Abstract: A device for temporarily shutting off conduits comprises an elastic or resilient sleeve expansible under powerful internal pressure, and having a rubber wall comprising at least two superimposed plies defining an internal tube and an external sheath, the cords of all the plies being crossed from one ply to another while forming angles smaller than 30.degree. with respect to the generatrices.According to the invention, the pair of outer plies constitutes a resistant carcass of the sleeve while the pair of internal plies form protective plies constituted by adjacent cords having a diameter less than half that of the cords of the outer plies of the carcass and forming with the generatrices angles not greater than the angles of the cords of the carcass plies.

Abstract: A self-floating flexible pipe for use with off-shore petroleum installations, which includes an inner reinforced pipe for conducting fluids which is surrounded by a layer of cellular material for assuring permanent floatation of the pipe. In order to protect the cellular layer, an outer reinforcing sheathing formed of helically wound metallic cables embedded in a rubber layer is provided. These helically wound metallic cables are wound at a setting angle with respect to the longitudinal axis of the pipe in the range of 56.degree. to 68.degree. so as to minimize the effect of these armoring cables on the flexibility of the overall pipe construction. These armoring cables are also preferably resilient in a longitudinal direction, with preferred embodiments including undulated cables so as to further lessen the impact of these cables on the flexibility of the pipe. An outer covering layer of polychloroprene is provided on the rubber layer within which the cables are embedded for protecting this rubber layer.