Method for producing a leak-tight vessel and leak-tight vessel obtained thereby

A method for the manufacture of a leak-tight vessel comprising a cylindrical mantle and two dome-shaped endings for the storage of a gas and/or a liquid, the vessel comprising:

• an inner barrier layer comprising a heat-sealable thermoplastic material;
• an outer shell layer comprising a fiber-reinforced heat-sealable thermoplastic material;
• an end fitting positioned at the inner side of the inner layer or in-between the inner and outer layer,
• the method comprising:
• a) mounting a removable mandrel suitable for filament winding;
• b) mounting an end fitting either to the mandrel, or after completion of step (c) described hereinafter, on the inner layer, said end fitting comprising an opening suitable for removing the mandrel there through after disassembly;
• c) forming an inner layer by winding of a heat-sealable thermoplastic material either around the mandrel or around the end fitting and the mandrel, while leaving the opening large enough for removing the mandrel after disassembly;
• d) forming an outer layer in two steps:
• (i) providing by winding around the mantle of the vessel a fabric of fiber-reinforced heat-sealable material, whereby the width of the fabric diminishes with successive windings of the fabric around the mantle;
• (ii) winding a fiber-reinforced heat-sealable material over the fabric provided in step (i) around the mantle and the dome-shaped endings, while leaving the opening large enough for removing the mandrel after disassembly;
• e) consolidating the inner layer whereby a gas-tight layer or liquid-tight layer or both is formed and whereby this step (e) is applied either concomitantly with and/or following step (c), and/or following step (d);
• f) consolidating the inner layer with the end fitting, thereby forming a gas and/or liquid tight connection between the inner layer and the end fitting, this step (f) being performed either concomitantly with or following step (e) or both;
• g) consolidating the outer layer formed in step (d) with the inner layer formed in step (e) so as to form a consolidated wall structure, this step (g) being performed either concomitantly with and/or following any of steps (e) or (f);
• and
• h) disassembling and removing the mandrel through the opening.