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US 3,993,213 AGranted
Thermally insulated cryogenic container
AssigneeMcDonnell Douglas Corporation
InventorsGeorge W. Burge, Richard A. Madsen
Life of this patent
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AssigneeMcDonnell Douglas Corporation
InventorsGeorge W. Burge, Richard A. Madsen
Estimating the term…
Thermally insulated container or tank wall construction for cryogenic fluids such as liquid natural gas (LNG) comprising at least two layers of an insulation material, preferably a fiberglass reinforced urethane foam, having an inner liner, preferably in the form of an aluminum foil-fiberglass cloth combination, in contact with the cryogenic fluid, the inner liner being perforated to permit rapid venting, and a thermal stabilizing barrier or liner between the layers of insulation, the stabilizing barrier also preferably being formed of a combination of fiberglass cloth with a layer of aluminum foil to reduce permeability. The two liners are bonded to the individual layers of insulation and the insulation is in turn bonded to the container or tank wall by a suitable adhesive such as a polyurethane adhesive. In the design of such system, the low permeability thermal stabilization barrier is placed a distance from the cold insulation face adjacent the inner liner equal to or greater than a distance at which boiling will be established adjacent the thermal stabilizing barrier, thereby building up a thin gas layer adjacent to such barrier and preventing liquid from contacting and penetrating the stabilizing barrier.
A thermally insulated container for low-temperature or cryogenic fluids, including liquid natural gas, which comprises an outer container having an outer wall, at least two layers of insulation material supported within said container, including an outer insulation layer and an inner insulation layer, an inner liquid liner disposed adjacent said inner layer, said liner being in contact with said low-temperature fluid, said inner insulation material being fluid permeable, and a stabilizing barrier of low fluid permeability disposed between said at least two layers of insulation material, said outer stabilizing barrier being positioned at a predetermined distance from the cold face of said inner liner, such that boiling of fluid permeating said inner insulation layer occurs therein adjacent said stabilizing barrier and forming a stable gas layer in said inner insulation layer adjacent said stabilizing barrier, thereby substantially preventing low-temperature liquid from contacting and penetrating said barrier, said predetermined distance being slightly larger than the penetration depth of a stable liquid film of said cryogenic fluid through said inner liner and into said inner insulation layer, said predetermined distance of said stabilizing barrier from the cold face of said inner liner being dependent upon the type of said low-temperature or cryogenic fluid, the head of said fluid in said container, the temperature of the outer wall of said container and the permeability of said stabilizing barrier.
An improved thermally insulated container for low-temperature or cryogenic fluids, including liquid natural gas, which comprises an outer container having an outer wall, a first outer insulation layer of closed cell polyurethane foam supported on the inside surface of said outer container, a second inner insulation layer of closed cell polyurethane foam peripherally disposed adjacent to and around the inner surface of said first insulation layer, an inner liquid liner positioned around and in contact with said second inner insulation layer, said inner liner comprised of a combination of a fiberglass cloth and aluminum foil, said aluminum foil being in contact with said low-temperature fluid in said container and said fiberglass cloth being in contact with said inner insulation layer, said inner liner being perforated with a plurality of holes, rendering said inner liner fluid permeable, and a stabilizing barrier positioned between and in contact with said outer and inner insulation layers, said stabilizing barrier comprised of a combination of aluminum foil and fiberglass cloth, said stabilizing barrier having reduced permeability, said last mentioned aluminum foil being in contact with said inner insulation material and said last mentioned fiberglass cloth being in contact with said outer insulation material, said stabilizing barrier being positioned at a predetermined distance from the inner surface of the aluminum foil of said inner liner such that boiling of fluid permeating said inner insulation layer occurs therein adjacent said aluminum foil of said stabilizing barrier and forming a stable gas layer in said inner insulation layer adjacent said aluminum foil of said stabilizing barrier, thereby essentially preventing low-temperature liquid from contacting and penetrating said stabilizing barrier, said predetermined distance being slightly larger than the penetration depth of a stable liquid film of said cryogenic fluid through said inner liner and into said inner insulation layer, said predetermined distance of said stabilizing barrier from the cold face of said inner liner being dependent upon the type of said low-temperature or cryogenic fluid, the head of said fluid in said container, the temperature of the outer wall of said outer container and the permeability of said stabilizing barrier.
Dependencies are inferred from the claim text.