BE1027988B1 - Fluid conduit protection system - Google Patents

Abstract

The protection system (1) comprises: - an inner layer (6) made of a flexible material, compressible, and permeable to a filling fluid (19) and a flexible protective sheet (10), wound around an area in protecting (2) from conduits (3) of fluid, to form a closed enclosure; - a circumferential clamping device (20) of the protective sheet in the assembled state; - means for limiting the degree of circumferential tightening of the protective ply (10) by means of the tightening device (20), so that a predetermined minimum distance (e) is provided between the area to be protected (2) and the protective sheet (10).

Description

System for protecting a fluid conduit The invention relates to a system for protecting an area to be protected by at least one fluid conduit.

The invention applies to networks of fluids - in particular electricity, gas, water or information - comprising conduits - in particular cables or pipes - located under or above the surface of the ground.

In practice, certain areas of these networks are more vulnerable to external attacks and must therefore be protected.

This concerns, for example, a damaged area of a duct, or a connection area between two or more conduits, typically forming a connection or a bypass.

After the intervention, whether in the aforementioned examples of a repair or a connection, the affected area of the duct (s) must again be protected, in terms of sealing and / or electrical insulation. .

To this end, it is known practice to place an envelope around the area to be protected and to introduce a filling fluid therein to fill the space between the envelope and the area to be protected.

Such a filling fluid generally has the function of ensuring mechanical rigidity and of providing sealing, in particular in order to prevent short circuits, leaks or corrosion.

In practice, an operator first winds a stuffing tape around the area to be protected, making several turns and creating overlaps, to form an inner layer of the future envelope.

Then he covers this set with a waterproof film, typically an adhesive tape, which is also wound in several turns with overlaps.

The filling material is then introduced through an appropriately placed nozzle.

These operations are particularly long, and therefore expensive.

In addition, they require the operator's expertise to guarantee the quality of the assembly and therefore the effectiveness of the protection by the casing thus achieved, including over time.

The present invention aims to remedy all or part of the drawbacks mentioned above.

To this end, the invention relates to a system for protecting an area to be protected from at least one fluid conduit, comprising:

an inner layer made of a flexible, compressible material permeable to a filling fluid of the protection system; - a flexible protective sheet; the protection system being configured so that, in the assembled state, the protective sheet is wound around the inner layer itself wound around the area to be protected, so as to form a closed enclosure which encompasses the area to be protected and into which the filling fluid can be introduced, the protection system further comprising a device for circumferential tightening of the protective sheet in the mounted state.

According to a general definition of the invention, the protection system further comprises limiting means configured to limit the degree of circumferential tightening of the protective ply by means of the tightening device, and thus to limit the degree of compression of the inner layer in the zone to be protected, at a distance from the axial ends of the protective ply, so that a predetermined minimum distance is provided between the zone to be protected and the protective ply.

The limiting means thus aim to limit the degree of compression of the inner layer. In other words, the space surrounding the area to be protected has a radial thickness greater than a predetermined thickness, for example of the order of 5 mm. This predetermined thickness may be imposed by certain regulations or by certain players in the industrial sector concerned. Indeed, it is the thickness of the filling fluid, in the final state, which guarantees the effectiveness of the protection, in particular the tightness (in particular in the event of perforation of the flexible sheet) and the mechanical resistance to shocks.

The limiting means of the invention make it possible to overcome variations in the amount of tightening from one operator to another, limiting the hazards of this manual operation. The invention makes it possible to guarantee a minimum residual thickness, even homogeneous throughout the area to be protected, that is to say a sufficient quantity of filling fluid in the final state. In particular, the invention makes it possible to ensure a non-zero thickness of the filling fluid opposite the sharp corners, in the zone to be protected.

It should be noted that this minimum thickness is present in the zone to be protected, which does not include the axial ends of the sheet, which are generally located at a distance from the zone to be protected and are tightened with sealing around the duct (s). of fluid, without filling fluid thickness.

Preferably, the limiting means are restrictive, that is to say they prevent an assembly operator from exerting too much tightening. This is particularly advantageous because the minimum thickness is guaranteed in a safe manner, without risk of error, without the operator having to take special precautions when tightening. As a variant, provision could be made for the limiting means to be merely indicative (such as for example visual references), the assembly operator then having to follow the indications in order not to exert too much tightening.

The limiting means can be arranged on the clamping device.

According to one embodiment, the tightening device comprises at least one strap which extends over at least part of the circumference of the protection system, in the mounted state, the strap comprising first hooking means which are arranged to cooperate with second hooking means arranged on the protection system, the first and second hooking means being positioned and / or dimensioned to allow adjustment of the clamping between a predetermined minimum diameter and a maximum diameter.

The second attachment means can for example be arranged at another location on the strap, or on the outer face of the web. The first and second attachment means can be localized, that is to say present in defined places but not elsewhere.

The cooperation between the first and second attachment means can take place within a predefined limited cooperation area, thus providing adjustment within a predetermined amplitude range, not below, not beyond.

For example, the first and second hooking means are provided on the strap and include one of the loops, the other hooks, to form a Velcro® type hook. The tightening adjustment can thus be carried out continuously. As a variant, the tightening adjustment could be carried out discreetly, for example via a system of the belt buckle type.

According to another embodiment, the tightening device comprises at least one strap which extends over at least part of the circumference of the protection system, in the mounted state, the strap having a fixed length and comprising first means. hooking which are arranged to cooperate with second hooking means arranged on the protection system, in a single hooking position generating a predetermined degree of tightening.

In this case, no adjustment of the tightening is possible, either via the length of the strap or via the positioning of the hooking zone. The required clamping amount must therefore be precalculated and calibrated. Such a clamping device is designed for one type of area to be protected, and is not adaptable to another type of area to be protected. Here again, the second hooking means can be arranged at another location on the strap or on the outer face of the web.

As a variant or in addition, the limiting means can be arranged on the protective sheet. It is possible to have limiting means both on the clamping device and on the protective ply.

The limiting means may comprise at least one spacer mounted on the protection system on the side of the inner face of the web, the spacer having a predetermined height and being configured to abut against the duct or another element of the zone. to protect, at least to the right of the clamping means. Such an element can be a connector between cables, for example. The spacer can locally compress the inner layer or sink into it. The spacer can be mounted on the inner face of the protective sheet, or in the inner layer. The spacer preferably has sufficient mechanical rigidity not to be deformed by the clamping, in the clamping range used.

The protective sheet can be made of a material which is electrically insulating and / or waterproof.

Provision can be made for the protective sheet to be non-planar, for example preformed into an open cavity, before its implementation. For example, the web may form a dihedral (ie two substantially planar walls forming an angle between them) or a section (ie have a curved shape).

According to one possible embodiment, the protective sheet comprises two sections configured to be placed on either side of the zone to be protected and to be assembled to one another with zero overlap or which, seen in a transverse plane, is less than 50 °, preferably less than 20 °.

In other words, the protective web is not formed by winding a tape several turns, or even a piece. This considerably reduces the assembly time. In addition, such a configuration makes it possible to guarantee a good positioning of the web, and therefore ultimately a good quality of the protection, even without extensive expertise from the assembly operator, in particular as regards the appropriate overlap of two adjacent portions of rolled up tape. The invention makes it possible to limit the manual and random nature of the assembly.

The two sides can form a single piece; they are not necessarily planes, mas can for example be convex, in the form of two half-shells. The web may be closed at or near the longitudinal edge of each panel, by a zipper, a buttonhole, a Velcro® type system, or any other suitable means.

According to one possible embodiment, the inner layer is fixed to the inner face of the protective ply. The fixing can be obtained by stitching or any other suitable means. Thus, the invention provides a one-piece assembly, ready to assemble, which is particularly practical. For further integration of functionality, such an assembly may also include at least one filling fluid introduction nozzle and at least one vent.

Alternatively, the inner layer could form a separate part which is put in place on its own, during a first assembly phase, the web being put in place in a second phase.

The protection system may further include a means for distributing the clamping pressure of the protective ply. The distribution means may be located on the inner face of the protective sheet and be configured to locally impart increased rigidity, without preventing the winding of the protective sheet.

Several possible embodiments of the invention will now be described, by way of nonlimiting examples, with reference to the appended figures: FIG. 1 is a perspective view of a protection system according to one embodiment of the invention. invention, comprising a protective sheet and an inner layer; Figure 2 illustrates the inner layer wrapped around an area to be protected from at least one fluid conduit; FIG. 3 schematically illustrates a first phase of mounting the protection system on the area to be protected; FIG. 4 schematically illustrates a second phase of mounting the protection system on the area to be protected; FIG. S schematically illustrates a third phase of mounting the protection system on the area to be protected; FIG. 6 illustrates the zone to be protected rolled up and clamped in the protective sheet;

° BE2020 / 5897 Figure 7a is a plan view of a clamping device provided with limiting means, according to one embodiment of the invention; Figure 7b is a view of the clamping device of Figure 7a in a first assembly configuration; Figure 7c is a view of the clamping device of Figure 7a in a second assembly configuration; Figure 8 is a schematic view of a clamping device provided with limiting means, according to another embodiment of the invention; Figure 9a is a sectional view of a protection system comprising a tightening device provided with limiting means, according to another embodiment of the invention, before tightening; Figure 9b is a sectional view of the protection system of Figure 9a being tightened; Figure 9c is a sectional view of the protection system of Figure 9a at the end of tightening, in the final state; Figure 10a is a sectional view of a protection system mounted on an area to be protected, in the final state; FIG. 10b is a sectional view of a protection system mounted on an area to be protected, in the final state, the protection system comprising a means for distributing the clamping pressure.

FIG. 1 represents a protection system 1 according to one embodiment of the invention.

Such a protection system 1 is intended to be placed around an area to be protected 2 of at least one fluid conduit 3.

The zone to be protected 2 can comprise a single duct 3, for example following a repair carried out on this duct, or several ducts 3 linked by a connector 4, to protect the connection zone.

In Figures 3, 4 and 5, there are three conduits 3 linked by a connector 4 in the area to be protected 2; in FIGS. 10a and 10b, there are two conduits 3 linked by a connector 4 in the zone to be protected 2. These examples are not limiting.

The longitudinal direction X is defined as being the general direction in which the fluid duct (s) extend, at least in the vicinity of the zone to be protected 2. The terms “longitudinal”, “length” , "Axial" and the like are used with reference to the X direction.

Furthermore, the term "radial" is used with reference to any direction orthogonal to the X direction. The fluid conduits 3 can be electric cables, gas or water pipes, information transmission cables.

The protection system 1 comprises an inner layer 6, which is made of a flexible material, compressible, and permeable to a filling fluid of the protection system 1, that is to say which can be crossed or penetrated by this fluid . For example, the inner layer 6 comprises an open cell foam. As illustrated in Figure 1, the inner layer 6 may be in the form of a piece cut from a panel.

The inner layer 6 is designed to be wrapped around the area to be protected 2, as illustrated in FIG. 2, during a first step of fitting the protection system 1 around the area to be protected 2. The system protection 1 may include means 7 for holding the inner layer 6 in the rolled up position. This is to allow temporary immobilization of the inner layer 6, before carrying out the other steps of fitting the protection system 1, without or with little tightening, so as not to compress the inner layer or only slightly. 6. These retaining means comprise for example several circumferential straps 7, spaced along the longitudinal direction X. Each strap 7 may have one end fixed to the inner layer 6, for example sewn, and a free end provided with means of hooking on itself or on the inner layer 6. Other embodiments are however possible, such as for example straps not attached to the inner layer 6.

The protection system 1 further comprises a protective sheet 10. The protective sheet 10 is flexible, so that it can be wound around the area to be protected, around the inner layer 6.

Depending on the applications, the protective sheet 10 may be made of a material which is waterproof - so as to provide protection against short circuits and / or against corrosion - and / or which is electrically insulating. In addition, the protective sheet 10 preferably has sufficient mechanical strength to withstand external attack, under normal conditions of use, and to contain the filling fluid. The protective sheet 10 may consist of a waterproof canvas, for example of a plasticized canvas.

The protective sheet 10 has two axial edges 13, 14, and two longitudinal edges 15, 16, the edges not necessarily being rectilinear.

Provision can be made for the protective sheet 10 to be non-planar before its implementation, for example preformed into an open cavity, as illustrated in FIG. 1. This is not, however, limiting.

Preferably, the protective sheet 10 comprises two panels 11, 12 which are configured to be placed on either side of the area to be protected 2 and to be assembled to each other with no or little overlap. In other words, with this configuration, the protective sheet 10 is not wound around the area to be protected over several turns, but simply closed around the area to be protected and then optionally assembled to itself at or at the level. vicinity of its longitudinal edges 15, 16. This winding or this fold around the zone to be protected 2 can be made possible by the flexibility of the protective ply 10, and / or by the presence of a zone forming a hinge between the sections 11, 12.

A sealing member 17 may be arranged in the vicinity of each axial edge 13, 14, and preferably in the vicinity of at least one longitudinal edge 16 of the protective ply 10. A barrier can thus be formed, in particular preventing the entry of water into the area to be protected 2 and leakage of filling fluid.

In practice, the inner layer 6 is wound around the area to be protected 2 and held in this position by the holding means 7, then the protective sheet 10 is wound around the inner layer 6. The two windings can be done successively. .

In Figure 2, we see only the inner layer 6 is wound around the area to be protected 2, the protective sheet 10 which is here a separate part, being put in place later, by winding around the inner layer 6.

As a variant, in FIG. 1, the inner layer 6 is fixed to the inner face of the protective ply 10, that is to say the face which will be turned towards the zone to be protected 2. For this purpose, one can sew the protective web 10 and the inner layer 6 together, for example along a substantially median seam line 18. With such a one-piece configuration, it may however remain preferable to wind the inner layer 6 during a first phase, to maintain it via the holding means 7, then to wind the protective sheet 10 during a second phase. .

The protection system 1 is then in the assembled state, as illustrated in figure - 3: the protection system 1 is correctly positioned around the zone to be protected 2, at the end of the assembly steps (at the except for the introduction of filling fluid), and forms a closed enclosure which includes the zone to be protected 2 and into which the filling fluid can be introduced.

The protection system 1 further comprises a device for circumferential tightening of the protective ply 10 in the mounted state, to arrive at a tight state illustrated in FIGS. 4 and € The tightening device may include at least one strap 20 which extends over at least part of the circumference of the protection system 1, in the mounted state. The or each strap 20 further comprises first attachment means 21 which are arranged to cooperate with second attachment means 22 which are arranged on the protection system

1. The second hooking means 22 are for example arranged on the strap 20 (preferably at a location other than the place where the first hooking means 21 are located), or on the protective sheet 10 (preferably on the outside, i.e. the side facing outwards in the mounted position).

According to one possible embodiment, a strap 20 consists of a single strip, one end of which can be attached to the web, the strap wrapping around the protective web 10 and being fixed on itself. According to another possible embodiment, a strap 20 consists of two separate bands, each band having one end attached to the web and the other free end, the two free ends hooking up to each other.

Preferably, a plurality of circumferential straps 20 are provided, spaced along the longitudinal direction X, each strap being provided with hooking means 21, 22. Advantageously, the straps 20 have a large width - for example greater than 5 cm, or even greater than 8 cm - to prevent the formation of bulges during tightening.

The protection system 1 further comprises limiting means configured to limit the degree of circumferential tightening of the ply 10 by means of the clamping device, so that a predetermined minimum distance is provided between the area to be protected 2 and the ply of protection 10.

Thus, in the tight state, as illustrated in FIG. 4, the inner layer 6 forms a lining of sufficient thickness e at any point of the zone to be protected 2, including with regard to sharp angles, to guarantee efficiency. protection system 1.

More precisely, in the zone to be protected 2, the thickness e in the tight state results in a thickness e 'at least equal to e, in the final state, as illustrated in FIG. 5, after introduction fluid or other filling material. The calibrated tightening therefore makes it possible to guarantee a sufficient thickness of the filling fluid. Of course, each of the axial ends of the protection system 1 must be tight around the corresponding duct 3, without minimum thickness, to prevent any leakage of the filling fluid outside the zone to be protected 2. The axial ends must therefore be located at distance from the area to be protected 2.

With reference to FIG. 5, once the calibrated tightening step has been carried out, the filling fluid 19 is introduced into the zone to be protected 2 by a nozzle 8, while the air initially present in the zone to be protected can be evacuated. by at least one vent 9. The filling fluid can be a mastic, a gel, a hardenable resin, and the like. It is preferably waterproof. The introduction of the filling fluid through the nozzle 8 can be carried out by gravity casting, by pressure injection, etc.

According to one embodiment, the filling nozzle 8 and the vents 9 are inserted by the assembly operator into pre-existing orifices made in the protective ply 10, before this ply 10 is wound up. Alternatively, the endpiece 8 filling and the vents 9 are pre-assembled on the protective sheet 10, forming a protection system 1 ready for use for the operator.

An embodiment of the means for limiting the degree of circumferential tightening of the protective ply 10 is described, with reference to FIGS. 7a to 7c.

According to this embodiment, the first hooking means 21 and the second hooking means 22 of a strap 20 are positioned and sized to allow adjustment of the tightening between a predetermined minimum diameter Dmin and a maximum diameter Dmax.

For example, as illustrated in FIG. 7a, the strap 20 comprises, on one side, the first hooking means 21 and, on the opposite face, the second hooking means 22, in the form of loops and hooks. Velcro® type hooking. FIGS. 7b and 7c represent the extreme positions of mutual attachment of the first and second attachment means 21, 22, namely: - an extreme position leading to a maximum diameter Dmax, therefore to minimum tightening (FIG. 7b); - an extreme position leading to a minimum diameter Dmin, therefore to maximum tightening (Figure 7c).

As seen in Figure 7c, further narrowing of the diameter of the strap 20 would not allow the first and second hooking means 21, 22 to cooperate. Thus, greater circumferential tightening than that shown in Figure 7c is not possible.

Another embodiment of the limiting means is illustrated in Figure 8. According to this embodiment, the strap 20 has a fixed length and comprises first hooking means 21 which are arranged to cooperate with second hooking means. hooking 22 arranged on the protection system, in a single hooking position generating a predetermined degree of tightening.

For this purpose, provision can be made for the strap 20 to include: - a strip 23 having one end fixed to the protective sheet 10, for example sewn, and a free end provided with the first hooking means 21; - And a strip 21 having one end fixed to the protective sheet 10, for example sewn, and a free end provided with second hooking means 22; the hooking means 21, 22 forming one a female part and the other a male part of a ratchet system. The mutual latching of the first and second hooking means 21, 22 takes place according to a predetermined, non-adjustable diameter, thereby limiting the circumferential tightening imposed on the protection system 1. FIGS. 9a to 9c illustrate yet another mode of realization of the limiting means, which are not arranged on the clamping device but on the protective ply 10. The limiting means comprise at least one spacer 25 which can be mounted on the inner face of the ply 10 and which has a height h - in a radial direction - predetermined calibrated to prevent excessive tightening. For example, the spacer (s) 25 are at least partially housed in the inner layer 6. Thus, as the operator tightens the clamping means (from FIG. 9a to FIG. 9c), the spacers 25 approach the conduit 3, the connector 4, or possibly another element of the zone to be protected 2, until it comes into abutment against this element, at least in line with the clamping means, that is to say where tightening is most important.

Beyond the position shown in Figure 9c, further tightening is prevented by the fact that at least one spacer 25 abuts against connector 4 - or other element. The height h of a spacer 25 determines the thickness e obtained in the vicinity of the spacer 25.

Figures 10a and 10b show an area to be protected 2 surrounded by a protection system 1 in the final state.

As can be seen in FIG. 10a, the tightening located at the level of the straps 20 along the longitudinal direction X can result, under the pressure of the filling fluid 19, by the appearance of beads between two adjacent straps 20.

To overcome this problem, the protection system 1 may include a means 30 for distributing the clamping pressure of the protective sheet 10. The distribution means 30 may be located on the inner face of the protective sheet 10. It is configured to locally impart increased rigidity, without preventing the winding of the protective ply 10. The distribution means 30 is preferably integral with the protective ply 10. It may consist of a separate plate secured to the ply of protection 10 (for example by gluing, sewing or welding), or of a localized extra thickness of the protective sheet 10, produced in one piece with the sheet.

As can be seen by comparing FIGS. 10a and 10b, the distribution means 30, located at least partly to the right of two adjacent straps 20, makes it possible to locally reduce the formation of beads. This makes it possible in particular to reduce the space to be filled with the filling fluid, the cost of which is relatively high.

Thus, the invention provides a decisive improvement to the prior art.

By providing a tight flexible sheet, the invention allows excellent adaptation to the contours of the zone to be protected, allows a certain flexibility of positioning of the duct (s) (in particular of the zones of entry / exit of these in the system of protection), reduces the types of protection systems required and therefore stocks, reduces the volume of filling fluid, considerably limits the size before installation but also in the final state.

In addition, the tightening limitation means make it possible to prevent excessive tightening, which is detrimental to the quality of the protection provided.

It goes without saying that the invention is not limited to the embodiments described above by way of examples but that it includes all the technical equivalents and the variants of the means described as well as their combinations.

Claims (15)

1. Protection system (1) of an area to be protected (2) of at least one fluid conduit (3), comprising: - an inner layer (6) made of a flexible material, compressible, and permeable to a filling fluid (19) of the protection system (1); - a flexible protective sheet (10); the protection system (1) being configured so that, in the assembled state, the protective sheet (10) is wound around the inner layer (6) itself wound around the area to be protected (2), thus so as to form a closed enclosure which includes the area to be protected (2) and into which the filling fluid (19) can be introduced, the protection system (1) further comprising a circumferential clamping device (20) of the web protection (10) in the mounted state; characterized in that the protection system (1) further comprises limiting means (21, 22, 25) configured to limit the degree of circumferential tightening of the protection sheet (10) by means of the tightening device (20) , and thus limit the degree of compression of the inner layer (6) in the zone to be protected (2), away from the axial ends of the protective ply (10), and thus limit the degree of compression of the layer interior (6) in the area to be protected (2), at a distance from the axial ends of the protective sheet (10), so that a predetermined minimum distance is provided between the area to be protected (2) and the protective sheet ( 10). 2. Protection system according to claim 1, characterized in that the limiting means (21, 22) are arranged on the clamping device (20). 3. Protection system according to claim 1 or 2, characterized in that the clamping device comprises at least one strap (20) which extends over at least part of the circumference of the protection system (1), at the 'mounted state, the strap (20) comprising first hooking means (21) which are arranged to cooperate with second hooking means (22) arranged on the protection system (1), the first and second means of 'hooking (21, 22) being positioned and / or sized to allow adjustment of the tightening between a predetermined minimum diameter (Dmin) and maximum diameter (Dmax). 4. Protection system according to claim 3, characterized in that the first and second hooking means (21, 22) are provided on the strap (20) and comprise one of the loops, the other of the hooks, for form a Velcro® type hook. 5. Protection system according to claim 1 or 2, characterized in that the tightening device comprises at least one strap (20) which extends over at least part of the circumference of the protection system (1), at the 'mounted state, the strap (20) having a fixed length and comprising first hooking means (21) which are arranged to cooperate with second hooking means (22) arranged on the protection system (1), in a single hooking position generating a predetermined degree of tightening. 6. A protection system according to claim 1, characterized in that the limiting means (25) are arranged on the protective sheet (10). 7. A protection system according to claim 6, characterized in that the limiting means comprise at least one spacer (25) mounted on the protection system (1) on the side of the inner face of the web (10), the spacer (25) having a predetermined height (h) and being configured to abut against the duct (3) or another element of the zone to be protected (2), at least in line with the clamping means (20). 8. Protection system according to one of claims 1 to 7, characterized in that the protective sheet (10) is made of a material which is electrically insulating and / or waterproof. 9. A protection system according to one of claims 1 to 8, characterized in that, before its implementation, the protective sheet (10) is non-planar, for example preformed into an open cavity. 10. Protection system according to one of claims 1 to 9, characterized in that the protective sheet (10) comprises two sections (11, 12) configured to be placed on either side of the area to be protected ( 2) and be assembled to each other with zero overlap or which, seen in a transverse plane, is less than 50 °, preferably less than 20 °. 11. Protection system according to one of claims 1 to 10, characterized in that it comprises a sealing member (17) arranged in the vicinity of each axial edge (13, 14) of the protective sheet (10) and preferably in the vicinity of at least one longitudinal edge (15, 16) of the protective ply (10). 12. Protection system according to one of claims 1 to 11, characterized in that the inner layer (6) comprises an open cell foam. 13. Protection system according to one of claims 1 to 12, characterized in that the inner layer (6) is fixed to the inner face of the protective sheet (10). 14. Protection system according to one of claims 1 to 13, characterized in that it comprises holding means (7) of the inner layer (6) in the rolled up position. 15. Protection system according to one of claims 1 to 14, characterized in that it comprises a distribution means (30) of the clamping pressure of the protective sheet (10), said distribution means (30) being located on the inner face of the protective ply (10) and being configured to locally impart increased rigidity, without preventing the winding of the protective ply (10).