EP1118031A1

EP1118031A1 - Helical rod and method for the production thereof

Info

Publication number: EP1118031A1
Application number: EP99970169A
Authority: EP
Inventors: Ernst Mayr; Thomas Müller; Thomas Ottmann
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1998-10-02
Filing date: 1999-10-01
Publication date: 2001-07-25
Also published as: WO2000020909A1

Abstract

In the case of most known A1 spirals that are used to go round the mast of an aerial line, the ADL cable that passes through the spiral at the top of the mast is often damaged in the region where transition occurs with the ground wire. This can be avoided by manufacturing the helical rod (1) that acts as a guide spiral out of electrically non-conducting/insulating materials, whereby the helical rod can consist of a resin-impregnated spiral-shaped bundle (21) of glass fibers or glass fiber yarns, and a PE sheath (22,23), especially a sheath consisting of two layers, around said bundle.

Description

description

Spiral rod and process for its manufacture

The invention relates in particular to a spiral rod for guiding and / or holding an air cable containing optical transmission elements in the area of the mast of an overhead line.

In order to establish a simple, fast and therefore inexpensive connection between buildings, districts, localities or distribution nodes, fiber optic (FO) air cables are being used more and more frequently. Self-supporting air cables and so-called ADL cables (All-Dielectric-Lash cables) are used. While a self-supporting aerial cable is equipped with metal-free, concentrically arranged strain relief elements ("All-Dielectric-Self-Supporting" cable or ADSS cable) or with a molded steel suspension cable (Figure 8 cable) that absorbs the tensile forces An ADL cable does not have its own support elements It is usually attached to the already installed earth or phase cable of the high-voltage overhead line by means of an adhesive / lashing tape (see, for example, WO 96/38892). Since the fiber-optic fibers lie in a helical shape with a defined excess length in the loose tube, the fibers are not mechanically stressed even under extreme conditions (storm, thick layer of ice).

When bypassing the mast of a high-voltage overhead line, the ADL cable held on the earth rope is often routed around the mast tip in an aluminum rod that is also attached to the earth rope and spirally coiled. Since under certain circumstances electricity also flows in the AI rod, the ADL cable in the area of the contact surfaces of the Al rod and earth rope can be damaged by burning or braising. To solve this problem, it has been suggested - to equip the center of the AI rod with an isolator element that prevents current flow (disadvantage: expensive),

- Isolate the contact surface of the AI rod on the earth rope by pulling on a shrink tube provided with an end cap (disadvantage: too expensive) and

- Attach the AI rod to the earth rope using specially made, insulating inserts with clamps (disadvantage: expensive, because it is custom-made).

The aim of the invention is to create a spiral rod with which, in particular, an ADL cable can be guided and / or held in the area of the mast of an overhead line without being damaged. This object is achieved by a spiral rod having the features of patent claim 1. In addition, a method for the cost-effective production of the spiral rod is to be specified.

Since the proposed spiral rod consists of electrically non-conductive or electrically insulating materials, the ADL cable cannot be damaged by current flow. The spiral rod preferably consists of a bundle of glass yarns or glass fibers (“glass rovings”) impregnated with resin, which is coated with a thin plastic layer. In addition, the spiral rod can also be provided with an outer plastic layer that defines the rod thickness, the one that forms the spiral rod the resin-wetted glass fiber / glass yarn bundle and the multilayer plastic sheath has an internal diameter of typically 8-25 mm, adapted to the earth rope.The lay length (: = distance between two vertices) of the spiral rod is 100-200 mm, preferably 150 mm, the approximately 2000 - 3000 mm long spiral rod can still be closed at the ends with a cap annealed at a temperature of approx. 80 ° C or cured at room temperature, the diameter of the spiral rod being able to be adapted in a simple manner to the diameter of the earth rope by appropriate dimensioning of the thickness of the metal tube used to produce the spiral structure.

UV-stabilized thermoplastics, in particular HDPE (high-density polyethylene) or UV-stabilized PP (polypropylene) can be considered as sheathing materials for the glass yarn / glass fiber bundle.

To produce the spiral rod, the glass yarn / glass fiber bundle, completely impregnated with resin and wetted, is provided simultaneously ("coextrusion") or successively ("tandem extrusion") with a multi-layer plastic sheath, then in one stroke on a rotating one in the direction of the longitudinal axis Longitudinally displaced tube wound and thereby formed into a spiral. The glass yarns / fibers usually run off the supply reels in a slightly braked manner, in order to then be completely impregnated with resin in a vessel by deflecting them on cylindrical elements. The bundle wetted with resin then passes through, for example, a nipple with 1-3 mm bore, which serves as a wiper for excess resin and defines the bundle thickness. The preliminary product produced in this way is provided with a jacket consisting of a thermoplastic material by means of extruders. The product then runs on a plate or lightly braked onto a supply spool.

This intermediate product is processed within the pot life determined by the resin used and, for example, 24 hours (: = period of time within which the structure consisting of the resin-wetted glass fiber / glass yarn bundle and the plastic jacket can still be formed into a spiral) by it on a tube with, for example, 8-25 mm in diameter and a length of, for example, 3-4 mm Wrapped in a flat lay and closed the ends. The lay length of the winding or spiral generated on the tube is typically 150 mm. The spiral rod produced in this way is then tempered or cured at room temperature.

Similar to the spiral rod described above, spirals can also be produced which, glued together, can be used as a so-called bottom spiral for the tensioning spiral of an ADSS cable.

The manufacturing process is as already described, but with the modification that the glass yarn / glass fiber bundle wetted with resin is only provided with a 0.4-0.7 mm thick plastic sheath that can be removed again after the structure has hardened. Several of the spirals produced in this way are then placed next to one another, pushed one inside the other, laid one turn after the other and glued together to form a likewise spiral-shaped unit, the length of which approximately corresponds to the length of a spiral. Then this unit, which typically consists of two to three spirals, is coated with an adhesive, sanded and provided with a weather and UV-resistant outer layer. PE and PP are particularly suitable as removable plastic. Weather resistance can be achieved, for example, by immersing the spiral package in a tar-epoxy mixture. Of course, these process steps can also be used in the manufacture of the spiral rod described above.

A one- or two-component resin, preferably epoxy resin with a sufficiently long pot life of, for example, 24 hours, is preferably used to impregnate the glass fibers. The inner and outer plastic sheath is also preferably applied in tandem extrusion. Further advantages and properties of the invention emerge from the following description and the drawings. It shows:

Figure 1 shows an embodiment of the spiral rod according to the present invention in a schematic side view.

FIG. 2 seen the spiral rod shown in FIG. 1 in the direction of its longitudinal axis;

3 shows a section through the spiral rod along the line A-A 'in Fig. 1.

Fig. 4 is an illustration of the process sequence for producing the spiral rod and

5 shows a representation of further process steps for the production of the helical rod.

The helical rod 1 shown schematically in FIGS. 1-3 serves to guide and hold an ADL cable when bypassing the tip of the mast of an overhead line. It consists of a glass yarn or glass fiber bundle 21 (outer diameter «1 - 3 mm) completely wetted with resin and a two-layer plastic antel 23/23, the thickness of which is in the range of about 1 - 2.5 mm. The inner diameter of the L = 2000-3000 mm long spiral, which is matched to the earth rope, is typically 8-25 mm, the lay length labeled S in FIG. 1, for example S = 100-200 mm, preferably S = 150 mm. Not shown is the ADL cable wrapped by the spiral, led past the top of the mast and fastened to the earth rope in the clamping fields.

FIG. 4 shows an arrangement for producing the spiral rod 1 shown in FIGS. 1 to 3. From n = 5-10 supply spools 2a-2n, filament-shaped glass yarns 4, glass fibers or a mixed material consisting of glass fibers and glass yarns are weave slightly braked unwound, approximated and fed to a vessel 6 in order to completely soak them there by repeatedly deflecting cylindrical elements with a one- or two-component resin, preferably epoxy resin (pot life approx. 24 hours). In the same vessel 6, the glass yarn / glass fiber bundle thus produced is also precoated with the resin. In the unit 8 following the vessel 6, the bundle is again wetted with resin and passed through a scraper. For example, a nipple is used as a wiper, the bore of which is one

Has a diameter of 1 - 3 mm. The bundle 4 'wetted with resin and calibrated in diameter, that is to say 1 -3 mm thick, is then provided with a multilayer jacket 22/23. This is done by means of extrusion, whereby both the technique of tandem extrusion and the process known as coextrusion can be used. In the example shown, the glass yarn / glass fiber bundle 4 'enters a first extruder 10, the spray head of which applies an approximately 0.4-0.7 mm thick plastic layer 22 (see FIG. 3), preferably made of HDPE or PP. After leaving the first

Extruder 10, the glass yarn / glass fiber bundle 4 'provided with the still hot inner jacket 22' is slightly cooled and fed to a second extruder 12, which is the outer, approximately 1.5-2.5 mm thick and preferably made of UV-stabilized HDPE or PP Applies outer jacket 23. A caterpillar take-off 18 generates the force required for the unwinding of the glass fiber / glass yarn 4 and the advance of the glass fiber / glass yarn bundle 4 '. The intermediate product 41 thus produced is temporarily stored in a plate or on a drum 14.

Within the pot life determined by the resin used and amounting to, for example, 24 hours, the preliminary product 41 (encased glass fiber / glass yarn bundle 4 ′) which is temporarily stored on the drum 14 and is still bendable or flexible is processed further by applying it to one shown in FIG Tube 16 coiled. The tube 16 has one of the earth rope thickness corresponding outer diameter of typically 8 - 25 mm and a length of a few meters depending on the number and type (lay length!) of the spiral rods to be manufactured. It is rotated around its longitudinal axis at a constant angular velocity and, at the same time, is shifted in the direction of the pipe longitudinal axis at a constant velocity. The spiral 42 produced in this way can then be tempered to solidify the resin at a temperature of approximately 80 ° C. or allowed to harden at room temperature.

The invention is of course not limited to the exemplary embodiments described. So you can still use the spirals or spirals in the following areas, as:

Fire / temperature protection for an optical cable

(closed wrapping of the cable with spiral rods); - Rodent protection for a cable (closed wrapping of the

Short length cables); - Marten protection (closed wrapping of vulnerable

Hoses or ignition cables);

Kick protection for cable harnesses or sensitive cables

(Wrapping the cable strands / lines within the hazardous area).

Claims

claims

1. Coil rod, especially for guiding and / or holding an air cable in the area of the mast of an overhead line, so that the coiled rod (1) consists exclusively of electrically insulating or non-conductive materials.

2. Spiral rod according to claim 1, d a d u r c h g e k e n n z e i c h n e t that it has a core (21) provided with a single-layer or multi-layer jacket (22, 23).

3. spiral rod according to claim 2, d a d u r c h g e k e n n z e i c h n e t that the core (21) consists of a resin-soaked bundle of glass fibers, glass yarns or blended fabrics and the jacket (22,23) made of plastic.

4. spiral rod according to claim 1, 2 or 3, d a d u r c h g e k e n n z e i c h n e t that it has the shape of a spiral.

5. spiral rod according to claim 4, d a d u r c h g e k e n n z e i c h n e t that the lay length of the spiral is in the range of 100 - 200 mm.

6. Spiral rod according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that it is annealed to harden the resin.

7. spiral rod according to one of claims 1 to 6, characterized in that the resin is cured at room temperature

8. Spiral rod according to one of the preceding claims, that the casing (22, 23) is made of a thermoplastic.

9. Coil rod according to one of the preceding claims, that the core (21) is impregnated with epoxy resin.

10. spiral rod according to one of claims 2 to 9, d a d u r c h g e k e n n z e i c h n e t that the jacket (22,23) is removably applied to the core (21).

11. A method for producing a particularly suitable for guiding and / or holding an air cable in the area of the mast of an overhead line spiral rod (1), characterized in that several elongated glass yarns (4), glass fibers or blended fabrics are approximated and soaked in resin that the resulting resin-wetted bundle (4 ') is provided with a single or multi-layer plastic jacket (22, 23) and that the covered bundle (4') is wound spirally on a tube (16) before the resin hardens.

12. The method according to claim 11, so that the glass yarns (4), glass fibers or mixed fabrics (4) are impregnated with resin in a vessel (6) by deflecting them on cylindrical elements.

13. The method according to claim 11 or 12, characterized in that the individual layers (22, 23) of the plastic jacket are applied simultaneously by coextrusion or in succession in spaced-apart extruders (10, 12).

14. The method according to any one of claims 11 to 13, so that the bundle (4) impregnated with resin passes through a stripper before it is coated with plastic.

15. The method according to any one of claims 11 to 14, so that the bundle (4 ') impregnated with resin and coated with plastic is tempered after winding onto the tube (16) or cures at room temperature.