JPH0335195B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a liquid storage tank suitable for storing liquid such as liquefied gas such as LNG or LPG or liquid such as petroleum, and particularly relates to an inner tank. and a liquid storage tank having an outer tank surrounding an inner tank.

(b) Technical Background Normally, in this type of liquid storage tank, if a material that does not have crack propagation stopping properties is used for the inner tank that stores liquid, if a crack occurs for some reason, the inner tank will crack in the vertical direction. The crack propagates instantly, leading to the destruction of the inner tank. Then, the liquid stored in the inner tank flows out with a violent force toward the outer tank and collides with it, causing excessive dynamic fluid pressure to act on the outer tank, potentially putting the outer tank in danger of destruction. is high.

(c) Conventional technology and problems Conventionally, as a countermeasure to this, a structure has been used in which an embankment is placed around the outer tank and the weight of the embankment is used to counteract the dynamic hydraulic pressure. is not suitable for soft ground, and concerns remain about the stability of the embankment during earthquakes.

Furthermore, in JP-A No. 57-6200, a structure is proposed in which a buffer panel is installed between the inner and outer tanks to alleviate the dynamic pressure of the flowing liquid, but the vortex acting on the buffer panels and the outer tank Since the magnitude of the dynamic hydraulic pressure caused by the flow is unknown, it is highly doubtful that a highly reliable structure can be obtained immediately.

Furthermore, Japanese Utility Model Application Publication No. 57-64491 proposes a structure in which vertical protrusions are provided on the inner surface of the outer tank to alleviate the liquid dynamic pressure. However, even with this structure, since the vertical protrusions are integrally formed with the outer tank, there remains concern about the strength of the outer tank.

Furthermore, in JP-A-57-68387, a method is proposed in which a solid body such as a tetrapod is placed between the outer tank and the inner tank, but the distance between the inner and outer tanks is usually about 1 to 2 m. Considering this, installation would be difficult and impractical.

Also, Utility Model No. 56-113300 and Utility Model Publication No. 57-
No. 20959 proposes a structure in which a buffer member or the like is installed surrounding the inner tank, but there are many problems as to how much the buffer member can withstand dynamic fluid pressure.

Moreover, all of the above examples assume that the liquid will rapidly flow out from the inner tank, and the problem is how to buffer the dynamic fluid pressure. The current situation is that it is not taken into account at all.

(d) Purpose of the Invention In view of the above-mentioned circumstances, the present invention effectively prevents the propagation and expansion of the crack when the content liquid flows out from the crack that occurs in the inner tank, and prevents the sudden flow of liquid from the inner tank. It is an object of the present invention to provide a liquid storage tank that can prevent the outer tank from being destroyed by the dynamic pressure of the liquid flowing out by preventing the liquid from flowing out.

(e1) Means for Solving the Problems That is, the present invention provides a liquid storage tank having an inner tank capable of storing a liquid therein and an outer tank surrounding the inner tank. A plurality of support means are provided along the lower part, and a plurality of deformation prevention members formed in an endless ring shape are installed on the support means in the vertical direction of the outer circumference of the inner tank so as to surround the outer circumference of the inner tank. A gap is formed between the inner tank and the outer peripheral surface of the inner tank so that the inner tank can come into contact with the deformation suppressing member only when the inner tank is deformed.

(e2) Effect With the above-described configuration, the present invention is such that the deformation suppressing member acts like a hoop when the inner tank is destroyed and the content liquid flows out, thereby preventing the rapid progress of destruction of the inner tank. It acts on

(f) Examples of the invention Examples of the present invention will be described below based on the examples shown in the drawings.

FIG. 1 is a side sectional view of the tank bottom area showing one embodiment of the liquid storage tank according to the present invention, and FIG.
FIG. 3 is a plan view of the liquid storage tank shown in FIG.
The figure shows another embodiment of the present invention, a side sectional view near the bottom of the tank, FIG. 5 is a plan view of the liquid storage tank shown in FIG. 4, and the liquid storage tank 1 is shown in FIGS. 1 and 2. As such, it has a bottom plate 3 provided on a base 2, and a cylindrical inner tank 5 with a closed upper part is installed on the bottom plate 3. A large number of support columns 6 are installed around the base 2 along the outer circumferential surface 5a of the inner tank, and each support column 6 has a plurality of brackets 6a arranged vertically in the direction of the outer circumferential surface 5a of the inner tank. It is installed protrudingly. A steel rope 7, which is a deformation suppressing member, is installed in each bracket 6a in an endless ring shape close to the lower part of the outer circumferential surface 5a of the inner tank.As shown in FIG. A plurality of them are provided in the vertical direction in FIG. 1 to surround the area. A distance L is formed between each rope 7 and the outer peripheral surface of the inner tank, and due to this distance, the rope 7 and the inner tank are completely separated physically and stress-wise. It is set up in the form. Further, a cylindrical outer tank 9 is installed around the inner tank 5 at a certain distance from the inner tank 5.

The liquid storage tank 1 has the above-mentioned configuration, so if a crack occurs at the bottom of the inner tank 5 that stores liquid such as LPG, LNG, or petroleum (normally, a crack occurs when the pressure is at its highest). In most cases, this occurs in the lower part of the inner tank, and there are many structural problems because this part also includes the joint part 5c between the bottom plate 3 and the outer peripheral surface 5a of the inner tank. The liquid inside begins to flow outside, and the crack expands further due to the pressure and other factors at that time. However, since cracks usually occur in the generatrix direction of the inner tank 5, that is, in the vertical direction in FIG. 1, as the cracks occur and expand, the outer diameter D of the inner tank 5 increases. However, since the steel rope 7 is installed on the outer circumferential surface 5a of the inner tank 5, the inner tank 5 becomes hoop-fitted by the rope 7, and the outer diameter D increases beyond a certain level. Therefore, the expansion of cracks is prevented, the amount of liquid flowing out from the inner tank 5 is small, and complete destruction of the inner tank 5 and rapid outflow of the internal liquid are prevented.

In addition, in a normal state, the rope 7 is physically separated from the inner tank 5 by a distance L, so the rope 7 does not exert any restraint on the inner tank 5. (In other words, no tensile stress is acting on the rope 7 under normal conditions.) In the event of an emergency spill, deformation of the inner tank 5 is prevented to the maximum extent until the rope 7 yields. It can exhibit extremely strong deformation prevention effects.

Further, in the above-described embodiment, a case was described in which the support member, that is, the support column 6, that supports the steel rope 7, which is the deformation suppressing member of the inner tank 5, was provided separately from the inner tank 5. As shown in the figure, the inner tank outer peripheral surface 5a
A plurality of brackets 5d may be installed on the brackets 5d, and the rope 7 may be supported on the brackets 5d.

Further, the deformation suppressing member is not limited to the rope 7, and may be of any type as long as it can prevent the expansion deformation of the outer diameter D due to cracks in the inner tank 5. For example, as shown in FIGS. 4 and 5, As shown, an endless annular steel band 10 may be connected to the support column 6 by welding or the like. However, in any case, the distance L between each deformation suppressing member and the inner tank outer circumferential surface 5a needs to be provided close enough to prevent the outer diameter D from expanding due to cracks in the inner tank 5. Of course.

(g) Effects of the Invention As explained above, according to the present invention, the liquid storage tank 1 has an inner tank 5 capable of storing a liquid therein, and an outer tank 9 surrounding the inner tank. A plurality of support means such as a support column 6 and a bracket 5d are provided along the lower part of the outer peripheral surface 5a of the inner tank, and deformation prevention members such as a rope 7 and a band 10 formed in an endless ring shape are attached to the support means. A plurality of members are installed in the vertical direction of the outer peripheral surface of the inner tank so as to surround the outer periphery of the inner tank, and between the deformation suppressing member and the outer peripheral surface of the inner tank, the inner tank is installed only when the inner tank is deformed. Since the structure is configured by forming a distance L that can contact the deformation suppressing member, even if a crack occurs in the inner tank 5 and the content liquid flows out, and the crack attempts to expand, the deformation suppressing member will prevent it. and its expansion was prevented,
It is possible to effectively suppress the propagation of cracks, and to prevent the risk of rapid outflow of the liquid in the inner tank 5 and the accompanying destruction of the outer tank 9. Therefore, in preparation for a sudden outflow of liquid, the outer tank 9
The strength of the outer tank 9 can be strengthened by embanking the outside of the tank.
A liquid storage tank that is safer and causes less damage in the event of an emergency than post-treatment measures such as installing buffer panels, vertical ridges, solid bodies, buffer members, etc. on the inner surface of the outer tank or between the inner and outer tanks. 1 can be provided.

Furthermore, since a gap is formed between the deformation suppressing member and the outer peripheral surface of the inner tank so that the inner tank can come into contact with the deformation suppressing member only when the inner tank is deformed, it is possible to prevent the inner tank from being destroyed. In this state, there is no physical contact between the deformation suppressing member and the inner tank, and it is possible to prevent tensile stress from acting on the deformation suppressing member from the inner tank side. Therefore, when the tank is destroyed, the deformation prevention member can be used to suppress the deformation of the inner tank to its full physical strength, and after the tank is destroyed, it is possible to exert a strong deformation prevention effect, increasing reliability. This makes it possible to provide a liquid storage tank with high performance.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the tank bottom area showing an embodiment of the liquid storage tank according to the present invention, and FIG.
FIG. 3 is a plan view of the liquid storage tank shown in FIG.
The figure shows another embodiment of the present invention, a side sectional view near the bottom of the tank, FIG. 5 is a plan view of the liquid storage tank of FIG. 4, and FIG. 6 shows still another embodiment of the present invention. 7 is a plan view of the liquid storage tank of FIG. 6, and FIG. 8 is a side sectional view of the vicinity of the tank bottom, showing still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Liquid storage tank, 5...Inner tank, 7...Deformation suppressing member (rope), 9...Outer tank, 9a...Deformation suppressing member (lower inner surface of outer tank), 10...Deformation suppressing member (band ), 11... Deformation suppressing member (wall), D...
Outer diameter.

Claims (1)

[Scope of Claims] 1. A liquid storage tank having an inner tank capable of storing a liquid therein, and an outer tank surrounding the inner tank, including: a support means is provided, a plurality of deformation prevention members formed in an endless ring shape are installed on the support means in a vertical direction of the outer circumference of the inner tank so as to surround the outer circumference of the inner tank, and the deformation prevention member and the Between the outer circumferential surface of the inner tank,
A liquid storage tank configured to form a gap between which the inner tank can come into contact with the deformation suppressing member only when the inner tank is deformed. 2. The liquid storage tank according to claim 1, wherein the deformation suppressing member is a rope. 3. The liquid storage tank according to claim 1, wherein the deformation suppressing member is a band.