EP0139596A2 - Device for working at under-water structures having several branches - Google Patents

Abstract

The device is particularly suitable for cleaning and inspecting the nodes of an underwater structure having several branches 1, 2, 3, 4. The device comprises an annular support formed by two rings (5) connected by cross-pieces (6) and capable of being positioned around one branch of the structure. It also comprises, on the annular support, a mobile carriage (7) which carries a tubular component (8) supporting a mobile tool-holding arm (9), extending along at least one direction parallel to the axis of the annular support. A tool support (10), on which a tool (11) is mounted, is attached to the end of the arm (9) so that it can swivel. <IMAGE>

Description

The present invention relates to a device for performing work on a structure with several branches and more particularly a device for cleaning the nodes of a drilling rig at sea.

There are currently many large tubular structures. In particular, there are very many oil drilling platforms built around the world in an assembly of tubular steel branches welded together. The junction of these tubular branches forms more or less complex nodes which work in fatigue regime when the structure is subjected to the action of the sea.

It is therefore necessary to carry out periodic monitoring of the nodes and more particularly of the nodes which are in regions of stress concentration.

In addition, structures of this kind are generally subject to significant pollution, in particular, in the case of underwater platforms, the pollution occurs either in the form of plant pollution such as algae or other various vegetation. 'or in the form of animal pollution resulting most of the time by the presence of limestone concretions which strongly adhere to the walls.

• - une observation visuelle ou au moyen d'un instrument (caméra vidéo),
• - une opération de nettoyage en vue de contrôles non destructifs,
• - les opérations de contrôle elles-mêmes.

As a result, monitoring a node usually involves three phases:

• - visual observation or by means of an instrument (video camera),
• - a cleaning operation for non-destructive checks,
• - the control operations themselves.

Currently, in the case of an underwater platform, almost all of these operations are carried out by divers, with the exception sometimes of observation work which is carried out using remote-controlled vehicles.

As soon as the depth exceeds a few tens of meters, these operations by divers become extremely expensive. This is why we are now looking to replace more and more divers not only in observation operations but also in cleaning and non-destructive testing operations.

Cleaning is currently the most expensive of these three operations, it is on it that must focus first the efforts of automation or, at least, remote-controlled work without plunger. Preferably, the device envisaged must also make it possible to carry out work other than cleaning work.

The use of a remote-controlled device comprising an articulated arm is not satisfactory in the sense that 1-a curve formed in space by the junction of two branches of structure of different diameters and at an angle which can be variable according to the node of the structure considered, is a complex mathematical curve. This curve is all the more difficult to follow as the guided submarines generally have to move and keep a substantially horizontal attitude. means of propulsion badly allowing them to tilt relative to the horizontal plane.

It is known from document GB 2.027.473 A to produce a device for performing work on an underwater structure with several branches comprising an annular support articulated so as to be locked around one of the branches of the structure, a carriage mounted on the annular support and movable in a transverse direction relative to the axis of the annular support and a tool support rigidly attached to the carriage. Because of this rigid attachment, the tool support cannot adapt to the complexed curve of the knot between two branches and this device can therefore only be used on the linear part of a branch.

In addition, the device envisaged must be of weight, size and energy consumption compatible with the use of an underwater vehicle, possibly manned, but preferably remotely controlled.

An object of the present invention is therefore to propose a device which is capable of carrying and implementing successively several tools in the vicinity of the nodes of an underwater structure with several branches without direct intervention on the place of use.

With a view to achieving this goal, a device is provided for performing work on an underwater structure with several branches comprising an annular support articulated so as to be able to be locked from one of the branches of the structure, a carriage mounted on the annular and movable support in a transverse direction relative to the axis of the annular support, a means for driving the carriage along the support, means for supplying energy to a tool and accessories of the tool, and an arm adapted to support the tool and its accessories and supported by the carriage, in which the arm is movable in at least one direction substantially parallel to the axis of the annular support, and is connected to a drive means of the arm relative to the carriage.

Thus, during the movement of the carriage on the annular support, the arm moves along the axis of the branch of the underwater structure and the work on the node is correctly executed.

According to other features of the invention, the tool-carrying arm comprises at one end an articulated parallelogram, two articulations of which are mounted spaced apart at the end of the tool-carrying arm, while the other two articulations are mounted so spaced apart on a support of the tool, a jack being further mounted articulated between two parallel sides of the parallelogram; the annular support includes two toroids parallel joined by crosspieces, each torus is divided into three parts, two of the parts of the torus each being articulated at one of the ends of the third part and the respective position of the three parts being controlled by actuating cylinders connected to each part on either side of each joint; the support locking means comprise a locking cylinder arranged on a crosspiece parallel to the latter and a gusset disposed on an adjacent crosspiece and provided with an opening provided for receiving the rod of the locking cylinder when the support is locked around 'a branch of the structure; the carriage comprises two flanges each maintained in contact with a side of a torus by means of rollers with a curvilinear surface; each torus has a rack disposed along its outer periphery and the carriage comprises a shaft carrying toothed pinions meshing respectively with the racks carried by the support, the shaft carrying the pinions being driven by a hydraulic motor. According to a preferred embodiment, the mobile arm comprises several elongated telescopic elements and means for driving each element as a function of the movements of the adjacent element; the drive means comprise at least one cable formed in an endless loop mounted on rollers carried by an intermediate element to move in a direction parallel to the axis of the telescopic elements, the cable comprising two parallel strands each fixed on a neighboring element on either side of the intermediate element; the movable arm comprises a support tube, an intermediate element and a tubular end element embedded in each other, the support tube comprising a lateral opening and the intermediate element carrying at its rear end a pulley the axis of which is transverse to the the intermediate element and the means of supplying energy to the tool and its accessories comprise a layer of cables or hoses extending inside the final element around the pulley, between the element intermediate, and the support tube

Other characteristics and advantages of the invention will become apparent in the description below.

• - la figure 1 est une vue en perspective schématique d'une réalisation du dispositif selon l'invention utilisée pour le nettoyage des noeuds d'une plate-forme sous-marine ;
• - la figure 2 est une vue en perspective agrandie du dispositif représenté sur la figure 1 ;
• - la figure 3 est une vue partielle du support torique selon l'invention au niveau d'une articulation entre deux parties de tore, en coupe selon le plan III-III de la figure 4 ;
• - la figure 4 est une vue partielle du support selon la direction IV de la figure 3 ;
• - la figure 5 est une vue en coupe transversale selon le plan V-V de la figure 6 d'un mode de réalisation préféré du bras mobile ;
• - la figure 6 est une vue en coupe longitudinale selon le plan VI-VI de la figure 5.

In the appended drawings, given by way of nonlimiting examples:

• - Figure 1 is a schematic perspective view of an embodiment of the device according to the invention used for cleaning the nodes of an underwater platform;
• - Figure 2 is an enlarged perspective view of the device shown in Figure 1;
• - Figure 3 is a partial view of the toroidal support according to the invention at a joint between two toroid parts, in section along the plane III-III of Figure 4;
• - Figure 4 is a partial view of the support in direction IV of Figure 3;
• - Figure 5 is a cross-sectional view along the plane VV of Figure 6 of a preferred embodiment of the movable arm;
• FIG. 6 is a view in longitudinal section along the plane VI-VI of FIG. 5.

Referring now to Figure 1 where there is shown schematically an embodiment of the invention applicable particularly to the cleaning of the nodes of an underwater platform having branches 1, 2, 3, 4 of different diameters, connected together at different angles and forming a knot at each connection.

The device comprises an annular support comprising two tori 5 connected together by crosspieces 6 and supporting a generally designated carriage in 7 being able to move along the toroids 5 transversely to the axis of the branch 4 on which the support is mounted. The carriage 7 carries a tube 8 in which slides a tool-carrying arm 9, at the end of which is fixed a tool support-10 carrying, in the case shown, a brush 11 of frustoconical shape.

The annular support is connected to a remote-controlled submarine 12.

Referring to Figure 2, we see that the submarine 12 conventionally comprises floats 13 arranged in a frame to ensure its lift in the water so that the energy expended by the submarine is essentially used for its movements and for the operation of the device according to the invention. In a conventional manner, the submarine comprises thrusters, video means, navigation means (not shown) and an electric cable 14 ensuring the connection of control and feedback power from the surface.

It is known that this type of submarine generally moves in a vertical plane or a horizontal plane but can hardly take an inclined position. In order to allow easy installation of the annular support, provision is therefore made to make an articulated connection between the submarine and the annular support. This articulated connection comprises a vertical pivot 15 whose angular position is determined by a jack 16 connected in an articulated manner to the chassis of the submarine on the one hand and to the base of the pivot 15 on the other hand. The pivot 15 carries a horizontal arm 17 fixed to the vertical pivot 15 by gussets 18 and whose position in a vertical plane is determined by a jack 19, connected in an articulated manner to the vertical pivot 15 on the one hand and on the side of the arm 17 on the other hand. In addition, the horizontal arm 17 is separated into two parts 17.1 and 17.2 nested one inside the other (see fig. 1) and connected by a hydraulic motor ensuring their angular position relative to each other so that the annular support can be given any desired position and orientation compared to the submarine. In order to prevent the annular support from being subjected to significant forces following the movements of the submarine caused by the movements of the water around the platform, torque limiters will advantageously be provided on the elements ensuring the positioning of the annular support relative to the submarine.

The annular support comprises two identical toroids 5, produced for example by means of light alloy welded and leaktight tubular elements forming a volume ensuring the buoyancy of the support.

Each torus has a part 5.1 rigidly connected to the horizontal arm part 17.2 via a cross member 6.1, and two parts 5.2 each having one of their ends articulated to one of the ends of part 5.1 by l intermediary of gussets 20 carried by crosspieces 6 connecting together two parts of parallel toroids. The relative movement of a torus part 5.2 with respect to the torus part 5.1 is adjusted by a jack 21 articulated on the crosspieces 6. As can be seen in FIG. 2, the torus part 5.1 represents substantially a semi-circle, while each of the toroid parts 5.2 represents substantially a quarter of a circle so that during the complete extension of the jacks 21, the support is open laterally to allow its positioning around one branches of the structure.

Once the annular support is closed on a branch, the locking of the different toroid parts is ensured by means of a jack 22 fixed on a crosspiece parallel to it and cooperating with a gusset 23 carried by a crosspiece of the part torus 5.2 adjacent and having an opening extending from the rod of the jack 22.

The various cylinders are supplied by pipes, not shown, connected to the submarine.

As was said above, the annular support carries a carriage 7 comprising a tubular element 8 in which slides a tool-carrying arm 9 comprising along its lower edge a rack 24 driven by a hydraulic motor 25 carried by the tubular support 8. At its end, the tool-carrying arm 9 comprises a parallelogram comprising two parallel arms 26 and 27 articulated spaced apart on the one hand at the end of the tool-carrying arm 9 and on the other hand on the support of tools 10. A jack 28 is mounted in an articulated manner between the arms 26 and 27, this jack ensures the deformation of the parallelogram and thus makes it possible to move the support of tools relative to the tool-carrying arm in order to bring together or move the tool away from the surface of the branch on which the device is mounted. In order to allow accessibility of the tool, for example a frustoconical brush 11, at relatively closed angles between two branches of the structure, the tool support is preferably made in the shape of an L, the vertical part of the L being made up by a hydraulic motor and the horizontal part containing a connecting means such as a chain or a belt between the hydraulic motor and the tool.

The carriage 7 is constituted by the tubular element 8 on which are fixed flanges 29 arranged symmetrically with respect to a plane located halfway between the toroids 5 parallel to them. Each flange 29 has a lower part substantially matching the shape of the flank of the torus 5 and moves on this flank by means of rollers with curvilinear surface 30 (see the enlarged insert of FIG. 2), each roller 30 being mounted on an axis 31 fixed on the edges of an opening 32 made in the flange 29.

Furthermore, the carriage 7 has an axis 33 whose ends are pivotally held on the flanges 29 and which itself carries toothed pinions 34 cooperating with a rack 35 carried by the toroids 5. The shaft 33 is driven in rotation by a hydraulic motor 36 which thus allows the positioning of the carriage 7 at any point on the external surface of the annular support.

The device further comprises accessories such as cable reels 37 carried by the carriage and preventing tangling of the cables when the carriage moves or when the tool arm is extended.

In order to allow monitoring of the operation performed by the tool, the tool-carrying arm also supports a projector 38 and a video camera 39 appropriately connected to a control installation.

There is shown in Figures 3 and 4 a partial view of the annular support at the junction between the part 5.1 and a part 5.2 of the torus. The sectional view of Figure 3 is taken along a plane parallel to the plane of the toroids 5 while in Figure 4, there is shown a side view of this portion of the annular support, the hinge means 20 and the cylinder 21 however, not being shown in this figure 4.

FIGS. 3 and 4 therefore serve mainly to illustrate the device for centering the annular support which is not shown in FIG. 1 or in FIG. 2.

The centering means comprise a series of arms 40 in the form of a V, the ends of which are articulated on gussets 41 carried by a cross member 6 so as to allow them to pivot around an axis parallel to the cross members 6. The movement of the arm 40 is controlled by jacks 42 hingedly mounted on the one hand on gussets 43 carried by the crosspieces 6 and on the other hand on gussets 44 carried by the arms 40. At the tip of the V, each arm has an appropriate configuration to allow contact with the surface of the branch on which the annular support is to be mounted. One can for example fix at the end of the arm and on the inner side a conical pad 45 made of a material having a high coefficient of elasticity.

Although for the sake of better understanding, the arm 40 of the left part of FIG. 3 has been shown in the raised position, while the arm 40 of the right part and shown in the lowered position, it will be understood that the different control jacks 42 will in practice be connected to a control ensuring synchronization of the movements of the different arms 40 so that during the downward movement of these arms, the toroids 5 are automatically centered on the branch of the structure.

Figures 5 and 6 illustrate a preferred embodiment of the movable arm 9. In this embodiment, the arm 9 comprises two elongated telescopic elements 9.1, 9.2 concentric tubular. The intermediate element 9.1 is supported in the tube 8 by rollers 45, similar to the rollers 30, carried by the tube 8 and whose axes 46 are mounted on the edges of openings made in the tube 8, for example by means of bosses (not shown). The final element 9.2 is placed inside the intermediate element 9.1 and is supported therein by rollers 47 similar to the rollers 45 and whose axes 48 are mounted in the same way as the axes 46 on the edges. openings in the intermediate element 9.1.

Driving means are provided between the element 9.1 and the element 9.2 so that the movements of the element 9.2 take place as a function of the adjacent element 9.1. These drive means include two cables 49 formed in an endless loop each mounted on a pair of rollers 47 of the intermediate element 9.1 to move in a direction parallel to the axis of the elements 9.1 and 9.2. Each cable 49 has an external strand 49.1 and an internal strand 49.2, parallel. The external strand 49.1 is fixed by means of a spacer 50.1 to the tube 8 forming an external element and the internal strand 49.2 is fixed by means of a spacer 50.2 to the final element 9.2. Each strand 49.1, 49.2 is thus fixed to a neighboring element on either side of the intermediate element which supports it. The final element 9.2 also comprises a centering pin 51 cooperating with bosses 52. The telescopic elements being hollow, it is possible to pass the electric cables and the hydraulic or pneumatic hoses 53 inside the final element 9.2 ce which reduces the external dimensions of the arm 9. In the illustrated embodiment, there is provided at the rear of the intermediate element 9.1 a multi-grooved pulley 54 fixed on the rear end of the element 9.1, that is to say say that which is opposite the end of the element 9.2 carrying the working tool (not shown), the axis of the pulley 54 being transverse to the direction of the element 9.1. Starting from the end of the element 9.2 carrying the working tool, the ply 53 of cables and hoses therefore extends inside the element 9.2, around the return pulley 54, between the element 9.1 and the tube 8 and comes out through a lateral opening 55 of the support tube 8 towards a connection to the respective energy sources. For a retracted position of the telescopic elements, the opening 55 is at a distance D from the axis of the pulley equal to the maximum length from which the final element 9.2 must exit relative to the support tube 8.

During the operation of the geared motor 25, this drives the rack 24 carried by the intermediate element 9.1. The relative movement of the element 9.1 relative to the tube 8 causes a similar movement of the cable 49 and therefore a relative displacement of the final element relative to the tube 8 at a speed double that of the element 9.1.

Given the position of the multi-groove pulley at the rear of the element 9.1, it is understood that the speed of the external strand 53.1 of the ply is zero and this arrangement therefore makes it possible to eliminate the reel 37 carried by the tube 38 ; this therefore results in a significant saving both in terms of cost and size.

Different maneuvering means can be envisaged for the device according to the invention. We can first of all consider a direct control means using a video camera placed near the tool and allowing an operator to follow each movement of the tool and ensure its positioning by acting on the hydraulic elements 6 , 25 and 28 respectively for controlling the position of the carriage, the extension of the tool arm and the distance of the tool from the surface of the branch of the structure.

We can also consider semi-automated or fully automated maneuvers. In particular, provision may be made to keep the tool pressed against the surface of the branch and against the adjacent branch by means of an adequate calibration device for the hydraulic pressure in the motor 25 and the jack 28. The tool then follows automatically the knot as the carriage 7 rotates around the branch.

It is also possible to envisage storing the path that the tool must follow for given values of the diameter of the branch on which the device is arranged, the diameter of the immediately adjacent branch and the angle between the two branches . During the installation of the device on a branch of the structure, the memory part containing the corresponding information is selected and the course of the maneuver is then carried out automatically.

According to yet another maneuvering method, provision can be made to carry out a first follow-up of the knot between two branches without movement of the tool and by recording the corresponding movements of the carriage and of the tool-carrying arm, then one or more follow-ups of the knot automatically controlled by memory, this time using the tool. In the case of cleaning, this process makes it possible in particular to carry out the first monitoring by means of a video camera without polluting the surrounding water and then to carry out cleaning while the video camera could no longer be used due to the reduced visibility due to brush movement. Although the invention has been described in connection with figures where the tool shown is a rotary brush, it will be understood that it is possible to use all kinds of tools. In particular, after having carried out a cleaning, it is possible to replace the cleaning tool with a control tool or with a tool making it possible to work on the knot.

Similarly, although the device according to the invention is particularly suitable for working on an underwater structure, it could also be used on an aerial structure.

The present invention is not limited to the examples which have just been described and numerous modifications can be made to them without departing from the scope of the invention.

Claims (10)

1. Device for performing work on an underwater structure with several branches comprising an annular support (5, 6) articulated so as to be able to be locked around one of the branches of the structure, a carriage (7) mounted on the annular and movable support in a transverse direction relative to the axis of the annular support, a drive means (34) of the carriage along the support, means for supplying energy to a tool and accessories the tool, and an arm (9) adapted to support the tools and its accessories and supported by the carriage, characterized in that the arm is movable in at least one direction substantially parallel to the axis of the annular support, and is connected a drive means (25) of the arm relative to the carriage. 2. Device according to claim 1, characterized in that the tool-carrying arm comprises at one end an articulated parallelogram of which two articulations are mounted in a spaced manner at the end of the tool-carrying arm while the other two articulations are mounted spaced apart on a support of the tool, a jack (28) being, moreover, articulated between two parallel sides (26, 27) of the parallelogram. 3. Device according to claim 1 or claim 2, characterized in that the movable arm comprises several elongated telescopic elements and means for driving each element according to the movements of the adjacent element. 4. Device according to claim 3, characterized in that the drive means comprise at least a cable formed in an endless loop, mounted on rollers carried by an intermediate element to move in a direction parallel to the axis of the telescopic elements, the cable comprising two parallel strands, each fixed to a neighboring element, on the one hand and on the other side of the intermediate element. 5. Device according to claim 3 or claim 4, characterized in that the movable arm comprises a support tube (8), an intermediate element (9.1) and a tubular end element (9.2) embedded in each other, the tube support (8) comprising a lateral opening (55) and the intermediate element (9.1) carrying, at its rear end, a pulley (54) whose axis is transverse to the intermediate element (9.1), and in that the power supply means of the tool and its accessories comprise a layer of cables or hoses extending inside the final element (9.2) around the pulley (54), between the element intermediate (9.1) and the support tube (8) and through the lateral opening (55). 6. Device according to one of claims 1 to 5, characterized in that the support comprises two tori (5) parallel and joined by crosspieces (6). 7. Device according to claim 6, characterized in that each torus is divided into three parts, two of the parts (5.2) of the torus each being articulated at one of the ends of the third part (5.1), and in that the respective position of the three parts is controlled by actuating jacks (21) connected to each part on either side of each articulation. 8. Device according to claim 7, characterized in that the support locking means comprise a locking cylinder (22) disposed on a cross member parallel to the latter and a gusset (23) disposed on an adjacent cross member and provided with an opening provided to receive the rod of the locking cylinder when the support is locked around a branch of the structure. 9. Device according to claim 6, characterized.en that the carriage comprises two flanges (29) each maintained in contact with a flank of a torus by means of rollers (30) with curvilinear surface. 10. Device according to claim 6, characterized in that each torus carries a rack (35) disposed along its outer periphery and in that the carriage comprises a shaft (33) carrying toothed pinions (34) respectively meshing with the racks carried by the support, the shaft carrying the pinions being driven by a hydraulic motor (36).

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