 27 which does not heat-shrink,
Generation of stress on the anchor strap 12 can be prevented more reliably.

The low-temperature double-shell tank of the present invention is not limited to the above-mentioned embodiment, and what is necessary is that the corrugation absorbs the thermal contraction of the secondary bottom without generating stress in the anchor. Needless to say, various shapes, arrangements, and numbers may be used, and various changes may be made without departing from the scope of the present invention.

[0031]

According to the low temperature double shell tank of the present invention, various excellent effects as described below can be obtained.

I) When low-temperature liquefied gas leaks from the tank inner tank to the secondary bottom, the corrugation absorbs the heat shrinkage of the secondary bottom, so that the anchor stress is prevented from occurring and the secondary bottom, anchor and tank inner tank are prevented. It is possible to prevent damage to the product and improve durability.

II) When the corrugation is formed between the tank in the tank and the anchor so as to surround the outer circumference of the tank in the tank, the corrugation partitions the secondary bottom into a heat shrinkable portion and a heat non-shrinkable portion. Therefore, it is possible to easily dispose the anchor on a portion of the secondary bottom where heat does not shrink, and to reliably prevent the stress of the anchor from occurring.

III) When a plurality of corrugations are formed between the tank inner tank and the anchor and between the anchor and the tank outer tank so as to surround the outer circumference of the tank inner tank, the corrugation thermally contracts the secondary bottom. Since the partition is divided into a portion that does not heat-shrink and a portion that does not heat-shrink, the anchor can be easily and properly arranged in the portion of the secondary bottom that does not heat-shrink, and the stress of the anchor can be more reliably prevented from occurring.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the entire structure in a first example of the form of a low temperature double shell tank of the present invention.

FIG. 2 is an enlarged view showing an anchor strap and a corrugation in the first example of the form of the low temperature double shell tank of the present invention.

FIG. 3 is an enlarged view showing an anchor strap and a corrugation in a second example of the form of the low temperature double shell tank of the present invention.

FIG. 4 is a vertical cross-sectional view showing the entire structure of a conventional low temperature double shell tank.

FIG. 5 is an enlarged view showing an anchor strap in a conventional low temperature double shell tank.

[Explanation of symbols]

2 Low temperature liquefied gas 3 tank inner tank 4 tank outer tank 9 Secondary bottom 12 Anchor strap (anchor) 18 Low temperature double shell tank 19 Secondary Bottom 20 Corrugation 23 Low temperature double shell tank 24 Secondary Bottom 25 Corrugation

Continued front page    (72) Inventor Masahiko Ikeuchi             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Tokyo Engineering Co., Ltd.             In the center (72) Inventor Hidenori Suzuki             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Tokyo Engineering Co., Ltd.             In the center (72) Inventor Seiji Horiguchi             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Tokyo Engineering Co., Ltd.             In the center (72) Inventor Tetsuo Kaneshiro             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Tokyo Engineering Co., Ltd.             In the center F-term (reference) 3E073 BA21 BA44 BB01

Claims (3)

[Claims] 1. A secondary bottom that is laid between the tank inner tank and the tank outer tank and that can receive low-temperature liquefied gas leaked from the tank inner tank, and a tension extending through the secondary bottom so as to fix the tank inner tank. A low temperature double shell tank provided with an anchor, wherein the secondary bottom forms a corrugation that absorbs thermal contraction due to leakage of low temperature liquefied gas. 2. The low temperature double shell tank according to claim 1, wherein the corrugation is formed between the tank inner tank and the anchor so as to surround the outer periphery of the tank inner tank. 3. A plurality of corrugations are formed between the tank inner tank and the anchor and between the anchor and the tank outer tank so as to surround the outer circumference of the tank inner tank.
Low temperature double shell tank as described.