Patent ID: 8616246

Claim:
A method of preparing an insulated pipe-in-pipe assembly, which method comprises: (i) providing an assembly comprising: (a) at least one inner pipe, (b) an outer pipe that is positioned around the at least one inner pipe so as to create an annular space between the exterior surface of the at least one inner pipe and the interior surface of the outer pipe, and (c) at least two containers comprising porous, resilient, volumetrically compressible material consisting of porous particles, wherein the compressible material is restrained within the containers and have a first volume, wherein the first volume of the compressible material is less than the unrestrained volume of the compressible material, and wherein the at least two containers are disposed in the annular space; and (ii) altering the at least two containers to reduce the restraint on the compressible material to increase the volume of the compressible material to a second volume that is greater than the first volume, thereby forming an insulated pipe-in-pipe assembly.