PIPE EQUIPPED WITH A DETECTION ELEMENT

Abstract

The invention relates to a pipe (2) including: - a tubular element (3) defining an inner longitudinal passage (5); -a protective element (6) attached onto the outer surface of the tubular element (3) and extending longitudinally in relation to the tubular element (3), the protective element (6) and the tubular element (3) defining a longitudinal receiving passage (9); and -a detection element (12) that is detectable with a detection device. The detection element (12) is linear and includes an electrically conductive core (13) and an electrically insulating sheath (14) that covers the electrically conductive core (13). The detection element (12) extends longitudinally into the receiving passage (9) and is movably mounted longitudinally in relation to the tubular element (3) and the protective element (6).

Description

Pipe equipped with a detection element The present invention relates to a pipeline equipped with a detection element, a method for manufacturing such a pipeline and a method for detecting such a pipeline. For the sake of saving time and costs, but also for safety, it is important to be able to detect the presence of a pipe, and in particular a fluid flow pipe, and to locate it precisely, without digging the ground or destroying structures, during subsequent work. Several methods can be used to detect buried pipes. Electromagnetic detection is the most widely used method. This electromagnetic detection can be carried out using an electromagnetic detector comprising, as is known, a transmitter, such as a current generator, and a receiver. In this case, electromagnetic detection is achieved, firstly, by injecting, using the transmitter of the electromagnetic detector, an electrical signal, which produces an electromagnetic field, into an electrically conductive detection element associated with the pipe to be identified and positioned along its route, via connection boxes installed along the pipe to serve as injection points for the electrical signal, and secondly, by capturing, using the receiver of the electromagnetic detector, the electromagnetic field created by the alternating current flowing in the detection element. In a manner known per se, the detection element is covered by a cylindrical sheath of electrically insulating material, and is fixed to the pipe to be identified using fastening means, such as for example circlips, hook and loop strips, or adhesive strips. Most such mounting methods allow the detection element to move across the outer surface of the pipe to be identified, particularly when the pipe has a circular cross-section. This movement of the detection element can lead to inaccurate positioning, and therefore to inaccurate and difficult detection of the associated pipe. However, given the drastic evolution of accuracy standards in the detection of buried pipes, it is necessary to ensure optimal positioning of the detection element, including after burial of the associated pipe. The present invention aims to remedy these drawbacks. The technical problem underlying the invention is therefore to provide a pipeline which is of simple and economical structure, while ensuring easy and optimal positioning of the detection element and therefore easy detection of the pipeline. To this end, the present invention relates to a pipeline intended to be buried, comprising: - a tubular element defining a longitudinal internal passage, - a protective strip extending longitudinally relative to the tubular element, the protective strip comprising two longitudinal lateral portions fixed to the outer surface of the tubular element, the protective strip and the tubular element defining a longitudinal receiving passage, and - a detection element intended to be detected with a detection device, the detection element being linear and comprising an electrically conductive core and an electrically insulating sheath covering the electrically conductive core, the detection element extending longitudinally in the receiving passage and being mounted movably longitudinally relative to the tubular element and the protective strip, the two longitudinal lateral portions of the protective strip extending on either side of the detection element. Such a pipeline configuration, and more specifically the arrangement of the sensing element in the longitudinal receiving passage partially delimited by the tubular element, ensures an optimal and stable final positioning of the sensing element along the upper generatrix of the associated pipeline, including after burial of the associated pipeline. Thus, the pipeline configuration according to the present invention ensures easy and precise electromagnetic detection of the pipeline. Furthermore, the fact that the detection element is mounted longitudinally in the receiving passage prevents breakage, and in particular tearing, of the protective strip when the pipe is wound onto a reel or drum. Therefore, the pipe configuration according to the present invention allows the detection element to remain in place during the unwinding and laying of the pipe in a trench designed to accommodate it. Moreover, such a mounting of the detection element allows easy access to an end portion of the detection element by tearing a portion of the end of the protective strip using, for example, a simple tool such as a screwdriver or similar, for the purpose of connecting the detection element to a detection element of an adjacent pipe, or to a connection element of a detection terminal. The pipeline configuration according to the present invention, and in particular the fact that it is pre-equipped with the detection element, makes it possible, on the one hand, to reduce installation costs and time, and on the other hand, to facilitate installation, especially in a narrow trench, and also with the aid of a trenching machine. These features also ensure easy installation of the pipeline using pipe jacking and directional drilling. In this patent application, "conduit" means any pipe, tube and sheath intended for the long-distance transport or distribution of a liquid, gas, electricity, or light, or an empty sheath laid pending future use. According to one embodiment of the invention, the internal longitudinal passage is intended for the flow of a fluid, or for the passage of at least one optical fiber and / or at least one electrical cable. According to one embodiment of the invention, the tubular element is flexible. The pipeline may also have one or more of the following characteristics, taken alone or in combination. According to one embodiment of the invention, the detection element extends along the upper generatrix of the tubular element. According to one embodiment of the invention, the longitudinal receiving passage extends over substantially the entire length of the tubular element. According to one embodiment of the invention, the longitudinal receiving passage comprises a first and a second passage openings arranged respectively substantially at the level of the first and second ends of the tubular element. According to one embodiment of the invention, the detection element has a cross-section smaller than the cross-section of the receiving passage. According to another embodiment of the invention, the two longitudinal lateral portions of the protective strip are each fixed to the outer surface of the tubular element by ultrasonic welding. According to one embodiment of the invention, the protective strip is made of a synthetic material, for example, a polymer. The protective strip could be made of a non-woven synthetic material comprising polyethylene fibers, such as high-density polyethylene fibers, and for example, Tyvek (registered trademark). The protective strip could also be made of polypropylene. According to one embodiment of the invention, the detection element is an electrically conductive wire. According to one embodiment of the invention, the tubular element comprises a tubular wall delimiting the internal longitudinal passage, the two lateral portions of the protective strip being fixed to the outer surface of the tubular wall. The tubular wall of the tubular element may, for example, be corrugated or have a smooth outer surface. According to one embodiment of the invention, the electrically insulating sheath is made of polyethylene or polypropylene. According to one embodiment of the invention, the detection element has a rectangular, oval or circular cross-section. According to one embodiment of the invention, the tubular element is made of polyethylene. The present invention further relates to an installation comprising: - at least one pipeline according to the invention, and - at least one connection box comprising at least one connection element electrically connected to the detection element of at least one pipe. According to one embodiment of the invention, the installation comprises at least one detection terminal including at least one connection box. The detection terminal may, for example, conform to those described in documents FR2982889, FR3006061 and FR2997195. The detection terminal may, for example, be a key-operated access control box. According to one embodiment of the invention, the detection terminal comprises an electrically conductive portion electrically connected to the connection element and accessible from outside a structure on which the detection terminal is fixed. Structure includes, in particular, a sidewalk, a roadway, a wall, an access hatch to a technical gallery, a cover, or a manhole. According to one embodiment of the invention, the conduit is a fluid flow conduit or a protective conduit for optical fiber and / or electrical cable, or even for a fluid flow conduit. The present invention also relates to a method for manufacturing a pipeline according to the invention, comprising the steps of: - extrude the tubular element, - place the detection element longitudinally on the outer surface of the tubular element, - lay the protective strip lengthwise on the outer surface of the tubular element so as to cover the detection element, and - fix the longitudinal lateral portions of the protective strip on the outer surface of the tubular element so as to form the longitudinal receiving passage. According to one method of implementing the manufacturing process, the latter includes a cooling step of the tubular element carried out between the extrusion step of the tubular element and the deposition step of the sensing element. According to one method of implementing the manufacturing process, the step of depositing the protective strip is carried out continuously. According to one method of implementing the manufacturing process, the step of fixing the protective strip is carried out continuously. According to one implementation method of the manufacturing process, the protective strip attachment step is performed at the end of the tubular element's manufacturing cycle. Advantageously, the deposition steps are also performed at the end of the tubular element's manufacturing cycle. According to one implementation method of the manufacturing process, the detection element deposition step includes a step of unwinding the detection element from a detection element reel. According to one implementation method of the manufacturing process, the protective tape deposition step includes a step consisting of unwinding the protective tape from a protective tape reel. According to one embodiment of the manufacturing process, the protective strip deposition step consists of depositing the longitudinal lateral portions of the protective strip on either side of the sensing element. According to another embodiment of the manufacturing process, the latter includes a step of longitudinally moving the tubular element, i.e., parallel to its extension direction, and for example along its extrusion direction, during the deposition steps of the sensing element and the protective strip, and during the protective strip fixing step. According to one implementation method of the manufacturing process, the fixing step consists of fixing the longitudinal lateral portions of the protective strip onto the outer surface of the tubular element by ultrasonic welding. According to one method of implementing the manufacturing process, the fixing step is carried out using a sonotrode. According to one implementation method of the manufacturing process, the sonotrode has a resonance frequency between 20 kHz and 70 kHz, and for example 20, 30, 35, 40 or 70 kHz. According to one implementation method of the manufacturing process, the sonotrode exhibits a vibration amplitude between 10 and 120 micrometers. The present invention further relates to a method for detecting an underground pipeline according to the invention, comprising the steps of: - inject an electrical signal into the detection element, - detect the electromagnetic field generated by the detection element. The injection step is advantageously carried out using an electrical signal generator, such as a current generator. According to one embodiment of the detection process, the injection step includes a step of electrically connecting the electrical signal generator to the detection element, and for example, electrically connecting the electrical signal generator to an electrically conductive portion of a detection terminal, said electrically conductive portion being electrically connected to the detection element and being accessible from outside a structure on which the detection terminal is fixed. The detection step is advantageously carried out using an electromagnetic detector. In any case, the invention will be well understood with the aid of the following description with reference to the attached schematic drawing representing, by way of non-limiting example, one embodiment of this pipeline. Figure 1 is a partial perspective view of a pipeline according to the invention. Figure 2 is a cross-sectional view of the pipeline in Figure 1. 1. Figure 3 is a schematic view of the pipeline in Figure 1 during its manufacture. Figure 4 is a schematic view of an installation comprising a pipeline as shown in Figure 1 and a detection terminal. Figures 1 and 2 represent a pipe 2 intended to be buried. Pipe 2 could, for example, be a fluid flow pipe or a protective pipe for fiber optics and / or electrical cable. The pipe 2 comprises a tubular element 3 having a tubular wall 4 defining a longitudinal internal passage 5 intended, for example, for the flow of a fluid, such as a gas or water, and for example rainwater, wastewater, drinking water, or for the passage of at least one optical fiber and / or at least one electrical cable. The tubular wall 4 may, for example, be corrugated or have a smooth outer surface. Furthermore, the tubular element 3 may be made, for example, of polyethylene. The pipe 2 further includes a protective element 6, in the form of a protective strip, fixed to the outer surface of the tubular element 3. The protective element 6 extends longitudinally along the upper generatrix of the tubular element 3. The protective element 6 particularly comprises two longitudinal lateral portions 7, 8 fixed to the outer surface of the tubular element 3 by ultrasonic welding. The protective element 6 is advantageously made of a synthetic material, and more particularly of a polymer. The protective element 6 can be made of a non-woven synthetic material comprising polyethylene fibers, such as high-density polyethylene fibers, and for example, Tyvek (registered trademark). However, the protective element 6 could also be made of another polymer material, such as polypropylene.Protective element 6 may, for example, have a width between 3 and 4 cm. The protective element 6 and the tubular element 3 define a longitudinal receiving passage 9 extending along the entire length of the tubular element 3. The longitudinal receiving passage 9 has first and second passage openings 11 located respectively at the first and second ends of the tubular element 3. The conduit 2 also includes a detection element 12, made in the form of an electrically conductive wire, adapted for detection with a detection device, such as an electromagnetic detector. The detection element 12 extends longitudinally within the receiving passage 9 and is mounted to move longitudinally relative to the tubular element 3 and the protective element 6. The two longitudinal lateral portions 7 and 8 of the protective element 6 advantageously extend on either side of the detection element 12.According to one embodiment of the invention, the detection element 12 has a cross-section smaller than the cross-section of the receiving passage 9. The detection element 12 may have a rectangular, oval, or circular cross-section. The detection element 12 advantageously comprises an electrically conductive core 13 and an electrically insulating sheath 14 covering the electrically conductive core 13. The electrically conductive core 13 may, for example, be made of copper, stainless steel, or another metal, and the electrically insulating sheath 14 may, for example, be made of polyethylene or polypropylene. A method for manufacturing a pipeline 2 according to the invention will now be described. Such a method comprises the following steps: - extrude the tubular element 3, - cool the tubular element 3, - move the tubular element 3 longitudinally, - place the detection element 12 longitudinally on the outer surface of the tubular element 3, - place the protective element 6 longitudinally on the outer surface of the tubular element 3 so as to cover the detection element 12 and such that the longitudinal lateral portions 7, 8 of the protective element 6 extend on either side of the detection element 12, and - fix the longitudinal lateral portions 7, 8 of the protective element 6 on the outer surface of the tubular element 3 by ultrasonic welding so as to form the longitudinal receiving passage 9. According to one method of implementing the manufacturing process, the steps of moving the tubular element 3 and depositing the detection element 12 and the protection element 6 are carried out continuously. According to one implementation of the manufacturing process, the fixing step and the deposition steps are carried out at the end of the manufacturing cycle of the tubular element 3. According to one implementation of the manufacturing process, the deposition step of the detection element 12 includes a step consisting of unwinding the detection element 12 from a reel of detection element 15, and the deposition step of the protection element 6 includes a step consisting of unwinding the protection element from a reel of protection element 16. According to one implementation method of the manufacturing process, the step of fixing the protective element 6 is carried out continuously. According to one embodiment of the manufacturing process, the fixation step is carried out using a sonotrode 17. The sonotrode 17 can have a resonance frequency between 20 kHz and 70 kHz, and for example 20, 30, 35, 40 or 70 kHz, and a vibration amplitude between 10 and 120 micrometers. According to one implementation method of the manufacturing process, the detection element coil 15 and the protection element coil 16 have winding axes perpendicular to the direction of movement of the tubular element 3. A method for detecting a pipe 2 according to the invention will now be described. Such a method comprises the following steps: - provide a detection terminal 18 comprising a connection box 19 equipped with at least one connection element, - strip one end of the detection element 12 belonging to the pipe 2, - electrically connect the bare end of the detection element 12 to the connection element of the detection terminal 18, for example using a section of electrical cable 20, - fix the detection terminal 18 to a structure, such as a sidewalk 24 or a wall 21, - electrically connect an electrical signal generator, such as a current generator, to the connection element of the detection terminal 18, - inject an electrical signal into the detection element 12, via in particular the connecting element, using the electrical signal generator, and - detect the electromagnetic field generated by the detection element 12 using an electromagnetic detector in order to detect and follow the pipeline 2. According to one implementation method of the detection process, the detection terminal 12 includes an electrically conductive portion 22 electrically connected to the detection element, and the fixing step of the detection terminal 18 is carried out in such a way that the electrically conductive portion 22 is accessible from outside the structure. According to one implementation method of the detection process, the injection step includes a step consisting of electrically connecting the electrical signal generator to the electrically conductive portion 22 of the detection terminal. According to another method of implementing the detection process, the fixing step consists of fixing the detection terminal 18 near a gas meter box 23, water meters or any other flush-mounted device. According to one implementation variant of the detection method, the bare end of the detection element 12 could be electrically connected to a box placed in an inspection chamber, and the electrical signal could then be injected into the detection element 12 via the box. According to yet another implementation variant of the detection method, the bare end of the detection element 12 could be left pending, and the electrical signal could then be injected directly into the detection element 12 from its bare end. As can be understood, the invention is not limited to the single form of execution of this pipeline 2, described above by way of example, but on the contrary encompasses all variants of its implementation.

Claims

DEMANDS 1. Pipeline (2) intended to be buried, comprising: - a tubular element (3) defining an internal longitudinal passage (5), - a protective strip (6) extending longitudinally relative to the tubular element (3), the protective strip (6) comprising two longitudinal lateral portions (7, 8) fixed to the outer surface of the tubular element (3), the protective strip (6) and the tubular element (3) defining a longitudinal receiving passage (9), and - a detection element (12) intended to be detected with a detection device, the detection element (12) being linear and comprising an electrically conductive core (13) and an electrically insulating sheath (14) covering the electrically conductive core (13), the detection element (12) extending longitudinally in the receiving passage (9) and being mounted movably longitudinally relative to the tubular element (3) and the protective strip (6), the two longitudinal lateral portions (7, 8) of the protective strip (6) extending on either side of the detection element (12).

2. Pipeline according to claim 1, wherein the sensing element (12) has a cross-section smaller than the cross-section of the receiving passage (9).

3. Pipeline according to any one of claims 1 or 2, wherein the two longitudinal lateral portions (7, 8) of the protective strip (6) are each fixed to the outer surface of the tubular element (3) by ultrasonic welding.

4. Conduit according to any one of claims 1 to 3, wherein the protective strip (6) is made of synthetic material, and for example of polymer material.

5. Pipeline according to claim 4, wherein the protective strip (6) is made of non-woven synthetic material comprising polyethylene fibers, such as high-density polyethylene fibers.

6. Conduit according to any one of claims 1 to 5, wherein the protective strip (6) is made of Tyvek.

7. Installation including: - at least one pipeline (2) according to any one of the claims 1 to 6, and - at least one connection box (19) comprising at least one connection element electrically connected to the detection element (12) of at least one pipe (2).

8. A method for manufacturing a pipeline (2) according to any one of claims 1 to 6, comprising the steps of: - extrude the tubular element (3), - place the detection element (12) longitudinally on the outer surface of the tubular element (3), - place the protective strip (6) longitudinally on the outer surface of the tubular element (3) so as to cover the detection element (12), and - fix the two longitudinal lateral portions (7, 8) of the protective strip (6) on the outer surface of the tubular element (3) so as to form the longitudinal receiving passage (9).

9. Manufacturing method according to claim 8, wherein the fixing step consists of fixing the two longitudinal lateral portions (7, 8) of the protective strip (6) onto the outer surface of the tubular element (3) by ultrasonic welding.

10. A method for detecting a pipeline (2) according to any one of claims 1 to 6, comprising the steps of: - inject an electrical signal into the detection element (12), - detect the electromagnetic field generated by the detection element (12).