JPH09118388A - Double-shell tank and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a double straight pipe, make impact resistance high, and reduce manufacturing costs. SOLUTION: An inner shell 11 is composed of an inner layer 11a, made of fiber reinforced resin, which serves as a corrosion-resistant layer, and an outer layer 11b which serves as a rigid layer. An outer shell 12 is made of fiber reinforced resin. The outer layer 11b of the inner shell 11 is formed by helically shaping a resin band-like body into a cylinder. The inner layer 11a of the inner shell 11 is formed by spray-up. The outer shell 12 is formed by wrapping fiber impregnated with resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double shell tank in which end plates are joined to both ends of a double straight tube composed of an outer shell and an inner shell, and a method for manufacturing the same, and more specifically, to a lightweight double straight tube. TECHNICAL FIELD The present invention relates to a double-shell tank and a method for manufacturing the same, which is resistant to impact while being manufactured, and which can be easily manufactured to reduce the manufacturing cost.

[0002]

2. Description of the Related Art A tank made of fiber reinforced resin called a double-shell tank is shown in FIG.
And a portion of the bowl-shaped end plate 120 that closes both ends of the double straight pipe portion 110. Double straight pipe section 110
Manhole 130 is attached to the center of the upper part of
Further, a leak detection tube 131 is arranged from the top to the bottom. The shell wall of the double straight pipe part 110 is roughly divided into an inner shell 111 and an outer shell 112.

In such a tank, a part of an annular space formed between an inner shell 111 and an outer shell 112 is porous as disclosed in Japanese Patent Application Publication No. 505375 in 1993. Some have a core. The inner shell 111 and the outer shell 112 are formed of a fiber reinforced resin, and the porous core is manufactured from a raw material such as high density polyethylene net or jute in the form of matting, net, screen or mesh.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The tank disclosed in Japanese Patent Publication No. 505375 in 1993 has an inner shell 1
Since 11 and 112 are made of fiber reinforced resin, the weight is reduced as compared with a steel tank, but further weight reduction is desired in the work of burying the tank in the ground.

That is, at the site where the tank is installed, the tank is buried by unloading and unloading the tank with a heavy machine such as a crane. At that time, when the tank comes into contact with the surroundings, an impact force is applied to the tank. At this time, if the weight of the tank is large, the impact force applied to the tank also becomes large. Then, since the fiber-reinforced resin has a small allowable strain, fine cracks may occur in the inner and outer shells 111 and 112 made of the fiber-reinforced resin. Since minute cracks are hard to see, a defective tank is buried in the ground as it is and the aqueous solution is stored in the tank. Then, the aqueous solution in this tank leaks from the crack.

As a method of manufacturing the double straight pipe section 110, filament winding (FW method) molding in which a fiber reinforced resin material is sprayed or wound around a rotating iron inner mold is considered. However, in such a method, if the diameter of the tank is about 2 m, it takes time and effort to demold the inner mold for molding the double straight pipe section 110 and the product, and the manufacturing cost increases.

Further, when the double straight pipe part 110 and the end plate 120 are joined to manufacture an integrated tank, the end plate of the double straight pipe part 110 is mainly used for the inner shell 111 which exhibits rigidity. By joining the inner layers of the double straight pipe part 11
It is necessary to strengthen the bonding force between 0 and the end plate 120. Therefore, at both ends of the double straight pipe portion 110, the outer shell 112 is peeled off to expose the outer peripheral surface of the inner shell 111, and the inner shell 11
The inner and outer surfaces of No. 1 and the inner and outer surfaces of the rigid layer of the end plate 120 must be strongly bonded. However, in order to expose the outer peripheral surface of the inner shell 111, it is necessary to grind both end surfaces of the double straight pipe section 110, and this work is very troublesome.

Therefore, the present invention is light-weight, strong against impact, and easy to manufacture to reduce the manufacturing cost, and further adheres to the inner shell at the end of the double straight pipe portion. An object of the present invention is to provide a double-shell tank in which the outer shell that is formed can be easily peeled from the inner shell, and a manufacturing method thereof.

[0009]

[Means for Solving the Problems] A first means for solving the above-mentioned problems is to use a double shell tank in which end plates are joined to both ends of a double straight pipe consisting of an inner shell and an outer shell. A film forming layer and / or a spacer is interposed between the shell and the outer shell,
The double-shell tank is characterized in that the inner shell outer layer is formed of a synthetic resin, the inner shell inner layer is laminated on the inner surface of the inner shell outer layer with a fiber-reinforced resin, and the outer shell is formed of resin-impregnated fiber.

According to the above-mentioned first means, the inner shell outer layer is made of a synthetic resin having a large specific gravity and becomes a rigid layer, but since the ratio of the inner shell outer layer to the double straight pipe is small, the weight can be reduced. Planned. Further, the inner layer of the inner shell laminated with the fiber reinforced resin on the inner surface of the outer layer of the inner shell serves as a corrosion resistant layer, and exhibits an anticorrosive action against the aqueous solution stored in the tank. Furthermore, since the outer shell is made of resin-impregnated fiber, impact resistance is enhanced. According to this means, the inner shell and the outer shell are separated by the film forming layer or the spacer. Further, by interposing a spacer between the inner shell and the outer shell, the outer shell can be easily peeled from the inner shell.

A second means for solving the above-mentioned problems is a method for manufacturing a double-shell tank in which end plates are joined to both ends of a double straight pipe consisting of an inner shell and an outer shell. A body is formed into a spiral shape to form a belt-made cylindrical body to be the inner shell outer layer, and in parallel with this, the inner surface of the belt-made cylindrical body is sprayed with a fiber reinforced resin to laminate the inner shell inner layer, At the same time, a film-forming layer and / or a spacer is laminated on the outer surface of the strip-shaped cylinder, and a resin-impregnated fiber is wound around the outer surface of the film-forming layer or the spacer to form an outer shell. Is a manufacturing method.

According to the above-mentioned second means, since the corrosion-resistant layer is laminated in parallel with the formation of the belt-shaped cylindrical body, it is not necessary to remove the core-type mold set or the product, and the double-layer of the large diameter is used. Not only can the shell tank be easily manufactured, but the productivity is improved. In addition, the band-shaped cylindrical body formed by spirally shaping a synthetic resin band-shaped body has an inner shell inner layer formed by spraying resin-reinforced fibers on the inner surface of the band-shaped cylindrical body to strengthen the bonding force.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. 1 to 7 by taking an example of manufacturing a double shell tank. FIG.
FIG. 4 is a cross-sectional view of a shell wall of a double straight pipe section of a double shell tank according to the present invention. FIG. 2 is a partial cross-sectional perspective view of the resin strip. FIG. 3 is a schematic perspective view showing the method for manufacturing the double-shell tank according to the present invention. FIG. 4 is a perspective view of the double straight pipe part. FIG. 5 is a cross-sectional view of a double straight pipe section showing a different embodiment. FIG. 6 is a cross-sectional view showing a joined state of the double straight pipe portion and the end plate. FIG. 7 is a cross-sectional view of a double straight pipe part showing a different embodiment.

The outer shape of the double shell tank according to the present invention is
This is the same as that of the above-mentioned conventional technique, and is divided into a double straight pipe portion 10 and a portion of the end plate 30 as shown in FIG. The layer structure of the shell wall of the double straight pipe section 10 is roughly divided into an inner shell 11 and an outer shell 12, as shown in FIG. Inner shell 1
1 is further divided into two layers, an inner shell inner layer 11a formed of a fiber reinforced resin and an inner shell outer layer 11b formed by spirally shaping a resin belt-like body to form a belt-made cylindrical body. It has a layered structure. On the other hand, the outer shell 12 mainly functions as a leak-proof layer and is made of a fiber-reinforced resin. A film forming layer 13 is interposed between the inner shell 11 and the outer shell 12.

Both the inner shell inner layer 11a and the outer shell 12 are made of a fiber or particle reinforced resin and serve as corrosion resistant layers designed to withstand the inner and outer pressures. Further, the outer shell 12 has a role as a leak-proof layer for preventing the liquid accumulated between the inner shell 11 and the outer shell 12 from leaking to the outside, and cracks or the like are generated due to impact during transportation. It is necessary to withstand scratches and the like. Therefore, the thickness of the outer shell 12 is set to 2 to 5 mm so as to have appropriate softness. The outer periphery of the outer shell 12 can be reinforced by protruding ribs, but in consideration of backfilling when the tank is buried, it has a proper softness so that it can withstand impacts and the like. A tubular shape is desirable.

The inner shell outer layer 11b between the inner shell inner layer 11a and the outer shell 12 functions as a rigid layer, and is formed by a band-shaped cylindrical body formed by spirally shaping a resin band-shaped body 21 as shown in FIG. Form. The cross-sectional shape of the resin strip 21 is shown in FIG.
It may be a flat rectangle such as
As in (c), the ribs 8 and 9 for reinforcement may be provided on the surface. The ribs 8 and 9 projecting as shown in FIGS. 2 (b) and 2 (c) have the disadvantage that they have a large section modulus per weight, are light, and have high rigidity, although they have the drawback of being difficult to shape. . Tree strip 6 of FIG. 2 (c)
Is a rib 9a provided at one end of many ribs
Has a low height and a rounded tip portion to form a fitting protrusion. Further, among the many ribs, the rib 9b provided at the other end has a groove on the back surface side. When the resin strip 6 is rolled into a tubular shape, the rib 9a
The fitting protrusion of is fitted into the concave groove of the rib 9b and shaped into a tube. The resin band 21 has a wide selection range of thickness 5 to 25
Although it is possible to have a size of about 10 mm, particularly when manufacturing a double-shell tank to be buried, if it is set to about 10 to 17 mm, a tubular shape can be reasonably formed.

As the material of the resinous band 21, a thermoplastic resin such as vinyl chloride resin, methacrylic resin, urethane resin, or a fiber reinforced resin obtained by pultrusion may be used. However, in terms of cost,
Vinyl chloride resins are preferred.

Inner shell outer layer 1 formed from a resin band 21
The film forming layer 13 interposed between 1b and the outer shell 12 is
Wrap a band-shaped film forming material 23, preferably 0.03 ~
Form with a thickness of 0.3 mm. As the material of the film forming material 23, polyethylene, polyvinyl chloride, polypropylene,
Polyethylene terephthalate, polyvinyl alcohol,
Thermoplastic films such as ethylene vinyl acetate can be used. However, it is desirable to use polyethylene, polypropylene, polyvinyl alcohol, or the like, which is a material that does not adhere to the outer shell 12, as the band-shaped film forming material 23.

The film forming layer 13 may be formed by spraying a quick-drying material instead of the band-shaped film forming material 23 or by winding a sheet material. As the quick-drying material, it is desirable to use a general coating material or a thermoplastic material dissolved in a solvent, or a polyvinyl alcohol material. As the coating material, acrylic, urethane-based, silicon, or fluorine-based material can be used, but it is preferable to use silicon, a fluorine coating material, or a polyvinyl alcohol material that does not adhere to the outer shell 12. When a sheet material is used, polyethylene, polypropylene or polyvinyl chloride is molded like a foam material or a plate material. The wall thickness when using the sheet material is preferably 3 to 7 mm.

In any case, by forming the film forming layer 13 with the above materials, the inner shell 11 and the outer shell 12 do not adhere to each other, and the double straight pipe portion 10 becomes a double shell.

The double shell tank according to the present invention is constructed as described above, and a method of manufacturing this double shell tank will be described with reference to FIG. The method for manufacturing a tank of the present invention is performed by using a pipe making machine 40 and the like as shown in FIG. The pipe-making machine 40 is one in which the resin band-shaped body 21 is sequentially fed out and deformed into a spiral shape to form a band-shaped cylindrical body 45.

The method of manufacturing the tank of the present invention will be described in order. The resin strip 21 is introduced into the pipe making machine 40 described above.
The cylindrical body 4 made of strip according to the diameter of the tank to be formed
5 is formed. The belt-made cylindrical body 45 becomes the inner shell outer layer 11b that functions as a rigid layer.

Inside the inner shell outer layer 11b, an inner shell inner layer 11a which functions as a corrosion resistant layer is formed. Inner shell inner layer 11a
Is a mixture of short fibers 22a obtained by cutting the roving 22 into a length of 1/2 to 4 inches by a cutter 42 and a fiber reinforced resin having a good resin retention ratio, which is sprayed to the inner shell outer layer 11b by a spray layup gun 41. Stack. The thickness of the inner layer 11a of the inner shell is 3 to 3 for the purpose of anticorrosion effect.
About 7 mm is desirable. By setting the length of the cut fiber to about 2 inches, high strength can be exhibited.
The resin sprayed from the spray layup gun 41 is an unsaturated polyester resin, a vinyl ester resin,
Thermosetting resin such as epoxy resin can be used.

The cylindrical inner shell 11 thus formed
A strip-shaped coating film forming material 23 is wound around the outer surface of the above, and the film forming layer 13 is laminated. The film forming material 23 can be laminated in a continuous spiral shape by allowing the inner shell 11 to move while rotating about the central axis as a rotation axis.

The outer shell 12 is formed by laminating the resin-impregnated fibers 24 on the outer periphery of the film forming layer 13 with a thickness of preferably about 2 to 5 mm. The resin-impregnated fiber 24 can be laminated in a continuous spiral shape on the outer periphery of the film forming layer 13 rotating around the central axis by using a band-shaped member.

The resin-impregnated fiber 24 forming the outer shell 12 is
The resin-impregnated strip-shaped roving long fibers 24a are mixed with short fibers 24b obtained by cutting the roving into 1/2 to 4 inches by a cutter 43 and impregnating the resin. The material of the roving long fiber 24a and the short fiber 24b is inorganic fiber such as glass fiber or carbon fiber, or organic fiber such as aramid fiber or PET fiber. When the length of the short fibers 24b is about 2 inches, high strength can be exhibited. In addition, the resin-impregnated fiber 24
A roving cloth tape and a shaving tape are also added to the tape as needed for strength.

The resin with which the resin-impregnated fiber 24 is impregnated is a thermosetting resin such as an unsaturated polyester resin, a vinyl ester resin, or an epoxy resin, like the resin forming the inner shell inner layer 11a. When the resin impregnated in the resin-impregnated fiber 24 is cured, the roving long fiber 24a is cured and the short fiber 24 is attached to the surface of the hoop layer.
The outer shell 12 composed of b and the hardened chop layer is formed, and the long laminated cylindrical body 20 is continuously formed. When this long laminated cylindrical body 20 is cut into a predetermined length by a cutter or the like (not shown), the double straight pipe portion 10 is completed.

Then, the end plates 30 are bonded to both ends of the double straight pipe portion 10 by hand layup. The end plate 30 is formed by stacking an inner shell 31 and an outer shell 32 with a gap therebetween.
The inner shell 31 and the outer shell 32 of the end plate 30 are bonded to the inner shell 11 and the outer shell 12 of the double straight pipe portion 10, respectively. However, since the inner shell 11 of the double straight pipe portion 10 is a layer that exerts strength, the inner shell 11 of the double straight pipe portion 10 and the inner shell 11 of the end plate 30 are more firmly bonded. Is preferable.

Therefore, in the double straight pipe portion 10, as shown in FIG. 4, only the outer shells 12 at both ends are peeled off so that the inner shell 11 is exposed. Inner shell 11 of double straight pipe section 10 and end plate 30
The inner shell 11 is adhered from both inside and outside. Since the film forming layer 13 is interposed between the inner shell 11 and the outer shell 12 of the double straight pipe portion 10 and the inner shell 11 and the outer shell 12 are not adhered to each other by the film forming layer 13, The shell 12 is easily peeled off from the inner shell 11.

However, in order to allow the outer shell 12 to be more easily peeled from the inner shell 11, the outer surface of the film forming layer 13 or the film forming layer 13 as shown in FIG.
A spacer (peeling member) 25 may be laminated on the outer surface of the inner shell 11 over the entire length of the double straight pipe portion 10. As a material of the spacer (peeling member) 25, corrugated paper, polyethylene, polypropylene, a polyester-polyethylene copolymer, a urethane foam, a corrugated plate, or the like can be used. Single-sided corrugated paper has the advantages that it is inexpensive, can be easily shaped, and has a large thickness. The thickness of the spacer (peeling member) 25 is preferably about 3 to 10 mm. By interposing such a spacer (peeling member) 25 between the inner shell 11 and the outer shell 12, the outer shell 12 is more easily peeled off, and the inner shell 12 is more easily exposed.

After the inner and outer surfaces of the inner shell 11 exposed by peeling off the outer shell 12 of the double straight pipe portion 10 and the both surfaces of the inner shell 11 of the end plate 30 are adhered to each other, as shown in FIG. Straight pipe part 10
When the outer shell 12 and the outer shell 12 of the end plate 30 are bonded together, the double straight pipe portion 10 and the end plate 30 are firmly integrated.

Double straight pipe portion 10 in which this end plate 30 is integrated
When a manhole (not shown) is attached to the top of the and the leak detection structure (not shown) is attached to the double straight pipe portion 10, the double shell tank is completed. The leak detection structure is one in which a pipe is inserted into the double-shell tank from a flange attached to the upper part of the double-shell tank. The tip of the pipe shall be fixed to the bottom of the double shell tank so that the liquid accumulated between the inner shell 11 and the outer shell 12 at the bottom can pass through.

The present invention is not limited to the above-mentioned embodiment, and the design can be changed within the scope of the present invention. For example, the film forming layer 1 inside the inner shell 11 and the outer shell 12
As shown in FIG. 7, a fiber-reinforced resin layer 14 corresponding to the strength is laminated between the layers 3 and 3. The resin of the fiber reinforced resin layer 14 may be the same as the resin forming the outer shell 12. However, the roving continuous fibers 24a may be simply wound for the purpose of only strengthening the rigidity in the circumferential direction.

Further, as the fiber reinforced resin forming the inner shell inner layer 11a and the outer shell 12, a particle reinforced resin in which particles are mixed between fiber reinforced resins can be used. The types of particles include silica sand, mountain sand such as hard sandstone, calcium carbonate, talc, aluminum hydroxide, and a crushed material of waste plastic. In particular, it is desirable to mainly use a crushed material of sand or plastic in view of the contribution ratio of rigidity to cost. When using sand, consider adhesion with resin,
Perform silane coupling treatment. Although the physical properties of the particles may vary depending on the wall thickness, it is desirable to use a blend of 1,000 to 5,000 μm of main aggregate, 500 μm or less of fine aggregate and about 2 μm of calcium carbonate as fine particles.

[0035]

EXAMPLES Examples for confirming the effects of the present invention will be described below. As a first example of the method for manufacturing a composite pipe according to the present invention, a tank was manufactured using the materials shown in Table 1.

[0036]

[Table 1]

In Example 1, a polyethylene tape having a thickness of 0.03 mm was used to form a film forming layer as shown in FIG. In this embodiment, a resin band-shaped body is shaped into a pipe having a diameter of 2 m by a pipe making machine to continuously form a pipe shape, and the inner surface thereof is spray-laid up to 6 mm.
A thick inner shell was formed. Then, a 0.03 mm polyethylene tape was wound around the outer circumference of the inner shell to form a film-forming layer. An outer shell formed by laminating a chop layer and a hoop layer to a thickness of 3 mm was formed on the outer periphery of the film-forming layer to form a laminated cylindrical body, which was sized to form a double straight pipe portion.

End plates were adhered to both ends of such a double straight pipe portion to complete a double shell tank having a diameter of 2 m, a length of 6 m and a capacity of 20 kiloliters. This double shell tank has internal pressure
It passed the pressure test of 0.98 kg / cm ² , and the weight was reduced by about 20% compared to the FRP product.

Further, as a second embodiment of the method for producing a composite pipe according to the present invention, a tank was produced using the materials shown in Table 2.

[0040]

[Table 2]

Example 2 uses a single-faced corrugated paper with a thickness of 5 mm manufactured by Kaizu Misato Co., Ltd., as shown in FIG.
A spacer (peeling member) is interposed between the inner shell and the outer shell of the double tube. In this embodiment, a resin band-shaped body is shaped into a pipe having a diameter of 2 m by a pipe making machine, and while continuously producing a pipe shape, the inner surface thereof is spray-laid up to 3 m.
A mm thick inner shell was formed. On the outer circumference of the inner shell, as described above, the single-faced corrugated paper to be the spacer (peeling member) was wound over the entire length. On the outer circumference of the inner shell including the outer circumference of the spacer (peeling member), a chop layer and a hoop layer are laminated in a thickness of 3 mm to form an outer shell to form a laminated cylindrical body, which is sized and cut into double layers. The straight pipe part was molded.

The outer shell of both ends of this double straight pipe section is 20
It was peeled off by 0 mm to expose the outer layer of the inner shell, that is, the surface of the strip cylinder. At this time, the outer shell is a spacer (peeling member)
Easily peeled from the inner layer. The exposed inner shell is
We have secured a minimum adhesive length of approximately 150 mm. End plates are attached to both ends of such a double straight pipe part, and the diameter is 2 m and the length is 6 m.
Completed a double-shell tank with a capacity of 20 kiloliters. This double-shell tank passed the pressure test with an internal pressure of 0.98 kg / cm ² , and the weight was reduced by about 20% compared to the FRP product.

Further, as a third embodiment of the method for manufacturing a composite pipe according to the present invention, a tank was manufactured using the materials shown in Table 3.

[0044]

[Table 3]

In Example 3, another fiber-reinforced resin layer was provided between the band-shaped cylinder and the outer shell, that is, in the outermost layer of the inner shell. Then, a polyethylene tape with a thickness of 0.03 mm is used as a film forming material to form a film forming layer, and a 5 mm-thick single-faced corrugated paper made by Kaizu Misato Co., Ltd. is used to form an inner shell and an outer shell. A spacer (peeling member) is interposed between the two. In this embodiment, a resin band-shaped body is formed into a diameter of 2 m by a pipe making machine and continuously formed into a pipe shape, and the inner surface thereof is spray laid up to 3 mm.
A thick inner layer was formed. Also, on the outer surface of the belt-shaped cylinder,
A fiber reinforced resin layer that strengthens only in the circumferential direction was formed, and an inner shell having the fiber reinforced resin layer was formed on the inner and outer surfaces of the band-shaped cylinder. A polyethylene tape was wound around the outer circumference of the inner shell to form a film forming material layer. However, before winding the polyethylene tape, the inner layer of the inner layer was wound without curing. A single-sided corrugated paper which serves as a spacer (peeling member) was wound around the outer circumference of the film forming layer over the entire length. Then, a chop layer and a hoop layer were laminated on the outer periphery of the spacer (peeling member) to a thickness of 3 mm to form an outer shell to form a laminated cylindrical body, which was cut into dimensions to form a double straight pipe portion.

Both ends of this double straight pipe part are 200m only in the outer layer
It was peeled off to expose the outer layer of the inner shell. At this time, the outer shell was easily peeled from the inner layer by the spacer (peeling member). The exposed part of the inner shell has a minimum adhesive length of approximately 150 m.
m secured. End plates were adhered to both ends of such a double straight pipe portion to complete a double shell tank having a diameter of 2 m, a length of 6 m and a capacity of 20 kiloliters. This double shell tank has an internal pressure of 0.
Passed the pressure test of 98 kg / cm ² . In addition, the double-shell tank of Example 3 has a thinner inner layer as compared with Example 1, and the outer surface of the resin strip is reinforced accordingly, so that the tank has almost the same rigidity. Was given. And
Since both the inner surface and the outer surface of the resin strip can be reinforced, the production rate could be increased by 1.5 times.

[0047]

The method of manufacturing a tank of the present invention has an effect that the shell wall of the straight pipe portion can be easily manufactured, and in particular, the end portion of the straight pipe portion is made of a rigid layer. The cylindrical body can be easily exposed, and the joining work with the mirror portion is smooth.

The tank manufactured according to the present invention is
Compared to the conventional tank made of fiber reinforced resin, it has the same rigidity but is lighter in weight. Therefore,
When burying a tank on-site, large heavy equipment is not required for installation, and workability can be improved.

Further, according to the manufacturing method of the present invention, since the straight pipe portion of the tank can be manufactured with almost no manpower,
Labor costs can be reduced. Therefore, the cost of the large tank can be reduced.

In addition, in the tank of the present invention, since the outer layer of the inner layer has a large allowable strain, the inner layer is not damaged and is not cracked even when it is buried, even when it is locally impacted. Also disappears. Therefore, the solution in the tank does not leak, and the structure can be made safer.

[Brief description of the drawings]

FIG. 1 is a sectional view of a shell wall of a double straight pipe portion of a double shell tank according to the present invention.

FIG. 2 is a partial cross-sectional perspective view of a resin strip.

FIG. 3 is a schematic perspective view showing a method for manufacturing a double-shell tank according to the present invention.

FIG. 4 is a perspective view of a double straight pipe part.

FIG. 5 is a cross-sectional view of a double straight pipe portion showing a different embodiment.

FIG. 6 is a cross-sectional view showing a joined state of the double straight pipe portion and the end plate.

FIG. 7 is a cross-sectional view of a double straight pipe portion showing still another embodiment.

FIG. 8 is a sectional view of a conventional double shell tank.

[Explanation of symbols]

 10 Double Straight Pipe Section 11 Inner Shell 11a Inner Shell Outer Layer 11b Inner Shell Inner Layer 12 Outer Shell 13 Film Forming Layer 14 Fiber Reinforced Resin Layer 21 Resin Strip 24 Resin Impregnated Fiber 25 Spacer (Peeling Member) 30 End Plate 31 Inner Shell 32 shell

Claims (2)

[Claims] 1. In a double-shell tank in which end plates are joined to both ends of a double straight pipe consisting of an inner shell and an outer shell, a film forming layer and / or a spacer is interposed between the inner shell and the outer shell. A double-shell tank, wherein the inner shell outer layer is formed of a synthetic resin, the inner shell inner layer is laminated on the inner surface of the inner shell outer layer with a fiber reinforced resin, and the outer shell is formed of resin-impregnated fiber. 2. A method for producing a double-shell tank in which end plates are joined to both ends of a double straight pipe having an inner shell and an outer shell, wherein a synthetic resin strip is spirally shaped to form an inner shell outer layer. A belt-shaped cylindrical body to be formed is formed, and in parallel with this, a fiber reinforced resin is sprayed on the inner surface of the belt-shaped cylindrical body to laminate an inner shell inner layer, and at the same time, a film is formed on the outer surface of the belt-shaped cylindrical body. A method for producing a double-shell tank, comprising laminating layers and / or spacers, and winding resin-impregnated fibers around the outer surface of the film-forming layer or spacers to form an outer shell.