AU2012244327A1

AU2012244327A1 - Wrapper for encapsulating a cable connection area as well as a cable assembly and node comprising same

Info

Publication number: AU2012244327A1
Application number: AU2012244327A
Authority: AU
Inventors: Piotr Gorecki; Ghislain Mendes
Original assignee: Societe Industrielle de Construction dAppareils et de Materiel Electriques SICAME SAS
Current assignee: Societe Industrielle de Construction dAppareils et de Materiel Electriques SICAME SAS
Priority date: 2011-11-07
Filing date: 2012-11-05
Publication date: 2013-05-23
Anticipated expiration: 2032-11-05
Also published as: EP2590286A1; AR088679A1; FR2982434A1; MX2012012985A; FR2982434B1; AU2012244327B2

Abstract

TITLE OF THE INVENTION Wrapper for encapsulating a cable connection area as well as a cable assembly and node comprising same TEXT OF THE The wrapper is configured to make it possible to inject a polymerizable liquid resin precursor between the cable connection area and the wrapper. It is formed by a jacket (11) comprising a skin (18) made from a flexible material that is impervious to liquids and a slide fastener (29) for securing two opposite longitudinal edges of said skin (18). The assembly comprises the jacket (11) and two seals (12), each configured to receive at least one cable (2, 3). The node comprises the connection area and the assembly placed over this area. (Figure 8) cc oo CC CO' Co

Description

1 5 The invention relates to the encapsulation of the areas for the connection of cables forming part of an underground network for the distribution of electrical power for example. It is known that in order to connect cables, it is necessary to remove a certain length of the outer sheath of each cable as well as the shielding metal 10 screen surrounding the conductor(s) if the cables comprise such a screen; and in order to give the area where the cables are connected a similar level of protection to that provided by the outer sheath of the cables, it is known to encapsulate the connection area with a resin obtained by means of a liquid resin precursor injected between the cable connection area and a wrapper 15 formed for this purpose around the cable connection area, said resin precursor hardening by polymerization to become a resin which then encapsulates the cable connection area. Conventionally, the wrapper is formed by adhesive tape placed around a foam spacer layer that is pervious to liquids, the wrapper being 20 generally equipped with an injection nozzle and one or more air evacuation vent(s). European patent application EP 1 505 693 proposes a wrapper formed by a strip of material two longitudinal edges of which comprise adhesive retaining means to allow the strip of material to be held around the connection 25 area. The invention aims to provide a wrapper that is simpler and more convenient to use. A wrapper is proposed to this end for encapsulating a cable connection area, configured to allow the injection of a polymerizable liquid resin 30 precursor between the cable connection area and the wrapper, to give a resin encapsulating said cable connection area, characterized in that said wrapper is formed by a wrapping jacket comprising a skin that is made from a flexible 2 material that is impervious to liquids and a fastener with a slider to secure two opposite longitudinal edges of said skin, said jacket being configured to form, in a closed condition in which said two longitudinal edges are secured to each other by said fastener, a sleeve that is impervious to liquids laterally 5 surrounding said cable connection area. Thanks to the slide fastener, installing the jacket according to the invention is particularly convenient, since in order to secure the two longitudinal edges to each other, it is only necessary to move the slider of the fastener.+ Furthermore, a slide fastener offers the advantage of providing a 10 fastening that is particularly reliable in environments such as sites where underground electrical power distribution networks are installed or maintained. Even if there is a little dust or soil on the slide fastener, once the slider has closed, the two longitudinal edges will remain reliably secured to each other, unlike the adhesive joint proposed in European patent application EP 15 1 505 693 (the soil or dust will prevent the adhesive of one of the longitudinal edges bonding with the other longitudinal edge). According to preferred characteristics, said fastener with a slider comprises two tapes, each fixed along a respective one of said opposite longitudinal edges and each comprising a respective initial portion beyond a first 20 transverse edge. The initial portions allow the slider to build up a little speed before being situated along the longitudinal edges of the skin, making it possible for example to facilitate installation when the skin must be stretched over the cable connection area. 25 According to preferred characteristics, said tapes each comprise, beyond a second transverse edge, a respective final portion. The final portions allow the slider to be placed beyond the longitudinal edges of the skin and therefore to be certain that the two longitudinal edges are firmly secured to each other over their entire length. 30 According to other preferred characteristics, for reasons of simplicity and convenience of use: - said skin comprises two protrusions; and/or 3 - said jacket comprises a nozzle for injection of said resin precursor and at least one air evacuation vent. In a second aspect, the invention also relates to an assembly for encapsulating a cable connection area, comprising a jacket as disclosed above 5 and two seals configured to each receive at least one cable and to be surrounded by said jacket along a respective transverse edge. In a third aspect, the invention also relates to a cable node comprising: - a cable connection area comprising a connector, at least one first 10 cable extending from a first side of the connector and at least one second cable extending from a second side of the connector opposite said first side, with each said first cable and second cable comprising an outer sheath surrounding at least one conductor having a core of conductive material and an individual sheath covering the conductive core, said outer sheath of the first cable being 15 removed between the connector and an area where the first cable is uncut, said outer sheath of the second cable being removed between the connector and an area where the second cable is uncut, the conductor of the first cable being engaged in said connector, the conductor of the second cable being engaged in said connector; and 20 - an assembly as disclosed above, with each said seal being installed respectively over said area where the first cable is uncut and over said area where the second cable is uncut. The invention will now be further disclosed via a detailed description of embodiments of the invention given illustratively and non-limitatively 25 hereinafter with reference to the attached drawings, in which: - Figure 1 is a perspective view of a cable connection area equipped with end seals of an encapsulation assembly according to the invention; - Figures 2 to 4 are views similar to Figure 1 showing successive 30 steps of equipping the cable connection area with a first spacer layer, a conductive layer and a second spacer layer of the assembly to be encapsulated respectively; 4 - Figure 5 is a plan view of a jacket of the assembly to be encapsulated, intended to wrap the cable connection area equipped as shown in Figure 4; - Figure 6 is a detail of a terminal end of one tape of the slide 5 fastener that the jacket comprises; - Figure 7 is a perspective view showing the jacket partially installed on the cable connection area equipped as shown in Figure 4; - Figure 8 is a view similar to Figure 7 but with the jacket installed over the equipped connection area, in the closed condition; and 10 - Figure 9 is a view similar to Figure 1 for a variant of the cable connection area. Figure 1 shows a cable connection area 1 comprising a main cable 2, two branch cables 3 and a connector 8 by means of which cables 2 and 3 are connected in parallel. 15 The main cable 2 comprises four conductors, respectively three phase conductors 46 (only two of which are shown on the drawings) and a neutral conductor 47. Similarly, each branch cable 3 comprises three phase conductors 48 and a neutral conductor 49. The conductors 46 to 49 each comprise a metal conductive core 20 covered with an insulating plastic sheath or, for the neutral conductors, a lead sheath. In the cable 2, the four conductors 46 and 47 are surrounded firstly by a shielding metal screen and then by an outer insulating plastic sheath; the same applies to the four conductors 48 and 49 of each cable 3. The cross-section of the conductors 46 and 47 of the main cable 2 is 25 greater than the cross-section of the conductors 48 and 49 of each branch cable 3. The outside diameter of the cable 2 is greater than the outside diameter of the cables 3. As shown in Figure 1, the conductors 46 and 47 of the cable 2 are each connected to a respective conductor 48 or 49 of each cable 3 by the 30 connector 8. Moreover, the neutral conductors 47 and 49 are connected to a metal earthing braid 17.

5 Here, the main cable 2 and the branch cables 3 each extend on either side of the connector 8. The connector 8 is a four-phase insulation piercing connector, providing the electrical connection between the pairs of conductors to be connected. 5 Here, the four-phase connector 8 is as described in French patent application 2 901 413. Here, the cable connection area 1 forms part of an underground network for the distribution of three-phase low-voltage electrical power. In order to connect the conductors of the cables 2 and 3 with the 10 connector 8, it has been necessary to remove a certain length of the shielding metal screen and the outer sheath of each cable 2 and 3. Described hereinafter is an assembly 10 (Figures 7 and 8) for encapsulating the connection area 1, in order to provide to the connector 8 and to the conductors of the cables 2 and 3 similar protection to that provided by the 15 shielding metal screen and by the outer sheath. The assembly 10 comprises two identical seals 12 and 13, a first spacer layer 14 (Figure 2), a conductive layer 15 (Figure 3), a second spacer layer 16 (Figure 4) and a jacket 11 (Figures 5 to 8). Once the different elements of the assembly 10 are in place over the 20 connection area 1, a polymerizable (curable) liquid resin precursor is injected between the cable connection area 1 and the jacket 11. When the resin precursor has polymerized (cured), it gives a resin encapsulating the cable connection area 1. The seals 12 and 13 are made from flexible foam and are impervious 25 to liquids (closed-cell). The seals 12 and 13 are cylindrical. Here, each has two through-holes 50 and 51 as well as through-slots 52 and 55. The hole 50 has a diameter corresponding to that of the main cable 2 and the hole 51 has a diameter corresponding to that of the branch cable 3. The slot 52 extends from the hole 50 to the outer edge of the seal 12 30 or 13.

6 The slot 55 is spaced apart from the holes 50 and 51 and the edge of the seal 12 or 13. The length of the slot 55 corresponds to the width of the braid 17. In Figure 1, the connection area 1 is equipped with the seals 12 and 5 13. Seal 12 is placed at a first end of the connection area 1, in an area where both cables 2 and 3 are uncut. The seal 13 is placed at a second end of the connection area 1 opposite to the first end in an area where both cables 2 and 3 are uncut. At each seal 12 or 13, the cable 2 is housed in a hole 50 and the cable 3 in a hole 51. The slot 52 allows the seal 12 or 13 to be installed on the 10 cable 2. The cables 3 are each threaded into the hole 51 respectively in the seal 12 and in the seal 13. The slot 55 in the seal 13 receives the metal earthing braid 17 of the neutral pole. Installation is carried out by threading the braid 17 through the slot 55. 15 The first spacer layer 14 (Figure 2) is made from flexible foam and is pervious to liquids (open-cell). The width of the layer 14 corresponds to the width of the connector 8. In a variant, the width of the layer 14 is greater than the width of the connector 8. 20 The length of the layer 14 corresponds to the perimeter of the connector 8. The thickness of the layer 14 corresponds to a gap that must be ensured between the circumference of the connector 8 and a screen made from conductive material in this case formed by the conductive layer 15 (Figure 3). In Figure 2, the connection area 1 is equipped with the layer 14, 25 which directly surrounds the connector 8. In order to allow the first layer 14 to remain around the connector 8, the two ends of the layer 14 that meet are held together by a piece of adhesive tape. In a variant (not shown), one of the ends comprises a tab, the other end has a slot and the tab is passed through the slot to hold the two ends together. 30 Here, the conductive layer 15 (Figure 3) is a metal mesh that is pervious to liquids.

7 The width of the conductive layer 15 corresponds to the sum of the width of the connector 8 and twice the distance over which the shielding screen and the outer sheath of the cables 2 and 3 is removed. The distance between the seals 12 and 13 is greater than the width of the conductive layer 15 so that 5 between each seal 12 and 13 and the corresponding transverse edge of the layer 15, there is a certain distance over which the cables 2 and 3 are uncut. The length of the conductive layer 15 is sufficient for it to be able to completely surround the connection area 1. The conductive layer 15 is held over the connection area 1 by means 10 of for example an adhesive tape surrounding it close to the seal 12 and the seal 13. The conductive layer 15 is in contact with the metal braid 17. As a result, there is an electrical connection between the conductive layer 15 and the metal braid 17, so that if the braid 17 is earthed, the conductive layer 15 is 15 thereby also earthed. The second spacer layer 16 is made from the same material as the layer 14, i.e. a flexible foam that is pervious to liquids (open-cell). The spacer layer 16 has a width corresponding to the gap between the seals 12 and 13 and a length allowing it to completely surround the metal 20 layer 15. In order to allow the second layer 16 to be held around the conductive layer 15, the two ends of the layer 16 that meet are held together by a piece of adhesive tape. In a variant (not shown), one of the ends of the layer 16 comprises a plurality of tabs, the other end has a plurality of corresponding 25 slots, and the different tabs are passed through the corresponding slots to hold the two ends together. The jacket 11, as shown in Figures 5, 7 and 8, comprises a skin 18, a slide fastener 19, a nozzle 31 and three vents 32. The skin 18 extends longitudinally from a first transverse edge 35 to 30 a second transverse edge 36. It comprises two opposite longitudinal edges 20 and 21.

8 The skin 18 is made from flexible material that is impervious to liquids, having a constant overall thickness, shaped like a sheet with two protrusions 33 and 34, each midway of the transverse edges 35 and 36. The protrusion 33 is close to the edge 21. The protrusion 34 is 5 contiguous with the protrusion 33 and at a distance from the edge 20. Between the protrusion 34 and the longitudinal edge 20, the nozzle 31 and the vents 32 are arranged in a substantially aligned manner. The nozzle 31 and the vents 32 protrude from the skin 18 on the side where the protrusions 33 and 34 are convex. 10 The nozzle 31 delimits an injection pipe 37 opening respectively at the apex of the nozzle 31 and through the skin 18. Each vent 32 delimits an air evacuation pipe opening via an orifice 38 in a cap situated at the apex of the vent 32 and through the skin 18. Here, the skin 18, the nozzle 31 and the vents 32 are moulded from a 15 single piece made from the same material. The length of the jacket 11 (distance between the transverse edges 35 and 36) corresponds to the sum of the distance between the seals 12 and 13 and the thickness of the seals. As the seals 12 and 13 are each installed in an area where the 20 cables 2 and 3 are uncut, the width of the jacket 11 is greater than the sum of the width of the connector 8, twice the distance over which the shielding screen and the outer sheath of cables 2 and 3 is removed, the thickness of the seal 12 and the thickness of the seal 13. In practice, the width of the jacket 11 is designed so that the edge 35 25 is level with the outer face of the seal 12 (facing away from the connector 8) and the edge 36 is level with the outer face of the seal 13 (facing away from the connector 8). The width of the jacket 11 (distance between the edges 20 and 21) is such that when the equipped connection area 1 as shown in Figure 4 is 30 surrounded by the jacket 11, by placing the edge 20 level with the edge 21, the skin 18 is slightly stretched.

9 Here, the material of the skin 18 is rubber, which has a slight elasticity. The slide fastener 19 comprises two tapes 22 and 23 and a slider 29. Here, the fastener 19 is of the type commonly found on clothing. 5 The tapes 22 and 23 are the same length. They are each fixed, in this case by stitching, along a respective longitudinal edge 20 and 21. The tapes 22 and 23 are longer than the distance between the edge 35 and the edge 36 of the skin 18. They each extend from a respective initial portion 24 and 25 beyond the edge 35 to a respective final portion 26 and 27 beyond the 10 edge 36. Each tape 22 and 23 comprises a stop 30, a tab 41 and a series of teeth 28 (see Figure 6). The tab 41 is situated at the distal end of the respective initial portion 24 and 25. The tab 41 of the tape 23 prevents the slider 29 from leaving the 15 tape 23 at the end of the portion 25. The tab 41 of the tape 22 is configured to be inserted into a groove of the slider 29 and thus allow the sliding engagement of the slider 29 on the tape 22. The stop 30 (shown in Figure 6) is situated at the end of the respective final portion 26 and 27. This stop 30 prevents the slider 29 from 20 leaving the tapes 22 and 23 at the end of its sliding travel. On each tape 22 and 23, the series of teeth 28 extends between the tab 41 and the stop 30. The slide fastener 19 is provided to secure the tapes 22 and 23 together by moving the slider 29 between the tabs 41 and the stops 30. 25 Except in the extreme positions shown in Figures 5 and 8, i.e. when the slider 29 is in an intermediate position between the tabs 41 and the stops 30, between the tabs 41 and the slider 29, the teeth 28 of the tapes 22 and 23 are mutually engaged with each other, while between the slider 29 and the stops 30, the teeth 28 of the tape 22 are free with respect to the teeth 28 of the 30 tape 23. In order to pass from the open position of the jacket 11 shown in Figures 5 and 7 to the closed position shown in Figure 8, the jacket 11 is curved 10 so that the slider 29 is opposite the tab 41 of the tape 22, the tab 41 is engaged in the slider 29 and the slider 29 is slid along the tapes 22 and 23 until it reaches the stops 30. In the closed condition (Figure 8), the slide fastener 19 is impervious 5 to liquids. In order to place the jacket 11 over the equipped connection area 1 as shown in Figure 4, the edges 35 and 36 are placed level with the outer faces respectively of the seal 12 and the seal 13 with the protrusion 34 as well as the nozzle 31 and the vents 32 above the connection area 1 and the elements with 10 which it is equipped, with the protrusion 34 centred on the connector 8. The position shown in Figure 7 has then been reached. The connection area thus equipped with the jacket 11 is then surrounded by passing the tape 23 under the connection area 1 so that it adopts a position facing the tape 22 in order to allow the tab 41 of the tape 22 to 15 be engaged in the slider 29. The slider 29 is then slid until it reaches the stops 30. The jacket 11 is then in the closed condition shown in Figure 8, where it forms a sleeve that is impervious to liquids, laterally surrounding the connection area 1. 20 When the slider 29 is slid from the tabs 41 to the stops 30, the initial portions 24 and 25 come closer together while the skin 18 is stretched and the seal 12 is compressed; when the slider is beyond the initial portions 24, the skin 18 is stretched around the equipped connection area 1, the seal 13 is compressed and the slider 29 passes beyond the skin 18 and arrives at a 25 position in contact with the stops 30 in the final portions 26 and 27. The relatively important length of the initial portions 24 and 25 allows the slider 29 to build up a little speed to pass the seal 12 and to achieve a degree of progressive tensioning of the skin 18. The length of the final portions 26 and 27 allows the slider 29 to be 30 accommodated beyond the skin 18. It will be noted that the protrusions 33 and 34 are shaped so that the jacket 11 fits closely around the connector 8.

11 Due to the fact that the jacket 11 closely surrounds the seals 12 and 13, compressing them, and the fact that the slide fastener 19 is impervious to liquids, the jacket 11 and the seals 12 and 13 form an enclosure, impervious to liquids, around the connection area 1. 5 When the assembly to be encapsulated is in place as shown in Figure 8, it is then possible to inject the liquid resin precursor via the pipe 37. The resin precursor then fills the space delimited by the connection area 1, the seals 12 and 13 and the jacket 11. The air initially contained in this space is evacuated via the orifices 10 38 of the vents 32. The resin precursor polymerizes (cures) and gives a resin encapsulating the cable connection area 1. The first spacer layer 14 makes it possible to ensure that there is a predetermined thickness of resin between the connector 8 and the conductive 15 layer 15. Similarly, the second spacer layer 16 makes it possible to ensure that there is a predetermined thickness of resin around the conductive layer 15. The connection area 1, the assembly 10 and the encapsulation resin then form a cable node capable of being buried together with the cables 2 and 3. 20 Figure 9 shows a variant of the cable connection area 1 described above. In this variant, there is only one branch cable 3, extending from the side of the cable connection area 1 equipped with the seal 13. The conductors 47 and 48 are thus engaged in the connector 8 by a respective end. In this variant, the scored cutout 54 produced during the 25 manufacturing of the seal 12 has been left in place in the hole 51 in order to ensure imperviousness to liquids. In variants (not shown), the cable connection area comprises a connector and cables arranged differently, for example two main cables connected end-to-end; and/or the cables form part of a single-phase network. 30 In other variants (not shown), where the cables have no shielding screen, the conductive layer such as 15 and the spacer layer such as 16 are dispensed with.

12 In variants (not shown), the jacket is used differently, for example without the seals 12 and 13, with the seal at the ends of the jacket achieved by adhesive tape. In the example shown, the skin 18, the nozzle 31 and the vents 32 of 5 the jacket 11 are moulded from a single piece in standard fashion, i.e. between two rigid moulds. In a variant, the nozzle such as 31 and the vents such as 32 are produced by overmoulded inserts; blow-moulding is used; and/or the number of vents such as 32 is different from three, for example two or four. In variants (not shown), the slide fastener such as the fastener 19 is 10 different, with for example the final portions such as 26 and 27 being dispensed with; and/or the series of teeth 28 are replaced respectively by a longitudinal rib and by a longitudinal groove with the slider such as 29 being configured to make the rib engage in the groove. Many other variants are possible depending on the circumstances, 15 and it is noted in this respect that the invention is not limited to the examples described and shown.

Claims

1. A wrapping for encapsulating a cable connection area (1), configured to allow the injection of a polymerizable liquid resin precursor between the cable connection area (1) and the wrapping, to give a resin 5 encapsulating said cable connection area, characterized in that said wrapping is formed by a wrapping jacket (11) comprising a skin (18) made from a flexible material that is impervious to liquids and a fastener (19) with a slider (29) to secure two opposite longitudinal edges (20, 21) of said skin (18), said jacket (11) being configured to form, in a closed condition in which said two 10 longitudinal edges (20, 21) are secured to each other by said fastener (19), a sleeve that is impervious to liquids, laterally surrounding said cable connection area.

2. Wrapper according to claim 1, characterized in that said fastener (19) with a slider (29) comprises two tapes (22, 23) each fixed along a 15 respective one of said opposite longitudinal edges (20, 21) and each comprising beyond a first transverse edge (35), a respective initial portion (24, 25).

3. Wrapper according to claim 2, characterized in that said tapes (22, 23) each comprise beyond a second transverse edge (36), a respective final portion (26, 27). 20

4. Wrapper according to any one of claims 1 to 3, characterized in that said skin (18) comprises two protrusions (33, 34).

5. Wrapper according to any one of claims 1 to 4, characterized in that said jacket comprises a nozzle (31) for injection of said resin precursor and at least one air evacuation vent (32). 25

6. Assembly for encapsulating a cable connection area (1), comprising a jacket (11) according to any one of claims 1 to 5 and two seals (12, 13) configured to each receive at least one cable (2, 3) and to be surrounded by said jacket along a respective transverse edge (35, 36).

7. Assembly according to claim 6, characterized in that it also 30 comprises at least one spacer layer (14, 16).

8. Cable node comprising: 14 - a cable connection area (1) comprising a connector (8), at least one first cable (2) extending from a first side of the connector (8) and at least one second cable (3) extending from a second side of the connector (8) opposite said first side, with each said first cable (2) and second cable (3) comprising an 5 outer sheath surrounding at least one conductor (46-49) having a core of conductive material and an individual sheath covering the conductive core, said outer sheath of the first cable (2) being removed between the connector (8) and an area where the first cable (2) is uncut, said outer sheath of the second cable (3) being removed between the connector (8) and an area where the second 10 cable (3) is uncut, the conductor (46, 47) of the first cable (2) being engaged in said connector (8), the conductor (48, 49) of the second cable (3) being engaged in said connector (8); and - an assembly according to any one of claims 6 or 7, with each said seal (12, 13) installed respectively over said area where the first cable (2) is 15 uncut and over said area where the second cable (3) is uncut.

9. Node according to claim 8, characterized in that said jacket (11) is placed around said cable connection area (1) from one of said seals (12) to the other one of said seals (13).

10. Node according to claim 9, characterized in that said jacket (11) 20 is configured to fit tightly around said cable connection area (1), compressing each of said seals (12, 13).