markfoerlagd roerledning foer chilled medium and saett to reduce roerledningens formfoeraendring at tjaelbildning

摘要

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.