Vehicles incorporating tanks for carrying cryogenic fluids and methods for forming such tanks
A tank for carrying cryogenic fluids and/or hydrogen peroxide and a method of forming the same is provided. A vehicle incorporating such a tank as part of the vehicle structure is also provided. The tank includes an inner wall compatible with the fluid to be carried, an outer wall, and a spacing layer sandwiched between the two walls. In an exemplary embodiment, the outer wall forms part of the structure of a flight vehicle.
1 . A propelled vehicle for traveling through an environment, the vehicle comprising:
an outer wall exposed to the environment in which it is traveling;
an inner wall compatible with a cryogenic fluid; and
an insulating layer sandwiched between the two walls, wherein said inner and outer walls act together to define a rigid overall structural wall of a tank comprising said insulating layer for carrying the cryogenic fluid.
2 . The vehicle as recited in claim 1 wherein the inner wall has a coefficient of thermal expansion no greater than about 12 ppm/° K.
3 . The vehicle as recited in claim 2 wherein the inner wall comprises a reinforced fluoropolymer.
4 . The vehicle as recited in claim 3 wherein the inner wall comprises a glass fiber reinforced fluoropolymer.
5 . The vehicle as recited in claim 3 wherein the fluoropolymer is selected from the group of fluoropolymers consisting of polytetrafluoroethylene, polychlorotrifluoroethylene and perfluoroalkoxy.
6 . The vehicle as recited in claim 1 wherein the inner wall comprises an iron-nickel alloy.
7 . The vehicle as recited in claim 7 wherein said iron-nickel alloy is selected from the group of iron nickel alloys consisting of Invar 36, Incoloy 903, Incoloy 909 and Nilo 36.
8 . The vehicle as recited in claim 1 further comprising an adhesive bonding the inner wall to the insulating layer, wherein the adhesive is a flexible epoxy adhesive.
9 . The vehicle as recited in claim 1 further comprising an adhesive bonding the inner wall to the insulating layer, wherein the adhesive is flexible having a maximum elongation at the tank operating temperatures of not less than about 1%.
10 . The vehicle as recited in claim 1 further comprising an adhesive bonding the inner wall to the insulating layer, wherein the adhesive includes microballoons.
11 . The vehicle as recited in claim 1 further comprising an adhesive bonding the inner wall to the insulating layer, wherein the adhesive forms a sealing layer against the cryogenic fluid being carried by the tank.
12 . The vehicle as recited in claim 1 further comprising an adhesive bonding the inner wall to the insulating layer, wherein the adhesive is a cryogen-compatible urethane adhesive
13 . The vehicle as recited in claim 1 wherein the insulating layer has a modulus of elasticity lower than a modulus of elasticity of the inner wall.
14 . The vehicle as recited in claim 13 wherein the insulating layer has a modulus of elasticity lower than a modulus of elasticity of the outer wall.
15 . The vehicle as recited in claim 1 wherein the insulating layer has a thermal conductivity no greater than about 0.25 Watt/meter-° K.
16 . The vehicle as recited in claim 1 wherein the insulating layer comprises a foamed polymer.
17 . The vehicle as recited in claim 16 wherein the foam polymer comprises polymethacrylimide.
18 . The vehicle as recited in claim 1 wherein the insulating layer comprises a foam filled honeycomb structure.
19 . The vehicle as recited in claim 1 wherein the outer wall is a fiber reinforced structure.
20 . The vehicle as recited in claim 19 wherein the outer wall comprises fibers selected from the group consisting of glass, carbon and aramid fibers.
21 . The vehicle as recited in claim 1 wherein the outer wall is formed from a metallic material.
22 . The vehicle as recited in claim 1 further comprising an adhesive bonding the outer wall to the insulating layer, wherein the outer wall comprises a fiber-reinforced cyanate ester resin and wherein said adhesive comprises cyanate ester resin and glass microballoons.
23 . The vehicle as recited in claim 1 wherein said wall defines part of an outer structure of a flying vehicle.
24 . The vehicle as recited in claim 23 wherein said structure is a fuselage.
25 . The vehicle as recited in claim 1 further comprising a cryogenic fluid within the tank.
26 . The vehicle as recited in claim 1 further comprising a fluid within the tank, said fluid selected from the group of fluids consisting of liquid oxygen, hydrogen peroxide, liquid hydrogen, liquid methane and nitrous oxide.
27 . The vehicle as recited in claim 1 wherein the inner wall is chemically compatible with hydrogen peroxide.