Patent ID: 8449705
Filing Date: 2013-05-28
Classification: B29C,B29D,F16L,F17C

Abstract:
1. A method for fabricating a seamless and liner-less pressure vessel as a single-piece structure of composite material, the method comprising the steps of: forming multiple hollow mandrel segments of a material that hardens into a solid but is soluble in a selected liquid, the mandrel segments including mandrel body segments and two mandrel end segments; forming one or more circularly symmetrical structural support elements of the same material as the mandrel segments, each structural support element being sized to fit internally within the mandrel segments and to join and support two adjacent mandrel segments; assembling the mandrel segments and structural support elements on a shaft, to form a hollow mandrel of desired shape and size; over-wrapping the mandrel with multiple layers of a composite material; curing the composite material to form a hollow pressure vessel; and removing the mandrel by washing it from the pressure vessel; wherein the over-wrapping step is preceded by a lay-up step in which multiple layers of a composite fabric are laid over the mandrel; and wherein the method further comprises