End fitting for a pressurized fluid reservoir, the reservoir comprising a liner (2) which comprises a tubular central portion (20) with a first cylindrical outer surface (21), characterized in that the end fitting (1) comprises an end portion (10) with a second cylindrical outer surface (11), the end portion (10) being configured to be positioned coaxially with respect to the tubular central portion (20), the second cylindrical outer surface (11) forming a radially flush extension of the first cylindrical outer surface (21), the end fitting (1) being configured to be mounted in a sealed manner on the outside of a neck (22) of the liner (2) by means of an annular sealing joint (4) arranged coaxially with respect to the end portion (10) in an annular groove (12) provided in an inner recess (13) of the end fitting (1) such that the internal pressure in the reservoir has a tendency to push the neck (22) radially outwards against the annular sealing joint (4).

A multilayer structure for storing hydrogen, including, from the inside, at least one sealing layer and at least one composite reinforcement layer, an innermost composite reinforcement layer being welded to an outermost adjacent sealing layer, the sealing layers being a composition predominantly of: at least one semi-crystalline polyamide thermoplastic polymer P1i, i=1 to n, n being the number of sealing layers, excluding an amide polyether block (PEBA), up to 50% by weight of impact modifier relative to the total weight of the composition, up to 1.5% by weight of plasticizer relative to the total weight of the composition, and at least one of the composite reinforcement layers of a fibrous material in the form of continuous fibers, which is impregnated with a composition predominantly of at least one semi-crystalline polyamide polymer P2j, j=1 to m, m being the number of reinforcement layers.

The present invention relates to a knob cap for a high-pressure tank including a coupling groove portion corresponding to a knob of a liner of the high-pressure tank formed in a lower surface of a body; a peripheral wing portion extending outward in a lower end of an outer circumferential surface of the body to be in contact with a surface of the liner; and a thickness conversion portion formed in the outer circumferential surface of the body to change a thickness between a center line and the outer circumferential surface.

A liquified air storage system can include a container assembly. The container assembly can be disposed on a base. The container assembly can have an interior portion and an exterior portion. The interior portion can include a reinforced concrete layer and a steel liner. The exterior portion can be disposed adjacent to the interior portion, the exterior portion including prestressed wire. A method of assembling a liquified air storage system can include assembling an interior portion of a container assembly. The interior portion can have a reinforced concrete layer and a steel liner. Next, an exterior portion of the container assembly can be assembled on the interior portion. The exterior portion can include a composite material and prestressed wires. The exterior portion can be covered with an insulation layer.

A pressure vessel includes a liner including a cylindrical body and a dorm portion continuous with at least one end of the body in an axial direction and includes a reinforced fiber sheet covering an outer side of the liner and made of fabric. The reinforced fiber sheet includes first yarns arranged on the body and the dorm portion such that yarn main axes of the first yarns extend in the circumferential direction of the liner and second yarns arranged on the body and the dorm portion such that yarn main axes of the second yarns extend in the axial direction of the liner. A total number of the first yarns or the second yarns that exist per unit length in the axial direction of the liner is smaller in the dorm portion than in the body.

A high-pressure vessel includes a liner and a reinforcing layer. The reinforcing layer includes an inner reinforcing layer and an outer reinforcing layer. Further, the inner reinforcing layer includes a first covering portion, a third covering portion, and a second covering portion. Edge surfaces of the first covering portion and the third covering portion that face each other are in contact with each other. Edge surfaces of the third covering portion and the second covering portion that face each other are also in contact with each other. The outer reinforcing layer covers the outside of the first covering portion, the third covering portion, and the second covering portion.

A pressure vessel includes: a barrel part disposed in a predefined square area and having a diameter corresponding to a length of one side of the square area; a first nozzle member disposed at one end of the barrel part; a second nozzle member disposed at an opposite end of the barrel part; and clamp rings disposed in the square area, positioned outside the barrel part, and configured to lock the first and second nozzle members to the barrel part, thereby improving spatial utilization and a degree of design freedom.

The present invention discloses a knob cap for a high-pressure tank including a first knob cap portion having a coupling groove coupled to a knob of a liner of the high-pressure tank in a lower surface, including a peripheral wing portion extending outward to be in contact with a surface of the liner to outside of a lower portion, and having a column portion in the shape of a column extending upward in a center; and a second knob cap portion integrally coupled with the first knob cap portion, having the column portion of the first knob cap portion inserted into a hollow, and including a plurality of inner grooves in the shape of a column having an upper end opened outside of the hollow and extending downward.

A high-pressure container includes a liner and a fiber layer formed of reinforcing fibers wound around an outer periphery of the liner. The fiber layer has a plurality of hoop layers in which reinforcing fibers are wound in the circumferential direction of the liner to reinforce the body portion. The reinforcing fibers used for a first hoop layer from an inner peripheral side of the fiber layer or the first hoop layer and one or more hoop layers subsequent to the first hoop layer, among the plurality of hoop layers, have a structure in which a plurality of filaments are twisted so as to be inclined with respect to a fiber bundle direction, and have a property of more easily elongating than the reinforcing fibers used for the hoop layer that is located on an outer peripheral side of the fiber layer.

A hollow molded article having a joining site where two or more split objects are welded by plastic welding and comes into contact with pressurized hydrogen, wherein an average spherulite size in a portion which is 500 μm deep inside from a surface of the hollow molded article is 20 μm or less, and a tensile strength of a test piece containing the joining site of the hollow molded article is 80% or more based on a tensile strength of a test piece not containing the joining site of the hollow molded article.