JP4574276B2 - Waterproof structure for cable connection and method for forming the sealed structure - Google Patents

Description

The present invention mainly provides a water shielding structure for a cable connecting portion in which a cylindrical water shielding body such as a water shielding tube or a water shielding tube having water shielding properties is provided in a cable connecting portion that connects power cables to each other or is constructed on a power cable terminal. The present invention also relates to a method for forming the water shielding structure .

  In general, a power cable is required to have high water shielding performance at the cable connection portion of the power cable together with the power cable body in order to stabilize the electrical performance and stabilize the power supply.

  Various types of water-blocking structures are employed to increase the water-blocking performance of this type of cable connection.

  One of them is a water shielding structure that covers a cable connecting portion with a water shielding structure made of an assembled metal pipe.

  Another one is a heat-shrinkable water-insulating tube comprising a waterproof protective layer made of an elastomer such as rubber or plastic, and a water-impervious layer in which a metal layer is wound in a cylindrical shape in the protective layer, It is a water-blocking structure that covers the cable connection.

  Further, another one is a water-blocking structure in which a cable connection portion is covered with a cold-shrinkable water-blocking tube whose diameter is expanded by inserting a core (for example, Patent Document 1, Patent Document 2, Patent Document 3, or , See Patent Document 4).

As disclosed in Patent Documents 1 to 4, this type of cold-shrinkable water-impervious tube is elastically stretched and expanded on a cylindrical core of a hollow support body that can be disassembled and removed. A wound cold-shrinkable rubber elastic layer is provided, and a water-impervious layer in which a metal foil or a metal laminate is wound in a circumferential shape is provided on the upper layer of the cold-shrinkable rubber elastic layer. A cold-shrinkable rubber elastic body layer is provided which covers the outer peripheral surface of the rubber and is wound in an elastically stretched / expanded state.
JP 2000-263690 A JP 2001-231123 A JP 2001-231150 A JP 2002-15790 A

However, the above-described water-impervious structure using a metal tube is inevitably heavy because it is made of metal, and tends to be poor in handling at work.
Especially when connecting power cables installed in underground cable conduits in manholes, or when the water shielding structure that covers the outer periphery of the entire Y branch connection of the power cable is large and heavy. Due to the inferior nature, it took a long time to work and became an obstacle to reducing the work cost.

  In addition, when connecting the connection ends of the power cables as described above, the cold-shrinkable water shielding tube is positioned on the cable connection portion and the core is removed, thereby closely contacting the cable connection portion. Shrink to state. At this time, the water shielding layer is folded or wrinkled by the contraction force of the elastic layer. If the water shielding layer is made of a metal foil or a metal laminate and its mechanical bending performance is low, pinholes may occur due to bending fatigue, and the original water shielding performance may not be exhibited.

  Further, the water shielding layer has irregularities, i.e., peaks and valleys, and the peaks become protrusions, which may push the elastic layer and damage the cold-shrinkable tube.

  The above problems also exist in heat-shrinkable water shielding tubes.

  As described above, a technique for solving the problems caused by using a metal material for the water shielding structure of the cable connection portion has not been proposed.

The present invention has been made in view of such circumstances, and improves the assembling workability of the water shielding structure of the cable connecting portion, and prevents the water shielding performance from deteriorating without causing scratches. It is an object of the present invention to provide a water shielding structure for a part and a method for forming the water shielding structure .

  The present invention relates to a water shielding structure for a power cable connecting portion.

The present invention peels off the internal semiconductive layer from the external protective layer at the connection end of the power cable formed by the conductor, the internal semiconductive layer, the insulating layer, the external semiconductive layer, the shielding layer, and the external protective layer. With the conductor exposed, the conductors of both power cables facing each other for connection are connected to each other by a connecting pipe, and the periphery connected by the connecting pipe is covered with a substantially cylindrical insulator. For the cable connection part in which the semiconductive layer is formed on the periphery and the outer periphery, the outer periphery of the cable connection part is covered with a water shielding body, and the cable connection part prevents water from entering the cable connection part from the outside. Structure,
The outer diameter of the cable connection portion is larger than the outer diameter of the power cable,
The water shielding body does not include a metal material provided with a large diameter portion and a small diameter portion respectively corresponding to the outer diameter of the cable connection portion and the outer diameter of the power cable, and is a pair of rigid water shielding resin tubes. A water-impervious resin layer in which a water-impervious resin layer is wound in a cylindrical shape on the outer peripheral surface side of the cable connection portion, and a room-temperature-shrinkable rubber elastic body wound in a state of covering the outer peripheral surface of the water-impervious layer A first water shielding tube made of a shrinkable tube that does not contain a metal material comprising a layer,
Before connecting the conductors of the two power cables with a connecting pipe, the first water shielding tube is wound in a state where the water shielding layer is brought into contact with a removable cylindrical core and elastically expanded in diameter. And then send it to a position away from the connection end of the power cable on one side, and then cover the power cable on both the one side and the other side with a water shielding pipe respectively.
After forming the cable connection portion by connecting the two power cable conductors with a connecting pipe,
By a pair of impermeable tube in the water-impervious material, said cable connection part respectively over the connection end portion outer peripheral surface on both power cables made to face from the longitudinal center of the outer peripheral surface was covered in close contact with the first shielding water tubes, said cable connection portion is located near the center of the removal of the core, is a water-impervious structure of a cable connecting portion, characterized in that it has a structure to cover the pair of water-impervious pipe above.

In the present invention, it is preferable that the water shielding body has a pair of second water shielding tubes that closely cover and cover both connection ends of the power cable from the pair of water shielding pipes .

The present invention peels off the internal semiconductive layer from the external protective layer at the connection end of the power cable formed by the conductor, the internal semiconductive layer, the insulating layer, the external semiconductive layer, the shielding layer, and the external protective layer. With the conductor exposed, the conductors of both power cables facing each other for connection are connected to each other by a connecting pipe, and the periphery connected by the connecting pipe is covered with a substantially cylindrical insulator. For the cable connection part in which the semiconductive layer is formed on the periphery and the outer periphery, the outer periphery of the cable connection part is covered with a water shielding body, and the cable connection part prevents water from entering the cable connection part from the outside. A method of forming a structure,
The outer diameter of the cable connection portion is larger than the outer diameter of the power cable,
As a water shielding body, a pair of water shielding pipes made of a rigid water shielding resin pipe not including a metal material provided with a large diameter portion and a small diameter portion corresponding to the outer diameter of the cable connection portion and the outer diameter of the power cable, respectively. A water-impervious resin layer in which a water-impervious resin layer is wound in a cylindrical shape on the outer peripheral surface side of the cable connection portion, and a room-temperature-shrinkable rubber elastic body wound in a state of covering the outer peripheral surface of the water-impervious layer A first water shielding tube made of a shrinkable tube that does not contain a metal material made of a layer,
Before connecting the conductors of the two power cables with a connecting pipe, the first water shielding tube is wound in a state where the water shielding layer is brought into contact with a removable cylindrical core and elastically expanded in diameter. A first step of feeding the product to a position away from the connection end of the power cable on one side;
A second step in which both the power cables on one side and the other side are respectively covered with a water shielding pipe and sent to a position away from the connection end;
A third step of connecting the power cable conductors to each other by a connecting pipe to form the cable connecting portion;
A fourth step of closely covering each of the connecting end portions of the power cables facing each other from the outer peripheral surface portion in the longitudinal direction of the cable connecting portion by a pair of water shielding pipes in the water shielding body; ,
A fifth step of positioning the first water shielding tube in the vicinity of the center of the cable connecting portion to remove the core and covering the pair of water shielding tubes. This is a method of forming a water structure .

  In the present invention, the water shielding resin is preferably made of high density, medium density, or low density polyethylene.

  According to the water shielding structure of the cable connecting portion of the present invention, the assembling workability of the water shielding structure of the connecting portion is improved, and the excellent effect that the water shielding performance can be prevented from being lowered without causing scratches. Can play.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 show a first embodiment which is an example of a mode for carrying out the present invention (hereinafter referred to as “embodiment”). In the drawings, the same reference numerals denote the same parts.

  FIG. 1 is a cross-sectional view taken along the axial direction of the power cable and the connecting portion for schematically explaining the water shielding structure of the cable connecting portion according to the first embodiment, and FIG. 2 is a cross-sectional view taken along the axial direction of the water shield shown in FIG. FIG. 3 is a detailed cross-sectional view along the axial direction of the specific power cable and connecting portion of FIG. 1, and FIG. 4 is a construction explanatory view of a water-blocking structure of the cable connecting portion.

  As shown in FIG. 1, in this embodiment, the cable connection portion that covers the outer periphery of the connection portion (cable connection portion 6) of the power cable with a water shielding body and prevents the water from entering the cable connection portion 6 from the outside. In the water-blocking structure 6, the water-blocking body is a water-blocking structure of the cable connection portion 6 made of resin without including a metal material.

  The water shielding body includes a water shielding layer 22 in which a water shielding resin layer is wound in a cylindrical shape in the circumferential direction on the outer peripheral surface side of the cable connecting portion 6, and a shrinkable rubber wound in a state of covering the outer peripheral surface of the water shielding layer. This is a shrinkable tube comprising an elastic layer 23.

  In addition, the water-impervious body is made of a rigid water-impervious resin tube that covers the outer periphery of the connecting portion. Further, the water shielding resin is made of high density, medium density or low density polyethylene.

  This will be described in more detail.

  In the first embodiment, the water shielding bodies are first and second water shielding tubes 10, 20 </ b> A, and 20 </ b> A that are room temperature shrinkable water shielding tubes as shown in FIG. 2. Specifically, the water-impervious layers 22 of the first and second water-impervious tubes 10, 20 </ b> A, 20 </ b> A are elastically extended and expanded on the cylindrical core 11 of the hollow support body that can be disassembled and removed. The water-blocking resin layer that is wound in such a state and is in contact with the outer peripheral surface of the cable connecting portion 6 is wound in a cylindrical shape in the circumferential direction. The shrinkable rubber elastic body layer 23 is made of a normal temperature shrinkable rubber wound in a state of covering the outer peripheral surface of the water shielding layer 22.

  In addition, the water shielding body is provided with water shielding pipes 20B and 20B in which a water shielding resin layer body or a film body for contacting the outer peripheral surface of the cable connection portion 6 is wound in a cylindrical shape in the circumferential direction.

  Moreover, the installation to the cable connection part 6 of the said water shield is constructed so that it may cover in multiple places on the outer peripheral surface of the cable connection part 6, as shown in FIG. Specifically, the water shielding body includes a pair of water shielding pipes 20 </ b> B covering the two ends of the cable connection portion 6 from both the end portions and the connection ends 5 and 5 of the power cables 4 and 4. 20B (water-blocking body), a first water-blocking tube (water-blocking body) 10 located on the outer periphery near the center of the cable connecting portion 6 and covering the pair of water-blocking tubes 20B and 20B in close contact with each other; A pair of second water shielding tubes 20A, 20A (water shielding bodies) covering the connection ends 5, 5 of the power cables 4, 4 from the pair of water shielding tubes 20B, 20B in close contact with each other. Yes.

  In the embodiment, the water shielding layer 22 of the first water shielding tube 10 and the second water shielding tubes 20A, 20A is in the form of a thin film or sheet made of a water shielding resin such as plastic. The water shielding pipe 20B has a relatively rigid structure made of a water shielding resin such as plastic as a whole.

  As the material of the water-blocking resin (used for the water-blocking layer 22 and the water-blocking pipe 20B), it is preferable to use a polyethylene resin in view of its moisture resistance, water vapor blocking performance, and the like. Among these polyethylenes (: a thermoplastic resin obtained by polymerizing ethylene, the density and characteristics vary depending on the degree of branching, the type of branching, and the distribution), high density polyethylene (HDPE: generally has a density of 0.941 based on the density). ˜0.965 polyethylene) is most preferable, but medium density polyethylene (MDPE: polyethylene having a density of 0.926 to 0.940), low density polyethylene (LDPE: density of 0.910 to 0.96). 925 polyethylene) and ultra-low density polyethylene (ULDPE: polyethylene having a density of 0.885 to 0.909) are preferably used.

  In the embodiment, the elastic body layer 23 is made of an elastic rubber material having elasticity made of ethylene propylene rubber (abbreviated as EPR or EPM) which is a copolymerized pair of ethylene and propylene. In the present invention, it is also preferable to use silicone rubber for the elastic layer. When the first water shielding tube 10 and the second water shielding tubes 20A, 20A are provided on the cable connecting portion 6 and covered by the elastic force of the elastic body layer 23, the water shielding tubes 10, 20A, 20A are tightly connected. It is possible to closely adhere to the cable connection portion 6.

  In the embodiment, a fixing layer 25 is provided between the water shielding layer 22 and the elastic body layer 23 so as to be fixed by adhesion or adhesion so that they are not peeled off. In the case where the fixing layer 25 is bonded using an adhesive, it is preferable to use an adhesive made of a resin such as synthetic rubber, epoxy resin, silicone, or acrylic. Moreover, when the adhering layer 25 adheres using an adhesive, it is preferable to use unvulcanized rubber for the adhesive.

  In the first and second water shielding tubes 10, 20 </ b> A, 20 </ b> A, the dismountable core 11 inserted inside the water shielding layer 22 is made of a resin such as plastic or paper and spirally grooved. 11b is formed, and when the lead 11a at the end in the axial direction of the core 11 is pulled, the core 11 is cut off from the spiral groove 11b and separated and disassembled.

  FIG. 3 is a cross-sectional view illustrating in detail a state in which the cable connection portion 6 according to the first embodiment of FIG. 1 is covered with a water shielding body (water shielding tubes 10, 20A, 20A and a water shielding tube 20B). In FIG. 3, the same reference numerals are given to the common parts with FIG. 1.

  The cable connecting portion 6 includes an external protective layer 27, a shielding copper tape (shielding layer) 28, external semiconductive layers 8a and 8a, insulating layers 8 and 8, an internal half of the connection ends 5 and 5 of the power cables 4 and 4. The conductive layers 8b and 8b are peeled off step by step and the conductors 9 and 9 are exposed and connected. In the power cables 4 and 4, the outer protective layer 27 is removed and the shielding copper tape 28 is exposed.

  In the embodiment, as shown in FIG. 4 to be described later, the cable connecting portion 6 is of a room temperature shrinkable property in which the core 61 is inserted in the same manner as the water shield and the core 61 is removed at the time of installation. In addition, it is preferable that the cable connection portion of the present invention is a so-called prefabricated cable connection portion that is divided into a plurality of division surfaces along the axial direction of the power cable. Moreover, in embodiment, although the cable connection part 6 is a linear connection part which connects the connection end parts 5 and 5 of the power cables 4 and 4 linearly, the water shield of this invention is other bent connection parts. It is also preferable to carry out at a connection part branched into a plurality of parts or a cable terminal part.

  An insulating cylinder (reinforcing insulator) 32 made of substantially cylindrical ethylene propylene rubber or silicone rubber is disposed on the entire outer periphery covering the conductors 9, 9, the conductor connecting pipe 12, and the insulating layers 8, 8. .

  A semiconductive layer (internal semiconductive layer) 33 made of ethylene propylene rubber or silicone rubber is formed around the inner peripheral surface portion of the insulating cylinder 32 around the conductors 9 and 9 connected by the conductor connecting pipe 12. .

  In addition, the insulating cylinder 32 is formed with semiconductive layers (external semiconductive layers) 34 and 34 from both ends in the axial direction to the outer peripheral surface. The outer peripheries of the semiconductive layers 34 and 34 and the shielding copper tapes 28 and 28 are wound with semiconductive tape materials 34a and 34a made of carbon table or the like.

  Further, one end of the ground wire 35 is electrically connected to the shielding copper tape 28 exposed from the connection end 5 on one side of the power cables 4 and 4. The grounding wire 35 connected to the shielding copper tape 28 is wound around the outer peripheral surface of the outer semiconductive layer 34 of the insulating cylinder 32 in a spiral shape with an appropriate interval (the wound grounding wire is a “shielding layer” denoted by reference numeral 36). . The other end of the shielding layer 36 wound around the outer peripheral surface of the external semiconductive layer 34 is electrically connected to the shielding copper tape 28 of the connection end portion 5 on the other side of the power cables 4 and 4. In addition, it is preferable that the shielding layer 36 wound around the outer peripheral surface of the external semiconductive layer 34 has a mesh shape.

  Note that a grounding fitting 37 that is electrically connected to the shielding copper tape 28 and connected to the ground (grounded) is provided at the connection end portion 5 on the other side of the power cables 4 and 4.

  With respect to the water shielding tube 20B, the first water shielding tube 10 and the second water shielding tubes 20A and 20A are in close contact with the outer periphery of the semiconductive layer (external semiconductive layer) 34 and the shielding layer 36 of the cable connecting portion 6 described above. To do. The fixing structure of the impermeable tube 20B, the first impermeable tube 10 and the impermeable tubes 20A, 20A in the embodiment is configured such that the impermeable tube 20B is surrounded by the first impermeable tube 10 and the second impermeable tube 20A, 20A is tightened tightly by its own elastic force, and the water shielding tube 20B is sufficiently fixed to the cable connecting portion 6.

  Next, the operation of the first embodiment will be described.

  When connecting the connection ends 5 and 5 of the power cables 4 and 4 with the cable connection 6, first, as shown in FIG. 4, first, the exterior of the connection ends 5 and 5 of the power cables 4 and 4. 7, 7, shielded copper tape (shield layer) 28, 28, outer semiconductive layers 8a, 8a, insulating layers 8, 8, internal semiconductive layers 8b, 8b are peeled off stepwise to expose conductors 9, 9. Let

  Next, the first (cold-shrinkable) water shielding tube 10 whose diameter has been expanded by inserting the cylindrical core 101 that can be dismantled is covered with the power cable 4 on one side (right side in FIG. 4), and the connection end It is sent to the power cable 4 on one side at a position separated from the parts 5 and 5.

  Then, the power cables 4 and 4 on one side and the other side (left side in FIG. 4) are connected to the second (cold-shrinkable) water-proof tubes 20A and 20A and the water-proof tubes 20B and 20B that are slightly flexible and rigid. These are also fed onto the power cables 4 and 4 at positions separated from the connection ends 5 and 5.

  Next, the cable connection portion 6 whose diameter has been expanded by the core 61 that can be disassembled and removed is placed on the power cable 4 on the other side. The cable connection portion 6 has an internal semiconductive layer 33, an insulating cylinder (reinforcing insulator layer) 32, an external semiconductive layer 34, a shielding layer 36, etc., which are appropriately laminated and configured to be elastically deformable. It's sex.

  Then, the connection end portions 5 and 5 are brought close to each other, and the tip portions of the conductors 9 and 9 are compression-connected by the conductor connection tube (sleeve) 12. Thereafter, the cable connection portion 6 is positioned on the connection end portions 5 and 5 and the core 61 that has been expanded in diameter is removed, whereby the cable connection portion 6 is reduced in diameter and the conductor connection tube 12 is removed. In this way, the conductors 9 and 9 that are compression-connected to each other are brought into close contact with each other on the connection end portions 5 and 5 so that electrical performance can be exhibited.

  Next, the water shielding pipes 20 </ b> B and 20 </ b> B are inserted and covered on both ends of the cable connection part 6. Then, the second water shielding tubes 20A and 20A are further covered by covering the water shielding tubes 20B and 20B with the second water shielding tubes 20A and 20A and removing the cores 111 and 111 which have expanded their diameters. The diameter is reduced and overlapped on the water shielding pipes 20B and 20B and the power cables 4 and 4 on both ends of the cable connecting portion 6 and closely adheres to it.

  Then, the water shielding pipes 20B and 20B that are in close contact with the peripheral surfaces of the both ends of the cable connection part 6 are integrally covered with the first water shielding pipe 10 having a large diameter, and the core 101 is removed to remove the core 101. As shown in FIG. 2, the first water shielding tube 10 is reduced in diameter and is in close contact with the second water shielding pipes 20B and 20B on the outer periphery of the cable connecting portion 6.

  When connecting the connection ends of the power cables as described above, the cold-shrinkable water shielding tube whose diameter has been expanded by the core is positioned on the cable connection portion, the core is removed, and the cold-shrinkable shielding tube is removed. The water tube is shrunk by its elastic force and is put in a state of being tightly adhered onto the cable connection portion. Since the water shielding layer is made of a resin, the mechanical bending performance is high, and it is possible to effectively prevent the occurrence of pinholes due to bending fatigue, so that the original water shielding performance can be sufficiently exhibited.

  In addition, even when the water shielding layer is folded or wrinkled by the contraction force of the elastic layer, the water shielding layer has irregularities, that is, peaks and valleys, and the peaks are There is no protrusion, and the elastic layer is not pushed and the cold-shrinkable tube is not damaged at all.

  The water shielding structure for the power cable connecting portion of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the scope of the present invention.

5 to 7 show Reference Example 1 to Reference Example 3 .

In Reference Example 1 shown in FIG. 5, the water shielding body of the present invention is replaced by the first water shielding tube 10, the second water shielding tubes 20 </ b> A and 20 </ b> A, and the water shielding pipe 20 </ b> B according to the first embodiment. The integrated third water shielding tube 40 is used. The third water shielding tube 40 is a cylindrical room temperature shrinkable water shielding tube that collectively covers the connection ends 5 and 5 of the power cables 4 and 4 and the cable connection portion 6, and the structure thereof is illustrated in FIG. This is the same as the first water shielding tube 10 and the second water shielding tubes 20A and 20A shown in FIG.
And in this reference example 1 , since the cable connection part 6 is a thing with few outside diameter differences, such as the same diameter or substantially the same diameter as the electric power cables 4 and 4, the whole is the integral 3rd water-impervious tube 40. The so-called one-piece type water shielding tube is made to cover.

  With the third water shielding tube 40, the water shielding construction of the cable connecting portion 6 can be performed easily and in a short time without using a water shielding tube or a plurality of water shielding tubes as shown in FIG. Although not shown in detail between the cable connecting portion 6 and the third water shielding tube 40, it is preferable to form a semiconductive outer semiconductive layer, a semiconductive tape material 34a, and a shielding layer 36. .

The water shielding body of Reference Example 2 shown in FIG. 6 replaces the first water shielding tube 10, the second water shielding tubes 20 </ b> A, 20 </ b> A, and the water shielding pipe 20 </ b> B according to the first embodiment with the power cables 4, 4. Between the connection end portions 5 and 5 and the both ends of the cable connection portion 6 is covered with the fourth water shielding tube 41, and the two fifth ends over the both ends of the cable connection portion 6 and the fourth water shielding tube 41. The water shielding tube 42 is covered. The fourth and fifth impermeable tubes 41 and 42 are cylindrical cold-shrinkable impermeable tubes that cover appropriate positions between the connecting ends 5 and 5 of the power cables 4 and 4 and the cable connecting portion 6. The structure is the same as the first water shielding tube 10 and the second water shielding tubes 20A and 20A shown in FIG.

In the water shielding body of the reference example 2 , the outer diameter difference between the connection ends 5 and 5 of the power cables 4 and 4 and the cable connection part 6 is larger than that of the first modification. It is a so-called three-piece type that is covered with three impermeable tubes of the impermeable tube 5.
Therefore, in the water shielding body of the reference example 2 , the cable connecting portion having the outer diameter difference is obtained by covering the both ends of the cable connecting portion 6 and the fourth water shielding tube 41 with the two fifth water shielding tubes 42. 6 and the connection ends 5 and 5 of the power cables 4 and 4 can be reliably shielded from water.
Although not shown in detail between the cable connecting portion 6 and the water shielding tube 40, it is preferable to form a semiconductive outer semiconductive layer, a semiconductive tape material 34a, and a shielding layer 36.

Reference Example 3 shown in FIG. 7 replaces the water shielding body of the present invention with the first water shielding tube 10, the second water shielding tubes 20 </ b> A, 20 </ b> A, and the water shielding pipe 20 </ b> B according to the first embodiment. The cylindrical sixth water shielding tube 43 made of an integral water shielding resin and the sixth water shielding tube 43 are covered. The sixth water shielding tube 43 is covered with a waterproof tape or a waterproof tube 44 so that the sixth water shielding tube 43 is fixed on the cable connecting portion 6.

  Unlike the water shielding tube shown in FIG. 2, the sixth water shielding tube 43 is entirely made of a water shielding resin using the above-described high density, medium density or low density polyethylene. In addition, the sixth water shielding tube or waterproof tube 44 is preferably a cylindrical room temperature shrinkable tube as shown in FIG. The waterproof tape 44 is wound around the sixth water shielding tube 43 and applied.

  With the sixth water shielding tube 43, the water shielding construction of the cable connecting portion 6 can be performed easily and in a short time without using a water shielding tube or a plurality of water shielding tubes as shown in FIG. Although not shown in detail between the cable connecting portion 6 and the sixth water shielding tube 43, it is preferable to form a semiconductive external semiconductive layer, a semiconductive tape material 34a, and a shielding layer 36. .

Next, Reference Example 4 of the present invention will be described.

FIG. 8 is a cross-sectional explanatory view of the cable connecting portion 45 according to Reference Example 4 and a water shielding pipe for waterproofing the same.

The present invention covers the outer periphery of the connection portion of the power cable with a water shielding body, and in the water shielding structure of the cable connection portion for preventing the water from entering the cable connection portion from the outside, the water shielding body does not include a metal material. In this Reference Example 4 , the water shielding body has a rigid water shielding resin tube structure covering the outer periphery of the connecting portion.

  Specifically, the water shield is a rigid body made of the above-described high density, medium density or low density polyethylene.

  The cable connection portion 45 shown in FIG. 8 is a Y-branch type connection portion. The connection ends 5 of the three power cables 4 can be connected. In FIG. 8, the connection end portions 5 and 5 of the two power cables 4 and 4 are connected to each other.

  The cable connection part 45 includes the substantially Y-shaped conductor connection body 46 that inserts the conductors 9 and 9 of the connection end parts 5 and 5 of the power cables 4 and 4 into the receiving part 46a for electrical connection, An epoxy insulator 47 made of an epoxy resin that covers the periphery of the conductor connection body 46 and performs an electrical insulation function, and the conductors 9 and 9 inserted into a receiving portion 46a having a mortar shape of the conductor connection body 46 are fastened and fixed. The metal wedge 48 and the wedge fastening metal fitting 49 tapered in a taper shape, and the pre-mold having a generally abacus-ball shape that is tightly fixed on the insulating layers 8 and 8 of the connection ends 5 and 5 of the power cables 4 and 4. The conductor 9 of the power cable 4 is connected among the insulator 50, the insulator compression fitting 51 for pressing the pre-mold insulator 50 on the insulating layers 8 and 8, and the receiving portion 46a of the conductor connector 46. Casting and an insulating plug 52 plugged into (indicated by symbol "46a '" in FIG. 8).

In the reference example 4 , the periphery of the connection end portions 5 and 5 of the power cables 4 and 4 from the cable connection portion 45 is a portion of the water shield tube 53 (each of which is wrapped around the outer peripheral surface of the odd-shaped epoxy insulator 47. A plurality of “partial water-impervious pipes 53a, 53b, 53c, 53d, 53e”) are combined and joined together.

  The water shielding pipe 53 is relatively rigid as a whole made of a water shielding resin such as plastic. This water-blocking resin is the same material as that used for the water-blocking layer 22 and the water-blocking tube 20B of the first embodiment, and a description thereof will be omitted. Of course, it is also preferable to use other water-proof materials.

  In FIG. 8, the partial water shielding pipe 53 a covers the outer periphery of the substantially Y-shaped epoxy insulator 47. Further, the connection end portions 5 and 5 of the power cables 4 and 4 and the premolded insulator 50 are inserted into the epoxy insulator 47, and the partial water shielding pipe 53 b and the partial water shielding pipe 53 c are connected to the connection end portion 5. , 5 covers from the part where the outer protective layers 27, 27 are peeled off to the part where the outer protective layers 27 are not peeled off, and has a tapered tubular structure.

  In addition, the other partial water-impervious pipes 53d and 53e are located in front of the partial water-impervious pipe 53b and the partial water-impervious pipe 53c so as to cover the connection end portions 5 and 5, and have a tapered tubular structure.

  The partial water-impervious pipe 53a, the partial water-impervious pipe 53b, and the partial water-impervious pipe 53c are fastened to each other by bolts 55 with a sealing member 54 such as an O-ring interposed between the mating surfaces therebetween.

  Moreover, the partial water-impervious pipe 53b, the partial water-impervious pipe 53c, and the other partial water-impervious pipes 53d and 53e are constructed by wrapping the insulating tape 56, the waterproof tape 57, and the insulating admixture 58, thereby insulating and watertight. Is secured.

  In addition, in the connection end portions 5 and 5 of the power cables 4 and 4, a semiconductive layer such as an ACP tape (cross-linked) is formed from the portion provided in the premold insulator 50 to the exposed portion of the shielding copper tape 28. Polyethylene semiconductive tape) 59 is provided.

  Further, the pressing structure of the pre-mold insulator 50 of the insulator compression fitting 51 has a substantially funnel shape with an open front end where the insulator compression fitting 51 abuts on the opposite side of the conductor connector 46 of the pre-mold insulator 50, together with it. The washer 60 that stops on the inner peripheral part (stepped part or the like) of the partial water-impervious pipes 53b and 53c, and the flange-like part at the base end of the insulator compression fitting 51 and the washer are advanced and retracted in the direction of the power cable 4 and 4 axis. A shaft 62 that is movably connected, and a fastening spring 63 that is externally attached to the shaft 62 and biases in a direction that opens the space between the washer 60 and the insulator compression fittings 51. Thereby, the pre-modal insulator 50 is always pressed against the conductor connector 46 side through the insulator compression fitting 51 by the biasing force of the spring 63, thereby eliminating the positional deviation. The shaft 62 is electrically connected to the shielding copper tape 28.

  The insulating plug 52 includes a substantially bowl-shaped insulating plug lid 64 that closes the opening of the receiving portion 46 a of the conductor connector 46, a washer 65 that stops on the inner periphery of the insulating plug lid 64, and the conductor connector 46. A pre-molded insulation plug body 66 to be fitted in the receiving portion 46a ′ to which the power cable is not connected, and the base end of the pre-mold insulation plug body 66 and the washer 65 can be moved forward and backward in the direction of the power cable 4 and 4 axes. It has a shaft 67 to be connected, and a fastening spring 68 that is externally attached to the shaft 67 and biases it in a direction that opens the space between the washer 65 and the pre-molded insulating plug body 66. As a result, the pre-molded insulating plug main body 66 is always pressed against the conductor connector 46 side by the biasing force of the spring 68 to eliminate positional displacement. The insulating plug lid 64 is made of the same material as the above-described water shielding pipe 53 (partial water shielding pipes 53 a to 53 e) and is also fastened to the partial water shielding pipe 53 a by bolts 55.

Since the water-blocking structure of the reference example 4 is configured as described above, the water-blocking tube 53 made of the above-described water-blocking resin made of plastic is used, so it is lighter than a water-blocking tube using a metal pipe, Good handling during work. Especially when connecting power cables installed in underground cable conduits in manholes, or when the water shielding structure covering the outer periphery of the entire Y branch connection of the power cable is large and heavy, etc. However, since it is easy to handle, it does not become a work load, does not take work time, and can reduce the work cost.

  The water shielding structure of the cable connecting portion of the present invention is a power cable for low voltage (less than 750 volts AC voltage) or a power cable for high voltage (750 volts to 6000 volts AC), and a crosslinked polyethylene insulated power cable. It is preferable to use or construct the cable connecting portion for (CV cable), but it can also be used for other voltages or other types of power cables to improve the water shielding property of the connecting portion.

It is sectional drawing in alignment with the axial direction of a power cable and a cable connection part which illustrates roughly the water shielding structure of the cable connection part which concerns on the 1st Embodiment of this invention. It is sectional drawing which follows the axial direction of the water shield shown in FIG. It is detailed sectional drawing which follows the axial direction of the concrete electric power cable and connection part of FIG. It is construction explanatory drawing of the water-impervious structure of a cable connection part. It is sectional drawing which follows the axial direction of the electric power cable and cable connection part which illustrate schematically the water-impervious structure of the cable connection part which concerns on the reference example 1. FIG. It is sectional drawing which follows the axial direction of the electric power cable and cable connection part which illustrate roughly the water-impervious structure of the cable connection part which concerns on the reference example 2. FIG. It is sectional drawing which follows the axial direction of the electric power cable and cable connection part which illustrate schematically the water-impervious structure of the cable connection part which concerns on the reference example 3. FIG. It is sectional drawing which follows the axial direction of the electric power cable and cable connection part which illustrate roughly the water-impervious structure of the cable connection part which concerns on the reference example 4. FIG.

Explanation of symbols

4, 4 Power cable 5, 5 Connection end 6 Cable connection 7, 7 Exterior 8, 8 Insulating layer 8a, 8a External semiconductive layer 8b, 8b Internal semiconductive layer 9, 9 Conductor 10 Water shielding tube (water shielding body)
11 Core 11a Opening 11b Groove 12 Conductor connecting pipe 20A, 20A Water shielding tube (water shielding body)
20B, 20B Water shielding pipe (water shielding body)
22 Water shielding layer 23 Shrinkable rubber elastic layer 23 Elastic layer 25 Adhering layer 27 External protective layer 27, 27 External protective layer 28, 28 Shielding copper tape 32 Insulating cylinder 33 Internal semiconductive layer 34 External semiconductive layer 34a, 34a Tape material 35 Ground wire 36 Shield layer 37 Ground metal fitting 40 Water proof tube 41 Water proof tube 42 Water proof tube 43 Water proof tube 44 Waterproof tape or waterproof tube 45 Cable connecting portion 46 Conductor connecting body 46a Receiving portion 47 Epoxy insulator 49 Tightening Metal fitting 50 Pre-modal insulator 51 Insulator compression metal fitting 52 Insulation plug 53 Water shielding pipe 53a, 53b, 53c, 53d Partial water shielding pipe 54 Seal member 55 Bolt 56 Insulation tape 57 Waterproof tape 58 Insulation compound 60 Washer 61 Core 62 Shaft 63 Spring 64 Insulation plug lid 65 Washer 66 Pre-molded insulation plug body 67 Yafuto 68 spring 101 Core 111 Core

Claims (3)

Strip the internal semiconductive layer from the external protective layer at the connection end of the power cable formed by the conductor, internal semiconductive layer, insulating layer, external semiconductive layer, shielding layer, and external protective layer to expose the conductor In this state, the conductors of both power cables opposed to each other for connection are connected by a connecting pipe, the periphery connected by the connecting pipe is covered with a substantially cylindrical insulator, and the inner periphery and outer periphery of the insulator are covered. A cable connection part water shielding structure for covering a cable connection part formed with a semiconductive layer by covering the outer periphery of the cable connection part with a water shielding body and preventing water from entering the cable connection part from the outside. ,
The outer diameter of the cable connection portion is larger than the outer diameter of the power cable,
The water shielding body does not include a metal material provided with a large diameter portion and a small diameter portion respectively corresponding to the outer diameter of the cable connection portion and the outer diameter of the power cable, and is a pair of rigid water shielding resin tubes. A water-impervious resin layer in which a water-impervious resin layer is wound in a cylindrical shape on the outer peripheral surface side of the cable connection portion, and a room-temperature-shrinkable rubber elastic body wound in a state of covering the outer peripheral surface of the water-impervious layer A first water shielding tube made of a shrinkable tube that does not contain a metal material comprising a layer,
Before connecting the conductors of the two power cables with a connecting pipe, the first water shielding tube is wound in a state where the water shielding layer is brought into contact with a removable cylindrical core and elastically expanded in diameter. And then send it to a position away from the connection end of the power cable on one side, and then cover the power cable on both the one side and the other side with a water shielding pipe respectively.
After forming the cable connection portion by connecting the two power cable conductors with a connecting pipe,
By a pair of impermeable tube in the water-impervious material, said cable connection part respectively over the connection end portion outer peripheral surface on both power cables made to face from the longitudinal center of the outer peripheral surface was covered in close contact with the first shielding A water shielding structure for a cable connecting portion, characterized in that a water tube is positioned near the center of the cable connecting portion to remove the core and cover the pair of water shielding pipes. The said water-impervious body further has a pair of 2nd water-impervious tubes which cover and cover both connection ends of the power cable from the pair of water-impervious tubes. Waterproof structure for cable connection. Strip the internal semiconductive layer from the external protective layer at the connection end of the power cable formed by the conductor, internal semiconductive layer, insulating layer, external semiconductive layer, shielding layer, and external protective layer to expose the conductor In this state, the conductors of both power cables opposed to each other for connection are connected by a connecting pipe, the periphery connected by the connecting pipe is covered with a substantially cylindrical insulator, and the inner periphery and outer periphery of the insulator are covered. A method for forming a water shielding structure for a cable connection part, wherein the outer periphery of the cable connection part is covered with a water shielding body and water is prevented from entering the cable connection part from the outside. Because
The outer diameter of the cable connection portion is larger than the outer diameter of the power cable,
As a water shielding body, a pair of water shielding pipes made of a rigid water shielding resin pipe not including a metal material provided with a large diameter portion and a small diameter portion corresponding to the outer diameter of the cable connection portion and the outer diameter of the power cable, respectively. A water-impervious resin layer in which a water-impervious resin layer is wound in a cylindrical shape on the outer peripheral surface side of the cable connection portion, and a room-temperature-shrinkable rubber elastic body wound in a state of covering the outer peripheral surface of the water-impervious layer A first water shielding tube made of a shrinkable tube that does not contain a metal material made of a layer,
Before connecting the conductors of the two power cables with a connecting pipe, the first water shielding tube is wound in a state where the water shielding layer is brought into contact with a removable cylindrical core and elastically expanded in diameter. A first step of feeding the product to a position away from the connection end of the power cable on one side;
A second step in which both the power cables on one side and the other side are respectively covered with a water shielding pipe and sent to a position away from the connection end;
A third step of connecting the power cable conductors to each other by a connecting pipe to form the cable connecting portion;
A fourth step of closely covering each of the connecting end portions of the power cables facing each other from the outer peripheral surface portion in the longitudinal direction of the cable connecting portion by a pair of water shielding pipes in the water shielding body; ,
A fifth step of positioning the first water shielding tube in the vicinity of the center of the cable connecting portion to remove the core and covering the pair of water shielding tubes. Formation method of water structure.

Images