Abstract: A telescopic joint for repairing underwater pipelines laid at a great depth in which an annular sheath of steel having a yield point of not more than one half that of an outer sleeve of the joint is welded onto an inner cylinder, to create with the inner cylinder an annular chamber or interspace, the cylinder-sheath-sleeve assembly being guided in its telescopic movement by an inner tube welded coaxially to an end of the outer sleeve. The interspace is connected to an oil pump which under adequate pressure can cause the steel sheath to expand, to the extent that it yields, to interlock with the outer sleeve.

Abstract: Method for tightly jointing a sleeve to a submarine pipe laid on a very deep sea-bottom, characterized by the preliminary stages of providing a series of grooves on the inside surface of the sleeve, and of filling each one of said grooves with two half-rings made of a material collapsible under high pressures up to a 70% variation of its volume. A type of such a material is moreover described.

Abstract: A seal system for a spherical joint in which the metal seal ring is sandwiched coaxially between two wedge-shaped metal compression rings which are inserted into corresponding cavities in the front surfaces of the seal ring and are pressed against a metal stop ring by a series of flat springs which become preloaded as a result of forcing the female part of the joint onto the male part.

Abstract: A pliable metallic joint for underwater pipelines laid at great depths, having a bellows-like section of a pliable metal or alloy, which is externally reinforced by a sturdy metal wire coiling positioned in the grooves of said bellows and which is internally reinforced by interlockingly arranged U-shaped rings and an axial undulated circular spring that allow a high degree of deformation and facilitate joining two pipes.

Abstract: A method for connecting in a sealtight manner a flanged sleeve to a pipe, especially for subsea gas and oil ducts, comprises the steps of introducing the free end of the pipe into the flanged sleeve with a clearance, expanding the pipe within the sleeve with the aid of a resilient expansible body which is axially compressed, releasing the axial compression and withdrawing the expansible body. The radial expansion is such as to expand the pipe at its plastic deformation condition and the sleeve within its elastic deformation limit, so that a union is achieved between the tube and the sleeve which is virtually indissoluble.