WO2019168078A1

WO2019168078A1 - Pressure accumulator and method for manufacturing pressure accumulator

Info

Publication number: WO2019168078A1
Application number: PCT/JP2019/007716
Authority: WO
Inventors: 浩平 ▲高▼坂; 洋流和田; 隆史細矢
Original assignee: 株式会社日本製鋼所
Priority date: 2018-02-28
Filing date: 2019-02-27
Publication date: 2019-09-06
Also published as: JP2019148325A

Abstract

Provided is a pressure accumulator having excellent pressure resistance. The pressure accumulator has a cylindrical container body, and a reinforcing cylinder disposed on the outer circumferential side of the container body, the reinforcing cylinder comprising fiber reinforced plastic. The container body is such that when the cylindrical container body is cooled, the cured reinforcing cylinder can be disposed on the outer circumferential side of the container body, and the reinforcing cylinder can be fitted to the outer circumferential side of the container body by restoring the temperature of the container body.

Description

Accumulator and method of manufacturing accumulator

This invention relates to a pressure accumulator capable of accumulating gas at a high pressure and a method for manufacturing the pressure accumulator.

High-pressure hydrogen containers used for hydrogen stations and the like include type 1 (metal container), type 2 (metal liner hoop wrap type composite pressure vessel), type 3 (metal liner full wrap type composite pressure vessel) and type 4 (nonmetal liner). Full-wrap type composite pressure vessels) are known.

With the increase in hydrogen stations for FCVs (fuel cell vehicles), hydrogen accumulators capable of storing 100 MPa class high-pressure hydrogen are required.
In Type 1, high fatigue strength can be obtained by thickening the steel, but the weight is excessive.
In Type 3, since CFRP (carbon fiber reinforced plastic) is constructed by helical winding, the cost increases. Moreover, the helical winding of the head is not easy, and the tension of the helical winding cannot be secured. In addition, self-tightening is performed to eliminate the gap between the aluminum alloy and CFRP, but the variation due to the position of the residual stress due to self-tightening is large, which affects the variation in the fatigue test results. In addition, the strength of the neck may decrease, and the destruction position cannot be guaranteed (it is not known whether it is the trunk or the head).
Type 4 is lighter than Type 3 but difficult to helically wind like Type 3. Moreover, there is a concern about hydrogen leakage between the metal of the boss portion and the resin. Also, be careful of buckling due to high thermal insulation.
Type 2 is made of steel and FRP (fiber reinforced plastic), and in addition to being reduced in weight, it is expected to reduce costs because CFRP is constructed by hoop winding. A type 2 pressure accumulator is used as one of the hydrogen pressure accumulators for storing high-pressure hydrogen.

Type 2 pressure accumulators consist of a steel liner and hoop-wrapped FRP.
The type 2 pressure accumulator is a composite container of hoop wraps. As a container construction method, (C) FRP is generally filament wound on the inner steel.
In the type 2 container, since the fiber is only the circumference (hoop), the liner shares the axial load generated by the internal pressure.
According to ASME CC2579 (see Non-Patent Document 1), the type 2 pressure accumulator was constructed and coated in the circumferential direction with a carbon fiber reinforced plastic (CFRP) or a glass fiber reinforced plastic (GFRP) on the straight body of a steel liner. A hydrogen pressure accumulator having a liner outer diameter of 1.52 m or less and a CFRP thickness of 6 mm or more.

For the steel liner, Cr—Mo steel is generally used.
Patent Document 1 discloses an FRP container for high-pressure hydrogen storage in which the outer periphery of a liner made of Cr—Mo steel is reinforced with FRP. Patent Document 2 discloses a full-wrap aluminum liner composite container.
The steel liner that shares the load is stronger as a liner than the type 3 container that uses an aluminum liner that does not share the load, and the amount of expensive FRP used can be reduced by that amount, which contributes to reduction of hydrogen station construction costs. It is expected. Regarding the high-pressure hydrogen hoop wrap type compound pressure vessel, there is only an overseas technical standard as Non-Patent Document 1.

When constructing FRP, filament winding (FW) is a method in which fibers are wound around a steel liner in a circumferential direction at regular and constant loads and intervals, and the resin is cured by heating from inside and outside in the furnace. The method by is used.
In the above method, as shown in FIG. 8, CFRP (carbon fiber reinforced plastic) is heated together with the liner in the furnace, and the CFRP is cured in a state where the steel liner is expanded.

Japanese Unexamined Patent Publication No. 2009-293799 Japanese Unexamined Patent Publication No. 2007-154927 Japanese Unexamined Patent Publication No. 2011-073191

However, with the method of winding CFRP around a steel liner by filament winding, it is difficult to cure CFRP having sufficient strength without gaps.
That is, in filament winding, a resin liner is impregnated with a reinforcing fiber such as carbon fiber, filament winding is performed on a steel liner, and then heated to cure the resin. After the curing is completed, the steel liner shrinks when cooled to room temperature, but the layer containing carbon fiber and resin does not substantially shrink because the coefficient of thermal expansion is smaller than that of the liner, and at the time of heat curing. It cools and hardens with the inner diameter of For this reason, as shown in FIG. 8, a gap will be generated between the steel liner and the CFRP.
Furthermore, since the resin generates heat during the heat curing, the temperature of the liner further increases, and the gap may become large.
As mentioned above, in order to obtain sufficient strength for a type 2 accumulator as a composite container, it is indispensable to construct CFRP with as little gap as possible, but in CFRP construction by filament winding molding (FW molding), there is a difference in thermal expansion coefficient. It is not possible to suppress the gap caused by.

The expected gap can be calculated by {(liner outer surface maximum temperature−room temperature) × liner thermal expansion coefficient}.
In addition, in patent document 1, it is not touched on the construction method which does not generate | occur | produce a clearance gap between FRP and a steel liner most important for ensuring safety | security. Further, in Patent Document 3, means for securing the adhesive strength between metal and CFRP is ensured and effective for eliminating the gap, but the target is a prepreg and not a resin impregnation method. Further, the adhesive strength alone cannot withstand high pressure hydrogen of 40 MPa or more, and it cannot be solved unless the gap can be physically reduced.

The present invention has been made against the background of the above circumstances, and arranges a cylindrical container body and a reinforcing cylinder disposed on the outer peripheral side of the container body in a state in which the outer surface and the inner surface thereof are in contact with each other. An object of the present invention is to provide a pressure accumulator and a method for manufacturing the pressure accumulator.

That is, among the pressure accumulators of the present invention, the first form has a cylindrical container body and a reinforcing cylinder disposed on the outer peripheral side of the container body, and the reinforcing cylinder is made of fiber reinforced plastic. In addition, the container body is disposed such that an outer surface thereof is in contact with an inner surface of the reinforcing cylindrical body.

In another aspect of the invention of the pressure accumulator, in the invention of the above aspect, the container body exerts a compressive stress that is tightened to the outer peripheral side.

In another aspect of the invention of the pressure accumulator, in the invention of the above-mentioned form, the fiber reinforced plastic includes a thermosetting plastic.

According to another aspect of the invention of the pressure accumulator, in the aspect of the invention, the container body is disposed such that an outer surface thereof is in close contact with an inner surface of the reinforcing cylinder.

In another aspect of the invention of the pressure accumulator, in the invention of the above aspect, the reinforcing cylinder has an average interlayer shear strength of the inner surface larger than an average interlayer shear strength of the outer surface.

In another form of the pressure accumulator, in the above-mentioned form of the invention, the container body has a stress intensity that linearly increases as the pressure increases on the inner surface of the container body within a predetermined internal pressure range. Yes.

In another aspect of the invention of the pressure accumulator, in the aspect of the invention, the internal pressure range is 0 to 150 MPa.

In the invention of the other form of the pressure accumulator, the pressure is accumulated in the internal pressure range of 100 MPa or less in the invention of the above form.

Of the invention of the pressure accumulator manufacturing method of the present invention, the first aspect is that the cylindrical container body is cooled, the cured reinforcing cylinder is disposed on the outer peripheral side of the container body, and the temperature of the container body is restored. The reinforcing cylinder is fitted to the outer peripheral side of the container body.

In another aspect of the invention of the method of manufacturing a pressure accumulator, in the invention of the above aspect, the container main body is in contact with the inner surface of the reinforcing cylindrical body in a state where the temperature is restored.

In another form of the pressure accumulator, the interference ratio in the container main body before the cooling is −1.07 to 2.67 at 1000 fractions in the form of the invention.

In another aspect of the invention of the pressure accumulator, in the aspect of the invention, in the cooling, the container body is cooled to a temperature lower than room temperature.

In another form of the invention of the pressure accumulator, the container body is cooled to −190 ° C. to −160 ° C. in the form of the invention.

According to the present invention, the cylindrical container main body and the reinforcing cylindrical body disposed on the outer peripheral side of the container main body can be brought into a state where the outer surface of the container main body and the inner surface of the reinforcing cylindrical body are in contact with each other. The effect excellent in the performance as a container is acquired.

FIG. 1 is a diagram showing a pressure accumulator manufacturing method and a pressure accumulator according to an embodiment of the present invention. FIG. 2 is a view for explaining a construction example in the fitting of the container body to the reinforcing cylinder. FIG. 3 a is a front cross-sectional view showing a state where the container body is fitted to the reinforcing cylinder. FIG. 3b is a cross-sectional view taken along the line II of the front cross-sectional view showing a state in which the container main body is fitted to the reinforcing cylinder. FIG. 4a is a diagram showing a water pressure test result of the pressure accumulator obtained by filament winding molding. FIG. 4 b is a diagram illustrating a water pressure test result of the pressure accumulator obtained by fitting in the example. FIG. 5a is a graph showing the interlaminar shear strength of CFRP obtained by the filament winding molding method in the examples. FIG. 5b is a graph showing the interlaminar shear strength of fully cured CFRP in the examples. FIG. 6 is a diagram showing the stress intensity of the liner inner surface of the container body when the inner pressure is applied to the pressure accumulator by changing the interference in the embodiment. FIG. 7 is a diagram showing the strain in the fiber direction on the inner surface of the CFRP when the inner pressure is applied to the pressure accumulator by changing the interference in the embodiment. FIG. 8 is a diagram for explaining a filament winding molding method.

Hereinafter, an embodiment of the present invention will be described.
First, a reinforcing cylinder is formed from a predetermined fiber reinforced plastic. The fiber reinforced plastic preferably includes a thermosetting plastic.
The type of fiber and the type of thermosetting plastic are not particularly limited, and an appropriate material can be selected for the present invention. In this embodiment, examples of the fiber include glass fiber and carbon fiber, and carbon fiber is preferably used. Moreover, as a thermosetting plastic, an epoxy resin, a phenol resin, a urea resin, a melamine resin, a polyurethane, etc. can be used. Although it is not limited to specific resin as this invention, an epoxy resin or a phenol resin is preferable from a heat resistant viewpoint.

The hardening method in the reinforcement cylinder 2 is not specifically limited, It can shape | mold by a normal method.
For example, the outer surface of a cylindrical mold (mandrel) is made by attaching a thermosetting plastic powder to a fiber base impregnated with a thermosetting plastic, or winding a thermosetting plastic containing fibers by the FW method. And heating at a predetermined temperature in a heating furnace and pressurizing as necessary to thermoset the thermosetting plastic and mold it. The heating temperature can be determined according to the characteristics of the thermosetting plastic. The reinforcing cylinder 2 is obtained by removing the core from the thermosetting plastic completely cured by this heating (withdrawing the mandrel). A mold or the like may be used for heating and pressurization.

As shown in FIG. 1, a cylindrical container body 1 is fitted on the inner peripheral side of the cured reinforcing cylinder 2.
In the fitting, the container main body 1 is cooled, and the container main body 1 </ b> A having a reduced cylinder diameter is inserted into the reinforcing cylinder 2. At this time, the cylinder diameter of the container main body 1 </ b> A is reduced by cooling, and the cooled container main body 1 </ b> A can be easily fitted into the cured reinforcing cylinder 2. After the fitting, the container body 1A is expanded in diameter by returning to normal temperature, and the outer surface of the expanded container body 1B is in contact with, preferably in close contact with, and more preferably, the interference by the inner surface of the reinforcing cylinder 2. Press contact with the reinforcing cylinder 2.
Here, the pressure contact indicates a state in which a residual stress is further applied in a close contact state.
Therefore, in this construction, it is preferable to manufacture the container main body 1 and the reinforcing cylinder 2 separately so that the outer diameter of the container main body 1 is larger than the inner diameter of the reinforcing cylinder 2 at room temperature. That is, it is preferable that the interference (ratio) is positive at room temperature. In the present invention, the relationship between the inner diameter of the cured reinforcing cylinder 2 and the outer diameter of the container body 1 is such that the container body 1 has an interference ratio of −1.07 to 2.67 at 1000 fractions. It is preferable to have. The interference is represented by (outer surface diameter of container body−inner surface diameter of reinforcing cylinder), and the interference ratio is expressed by (interference / outer surface diameter of container × 1000).

In cooling the container body 1, the cooling temperature can be determined in consideration of the outer diameter of the container body 1 and the inner diameter of the hardened reinforcing cylinder 2. In cooling the container body 1, the container body 1 is cooled to a temperature below room temperature. For example, the cooling temperature is preferably in the range of -190 ° C to -160 ° C. By setting the cooling temperature to −160 ° C. or lower, the container body can be sufficiently reduced in diameter. On the other hand, if the temperature is lower than −190 ° C., it takes time for cooling and the productivity is poor, so it is preferable to cool to the above temperature range. However, in the present invention, the cooling temperature is not limited to a specific temperature, and an appropriate temperature can be selected as long as the fitting can be easily performed.

The method of fitting the completely cured reinforcing cylinder 2 to the container body 1 is not particularly limited, and can be performed by an appropriate method.
An example of an insertion process is demonstrated based on FIG.
The container main body installation cylinder 10 has an installation base 11 at the inner center lower portion, and is installed in a state where the container main body 1 is built on the installation base 11. On the inner surface of the container main body installation cylinder 10, a plurality of gas injection units 12 having injection ports for injecting gas toward the inner peripheral side are installed along the circumferential direction and at a plurality of height positions. A container body fixing tool can be arranged on the upper side of the container body installation cylinder 10, and when the container body 1 is installed, the container body fixing tool holds and fixes the container body 1 at the upper side on the lower side. Can do. A temperature data logger 13 that can automatically measure the temperature at regular intervals is attached to the outer surface of the mirror part of the container body 1, and the temperature change of the container body 1 can be recorded, for example, at an interval of 1 minute.

Further, in the vicinity of the container main body installation cylinder 10, there is a holding base 20 for standing and holding the completely hardened reinforcing cylinder 2, and a suspension for hanging the reinforcing cylinder 2 installed on the holding base 20. The tool 21 is located above the installation position of the reinforcing cylinder 2, and the hanging tool 21 and the reinforcing cylinder 2 can be connected via the connecting tool 22.

Next, construction contents will be described. In addition, the container main body 1 is installed in the container main body installation cylinder 10, the reinforcement cylinder 2 is hold | maintained at the holding stand 20, and the reinforcement cylinder 2 shall be connected with the hanger 21. As shown in FIG.
In the container main body installation cylinder 10, initially, nitrogen gas is irradiated from the gas injection unit 12 toward the container main body 1 to remove the gas on the container main body 1. Thereafter, liquid nitrogen is injected from the gas injection unit 12 to cool the container body 1. The temperature of the container body 1 can be measured with a temperature data logger. After confirming that the container main body 1 has reached, for example, −160 ° C. or less, the reinforcing cylinder 2 is fitted to the container main body 1 by lifting it from the side where the temperature data logger 13 is not attached.
Then, in the container main body installation cylinder 10, the container main body 1 and the reinforcement cylinder 2 are returned to normal temperature in nitrogen atmosphere.
The container main body 1 and the reinforcing cylinder 2 are in a state where the outer surface of the container main body 1 is in contact with the inner surface of the reinforcing cylinder 2. Depending on the value of the interference, the outer surface of the container body 1 and the inner surface of the reinforcing cylinder 2 are brought into close contact with each other, and the container body 1 is pressed against the reinforcing cylinder 2 to be tightened to the outer surface of the container body 1 by the reinforcing cylinder 2. Such compressive stress is generated.

3a and 3b show a state in which the container main body 1B is fitted to the reinforcing cylinder 2.

Lids

1C and 1C are attached to both ends of the container main body 1B so that the inside of the container main body 1B can be sealed. The outer surface of the container main body 1 and the inner surface of the reinforcing cylindrical body 2 are fitted together with almost no gap. More preferably, there is no gap at all, and the outer surface of the container body 1 is in close contact with the inner surface of the reinforcing cylinder 2.
As a method for confirming that there is no gap (close contact), a strain gauge is attached to both the container body 1B and the reinforcing cylinder 2, and it is examined whether the strain has linearity and reproducibility at low pressure. If the strain of the CFRP and the container body rises linearly as the water pressure increases from the attached strain gauge, it can be evaluated that the outer surface of the container body 1 is in close contact with the inner surface of the reinforcing cylinder 2.
For example, a strain gauge is attached to the outer surface of the specimen obtained by fitting, and water pressure is applied to the inside of the specimen placed in a vertical position. Data from strain gauges can be collected and the presence or absence of linearity and reproducibility can be confirmed for each measurement position.

The obtained pressure accumulator is capable of accumulating high-pressure gas. For example, gas such as hydrogen can be favorably accumulated up to 100 MPa.

A fiber substrate containing a thermosetting plastic is wrapped around the outer surface of a steel liner, heated in a heating furnace at a temperature of 85 ° C. for 10 hours, cured, FW molded, (a) Filament winding molded (FW A pressure accumulator was obtained.
The heating temperature needs to take into account the thermal expansion of the steel liner and cannot be raised to a temperature at which the thermosetting plastic is completely cured.

Further, a fiber base material containing a thermosetting plastic was wound around the outer surface of a cylindrical mold (mandrel), and was cured by heating at a temperature of 130 ° C. for 5 hours in a heating furnace. The reinforcing cylinder 2 was FW-molded by removing the core from the thermosetting plastic completely cured by heating (withdrawing the mandrel). By fitting the obtained reinforcing cylinder 2 to a steel liner, a pressure accumulator by fitting (b) of this embodiment was obtained.

Next, with respect to (a) the accumulator obtained by filament winding molding (FW molding) and (b) the accumulator obtained by fitting of this embodiment, a water pressure test was carried out in a vertically placed state. The obtained strain responsiveness was compared in FIGS. 4a and 4b. The pressure range of the water pressure test was 0 to 150 MPa for FW molding, 0 to 60 MPa for fitting, and the number of cycles was 3. In addition, the thickness of CFRP by FW molding and CFRP which is a reinforcing cylinder was set to 10 mm (the same applies hereinafter).
In the test, a steel liner for type 2 having an outer diameter of about 374 mm, a thickness of 29 mm, and a length of about 2700 mm was used.
FIGS. 4a and 4b show both measured values and analytical values of the strain. The analytical values are the strain values in the axial direction and circumferential direction of the outer surface of the CFRP. FEM analysis was performed in increments of 10 MPa each in the range of 0 to 50 MPa.
On the other hand, the measured value of strain was obtained by attaching a biaxial strain gauge to both ends and the center of the CFRP, and collecting and collecting the strain value at the time of pressure increase / decrease.

As shown in FIG. 4a, in the accumulator obtained by FW molding, it is understood that the rise of strain is poor when the internal pressure is applied, and a gap of about 0.2 mm is generated between the liner and the CFRP.
On the other hand, as shown in FIG. 4b, in the accumulator obtained by fitting, the strain from the low pressure has linearity, and the analysis value shows a good agreement. Therefore, it turns out that both a container main body and a reinforcement cylinder fulfill | perform load sharing.

In addition, an interlaminar shear strength test was performed on CFRP obtained by wrapping around a liner by FW molding and CFRP completely cured from the premise of fitting, and the results were compared. The test results are shown in FIGS. 5a and 5b.
The CFRP obtained by wrapping around the liner by FW molding and the end portion of CFRP completely cured from the premise of fitting are cut into small pieces, and 4 × 8 from the inner surface and outer surface of the obtained CFRP. A test piece of x24 mm was collected. The numbers of the bar graphs in FIGS. 5a and 5b indicate the number of test pieces.
The test was conducted according to ASTM D 2344, and the test environment was temperature: 23 ± 2 ° C. and relative humidity: (50 ± 5)% RH. The test speed was 1 mm / min, the indenter tip was R3, the support tip was R1.5, and the support span was 16 mm.

Comparing the test results, as shown in FIGS. 5a and 5b, the fully cured CFRP clearly has a larger interlayer shear strength on the inner surface side. From the above, fitting is extremely effective as a construction method of a pressure accumulator that can express the characteristics of the composite container and has no gap.
In addition, the type 2 pressure accumulator subjected to CFRP by fitting has a positive interference ratio (interference) and contributes to an increase in life.

FIG. 6 shows an FEM analysis of the stress intensity on the inner surface of the liner when an internal pressure is applied in the range of 0 to 300 MPa to a pressure accumulator having an interference of −0.3 to +1.0 mm (analysis software: Ansys). ).
The liner has an outer diameter of about 374 mm, a thickness of 29 mm, and an elastic-plastic body (two-line approximation), and the CFRP tube has a thickness of 10 mm and a fiber content of 60%.
The stress intensity on the inner surface of the liner decreases as the interference increases.
That is, even if the same internal pressure is applied to the liner, the acting stress is reduced and the life is increased.
Here, it is known that there is a correlation between the fatigue limit (σw0) and the tensile strength (σB) of the metal material, and σw0 = 0.5 × σB. (See Non-Patent Document 2)
Since the liner material is SCM435 TKB (TS = σB = 770 MPa), the fatigue limit σw0 is 770 × 0.5 = 385, which is slightly less than 400 MPa.
The above value (400 MPa) is approximately equal to the stress intensity of the liner inner surface when the interference is 1 mm (corresponding to an interference ratio of 2.67) and an internal pressure of 100 MPa is applied.
Therefore, when the interference ratio exceeds 2.67, it is considered that the liner does not undergo fatigue failure when the hydrogen pressure accumulator is used.

On the other hand, FIG. 7 shows an FEM analysis of the strain in the fiber direction on the inner surface of the CFRP when an internal pressure is applied in the range of 0 to 300 MPa to an accumulator having an interference of −0.3 to +1.0 mm (analysis software). : Ansys).
Here, the carbon fiber (T710SC) has a breaking strain of 1.7%, and according to ASME KD-1310, the upper limit of the strain at which the CFRP does not break is 0.4 when operating with respect to the breaking strain. In the case of a pressure test, it must be considered by multiplying by 0.67 (see Non-Patent Document 3).

Assuming that the operating pressure is 100 MPa and the pressure test is 150 MPa, the upper limits of the strain at which the CFRP does not break during operation and the pressure test are 0.68 and 1.12.
If the CFRP does not reach the upper limit of strain during operation, that is, if the interference is 1 mm or less (interference ratio is 2.67 or less), the CFRP will not fatigue. (Refer to FIG. 6 of Non-Patent Document 5 and Non-Patent Document 5)
On the other hand, if the interference exceeds 1 mm (interference ratio exceeds 2.67), the CFRP breaks during operation, and the pressure accumulator loses its characteristics as a composite container.
From the above, the upper limit value of the interference ratio is 2.67.
On the other hand, the lower limit of the interference ratio is qualitatively a value at which the liner does not come into contact with CFRP even when the operating pressure is reached, and the function as a composite container is not exhibited.
This is an interference that does not deviate up to 100 MPa from the curve obtained with No CFRP (liner only) in FIG. 7, and the value is −0.4 mm, which corresponds to an interference ratio of −1.07.

As described above, the present invention has been described based on the above embodiment, but the present invention is not limited to the content of the above embodiment, and is appropriate for the present embodiment without departing from the scope of the present invention. It can be changed.

According to the present invention, the cylindrical container body and the reinforcing cylinder disposed on the outer peripheral side of the container body can be brought into a state where the outer surface of the container body and the inner surface of the reinforcing cylinder are in contact with each other. An excellent pressure accumulation container and a method for producing the pressure accumulation container can be provided.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application (Japanese Patent Application No. 2018-35161) filed on Feb. 28, 2018, the contents of which are incorporated herein by reference.

1, 1A, 1B Container body 1C Lid 2 Reinforcing cylinder

Claims

A cylindrical container body, and a reinforcing cylinder disposed on the outer peripheral side of the container body,
The reinforcing cylinder includes fiber reinforced plastic;
The container main body is an accumulator in which an outer surface is disposed in contact with an inner surface of the reinforcing cylindrical body.
The pressure accumulator according to claim 1, wherein the reinforcing cylindrical body exerts a compressive stress that is tightened to an outer peripheral side of the container main body.
The pressure accumulator according to claim 1 or 2, wherein the fiber reinforced plastic includes a thermosetting plastic.
The pressure accumulator according to any one of claims 1 to 3, wherein the container body is disposed such that an outer surface thereof is in close contact with an inner surface of the reinforcing cylindrical body.
The pressure accumulator according to any one of claims 1 to 4, wherein the reinforcing cylinder has an average interlayer shear strength on the inner surface larger than an average interlayer shear strength on the outer surface.
The accumulator according to any one of claims 1 to 5, wherein the container body has a stress intensity that linearly increases with an increase in pressure on the inner surface of the container body within a predetermined internal pressure range. .
The pressure accumulator according to claim 6, wherein the range of the internal pressure is 0 to 150 MPa.
The pressure accumulator according to any one of claims 1 to 7, wherein pressure is accumulated in an internal pressure range of 100 MPa or less.
A pressure accumulator that cools a cylindrical container body, places a cured reinforcing cylinder on the outer peripheral side of the container main body, and fits the reinforcing cylindrical body on the outer peripheral side of the container main body by returning the temperature of the container main body. Production method.
The method for manufacturing a pressure accumulator according to claim 9, wherein the container body is in contact with the inner surface of the reinforcing cylindrical body in a state where the temperature is restored.
The method for manufacturing a pressure accumulator according to claim 9 or 10, wherein an interference ratio in the container main body before the cooling is from -1.07 to 2.67 at 1000 minutes.
The method for manufacturing a pressure accumulator according to any one of claims 9 to 11, wherein in the cooling, the container body is cooled to a temperature lower than room temperature.
The method for manufacturing a pressure accumulator according to any one of claims 9 to 12, wherein the container body is cooled to -190 ° C to -160 ° C.