Abstract: An internal mandrel (22) cooperating in the operation of joining two successive lengths of tubing by welding, and it is characterized in that this mandrel comprises zones (25, 26, 27) separated longitudinally and serving respectively for matching, welding, and welding checking, and means of displacement of the mandrel (22) by a step, enabling the latter to present the said zones in succession in front of one and the same working station.

Abstract: The present invention relates to a heavy-duty metal brush particularly, but not exclusively, for removing anti-corrosion materials from an immersed metal surface.The brush comprises a compact assembly of radial strands of, for example, steel wire, which are applied against each other and are clamped between two metal plates, the diameter of which is less than that of the assembly of strands by at most 20 mm.In use of such a brush for removing an anticorrosion covering, the brush may be rotated at a circumferential speed of the order of 17 meters per second and may be mounted on a carriage adapted to roll over the surface on rollers and which is displaced either automatically or manually.

Abstract: A process for tapping a region of a pipe placed on a sea bed utilizes a working platform which is installed vertically above the region of the pipe to be tapped, the platform being adapted to receive a support girder which can be lowered from the surface of the sea onto the working platform and be engaged therewith and then lifted off the platform. The platform is adapted to receive successively a plurality of modular tool-carriers provided with tools for carrying out a variety of operations on the pipe, the operations including concrete stripping, removal of anti-corrosion covering, transverse cutting, internal brushing, and making the longitudinal weld flush.

Abstract: The invention concerns the removal of a concrete covering applied to an underlying surface provided with an anti-corrosion coating, for example that of a hydrocarbon-conveying pipe.The coating is removed by making trenches in the concrete to divide it into removable elements, the trenches being made using a cylindrical milling cutter having a longitudinal diamond-faced toothing and provided with a central stud of tungsten carbide projecting axially from the end of the cutter. In use the stud contacts the surface to prevent the surface being damaged by the toothing on the cutter as the cutter is moved transversely across the surface. To initiate a concrete covering removal operation, a hole is first drilled through the covering perpendicular to the surface for receiving the stud. The cutter is then moved perpendicularly to the surface through the concrete with the stud projecting into the drilled hole and until the stud contacts the surface.

Abstract: An electron beam welding chamber for butt joining elongate members 1,2 extending longitudinally at the center of the chamber. The chamber comprises an envelope 7 defining the welding enclosure 6 and which rests on a fixed structure 8. The electron gun equipment 13 is provided within the envelope and is mechanically connected, by a withdrawable connection means 18 or by elastic connection means 24, 25, to the enclosure, clamping means 15 being provided for clamping the electron gun equipment relative to one of the elongate members. This invention is particularly applicable to the welding of the sections of a pipe to be laid on the sea bed.

Abstract: A welding chamber in which a vacuum is created for welding, using an electron beam, elongate pieces extending centrally of the chamber. The welding chamber is divided into a central sub-enclosure 41 for receiving the pieces 1, 2 to be welded and which is evacuated during welding, and a peripheral sub-enclosure 42 in which the welding means are located and which is permanently evacuated, the two sub-enclosures being separated by retractable sealing gaskets 12, 26, 27 which are retracted during welding to place the two sub-enclosures in communication.