Remotely controllable handling device for submerged structures, particularly for connecting underwater pipes

A remotely controlled undersea vehicle has a manipulator arm articulated to a mast which is articulated on the vehicle. Jaws at the end of the arm are arranged to close around a collar of a conduit having an automatic connector end, and to connect control fluid passages of the jaws to passages in the collar which communicate the control fluid to the automatic connector end.

The present invention relates to a device controllable from a distance from 
a surface support vessel for operating on submerged structures and 
connecting underwater pipes, notably flexible tubular pipes on or near the 
sea floor. 
With the recent development of submerged well heads for hydrocarbons there 
has been a very significant increase in the number of sub-marine 
connections to be made, and pipes to be manipulated at greater and greater 
depths. 
The actual techniques usually use undersea divers to carry out operations, 
notably connections, for example, between flexible tubular pipes which 
transport hydrocarbons, and well heads. 
Making a connection is usually done in three phases: first of all, the 
approach or bringing the conduit to the point of connection, then locking 
of ends in the receptacles provided for this purpose on the structures to 
be connected, and finally making the connection itself hydraulically or 
electrically. 
For the approach phase, it is often necessary to move the conduit a long 
distance which requires the use of heavy equipment, such as drags or skids 
for the ends of conduits, the movements of the ends of the conduits being 
initially from heavy surface supports capably of operating a string of 
rods like hoists used for drilling. The last phase, that is to say the 
connecting phase, is carried out either by divers or by means of hydraulic 
tools operated from the surface. 
The actual techniques thus usually require heavy and thus burdensome 
equipment, and also, most of the time, the intervention of divers, which 
because of the risks presented by the equipment, limits the intervention 
of divers. 
The present invention proposes to provide an apparatus to avoid these 
disadvantages recited above. 
The apparatus according to the invention is characterized essentially by 
the fact that it includes a driven vehicle mobile on the sea floor, 
connected to and controllable from a surface support, the vehicle 
comprising a frame on which are articulated two vertically spaced apart 
masts, at the ends of which are articulated manipulator arms each 
comprising a jaw at its end. 
The device according to the invention may be used to maneuver conduits, 
such as flexible tubular conduits resting on the sea floor, for example to 
displace them, the two manipulator arms permitting grasping at two places 
the conduit on the sea floor, to lift it and to displace it, and thus to 
manipulate it as desired. 
However, the preferred utilization of the device of the invention is in the 
field of the connection and disconnection of conduits, particularly 
flexible conduits, which have at least one automatic end connector. 
The combined use of the two arms, after having lifted and possibly 
displaced the conduit, permits, in this case, to position it with 
precision with respect to the structure to which it is to be connected. 
To assure such positioning, the arm most distant from the end of the 
conduit holds the conduit after having given it a determined orientation, 
while the arm nearest the conduit end provides fine movements to change 
the position of the end of the pipe so as to bring it exactly to the 
position of connection. 
Movements of this sort are permitted by the structure of the manipulator 
arms which each have, on the one hand, articulation in one or more, for 
example three degrees of freedom on the masts or posts connected to the 
frame, these upright posts each being attached on the other hand by an 
articulation with one or several, for example three degrees of freedom to 
the frame of the vehicle. 
In one particular embodiment, the tubular conduit is provided near its end, 
upstream of the automatic connector, with an external collar on which can 
be engaged the jaws of one of the manipulator arms, means being provided 
on the collar and on the fingers forming the jaws, to assure that while 
the jaw is attached and immobilized on the collar, there is transmission 
of control fluid between the jaw and the automatic end connector. 
These means may advantageously be constituted of normally closed valves 
disposed near the periphery of the collar, and whose opening, caused by 
the rods of the cylinders borne by the fingers of the jaw and when engaged 
in external opening of the collar assure communication of the control 
fluid between the jaw and the collar, the fluid passing then through the 
pipes provided for this purpose, from the collar toward the automatic 
connector. 
By opening thc fingers of the jaw and retracting the cylinder rods, the 
valves of the collar return to the normal closed position in which feeding 
of the control fluid to the connector is interrupted. 
It will of course be understood that disconnection (of the connector) is 
caused in the same manner after engagement of the corresponding jaw on the 
collar. 
The hydraulic cylinder contained in one or in each of the fingers of the 
jaw, comprises an enclosure or cylinder in which two chambers are defined 
by a pistion; each of the chambers can be independently supplied with 
control fluid, the piston being traversed by a hollow shaft attached to 
the piston and through the interior of which can circulate the fluid used 
to supply the automatic connector through the valves of the collar mounted 
on the conduit. 
The driven vehicle of the device according to the invention comprises 
advantageously, to support the frame on which are mounted the manipulator 
arms, four caterpillar tracks of independent articulation, each of the 
caterpillar tracks having a rolling track, for example of rubber plates 
stiffened by articulated crossbars. The two front caterpillar tracks, like 
the two rear caterpillar tracks, are nevertheless held rigid between 
themselves in such a manner as to stay parallel, regardless of their 
position during the advance of the vehicle. 
The device according to the invention is of course completed by a 
conventional navigation system, composed of means for examination 
orientation and observation permitting the detection of the objective, for 
example, a well head, and to position itself with respect to this for the 
purpose of carrying out the connection operations. 
At the same time the assembly operation is observed by a television system 
controlled by the operators based on the surface support vessel and this 
last can be a relatively light support vessel independent of the heavy 
production support. 
One observes that the device according to the invention does not need, 
contrary to the known devices, the presence of guidelines or any other 
mechanical surface-floor liason system permanently installed on the 
structures to be connected. The only liason between the device and the 
surface is carried out by use of a flexible service cable designed to move 
the fluids, particularly hydraulic control fluids, as well as to transmit 
information between the device and the surface support.

The device according to the invention comprises a drivable vehicle 1, 
mobile on the sea floor shown schematically at 2, and including 
essentially a frame 3, mounted on four caterpillar tracks 4. These 
caterpillar tracks are independently articulated, that is to say, each 
caterpillar track may take any position whatever with respect to the other 
caterpillar tracks as a function of the nature of the terrain, it being 
understood however that the two front caterpillar tracks as well as the 
two rear caterpillar tracks are attached so that they are always parallel 
with each other at the time of the movement of the vehicle. 
On the frame 3 are articulated upright masts or posts 5, one near the front 
end of the vehicle and the other near its back end. 
At the top end of each of the upright posts 5 is a manipulator arm 6, the 
connection between arm 6 and the corresponding upright post 5 is 
accomplished by means of an articulation 7 having one or several degrees 
of freedom. 
The forward end of each of the arms 6, bears a gripping mechanism having 
jaws 8. The upright posts 5 are articulated on the frame 3 by means of an 
articulation 9 with one or several degrees of freedom. 
Shown schematically on FIGS. 1 to 3 is a conduit, such as flexible tubular 
conduit 10, gripped by the jaws 8 of the device. 
Flexible tubular conduit 10, which is for example of the type of long 
length produced and sold by applicant's company, has at one end, for 
making connections, for example, at the head of a well (not shown) an 
automatic connector 11, shown schematically. 
Also shown on FIGS. 1 to 3 is the liason by means of supply line 12, which 
permits directing toward the vehicle 1, the necessary control fluids as 
well as directing to and from the surface information for operation. 
Certainly, the vehicle includes a navigation system, not shown, as well as 
visual control means such as cameras placed at different positions for 
visual supervision of the operations. 
Referring now to FIGS. 4 and 5 which illustrate the fluid supply to the 
jaws, that is from a surface support or from an intermediate reservoir 
carried by the vehicle to an automatic connector 11 shown schematically. 
The gripping mechanism with jaws shown as a whole at 8, includes two jaws 
13 pivotally mounted on pivots 14, the opening and closing maneuvers of 
these jaws being carried out by a cylinder 15, of which the rod 16 shown 
in extended position at FIG. 4, caused the closing of jaws 13 around a 
collar 17 attached to the tubular conduit 10 upstream from the automatic 
connector 11, this latter not being shown on FIG. 4 for better clarity. 
The pivot mechanism permitting the opening and closing of the jaws is 
itself conventional and will not be described in further detail here. 
Collar 17 includes a number of valves 18, four in number in the example 
shown. 
Each of the jaws 13 includes a piston 20 to which is attached a rod 21 
which, in the closed position of the jaws such as shown at the left on 
FIG. 4, traverses a peripheral orifice of the collar and manipulates the 
corresponding valve 18. 
Shaft 21 is traversed by conduit 22, supplied with control fluid, which in 
the open position of the valve 18 shown at the left on FIG. 4, flows to 
collar 17, via passage 30 and from there, by means of the ducts and pipes 
31 provided for this purpose, to the automatic connector 11 for the 
operations of connecting and disconnecting. 
For their operation, cylinders 19 include two supply ducts 23 and 24 for 
the control fluid, each opening into one of the chambers defined by piston 
20. 
The operation of the device according to the invention is as follows: 
After gripping a conduit to be connected in the jaws of the manipulator 
arms, the vehicle of the device according to the invention is moved close 
to the structure to which the connection is to be made. 
By relative displacements of the arms around their articulations, connector 
11 can be brought exactly into alignment with the position of the 
connector of the structure to be connected, for example, a well head. 
The automatic connector can then be activated by supplying it with control 
fluid from the jaws by feeding control fluid through duct 24 of each 
cylinder 19, so that rod 20 is displaced toward the front of the cylinder 
and operates the corresponding valves. 
Duct 22 of the rod is then supplied with control fluid to operate the 
automatic connector. 
After the connection is made, duct 23 is supplied with fluid, which causes 
the retraction of rod 21 of each cylinder, valves 18 returning to closed 
position by means of their return springs, 18 as for example shown for the 
valve on the lower part of FIGS. 4 and 5. Ports 32 communicate the inner 
ends of valves 18 with the undersea pressure so that the valves are 
hydrostatically balanced. 
The jaws are then released by the operation of cylinder 15 and the device 
can be used for other connections or for other operations of manipulation 
of the conduits. 
To perform disconnection, the same operations are done to bring the jaws to 
grip the collar, which allows the automatic connector to be supplied (with 
fluid) again. 
The collar shown comprises four valves regularly spaced around its 
periphery which permit the positioning of the jaws at different 
orientations around conduit 10. 
Although the invention has been described in reference to one particular 
embodiment, it is evident that it is in no way limited, and that numerous 
modifications can be made without departing either from its scope or its 
spirit.