JPH1182887A - Pressure vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the reliability of an airtight seal between a synthetic resin liner and a metal mouthpiece in a pressure vessel. SOLUTION: In a pressure vessel provided with a synthetic resin liner 2 and a metal mouthpiece body 10, the mouthpiece body 10 is so disposed that a boss part 11 pierces the liner 2 and that a flange part 12 is positioned on the inner surface side of the liner 2. An air hole 19 with one end communicating with the inside of the liner 2 and with the other end opened to a liner facing face 12a of the flange part 12 is formed in the flange part 12. The liner facing face 12a is additionally provided with an air pressure valve 26 of annular plate shape so as to cover the other end opening of the air hole 19, and the liner facing face 12a is additionally provided with an elastic sealant 18 of annular plate shape so as to cover the air pressure valve 26. The elastic sealant 18 is pressed hard to the inner surface of the liner 2 by the internal pressure of charged compressed natural gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various compressed gases such as CNG (compressed natural gas), LNG (liquefied natural gas), and LNG.
The present invention relates to a pressure vessel for filling various liquefied gases such as PG (liquefied petroleum gas) and other various pressurized substances.

[0002]

2. Description of the Related Art Conventionally, as a CNG pressure vessel 60,
As shown in FIG. 9, a liner 61 made of a synthetic resin that does not allow CNG to permeate, and an outer FRP (fiber reinforced resin) reinforcing layer 65 that enhances pressure resistance and satisfies a pressure resistance standard of 600 kg / cm ² is considered. The weight is reduced by sharing the roles of both layers. The liner 61 has a cylindrical peripheral wall portion 62 and a curved end wall portion 63 closing both ends thereof.
Are integrally formed of a synthetic resin. When a seamless liner is required for the liner 61, the liner molding method is limited to rotational molding or blow molding.

[0003] At the center of one end wall 63, a metal base 70 for connecting a joint (not shown) for pipe connection is attached. The base 70 has a liner 61.
, A flange 72 protruding from the inner periphery of the boss 71, and a fastening member 73 screwed to the inner periphery of the boss 71. Liner 61 is base 70
The airtight seal between the two 61 and 70 is achieved by being adhesively molded. Further, a step 74 is provided on the inner periphery of the boss 71, and the end of the liner 61 wrapping around the step 74 is fastened by a fastening member 73 to improve the airtight seal.

In order to rotationally mold the liner 61, first, as shown in FIG. 10, a die 70 is set in a mold 66, and the mold 66 is heated by a furnace (not shown). 6
Reference numeral 8 denotes a plug of the base 70. While rotating the mold 66, a polyethylene or nylon synthetic resin powder is charged into the inside thereof, and the synthetic resin powder is adhered to the mold 66 and the inner surface of the flange portion 72 to be melted.
1 is rotationally molded. When the liner 61 is hardened by cooling, the liner 61 with the base 70 is removed from the mold, and as shown in FIG. It is tightened by the tightening member 73. When the FRP reinforcing layer 65 is formed by helically winding and hoop winding glass fiber around the outer periphery of the liner 61 and impregnating and fixing the same with an epoxy resin, the pressure vessel 60 is completed.

[0005]

However, in the pressure vessel 60, the pressure of the synthetic resin during the rotational molding of the liner 61 is low, and the polyethylene or nylon used for the liner 61 is made of metal. Lack of adhesiveness, the adhesive surface may be peeled off due to a difference in material shrinkage after rotational molding described later, and the tightening portion of the liner 61 by the tightening member 73 is so small that it is difficult to adjust the interference. However, the reliability of the hermetic seal between the liner 61 and the base 70 was lacking.

Further, since the thermal expansion coefficient of the liner 61 made of synthetic resin is one order of magnitude larger than the thermal expansion coefficient of the metal base 70,
The part of the liner 61 attached to the flange part 72 has a large temperature drop in cooling after rotational molding,
A large difference in material shrinkage from the flange 72 occurs, and residual strain and residual stress in the tensile direction are inherent. For this reason, when the pressure vessel 60 is used (especially when used at a low temperature), if a temperature difference due to a change in air temperature is repeated, a crack 67 may be generated in the same portion of the liner 61 as shown in FIG. In some cases, the crack 67 has a problem that the hermetic seal is substantially lost.

Also, the end of the liner 61 that has wrapped around the step 74 during rotational molding has low shape accuracy as it is,
Since it is not tightly tightened by the tightening member 73, it is necessary to precisely cut the end. In addition, there is also a problem that since the cutting chips at that time always enter the liner 61, a troublesome removal operation is required.

An object of the present invention is to solve the above-mentioned problems and to provide a pressure vessel which can improve the reliability of an airtight seal between a synthetic resin liner and a metal base.

[0009]

In order to solve the above-mentioned problems, a pressure vessel according to the present invention comprises a liner made of synthetic resin, a cylindrical boss portion, and a flange portion projecting from the outer periphery of the boss portion. A pressure vessel in which the base body is disposed so that the boss portion penetrates the liner and the flange portion is located on the inner surface side of the liner, and one end of the flange portion is inside the liner. A communication hole is formed at the other end of the communicating portion, the opening being formed on the liner-facing surface of the flange portion. An annular sealing material is provided on the surface facing the liner so as to cover the air pressure valve, and the elastic sealing material is brought into contact with the inner surface of the liner.

Further, it is preferable to add the following means (1) to (4). (1) An annular groove is provided on the surface of the air pressure valve facing the flange. (2) An annular ridge is provided on the surface of the pneumatic valve facing the elastic sealing material. (3) The inner and outer peripheries of the elastic sealing material are provided one size larger than the air pressure valve, and the inner and outer peripheries of the elastic sealing material protruding from the air pressure valve are joined to the liner-facing surface of the flange portion. (4) A ring plate is provided on the outer periphery of the boss portion and is in contact with the outer surface of the liner, and the ring plate is fastened to the flange portion via the liner.

The pneumatic valve is preferably formed of a metal plate having a thickness of about 0.1 to 0.5 mm, and more preferably formed of a non-rusting stainless steel plate. Examples of the elastic sealing material include heat-resistant and gas-permeable rubbers such as silicon rubber, EPDM rubber, and fluorine rubber, and adhesives that have elasticity even after being cured.

The method of forming the liner is not particularly limited, but when a seamless liner is required, rotational molding or blow molding is employed. The synthetic resin for forming the liner is not particularly limited, and examples thereof include polyethylene, nylon, polypropylene, ABS, saturated polyester, polyamide, polycarbonate, and the like, or a mixture of these with reinforcing fibers.

The liner is preferably reinforced by covering the entire outer surface thereof with a reinforcing layer such as an FRP reinforcing layer. FR
The material of the fiber for P is not limited to a specific material as long as it has a reinforcing property. Glass, carbon, poly-p-phenylene terephthalamide, nylon, polyethylene,
Examples include polyester and the like. Examples of the synthetic resin for impregnating and fixing the fibers include epoxy, vinyl ester, unsaturated polyester and the like.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a CNG pressure vessel will be described below with reference to FIGS. As shown in FIG. 1, the pressure vessel 1 of the present embodiment covers a liner 2 made of synthetic resin, bases 6 and 7 attached to end walls 4 on both sides of the liner 2, and the entire outer surface of the liner 2. And an FRP reinforcing layer 8 that reinforces the FRP.

As shown in FIG. 1, a liner 2 which forms an inner layer of a pressure vessel 1 has a cylindrical peripheral wall portion 3 and a curved end wall portion 4 closing both ends thereof, which are integrally formed by a polyethylene resin without a seam. It is molded. The dimensions of the liner 2 are, for example, 220 mm in inner diameter and 900 mm in inner dimension.

At the center of the right and left end walls 4, metal bases 6, 7 are attached. The base 6 on the right is
Joint attached to the end of CNG piping (not shown)
Is connected to the outside, and the base 7 on the left side is a side to which the joint is not connected.

The right base 6 is a liner 2 (end wall 4).
A metal base body 10 including a cylindrical boss portion 11 penetrating through and a flange portion 12 protruding from the inner end side outer periphery of the boss portion 11 and located on the inner surface side of the liner 2, and an outer periphery of the boss portion 11 A ring plate 13 which is externally inserted and abuts against the outer surface of the liner 2 and a male screw portion 14 formed on the outer periphery of the outer end side of the boss portion 11 are screwed to the ring plate 13 via the liner 2 to the flange portion 12. Lock nut 15 to be tightened
And The CNG passage 16 is formed on the inner periphery of the boss 11, and a female thread 17 for connecting the joint is formed on the inner periphery on the outer end side.

One end of the flange portion 12 is
There are formed three vent holes 19 which are open at the inner periphery of the liner 2 and communicate with the inside of the liner 2, and whose other ends are opened at the liner-facing surface 12 a of the flange portion 12 at intervals of, for example, 120 degrees. A vent hole 19 is formed in the liner facing surface 12a of the flange portion 12.
A ring-shaped pressure valve 26 is attached so as to cover the other end of the elastic seal material, and a ring-shaped elastic seal material 18 is further provided by molding to cover the pressure valve 26.
8 is in contact with the inner surface of the liner 2.

The pressure valve 26 has a thickness of about 0.2 m, for example.
m, and three annular curved portions are pressed concentrically at small intervals, so that the three annular grooves 27 are viewed from the surface facing the flange portion, and are viewed from the surface facing the elastic sealing material. Three annular ridges 28 are respectively provided at the same time.

The elastic seal member 18 is made of, for example, fluorine rubber, and its inner and outer circumferences are provided one size larger than the atmospheric pressure valve 26. The inner peripheral edge portion 18a of the elastic sealing material 18 that has protruded from the air pressure valve 26 extends from the liner-facing surface 12a of the flange portion 12 to the outer peripheral surface of the boss portion 11, and the outer peripheral edge portion 18b that protrudes from the liner-facing surface 12a.
a from the protrusion 12b provided on the outer peripheral portion of the
Are vulcanized and bonded at the time of the molding. Since the adhesive strength is very strong, the flange 1
A perfect hermetic seal is provided between the elastic seal material 2 and the elastic seal material 18.

On the other hand, between the liner 2 and the elastic sealing material 18, a necessary and sufficient airtight seal is achieved by the combination of the following operations (1), (2) and (3). B) The liner 2 is adhered to the elastic sealing material 18 at the time of rotational molding of the liner described later. However, since the adhesive strength is weak, an airtight seal cannot be obtained only by bonding. B) The ring plate 13 is pressed against the liner 2 by screwing the lock nut 15, and the space between the liner 2 and the elastic sealing material 18 is tightened. C; When CNG is filled in the liner 2, CNG
Internal pressure is applied to a part of the surface of the air pressure valve 26 facing the flange portion through the three vent holes 19, and the three annular grooves 2.
In order to reach the entire circumference of the surface of the air pressure valve 26 facing the flange portion via 7, the air pressure valve 26 is pushed up, and thus the elastic sealing material 18 is pushed up. Since the inner and outer peripheral edges 18a and 18b are vulcanized and bonded to the flange portion 12, the elastic sealing material 18 is pushed up so that the central portion between the inner and outer peripheries protrudes and is pressed against the liner 2. The pressing force is larger than the pressure of CNG (which decreases due to the passage resistance) to penetrate from the part S in FIG. 2 and pass between the liner 2 and the elastic sealing material 18 as shown by the arrow. In particular, since a part of the elastic sealing material 18 pushed up by the annular ridge 28 of the air pressure valve 26 is strongly pressed against the liner 2, the pressing force of the part is particularly large. Therefore,
The passage of CNG can be stopped at the pressing portion between the liner 2 and the elastic sealing material 18, so that leakage of CNG from the base 6 can be blocked.

The left base 7 does not need to penetrate the liner 2 since the joint is not connected to the joint. Therefore, the hermetic seal is perfect, and the sealing property between the liner 2 and the base 7 does not matter, so that the details of the structure are omitted.

The FRP reinforcement layer 8 includes, for example, a helical winding reinforcement layer in which carbon fibers are wound helically in substantially an axial direction so as to cover both end walls 4, and a carbon fiber around the peripheral wall 3. And a hoop-wound reinforcing layer wound in a hoop direction, and the carbon fibers are impregnated and fixed with an epoxy resin.

The pressure vessel 1 is manufactured through the following steps. As shown in FIGS. 3 and 4, an air pressure valve 26 is attached to the liner-facing surface 12 a of the flange portion 12 of the base body 10, and both are set in a mold (not shown) in this state to set the elastic sealing material 18. These are installed by molding,
Assemble 6,18.

As shown in FIG. 5, the female plug 20 is screwed so that a polyethylene resin powder, which will be described later, does not adhere to the female screw portion 17 of the boss portion 11 or flow to the outside. An auxiliary plug 20a made of fluororesin is attached to the tip of the plug 20 by screws.
Prevents the polyethylene resin powder from entering the one end opening of the ventilation hole 19. The male screw 1 of the boss 11
The base body 10 is held by the holding shaft 21 by screwing the female screw 22 at the tip of the holding shaft 21 into the screw 4. Similarly, the other base 7 is held by a holding shaft (not shown). The base body 10 and the base 7 thus held (hereinafter, referred to as a base).
The cap 7 is omitted. ) Is set at a predetermined position of the mold 23, and the mold 23 is heated to about 270 ° C. by a furnace (not shown). While the mold 23 is being rotated, polyethylene resin powder is put into the inside thereof, and this state is maintained for, for example, 23 minutes.
The mold 23 has a projection 23 for forming a recess 29 for receiving the ring plate 13 in the liner 2.
a is provided.

At this time, the base body 10 is disposed slightly shifted toward the center of the mold 23 so that the flange portion 12 is separated from the inner surface of the liner 2. Then, by taking a sufficient distance, the end of the liner 2 is brought into contact with the boss 1.
This has the effect of helping to ensure that the outer periphery of the first is formed. Further, due to the separation, a part of the polyethylene resin powder adheres to the outer periphery of the boss portion 11 and the holding shaft 21 and the surface of the flange portion 12 (elastic sealing material 18) and is melted, thereby forming an excess portion 24.

The polyethylene resin of the liner 2 and the surplus portion 24 is cooled from the temperature at the time of rotational molding (about 270 ° C.) to a temperature that is preferably about 20 to 30 ° C. higher than the melting point (for example, cooled to about 190 ° C.). D) While still in the molten state, as shown in FIG. 6, the holding shaft 21 is pulled, and the base body 10 is displaced in the outward direction of the mold 23,
The elastic sealing material 18 of the flange portion 12 is brought into contact with the inner surface of the liner 2 and adhered. This displacement causes the boss 11
The surplus portion 24 on the outer periphery of the holding shaft 21 is wrung and collected, and is absorbed as a part of the liner 2 together with the surplus portion 24 of the flange portion 12. In order to restrict the thickness of the liner 2 sandwiched between the mold 23 and the flange portion 12 to a predetermined value, it is preferable to provide a screw mechanism for adjustment so that the holding shaft 21 is not displaced more than necessary. .

After the polyethylene resin of the liner 2 is sufficiently cooled and hardened, as shown in FIG.
The liner 2 with 0 is removed from the mold, and the plug 20 and the holding shaft 21 are removed. The ring plate 13 is attached to the boss 1
1 and fitted into a concave portion 29 formed on the outer surface of the liner 2 and the lock nut 15 is screwed into the male screw portion 14 of the boss portion 11, and as shown in FIG. 13 and the flange portion 12 through the liner 2
Firmly and mechanically. In order to prevent stress relaxation during tightening, as shown in part C of FIG.
The 0 and the ring plate 13 are provided with stopper portions that come into contact with each other.

When the FRP reinforcing layer 8 is formed by helically winding and hoop winding carbon fibers around the entire outer periphery of the liner 2 and impregnating and fixing the same with an epoxy resin, the pressure vessel 1 is completed.

According to the pressure vessel 1 of the present embodiment, the flange portion 12 having a sufficient area
In addition to the above, the above-mentioned functions (1), (2), and (3) are performed, so that the reliability of the hermetic seal between the liner 2 and the base 6 is improved as compared with the conventional example in which only the adhesion between the liner and the base is performed. Can be enhanced.

Also, unlike the conventional example, there is an advantage that it is not necessary to cut the end of the liner 2 to be tightened, and therefore no cutting waste enters the liner 2, so that a troublesome removal operation is also required. Absent.

Further, according to the method of manufacturing the pressure vessel 1 of the present embodiment, when the liner 2 is rotationally molded,
Is separated from the inner surface of the liner 2, and when the polyethylene resin of the liner 2 is cooled to some extent and is still in a molten state, the flange portion 12 is brought into contact with the inner surface of the liner 2 for the first time. The temperature difference in the subsequent cooling becomes smaller than before. For this reason, the difference in material shrinkage from the flange portion 12 due to cooling, which occurs in the portion of the liner 2 attached to the flange portion 12, becomes smaller than before, and the residual strain and residual stress also become smaller. For this reason, when the pressure vessel 1 is used (especially at a low temperature), even if the temperature difference due to the change of the air temperature is repeatedly applied, the liner 2 is not used.
There is no possibility that cracks will occur in the same part, and an airtight seal can be maintained.

The present invention is not limited to the above-described embodiment, but can be embodied with appropriate modifications without departing from the spirit of the invention, for example, as described below. (1) Although the ring plate 13 and the lock nut 15 are separate bodies in the above-described embodiment, they may be formed separately and then joined to be integrated, or may be integrally formed from the beginning. (2) Forming the liner 2 by blow molding. (3) Implement as a pressure vessel for filling various pressurized substances other than CNG. For example, in the case of LNG, the internal pressure is 50
kg / cm ² , and in the case of LPG, the internal pressure is 35 k
Since it is about g / cm ² , the strength design becomes easier and easier to implement than in the above embodiment.

[0034]

As described above in detail, according to the pressure vessel of the present invention, the excellent effect that the reliability of the hermetic seal between the synthetic resin liner and the metal base can be improved. Play.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pressure vessel according to an embodiment of the present invention with a middle part omitted.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a perspective view showing a base body and an air pressure valve of the pressure vessel.

FIG. 4 is a sectional view showing a base body and a pneumatic valve of the pressure vessel.

FIG. 5 is a cross-sectional view of a main part showing rotation molding of a liner of the pressure vessel.

FIG. 6 is a sectional view of a main part showing displacement of the base body after the rotation molding.

FIG. 7 is a sectional view of a main part when a ring plate and a lock nut are applied to the base body.

FIG. 8 is a sectional view of a main part showing a state where the lock nut is tightened.

FIG. 9 is a cross-sectional view showing a conventional pressure vessel with a middle part omitted.

FIG. 10 is a cross-sectional view of a main part showing rotation molding of the liner of the pressure vessel.

FIG. 11 is a sectional view taken along line XI-XI in FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 pressure vessel 2 liner 6 base 10 base body 11 boss part 12 flange part 12a liner facing surface 13 ring plate 15 lock nut 18 elastic seal material 18a inner peripheral edge 18b outer peripheral edge 19 vent hole 26 atmospheric pressure valve 27 annular groove 28 annular protrusion Article

Claims (5)

[Claims] 1. A liner made of synthetic resin, a base body including a cylindrical boss portion and a flange portion protruding from an outer periphery of the boss portion, wherein the boss portion penetrates the liner and the flange is formed. A pressure vessel in which the base body is disposed so that a portion is located on the inner surface side of the liner, wherein one end of the flange portion communicates with the inside of the liner, and the other end faces a liner-facing surface of the flange portion. An air hole to be opened is formed, and a ring-shaped air pressure valve is attached to the liner-facing surface of the flange portion so as to cover the other end opening of the air hole, and the air pressure valve is provided to the liner-facing surface of the flange portion. A pressure vessel, wherein an annular sealing material is provided so as to cover the sealing material, and the elastic sealing material is brought into contact with an inner surface of the liner. 2. The pressure vessel according to claim 1, wherein an annular groove is provided on a surface of the air pressure valve facing the flange. 3. The pressure vessel according to claim 1, wherein an annular ridge is provided on a surface of the air pressure valve facing the elastic sealing material. 4. An inner and outer periphery of said elastic sealing material is provided one size larger than said air pressure valve, and an inner and outer peripheral edge of said elastic sealing material protruding from said air pressure valve is joined to a liner facing surface of said flange portion. 4. The pressure vessel according to 2, 3 or 4. 5. A ring plate which is inserted around the outer periphery of the boss portion and abuts against the outer surface of the liner, and the ring plate is fastened to the flange portion via the liner. Pressure vessel.