Pipe-handling apparatus

#This invention relates to an apparatus, herein called a "coupler", which can be used for internally clamping, aligning, bringing together, and keeping together during welding, two lengths of pipe to be butt-welded, particularly but not exclusively those lengths of pipe which are subjected to longitudinal reciprocation with respect to each other, as can be experienced for instance during welding operations on board a pipe-laying barge.

#Such a device simplifies, speeds and makes cheaper the operation of welding a section of pipe, even if it has a great diameter, to a pipeline which has to be laid on the sea bottom.

#It is known that during the laying of a submarine pipeline the barge or other surface vessel used for the laying is moved stepwise forward in the longitudinal direction a distance approximately equal to the length of the pipe length to be added by means of welding to the existing pipeline to be laid and, after the forward movement, because of inertia, the laying barge goes beyond the equilibrium position which should be reached at the end of the movement, and the barge is subjected to an elastic force in the aft direction proportional to the difference between the forward pull and the aft pull of the mooring cables or chains connected to the drums of winches arranged on the laying barge. This elastic force is dependent on the maximum movement of the laying barge and on the depth of the sea on which the barge is working.

#For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

#FIGS. 1 to 6 show schematically a coupler according to the present invention, inside a pipeline, at subsequent stages during the cycle comprising (i) advancement of the coupler from the welded region between a pipeline and a pipe length, (ii) location of part of the coupler within a further pipe length to be joined to the pipeline, (iii) the securing of the coupler to the pipeline, (iv) the securing of the coupler to the further pipe length, and (v) the bringing together of the further pipe length and the pipeline; and

#FIG. 7 is a vertical, axial section, partly cut-away through a coupler according to the present invention located in a pipeline and in a pipe length to be joined to the pipeline.

#Referring firstly to FIG. 1, there is shown a pipeline 1 to be laid, to which a pipe length 3 is joined by means of a weld 2.

#The pipeline 1 is subjected to a reciprocating longitudinal movement in the directions indicated by the arrow 4, which obviously induces the same movement in the pipe length 3, as shown by the arrow 5. Bridging the pipeline 1 and the pipe length 3 is the coupler 6 which has a front portion 15 and a rear portion 16.

#The rear portion 16 is provided with two sets of radially disposed, hydraulically actuatable pressure pads 7 which can be projected radially or retracted radially, and with a set of driving wheels 9 and a set of guide wheels 10. The front portion 15 is provided with one similar set of radially disposed, hydraulically actuatable pressure pads 8 carried on an annular slider 18 mounted on, and slidable along an annular slide 17 which in turn is mounted on and slidable along an axial hollow shaft (indicated by the reference numeral 28 in FIG. 7). The slide 17 can be moved along the shaft 28 by, for example, a suitable hydraulic system; and the slider 18 can be moved along the slide 17, for example, by hand or by an electric motor.