Patent Description:
Generally, gas storage vessels are necessary to store a variety of types of gases such as hydrogen, nitrogen, natural gas, and the like and to discharge stored gases as necessary. Particularly, since gases are in low storage density in a vessel, it is necessary to store gases at high pressure. A pressure vessel utilized in such a high-pressure environment is necessary.

For example, alternative fuel gas vehicles including fuel cell vehicles or compressed natural gas vehicles have storage system structures which vary according to a storage method of fuel gases. Currently, in consideration of a cost, a weight, and simplicity of a storage system, a compressed gas type storage method has been in the spotlight. However, since a gaseous fuel has a low energy storage density, in order to secure more mileage, it is necessary to increase a storage amount or to increase a storage pressure. Particularly, in the case of a vehicle, since there is a limitation in increasing a size of a storage tank due to a limited gas storage system mounting space, it is very significant in a tank technique to safely store gases at a higher pressure.

Also, in the case of a composite tank among fuel gas storage tanks, in order to withstand an internal pressure generated by a compressed gas, a shell is reinforced using fiber-reinforced composites having high specific strength and specific stiffness and a liner configured to maintain gas tightness is inserted therein. Here, forms of fuel gas storage tanks are classified according to materials of liners. A tank in which a metallic liner such as aluminum is inserted is sorted as a type <NUM>, and a tank in which a high-density polymer liner is inserted is sorted as a type <NUM>.

In detail, the type <NUM> has relatively high stability but has disadvantages such as a high price and low fatigue resistance. On the other hand, in comparison to the type <NUM>, the type <NUM> has advantages such as a low price and excellent fatigue resistance but has safety problems such as a leakage of hydrogen, decreasing transmission-resistant performance, and the like. Particularly, since a metallic nozzle applied to mount an external valve and a plastic material of a body differ from each other, soundness of airtightness at a boss extension part is significant.

That is, even when a pressure vessel is manufactured using a plastic liner, it is necessary to use a metallic material or a non-metallic material, which differs from the liner, for a nozzle boss. Accordingly, there is a problem of degradation of adhesion between the metallic or non-metallic nozzle boss and the plastic liner which does not occur when a metallic liner is used.

Here, to redeem the above problems, a plastic clamp is generally used for clamping a plastic liner to a metallic nozzle boss. However, this causes another problem of a difficulty in installing the clamp in the plastic liner.

As another method, a method is used of forming a groove in a nozzle boss and insertion-molding the nozzle boss in the plastic liner. However, it is not easy to implement a perfect adhesion state.

Accordingly, it is urgent to research to prevent abnormal leakage of an internally accommodated fluid by increasing adhesion between a plastic liner and a metallic or nonmetallic nozzle boss.

A pressure vessel comprising the features of the preamble portion of claim <NUM> is known from <CIT>. The boss tail portion in <CIT>, i.e. the one without through, hole forms an internal recess into which a liner portion is snuggly fitted.

Further pressure vessels are known from <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

The object of the present invention is to provide a pressure vessel having improved sealing performance.

This technical problem is solved by a sealing vessel comprising the features of claim <NUM>.

Hereinafter, a pressure vessel according to an exemplary embodiment of the present invention will be described in detail with reference to the drawings.

<FIG> is a cross-sectional view of a pressure vessel according to one embodiment of the present invention, and <FIG> is a partial cross-sectional view of the pressure vessel according to one embodiment of the present invention.

As shown in <FIG> and <FIG>, a pressure vessel <NUM> according to one embodiment of the present invention includes a boss tail portion <NUM>, a liner portion <NUM>, and a composite cover portion <NUM>.

Here, the pressure vessel <NUM> is a vessel used for accommodating a variety of fluids such as oxygen, natural gas, nitrogen, hydrogen, and the like and may be provided to selectively suction and discharge one of the fluids. Here, the fluid may be stored in the pressure vessel <NUM> at a high pressure of <NUM> bars.

Meanwhile, the boss tail portion <NUM> may include a boss extension portion <NUM> having a cylindrical shape and a boss flange portion <NUM> integrally expanding outward in a radial direction along a circumferential direction above the boss extension portion <NUM>.

Here, the boss extension portion <NUM> may have a cylindrical shape in which a lower groove <NUM> may be formed to be recessed upward from a bottom surface of a central part. Also, the boss extension portion <NUM> and the boss flange portion <NUM> are integrally formed and it may be understood that the boss extension portion <NUM> is formed below the boss tail portion <NUM> and the boss flange portion <NUM> is formed above the boss tail portion <NUM>. Here, an outer surface of the boss extension portion <NUM> may be formed to be rounded and recessed concavely inward in a radial direction along a circumferential direction from a bottom end toward a boundary area with the boss flange portion <NUM> thereabove.

Also, a bottom surface of the boss flange portion <NUM> may be formed to have a shape expanding outward in a radial direction along a circumferential direction from a boundary area with the boss extension portion <NUM> therebelow toward a top end.

A recessed groove <NUM> is be formed to be recessed downward from a top surface of the boss flange portion <NUM>. The boss flange portion <NUM> includes a protruding edge portion <NUM> extending and protruding upward while surrounding a periphery of the recessed groove <NUM>.

Here, the boss tail portion <NUM> including the boss extension portion <NUM> and the boss flange portion <NUM> may be manufactured by processing steel which is metallic, aluminum which is non-metallic, or the like, but a material thereof is not limited thereto.

Meanwhile, the composite cover portion <NUM> may be configured to surround an outer surface of the liner portion <NUM> so that a bottom end may be sealed and coupled while surrounding a bottom surface of the boss flange portion <NUM> and an outer surface of the boss extension portion <NUM>. That is, the composite cover portion <NUM> may include a bottom pressed against, covering, and surrounding the outer surface of the boss extension portion <NUM> and the bottom surface of the boss flange portion <NUM>.

Also, in the composite cover portion <NUM>, an inner surface at a center in a vertical direction which extends upward from the bottom pressed against and covering the boss tail portion <NUM> is provided to surround the liner portion <NUM>. The composite cover portion <NUM> may be formed by impregnating reinforced fiber such as carbon fiber, glass fiber, synthetic polyamide fiber, and the like into a resin such as an epoxy resin and the like to be wound or laminated, with a preset thickness, outside the boss tail portion <NUM> and the liner portion <NUM>. Accordingly, the composite cover portion <NUM> is wound or laminated outside the boss tail portion <NUM> and the liner portion <NUM> so that pressure resistance of an accommodation space 220a inside the liner portion <NUM> may be improved.

Meanwhile, the liner portion <NUM> has a container shape in which the accommodation space 220a is configured to communicate with the recessed groove <NUM> so as to accommodate a fluid therein while the bottom is sealed and coupled along a bottom surface of the boss flange portion <NUM> through integral insertion-injection molding. Also, a top of the liner portion <NUM> may be sealed and coupled, by insertion-injection molding, along a bottom surface of a boss portion <NUM> in which a through hole <NUM> is formed at a central part to pass therethrough along a vertical direction to communicate with the accommodation space 220a. Here, the boss portion <NUM> may include the same material as the boss tail portion <NUM>.

Here, the liner portion <NUM> may include a synthetic resin material different from that of the boss tail portion <NUM>. Here, the boss tail portion <NUM> may be inserted between a lower mold (not shown) and an upper mold (not shown), and a separation space (not shown) configured to communicate with the boss tail portion <NUM> may be formed between the lower mold and the upper mold.

Also, a synthetic resin is injected into the separation space and hardened so that the liner portion <NUM> may be manufactured through insertion-injection molding. Also, the top and the bottom of the liner portion <NUM> may be separately manufactured and coupled to each other through laser welding.

Meanwhile, a liner extension portion <NUM> extending inward in a radial direction along the top surface of the boss flange portion <NUM> and having a bottom surface pressed against the top surface of the boss flange portion <NUM> is formed at the liner portion <NUM>.

Also, a sealing cover portion <NUM> further extending integrally from an inner end of the liner extension portion <NUM> to have an outline of an inner surface corresponding to an outline of an outer surface of the protruding edge portion <NUM> is secondarily formed at the liner portion <NUM>.

In detail, the sealing cover portion <NUM> primarily extends and protrudes upward integrally from a radial inner end 221a of the liner extension portion <NUM> along a circumferential direction while surrounding the outer surface of the protruding edge portion <NUM>.

Also, the sealing cover portion <NUM> may secondarily be bent and extend inward in a radial direction along a circumferential direction from a top end primarily extending and protruding while surrounding a top surface of the protruding edge portion <NUM>. Subsequently, the sealing cover portion <NUM> may tertiarily be bent and extend along a circumferential direction from an inner end secondarily bent and extending while surrounding an inner surface of the recessed groove <NUM>. Also, the sealing cover portion <NUM> may quarternarily be bent and extend from a bottom end tertiarily bent and extending while sealing and covering a bottom surface of the recessed groove <NUM>.

Here, a groove having a bottom surface, which is an area quarternarily bent and extending while corresponding to an outline of an inner circumference of the recessed groove <NUM>, may be formed inward in a radial direction from the tertiarily bent and extending area of the sealing cover portion <NUM>.

Accordingly, the sealing cover portion <NUM> secondarily extends from the inner end of the liner extension portion <NUM> primarily extending along the top surface of the boss flange portion <NUM> toward an outline of an inner surface corresponding to the outer surface of the protruding edge portion <NUM> surrounding a peripheral part of the recessed groove <NUM>. Accordingly, since the sealing cover portion <NUM> seals and covers the entire top surface of the boss flange portion <NUM>, detachment between the boss tail portion <NUM> and the liner portion <NUM> is prevented even without an additional sealing device so as to notably improve sealing performance.

Meanwhile, at a top of the boss flange portion <NUM>, a shape-matching and pressing groove 213a surrounding a radial outside of the protruding edge portion <NUM> and having a cross section continuously increasing in a direction radially inwardly in width along a circumferential direction are formed to be recessed.

Here, the shape-matching and pressing groove 213a may be recessed to have a reversed-trapezoidal cross section. Also, the shape-matching and pressing groove 213a may be formed to be tilted downward in an upward direction radially inward. For example, a top surface of the shape-matching and pressing groove 213a may be formed to be horizontal to the bottom surface of the recessed groove <NUM> and may include an inner surface and a bottom surface thereof which are tilted but is not limited thereto.

In addition, a shape-matching extension portion <NUM> having a cross section increasing in width from the inner end 221a of the liner extension portion <NUM> toward an end to be pressed against and shape-matched with the shape-matching and pressing groove 213a is formed in the liner portion <NUM> along a circumferential direction at a part facing the shape-matching and pressing groove 213a.

Also, the shape-matching extension portion <NUM> may further extend radially inward from the inner end 221a of the liner extension portion <NUM> and be formed to be tilted downward in an upward direction as the shape-matching extension portion <NUM> becomes more radially inward. For example, the shape-matching extension portion <NUM> may be formed to have a top surface and a lower surface which are generally horizontal to each other and to have an inner surface and a bottom surface which are tilted. Also, the shape-matching extension portion <NUM> may be manufactured through insertion-injection molding to be pressed against and shape-matched with the shape-matching and pressing groove 213a.

Also, a sealing step 213b protruding outward from a top of the shape-matching and pressing groove 213a in a radial direction along a circumferential direction may be formed at the boss flange portion <NUM>. Here, the inner end 221a of the liner extension portion <NUM> may be pressed against and shape-matched with an outer surface of the sealing step 213b.

Accordingly, the shape-matching extension portion <NUM> of the liner portion <NUM> is pressed against and shape-matched with the shape-matching and pressing groove 213a formed to be recessed from the top of the boss flange portion <NUM> and have a cross section with a reversed-trapezoidal diameter continuously increasing radially inward along a circumferential direction. Simultaneously, the inner end 221a of the liner extension portion <NUM> is pressed against and shape-matched with the outer surface of the sealing step 213b protruding outward from the top of the shape-matching and pressing groove 213a in a radial direction along a circumferential direction. Accordingly, since a coupling force with the boss tail portion <NUM> may be firmly maintained even when the liner portion <NUM> is contracted and relaxed repetitively, sealing performance may be notably improved.

Meanwhile, a first tilted groove 213c recessed to be tilted inward in a radial direction in a downward direction may be formed on the top surface of the boss flange portion <NUM>. Also, a second tilted groove 213d recessed to be tilted outward in a radial direction in a downward direction from a position spaced radially outward apart from the first tilted groove 213c may be formed on the top surface of the boss flange portion <NUM>.

That is, the first tilted groove 213c and the second tilted groove 213d may be recessed from both sides in a radial direction that is a direction which becomes farther away therefrom in a downward direction. Here, a first recession angle between the first tilted groove 213c and the liner extension portion <NUM> may be set to correspond to a second recession angle between the second tilted groove 213d and the liner extension portion <NUM>. On a case-by-case basis, the first recession angle may be set to be different from the second recession angle.

Also, a first tilted protrusion <NUM> and a second tilted protrusion <NUM> which are shaped-matched with and inserted, respectively, into the first tilted groove 213c and the second tilted groove 213d may be formed, through insertion-injection molding, on a bottom surface of the liner extension portion <NUM> formed below the liner portion <NUM>. Here, the first tilted protrusion <NUM> and the second tilted protrusion <NUM> may be integrally formed to extend from the liner extension portion <NUM>.

Here, the first tilted protrusion <NUM> may extend to be tilted inward in a radial direction from one side of the liner extension portion <NUM> in a downward direction and be shape-matched with the first tilted groove 213c. Also, the second tilted protrusion <NUM> may extend to be tilted outward in a radial direction from the liner extension portion <NUM> at a position spaced radially outward apart from the first tilted protrusion <NUM> in a downward direction and be shape-matched with the second tilted groove 213d. That is, the first tilted protrusion <NUM> and the second tilted protrusion <NUM> may extend to both sides in a radial direction that is a direction which becomes farther away therefrom in a downward direction.

Accordingly, the first tilted groove 213c recessed to be tilted inward in the radial direction in the downward direction and the second tilted groove 213d recessed to be tilted outward in the radial direction in the downward direction while being spaced apart from the first tilted groove 213c are formed on the top surface of the boss flange portion <NUM>. Also, the first tilted protrusion <NUM> and the second tilted protrusion <NUM> of the liner extension portion <NUM> are insertion-injection molded and shape-matched with the first tilted groove 213c and the second tilted groove 213d. Accordingly, occurrence of a vertical gap and deformation between the boss tail portion <NUM> and the liner portion <NUM> may be minimized so as to minimize a fluid leakage.

Meanwhile, a peripheral shape-matching groove 213e having a cross section continuously increasing in width in a direction radially inwardly and extending along a circumferential direction is formed to be recessed from a radially outer end of the boss flange portion <NUM>. Here, the peripheral shape-matching groove 213e may be formed to be recessed from a bottom surface of the radially outer end of the boss flange portion <NUM>.

Also, a peripheral shape-matching protrusion <NUM> having a cross section increasing in width in a direction radially inwardly and extending along a circumferential direction to be pressed against and shape-matched with the peripheral shape-matching groove 213e extends and protrudes from the top of the liner portion <NUM> facing the peripheral shape-matching groove 213e.

In detail, the peripheral shape-matching protrusion <NUM> may primarily extend downward from a radial outside of the liner extension portion <NUM> to surround the radially outer end of the boss flange portion <NUM> and secondarily extend to be bent toward the peripheral shape-matching groove 213e. Here, the peripheral shape-matching protrusion <NUM> may be insertion-injection molded and pressed against and shape-matched with the peripheral shape-matching groove 213e. Here, on a case-by-case basis, the peripheral shape-matching groove 213e may be formed to be recessed from the radially outer end of the boss flange portion <NUM> so that a diameter of a cross section may continuously increase in an upward direction along a circumferential direction. Also, on a case-by-case basis, the peripheral shape-matching protrusion <NUM> may extend and protrude from the bottom of the liner portion <NUM> so that a diameter may increase in an upward direction along a circumferential direction.

Accordingly, the peripheral shape-matching protrusion <NUM> of the liner portion <NUM> is insertion-injection molded and shape-matched with the peripheral shape-matching groove 213e recessed from the radially outer end of the boss flange portion <NUM> while the diameter of the cross section continuously increases toward the radial inside along a circumferential direction. Accordingly, occurrence of a vertical gap and deformation between the boss tail portion <NUM> and the liner portion <NUM> may be minimized so as to minimize a fluid leakage.

Also, since the first tilted protrusion <NUM>, the second tilted protrusion <NUM>, and the peripheral shape-matching protrusion <NUM> of the liner portion <NUM> firmly fix the boss tail portion <NUM> in multiple directions, a fixing force may be notably improved.

Meanwhile, <FIG> is a partial cross-sectional view illustrating a modified example of the pressure vessel according to one embodiment of the present invention. In the modified example, since basic components excluding a filling-communication hole <NUM> of a boss tail portion <NUM> and a liner support portion <NUM> of a liner portion <NUM> are equal to those of the above-described one embodiment, a detailed description of the same components will be omitted.

As shown in <FIG>, a pressure vessel <NUM> according to the modified example of one embodiment of the present invention includes the boss tail portion <NUM>, the liner portion <NUM>, and a composite cover portion. Here, the boss tail portion <NUM> includes a boss extension portion and a boss flange portion <NUM> and a detailed description of the same components as those of the above-described one embodiment will be omitted.

In detail, the boss flange portion <NUM> may include a recessed groove <NUM> formed to be recessed downward from a top surface and a protruding edge portion <NUM> extending and protruding upward while surrounding a periphery of the recessed groove <NUM>.

Also, a liner extension portion <NUM> extending inward in a radial direction along the top surface of the boss flange portion <NUM> and having a bottom surface pressed against the top surface of the boss flange portion <NUM> may be primarily formed below the liner portion <NUM>.

Also, a sealing cover portion <NUM> further extending from an inner end of the liner extension portion <NUM> toward an outline of an inner surface corresponding to an outline of an outer surface of the protruding edge portion <NUM> may be secondarily formed below the liner portion <NUM>.

Meanwhile, the filling-communication hole <NUM> passing through the protruding edge portion <NUM> while an outer end communicates with an exterior of the protruding edge portion <NUM> and an inner end communicates with an inner wall of the recessed groove <NUM> may be formed to pass through the boss flange portion <NUM>.

Also, the liner support portion <NUM> insertion-injection molded inside the filling-communication hole <NUM> may be formed on the liner portion <NUM>. Here, the liner support portion <NUM> may have an outer end integrally connected to an outer portion 1223a of the sealing cover portion <NUM> and an inner end integrally connected to an inner portion 1223b of the sealing cover portion <NUM>.

Here, a plurality of such filling-communication holes <NUM> are formed to be spaced at a preset interval apart from each other along a circumferential direction of the boss flange portion <NUM>. Also, a plurality of such liner support portions <NUM> may be formed corresponding to the filling-communication holes <NUM> and may be disposed to be spaced at an interval corresponding to the interval between the filling-communication holes <NUM> apart from each other.

Meanwhile, the filling-communication hole <NUM> having the outer end communicating with the exterior of the protruding edge portion <NUM> and the inner end communicating with the inner wall of the recessed groove <NUM> may be formed to pass through the protruding edge portion <NUM>. Also, the liner support portion <NUM> of the liner portion <NUM> is pressed against and shape-matched with the filling-communication hole <NUM> through insertion-injection molding. Accordingly, since occurrence of a vertical gap and deformation between the boss tail portion <NUM> and the liner portion <NUM> is minimized and a circumferential rotation of the boss tail portion <NUM> is blocked, sealing performance may be improved.

According to the embodiment of the present invention, effects are provided as follows.

First, since a sealing cover portion secondarily extends from an inner end of a liner extension portion primarily extending along a top surface of a boss flange portion toward an outline of an inner surface corresponding to an outer surface of a protruding edge portion of the boss flange portion and integrally seals and covers the entire top surface of the boss flange portion, detachment between the boss tail portion and the liner portion may be prevented without an additional sealing device so as to improve sealing performance.

Second, since a liner support portion of a line portion is pressed and shape-matched, through insertion-injection molding, against and with a filling-communication hole having an outer end communicating with an exterior of the protruding edge portion and an inner end communicating with an inner wall surface of a recessed groove, sealing performance may be notably improved by minimizing occurrence of a vertical gap and deformation between the boss tail portion and the liner portion and blocking of the rotation of the boss tail portion.

Third, since a shape-matching extension portion of a liner portion is shape-matched, through insertion-injection molding, with a shape-matching and pressing groove formed above a boss flange portion to be recessed and have a cross section having a diameter continuously increasing in an inverted trapezoidal shape radially inward along a circumferential direction, a coupling force with the boss tail portion is firmly maintained even when the liner portion is contracted and released repetitively so that airtightness may be notably improved.

Fourth, since a first tilted protrusion and a second tilted protrusion of the liner extension portion are shape-matched, through insertion-injection molding, with a first tilted groove recessed from the top surface of the boss flange portion to be tilted radially inward in a downward direction and a second tilted groove recessed to be tilted radially outward, respectively, occurrence of a vertical gap and deformation between the boss tail portion and the liner portion may be minimized so as to minimize a fluid leakage.

Fifth, when an outer shape-matching protrusion of the liner portion is shape-matched, through insertion-injection molding, with an outer shape-matching groove recessed from an outer end of the boss flange portion to have a cross section with a diameter continuously increasing radially inward along a circumferential direction, the first tilted protrusion, the second tilted protrusion, and the outer shape-matching protrusion may firmly fix the boss tail portion in multiple directions so as to notably improve a fixing force.

Claim 1:
A pressure vessel (<NUM>) comprising:
a boss tail portion (<NUM>) comprising a boss extension portion (<NUM>) having a cylindrical shape and a boss flange portion (<NUM>) integrally expanding outward in a radial direction along a circumferential direction above the boss extension portion (<NUM>);
a liner portion (<NUM>) having a container shape in which an accommodation space (220a) is formed to accommodate a fluid therein and a bottom is sealed and coupled, through integral insertion-injection molding, along a top surface of the boss flange portion (<NUM>);
a composite cover portion (<NUM>) provided to surround an outer surface of the liner portion (<NUM>) and to have a bottom end sealed and coupled while surrounding a bottom surface of the boss flange portion (<NUM>) and an outer surface of the boss extension portion (<NUM>)
wherein the boss flange portion (<NUM>) comprises a recessed groove (<NUM>) recessed downward from a top surface and a protruding edge portion (<NUM>) extending and protruding upward while surrounding a periphery of the recessed groove (<NUM>) to thereby define a blind hole,
wherein a liner extension portion (<NUM>) extending radially inward along the top surface of the boss flange portion (<NUM>) and having a bottom surface pressed against the top surface of the boss flange portion (<NUM>) is primarily formed on the liner portion (<NUM>), and
wherein a sealing cover portion (<NUM>) extending further from an inner end of the liner extension portion (<NUM>) toward an outline of an inner surface corresponding to an outline of an outer surface of the protruding edge portion is secondarily formed,
characterized in that
the boss flange portion (<NUM>) has a shape-matching and pressing groove (213a) surrounding a radial outside of the protruding edge portion (<NUM>) and having a cross section continuously increasing inwardly in width, and
liner extension portion (<NUM>) has a shape-matching extension portion (<NUM>) having a cross section gradually increasing in width toward its end to be pressed against and shape-matched with the shape-matching and pressing groove (213a),
the boss flange portion (<NUM>) comprises a sealing step (213b) formed to protrude from a top of the shape-matching and pressing groove (213a) radially outward along a circumferential direction, and
the inner end of the liner extension portion (<NUM>) is pressed against and shape-matched with an outer surface of the sealing step (213b).