Abstract: A mobile arrangement for laying a continuous pipeline comprises a resistance welding apparatus, an outer flash trimmer, and at least one pipe-laying means. A jib of the pipe-laying means has a longitudinal support structure suspended therefrom. A suspension is attached to this longitudinal support structure. The front end of said longitudinal support structure carries an outer flash trimmer, and the rear end of said longitudinal support structure carries an inductor for thermal treatment of the weld.

Abstract: In a resistance welding apparatus of a detachable grip type an improvement consists in that each pipe grip has a bracket (16) whereon two double-arm levers (18), one per side member (3), are pivoted. Similar arms of each lever (18) are interconnected by an extension spring (19), while the other arms are operatively associated with swinging jaws (14) adapted to abut against the pipe surface in their operating position. Each side member (3) is provided with a stop (21) for limiting the movement of the levers (18) relative the corresponding side member (3) in the direction of the action of the extension spring (19).

Abstract: A method and apparatus for welding girth joints in pipelines using two welding heads comprises the steps of moving each of the welding heads upwards around the pipeline along the respective section of the girth joint, feeding a welding wire to each of the welding heads so that the welding wire is fed substantially tangentially with respect to the surface of the pipe, and forming a circumferential weld by moulding it to hold the molten metal of the welding bath in the welding zone. An apparatus for carrying out the method for welding girth joints in pipelines comprises an annular track structure having at least two carriages mounted thereon which are connected with drives adapted to impart a translatory motion to the carriages. Each of the carriages carries a welding head provided with a welding wire feeder and a weld moulding member arranged opposite to the joint being welded.

Abstract: A welder arranged inside pipes to be welded comprises a housing with the longitudinal axis thereof matched with the axis of the pipes. On the housing are a welding transformer and two mechanisms clamping the pipes, each having a drive moving the mechanism along the axis of the housing, and each being electrically connected to the transformer. The housing has mounted thereon a pipe flashing and upsetting mechanism with its own hydraulic drive, kinematically coupled to one of the pipe clamping mechanisms, a hydraulic pump supplying fluid to the drives, and a mechanism driving the welder along the pipes' axis. The housing carries two bearing discs secured at opposite ends and three clips mounted on roller supports and movable along the housing's axis. Two clips are incorporated in the first and second clamping mechanisms, respectively, and the third is part of the flashing and upsetting mechanism.