WO2019110373A1

WO2019110373A1 - Cable with a fireproof layer

Info

Publication number: WO2019110373A1
Application number: PCT/EP2018/082669
Authority: WO
Inventors: Afsaneh Nishaburi; Gero SCHRÖDER
Original assignee: Südkabel GmbH
Priority date: 2017-12-06
Filing date: 2018-11-27
Publication date: 2019-06-13
Also published as: EP3721455A1; EP3721455B1

Abstract

A cable for laying in the ground, outdoors, in pipes or buildings, comprising a cable core (K) and a sheath which surrounds the cable core (K), wherein the sheath has a casing layer (12) and a flame-retardant and/or fire-retardant fireproof layer (13) and wherein the casing layer (12) and the fireproof layer (13) are coextruded, is to be specified in respect of the problem of a cable for laying in the ground, outdoors or in pipes but also in buildings, which cable, given a compact construction, is as stable as possible to mechanical actions and nevertheless exhibits as high a degree of resistance as possible in the event of fire, characterized in that the wall thickness (12a) of the casing layer (12) is, at least in sections, smaller than the wall thickness (13a) of the fireproof layer (13) which surrounds the casing layer (12), wherein a foil (9) is provided in a manner situated radially within and on the other side of the casing layer (12) and the fireproof layer (13), which foil has an overlapping region (11), or wherein a metal casing (7a) is provided in a manner situated radially within and on the other side of the casing layer (12) and the fireproof layer (13).

Description

Cable with fire protection layer

The invention relates to a cable according to the preamble of patent claim 1.

From US 2010/0051315 A1 a cable is known in which a relatively thick jacket layer is surrounded by a thinner fire protection layer. A cable in which a relatively thick fire protection layer with flame-retardant behavior is surrounded by a thinner Termigon layer is shown in EP 2 81 1 491 A1.

From DE 101 31 569 A1 cables are already known, which can be laid in the ground. These cables include a sheath that has a polyethylene sheath and a fire protection layer. The polyethylene sheath encloses a cable core. The polyethylene sheath and the fire protection layer are applied to the cable by coextrusion.

Cables with such a polyethylene sheath can be laid in water and in moist soil. The polyethylene jacket has a relatively high wall thickness against this background.

The fire protection layer, however, is relatively thin and has a wall thickness which corresponds to only one third to one quarter of the wall thickness of the polyethylene sheath. In practice, however, cases may occur in which a relatively large

Wall thickness of a fire protection layer should be present or even one

Cable outer sheath should consist exclusively of flame-retardant material.

Basically, the greater the wall thickness of the fire protection layer, the greater the resistance of a cable to fire, and the greater the thickness of a polyethylene sheath, the greater the

mechanical stability of the cable outer sheath, which is required during the laying of the cable, but also in the thermomechanical load cycle during operation.

However, if you apply a relatively thick fire protection layer on a relatively thick polyethylene sheath, the cable can be too bulky, too heavy and / or difficult to handle.

At the same time, however, there are also relatively high demands on the stability of the cable outer jacket, so that this intrinsic mechanical loads resulting from the structural design of the cable holds.

For example, there are constructions in which radially inside the

Kabelaußenmantels lying a film is provided which serves as a vapor or liquid barrier, in particular as a water vapor barrier, and can act in an unfavorable manner relative to the outer cable sheath.

If the film has an overlapping region, notch effects can act on the outer cable sheath from inside to radially outward on this or at individual points of the overlapping region or, in particular, at the end of the overlapping region, so that it can break or tear. The invention is therefore based on the object to provide a cable for installation in the ground, in air or in pipes, but also in buildings, which is as stable as possible against mechanical effects in a compact design and yet shows the highest possible resistance in case of fire.

The present invention achieves the aforementioned object by the features of patent claim 1.

First, it has been recognized that an overlap region of a film can unfavorably act radially outwards on a cable outer jacket, so that it can break or tear.

It has been recognized that this is particularly the case with designs in which the outer cable sheath is made exclusively of flame retardant material, if required by fire safety requirements. It has also been recognized that precisely this combination, consisting of a film as a water vapor barrier and an overlying pure fire protection layer, does not or only to a limited extent withstand the mechanical requirements of the cable.

It has also been recognized that high mechanical requirements can also be imposed on a cable with a metal jacket, which may have a smooth or corrugated surface. A cable, which has a cladding layer and an overlying fire protection layer, can be significantly improved in terms of stability compared to a cable, which has only one fire protection layer.

According to the invention has finally been recognized that the wall thickness of a cladding layer, which consists in particular of pure polyethylene, can be chosen smaller than the wall thickness of the fire protection layer, even if a shell or a cable outer sheath during installation or in the thermomechanical load cycle during operation mechanical

Affect loads.

It has also been recognized that although the fire retardant layer is more brittle than a pure polyethylene layer due to its filling with flame retardant fillers, it can still mechanically stabilize such a layer.

In particular, it has been recognized that a film at the end of her

Overlap area can develop notch effects. However, a relatively thin cladding layer, especially of pure polyethylene, can surprisingly withstand these notch effects, even if it is thin, and if the thin, inner cladding layer is surrounded by a relatively thick, outer fire-resistant layer. The in itself relatively brittle

Fire protection layer can stabilize a thin cladding layer surprisingly well against notch effects.

The notch effect on the overlap region of the film is defused by a thin jacket layer over the film, while at the same time the jacket layer provides a suitable substructure for the latter applied in coextrusion

Fire protection layer in terms of mechanical stability requirements.

According to a variant of the cable, the wall thickness of the jacket layer in a first section could be greater than the wall thickness of the fire protection layer and could be smaller in a second section. The first section can then be laid in a free area, in particular in the ground, the second section in an interior area, in particular in a building.

The cable is designed in this respect as a hybrid cable, which is suitable for several applications. Higher requirements for fire protection in a building and lower fire safety requirements

Outdoor areas can be satisfied by a single cable.

In a first section, therefore, only the cladding layer could be present, but no fire protection layer could be provided, wherein in a second section, both the cladding layer and the fire protection layer

are provided. This can save expensive material for the fire protection layer. Against this background, it is conceivable that the sections merge into one another continuously, with the wall thickness ratios continuously reversing along the cable. It is also a sudden reversal conceivable. A portion of the inverse of the wall thickness ratios and / or the other portions could be indicated by a mark

be marked so that the cable is laid correctly.

The wall thickness of the cladding layer could be at most 45%, preferably at most 25%, particularly preferably at most 10% of the wall thickness of

Fire protection layer amount.

As a radially inside the cladding layer and the fire protection layer lying film could be provided a metallic foil. The metallic foil could be purely metallic or comprise a metal-coated or coated plastic carrier layer. The film could also have an adhesive layer. The film serves as a water vapor barrier.

The film could be designed as aluminum foil. Aluminum is easy to process and light. The overlapping area of said film could be over

Arc segment of 10 ° to 45 ° extend. The length of the arc segment depends on the manufacture of the cable.

As lying radially inside and beyond the cladding layer and the fire protection layer metal shell could be provided a smooth metal sheath or a corrugated sheath. A metal jacket increases the stability of a cable. Smooth or corrugated metal shells can be made of lead, aluminum or other metallic materials, in particular sheet metal, with a smooth surface or in a corrugated design as a so-called corrugated sheath. These designs are characterized in contrast to layer coats in that they have no overlap area.

The metal shell could be made of aluminum or lead. These two metals have proven particularly useful in practice. A corrugated sheath is preferably made of aluminum. In general, however, a corrugated sheath could also be made of sheet metal.

The wall thickness of the cladding layer, which consists in particular of pure polyethylene, could be in the range 0.3-1 mm. These wall thicknesses have proven to be advantageous in order to withstand notch effects and movements of a film, in particular an aluminum foil.

The wall thickness of the fire protection layer could be in the range 0.5 - 5 mm. These wall thicknesses have proven to be advantageous in order to support a cladding layer against notch effects and movements of a film while meeting the fire protection requirements.

The cladding layer over the foil or a metal sheath could be off

Polyethylene or have polyethylene. polyethylene, especially high-density polyethylene (HDPE) is particularly suitable for cables to be laid in the ground.

The cladding layer could not have fire-retardant and / or flame-retardant materials or fillers. As a result, the sheath layer is very stable, elastic and not brittle. Alternatively or additionally, the

Sheath layer be made of pure polyethylene. Polyethylene is well suited for cables to be laid in the ground.

Radially lying outside the fire protection layer could optionally be provided a further thin, electrically conductive layer. This allows

Damage or failure during the installation of the cable can be detected. The wall thickness of this electrically conductive layer could be about 0.1 to 0.3 mm.

The cable described here could be used as a power cable and / or

High voltage cable for voltages in the range of 1 kV to 500 kV

Laying in the ground and / or at least partially used within buildings. The cable is sufficiently mechanically stable and keeps fires well.

The fire protection layer can be made of any suitable material or have this. The material is flame retardant and / or develops as little smoke as possible in case of fire. The material is halogen-free. The material could comprise polyethylene and / or ethylene vinyl acetate in which or about 20% -40% fillers are contained. As fillers can

Calcium carbonate, magnesium hydroxide or aluminum hydroxide are present. The above-described cladding layer without flame-retardant fillers,

especially from pure polyethylene, preferably does not have any of these or all of these fillers. In the drawing show

Fig. 1 is a schematic sectional view of a cable, which is a

Has film with an overlap area,

2a is an enlarged fragmentary view of another cable having two sections, wherein a portion is shown in which the wall thickness of the cladding layer is smaller than the wall thickness of the fire protection layer,

2b is an enlarged fragmentary view of another cable having two sections, wherein a portion is shown in which the wall thickness of the cladding layer is greater than the wall thickness of the fire protection layer,

3 shows a schematic longitudinal sectional view of the cable according to FIG. 2 a and FIG. 2 b, in which different wall thickness ratios of the jacket layer and the fire protection layer prevail in two sections,

Fig. 4 is a schematic longitudinal sectional view of another cable having a portion without fire protection layer, and

Fig. 5 is a sectional view of another cable, which a

Has metal shell.

Fig. 1 shows a cable, namely a ground cable, for installation in the ground, in air or in pipes, but also in buildings, comprising a cable core K and a shell. The shell surrounds the cable core. The shell acts as a cable outer sheath in this specific case. The cable core comprises in a concrete case the components that with the

Reference numerals 1 to 5 are marked. The cable further comprises windings 6, 8 and shield wires 7.

The cable includes a sleeve. In the specific case, the shell includes the

Components identified by the reference numerals 9 to 13. The shell surrounds the inner cable structure, which connects the components with the

Reference numerals 1 to 8.

The casing has a film 9, a jacket layer 12 made of polyethylene (HDPE) and a flame retardant and / or fire retardant fire protection layer 13. The cladding layer 12 and the fire protection layer 13 are coextruded. There is no additional adhesive between the cladding layer 12 and fire protection layer 13 is provided to connect them cohesively.

The wall thickness 12a of the cladding layer 12 of polyethylene is less than the wall thickness 13a of the fire protection layer 13, wherein radially inside and beyond the cladding layer 12 made of polyethylene, the film 9 is provided, which has an overlap region 1 1. The film 9 has two ends 10 which overlap one another. The film 9 is a separate component and is separated from the jacket layer 12 made of polyethylene. The film 9 is located radially further inside than the cladding layer 12 and the fire protection layer 13.

Figures 2a, 2b and 3 show an alternative cable which

Sectionally has the same structure as the cable of FIG. 1, but wherein the wall thickness 12a of the cladding layer 12 made of polyethylene in a first section A is greater than the wall thickness 13a of

Fire protection layer 13. In a second section B, the wall thickness 12a of the jacket layer 12 of polyethylene is then less than the wall thickness 13a of the fire protection layer 13. The wall thickness ratios are continuously reversed in a transition section C. In all sections A, B, C, the cladding layer 12 of polyethylene and the fire protection layer 13 are coextruded.

Fig. 4 shows a further alternative cable, which in sections has the same structure as the cable of FIG. 1, wherein in a first section A, only the cladding layer 12 is present and no fire protection layer. In a second section B, both the cladding layer 12 and the fire protection layer 13 are present.

The cable core K of the cables shown here can be constructed in the usual way. It may comprise conductor 1 made of copper or aluminum. A ladder can be round. A conductor may be multi-wire or formed in segments. In the specific case according to FIG. 1, FIG. 2 and FIG. 5, the conductor 1 is shown round and stranded from copper or aluminum. The conductor 1 is surrounded by an insulation 4, preferably made of polyethylene. Furthermore, screen wires 7 made of copper or aluminum can be provided for short-circuit control. It is also conceivable that optical fibers are provided.

The overlapping region 1 1 shown in FIGS. 1, 2 a and 2 b extends over an arc segment of 10 ° to 45 °. As radially inside and beyond the cladding layer 12 lying film 9, a metallic foil is provided. The film 9 is designed as aluminum foil.

The wall thickness 12a of the cladding layer 12 made of polyethylene is 1 mm in FIG.

1. The wall thickness 13a of the fire protection layer 13 is 3 mm in Fig. 1. The cladding layer 12 is made of polyethylene. Specifically, the cladding layer 12 is made of high density polyethylene (HDPE).

Radially outside the fire protection layer 13 lying may optionally be provided an electrically conductive layer. This layer can be through Application of a conductive material, in particular graphite, are generated. In this case, the graphite can be polished. Through another

Coextrusion of a conductive layer onto the fire protection layer may be extruded onto the conductive layer.

Fig. 5 shows another embodiment of a cable.

In this cable, the wall thickness of the cladding layer 12 is less than the wall thickness of the fire protection layer 13, wherein radially inside and beyond the cladding layer 12 and the fire protection layer 13 lying a metal jacket 7a is provided. The metal shell 7a may be smooth or wavy. The

Metal jacket 7a may be made of aluminum or lead or sheet metal.

The wall thickness 12a of the cladding layer 12 may be less than the wall thickness 13a of the fire protection layer 13 in sections or over the entire length of a cable.

The cables shown here are used as power cables and / or

High voltage cables for burial in the ground and / or at least partially used inside buildings or outdoors or in pipes.

reference numeral

1 conductor

2 wrapping

3 inner conductive layer

4 insulation

5 outer conductive layer

6 wrapping

7 shield wires

7a metal jacket

8 wrapping

9 foil

10 end of 9

1 1 overlap area of 9 12 sheath layer

12a wall thickness of 12

13 fire protection layer 13a wall thickness of 13

Claims

claims

A cable for burying in the ground, in air, in pipes or buildings, comprising a cable core (K) and a sheath which surrounds the cable core (K), wherein the sheath a cladding layer (12) and a

flame retardant and / or fire retardant fire protection layer (13) and wherein the cladding layer (12) and the fire protection layer (13) are coextruded,

characterized in that

the wall thickness (12a) of the cladding layer (12) is at least partially smaller than the wall thickness (13a) of the fire protection layer (13) surrounding the cladding layer (12), wherein radially inside and beyond the cladding layer (12) and the fire protection layer (13) lying a film (9) is provided, which has an overlap region (1 1), or wherein radially inside and beyond the cladding layer (12) and the fire protection layer (13) lying a metal jacket (7a) is provided.

2. Cable according to claim 1, characterized in that the wall thickness (12a) of the jacket layer (12) in a first section (A) is greater than the wall thickness (13a) of the fire protection layer (13) and in a second section (B) less ,

3. Cable according to claim 1, characterized in that in a first section (A), only the cladding layer (12) is present, but none

Fire protection layer (13) is provided, wherein in a second

Section (B) both the cladding layer (12) and the

Fire protection layer (13) are provided.

4. Cable according to one of the preceding claims, characterized

in that the wall thickness (12a) of the cladding layer (12) is at most 45%, preferably at most 25%, particularly preferably at most 10% of the wall thickness (13a) of the fire protection layer (13).

5. Cable according to one of the preceding claims, characterized

in that a metallic foil is provided as film (9) lying radially inside and beyond the jacket layer (12) and the fire protection layer (13).

6. Cable according to claim 5, characterized in that the film (9) is designed as aluminum foil.

7. Cable according to one of the preceding claims, characterized

characterized in that the overlap region (1 1) of the film (9) extends over an arc segment of 10 ° to 45 °.

8. Cable according to one of the preceding claims, characterized

in that a smooth metal sheath or a corrugated sheath is provided as the metal sheath (7a) located radially inside and beyond the sheath layer (12) and the fire protection layer (13).

9. Cable according to claim 8, characterized in that the metal jacket (7a) is made of aluminum or lead.

10. Cable according to one of the preceding claims, characterized

in that the wall thickness (12a) of the cladding layer (12) is in the range 0.3-1 mm.

11. Cable according to one of the preceding claims, characterized

in that the wall thickness (13a) of the fire protection layer (13) is in the range 0.5-5 mm.

12. Cable according to one of the preceding claims, characterized

in that the jacket layer (12) is made of polyethylene or has polyethylene.

13. Cable according to one of the preceding claims, characterized

characterized in that the jacket layer (12) has no fire-retardant and / or flame-retardant materials and / or is made of pure polyethylene.

14. Cable according to one of the preceding claims, characterized

in that an electrically conductive layer is provided lying radially outside the fire protection layer (13).

15. Use of a cable according to one of the preceding claims, as a power cable and / or high voltage cable for installation in the ground and / or at least partially within buildings.