Patent ID: 7090736

Claim:
A method of making a filament wound composite pressure vessel comprising the steps of providing a thermoplastic liner having a cylindrical sidewall, convex end walls and at least one access opening in at least one of said walls, providing a reinforcing filament commingled in a thermoplastic matrix, said thermoplastic matrix having a melting point lower than a melting point of said liner, helically winding said filament and matrix about said walls to provide a wound liner, partially filling said liner with a liquid through an access opening to a level below said access opening, closing said access opening and providing a pressure relief valve at said access opening, said valve being adaptable to vent and maintain the interior of the liner at a set constant predetermined pressure, rotating and heating said wound liner to a temperature sufficient to vaporize a portion of said liquid to pressurize said liner at said set constant predetermined pressure and sufficient to fuse the thermoplastic matrix but insufficient to significantly soften said thermoplastic liner.