Pressure vessel

1. A pressure vessel comprising:

a boss portion comprising a boss extension portion having a cylindrical shape in which a through hole is formed at a central part to pass therethrough and a boss flange portion formed below the boss extension portion and integrally expanding outward in a radial direction along a circumferential direction in which the through hole extends in a vertical direction;

a liner portion having a container shape in which an accommodation space configured to communicate with the through hole is formed to accommodate a fluid therein while a top of the liner portion is insertion-injection molded and seal-coupled along a bottom surface of the boss flange portion; and

a sealing portion seal-coupled to a boundary area between a bottom of the boss flange portion and the top of the liner portion to block a leakage of the fluid accommodated in the accommodation space,

wherein a sealing step protruding outward in the radial direction is formed along the circumferential direction on the boss flange portion,

wherein a sealing groove facing a radially outer end of the sealing step is formed to be recessed upward below an inner end of the liner portion extending along the bottom surface of the boss flange portion,

wherein the sealing portion comprises:

a sealing plate surrounding a radial outside of the through hole along a circumferential direction, wherein a radially inward top surface of the sealing plate contacts a bottom surface of the sealing step, and a radially outward top surface of the sealing plate, which is located outward than the radially inward top surface in the radial direction, contacts a bottom surface of a liner extension portion formed above the liner portion; and

a sealing shape-matching portion integrally extending upward from a top of the sealing plate while a radially inner surface of the sealing shape-matching portion comes into surface contact with the radially outer end of the sealing step and a top surface of the sealing shape-matching portion is pressed against and shape-matched with the sealing groove,

wherein a first sealing protrusion and a third sealing protrusion extend upward from the radially inward top surface and the radially outward top surface of the sealing plate, respectively, and

wherein a second sealing protrusion integrally extending and protruding toward the sealing groove is formed along a circumferential direction on the top surface of the sealing shape-matching portion so that a top end of the second sealing protrusion is elastically pressurized toward the sealing groove.

2. The pressure vessel of claim 1 , wherein a shape-matching and pressing groove surrounding a radial outside of the through hole and having a cross section continuously increasing toward an end of the shape-matching and pressing groove is formed along the circumferential direction to be recessed from the bottom surface of the boss flange portion, and

wherein a shape-matching expansion portion is formed on a part of the liner portion facing the shape-matching and pressing groove through insertion-injection molding to be pressed against and shape-matched with the shape-matching and pressing groove.

3. The pressure vessel of claim 1 , wherein the first sealing protrusion integrally extends and protrudes from the radially inward top surface of the sealing plate toward the bottom surface of the sealing step along a circumferential direction so that a top end of the first sealing protrusion is elastically pressurized toward the bottom surface of the sealing step.

4. The pressure vessel of claim 1 , wherein the third sealing protrusion integrally extends and protrudes from the radially outward top surface of the sealing plate toward a bottom surface of the liner extension portion along a circumferential direction so that a top end of the third sealing protrusion is elastically pressurized toward the bottom surface of the linear extension portion.

5. The pressure vessel of claim 1 , wherein a bottom surface of the sealing plate is formed to be a planarized surface, and

wherein the sealing portion further comprises a sealing pressurizing portion having a ring shape in which a top surface comes into surface contact with the bottom surface of the sealing plate and a radially inner end is pressed against the boss flange portion.

6. The pressure vessel of claim 5 , wherein the sealing portion further comprises a pressurizing nut having a ring shape in which a top surface comes into surface contact with a bottom surface of the sealing pressurizing portion and a fastening screw thread is formed on a radial inside, and

wherein a screw coupling portion is formed on one side of a bottom of the boss flange portion facing the radial inside of the pressurizing nut to allow the fastening screw thread to be coupled thereto.

7. The pressure vessel of claim 1 , wherein a height of a top surface of the sealing groove is set to be a height corresponding to a central part between a top end and a bottom end of the sealing step.

8. The pressure vessel of claim 1 , wherein a first tilted groove is formed to be recessed in the bottom surface of the boss flange portion to be tilted inward in a radial direction in an upward direction and a second tilted groove spaced outward apart from the first tilted groove in a radial direction is formed to be recessed to be tilted outward in the radial direction in the upward direction, and

wherein a first tilted protrusion and a second tilted protrusion which are inserted into and shape-matched with the first tilted groove and the second tilted groove, respectively, are formed on a top surface of the liner extension portion formed above the liner portion.

9. The pressure vessel of claim 1 , wherein a peripheral shape-matching groove having a cross section continuously increasing toward an end of the peripheral shape-matching groove is formed along the circumferential direction to be recessed from a radially outer end of the boss flange portion, and

wherein a peripheral shape-matching protrusion having a diameter increasing toward a radial inside along a circumferential direction extends and protrudes from a top of the liner portion facing the peripheral shape-matching groove to be pressed against and shape-matched with the peripheral shape-matching groove.