JPS61167799A - Liquid tight heat insulating structure for emergency use of low temperature liquid tank - Google Patents

Abstract

PURPOSE:To improve liquid-tightness and heat insulating performance by installing double layer heat insulating panel, which consists of a pair of upper and lower square plates placed with mutual shifts in longitudinal and lateral directions, on the inner surface of the outer shell of the tank with the inner and outer joints filled with an elastic filler and a double holding material. CONSTITUTION:A double layer heat insulating panel A is made of the upper square plate 11 and lower square plate 12 overlapping each other with mutual shifts in both longitudinal and lateral directions. The panel A is installed on the inner surface of the outer shell B of a low temperature tank, with its outer joint (a) and inner joint (b) filled with an elastic bubble holding material 13 and an elastic joint filler 14. Thus relative displacement of the plates of the panel A to some extent does not cause loakage of heat or the liquid in the tank to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an emergency liquid-tight insulation structure for a low temperature liquid storage tank such as an LPG, LNG storage tank, etc.

(Prior Art) The outer shell (1) of a low-temperature liquid storage tank is mainly made of ordinary steel, concrete, or the like. The inner surface of the outer shell (1) is provided with a heat insulating material (2) for cold preservation and an inner shell or membrane (3) for maintaining liquid tightness in a layered manner.

In the case of a land tank, the liquid level (5) of the low-temperature liquid (4) in the tank
Since it is in a stationary state, normally there is no need for a liquid-tight layer above the liquid level (5), but considering the fluctuation of the liquid level due to an earthquake,
A liquid-tight layer is provided up to the highest possible liquid dynamic level (6). (7) in the figure is the mineral vaporization gas layer (see Figure 5)
.

(Problems to be Solved by the Invention) However, since the time for the liquid level to oscillate is at most 30 minutes, a simple liquid-tight structure that can withstand this period on a still liquid level is sufficient.

For this reason, it is conceivable to support the inner circumferential surface of the outer shell of the storage tank above the still liquid surface with bolts or the like, with a nonel-shaped insulating material that can maintain liquid tightness, such as closed-cell polyurethane foam. A joint is provided in between to allow it to contract due to cold heat, but at extremely low temperatures, the rubber
Joint materials that are stretchable at room temperature, such as polyurethane foam, not only become brittle and lose their elasticity, but also easily break under tensile force, so we found a joint material that can absorb this shrinkage at extremely low temperatures. That is difficult.

(Means for Solving the Problems) The present invention has been proposed to solve these problems, and the present invention has been proposed in such a way that a pair of upper and lower rectangular plates are arranged mwt apart from each other in both vertical and horizontal directions. integrally layered heat insulating panels are assembled and stacked on the inner circumferential surface of the outer shell of the storage tank above the static liquid level in the storage tank, and an outer joint is formed between the adjacent heat insulating panels and communicates with the inner circumferential surface of the outer shell; and forming an inner joint whose one end communicates with the outer joint and whose other end opens into the storage tank, and the outer joint and the inner joint are loaded with an elastic filler and a bubble retaining material, respectively. This relates to an emergency liquid-tight insulation structure for a cryogenic liquid storage tank.

(Function) In the present invention, as described above, a pair of upper and lower rectangular plates are integrally layered so as to overlap each other in both the vertical and horizontal directions to form a heat insulating material panel, and the panel is used to store static liquid in a storage tank. The walls of the tank outer shell at the top of the panel are laminated and layered to form outer joints between the lower square panels of the flannel, as well as between the upper square panels of the adjacent panels and both upper and lower engravings. An inner joint that communicates with the outer joint is formed between the overlapping parts, a stretchable joint filler is loaded on the outer joint in contact with the outer shell of the storage tank, and a stretchable air bubble retaining material is mounted on the inner joint. Therefore, even if heat shrinks, the adjacent cold insulation panels will only slide at the part where they sandwich the inner joint and overlap, so the stretchable air retaining material stacked on the inner joint will The insulating properties of the bubbles in the vaporized gas and the pressure of the vaporized gas prevent the low-temperature liquid in the tank from entering the joints without loss of functionality.

On the other hand, the elastic joint filler loaded at the outer joints of the adjacent insulation panels is in contact with the outer shell on the normal temperature side,
In addition, it is protected by the insulation of vaporized gas within the inner joint,
Since it maintains a certain temperature, it does not lose its elasticity. Therefore, it is possible to prevent vaporized gas from escaping and to prevent the low-temperature liquid in the tank from flowing into the joints.

(Effects of the Invention) According to the present invention, as described above, the low temperature liquid stored in the storage tank and whose liquid temperature is normally at the boiling point is layered on the inner peripheral surface of the outer shell at the upper part of the static liquid level in the storage tank. At the same time, the air bubbles generated by vaporization when entering the insulating material remain in the joints formed between the insulation panels for as long as possible to maintain the insulation effect. It is possible to prevent the intrusion of water for a certain period of time and achieve the liquid-tight function of the heat insulating material alone, thereby reducing costs.

Furthermore, according to the present invention, as described above, the insulation layer on the inner circumferential surface of the storage tank outer shell is constructed by laminating the insulation panels, so spraying is more effective than the conventional insulation construction method using foaming. Easy on-site construction. In addition, the foam spraying method requires careful reinforcement with reinforcing fibers to prevent the insulation material from cracking due to cold heat, but according to the present invention, factory-produced insulation panels can be used as is. A highly reliable insulation layer can be easily constructed.

(Example) The present invention will be described below with reference to the illustrated embodiments.

(N is a liquid-tight insulation made of polyurethane foam with closed cells, etc., which is formed by layering the upper rectangular plate (11) and the lower rectangular plate (12) in both the vertical and horizontal directions. The panels (A) are stacked and stacked vertically and horizontally on the inner peripheral surface of the outer shell above the liquid surface of the cold storage liquid in the low temperature storage tank, and adjacent insulation panels (8 ) between the lower square plates (12) of the outer shell (to), and between each upper square plate (11) (11) of the adjacent insulation material nosonels (A)K, and the outer joint (α) I between the upper rectangular plate (11) of one panel and the lower rectangular plate (12) of the other panel.
An inner joint (b) that communicates with C is formed, and the insulation material/gunnel (A) is constructed so that it can be contracted by the inner and outer joints (α) (ARK).

The inner joint (α) is filled with a corrugated material made of thin plates such as aluminum, or an elastic bubble retaining material (13) made of glass wool, etc.
The outer joint (α) in contact with is filled with a stretchable joint filler (14) such as polyurethane/foam.

Note that the /ξ channel (A) has an outer shell (B) so that it can slide.
It is supported by the pole (15), the oak (I6), and the washer (17), and the heat input to the pole (15) is prevented by the insulation cap (18).

(See FIG. 2) Since the illustrated embodiment is constructed as described above, the adjacent insulation panels (A) can also be heated to shrink the overlapping surfaces of the upper and lower engravings (11) and (12). Just by sliding, the panel (A) is displaced relative to the adjacent panel to the position shown by the dotted line in FIGS. 1 and 2, and the elastic bubble retaining material (13) does not lose its function. The cryogenic liquid (q Prevents intrusion into the joint.

On the other hand, the elastic joint filler (14) filled in the outer joint (α) is in contact with the outer shell (to) on the normal temperature side, and due to the heat insulation properties of the vaporized gas in the inner joint (h). Since the temperature is maintained at a certain level, elasticity is not lost, and this prevents vaporized gas from escaping and prevents the low-temperature liquid (C) from entering the joint.

According to the illustrated embodiment, the insulation panel alone performs the liquid-tight function for a certain period of time, so there is no need to provide a liquid-tight structure above the liquid level in the low-temperature liquid storage tank. It is possible to significantly reduce costs, and it is also possible to use insulation panels (AI) that are pre-fabricated in factories etc.
15), the outer shell (E)K is attached to form the heat insulating layer, so a highly reliable liquid-tight heat insulating layer for emergencies can be easily constructed.

Note that the present invention is also applied to the inner surface of a steel dome of an underground LNG tank.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and the design of the present invention may be modified without departing from the spirit of the present invention. be.

[Brief explanation of the drawing]

1 and 2 are cross-sectional plan views showing an embodiment of the emergency liquid-tight insulation structure for a low-temperature liquid storage tank according to the present invention. Figures -■ and 3 are partial front views thereof, Figure 4 is a perspective view of a heat insulating panel, and Figure 5 is a vertical sectional view of a conventional cryogenic liquid storage tank. (A)...Insulation panel, (B)...Outer shell, (11
)...Upper square version, (12)...Lower square version, (1
3)...Stretchable air bubble retaining material, (14)...Stretchable joint filler, (α)...Outer joint, (A)...Inner joint sub-agent Patent Attorney Kaihon Kyoumon Gai 2 Figure 1, Figure 2, Number 4

Claims (1)

[Claims] Insulating panels formed by stacking a pair of upper and lower rectangular panels so as to be staggered from each other in both vertical and horizontal directions are assembled and stacked on the inner peripheral surface of the outer shell of the storage tank above the static liquid level in the storage tank,
An outer joint that communicates with the inner peripheral surface of the outer shell is formed between the adjacent heat insulation panels, and an inner joint that has one end communicating with the outer joint and the other end opening into the storage tank, and the outer joint and the inner joint An emergency liquid-tight insulation structure for a low-temperature liquid storage tank, characterized in that each of the tanks is filled with an elastic filler and a bubble retaining material.