Collapsible containers are an attractive alternative to surface-tension propellant management devices (PMDs) for handling cryogenic liquids, as the collapsible container comparatively may 1) allow higher expulsion flow rates than vanes and sponges, 2) significantly reduce operational complexity, and 3) thermally insulate the propellant from environmental heat leaks. Furthermore, while historical cryogenic collapsible containers suffered from the low ductility of polymer films at cryogenic temperatures, the technology disclosed herein shows that the incorporation of folded patterns into the collapsible container substantially increases the reusability of the cryogenic PMD.

A modular subsea fluid storage unit has a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

A pressure vessel and a method of manufacturing the pressure vessel is provided that reduces leaks in type IV pressure vessels having a liner with a corrugated section. The method includes providing a liner having a tubular portion having a corrugated section with circumferential corrugations providing alternating ridges and grooves arranged from one end to an opposing end of the corrugated section, applying a barrier to an outer surface of the corrugated section from one end to an opposing end of the corrugated section such that air voids are formed in annular cavities between the liner and the barrier; and applying resin to an outer surface of the barrier. The barrier prevents intrusion of the resin between the barrier and the liner in the corrugated section.

A modular subsea fluid storage unit comprises a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

A Venturi filling system having a first filling coupler configured to be coupled to a first set of fittings disposed at a first tank end of a tank; a second filling coupler configured to be coupled to a second set of fittings disposed at a second tank end of the tank; and a Venturi assembly that includes: a Venturi mixing chamber, the Venturi mixing chamber communicating with the first filling coupler; a Venturi nozzle configured to introduce a first flow of fluid from a fluid source to the Venturi mixing chamber of the Venturi assembly; and an suction inlet communicating with the second filling coupler and coupled with the Venturi chamber and configured to receive a second flow of fluid originates from the second filling coupler such that the second flow of fluid flows into the Venturi chamber and mixes with the first fluid flow within the Venturi mixing chamber.

A tank filling system comprising a first filling coupler that couples to a first set of fittings disposed at a first tank end of a tank; a second filling coupler that couples to a second set of fittings disposed at a second tank end of the tank; a fluid source; a set of fluid lines and one or more fluid valves that communicate fluid from the fluid source to the first and second filling couplers; and a computing device configured to control the one or more fluid valves. In some examples, the tank can comprise an elongated folded tank having a plurality of elongated rigid tubing portions having a first diameter, a plurality of connector portions having a second diameter that is smaller than the first diameter and flexible corrugations and a rigid cuff, and taper portions disposed between and coupling successive tubing portions and connector portions.

One aspect includes a folded tank assembly having an elongated tank that extends between a first and second end. The elongated tank has a plurality of elongated rigid tubing portions having a first diameter, a plurality of connector portions having a second diameter that is smaller than the first diameter, and taper portions disposed between and coupling successive tubing portions and connector portions. The elongated tank is folded to define a folded tank body having a first and second tank body end, with the elongated rigid tubing portions extending between the first and second tank body ends and with the plurality of connector portions being disposed at one of the first or second tank body ends. A first tank mount is disposed at the first tank body end and a second tank mount disposed at the second tank body end.

A set of fittings for a fuel tank including an elongated stem and a ferrule. The stem includes an elongated coupling body at one end configured to couple within a cavity defined by an end of a fuel tank liner. The ferrule includes a ferrule body having a first ferrule end and a second ferrule end; a lip defining a coupling orifice at the first ferrule end with the stem being operable to extend though the coupling orifice and engaging the lip, and a ferrule cavity defined by the ferrule body that extends between the first and second ferrule ends and opening to the coupling orifice at the first ferrule end and a ferrule opening at the second ferrule end, the ferrule cavity configured to surround the end of the fuel tank liner.