An insulating insert is positioned around a field joint of a pipeline to insulate the field joint. The insert has a longitudinal series of annular or part-annular filler segments of insulating material, curved about a longitudinal axis, that are each joined to one or more adjacent segments of the series by at least one link. The links may be webs, rods, or articulated links. The links are flexible relative to the segments to facilitate bending of the insert along its length by enabling relative angular displacement between adjacent segments of the series.

An insulating insert is positioned around a field joint of a pipeline to insulate the field joint. The insert has a longitudinal series of annular or part-annular filler segments of insulating material, curved about a longitudinal axis, that are each joined to one or more adjacent segments of the series by at least one link. The links may be webs, rods, or articulated links. The links are flexible relative to the segments to facilitate bending of the insert along its length by enabling relative angular displacement between adjacent segments of the series.

A method protects a field joint of a pipeline, where chamfered edges of thermally-insulating parent coatings on conjoined pipe lengths are in mutual opposition about a longitudinally-extending gap. The method includes manufacturing an hourglass-shaped inner layer around the pipe lengths, which layer may be moulded. The inner layer extends longitudinally along the gap between the chamfered edges and at least partially overlies the chamfered edges. A thermally-insulating solid insert is assembled from two or more parts to lie in the gap surrounding the inner layer, and pressure is applied radially inwardly from the insert to the inner layer. An outer layer of molten material is manufactured around the insert to form a watertight barrier and to form one or more melted interfaces with the inner layer. Corresponding field joint arrangements are also disclosed.

A method protects a field joint of a pipeline, where chamfered edges of thermally-insulating parent coatings on conjoined pipe lengths are in mutual opposition about a longitudinally-extending gap. The method includes manufacturing an hourglass-shaped inner layer around the pipe lengths, which layer may be moulded. The inner layer extends longitudinally along the gap between the chamfered edges and at least partially overlies the chamfered edges. A thermally-insulating solid insert is assembled from two or more parts to lie in the gap surrounding the inner layer, and pressure is applied radially inwardly from the insert to the inner layer. An outer layer of molten material is manufactured around the insert to form a watertight barrier and to form one or more melted interfaces with the inner layer. Corresponding field joint arrangements are also disclosed.

A fluid conduit that is below grade or under water is separated from ambient water by a confined layer of liquid that may be largely undivided by solids. The separation distance between the liquid containment means and the piping or pipeline is such that the total heat transfer by natural convection and conduction from the piping or pipeline to the water containing environment is kept within limits thought necessary to adequately insulate the contents of the pipeline. A liquid may be pumped between the pipe and the means for containing the insulation so as to displace fluids from a pipeline or a heated liquid may be pumped through that space to warm the contents of the pipeline. If the insulating liquid also electrically insulates the pipe, then the pipe may be heated by passing a current directly through the pipe.

A fluid conduit that is below grade or under water is separated from ambient water by a confined layer of liquid that may be largely undivided by solids. The separation distance between the liquid containment means and the piping or pipeline is such that the total heat transfer by natural convection and conduction from the piping or pipeline to the water containing environment is kept within limits thought necessary to adequately insulate the contents of the pipeline. A liquid may be pumped between the pipe and the means for containing the insulation so as to displace fluids from a pipeline or a heated liquid may be pumped through that space to warm the contents of the pipeline. If the insulating liquid also electrically insulates the pipe, then the pipe may be heated by passing a current directly through the pipe.

An applicator machine and a process for heating and coating a section of pipeline. The applicator machine includes a frame configured to rotate about a section of pipeline to be heated and coated, rotating means operable to rotate the frame, and coating material applicators induction coils and radiant heaters mounted on the frame and rotatable therewith. The induction coil is configured to heat a section of pipeline adjacent to the induction coil to a coating material application temperature. The radiant heaters are configured to heat factory-applied coatings. Each coating material applicator sprays coating material through an aperture in a respective induction coil. The applicator includes an enclosure configured to surround a section of pipeline and provision for evacuating and collecting waste coating material. The coating material applicator may be configured to spray powder coating material, such as fusion bonded epoxy powder material and/or chemically modified polypropylene powder material.

An applicator machine and a process for heating and coating a section of pipeline. The applicator machine includes a frame configured to rotate about a section of pipeline to be heated and coated, rotating means operable to rotate the frame, and coating material applicators induction coils and radiant heaters mounted on the frame and rotatable therewith. The induction coil is configured to heat a section of pipeline adjacent to the induction coil to a coating material application temperature. The radiant heaters are configured to heat factory-applied coatings. Each coating material applicator sprays coating material through an aperture in a respective induction coil. The applicator includes an enclosure configured to surround a section of pipeline and provision for evacuating and collecting waste coating material. The coating material applicator may be configured to spray powder coating material, such as fusion bonded epoxy powder material and/or chemically modified polypropylene powder material.

A method of coating a field joint of a pipeline places at least one body having a thermoplastics material around the field joint. The body is heated in a mold cavity around the field joint to effect thermal expansion of the thermoplastics material. Thermal expansion of the body in the mold cavity is constrained to apply elevated pressure between the body and pipe sections joined at the field joint. The elevated pressure improves bonding and fusing between the body, which forms a field joint coating, and the parent coatings and the exposed pipe sections of the pipe joints. The body need not be fully molten, which reduces the mold residence time including in-mold heating and cooling phases.

A method of coating a field joint of a pipeline places at least one body having a thermoplastics material around the field joint. The body is heated in a mold cavity around the field joint to effect thermal expansion of the thermoplastics material. Thermal expansion of the body in the mold cavity is constrained to apply elevated pressure between the body and pipe sections joined at the field joint. The elevated pressure improves bonding and fusing between the body, which forms a field joint coating, and the parent coatings and the exposed pipe sections of the pipe joints. The body need not be fully molten, which reduces the mold residence time including in-mold heating and cooling phases.