Composite Pressure Vessel

Abstract

The present invention relates to a method for manufacturing and pressure testing composite pressure vessels and apparatus embodying this method.

Description

[Technical Field]

[0001] The present invention relates to a method for pressure testing composite pressure vessels used as compressed natural gas (CNG) tanks, compressed hydrogen gas (CHG) tanks, liquefied petroleum gas (LPG) tanks, etc. In particular, the present invention relates to a method for manufacturing composite pressure vessels and, more particularly, to an apparatus for manufacturing and testing composite pressure vessels. [Background technology]

[0002] The methods currently used to manufacture and test composite pressure vessels are very tedious, time consuming and labor intensive.

[0003] A known solution for testing the pressure resistance of a composite pressure vessel consists of a hydrostatic test, which requires the injection of water into the composite pressure vessel. Unfortunately, due to physical and chemical interactions between the surfaces of the internal cavity of the composite pressure vessel and the water, some moisture may remain after the test, which may lead to contamination of the stored gas, necessitating a time-consuming drying step by injecting gas into the composite pressure vessel at ambient temperature and atmospheric pressure. Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a method for pressure testing composite pressure vessels, typically used as compressed natural gas (CNG), compressed hydrogen gas (CHG), and liquefied petroleum gas (LPG) tanks, that overcomes the aforementioned problems previously present in the industry. More specifically, the present disclosure provides a method for fabricating composite pressure vessels that does not require a lot of time. Finally, the present disclosure provides an apparatus for fabricating and testing composite pressure vessels.

[0005] In particular, a first object of the present disclosure is to provide a method for pressure testing a composite pressure vessel that is not cumbersome, time-consuming, or labor-intensive.

[0006] A second object of the present disclosure is to provide a method for manufacturing a composite pressure vessel that reduces the manufacturing time.

[0007] A third object of the present disclosure is to provide an apparatus for manufacturing and testing composite pressure vessels.

[0008] A fourth object of the present invention is to provide a pressure test apparatus for a composite pressure vessel. [Means for solving the problem]

[0009] A first object of the present invention is to provide a method for pressure testing a composite pressure vessel that achieves these objects. The method for pressure testing a composite pressure vessel according to the present invention comprises: a providing a composite pressure vessel with at least one opening, preferably a single opening, for injecting a liquid; b. injecting a liquid into the composite pressure vessel through at least one opening to reach a threshold pressure; c. measuring the external volume change of the composite pressure vessel; d. draining the liquid from the composite pressure vessel through at least one opening; e. drying the inner cavity of the composite pressure vessel using a dry gas; Including, The step of drying the interior cavity of the composite pressure vessel is carried out at a pressure inside the composite pressure vessel that is lower than the external pressure.

[0010] The use of a pressure inside the composite pressure vessel that is lower than the external pressure can accelerate boiling and vaporization of the remaining liquid present in the composite pressure vessel after step d of draining the liquid from the composite pressure vessel, thus leading to rapid removal of said liquid. Preferably, the external pressure is atmospheric pressure.

[0011] The composite pressure vessel of the present disclosure may be a Type IV composite pressure vessel with an inner liner made of unreinforced polymer forming an internal cavity and enclosed in a fiber-reinforced polymer shell, or a Type III composite pressure vessel with a metal liner enclosed in a fiber-reinforced polymer shell, or a Type V composite pressure vessel consisting of a fiber-polymer shell. Preferably, the composite pressure vessel of the present disclosure is a Type IV composite pressure vessel with an inner liner made of unreinforced polymer forming an internal cavity and enclosed in a fiber-reinforced polymer shell.

[0012] By the expression "external pressure", the present invention intends to mean pressure applied to the outer surface of the fiber-reinforced polymer shell.

[0013] By the expression "the pressure inside the composite pressure vessel is lower than the external pressure," the present invention intends to mean that the pressure inside the composite pressure vessel is reduced relative to the surrounding atmospheric pressure in order to accelerate the evaporation of the remaining liquid. At the same time, if the composite pressure vessel is a Type III or Type IV pressure vessel, the pressure applied to the outside of the composite pressure vessel may also be reduced so that the difference between the internal and external pressures is such that the collapse of the inner liner vessel is avoided. Preferably, the pressure inside the composite pressure vessel remains higher than the external pressure. Depending on the pressure vessel's construction, a certain level of relative negative pressure inside the vessel can be achieved, and if the composite pressure vessel is a Type III or Type IV pressure vessel, it can be tolerated while avoiding the collapse of the inner liner.

[0014] The expression "internal cavity of the composite pressure vessel" is intended in the present invention to mean the cavity in which the compressed gas is stored.

[0015] The step of drying the interior cavity of the composite pressure vessel is the step of drying the inner liner of the composite pressure vessel if the composite pressure vessel is a Type III or Type IV pressure vessel.

[0016] At least one opening of the composite pressure vessel is provided with a first boss. Preferably, the composite pressure vessel is provided with a second boss, preferably located on the opposite side of the composite pressure vessel relative to the first boss. The second boss does not necessarily have to be located at the opening.

[0017] According to one embodiment, the method for pressure testing a composite pressure vessel according to the invention is such that said method comprises the step of heating the composite pressure vessel.

[0018] The step of heating the composite pressure vessel can remove any remaining liquid still present after the step of draining the liquid from the composite pressure vessel through the at least one opening. Further, the heating step can allow pressure testing at different temperatures.

[0019] The method for performing a pressure test on a composite pressure vessel according to the present invention may comprise the step of heating the liquid used to perform the pressure test. Preferably, the temperature used in the heating step, measured inside the composite pressure vessel, is higher than the boiling temperature of the liquid at the pressure used in the drying step e.

[0020] According to a preferred embodiment, a method for pressure testing a composite pressure vessel according to the present invention includes a step of heating the composite pressure vessel, including a radiant heating step, in which a heat dissipation device is introduced through at least one opening in the composite pressure vessel. Preferably, the heat dissipation device generates radiation waves within a bandwidth that maximizes heat absorption by the inner surface of the internal cavity of the composite pressure vessel. Radiation power is controlled to avoid overheating of the inner surface of the internal cavity of the composite pressure vessel.

[0021] Preferably, the step of heating the composite pressure vessel is performed during the step of drying the internal cavity of the composite pressure vessel, thereby reducing the time required to perform the method for pressure testing the composite pressure vessel.

[0022] According to a preferred embodiment, the method for performing a pressure test on a composite pressure vessel according to the present invention is such that the liquid used for performing the pressure test is a liquid whose contact angle with the surface of the internal cavity of the composite pressure vessel is larger than the contact angle of water with the surface of the internal cavity.

[0023] Liquids with a contact angle larger than that of water tend not to adhere to the surface of the internal cavity, and are therefore easily expelled by blowing gas into the COPV.

[0024] According to a preferred embodiment, the method for pressure testing a composite pressure vessel according to the invention is such that the liquid has a vaporization temperature lower than the vaporization temperature of water at atmospheric pressure.

[0025] The drying step can be accelerated under pressure conditions, preferably by using a liquid whose vaporization temperature is lower than that of water at atmospheric pressure.

[0026] According to a preferred embodiment, the method for performing a pressure test on a composite pressure vessel according to the present invention is such that the liquid used for performing the pressure test is selected from the group consisting of water, acetone, methanol, ethanol, isopropanol, butyl alcohol, and mixtures of at least two thereof.

[0027] According to a particular embodiment, the method for performing a pressure test on a composite pressure vessel according to the present invention is such that the dry gas is selected from the group consisting of N2, Ar, He, H2 or a mixture of at least two thereof.

[0028] By using an inert gas such as N2, Ar, He, H2 or a mixture of at least two thereof as the drying gas, contamination of the composite pressure vessel can be avoided, especially when storing compressed hydrogen gas (H2).

[0029] According to one precious alternative embodiment, the method for pressure testing the composite pressure vessel according to the invention is such that the dry gas is air.

[0030] The use of air as a dry gas simplifies the test method and is preferably limited to composite pressure vessels used to store compressed natural gas (CNG) or liquefied petroleum gas (LPG).

[0031] According to a preferred embodiment, the method for pressure testing the composite pressure vessel according to the invention is such that the dry gas is heated.

[0032] The use of heated dry gas speeds up the process, thereby reducing the total cycle time to perform the test.

[0033] According to a preferred embodiment, the method for pressure testing a composite pressure vessel is such that said method comprises a step of rinsing with a solvent that forms an azeotrope with the liquid injected in step a).

[0034] A second object of the present invention is to provide a method for manufacturing a composite pressure vessel. The method for manufacturing a composite pressure vessel according to the present invention includes a method for performing a pressure test on the composite pressure vessel disclosed above.

[0035] According to a preferred embodiment, the method for manufacturing a composite pressure vessel according to the present invention includes a step of fixing a valve assembly to the composite pressure vessel after a step of drying the internal cavity of the composite pressure vessel using a gas. Preferably, the step of fixing the valve assembly is performed immediately after the step of drying the internal cavity of the composite pressure vessel, which leads to reducing contamination problems of the composite pressure vessel due to external contaminants such as dust and moisture. The valve assembly is fixed to the composite pressure vessel using a first boss. Preferably, the valve assembly is fixed to the first boss by threading or by using a cam clock or a locking ring nut. The valve assembly is an OTV valve assembly.

[0036] According to a preferred embodiment, the method for manufacturing a composite pressure vessel according to the present invention comprises an additional heating step, which is a step of heating the composite pressure vessel and / or a step of heating a gas injected into the composite pressure vessel.

[0037] A third object of the present invention is to provide an apparatus for manufacturing and pressure testing a composite pressure vessel, said apparatus comprising a first chamber and a second chamber, the first chamber comprising means for pressure testing the composite pressure vessel, and the second chamber comprising means for drying the internal cavity of the composite pressure vessel.

[0038] The means for pressure testing the composite pressure vessel comprises at least a first adapter for connecting an opening of the composite pressure vessel to a circuit for injecting liquid into the interior of the composite pressure vessel, and optionally comprises means for reducing the pressure inside the first chamber, means for measuring the expansion of the length and diameter, and means for evacuating the liquid outside the composite pressure vessel.

[0039] The means for drying the internal cavity of the composite pressure vessel comprises at least a second adapter for connecting an opening of the composite pressure vessel to a circuit for injecting dry gas into the interior of the composite pressure vessel. The means for drying the internal cavity of the composite pressure vessel may also comprise means for applying a vacuum to the inside and outside of the composite pressure vessel, if necessary. Preferably, the means for drying the internal cavity, preferably the inner liner, also comprises means for heating the composite pressure vessel and means for heating the dry gas. Preferably, the means for heating is a radiant heating source.

[0040] According to a preferred embodiment, the apparatus for manufacturing and pressure testing a composite pressure vessel is such that the second chamber comprises means for fixing a valve assembly to an opening in the composite pressure vessel.

[0041] According to an alternative embodiment, an apparatus for manufacturing and pressure testing a composite pressure vessel comprises a first chamber, a second chamber, and a third chamber, the first chamber comprising means for pressure testing the composite pressure vessel, the second chamber comprising means for evacuating liquid and injecting gas, and the third chamber comprising means for drying the interior cavity of the composite pressure vessel.

[0042] A fourth object of the present invention is to provide a pressure test apparatus for a composite pressure vessel, the pressure test apparatus comprising: - a sleeve adapter assembly comprising a suction point, a suction line, and first fastening means configured to fasten the sleeve adapter assembly to a first boss of the composite pressure vessel; - a proof test adapter assembly comprising second fastening means for fastening the proof test adapter assembly to the first boss and first connecting means for connecting the composite pressure vessel to a liquid circuit; - a means for measuring deformation of the composite pressure vessel; a first chamber which is a burst containment chamber; Equipped with.

[0043] According to a preferred embodiment, the pressure test device for a composite pressure vessel is such that the first chamber comprises means for pressure testing the composite pressure vessel.

[0044] According to a preferred embodiment, the pressure test device for a composite pressure vessel comprises a second chamber provided with means for evacuating liquid and injecting gas.

[0045] According to a preferred embodiment, the pressure test apparatus for a composite pressure vessel comprises a third chamber comprising means for drying the interior cavity of the composite pressure vessel.

[0046] According to a preferred embodiment, the first fastening means for fastening the sleeve adapter assembly to the first boss comprises a plurality of openings, at least two, more preferably at least three openings.

[0047] This and other advantages of the present invention are described in more detail in the following sections.

[0048] The present disclosure will be better understood from a reading of the following examples, including the figures given as examples.

[0049] 1 to 16 are vertical cross-sectional views of a composite pressure vessel during different steps of the manufacturing and testing method according to the present invention. [Brief explanation of the drawings]

[0050] [Figure 1] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 2] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 3] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 4]1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 5] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 6] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 7] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 8] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 9] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 10] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 11] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 12] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 13] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 14] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 15] 1A-1D are vertical cross-sectional views of a composite pressure vessel during steps of a method for manufacturing a composite pressure vessel according to the present invention; [Figure 16] 1A-1D are vertical cross-sectional views of a composite pressure vessel during steps of a method for manufacturing a composite pressure vessel according to the present invention; [Figure 17]1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; [Figure 18] 1 is a detailed sketch of a sleeve adapter assembly used in the method of manufacturing and testing a composite pressure vessel according to the present invention. [Figure 19] 1A-1C are vertical cross-sectional views of a composite pressure vessel during steps of a method for performing a pressure test on the composite pressure vessel according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0051] The present invention is described with reference to specific embodiments.

[0052] FIG. 1 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. During this step, a sleeve adapter assembly (5) is secured to the first boss (4). The sleeve adapter assembly includes a suction point (52), a suction line (51), and a first fastening means (50) for securing the sleeve adapter assembly (5) to the first boss (4).

[0053] FIG. 2 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening in use. During this step, a proof test adapter assembly (8) is secured to the first boss (4). The proof test adapter assembly (8) includes second securing means (80) for securing the proof test adapter assembly (8) to the first boss (4) and first connecting means (81) for connecting the composite pressure vessel (1) to a liquid circuit.

[0054] FIG. 3 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. During this step, a proof test adapter assembly (8) is secured to the first boss (4). The proof test adapter assembly (8) includes second securing means (80) for securing the proof test adapter assembly (8) to the first boss (4) and first connecting means (81) for connecting the composite pressure vessel (1) to a liquid circuit. The composite pressure vessel (1) is filled with a liquid (9) via a proof test adapter assembly (8) to reach a threshold pressure, which is a pressure test of 1.5 times the nominal working pressure per known regulations. The step of injecting the liquid into the composite pressure vessel to reach the threshold pressure occurs in a first chamber (10), which is a burst containment chamber (10).

[0055] FIG. 4 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. During this step, a proof test adapter assembly (8) is secured to the first boss (4). The proof test adapter assembly (8) includes second securing means (80) for securing the proof test adapter assembly (8) to the first boss (4) and first connecting means (81) for connecting the composite pressure vessel (1) to a liquid circuit. The composite pressure vessel (1) is filled with a liquid (9) through a proof test adapter assembly (8) to reach a threshold pressure inside the composite pressure vessel (1), which is a pressure test of 1050 bar. The pressure test is maintained for the duration of the test. The test is conducted in a first chamber (10), which is a burst containment chamber (10). The test includes measuring the external volume change of the composite pressure vessel.

[0056] FIG. 5 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. During this step, a proof test adapter assembly (8) is secured to the first boss (4). The proof test adapter assembly (8) includes second securing means (80) for securing the proof test adapter assembly (8) to the first boss (4) and first connecting means (81) for connecting the composite pressure vessel (1) to a liquid circuit. The composite pressure vessel (1) is evacuated of liquid (9) through a proof test adapter assembly (8). The evacuating step occurs within a first chamber (10), which is a burst containment chamber (10).

[0057] FIG. 6 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel has a first boss (4) and a second boss (6). A cap (7) is fixed to the second boss (6), closing the second boss (6). The cap (7) and second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. FIG. 6 shows the end of the draining step, indicating that a certain amount of liquid may remain inside the composite pressure vessel (1). In this step, the proof test adapter assembly is disassembled. The second fixing means (80) remains fixed to the first boss (4), and the first connecting means for connecting the composite pressure vessel (1) to a liquid circuit is withdrawn.

[0058] Figures 7, 8, and 9 show a composite pressure vessel (1) during steps of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). In this step, a cap (7) that closes the second boss (6) is fixed to the second boss. The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. In this step, a sleeve adapter assembly (5) is fixed to the first boss (4). The sleeve adapter assembly (5) includes a suction point (52), a suction line (51), a first fixing means (50) for fixing the sleeve adapter assembly (5) to the first boss (4), and a pipe (53) for injecting gas into the composite pressure vessel. Gas is blown into the composite pressure vessel (1) as represented by the arrow (11). The remaining liquid (9) is evacuated from the composite pressure vessel (1) through the sleeve adapter assembly via the suction point (52) and suction line (51) using a blowing gas, which is air. The evacuating step is performed in the first chamber (10), which is the burst containment chamber (10). Figure 9 shows that possible rotation (12) and / or lateral movement of the suction point (52) and suction line (51) and / or pipe (53) inside the composite pressure vessel (1) can occur during this step to optimize liquid evacuation. The second fixing means of the test adapter assembly can be used as the first fixing means (50) of the sleeve adapter assembly (5) or can replace said first fixing means (50).

[0059] FIG. 10 shows a composite pressure vessel (1) during a step of the method for performing a pressure test according to the present invention, more precisely, at the end of the draining step. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is fixed to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. In this step, the sleeve adapter assembly (5) is disassembled, and the suction point, suction line, and pipe for injecting gas into the composite pressure vessel interior are removed. The remaining sole sleeve adapter assembly (5) is the first fastening means (50) for fastening the sleeve adapter assembly (5) to the first boss (4).

[0060] FIG. 11 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention, prior to the step of drying the inner liner using a dry gas. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. In this step, a pressure adapter connector (54) is secured to the first fastening means (50). Alternatively, the first fastening means (50) of the sleeve adapter assembly (5) may be replaced by a third fastening means, which may be the second fastening means used to secure a proof test adapter assembly to the composite pressure vessel. The composite pressure vessel is placed in a first chamber (10), which is a burst containment chamber (10).

[0061] FIG. 12 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention, which step is considered to be drying the inner liner. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. A pressure adapter connector (54) is secured to the first fastening means (50). Alternatively, the first fastening means (50) of the sleeve adapter assembly (5) may be replaced by a third fastening means, which may be the second fastening means used to secure a proof test adapter assembly to the composite pressure vessel. The composite pressure vessel is placed in a first chamber (10), which is a burst containment chamber (10). A vacuum is applied inside the composite pressure vessel to remove any possible traces of liquid. By applying a vacuum in the first chamber (10), a low pressure difference is maintained between the inside and outside of the composite pressure vessel to avoid any possible collapse of the inner liner. Heating of the composite pressure vessel may be performed to facilitate the removal of the liquid. The heating means is not shown in Figure 12.

[0062] FIG. 13 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention, where the inner liner is dried using a dry gas. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel includes a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and the second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. A pressure adapter connector (54) is secured to the first fastening means (50). Alternatively, the first fastening means (50) of the sleeve adapter assembly (5) may be replaced by a third fastening means, which may be the second fastening means used to secure a proof test adapter assembly to the composite pressure vessel. The composite pressure vessel is placed in a first chamber (10), which is a burst containment chamber (10). An inert gas, preferably a heated inert gas, is blown into the composite pressure vessel (1), leading to evaporation of traces of remaining liquid. Alternatively, Figure 13 shows the final step of a method for pressure testing a composite pressure vessel, which includes filling the composite pressure vessel (1) with an inert gas to avoid contamination of said composite pressure vessel (1), and the internal pressure within the composite pressure vessel (1) being higher than ambient pressure.

[0063] FIG. 14 shows a composite pressure vessel (1) during a step of a method for performing a pressure test according to the present invention. The composite pressure vessel (1) includes an inner liner (2) made of unreinforced polymer, forming an internal cavity, and enclosed in a fiber-reinforced polymer shell (3). The composite pressure vessel has a first boss (4) and a second boss (6). A cap (7) is secured to the second boss (6), closing the second boss (6). The cap (7) and second boss (6) are monoblock if the composite pressure vessel requires only one service opening during use. A pressure adapter connector (54) is secured to the first fastening means (50). Alternatively, the first fastening means (50) of the sleeve adapter assembly (5) may be replaced by a third fastening means, which may be the second fastening means used to secure a proof test adapter assembly to the composite pressure vessel. The composite pressure vessel is placed in the first chamber (10), which is a burst containment chamber (10). The composite pressure vessel (1) is filled with an inert gas, and the internal pressure of the composite pressure vessel (1) is higher than the ambient pressure. The first fixing means (50), the third fixing means, or the second fixing means of the sleeve adapter assembly (5) used to fix the proof test adapter assembly to the composite pressure vessel is covered with a cap (not shown), and the composite pressure vessel is removed from the first chamber (10) and stored. Alternatively, FIG. 13 shows a step of the composite gas production method according to the present invention prior to the step of fixing the valve to the composite pressure vessel. In this case, if the testing and production are not performed in the same chamber, the first chamber is the second chamber, and preferably the first chamber is also the second chamber.

[0064] Figures 15 and 16 show steps in a method for manufacturing a composite pressure vessel (1) according to the present invention. Figure 15 shows the removal of the first fastening means, the third fastening means, or the second fastening means of a sleeve adapter assembly used to fasten a proof test adapter to the composite pressure vessel. The removal is performed in the first chamber (10) or the second chamber. If the testing and manufacturing are not performed in the same chamber, the first chamber is the second chamber, and preferably the first chamber is also the second chamber. Figure 16 shows the step of fastening a valve assembly (13) to the composite pressure vessel. The step is performed in the first chamber (10) or the second chamber. If the testing and manufacturing are not performed in the same chamber, the first chamber is the second chamber, and preferably the first chamber is also the second chamber.

[0065] FIG. 17 shows in detail the steps of measuring the external volume change of the composite pressure vessel (1) and the location of said measurements using water as the test liquid.

[0066] Figures 18a and 18b show a specific embodiment of a sleeve adapter assembly (5) used in a method for manufacturing and testing a composite pressure vessel (1) according to the present invention. Figure 18a) is a vertical cross-sectional view of the sleeve adapter assembly (5) showing the location of a suction line (51) and a pipe (53) for injecting gas into the composite pressure vessel interior on the first fastening means (50) for fastening the sleeve adapter assembly to the first boss. Figure 18b) shows the location of different openings (54, 55, 56) for fluid communication on the first fastening means (50) for fastening the sleeve adapter assembly to the first boss. The first opening is used for sucking liquid and evacuating gas (54), the second opening is used for filling liquid (55), and the third opening is used for injecting gas (56).

[0067] FIG. 19 shows an example of an OTV (On Tank Valve) attached to a composite pressure vessel, where the OTV is an FCV cylinder valve.

[0068] Table 1 shows an example of a composite pressure vessel on which the method for performing a pressure test according to the invention is carried out.

[0069] [Table 1]

[0070] The composite pressure vessel is a Type IV vessel for 350 bar or 700 bar nominal pressure applications. The liner of the composite pressure vessel is made of a single-layer or multi-layer thermoplastic polymer. The liner material can be a polyolefin, such as polyethylene (PE), preferably high-density polyethylene (HDPE) and polyamide (PA). The liner thickness typically ranges from 2 to 7 mm. The liner is preferably exposed to temperatures ranging from -35°C to +80°C. The boss is made of metal, typically aluminum or steel; for example, the boss is 6061-T6 hard anodized aluminum or 7075-T6 grade aluminum. The composite pressure vessel is equipped with an on-tank valve (OTV). The OTV is assembled to the opening of the composite pressure vessel. The composite pressure vessel is equipped with a flow control valve (FCV) cylinder valve designed for use with high-pressure compressed hydrogen stationary or mobile storage cylinders. Modular components secured to the composite pressure vessel may include outlet adapters, manual valves, solenoid valves, bleed valves, thermally activated pressure relief devices (TPRDs), temperature sensors, and excess flow valves (EFVs).

[0071] An example process sequence is listed in Table 2.

[0072] [Table 2]

[0073] Table 3 shows some of the parameters used in the process.

[0074] [Table 3]

[0075] Depressurization will cause a decrease in temperature within the COV. The low temperature may lead to condensation and freezing of water depending on the pressure / temperature conditions during the depressurization phase.

[0076] Monitor humidity levels to control dew point and prevent water from freezing, which can block or damage equipment during depressurization. [Explanation of symbols]

[0077] 1. Composite Pressure Vessel 2 Inner Liner 3 Fiber-reinforced polymer shell 4 First Boss 5 Sleeve Adapter Assembly 6 Second Boss 7 Cap 8 Proof Test Adapter Assembly 9 liquid 10 Burst Containment Chamber (First Chamber) 11 Gas blowing direction 12 Suction points and possible rotations of suction lines and / or pipes 13 Valve Assembly 50 First fixing means 51 Suction line 52 suction points 53 Pipe 54 Pressure Adapter Connector 54 Openings used for drawing in liquids and discharging gases 55 Openings used for filling liquids 56 Opening used for gas injection 80 Secondary fixing means 81 First connection means

Claims

1. A method for pressure testing a composite pressure vessel (1), comprising the steps of: a) providing a composite pressure vessel (1) with at least one opening, preferably a single opening, for injecting a liquid, and a sleeve adapter assembly (5) with a suction point (52), a suction line (51), and a pipe (53) for injecting a gas into the interior of the composite pressure vessel (1); b. injecting said liquid (9) into said composite pressure vessel (1) through said at least one opening to reach a threshold pressure; c) measuring the external volume change of the composite pressure vessel (1); d) fixing the sleeve adapter assembly (5) to the opening and discharging the liquid (9) from the composite pressure vessel (1) through the at least one opening by blowing gas into the interior of the composite pressure vessel (1) through the pipe (53), thereby discharging the liquid (9) from the composite pressure vessel (1) through the sleeve adapter assembly (5) via the suction point (52) and the suction line (51); e. drying the inner cavity of the composite pressure vessel (1) using a dry gas; Including, the step of drying the internal cavity of the composite pressure vessel (1) is carried out at a pressure inside the composite pressure vessel that is lower than the external pressure; 1. A method for performing a pressure test on a composite pressure vessel (1), wherein the pressure test on the composite pressure vessel is performed in an orientation of the composite pressure vessel such that the sleeve adapter assembly faces downward.

2. A method for pressure testing a composite pressure vessel (1) according to claim 1, comprising the step of heating said composite pressure vessel (1).

3. 3. The method for performing a pressure test on a composite pressure vessel (1) according to claim 2, wherein the step of heating the composite pressure vessel (1) is performed during the step of drying the internal cavity of the composite pressure vessel (1).

4. 4. The method for performing a pressure test on a composite pressure vessel (1) according to any one of claims 1 to 3, wherein the liquid (9) is a liquid whose contact angle with a surface of an internal cavity of the composite pressure vessel (1) is larger than the contact angle of water with the surface of the internal cavity.

5. 5. The method for performing a pressure test on a composite pressure vessel (1) according to any one of claims 1 to 4, wherein the liquid (9) has a vaporization temperature lower than the vaporization temperature of water at atmospheric pressure or at the pressure created during the drying step e.

6. 4. The method for performing a pressure test on a composite pressure vessel (1) according to any one of claims 1 to 3, wherein the liquid (9) is selected from the group consisting of water, acetone, methanol, ethanol, isopropanol, butyl alcohol, and a mixture of at least two thereof.

7. The dry gas is N ２ , Ar, He, H ２ 7. A method for performing a pressure test on a composite pressure vessel (1) according to any one of claims 1 to 6, wherein the composite pressure vessel (1) is selected from the group consisting of: a mixture of at least two of the above;

8. 7. A method for performing a pressure test on a composite pressure vessel (1) according to any one of claims 1 to 6, wherein the dry gas is air.

9. A method for pressure testing a composite pressure vessel (1) according to any one of claims 1 to 8, wherein the dry gas is heated.

10. A method for manufacturing a composite pressure vessel (1), comprising a method for performing a pressure test on a composite pressure vessel (1) according to any one of claims 1 to 9.

11. 11. The method for manufacturing a composite pressure vessel (1) according to claim 10, comprising the step of fixing a valve assembly to the composite pressure vessel (1) after the step of drying the internal cavity of the composite pressure vessel (1) using the dry gas.

12. 10. An apparatus for carrying out a method for pressure testing a composite pressure vessel (1) according to any one of claims 1 to 9, comprising a first chamber (10) and a second chamber, said first chamber (10) comprising means for pressure testing said composite pressure vessel (1) and said second chamber comprising means for drying an internal cavity of said composite pressure vessel (1), An apparatus for carrying out a method for performing a pressure test on the composite pressure vessel (1) comprises: a sleeve adapter assembly comprising a suction point (52), a suction line (51) and first fastening means (50) configured to fasten the sleeve adapter assembly (5) to a first boss (4) of said composite pressure vessel (1); a proof test adapter assembly (8) comprising second fastening means (80) for fastening the proof test adapter assembly (8) to said first boss (4) and first connecting means (81) for connecting said composite pressure vessel (1) to a liquid circuit; - means for measuring deformations of the COPV; 1. An apparatus for carrying out a method for performing a pressure test on a composite pressure vessel (1), comprising:

13. 13. An apparatus for carrying out a method for pressure testing a composite pressure vessel (1) according to claim 12, wherein the second chamber comprises means for fixing a valve assembly to an opening in the composite pressure vessel.

14. An apparatus for carrying out a method for pressure testing a composite pressure vessel (1) according to claim 12 or 13, wherein said first chamber (10) is also said second chamber.

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