Organic composite gas storage tank

An organic composite gas storage tank comprising a hollow central portion formed integrally with first and second end portions and which defines a longitudinal tank axis, the first end portion comprising:

• (a) a hollow truncated conical region comprised of a wall of a single internal wall material which meets the hollow central portion at a first end thereof, the outer and inner radii of the hollow truncated conical region decreasing in a direction along the longitudinal tank axis away from the hollow central portion;
• and
• (b) a cylindrical region which meets an end of the hollow truncated conical region remote from the hollow central portion of the tank,
• wherein the tank further comprises:
• (i) a hollow metal end-fitting having a hollow cylindrical portion and a hollow truncated conical portion extending from the hollow cylindrical portion towards the hollow central portion of the tank, the radially outer surface of the hollow cylindrical portion being in contact with the radially inner surface of the cylindrical region of the first end portion, and the radially inner surface of the hollow cylindrical portion being at least in part in contact with stored gas in use of the tank, the hollow truncated conical portion of the metal end-fitting being embedded within the single internal wall material of the wall of the hollow truncated conical region of the first end portion such that both radially outer and radially inner surfaces of the hollow truncated conical portion of the metal end-fitting contact the single internal wall material of the wall of the hollow truncated conical region of the first end portion, the first end portion of the tank and the metal end-fitting forming a single continuous leakage path of the tank from the interior to the exterior thereof by (a) contact of the hollow truncated conical portion of the metal end-fitting with internal material of the wall of the hollow truncated conical region of the first end portion and (b) contact of the radially outer surface of the hollow cylindrical portion of the metal end-fitting with the radially inner surface of the cylindrical region of the first end portion;
• and
• (ii) an organic fiber winding extending at least between first and second positions along the length of the tank which coincide with the hollow truncated conical region of the first end portion and the hollow cylindrical portion respectively, the organic fiber winding having windings in planes which are inclined to the longitudinal tank axis.