Collapsible and flexible sub sea pipe for transporting fluid e.g. oil across body of water, has stiffener made of thermoplastics material such that stiffener elongates to less than its elongation threshold when pressure sheath collapses

摘要

The pipe includes at least two armor plies (3-6) set concentrically around at least one pressure sheath (7). At least one stiffener (8,9) is set at the sheath inner surface (7a), and is made of thermoplastics material such that the stiffener elongates to less than its elongation threshold when pressure sheath collapses. The pressure sheath collapses when external pressure is greater than its internal pressure.