Abstract: A method for joining fluid carrying steel pipes together including the following steps. Identifying a subject pipe section to be replaced and intercepting the fluid flow by fastening stoppers inside of pipe portions upstream and downstream from the subject pipe section. Removing the subject pipe section, leaving in place upstream and downstream pipe portions. Inserting along each of the first and second pipe portions a protective stopper and chamfering the edges of those pipe portions and then mounting first and second sliding sleeves with sealing rings thereover. Removing the protective stoppers from the pipe portions and positioning between those pipe portions a new connection piece. Displacing the first and second sliding sleeves onto the connection piece so that sealing rings are arranged on the connection piece and fixing the sliding sleeves to the pipe portions and to the connection piece.

Abstract: Method for joining together steel pipes for conveying fluids under pressure, characterized by the following steps: a) identifying a pipe section to be replaced and intercepting, by means of the creation of suitable points for fastening stopper systems, the fluid flow inside the pipe upstream and downstream of this pipe section; b) after the fluid flow has been intercepted, removing the pipe section to be replaced so as to obtain upstream and downstream thereof two pipe sections; c) inserting along each pipe section protective stopper means, chamfering the edges of the sections and then mounting a sliding sleeve provided with sealing means; d) removing the protective stoppers from the pipe sections and positioning between them a new connection piece, such as a pipe section, a branch-off piece, a valve or the like; e) displacing the sliding sleeves on these pipe sections so that the sealing means are arranged on the new connection piece; f) fixing these sliding sleeves to these pipe sections and to this connect