JPH0674394A - Coldness keeping structure of metallic tank for cryogenic storage - Google Patents

Abstract

PURPOSE:To prevent steel plates of a metal tank for cryogenic storage from cracking, etc., due to contraction even though the tank is for storing and carrying LNG, LEG, etc. at an ultra-low temp. CONSTITUTION:Glass wool 2a is affixed by a number of spindle adhering pins 8 attached to a steel plate 1 of a tank in its part of coldness keeping, and thereover glass cloth mesh 2b is affixed and fixed by a wire etc. Then hard polyurethane foam is sprayed to form the first urethane spray layer 3, and thereon a stainless steel wire meshing 4 is installed, and the second urethane spray layer 5 is formed by second spraying of hard polyurethane form. After hardening of the second urethane spray layer 5, a waterproofing agent spray layer 9 is formed by spraying the waterproofing agent, and a rock wool board 6 is fastened by pin. Finally the rock wool board 6 is covered with an iron plate 7 using a tiling fixture 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating structure for a metal tank for low temperature storage, and more particularly to a metal tank for storing those which need to be stored and transported at extremely low temperatures such as LNG and LEG. Regarding cold insulation structure.

[0002]

2. Description of the Related Art A conventional cold storage structure for a metal tank for low temperature storage of this type has a plate-shaped hard polyurethane attached to the surface of a tank steel plate, or a tank steel plate. The outer circumference was covered with a mold to pour a rigid polyurethane foam to form a heat retaining layer.

However, in such a cold insulation structure, L
When storage of NG, LEG, etc. is started and the temperature inside the tank becomes extremely low, the tank steel plate contracts greatly, stress is applied to the polyurethane layer due to the difference in expansion coefficient, and peeling occurs at the interface between the two. There is a problem that the heat insulation effect is likely to be lowered due to cracks in the polyurethane layer. In particular, in a large-sized tank mounted on a storage carrier such as LNG or LEG, the tank material contracts by about 1 cm per 10 m, which is a big problem.

Many proposals have been made to solve such problems. For example, in the technique disclosed in Japanese Patent Laid-Open No. 58-80071, a plurality of spacers made of a foam material made of hard synthetic resin are attached to the outer surface of a metal tank, and the foam material made of the same material having the same thickness is provided between the spacers. Spray it as a base layer, and then stick a glass net on the outside,
The structure is such that the hard synthetic resin foam material is sprayed again. However, in this technology, it is not possible to absorb the difference in the degree of shrinkage at the boundary surface between the tank material and the sprayed hard synthetic resin foam even with the interposition of the net, and the spacer and the sprayed hard synthetic resin foam Although peeling is likely to occur even at the boundary between the two, making it easier to construct and simplifying the process, the desired effect was not obtained for preventing the reduction of the heat insulation effect due to peeling or cracking.

In view of these conventional problems, the present invention is an LN.
An object of the present invention is to provide a cold storage structure for a metal tank for low temperature storage, which does not cause a problem due to contraction even in a metal tank for storage and transportation at extremely low temperatures such as G and LEG.

[0006]

[MEANS FOR SOLVING THE PROBLEMS] In order to achieve the above-mentioned object, the cold insulation structure for a metal tank for low temperature storage according to the present invention is
Glass wool is adhered to the outer surface of the tank steel plate, a glass cloth is adhered and fixed on the glass wool, a hard resin foam material is sprayed on the glass cloth, and the sprayed hard resin foam material is made of a corrosion-resistant metal. The wire mesh is attached, and the hard resin foam material is sprayed again on the wire mesh.

The cold storage structure of the metal tank for low temperature storage according to the present invention has a structure in which a plurality of layers of the hard resin foam material are formed by spraying the first hard resin foam material in a plurality of times. You can

The cold insulation structure of the metal tank for low temperature storage according to the present invention has a structure in which a plurality of layers of the hard resin foam material are formed by spraying the second hard resin foam material and performing the spraying operation a plurality of times. You can

The cold insulation structure of the metal tank for low temperature storage according to the present invention may be configured such that the hard resin foam material is a hard polyurethane foam.

The cold insulation structure of the metal tank for low temperature storage according to the present invention has the outermost layer surface of the second hard resin foam material,
A metal outer cover plate may be attached after spraying a waterproofing agent or a fireproof heat insulating agent.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged cross-sectional view of an upper cold insulation structure of a low temperature storage metal tank according to the present invention, FIG. 2 is an enlarged sectional view of a lower cold insulation structure of a low temperature storage metal tank according to the present invention, and FIG. FIG. 3 is a side view showing the external appearance of a metal tank for low temperature storage having the structure of FIG. 1 and FIG. 2. The tank shown in Fig. 3 is a LEG tank dedicated to the transportation of liquefied ethylene, with a total length of 30 meters and an overall height of 1
It is 0 number m.

The cold insulation structure of this embodiment will be described with reference to FIG. 1. In the figure, 1 is tank steel plate, 2a is glass wool, 2b is glass cloth mesh, 3 is a first urethane spray layer, 4 is stainless wire mesh, and 5 is The second urethane spray layer, 6 is a rock wool board, and 7 is an iron plate as an outer cover. Further, in the drawing, 8 is a spindle adhesive pin, 9 is a waterproof agent spraying layer, 10 is a tilement fitting for fixing an iron plate,
The total thickness except for tank steel plate 1 is about 25 at the top of the tank.
It is 0 mm and about 200 mm at the bottom of the tank. The thickness is set for the tank as shown in FIG. 1 and can be changed appropriately depending on the storage temperature, the size of the tank and the like.

Next, the procedure for constructing the structure according to this embodiment will be described. First, the upper part of the tank will be described with reference to FIG. 1. Oil and dust of the tank steel plate 1 in the cold insulation part except the pipe installation part are removed, and a large number of spindle bonding pins 8 are bonded or welded at predetermined intervals. Glass wool 2 on top
a is attached, fixed to the spindle adhesive pin 8, and the glass cloth mesh 2b is further attached thereon. In this example, the thickness of the glass wool 2a is 25 mm. Although not shown, a wire is rotated and fixed to the glass cloth mesh 2b.

Next, the first spraying of hard polyurethane foam is carried out to form a urethane spraying layer 3. The spraying of the rigid polyurethane foam has a thickness of 25 mm each time, and this is repeated 3 times to give a thickness of 75 mm.

Further, U is formed on the first urethane spray layer 3
The stainless wire mesh 4 is attached using a metal fitting (not shown) having a character shape. The mesh of the stainless steel wire net 4 may have a normal shape such as a hexagonal shape. After the stainless steel wire net 4 is attached, the second hard polyurethane foam is sprayed,
The urethane spray layer 5 is formed. Similar to the first urethane spray layer 3, the second spray of the rigid polyurethane foam has a thickness of 25 mm each time, and this is repeated 3 times to have a thickness of 75 mm.

After the second urethane spraying layer 5 is cured, a waterproofing agent (for example, Hull Coat: trademark) is sprayed to form the waterproofing agent spraying layer 9, and the rock wool board 6 is fixed with a pin (not shown). Rock wool board 6 has a thickness of 25
mm. And finally, the tilement bracket 10
Then, the rock wool board 6 is covered with the iron plate 7 and temporarily fixed with a band material or the like. In addition, it is necessary to partially rupture the second urethane spraying layer 5 and bury the tilement 11 in the mounting portion of the tilement fitting 10, as shown in FIG. Apply foam to rehearse. Tilement hardware 1
The embedding depth of 0 into the urethane spray layer 5 is about 25 mm.

Next, the lower part of the tank will be described with reference to FIG. Up to the attachment of the stainless steel wire net 4, it is almost the same as the above-mentioned tank upper part, but the thickness of the second hard polyurethane foam spraying is 25 mm per time, and this is repeated twice to repeat the second urethane spray layer 5a. 50
The thickness is mm.

In the illustrated embodiment, since the lower part of the tank is not covered with an iron plate, the second urethane spray layer 5
After curing a, the same waterproofing agent and fireproof heat insulating agent (for example, Duncoat: trademark) as described above are sprayed to form the waterproof agent / heat insulating agent sprayed layer 9a, and the rock wool board 6 is pinned. The upper and lower tanks may have the same cooling structure.

Finally, as shown in FIG. 3, a band iron 12 is hung from the iron plate 7 on the upper part of the tank to the lower part of the tank and fixed, and the construction is completed.

[0020]

As described above, the cold storage structure of the metal tank for low temperature storage according to the present invention has a metal mesh made of glass wool, glass cloth, hard resin foam material and corrosion resistant metal on the outer surface of the metal tank material. , A layer of hard resin foam,
Since it was formed by sequentially sticking, spraying, etc.,
There is almost no peeling or cracking of the heat insulating material or the heat insulating material due to shrinkage of the metal tank material at extremely low temperature, and the effect of reducing the cold insulating effect due to this is very small.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a cold insulation structure on an upper portion of a cold storage metal tank according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the cold insulation structure of the lower portion of the metal tank for cold storage according to the present invention.

FIG. 3 is a side view showing the appearance of a metal tank for low temperature storage having the structure shown in FIGS. 1 and 2.

[Explanation of symbols]

 1 Tank Steel Sheet 2 Glass Wool 3 First Urethane Spray Layer 4 Stainless Wire Mesh 5, 5a Second Urethane Spray Layer 6 Rockwool Board 7 Iron Plate 8 Spindle Adhesive Pin 9 Waterproof Agent Spray Layer 9a Waterproof Agent / Insulating Agent Spray Layer 10 Iron Plate Tilement fittings for fixing 11 Tilement 12 Steel band

Claims (5)

[Claims] 1. A glass wool is adhered to the outer surface of a tank steel plate, and a glass cloth is adhered and fixed on the glass wool,
Cold storage characterized in that a hard resin foam material is sprayed onto the glass cloth, a wire mesh made of a corrosion-resistant metal is attached onto the sprayed hard resin foam material, and the hard resin foam material is sprayed again from above the wire mesh. Cooling structure for metal tanks. 2. A spray of the first hard resin foam material,
The cold insulation structure for a metal tank for low-temperature storage according to claim 1, wherein a plurality of layers of the hard resin foam material are formed by performing a plurality of times. 3. Spraying the second hard resin foam material,
The cold insulation structure for a metal tank for low temperature storage according to claim 1 or 2, wherein a plurality of layers of the hard resin foam material are formed by performing the operation in plural times. 4. The cold insulation structure for a metal tank for low temperature storage according to claim 1, wherein the rigid resin foam material is rigid polyurethane foam. 5. The metal outer cover plate is attached after spraying a waterproofing agent or a fireproof heat insulating agent onto the outermost layer surface of the second hard resin foam material. Cold storage structure for metal tanks for cold storage.