OA19066A - Machine et procédé pour la pose simultanée et en hélice de câbles sur la surface externe d'un élément unitaire de conduite de transport de fluides. - Google Patents

Abstract

L'invention concerne une machine (4) et un procédé pour la pose en hélice de câbles sur la surface externe d'un élément unitaire de conduite (2) de transport de fluides, comprenant un cadre rotatif (14) destiné à être centré autour d'un axe de symétrie (X-X) de l'élément unitaire de conduite, le cadre supportant une pluralité d'éléments de bobinage destinés à recevoir des câbles, situés chacun dans un plan longitudinal à l'élément unitaire de conduite et espacés les uns des autres autour de l'axe de symétrie de l'élément unitaire de conduite, des moyens pour régler l'inclinaison de chaque élément de bobinage par rapport au plan longitudinal dans lequel il se situe, un moteur pas à pas de déplacement linéaire pour déplacer le cadre le long de l'élément unitaire de conduite, et un moteur pas à pas de déplacement rotatif pour faire pivoter le cadre autour de l'axe de symétrie de l'élément unitaire de conduite.

Description

Title of the invention

Machine and method for the simultaneous and helical laying of cables on the outer surface of a unitary fluid transport pipe element

Background of the invention

The present invention relates to the general field of fluid transport conduits for the transfer of hydrocarbons, for example oil and gas, coming from subsea production wells.

It relates more precisely to a machine making it possible to deposit in a helix (one also speaks of “spiraling”) several cables (for example electric heating cables) simultaneously on the outer surface of such pipes.

There are different types of subsea pipelines used for the transportation of hydrocarbon fluids, single or double jacketed. The invention relates more particularly to double-cased pipes of the “Pipe In Pipe” or PIP type, that is to say “pipe in a pipe”, in which an internal steel casing conveys the fluids and a pipe. outer steel casing coaxial with the previous one is in contact with the surrounding environment, that is to say with water.

Generally, double-walled pipes are assembled on land in units of unit length (we speak of unitary pipe units or trains), of the order of 10 to 100 m depending on the load-carrying capacity of the laying system. These unit control elements are then transported at sea on a laying vessel. During installation, they are connected to each other on board the ship and as they are laid at sea.

Furthermore, it is known practice to heat jacketed pipes over their entire length by means of a plurality of electric cables which are wound around the outer surface of the inner casing of the pipes in order to heat it by the Joule effect. This heating solution, which is called "traced heating" (or "heat tracing" in English), keeps the hydrocarbon fluids transported in the underwater pipes at a temperature above a critical threshold throughout their path since the production well up to the surface installation, and thus to avoid the formation of hydrate crystals or other solid deposits leading to the creation of plugs capable of blocking the submarine pipe.

Typically, electric heating cables are flat cables which are provided with a rubber protection and which are deposited in a helix on the external surface of the internal casing of each unit pipe element. In practice, this laying is generally carried out individually for each unit pipe element by unwinding the various electric cables from a fixed station, the internal casing of the unit pipe element being moved longitudinally through the fixed station. To this end, the internal casing of the single pipe element is positioned on a support which moves it longitudinally through the fixed station while causing it to undergo a rotation around its axis of symmetry to allow the cables to be deposited. on the outer surface of the inner shell with a helical motion.

This type of helical laying of cables by means of a fixed station through which the unitary pipe element translates, however, has a certain number of drawbacks. Indeed, due to the forward movement of the internal casing of the unitary pipe element which is both longitudinal and rotary, the cables are necessarily deposited on the outer surface of the inner casing with a torsional movement. . However, this torsional stress induced on the cables during their laying is likely to create loops in the cables once they have been deposited. In addition, the buildup of residual torsion can result in the formation of knots damaging the cables and pulling them off the outer surface of the inner pipe casing. Moreover, this type of helical laying requires a displacement of the internal pipe of the unitary pipe element which requires a relatively complex - and therefore expensive - mechanism to develop.

Purpose and summary of the invention

The main object of the present invention is therefore to provide a machine for the helical laying of cables which does not have the aforementioned drawbacks.

According to the invention, this object is achieved by means of a machine for the simultaneous and helical laying of cables on the external surface of a unitary fluid transport pipe element, comprising:

a rotary frame intended to be centered around an axis of symmetry of the single pipe element, the frame supporting a plurality of winding elements intended to receive cables to be laid on the single pipe element, the elements of coil being each located in a plane substantially longitudinal to the unit pipe element and spaced from each other around the axis of symmetry of the unit pipe member;

means for adjusting the inclination of each winding element relative to the longitudinal plane in which it is located;

a linear displacement stepper motor for moving the frame along the driving unit member; and a rotary displacement stepper motor for rotating the frame about the axis of symmetry of the driving unit member.

The invention thus proposes to simultaneously lay several helical cables from a machine which moves along the unitary pipe element, the latter remaining fixed during the laying process. The machine according to the invention thus has a simplified design with respect to a machine having to linearly move the unitary pipe element while causing it to pivot about its axis. In addition, the winding elements being each located in a plane substantially longitudinal to the single pipe element, it is possible to lay the cables in a helix on the outer surface of the single pipe element without exerting stress on the latter. torsion, which avoids the problems inherent in this type of stress.

Advantageously, each winding element comprises: a storage reel on which is wound the cable to be laid on the single pipe element;

a reel reel for receiving one end of the cable unwound from the storage reel to bring it onto the outer surface of the unitary conduit member;

a guide system for guiding the cable unwound from the storage reel to the outer surface of the unit conductor member; and a compression system for applying a compressive force to the cable coming to rest on the outer surface of the unitary pipe element.

The compression system of each winding element may include a telescopic rod, one end of which is fixed to the unwinding reel and an opposite end is connected to a roller with the interposition of a spring, said roller being able to roll on the surface. of the unit guide element when laying the cable. In this way, the roller makes it possible to apply a compressive force to the cable coming to be deposited on the external surface of the single pipe element, and thus to improve its fixing.

Likewise, the guiding system of each winding element may comprise a roller device for automatically removing plastic bands covering strips of adhesive from the cable prior to laying said cable on the outer surface of the unitary pipe element, and a deflector for guiding the cable from the reel spool to the roller device. The adhesive strips advantageously make it possible to secure the cable to the external surface of the unitary pipe element. In this case, the roller device may comprise a drive roller intended to receive a free end of the cable coming from the unwinding reel and the winding rollers on which the plastic bands detached from the cable are intended to be wound up.

The storage and reel spools can advantageously each be provided with a braking system. The presence of such a braking system makes it possible, on the one hand, to apply a tension during the laying of the cable, and on the other hand to slow down the reels rapidly at the end of laying.

Each winding element can be mounted on one face of the frame by means of a plate capable of pivoting in a radial direction with respect to the axis of symmetry of the single pipe element, the frame further comprising a system worm screw coupled to each plate to adjust the inclination of each winding element relative to the longitudinal plane in which it is located. In this case, the endless screw systems are preferably synchronized with one another to make it possible to give the same inclination to each winding element.

The machine may further include a carriage supporting the frame by means of a guide ring intended to be centered on the axis of symmetry of the unit driving element, the carriage being provided with wheels driven by the stepper motor. linearly moving and adapted to move along a guide rail.

In this case, the guide ring of the carriage may include a toothed wheel which is rotated by the rotary displacement stepper motor. In addition, the carriage may include means for adjusting the vertical position and the horizontal position of the frame, and guide rollers for the unitary driving element.

Preferably, the machine further comprises optical means for determining the distance between the frame and one end of the unit pipe element towards which the frame moves. These optical means thus make it possible not only to monitor with precision the progress of the laying of the cables, but also to control the rotary movement of the frame with its linear displacement.

The frame may have a polygon shape with several faces on which the winding elements are mounted.

The subject of the invention is also a method for laying cables in a helix on the outer surface of a unitary fluid transport pipe element by means of a machine as defined above, comprising:

the positioning of the rotary frame of the machine about an axis of symmetry of the unitary pipe element at one of the ends thereof; and driving the linear displacement and rotary displacement stepper motors of the machine to allow linear advance of the machine towards the opposite end of the drive unit member with synchronized rotation of its rotary frame to ensure the simultaneous helical laying of all the cables on the external surface of the single posecA element

Brief description of the drawings

Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate an exemplary embodiment thereof without any limiting nature. In the figures:

- Figure 1 is a perspective view showing in situation a spiraling machine according to one embodiment of the invention;

FIG. 2 shows an example of a support for a unitary pipe element which can be used in association with the spiraling machine of FIG. 1;

- Figure 3 shows in more detail the linear movement of the spiraling machine of Figure 1;

- Figure 4 is a side view of the spiraling machine of Figure 1;

- Figure 5 is a three-quarter front view of the spiraling machine without its rotating frame;

- Figure 6 is a magnifying glass of Figure 5 showing the pivoting mechanism of the rotary frame relative to the carriage;

- Figures 7 and 8 are perspective views of the rotary frame of the spiraling machine, respectively in downstream view and in upstream view;

- Figure 9 shows in detail the supporting structure of the rotary frame of Figures 7 and 8;

FIG. 10 is a perspective view of a winding element of the spiraling machine of FIG. 1;

FIG. 11 is a side view of a reel spool of the winding element of FIG. 10;

- Figure 12 shows a roller device of the guide system of the winding element of Figure 10;

- Figure 13 is a bottom view of the roller device of Figure 12;

FIG. 14 shows in perspective a system for compressing the winding element of FIG. 10;

FIG. 15 is a front view of the rotary frame of the spiraling machine of FIG. 1;

FIG. 16 is a partial perspective view of the rotary frame of FIG. 15 showing in more detail the mechanism for adjusting the inclination of each winding element;

- Figure 17 is a magnifying glass of Figure 16; and

FIG. 18 partially shows a unitary pipe element, the outer surface of which comprises cables laid helically by means of the spiraling machine of FIG. 1.

Detailed description of the invention

The invention relates to a machine for simultaneously laying cables in a helix on the outer surface of a unitary subsea pipe element (hereinafter referred to as a “spiraling machine”) such as that shown in FIG. 1.

The cables laid can be electrical cables wound around the external surface of the internal envelope of a submarine double jacket to heat it by the Joule effect (in the case of traced heating) or coiled fiber optic cables around the outer surface of the inner casing of a double-cased submarine pipe to monitor the mechanical deformations applied to them.

Typically, such cables are flat cables which are provided with a rubber protection and which are covered on one of their faces with two strips of adhesive which allow them to be held on this surface, these strips of adhesive being protected by plastic bands.

In Figure 1, there is shown a single pipe element 2 intended, once assembled to other single pipe elements, to form the casing of an underwater pipe (for example the internal casing of a pipe. jacketed), as well as a spiraling machine 4 according to the invention.

The unitary pipe element 2 is positioned horizontally above the ground while being supported by a plurality of supports 6 (six in number in the figure) regularly spaced from one another.

As shown in more detail in FIG. 2, the supports 6 are studs which are provided in the lower part 6a with rollers 8 to be moved and in the upper part 6b with a seat 10 of rounded shape on which the unit element rests. driving.

The height of the seat 10 of these supports 6 can be adjusted, for example by means of a pneumatic cylinder 12. In addition, this seat 10 is preferably provided with elastomer bands 12 to limit the crushing of the cables. laid on the outer surface of the single pipe element.

The spiraling machine 4 according to the invention is doubly mobile with respect to the unitary pipe element fixed and resting horizontally on the supports 6: it is capable of moving linearly along the unit pipe element 2, while at the same time being able to pivot about an axis of symmetry XX thereof.

In addition, the spiraling machine 4 according to the invention mainly consists of a rotating frame 14 provided with the actual spiraling means (described later) and a movable carriage 16 supporting the frame (FIG. 4).

As shown in Fig. 3, to move along the drive unit member, the movable carriage 16 of the spiraling machine is provided with wheels 18 which are driven by a linear displacement stepper motor 20 and which are guided on a rail 22 placed on the ground parallel to the unitary pipe element 2.

Figures 4 to 6 show in more detail the structure of the movable carriage 16 of the spiraling machine according to the invention. This carriage has a lower platform 16a under which the wheels 18 are mounted, as well as a substantially vertical upper platform 16b.

At its upper platform, the movable carriage 16 supports the rotary frame 14 by means of a guide ring 24 which is positioned so as to be centered on the axis of symmetry X-X of the unit driving element.

At its periphery, the guide ring 24 of the mobile carriage carries a toothed wheel 26 (see FIG. 6) which is also centered on the axis XX and which is rotated by a rotary displacement stepper motor 28. By actuation of the rotary displacement stepper motor 28, the toothed wheel 26 is able to pivot about the axis XX, thus rotating the rotary frame 24 provided with the actual spiraling means around the unit driving element.

The guide ring 24 of the movable carriage also comprises a window 30, for example of square shape, intended to be traversed by the unit driving element during the linear movement of the spiraling machine. Guide rollers 32 positioned inside this window 30 make it possible to ensure good centering of the unit driving element during the linear movement of the spiraling machine.

At its upper platform, the mobile carriage 16 also carries two lasers 36 (FIG. 5). These lasers are calibrated to emit an optical beam downstream (relative to the linear movement of the spiraling machine) in the direction of a reflecting panel (not shown in the figures) positioned at the end of the unit pipe element. These optical means thus make it possible not only to monitor with precision the progress of the laying of the cables, but also to control the rotary movement of the spiraling machine with its linear displacement.

Furthermore, still at its upper platform 16b, the movable carriage 16 comprises means for adjusting the vertical position and the horizontal position of the rotary frame 14 of the spiraling machine.

For example, these means are in the form of rollers 38a arranged vertically and rollers 38b arranged horizontally which make it possible to move in the vertical and horizontal directions the guide ring 24 supporting the rotary frame 14 of the spiraling machine (FIG. 5) . A counterweight system 40 may make it possible to facilitate the adjustment of the vertical position of the frame.

Finally, a system of rods 42 connecting the upper platform 16b to the lower platform 16a of the mobile carriage makes it possible to adjust the verticality of the upper platform 16b of the carriage.

In connection with Figures 7 to 14, we will now describe different characteristics of the rotary frame 14 of the spiraling machine according to the invention.

As indicated above, the rotary frame 14 is provided with the winding means proper and is able to pivot about the axis of symmetry X-X of the unitary pipe element.

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For this purpose, the rotary frame comprises a support structure 44 having a polygon shape with a plurality of faces on which are mounted winding elements 46. On each of the faces of this polygonal structure is mounted a winding element 46.

In the example illustrated, the support structure 44 has the shape of a nonagon with nine faces making it possible to support nine winding elements 46.

In this exemplary embodiment, provision is thus made to simultaneously lay nine helical cables on the outer surface of the single pipe element. Of course, depending on the number of cables to be laid, the support structure of the rotating frame could have a different shape.

The winding elements 46 are intended to receive cables to be laid helically on the single pipe element. These winding elements are regularly spaced from each other around the axis of symmetry X-X of the unit pipe element and are each located in a plane P which is substantially longitudinal to the unit pipe element.

More precisely, each winding element 46 comprises in particular a storage reel 48 on which is wound the cable to be laid provided with its plastic bands, as well as a reel reel 50 intended to receive one end of the cable unwound from the reel. storage to bring it to the outer surface of the unitary pipe element, the storage and unwinding coils of each winding element being aligned in the plane P.

As shown in FIG. 10, each winding element 46 also comprises a guide system for guiding the cable unwound from the storage spool 48 towards the outer surface of the unitary conduit element.

The guiding system of each winding element more precisely comprises a roller device 52 for automatically removing the plastic bands covering the two adhesive bands of the cable prior to the laying of the latter on the outer surface of the single pipe element. .

This roller device 52 is visible in detail in Figure 12. It consists of a drive roller 54 which is intended to receive ^ a free end of the cable coming from the unwinder reel 50 and two winding rollers. 56 mounted on a support 58 and on which the two plastic bands which have been detached from the cable are intended to be wound.

These rollers 54, 56 have respective axes of rotation A54, A56 which are parallel (the winding rollers 56 are coaxial). The rollers are also positioned in contact with each other so that the drive roller 54 drives the two winding rollers 56 in rotation. In addition, the winding rollers 56 are movable in translation. along an axial groove 57.

As shown in FIG. 13, the winding rollers 56 of this device each have a notch 59 intended to receive one end of a plastic strip (not shown in the figure) to be detached from the cable.

The cable still coated with its two plastic bands passes between the drive roller 54 and the two winding rollers 56 as shown diagrammatically by the arrow F in FIG. 12. A spring 62, one end of which is fixed on the support 58 of the rollers. winding 56 keeps the latter always in contact with the drive roller 54. The end of the plastic bands being anchored in the respective notches 59 of the winding rollers, these bands are wound around the rollers. winding as the cable passes between the two rollers 54, 56.

In addition, as the two plastic bands come to wind on the winding rollers 56, the diameter of the latter increases, so that the axis A56 of the winding rollers shifts by translating axially. in the groove 57. The presence of the spring 62 makes it possible to keep the drive rollers and winding rollers in contact with each other despite this axial translation of the axis of the winding rollers.

The guiding system of each winding element also comprises a deflector 64 for guiding the cable from the reel spool 50 towards the roller device 52 previously described, then towards the outer surface of the unit conductor element. As shown in Figure 10, the presence of such a funnel-shaped deflector 64 ending in a ramp makes it possible in particular to prevent the cable from getting stuck during its movement from the reel spool towards the unitary element. driving.

According to an advantageous arrangement of the invention illustrated in FIG. 11, the storage coils 48 and unwinder 50 of each coil element are each provided with a braking system.

The coils 48, 50 which are mounted on a sliding bearing (not shown in the figures) are each provided with an adjustable braking band 66 which are fixed at one end by a hook system 68 and connected at the end to a spring system 70. The latter makes it possible to generate on the coils a counter-rotating force (of the order of a few Newtons) which ensures, on the one hand, a tension force on the cable during its laying, and d on the other hand a gradual slowing down of the coils when the cable laying process is stopped.

As shown in particular in Figures 10 and 14, each winding element further comprises a compression system to apply a compressive force to the cable coming to rest on the outer surface of the unit pipe element.

The compression system comprises a telescopic rod 72, one end of which is fixed to the unwinder reel 50 and an opposite end is connected to a roller 74 with the interposition of a spring 76. More precisely, the roller 74 is fixed at the end. of the rod 72, the latter being able to slide inside a sleeve 78, the spring 76 being interposed between the rod and the sleeve.

In this way, the spring 76 makes it possible to apply pressure on the roller to keep the latter in contact with the external surface of the unitary guide element during the laying of the cable. Thus, the roller 74 rolls on the outer surface of the single pipe element and constantly exerts a compressive force on the cable during its installation, and this regardless of the concentricity defects of the single pipe element.

In addition, the roller 74 can take two positions: a so-called working position in which the spring exerts pressure on it when laying the cable, and a rest position (not shown in the figures) in which the rod 72 carrying the roller is retracted inside the sleeve 78 and locked in this position by means of a pin 80. ώΑ

According to another advantageous arrangement of the invention, each winding element 46 is mounted on one face of the support structure 44 by means of a plate 82 (see Figures 10, 16 and 17) which is able to pivot. around a radial axis YY with respect to the axis of symmetry XX of the single pipe element (see figure 15).

In particular, each winding element 46 is integral with a plate 82 which is fixed to the support structure 44, the storage coils 48 and unwinder 50 of each winding element being positioned on the exterior side of the support structure, while the roller device 52 and the compression system protrude from the interior side through windows 84 made in the support structure (see Figure 9).

Furthermore, each plate 82 is coupled for the adjustment of its pivoting about the radial axes YY to a worm system 86. By adjusting the pivoting of the plates 82 relative to the radial axes YY, the inclination of each is thus adjusted. winding element 46 relative to the longitudinal plane P in which it is located. This adjustment makes it possible in particular to limit the effect of torsion exerted on the cables by the rotation of the frame of the spiraling machine during their laying on the outer surface of the unitary pipe element.

Preferably, these worm screw systems 86 are synchronized with one another to make it possible to give the same inclination to each winding element. For this purpose, the endless systems of the spiraling machine are fixed to each other by cardan joints 88 (see FIG. 16 in particular).

An example of application of the spiraling machine according to the invention to the simultaneous laying of helical cables on the external surface of a unitary pipe element is described below.

In this example of application, the unitary pipe element has a length of 50m and an attempt is made to lay nine helical cables on its outer surface, for example with a helix pitch of 6m. The helix pitch is obtained by adjusting the inclination of each winding element 46 relative to the longitudinal plane P in which it is located.

As shown in Figure 1, the single pipe element 2 is positioned horizontally on the supports 6. For a single pipe element having a length of 50m, there will be for example six supports 6 spaced 10m apart with a support. at each end of the unit pipe element.

The spiraling machine 2 is positioned at one of the ends of the unit pipe element with its rotating frame 14 disposed around the unit pipe member. The lasers 36 of the spiraling machine are pointed in the direction of the reflective panel positioned at the other end of the unit pipe element.

The linear displacement stepper motor 20 and the rotary displacement stepper motor 28 of the spiraling machine are controlled remotely from a workstation (not shown in the figures). Using the measurement of the linear advance of the spiraling machine obtained by means of optical means (lasers 36 and reflecting panel), the workstation makes it possible in particular to synchronize these two motors 20, 28 to make it possible to ensure a laying of the nine cables with the desired propeller pitch and according to the linear displacement speed of the carriage of the spiraling machine. Knowing the progress of the spiraling machine, the workstation adapts the speed of rotation of the rotating frame. In particular, when the rotation is late, the workstation imposes a higher rotation speed to make up for the delay (and vice versa).

Different programming of the motors 20, 28 is possible. Stepper motors can be programmed to operate in "speed mode" in which the programmed reference is a machine advance speed reference (for example 5m / min). Stepper motors can also be programmed to operate in "motor torque mode" in which the programmed reference is a motor torque reference. Stepper motors can still be programmed to operate in "position mode" in which the programmed reference is the number of motor steps (for example 5000 steps).

Once the stepper motors 20, 28 have been programmed at the workstation, the spiraling machine advances linearly towards the opposite end of the driving unit member with a synchronized rotation of its rotating frame in order to ensure the simultaneous helical laying of all nine cables on the external surface of the single laying element. The stopping of the advance of the spiraling machine is carried out automatically thanks to the optical means.

FIG. 18 shows the result of the spiraling with the outer surface of the unitary pipe element 2 which has nine cables 90 5 laid helically.

Claims (13)

1. Machine (4) for helically laying cables (90) on the external surface of a unitary pipe element (2) for transporting fluids, comprising: a rotary frame (14) intended to be centered around an axis of symmetry (XX) of the unitary pipe element, the frame supporting a plurality of winding elements (46) intended to receive cables to be laid on the 'unitary pipe element, the winding elements being each located in a plane (P) substantially longitudinal to the unitary pipe element and spaced from one another around the axis of symmetry of the unitary pipe element; means (82, 86) for adjusting the inclination of each winding element relative to the longitudinal plane in which it is located; a linear displacement stepper motor (20) for moving the frame along the unitary driving member; and a rotary displacement stepper motor (28) for pivoting the frame about the axis of symmetry of the unitary driving member; each winding element (46) comprising: a storage reel (48) on which is wound the cable to be laid on the unitary pipe element; a reel of reel (50) intended to receive one end of the cable unwound from the storage reel to bring it on the external surface of the unitary conduit element; a guidance system for guiding the unwound cable from the storage reel to the external surface of the unitary conduit member; and a compression system for applying a compression force to the cable which comes to rest on the external surface of the unitary pipe element. 2. Machine according to claim 1, wherein the compression system of each winding element comprises a telescopic rod (72), one end of which is fixed to the reel of reel and an opposite end is connected to a roller (74) with interposition a spring (76), said roller being able to come to roll on the external surface of the unitary guide element during the laying of the cable. 3. Machine according to one of claims 1 and 2, in which the guide system of each winding element comprises: a roller device (52) for automatically removing plastic strips covering strips of adhesive from the cable prior to laying said cable on the external surface of the unitary conduit member; and a deflector (64) for guiding the cable from the reel spool to the roller device. 4. Machine according to claim 3, wherein the roller device (52) comprises a drive roller (54) intended to receive a free end of the cable coming from the reel spool and the winding rollers (56) on which are intended to wind the plastic strips peeled off from the cable. 5. Machine according to any one of claims 1 to 4, wherein the storage reels (48) and reel (50) are each provided with a braking system (66, 68, 70). 6. Machine according to any one of claims 1 to 5, in which each winding element is mounted on one face of the frame by means of a plate (82) able to pivot around a radial axis (YY) relative to the axis of symmetry (XX) of the unitary driving element, the frame further comprising a worm system (86) coupled to each plate to adjust the inclination of each winding element relative to the longitudinal plane in which it is located. 7. Machine according to claim 6, wherein the worm systems (86) are synchronized with each other to allow to give the same inclination to each winding element. 8. Machine according to any one of claims 1 to 6, further comprising a carriage (16) supporting the frame (14) by means of a guide ring (24) intended to be centered on the axis of symmetry of the unitary driving element, the carriage being provided with wheels (18) driven by the stepping motor of linear displacement and able to move along a guide rail (22). 9. Machine according to claim 8, wherein the guide ring (24) of the carriage comprises a toothed wheel (26) which is rotated by the rotary movement stepper motor. 10. Machine according to one of claims 8 and 9, in which the carriage (16) comprises: means (38a, 38b) for adjusting the vertical position and the horizontal position of the frame; and guide rollers (32) for the unitary driving member. 11. Machine according to any one of claims 1 to 10, further comprising optical means (36) for determining the distance between the frame and one end of the unitary pipe element towards which the frame moves. 12. Machine according to any one of claims 1 to 11, wherein the frame has a polygon shape with several faces on which are mounted the winding elements. 13. A method of helically laying cables on the external surface of a unitary pipe element (2) for transporting fluids by means of a machine according to any one of claims 1 to 12, comprising: positioning the rotary frame (14) of the machine around an axis of symmetry (X-X) of the unitary driving element at one of its ends; and controlling the linear displacement and rotary displacement stepping motors (20, 28) of the machine to allow a linear advance of the machine towards the opposite end of the unitary driving element with a synchronized rotation of its frame rotatable to ensure ^ the simultaneous laying in a helix of all the cables on the external surface of the unitary laying element.