A remanent marked electric cable

Abstract

Electrical cable comprising a metallic conductor and at least an external extruded covering, such external extruded covering comprising a first marking, wherein the metallic conductor comprises a second marking, first and second markings defining a remanent marking of the electrical cable.

Description

[0001] TITLE

[0002] A remanent marked electric cable

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to electric cables comprising at least a metallic conductor and an external covering surrounding it. The invention aims to provide a remanent marking on such cables whatever the external wear and tear of the cable is. The invention brings a solution against the problem of identification and traceability of cables at any time during its useful life, including for property right information.

[0005] BACKGROUND OF THE INVENTION

[0006] It is known in the art, from EP-2706540, a cable including a marking device consisting of pairs (Pl, P2, P3) of adjacent identical length values, the pairs respectively being spaced apart by a unit of length and being made up of increasing values, this marking device being designed to allow the cutting of a segment with length L of cable wound around a cable drum, such that said marking device also includes two different marks on either side of each pair of values.

[0007] This solution is interesting for a cable user needing to cut cable to an exact length. The aim of that solution is to print a lot of marking onto a single cable, and to provide at the same time the cutting location for users willing to obtain a determined centimeters or meters of cables without the need of an extra device to measure it.

[0008] In the art when cables are provided to clients who intend to use those electric cable into huge buildings infrastructure, there is a need for those clients to be provided with an exact length of reeled cable that they may unreel on purpose.

[0009] Up to now, cable manufacturers were using brand new cables directly from a reeled cable provided by a factory. Marking on cables can be erased or lost due to possible damage to the external covering during cable installation or even due to the environmental conditions over time. Moreover, due to installation and recollection processes, marking may disappear on those occasions.

[0010] To prevent and identify theft and fraud such as fake branding of cables or illegal marketing of cables by third parties, there is a need for a remanent marking. Such remanent marking is necessary to identify major characteristics of the cable over time, such as voltage class, conductor cross-section, cable manufacturer, and any other traceability information, which also cannot be easily erased.

[0011] In numerous occasions, there is a need to abandon an electrifying plan, and to collect already used cables, especially when such cables could still be reused. Cables that may be reused need to be compliant with regulations. Before testing if a used cables would comply with regulations, it is important to collect information about its age, production cycle, material, manufacturer, and many other traceability information. That information helps to determine if the cable would be worth it to go through quality testing to bring it back into the market, or if it shall be thrown away.

[0012] To safe recollection of cables and their second use or to estimate the value and metal content, there is a need for a cable manufacturer or user to clearly identify cables.

[0013] The present invention aims to provide an upgraded solution to marking problems by offering an electrical cable comprising a metallic conductor and an external sheath or any external covering, such external covering comprising a first marking, wherein the metallic conductor comprises a second marking, first and second markings defining a remanent marking of the electrical cable. Preferably the external covering is an electrically insulating layer or mechanical covering adjacent to the metallic conductor.

[0014] The electrical cable of the invention is preferably constructed for low voltage, medium voltage or high voltage applications. In some embodiment, the electrical cable may be waterproof, and comprises water blocking means to avoid water penetration.

[0015] Preferably, the external covering may be composed by one or more extruded layers. The one or more extruded layers may be composed by thermoplastic compounds or thermoset compounds or mixture thereof. When the external covering comprises several layers, the external covering comprises at least a semiconductive layer and an external layer, such that the semiconductive layer is applied between the metallic conductor and the external layer of the external covering.

[0016] According to a preferred embodiment of the invention, the metallic conductor is composed by one or more insulated conductors, with thermoplastic or thermoset insulation, and an over sheath with thermoplastic or thermoset compound.

[0017] According to another preferred embodiment of the invention, the electrical cable comprises a central core and an outer layer of individual wires twisted around a longitudinal axis of the core, wherein the second marking is provided along the longitudinal axis on at least two adjacent individual wires. Even when the first marking is partially erased, the second marking remains available to provide traceability information.

[0018] Individual wires are generally wounded around the longitudinal axis with an angular wire inclination such that the marking is provided along a section of the cable such that the section forms a marking angle compared to the longitudinal axis inferior to the angular wire inclination.

[0019] For example, the second marking is applied on an external layer of the metallic conductor or on an internal layer of the metallic conductor or even on the central wire.

[0020] According to some embodiments of the invention, the second marking may be applied over an insulation of the metallic conductors and the first marking is applied over the external covering of cable. The first and second markings may each comprise at least two distinct characters. For example, two characters of a marking form a row. Each character is at least defined by height and width, such height and width being superior to individual wires diameter, and inferior to the metallic conductor diameter and inferior to the electric cable diameter.

[0021] More preferably, character height and width are at least 25% of the individual metallic wires diameter of the metallic conductor, and less than 50% of the metallic conductor diameter.

[0022] Preferably, at least one layer of individual wires defines an outer surface, an inner surface of the external covering being adjacent to such outer surface of the layer of individual wires.

[0023] Preferably several first markings are performed all along the outer surface of the external covering. Preferably, several second markings may be performed all along an outer surface of the metallic conductor at a substantially constant second interval. That second marking provides a second cross-checked information to guaranty about the exact length of cable provided to client, without the need to control mass of the delivered cables, even for reused cables.

[0024] For example, the first interval is derived from the second interval. A correlation between first and second constant intervals values may be information provided by the first marking. Definition of a correlation between first and second markings provides additional information to check the reliability of the information relative to the manufacturer of the cable, and the reliability of the information provided in general with that remanent marking.

[0025] Thanks to the invention, cable manufacturers may easily check the length of cables they received at their facilities, whatever the exact external shape of the reeled cable is, and without the need of a weighting check procedure. Weight checking is difficult as it is needed to weigh the reeled cable and its support, and to weigh the support when the cable has been fully unreeled. This weighting check procedure only provides information at a time the cable manufacturer already used the full length of cable in its manufacturing process. The invention aims to provide efficient marking that provides early certainty to the client's facilities, to secure their building processes. This continued marking also allows a guaranty about the exact length of cable provided to clients, without the need to control mass of the delivered cables, even for reused cables.

[0026] Preferably, first and second markings are at least partially superimposed along the longitudinal central axis of the electrical cable. This allows clients to limit destructive inspection of cables with only a short length of cables to strip when compiling information of first and second markings.

[0027] Preferably, the first and second markings are either inkjet or laser printed on at least two adjacent individual wires. Alternatively, first and second markings may also be engraved, such as by high or low relief engraving methods. First and second markings are represented in Figure 2 as being printed on the same angular area of the electrical cable, but various respective locations are available for respectively the first and second markings. Angular shift between the first and second markings may be additional information creating the remanent marking.

[0028] The metallic conductor may be flexible or rigid. The metallic conductor may comprise copper, aluminum, or mixture thereof. The cross section of the metallic conductor may either be circular or non-circular. The metallic conductor may for example be tinned, silver-plated or nickel-plated copper or aluminum conductor.

[0029] Individual wires are wounded around the longitudinal axis of the cable with an angular wire inclination such that the marking is provided along a section of the cable such that the section forms a marking angle compared to the longitudinal, that marking angle being inferior to the angular wire inclination. For example, marking angle may also be a null angle compared to the longitudinal axis.

[0030] Alternatively, the metallic conductor may be a single wire.

[0031] Marking may include metering information such that the reeled cable is provided with the lowest metering value close to the support, and the marking with the highest metering value being the most external part of that reeled cable. For example, markings may be provided every meter all along the cable.

[0032] The invention also provides a reeled cable comprising a support and an electrical cable according to the invention, the electrical cable being reeled in successive layers around the support.

[0033] Finally, the invention also provides a reeling process of a cable wherein an electrical cable according to the invention, wherein the second marking is provided by an inkjet printer after twisting the individual wires to form the layer of adjacent individual wires around the central core, and before extruding the external covering around the layer of individual wires, and further printing of the first marking prior to final reeling operation of the electrical cable on the support.

[0034] A further object of the present invention is to seek to solve one or more of the problems or drawbacks according to prior art.

[0035] Advantageous embodiments of the present invention are indicated in the dependent claims.

[0036] Other objects and advantages of the present invention will more fully appear from the following detailed description taken in connection with the accompanying drawing, wherein:

[0037] Figure 1 is an external view of a cable along with the invention, the cable being partially stripped from its outer covering.

[0038] Figure 2 is an enlarged view of a second marking of a metallic conductor layer of an electrical cable along the invention.

[0039] SUMMARY OF THE INVENTION

[0040] An electrical cable 1 of the invention is a stranded cable comprising a plurality of metallic wires 10, for example of aluminum, copper, or other metals or alloys of combinations thereof, where the metallic wires are bundled or wrapped together around a central core to form at least an external layer of adjacent metallic wires 10, such that the external layer of metallic wires 10 is covered by an insulative outer covering 11. The stranded cable 1 may be manufactured in a variety of configurations, where the plurality of metallic wires is bundled or wrapped together to form a bunch stranding configuration, a concentric stranding configuration, an unilay stranding configuration or a rope laying configuration.

[0041] Furthermore, the stranded cable 1 may have a generally circular crosssection but also applied to a sector conductor (non circular conductor). Preferably the external cross section of such electrical cable is provided by adjacent external surfaces of wires placed in contact one to another and stranded in an helical manner around the central core such that there is enough metallic wires to cover the central core all over with adjacent wires.

[0042] Metallic wires 10 being of a generally circular cross section, those metallic wires are tangentially contacting each other to define a continuous outer surface of the metallic conductor.

[0043] According to another embodiment of the invention (not shown), the metallic conductor may either be a single bare conductor.

[0044] The electrical cable 1 according to the embodiment of Figures 1 and 2 of the invention is a multi-wire electrical conductor assembly. The central core may be either identical to metallic wires forming the external surface of the metallic conductor, or in an alternative be a carbon wire.

[0045] For example, the electrical cable according to the present invention includes nineteen individual metallic wires 10 arranged in an inner layer of wires and an outer layer of wires. A core wire is provided which has a straight longitudinal extent, and for example six wires are closely wound in helical fashion about the core wire to provide a centrally arranged cluster of seven wires having a circular cross-section, these six wires defining a first inner layer, and the remaining twelve wires of such arrangement are closely wound in helical fashion around the periphery of the centrally arranged cluster of wires. In forming the electrical cable, it is preferable to first wind the wires about the core wire, and then wind the second layer of wires about the first wire with the same direction of helical twist. However, all wires could be wound simultaneously, and the outer wires can be wound with a helical twist opposite that of wires. Preferably all individual wires are identical metallic wires. Cross section of each individual wire is between 0.15 mm2and 20 mm2.

[0046] The electrical cable extends along a longitudinal axis X. It presents an outer diameter "De", and the external layer of metallic wires presents an outer diameter "D" between 2 and 40 mm.

[0047] Each individual wire has an external diameter "d" between 0.05 and 12 mm.

[0048] Wires are helically wounded along the X axis, such that wires defining part of the external surface of the electrical cable present an angle A with such longitudinal axis.

[0049] Marking provided on the cable may comprise at least one row of character. A row of character may comprise at least two characters. A character is, by definition, a graphic symbol used in writing or printing. Characters may be any kind of sign or symbol, including letters, figures and / or Unicode set of characters.

[0050] First markings 12 are provided on the outer covering 11 according to a regular pattern provided by a constant interval II between adjacent first markings. Prior the outer covering is extruded onto the metallic conductor 10, a second marking 13 is provided to the external surface of the metallic conductor 10, and especially on the external layer of metallic conductors.

[0051] A constant interval 12 is set between two adjacent second markings 13 of the metallic conductor 10, such that the second interval value 12 is prescribed by the first marking II itself or derived from the value of a constant interval between first markings 12.

[0052] Preferably dimensions of the characters are in length "I" along the X- axis and Heigh "H" perpendicular to X-axis are set such that Hl is a height of a character of the first marking 12 and H2 is a height of a character of the second marking 13

[0053] H2 > 1.1 * d * tan(A) I sin(A)

[0054] H2 < 0.7 * D

[0055] Hl < 0.7 * De

Claims

CLAIMS1. Electrical cable comprising a metallic conductor and at least an external covering, such external covering comprising a first marking, wherein the metallic conductor comprises a second marking, first and second markings defining a remanent marking of the electrical cable.

2. Electrical cable according claim 1 wherein the external covering is composed by one or more extruded layers.

3. Electrical cable according claim 2 wherein the one or more extruded layers can be composed by thermoplastic compounds or thermoset compounds or mixture thereof.

4. Electrical cable according claim 3 wherein a semiconductive layer is applied between the metallic conductor and the extruded external covering.

5. Electrical cable according claim 1 wherein the metallic conductor is composed by one or more insulated conductors, with thermoplastic or thermoset insulation, and an over sheath with thermoplastic or thermoset compound.

6. Electrical cable according to one of preceding claims wherein the electrical cable comprises a central core and the metallic conductor comprises a layer of individual metallic wires twisted around such central core, the second marking being provided on at least two adjacent individual wires of the metallic conductor, along a longitudinal axis of the electrical cable.

7. Electrical cable according claim 6 wherein the second marking is applied on an external layer of the metallic conductor or on an internal layer of the metallic conductor or even on the central wire.

8. Electrical cable according claim 5 or 6 wherein the second marking is applied over an insulation of the metallic conductors and the first marking is applied over the external covering of cable.

9. Electrical cable according to claim 6 or 7 wherein each of the first and second markings comprise at least two distinct characters, each character being at least defined by a height (Hl, H2) and a width (I), such height and width being superior to individual wires diameter (d), and inferior to the metallic conductor diameter (D) and inferior to the electric cable diameter (De).

10. Electrical cable according to claim 9 wherein character height and width are at least 25% of individual wires diameter (d), and less than 50% of the metallic conductor diameter (D).

11. Electrical cable according to any of claims 6 to 10 wherein the layer of individual wires defines an outer surface, an inner surface of the external covering being adjacent to such outer surface of the layer of individual wires.

12. Electrical cable according to the preceding claims wherein several first markings are performed all along the external covering at a substantially constant first interval, the second marking being repeated on an outer surface of the metallic conductor at a substantially constant second interval, the constant first interval being derived from the constant second interval.

13. Electrical cable according to one of the preceding claims wherein the first and second marking are either inkjet, laser printed or other engraving methods such as high or low relief engraving.

14. Electrical cable according to one of the preceding claims wherein the metallic conductor is flexible or rigid, the metallic conductor comprises copper, aluminum or mixture thereof, and the metallic conductor being circular or noncircular in cross section.

15. Electrical cable according to one of the preceding claims wherein the metallic conductor is tinned, silver-plated or nickel-plated copper or aluminiumconductor.

16. Electrical cable according to one of the preceding claims wherein the metallic conductor is consisting of a single wire.

17. Electrical cable according to one of preceding claims wherein it is constructed for low voltage, medium voltage or high voltage applications.

18. Electrical cable according to one of the preceding claims wherein it is waterproof, and comprises water blocking means to avoid water penetration.

19. Reeled cable comprising a support and an electrical cable according to any previous claims, the electrical cable being reeled in successive layers around the support.

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