JPS5817198Y2 - Tank suspended ceiling structure - Google Patents

Description

[Detailed explanation of the invention] This invention relates to the suspended ceiling structure of tanks, especially for LNG and LNG.
The present invention relates to a suspended ceiling structure for a tank containing low-temperature liquefied gas such as PG, in which the suspended ceiling suspended between the roof and the liquid storage surface in the tank is endowed with earthquake resistance.

It is generally known that during an earthquake, liquid stored in a tank causes a sloshing phenomenon.

This sloshing phenomenon occurs when the free surface of the liquid in the tank resonates, resulting in large amplitude and large oscillating waves.

In particular, above-ground tanks for storing low-temperature liquefied gas,
Underground or semi-underground tanks are generally used, and these tanks have become increasingly larger in recent years, with diameters of up to 60 m.
Even more than that have appeared.

These tanks have suspended ceilings to keep the stored liquid cool.

This suspended ceiling is suspended from the roof of the tank so as to cover the liquid storage surface, and a cold insulation material is placed on the top surface of the suspended ceiling.

However, when the distance between the suspended ceiling for cold storage and the liquid level is short, there is a possibility that the liquid will collide with the suspended ceiling if the liquid shakes during an earthquake.

This point will be specifically explained with reference to FIG. 1, which shows a conventional tank.

A conventional tank 1 of this type has a cylindrical concrete tank body 2 buried underground G, and a dome-shaped roof 3 formed at the upper opening of the tank body 2.

A suspended ceiling 4 is provided inside the roof 3 so as to cover the liquid storage surface.

A cold insulating material 5 is placed on this suspended ceiling 4, and a cold insulating material layer is formed on the liquid storage surface.

By the way, when a sloshing phenomenon occurs in the reservoir during an earthquake, the oscillating wave A increases in amplitude as shown in the figure, and the peripheral portion of the tank alternately moves up and down with the central portion of the tank as an axis.

As the rocking plate A vibrates in this way, the peripheral edge of the liquid reservoir rises, colliding with the suspended ceiling 4 and causing the suspended ceiling 4 to collide with the suspended ceiling 4.
is pushed up toward the side of the roof 3, and at the same time, the rod 6 supporting the suspended ceiling 4 is bent.

If an even larger swing wave is generated and collides with the suspended ceiling 4, the rod 6 will buckle and the suspended ceiling 4 will be further pushed up, which may cause it to collide with the roof 3 and destroy it.

If the roof 3 is destroyed in this way, there is a possibility that the stored liquid will leak out of the tank 1.

Therefore, the present invention was devised in view of the problems of the suspended ceiling structure of conventional tanks and to effectively solve these problems.

The purpose of this invention is to sufficiently withstand the impact force of the oscillating waves caused by the sloshing phenomenon of stored liquid that occurs during earthquakes, and to withstand thermal shock caused by contact with low-temperature stored liquid. To provide a suspended ceiling structure for a tank capable of preventing damage from occurring.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is an enlarged sectional view of the main parts showing one embodiment of the present invention;
The figure is a view taken along the line A--A in FIG. 2, and FIG. 4 is a partially sectional perspective view of the truss structure used in the present invention.

As shown in FIGS. 2 and 3, the suspended ceiling 10 mainly includes a ceiling plate 11 made of light aluminum alloy, a rod member 12 for suspending the ceiling plate 11, a truss structure 13, and a buffer member 14 having cold insulation properties. It consists of

The ceiling plate 11 made of aluminum light alloy forms the suspended ceiling 10, and the rod member 12 is connected from the roof beam 15.
suspended horizontally.

A joint 16 is provided on the ceiling plate 11, and a rod member 12 whose one end is supported by the roof beam 15 is attached to the joint 16.
are set up consecutively.

In particular, the rod member 12 is set to have a minimum cross-sectional area that is strong enough to support the ceiling plate 11 and the cold insulating material 17 placed on the ceiling plate 11.

Therefore, the structure is such that the thermal conductivity from the ceiling plate 11 to the roof beam 15 and the like is made as small as possible.

By suspending the ceiling plate 11 below the inside of the roof 18 in this manner, the suspended ceiling 10 is supported horizontally on the liquid storage surface of the tank 20.

In particular, in the present invention, on the peripheral portion 19 of the suspended ceiling 10,
A feature is that a truss structure 13 is formed between the suspended ceiling 10 and the roof 18.

This truss structure 13 is formed in an annular shape on the peripheral edge 19 of the suspended ceiling.

Further, the truss structure 13 is as shown in FIGS. 2 to 4.
It is constructed by joining beam members 21, 22 made of steel plates, and each beam member 21, 224. They are movably connected.

First, as shown in FIGS. 2 and 3, the roof beam 15 is provided with joint plates 23, and the vertical beam members 21 are attached to these joint plates 23.

Horizontal beam members 22, which are appropriately spaced apart from each other on the surface of the suspended ceiling 10, are connected to the lower ends 21a of these vertical beam members 21 via joint plates 23.

The horizontal beam member 22 serves to restrict upward movement of the peripheral edge 19 of the suspended ceiling.

As shown in FIG. 4, a long hole 24 having a predetermined length is formed in the joint plate 23 that connects the vertical beam member 21 and the horizontal beam member 22 along the longitudinal direction of each beam member 21.22. A pin 25 is inserted and locked into this elongated hole 24 and connected to the beam member 21.22.

Therefore, each beam member 21, 22 is connected to the joint plate 23.
The beam member is movably connected to the beam member by a pin, and is configured to be allowed to move in the longitudinal direction of the beam member along the elongated hole 24 of the joint plate 23.

. In this way, the truss structure 13 is formed along the peripheral edge 19 of the suspended ceiling, and the horizontal beam member 22 constituting the bottom of the truss structure 13 is fixed as shown in FIGS. 2 and 3. "
.

A buffer member 14 having cold insulation properties is interposed within this gap 26.

The buffer member 14 is made of a material such as urethane foam that has sufficient cold insulation and compressive strength, and is particularly formed to cover the horizontal beam member 22 as shown.

- Also, in the illustrated embodiment, the peripheral edge 19 of the suspended ceiling 10
is formed to be inclined downward, and an annular wall 27 is formed on the outer peripheral edge 19a of the annular wall 27, which hangs down close to the inner wall 2a of the tank body 2.

On the other hand, a membrane 3 stretched on the inner wall 2a of the tank body 2.
0 extends above the upper edge 28 of the tank body and is welded onto a side wall plate 29 supporting the roof 18.

Further, a cold insulating material 31 such as urethane foam is laminated on the upper edge portion 28, and a membrane 30 is stretched over this cold insulating material 31.

Furthermore, a cold insulating material layer 32 is formed on the membrane 30 and extends over the inner wall 18a of the roof 18.

A bag 33 formed in an annular shape is interposed between the annular wall 27 and the upper edge 28 of the tank body, and inside this bag 33 is a cold insulator made of elastic material such as glass wool. The material 34 is filled.

Therefore, this bag body 33 seals between the tank body 2 and the suspended ceiling 10, thereby increasing the insulation effect between the atmosphere inside the tank body 2 and the atmosphere between the suspended ceiling 10 and the roof 18.

Furthermore, a cold insulating material 35 such as glass wool is filled between the roof 18 on the bag body 33 and the suspended ceiling 10.

Note that a cold insulation layer 36 such as urethane foam is laminated on the roof beam 15 supporting the truss structure 13 and the joint plate 23 connected thereto.

A cold insulation material 1 such as glass wool is placed above the center of the suspended ceiling 10.
7 is placed to form the cold insulation layer 5a.

The operation of the present invention constructed as above will be described.

First, a sloshing phenomenon occurs, and the oscillating waves reach suspended ceiling 1.
Even if it collides with the peripheral edge 19 of the suspended ceiling 1, this shock wave pressure
The suspended ceiling 10 is buffered and attenuated by the truss structure 13 interposed above the suspended ceiling 10, thereby preventing the suspended ceiling 10 from being destroyed.

In particular, in the illustrated example, since the peripheral edge 19 of the suspended ceiling 10 is inclined, the reflected waves are returned to the inside of the tank, and the next oscillating wave is further canceled by the cancellation of this reflected wave. Impact pressure will be reduced.

Next, even if the truss structure 13 undergoes thermal contraction due to the low-temperature storage liquid coming into contact with the suspended ceiling 10 due to the oscillating waves, the beam members 21 and 22 constituting the truss structure 13 will not move in their longitudinal direction. Since movement is allowed, it can be tolerated sufficiently.

- each beam member 21 as shown in FIG.
．． Since the beam member 22 moves along the elongated hole 24 of the joint plate 23, breakage of the material due to thermal contraction of the beam member can be prevented.

Therefore, there is no need to form these truss structures 13 from low-temperature materials.

In summary, the present invention exhibits the following excellent effects.

(1) It can sufficiently withstand the shaking waves caused by the sloshing phenomenon during an earthquake, and the safety of this type of low-temperature tank can be improved as much as possible.

(2) Even if the low-temperature stored liquid comes into direct contact with the suspended ceiling due to the oscillation waves, the supporting members that support it can be prevented from being destroyed by heat shrinkage. It can be provided at low cost without requiring the use of

(3) The structure is simple and can be easily applied to conventional or existing tanks.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing a suspended ceiling structure of a conventional tank, Fig. 2 is an enlarged sectional view of a main part showing a preferred embodiment of the present invention, Fig. 3 is a view taken along arrow A-A in Fig. 2, FIG. 4 is a partially sectional perspective view of the truss structure used in the present invention. In the figure, 18 is the roof of the tank, L is the liquid storage surface, 10 is the suspended ceiling, 19 is the periphery, 13 is the truss structure, and 14 is the buffer section.

Claims (1)

[Scope of utility model registration request] In a suspended ceiling supported between the roof of the tank and the liquid storage surface so as to cover the liquid storage surface, a heat-shrinkable truss structure is interposed between the peripheral edge of the suspended ceiling and the roof. A suspended ceiling structure for a tank, characterized in that a buffer member having cold insulation properties is provided between the truss structure and the suspended ceiling.