Device for welding inside a tube of small diameter

DETAILED DESCRIPTION An object of the invention is therefore to provide an orbital welding device inside a tube of small diameter, in particular inside a steam generator tube crimped at one of its ends into a tube plate of great thickness, consisting of a welding head with a diameter smaller than the internal diameter of the tube, comprising a carrier, to which a guiding component and a radially directed electrode are fastened, which is fastened to the end of a flexible tubing and by means for moving the welding head in axial translation in the tube and in rotation about the tube axis, this device permitting welding operations to be carried out at any height in the steam generator tube, in regions far from the tube plate and, optionally, in the region of the various spacers retaining the bundle and arranged in locations spaced at regular intervals along the height of the bundle.
To this end, the driving means for rotating the welding head is arranged in a motor casing inserted between two sections of the flexible tubing, one of these sections connecting the casing to a bush in which the welding head is mounted so that it can rotate, and comprising a flexible component for transmitting the rotary motion between the driving means and the welding head, and the other section being connected at one of its ends to the motor casing and coupled with a puller-pusher device for moving the flexible tubing and thereby the welding head and the motor casing.