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US 4,464,082 AGranted
Chilled gas pipeline installation and method
AssigneeNorthwest Alaskan Pipeline Company
InventorRalph M. Isaacs
Life of this patent
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AssigneeNorthwest Alaskan Pipeline Company
InventorRalph M. Isaacs
Estimating the term…
A chilled-gas carrying pipeline installation in soil or rock zones with different heave properties is disclosed which includes an earth-covered buried steel pipe with insulation formed of high strength urethane or other material covering substantially the upper 300 peripheral degrees of the buried pipe; the bottom of the pipe is bare of insulation so that the insulation means provides sufficient resistance to heat flow from the earth above the pipe into the pipe to permit the earth above the pipe to thaw from the surface down to about the horizontal diameter of the pipe during the warm season. The buried pipe is consequently substantially unrestrained against upward movement caused by freezing of the soil in active areas beneath the pipe so that the pipe is subjected to minimum strain or relieves substantially any strain accumulated during the previous cold season.
A chilled media carrying pipeline installation comprising an earth-covered buried pipe member and insulation means covering the upper half and a portion of the lower half of the buried pipe member, the lowermost bottom portion of the buried pipe member being bare of insulation means, and wherein the insulation means provides sufficient resistance to heat flow from the earth above the pipe into the pipe to permit the earth above the insulation means to thaw from the surface down to the insulation means during periods of warm weather while chilled media flowing through said buried pipe member maintains the area immediately beneath the pipe in a permanently frozen condition.
In a pipeline containing chilled gas extending across a frost heave intensive zone and adjacent zones having less frost heave, the improvement comprising insulation means covering the upper portion of the pipe for substantially inhibiting the transfer of heat through the upper portion of the pipe from a covering of soil overlying the thermal insulation means to reduce frost heave resisting forces in the adjacent zones by permitting the thawing of the covering soil in said adjacent zones during the summer months.
A method of minimizing strain on an earth-covered buried chilled gas pipeline extending through adjacent soil or rock zones having different frost heave characteristics, said method comprising the steps of:
Dependencies are inferred from the claim text.