The invention provides a method of connecting together two unit elements (4, 4) of a fluid transport pipe, each unit pipe element being made of metal alloy and being covered in an outer insulating coating (6, 6) made of a thermoplastic material, with the exception of an end portion that does not have an outer insulating coating, the method comprising a step of butt-welding together two unit pipe elements at their end portions having no outer insulating coating, a step of mechanically assembling at least two rigid shells (14, 16) made of a thermoplastic material on the end portions of the unit pipe elements not having an outer insulating coating, and a step of keeping the shells sealed against the outer insulating coating of the two unit pipe elements.

A pipe joint coating for welded ends of pipes forming a pipeline. A last and third layer of a 3LPP coating system covering at least a circumferential weld area of the pipe joint is a heated sheet applied around the pipe with a machine including a mounting frame and a transport carriage rotatably movable on the mounting frame to move circumferentially about the pipe joint, and a roller applying an adjusted pressure to the sheet against the pipe and adapting to eccentricity or ovality of the pipe. The sheet is pressed below the pipe away from its overlapping ends, a first part of the sheet is then applied when the roller is rolled in a first direction, and a second part of the sheet is applied by the roller rolled back in the reverse direction around the pipe. The sheet is dimensioned to obtain an overlapped area between its extremities.

A heat-shrink sleeve is provided for covering a pipe joint formed between two pipes that are coupled to one another to form a tube. The heat-shrink sleeve includes a heat-shrinkable material that is configured to conform to the first and second pipes when heated to cover the pipe joint.

A wrap tape cassette for a subsea pipeline repair or coating machine includes a drum for carrying a wrap tape wound on the drum. A housing defines an exit opening for the wrap tape to be dispensed from the drum onto a pipeline during a repair or coating operation. The drum may be mounted to the housing for rotational and longitudinal movement relative to the housing to dispense the wrap tape through the exit opening on being unwound from the drum. A leading end of the wrap tape may be attached to an anchor element that is arranged as a closure for the exit opening and, when moved from the exit opening, for attachment to a pipeline being repaired or coated.

A method of protecting a layered coating on a length of pipe for subsea use includes applying an edge finisher to the coating to encase an edge of the coating by fusing the edge finisher with the coating or by moulding the edge finisher at an edge of the coating. Where the coating and the edge finisher are of thermoplastics such as PP, fusing can be achieved by injection moulding the edge finisher or by welding a discrete edge finisher component to the edge of the coating. Mirror welding may be employed for this purpose, with a hot plate being interposed between the edge of the coating and the edge finisher.

The present invention relates to a pipeline junction coating between the joined ends of two coated metallic pipeline sections, the coating comprising an elongate body able to extend over the joined ends of the coated pipeline sections, and having a variable end profile at one or both ends. The pipeline junction coating is for coating field joints of coated rigid pipelines, as used in the subsea oil and gas industry.

Extrudable compositions were prepared comprising poly(propylene) and a liquid additive comprising a lactam group. The compositions can comprise other optional additives that include a polyhemiaminal, antioxidants, UV light absorbers, and surfactants. The extruded compositions have higher percent elongation at break and lower Young's modulus compared to extruded poly(propylene) lacking the liquid additive. These and other property improvements make the extruded compositions attractive for forming field joint coatings for undersea pipeline applications.

A pipe-joining method for building a hydrocarbon pipeline, in particular an underwater pipeline, includes welding two adjacent pipes to form a cutback, and forming a protective coating about the cutback. Forming the protective coating includes applying an LE (liquid epoxy) resin or a powdered FBE (fusion bonded epoxy) resin to the cutback to form a primer coat; and applying a powdered polypropylene adhesive on top of the still-wet primer coat to form an auxiliary adhesive coat. Forming the protective coating also includes fitting a polypropylene heat-shrink sleeve around the auxiliary adhesive coat; and heating the sleeve to shrink and bond the sleeve to the auxiliary adhesive coat.

The invention relates to pipe heat insulation and in particular to methods of heat insulation installation on welded joints of subterranean pipes for transporting oil and oil products. The method includes applying an anticorrosive layer on the welded joint using heat-shrinkable polymeric tape, mounting heat insulating polyurethane foam pipe coverings on the tape, using tie straps with locks to secure the pipe coverings, gluing hot-melt adhesive tape at the edges of a pipe protective envelope to overlap the envelope and the pipe coverings, installing a metal casing symmetrically relative to the center of the weld joint, and sealing the metal casing and the envelope with a heat-shrinkable polymeric fabric. The technical result provides anticorrosive protection and heat insulation of the welded joint of steel pipelines, provides improved heat insulation installation on the pipeline, and reduces the cost of installation and labor intensity.

An injection molding apparatus has a mold tool that is positioned around a field joint of a pipeline to define a mold cavity. Two or more pumping chambers communicate with the mold tool. Each chamber is expansible to draw in molten polymer and contractible to drive the polymer into the mold cavity. Expansion of one chamber is synchronized with contraction of another chamber. The operation of supply and injection valves associated with the chambers is also synchronized, both with each other and with expansion and contraction of the chambers. In the embodiment described, two pumping chambers are defined within a common pressurizing cylinder, in which the chambers are separated by a piston. The piston is movable within the cylinder to determine and to synchronize expansion and contraction of the chambers.