Traceable power cable and method

Abstract

It is disclosed a power cable comprising at least one conductor and a hollow tube at least partially filled with a traceable material. The traceable material comprises a tracer associated with a uniquely identifiable code and is in a liquid or gel form. The tracer may comprise one or more of: coded synthetic DNA particles, a fingerprint of one or more trace materials, microdots containing a code written thereon. The tracer may also comprise radio-frequency identification, RFID, tags.

Claims

1. A power cable comprising at least one conductor and a hollow tube at least partially filled with a traceable material, wherein said traceable material comprises a tracer associated with a uniquely identifiable code and wherein said traceable material is in a liquid or gel form wherein said hollow tube is an independent element.

2. The power cable according to claim 1, wherein said tracer comprises one or more of: coded synthetic DNA particles, a fingerprint of one or more trace materials, microdots containing a code written thereon.

3. The power cable according to claim 1, wherein said tracer comprises radio-frequency identification, RFID, tags.

4. The power cable according to claim 1, wherein said hollow tube has an inner diameter comprised between about 1 mm and about 10 mm.

5. The power cable according to claim 1, wherein said hollow tube has an outer diameter substantially corresponding to a dimension of an element of said power cable.

6. The power cable according to claim 1, wherein the total conductor cross section is equal to or greater than 120 mm.sup.2.

7. The power cable according to claim 1, wherein said hollow tube is an independent element in between said at least one conductor of the cable.

8. The power cable according to claims 1, wherein said outer diameter substantially corresponds to a diameter of a cross section of said at least one conductor.

9. The power cable according to any of claim 1, wherein said at least one conductor is a multiwire conductor and said hollow tube is part of said multiwire conductor.

10. The power cable according to claim 9, wherein the cross section of said at least one conductor is equal to or greater than 120 mm.sup.2.

11. The power cable according to claim 9 wherein said outer diameter substantially corresponds to a diameter of a wire or a bunch of wires of said multiwire conductor.

12. The power cable according to claim 1, wherein said hollow tube is obtained by extrusion.

13. The power cable according to claim 1, wherein said hollow tube is made of PVC.

14. A method for providing a traceable power cable comprising providing at least one conductor and a hollow tube within the cable, and filling the hollow tube with a traceable material, wherein said traceable material comprises a tracer associated with a uniquely identifiable code and wherein said traceable material is in a liquid or gel form, wherein said filling the hollow tube with a traceable material having a tracer comprises filling an independent element of the power cable.

15. The method according to claim 14, wherein said filling is performed at an installation site.

16. The method according to claim 14, wherein said filling the hollow tube with a traceable material having a tracer comprises filling the hollow tube with a traceable material comprising one or more of: coded synthetic DNA particles, a fingerprint of one or more trace materials, microdots containing a code written thereon.

17. The method according to claim 14, wherein said filling the hollow tube with a traceable material having a tracer comprises filling the hollow tube with a traceable material comprising radio-frequency identification, RFID, tags.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become fully clear by reading the following detailed description, to be read by referring to the accompanying drawings, wherein:

(2) FIG. 1 is a cross section view of a cable according to a first embodiment of the present invention;

(3) FIG. 2 is a cross section view of a cable according to a second embodiment depicted in FIG. 1;

(4) FIG. 3 is a cross section view of a cable according to a third embodiment of the present invention;

(5) FIG. 4 is a cross section view of a cable according to a fourth embodiment of the present invention;

(6) FIG. 5 is a cross section view of a cable according to a fifth embodiment of the present invention; and

(7) FIG. 6 is a cross section view of a cable according to a sixth embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(8) In the present description and claims, unless otherwise specified, all the numbers and values should be intended as preceded by the term about.

(9) The present invention provides a power cable comprising a hollow tube adapted to be filled at least partially with a material comprising a tracer with a uniquely identifiable code. This material will be referred to in the present description and in the claims as traceable material. The hollow tube, according to the present invention, may be positioned within the power cable as replacing a core element (namely, a power or control conductor) or another element in any position within the cable, either in the center of the cable or in each layer of core elements within the cable. In this case, the hollow tube is preferably integrated with the core elements during stranding of the core elements. Alternatively or in addition, the hollow tube may replace a single wire or a bunch of wires of a power or control conductor. Moreover, alternatively or in addition, the hollow tube may be positioned in an interstice between any two or more cable elements, for instance between two or more power and/or control conductors in the cable, and/or between the power and/or control conductors and a sheath of the cable, and/or between the power and/or control conductors and a central element of the cable.

(10) The traceable material is preferably in the form of a liquid or a gel and it may be water-based.

(11) The tracer preferably comprises coded synthetic DNA particles.

(12) Alternatively, the tracer preferably comprises a radio-frequency identification (RFID) tag or the like. As it is known, RFID uses electromagnetic fields to automatically identify and track tags attached to objects and containing electronically stored information. More preferably, the tracer comprises a plurality of RFID tags.

(13) Alternatively, the tracer preferably comprises a fingerprint of one or more trace materials, or microdots containing a code written thereon.

(14) According to even alternative embodiments of the present invention the tracer comprises a combination of two or more of the coded synthetic DNA particles, the RFID tag(s), the fingerprint of one or more trace materials and the microdots containing a code written thereon.

(15) Moreover, optionally, the traceable material may contain also fluorescent components adapted to be identifiable under a source of light, e.g. a source of ultraviolet light.

(16) The uniquely identifiable code associated with the tracer may contain information regarding one or more of: an owner of the cable, a location or installation site, a cable type, a year of construction, a manufacturer identifier. Other information may be coded in the uniquely identifiable code which provides identification data of the cable.

(17) The dimensions of the hollow tube are selected on the basis of the cable construction. According to the present invention, the hollow tube has an inner diameter whose value is selected preferably within a range of 1 mm to 10 mm. Preferably, the inner diameter is selected such that the traceable material may be easily filled throughout the entire length of the tube and that the traceable material is enough to allow identification of the cable. On the other side, the inner diameter is preferably selected such that the amount of traceable material is not too high, since in this case it would determine excessive expenses.

(18) According to the present invention, the outer diameter of the hollow tube may vary on the basis of the cable construction. Preferably, the outer diameter of the hollow tube substantially correspond to a dimension of a cable element, which the hollow tube may replace. This element may be either the dimension of a conductive power or control core, or the dimension of a single wire or bunch of wires in a conductive core. Alternatively, the hollow tube may have the dimension of another element of the cable, such as a central element. According to the cable construction, the hollow tube may, for instance, replace a conductor or a single wire and hence the outer diameter may substantially correspond to, respectively, the diameter of the cross section of the conductor or the diameter of the single wire. On the contrary, the inner diameter of the hollow tube may have a pre-determined value, irrespective of the cable construction. This advantageously implies that connectivity of the hollow tubes may be easily achieved by using the same connectivity technology for different cables. Moreover, the same amount of traceable material is advantageously used irrespective of the cable construction.

(19) The hollow rube is preferably obtained by extrusion. The material of the hollow tube may be PVC (polyvinylchloride).

(20) In the following description, a number of different embodiments of the present invention will be described.

(21) FIG. 1 schematically shows a cross section of a power cable 1 according to a first embodiment of the present invention. Cable 1 is preferably a multicore power cable. Preferably, the cable 1 comprises a number of core elements 11, comprising:

(22) a power or earth conductor 111 coated by a respective insulating sleeve 112, wherein the conductor 111 may comprise a number of stranded conductive wires; or

(23) a control or signaling element (e.g. one or more twisted pairs or quads with screen and insulation), or an optical element comprising one or more optical fibers and mechanical protection; or

(24) a suspension element (e.g. Kevlar thread),

(25) or any combination thereof.

(26) Preferably, the cable 1 also comprises a sheath 12. The cable 1 may comprise other layers above the sheath 12 (e.g. a metallic screen and/or an external sheath), which are not shown in FIG. 1 as they are not relevant to the present description.

(27) The material of each conductor 111 is preferably one of: copper, aluminum, copper alloy. Each insulating sleeve 112 and the sheath 12 may be made of any insulating material such as one of the following materials: PVC (polyvinylchloride), rubber, XLPE (cross-linked polyethylene), PUR (polyurethane), PTFE (polytetrafluoroethylene), ETFE (ethylene tetrafluoroethylene).

(28) The cable 1 further preferably comprises a hollow element 13 in the form of a hollow tube adapted to be filled at least partially with the traceable material described above. The material of the hollow tube 13 is preferably chosen so that it is heat resistant and the material of the hollow tube 13 may be PVC (polyvinylchloride). The hollow tube 13 has preferably an inner diameter comprised between about 1 mm and 10 mm. According to this first embodiment of the invention, the outer diameter of the hollow tube 13 is substantially equal to the diameter of a core element 21.

(29) In the exemplary cable of FIG. 1, the hollow tube 13 is positioned substantially at the center of the cable 1.

(30) FIG. 2 schematically shows the cross section of a power cable 2 according to a second embodiment of the present invention. Similarly to the cable 1 of FIG. 1, the cable 2 according to this second embodiment is a multicore power cable comprising a number of core elements 21 comprising:

(31) a power or earth conductor 111 coated by a respective insulating sleeve 112, wherein the conductor 111 may comprise a number of stranded conductive wires; or

(32) a control or signaling element (e.g. one or more twisted pairs or quads with screen and insulation), or an optical element comprising one or more optical fibers and mechanical protection; or

(33) a suspension element (e.g. Kevlar thread),

(34) or any combination thereof.

(35) The cable 2 preferably comprises also a sheath 22. The cable 2 further comprises a central element 24 which may be, for instance, a strength member, or a rubber element, or a paper core. The materials of the conductors 211, the sleeves 212 and the sheath 22 are the same as already mentioned above for cable 1 of FIG. 1.

(36) Further, preferably, the cable 2 comprises a hollow tube 23 adapted to be filled at least partially with the traceable material, as already described above. Preferably, according to this embodiment, the hollow tube 23 replaces one of the core elements 21 in cable 2 and has the same size of any core element 21.

(37) FIG. 3 schematically shows the cross section of a core element 31 for a power cable according to a third embodiment of the present invention. The core element 31 comprises a multiwire conductor, preferably having a cross section equal to or greater than 120 mm.sup.2, comprising a number of stranded conductive wires 311. The core element 31 further comprises a sleeve 312. The materials of the conductor 311 and the sleeve 312 are the same as already mentioned above for cable 1 of FIG. 1.

(38) Further preferably, the core element 31 comprises a number of hollow tubes 33 adapted to be filled at least partially with the traceable material.

(39) For instance, in a multiwire conductor with class 2 stranded wires DIN VDE 0295 (2005-09) with a cross section of 185 mm.sup.2, the number of individual wires may be 37 each having a diameter nearly equal to 2.52 mm. In this case, one or more hollow tubes 33 may replace one or more wires of the conductor. Therefore in this case, the hollow tube 33 has an outer diameter nearly equal to the diameter of a single wire. In order to have the same conductor cross section area, replacing one or more wires in the conductor with the hollow tubes requires that the cross section area of the other wires is enlarged.

(40) According to another example, a conductor with class 5 stranded wires may have a cross section equal to 120 mm.sup.2, and each wire may have a diameter of about 0.39 mm. In this case, bunches of 50 to 48 wires may be manufactured in layers, one bunch at the center of the conductor, 6 bunches in a second layer, and 12 bunches in a third layer. The diameter of a single bunch of 500.39 mm is approximately 3.16 mm. One or more bunches may be replaced by one or more hollow tubes 33, in any layer. In order to have the same conductor cross section area, replacing one or more bunches in the conductor with the hollow tubes requires that the number of the wires in the other bunches is increased.

(41) FIG. 4 schematically shows the cross section of a power cable 4 according to a fourth embodiment of the present invention. Similarly to the cable 1 of FIG. 1, the cable 4 according to this fourth embodiment is a multicore power cable comprising a number of core elements 41, 41 (e.g. four power conductors 41 and one earth conductor 41 in the exemplary cable of FIG. 4), each comprising a conductor 411 coated by a respective sleeve 412, and a sheath 42. The materials of the conductors 411, the sleeves 412 and the sheath 42 are the same as already mentioned above for cable 1 of FIG. 1.

(42) Further, preferably, the cable 4 comprises one or more hollow tubes 43 adapted to be filled at least partially with the traceable material, as already described above. Preferably, according to this embodiment, the hollow tubes 43 are located at interstices among the core elements 41. For instance, as depicted in FIG. 4, a hollow tube 43 may be positioned at the center of the cable, and/or a hollow tube 43 may be positioned in an interstice between the core elements 41 and the sleeve 42. The cable 4 may further comprise a supporting member 45. The cable 4 may comprise other elements 46 that are not relevant to the present description, such as for instance optical fiber elements.

(43) FIG. 5 schematically shows the cross section of a power cable 5 according to a fifth embodiment of the present invention. The power cable 5 of FIG. 5 is similar to the power cable 2 of FIG. 2. Therefore, a detailed description of the cable elements is not repeated herein after. According to this fifth embodiment, one or more hollow tubes 53 are positioned in the interstices between the central element 54 and the core elements 51. Alternatively, the power cable may comprise both a hollow tube replacing one or more of the core elements as shown in FIG. 2 and hollow tubes placed in the interstices between the central element and the core elements as shown in FIG. 5.

(44) FIG. 6 schematically shows the cross section of a power cable 6 according to a sixth embodiment of the present invention. Similarly to the cable 1 of FIG. 1, the cable 6 according to this sixth embodiment is a multicore power cable comprising a number of core elements 61, 61 (e.g. three power conductors 61 and one earth conductor 61 in the exemplary cable of FIG. 6), each comprising a conductor 611 coated by a respective sleeve 612, and a sheath 62. Further, preferably, the cable 6 comprises one or more hollow tubes 63 adapted to be filled at least partially with the traceable material, as already described above. Preferably, the hollow tubes 63 are located at interstices among the core elements 61. For instance, as depicted in FIG. 6, a hollow tube 63 may be positioned nearly at the center of the cable, and/or a hollow tube 63 may be positioned in an interstice between two core elements 61 and the sleeve 62. The cable 6 may further comprise an optical fiber element 66.

(45) As already mentioned above, according to the present invention, the liquid with the tracer can be filled in the hollow element of the cable after the cable installation. This avoids the risk of contaminating the cable production site or the risk of cross-contamination of the cables from consecutive production runs on the same manufacturing machine.

(46) Moreover, according to the present invention, when the cable is cut by a thief, the hollow element containing the liquid with the tracer is also cut so that the liquid leaks from the hollow element. In this case, the liquid flows on the conductors and the other elements of the cable and sticks on them as well as on the objects that are come into contact with it, such as, for instance, the clothes or the skin of the thieves. The fluorescent components that may be provided in the liquid composition containing the tracer are immediately and clearly identifiable by official authorities such as the police or other authorized institutions under e.g. UV light, so as to get a straightforward indication of possible theft.

(47) Then, advantageously, the stolen conductors are immediately identifiable by decoding the uniquely identifiable code that provides information such as the owner of the cable, the installation site, the manufacturer identity and so on. The theft can be clearly verified. Moreover, also the objects used for the theft and the individuals involved in the theft may come into contact with the liquid composition and hence be connected to the robbery in a straightforward manner. This provides a very strong deterrence measure to prevent cable thefts.

(48) As said above, according to embodiments of the present invention, the tracer could comprise RFID tag(s). An advantage of the embodiment with RFID tags is that such tags do not have to be scanned manually or oriented in a certain way to be readable.

(49) One tag which can be used in connection with the present invention is -chip. Like other passive RFID chips, -chip operates simply and requires no batteries or power supply. When it is embedded in an item along with an attached antenna (usually a filament like strip), it will respond to microwaves (e.g. 2.45-gigahertz microwaves) from a scanner by reflecting back a unique ID number (e.g. a 128-bit ID number) stored in its read only memory (ROM). The scanner then checks the number against a databasewhich can be anywhere in the worldto immediately authenticate the item containing the chip. The chip could be of few millimetres (for instance 3 or 4 mm) on a side and 0.1 mm to 0.25 mm thick.

(50) According to the present invention, the cable 1, 2 may also be marked with an additional exterior marking applied on the sheath 12, 22 indicating that the cable 1, 2 is identifiable. The marking is preferably a string of alphanumeric characters having a meaning immediately understandable by a human individual, such as DNA secured. Advantageously, this marking is immediately apparent to any individual that handles the cable and therefore provides an additional deterrence measure to prevent stealing of the cable.

(51) Possibly, the exterior marking can be applied or printed in a position indicative of the position of the RFID tag. For instance, having reference to FIG. 1.1, the marking 116 can be substantially opposite with respect to the RFID tag 113.

(52) The present invention also relates to a method for providing a traceable power cable as described above. The method preferably comprises providing a cable comprising one or more core conductors 11, 21, 31, 41, 51, 61 and at least one hollow tube 13, 23, 33, 43, 53, 63 as described above. According to embodiments of the present invention, in a multicore cable, such as cable 1 of FIG. 1 or cable 2 of FIG. 2, the hollow tube 13, 23 is an independent element of the power cable. Preferably, the hollow tube 13, 23 is an independent element among the conductive cores of the cable. According to other embodiments of the present invention, one or more hollow tubes 33 may also be part of a multiwire conductor for a conductive core of an energy transmission cable, as exemplarily depicted in FIG. 3. According to even other embodiments of the present invention, as depicted in FIGS. 4 and 5, one or more hollow tubes 43, 53, 63 may be inserted in the interstices among the conductive cores of the power cable or between the conductive cores and other elements of the cable (e.g. a central element or the sheath of the cable).

(53) The method further preferably comprises filling the hollow tube(s) 13, 23, 33, 43, 53, 63 with the traceable material, as described above. The hollow tube(s) 13, 23, 33, 43, 53, 63 may be filled with the traceable material before or during the installation of the cable, namely before or during laying down the cable at the installation site. Alternatively, the hollow tube(s) 13, 23, 33, 43, 53, 63 may be filled with the traceable material after the installation. Filling the hollow tube(s) 13, 23, 33, 43, 53, 63 with the traceable material may be performed by using a device with positive or negative pressure. Moreover, valves may be inserted at both ends of the hollow tube for filling the hollow tube and closing its ends.