A gas tank liner comprises: a cylindrical section formed using a first resin; and a dome section formed using a second resin, the dome section being arranged at each axially opposite end of the cylindrical section, wherein either one of the first resin or the second resin has a higher linear expansion coefficient and higher yield strain than the other, the yield strain being the threshold of strain that, when met, makes the first resin or the second resin incapable of restoring its original state if the first resin or the second resin strains and yields in response to the application of external force.

The method to radially displace liquid liner inside a pipe includes the step of flowing the liner around a distributive body placed within a pipe gas stream. As the gas streams past the distributive body, the liner coats the pipe homogeneously from top to bottom.

This invention offers a method to install a wear-resistant polymeric sleeve in a pipe bend stiffener with a metal inner wall, including the following steps: calculate thickness of the internal wall of the stiffener that can removed; remove the thickness of at least a portion of the calculated inner wall; and apply a polymeric material sleeve in the inner wall of the stiffener, where the polymeric material sleeve has the thickness of the inner wall removed.

This invention offers a method to install a wear-resistant polymeric sleeve in a pipe bend stiffener with a metal inner wall, including the following steps: calculate thickness of the internal wall of the stiffener that can removed; remove the thickness of at least a portion of the calculated inner wall; and apply a polymeric material sleeve in the inner wall of the stiffener, where the polymeric material sleeve has the thickness of the inner wall removed.

A method of manufacturing a vent for a pipeline liner comprises overmoulding a porous element in a polymer body. This produces a vent in which the element extends across, and is in fluid communication with, a through-passage formed in the body during overmoulding. The element is supported in a mould cavity clamped between opposed internal mould formations that define at least part of the through-passage. The integrity of the vent and of the interface between the vent and the liner is maintained during die-drawing of the liner. Thus, the porous element is mechanically engaged with the surrounding body as flowable material of the body is absorbed into the element during overmoulding. Internal flanges also restrain the element against movement along the through-passage. The vent is also fused with the liner by heating interface regions to a softening or melting temperature before inserting the vent into a wall of the liner.

A method of manufacturing a vent for a pipeline liner comprises overmoulding a porous element in a polymer body. This produces a vent in which the element extends across, and is in fluid communication with, a through-passage formed in the body during overmoulding. The element is supported in a mould cavity clamped between opposed internal mould formations that define at least part of the through-passage. The integrity of the vent and of the interface between the vent and the liner is maintained during die-drawing of the liner. Thus, the porous element is mechanically engaged with the surrounding body as flowable material of the body is absorbed into the element during overmoulding. Internal flanges also restrain the element against movement along the through-passage. The vent is also fused with the liner by heating interface regions to a softening or melting temperature before inserting the vent into a wall of the liner.