| 摘要 |
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 DEG 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.
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