Pressure vessel

Abstract

The pressure vessel comprises a liner, a boss assembly, and an insert ring. The liner comprises: a main body providing a storage space; a boss coupling part connected to the main body and intersecting an axial direction; and an injection tube extending from the boss coupling part toward the inside of the main body. The boss assembly comprises: an insert boss which covers the outer surface of the boss coupling part and is fixed to the liner; and an assembly boss which is fitted into a hollow of the insert boss and is in close contact with the inner wall of the injection tube. The insert ring is coupled to both the injection tube and the insert boss to fix the injection tube and the insert boss.

Description

pressure vessel

[0001] The present invention relates to a pressure vessel, and more particularly, to a joint structure of a plastic liner and a metal boss.

[0002] A pressure vessel for storing high-pressure fluids, such as a high-pressure hydrogen tank, may include a plastic liner, a metal boss attached to the inlet of the liner, and an airtight structure installed at the interface between the liner and the boss. A reinforcing layer made of a fiber-reinforced composite may be positioned on the surface of the liner, and the boss may be connected to an external device such as a valve or adapter to enable charging and discharging of the fluid. The airtight structure is intended to prevent fluid leakage and may be constructed using O-rings, backup rings, gaskets, and the like.

[0003] Pressure vessels are used in environments where pressurization and depressurization are cyclically repeated due to fluid charging and discharging. Pressure vessels can be repeatedly subjected to pressures exceeding 700 bar. As the number of charging and discharging cycles increases, the relatively low-rigidity liner can become deformed. This can cause the O-ring to penetrate between the backup ring and the liner, damaging it. Damaged O-rings and a compromised sealing function of the backup ring can lead to fluid leakage.

[0004] The present invention aims to provide a pressure vessel capable of effectively preventing fluid leakage by suppressing deformation of a plastic liner in an environment where pressurization and depressurization are periodically repeated.

[0005] A pressure vessel according to one embodiment includes a liner, a boss assembly, and an insert ring. The liner includes a body providing a storage space, a boss coupling portion connected to the body and intersecting an axial direction, and an injection tube extending from the boss coupling portion toward the interior of the body. The boss assembly includes an insert boss covering an outer surface of the boss coupling portion and fixed to the liner, and an assembly boss fitted into a hollow portion of the insert boss and in close contact with an inner wall of the injection tube. The insert ring is coupled to both the injection tube and the insert boss to fix the injection tube and the insert boss.

[0006] The insert ring may be made of metal and may include a first region embedded in the injection tube and a second region coupled to the insert boss. A plurality of through holes may be positioned in the first region. The liner may be manufactured by insert injection molding. The liner's constituent material may fill the plurality of through holes in the injection tube to integrally connect the inner and outer portions of the insert ring. A sealing ring including an O-ring and a backup ring may be installed on the portion of the assembly boss that comes into close contact with the inner wall of the injection tube.

[0007] According to another embodiment, a pressure vessel includes a liner, an insert boss, an assembly boss, and an insert ring. The liner includes a body, a curved portion connected to the body, a first coupling portion and a second coupling portion branched from the curved portion and positioned at a distance from each other in an axial direction, and an injection tube extending toward the inside of the body from the second coupling portion. The insert boss includes a first tubular portion parallel to the axial direction, and a wing portion connected to the first tubular portion and surrounded by the first coupling portion and the second coupling portion and fixed to the liner, and has a first hollow portion and a second hollow portion extending in the axial direction. The assembly boss includes a second tubular portion fitted into the first hollow portion, and a third tubular portion fitted into the second hollow portion and in close contact with an inner wall of the injection tube. The insert ring includes a first region embedded in the injection tube and a second region coupled to the wing portion, and fixes the injection tube and the wing portion.

[0008] The second connecting portion may be axially intersecting, may be located inward of the first connecting portion, and may include a first wedge-shaped projection extending toward the wing portion. The wing portion may have a first groove positioned thereon for receiving the first projection.

[0009] The liner may include a wing retainer located where the curved portion and the first and second joining portions meet. The wing retainer may surround an edge of the wing portion and may include a second wedge-shaped protrusion extending toward the edge of the wing portion. A second groove may be located on the edge of the wing portion to accommodate the second protrusion.

[0010] The outer surface of the wing portion may include a first-stage region that is in contact with the edge of the wing portion and covered by the first joint portion, and a second-stage region that is in contact with the first tubular portion and is positioned higher than the first-stage region by the thickness of the first joint portion. A sealing ring including an O-ring and a backup ring may be installed in a portion of the third tubular portion that is in contact with the inner wall of the injection tube.

[0011] The insert ring may be made of metal and may be positioned parallel to the axial direction. A plurality of through holes may be positioned in the first region. The plurality of through holes may be positioned at a distance from each other along the circumference of the insert ring and may be arranged in two or more rows along the axial direction.

[0012] The liner can be manufactured by insert injection molding. The liner's constituent material can fill multiple through holes in the injection tube to integrally connect the inner and outer portions of the insert ring. A groove including a second region can be positioned on the inner surface of the wing portion. The height of the first region along the axial direction can be greater than the height of the second region.

[0013] The pressure vessel of the present embodiment can improve sealing performance by minimizing the gap between the inner surface of the injection tube and the assembly boss under high pressure, and can prevent deformation and damage to the sealing ring located between the gap, thereby improving the durability of the sealing ring in an environment where pressurization and depressurization are periodically repeated. In addition, since the insert ring is attached to both the injection tube and the insert boss, the fixing force of the injection tube and the insert boss in the axial direction can be increased, and fluid leakage can be effectively prevented.

[0014] Figure 1 is a perspective view of a pressure vessel according to one embodiment.

[0015] Figure 2 is a partially enlarged cross-sectional view of the pressure vessel shown in Figure 1.

[0016] Figure 3 is a cross-sectional view of the pressure vessel shown in Figure 2 in an exploded state.

[0017] Fig. 4 is a perspective view of an assembly boss of the pressure vessel illustrated in Fig. 2.

[0018] Figure 5 is a partial cutaway perspective view of the insert boss and insert ring of the pressure vessel illustrated in Figure 2.

[0019] Fig. 6 is a perspective view of an insert ring in the pressure vessel illustrated in Fig. 2.

[0020] Figures 7 and 8 are schematic diagrams showing the manufacturing process of the liner illustrated in Figure 2.

[0021] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0022] FIG. 1 is a perspective view of a pressure vessel according to one embodiment, FIG. 2 is a partially enlarged cross-sectional view of the pressure vessel illustrated in FIG. 1, and FIG. 3 is an exploded cross-sectional view of the pressure vessel illustrated in FIG. 2.

[0023] Referring to FIGS. 1 to 3, a pressure vessel according to the present embodiment includes a liner (100) made of a plastic material, a boss assembly (200) made of a metal material coupled to the inlet of the liner (100), and an insert ring (300) made of a metal material coupled to the liner (100) and the boss assembly (200). The pressure vessel may further include a sealing ring (400) positioned at the interface of the liner (100) and the boss assembly (200).

[0024] The liner (100) may be configured in a roughly cylindrical shape with an interior that is hollow and both sides except for the inlet are blocked. The liner (100) can store various fluids, such as liquefied petroleum gas, compressed natural gas, light hydrocarbons (methane, propane, butane, etc.), and hydrogen gas, by compressing them at high pressure in the interior space. The liner (100) may be manufactured using a polymer resin, such as a polyolefin resin or a polyamide resin, to reduce weight.

[0025] The liner (100) may be surrounded by a reinforcing layer (not shown) made of carbon fiber reinforced plastics (CFRP). The reinforcing layer may be formed by surrounding the outer surface of the liner (100) with carbon filaments, such as carbon fibers, impregnated with a resin, such as epoxy, and cured. The reinforcing layer provides structural strength and rigidity to the liner (100) so that it can withstand high pressure.

[0026] The liner (100) may include a cylindrical body (110) with a closed bottom, a curved portion (120) connected to the body (110), a first coupling portion (130) and a second coupling portion (140) branched from the curved portion (120) and positioned at a distance from each other, and an injection tube (150) extended from the second coupling portion (140) toward the inside of the body (110) along the axial direction of the pressure vessel (the Z direction in the drawing).

[0027] The curved portion (120) may be formed as a convex curved surface toward the outside of the liner (100). The first connecting portion (130) may be configured to extend from the curved portion (120) toward the central axis of the liner (100) (line CC in FIG. 2) while maintaining the same or similar curvature as the curved portion (120). The second connecting portion (140) may be a portion that branches from the curved portion (120) so as to roughly intersect the axial direction (Z direction) and may be located on the inside (lower side based on the drawing) of the first connecting portion (130).

[0028] The second coupling portion (140) is positioned at a distance from the first coupling portion (130) along the axial direction (Z direction) and may be formed as a convex curved surface or an inclined surface toward the inside of the main body (110). The length of the second coupling portion (140) along the radial direction (R direction) of the pressure vessel may be greater than the length of the first coupling portion (130). The injection tube (150) is a portion that extends from the center of the second coupling portion (140) toward the inside of the main body (110) and is positioned parallel to the axial direction (Z direction). The second coupling portion (140) may be referred to as a boss coupling portion.

[0029] The boss assembly (200) may include an insert boss (210) that covers the outer surface of the second coupling portion (140) and is fixed to the first and second coupling portions (130, 140), and an assembly boss (250) that is fixed to the insert boss (210) and the injection tube (150). An insert ring (300) is fixed to both the injection tube (150) and the insert boss (210) to increase the fixing force between the liner (100) and the boss assembly (200). The insert boss (210) and the assembly boss (250) may be made of aluminum, and the insert ring (300) may be made of stainless steel, but is not limited to these examples.

[0030] FIG. 4 is a perspective view of an assembly boss in the pressure vessel illustrated in FIG. 2, FIG. 5 is a partial cutaway perspective view of an insert boss and an insert ring in the pressure vessel illustrated in FIG. 2, and FIG. 6 is a perspective view of an insert ring in the pressure vessel illustrated in FIG. 2.

[0031] Referring to FIGS. 2 to 6, the insert boss (210) may include a first tubular portion (211) parallel to the axial direction (Z direction) and a wing portion (212) connected to one side (lower side based on the drawing) of the first tubular portion (211) and extending along the radial direction (R direction). A hollow portion (213) penetrating the insert boss (210) along the axial direction (Z direction) is located at the center of the insert boss (210).

[0032] The hollow (213) can be divided into a first hollow (213a) located across the entire first tubular portion (211) and a part of the wing portion (212), and a second hollow (213b) located on the remainder of the wing portion (212). The diameter of the first hollow (213a) can be larger than the diameter of the second hollow (213b), and the diameter of the second hollow (213b) can be the same as the inner diameter of the injection tube (150). A screw thread for fastening with an assembly boss (250) can be provided on the inner wall of the insert boss (210) surrounding the first hollow (213a).

[0033] The wing portion (212) can be fixed between the first coupling portion (130) and the second coupling portion (140). The inner surface of the wing portion (212) facing the second coupling portion (140) is configured in the same shape as the second coupling portion (140) so that it can be in close contact with the second coupling portion (140). The outer surface of the wing portion (212) can be divided into a first-stage region (212a) in contact with the edge, and a second-stage region (212b) located between the first-stage region (212a) and the first tubular portion (211). The first-stage region (212a) is covered by the first coupling portion (130), and the second-stage region (212b) can be located higher than the first-stage region (212a) by the thickness of the first coupling portion (130).

[0034] The second connecting portion (140) may be composed of an inclined portion (140a) branched from the curved portion (120) and a flat portion (140b) located on the inner side of the inclined portion (140a) and in contact with the injection tube (150). The portion where the curved portion (120), the first connecting portion (130), and the inclined portion (140a) meet may be a portion having the largest thickness in the liner (100) and may be in contact with the edge of the wing portion (212). For convenience, the portion in the liner (100) that is in contact with the edge of the wing portion (212) is referred to as a wing fixing portion (160).

[0035] At least one pair of protrusion-groove joints may be provided at the interface between the liner (100) and the insert boss (210) to increase the fixing force between the liner (100) and the insert boss (210). For example, a first protrusion-groove joint (510) may be provided at the interface between the inner surface of the wing portion (212) and the flat portion (140b) to increase the fixing force between the liner (100) and the insert boss (210) along the axial direction (Z direction). In addition, a second protrusion-groove joint (520) may be provided at the interface between the wing fixing portion (160) and the edge of the wing portion (212) to increase the fixing force between the liner (100) and the insert boss (210) along the radial direction (R direction).

[0036] The first protrusion-groove joint (510) may be composed of a wedge-shaped first protrusion (511) extending from the flat portion (140b) toward the wing portion (212), and a first groove portion (512) provided on the inner surface of the wing portion (212) to accommodate the first protrusion (511). The second protrusion-groove joint (520) may be composed of a wedge-shaped second protrusion (521) extending from the wing fixing portion (160) toward the edge of the wing portion (212), and a second groove portion (522) provided on the edge of the wing portion (212) to accommodate the second protrusion (521).

[0037] The assembly boss (250) is fitted into the hollow (213) of the insert boss (210) and is in close contact with the inner wall of the injection tube (150). The assembly boss (250) may be composed of a second tubular portion (251) positioned in the first hollow (213a), and a third tubular portion (252) positioned across the second hollow (213b) and the inside of the injection tube (150). At the center of the assembly boss (250), a hollow (253) is positioned that penetrates the assembly boss (250) along the axial direction (Z direction).

[0038] A flange (254) covering the upper end of the first tubular portion (211) may be provided on the upper end of the assembly boss (250), and a screw thread for fastening with the insert boss (210) may be provided on the outer wall of the second tubular portion (251). The outer diameter of the second tubular portion (251) may be larger than the outer diameter of the third tubular portion (252), and the third tubular portion (252) may be in close contact with the inner wall of the wing portion (212) surrounding the second hollow portion (213b) and the inner wall of the injection tube (150).

[0039] A sealing ring (400) is provided on a portion of the third tubular portion (252) facing the inner wall of the injection tube (150), thereby improving the sealing performance of the interface between the injection tube (150) and the assembly boss (250). The third tubular portion (252) may have a ring-shaped groove on a portion facing the inner wall of the injection tube (150), and the sealing ring (400) may be fitted into this groove. The sealing ring (400) may be composed of an O-ring (410) and a backup ring (420). Based on the drawing, the backup ring (420) may be positioned on the upper side of the O-ring (410).

[0040] The O-ring (410) may be made of an elastic rubber material. For example, the O-ring (410) may include any one of fluoroelastomer, acrylonitrile-butadiene rubber, ethylene-propylene rubber, and silicone rubber. Fluoroelastomer is a trademark of Chemours, Viton. TM) may be included. The ethylene-propylene rubber may include EPM (Ethylene-Propylene Monomer) rubber, EPDM (Ethylene-Propylene Diene Monomer) rubber, etc. The backup ring (420) may be made of, for example, polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), etc.

[0041] The materials described above have excellent elasticity, wear resistance, and mechanical properties, making them suitable as materials for O-rings (410) and backup rings (420). In the drawing, one set of O-rings (410) and backup rings (420) is illustrated, but the number of O-rings (410) and backup rings (420) is not limited to the illustrated example. For example, two or more sets of O-rings and backup rings may be provided at a distance from each other along the axial direction (Z direction).

[0042] The insert ring (300) is formed in a cylindrical shape with a constant height and thickness, and is coupled to both the injection tube (150) and the insert boss (210). The inner diameter of the insert ring (300) may be larger than the inner diameter of the injection tube (150), and the outer diameter of the insert ring (300) may be smaller than the outer diameter of the injection tube (150).

[0043] The insert ring (300) can be divided into a first region (310) embedded in the injection tube (150) and a second region (320) fitted into the inner surface of the wing portion (212). The height (h1) (see FIG. 6) of the first region (310) measured along the axial direction (Z direction) can be greater than the height (h2) (see FIG. 6) of the second region (320).

[0044] A plurality of through holes (301) may be positioned in the first region (310) to penetrate the first region (310) in a radial direction (R direction), and a constituent material of the liner (100) may fill the plurality of through holes (301). The constituent material of the liner (100) filled in the plurality of through holes (301) may integrally connect the inner and outer portions of the first region (310) to effectively increase the fixing force between the liner (100) and the insert ring (300).

[0045] A plurality of through holes (301) may be positioned at a distance from each other along the circumferential direction of the insert ring (300) and may be arranged in at least two rows along the axial direction (Z direction). A groove for accommodating a second region (320) may be provided on the inner surface of the wing portion (212) of the insert boss (210), and the second region (320) may be fitted into the groove and coupled to the wing portion (212). The liner (100) may be integrally manufactured with the assembly of the insert boss (210) and the insert ring (300) by insert injection molding.

[0046] Figures 7 and 8 are schematic diagrams showing the manufacturing process of the liner illustrated in Figure 2.

[0047] Referring to FIGS. 7 and 8, a mold (600) having a cavity (601) corresponding to the shape of the liner may be prepared to manufacture a liner, and an assembly of an insert boss (210) and an insert ring (300) may be placed inside the mold (600). Subsequently, a molten polymer resin may be injected into the cavity (601) at high pressure to fill the cavity (601), and the polymer resin filling the cavity (601) may be solidified to complete the liner. In FIGS. 7 and 8, arrows indicate the movement path of the molten polymer resin.

[0048] Referring to FIGS. 2 to 8, the injection tube (150) of the liner (100) can be fixed integrally with the first region (310) by filling the through hole (301) of the first region (310) while surrounding the inner and outer surfaces of the first region (310) of the insert ring (300). The first coupling portion (130) and the second coupling portion (140) of the liner (100) can cover the wing portion (212) of the insert boss (210) from above and below, and the wing fixing portion (160) of the liner (100) can surround the edge of the wing portion (212) from the outside.

[0049] In this way, the liner (100) can increase the fixing force with the insert boss (210) by surrounding the wing portion (212) of the insert boss (210) in three directions, and can further increase the fixing force with the insert boss (210) by the first and second protrusion-groove joints (510, 520).

[0050] The entire liner (100) can be manufactured through a single injection molding process. Alternatively, the liner (100) can be divided into two or three parts, each of which can be manufactured through injection molding. The two or three parts can then be joined together through thermal welding, laser welding, or the like to form a single liner (100).

[0051] After the liner (100) is manufactured, as shown in FIG. 3, an assembly boss (250) having a sealing ring (400) can be inserted into the hollow (213) from the upper side of the insert boss (210) and fitted into the insert boss (210). This combined structure of the insert boss (210) and the assembly boss (250) can facilitate the replacement of the sealing ring (400), thereby enhancing the convenience of maintenance.

[0052] The injection tube (150) of the liner (100) has high rigidity due to the insert ring (300) embedded therein, and can maintain a constant interface with the assembly boss (250). That is, the injection tube (150), whose rigidity is increased by the insert ring (300), can be more firmly attached to the third tubular portion (252) of the assembly boss (250), and can prevent a gap from occurring between the injection tube (150) and the sealing ring (400).

[0053] Therefore, the pressure vessel of the present embodiment can minimize damage to the sealing ring (400) and increase the durability of the sealing ring (400) in an environment where pressurization and depressurization are periodically repeated. In addition, since the insert ring (300) is coupled to both the injection tube (150) and the insert boss (210), the fixing force of the injection tube (150) and the insert boss (210) in the axial direction (Z direction) can be increased, and leakage of fluid can be effectively prevented.

[0054] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. A liner including a main body providing a storage space, a boss joint connected to the main body and intersecting the axial direction, and an injection tube extending from the boss joint toward the inside of the main body; A boss assembly including an insert boss that covers the outer surface of the boss joint and is fixed to the liner, and an assembly boss that is fitted into the hollow of the insert boss and is in close contact with the inner wall of the injection tube; and A pressure vessel including an insert ring coupled to both the injection tube and the insert boss to secure the injection tube and the insert boss.

2. In paragraph 1, The above insert ring is made of metal and includes a first region embedded in the injection tube and a second region coupled to the insert boss, A pressure vessel having a plurality of through holes positioned in the first region.

3. In paragraph 2, The above liner is manufactured by insert injection molding, A pressure vessel in which the constituent material of the liner fills the plurality of through holes in the injection tube, thereby integrally connecting the inner and outer parts of the insert ring.

4. In any one of paragraphs 1 to 3, A pressure vessel in which a sealing ring including an O-ring and a backup ring is installed in a portion of the above assembly boss that is in close contact with the inner wall of the injection pipe.

5. A liner including a main body, a curved portion connected to the main body, a first coupling portion and a second coupling portion branched from the curved portion and positioned at a distance from each other along an axial direction, and an injection tube extending from the second coupling portion toward the inside of the main body; An insert boss having a first tubular portion parallel to the axial direction, a wing portion connected to the first tubular portion and surrounded by the first coupling portion and the second coupling portion and fixed to the liner, and having a first hollow portion and a second hollow portion extending along the axial direction; An assembly boss including a second tubular part fitted into the first hollow part, and a third tubular part fitted into the second hollow part and in close contact with the inner wall of the injection tube; and A pressure vessel comprising a first region embedded in the injection tube and a second region coupled to the wing portion, and including an insert ring that secures the injection tube and the wing portion.

6. In paragraph 5, The second connecting portion intersects the axial direction, is located on the inside of the first connecting portion, and includes a wedge-shaped first protrusion extending toward the wing portion, A pressure vessel having a first groove for accommodating the first protrusion located in the wing portion.

7. In paragraph 5 or 6, The liner includes a wing fixing portion positioned where the curved portion, the first connecting portion, and the second connecting portion meet, The wing fixing member surrounds the edge of the wing portion and includes a wedge-shaped second protrusion extending toward the edge of the wing portion, A pressure vessel having a second groove positioned on the edge of the wing portion to accommodate the second protrusion.

8. In any one of paragraphs 5 to 7, A pressure vessel in which the outer surface of the wing portion includes a first stage region that is in contact with the edge of the wing portion and covered by the first connecting portion, and a second stage region that is in contact with the first tubular portion and is positioned higher than the first stage region by the thickness of the first connecting portion.

9. In any one of paragraphs 5 to 8, A pressure vessel in which a sealing ring including an O-ring and a backup ring is installed in a portion of the third tubular section that is in close contact with the inner wall of the injection tube.

10. In any one of paragraphs 5 to 9, The above insert ring is made of metal and is positioned parallel to the axial direction, A plurality of through holes are located in the first region above, A pressure vessel in which the plurality of through holes are positioned at a distance from each other along the circumferential direction of the insert ring and are arranged in two or more rows along the axial direction.

11. In paragraph 10, The above liner is manufactured by insert injection molding, A pressure vessel in which the constituent material of the liner fills the plurality of through holes in the injection tube, thereby integrally connecting the inner and outer parts of the insert ring.

12. In any one of paragraphs 5 to 11, A groove including the second region is located on the inner surface of the wing portion, A pressure vessel in which the height of the first region along the axial direction is greater than the height of the second region.

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