EP2927912A1 - Flat cable with short circuit prevention in case of fire and use and manufacture of such a flat cable - Google Patents

Abstract

A flat cable (1) with short circuit avoidance in case of fire, even when laying on an electrically conductive support body has at least two cores (7, 7a) which run parallel to each other in a plane. The wires (7, 7a) each have a conductor (2) and a ring-shaped core insulation (3, 10), wherein in at least one of the wires (7) the core insulation (3, 10) directly on the wire conductor (2) extruded , in the event of fire comprises ceramic insulating material. An intermediate sheath (4) surrounds the cores (7, 7a) and engages between two cores (7, 7a) from one flat side of the flat cable to the other flat side. An outer casing (6) surrounds the intermediate casing (4) and defines the outer contour of the flat cable (1). At least one fire-resistant insulating layer (5) is arranged externally on the intermediate jacket (4); it lies between the intermediate casing (4) and the outer casing (6).

Description

FIELD OF THE INVENTION

The invention relates to a flat cable with short circuit avoidance in case of fire and the use and manufacture of such a flat cable.

BACKGROUND OF THE INVENTION

In larger buildings, transportation structures (such as tunnels) and ships, the evacuation time may be 30 minutes or more. These are therefore usually equipped with electrical emergency equipment that must be supplied in case of fire, at least for the evacuation time with electrical energy to allow evacuation. These include e.g. Smoke exhaust fan, emergency lighting, signs etc.

The suitability of an electrical installation for maintaining the power supply even under the action of fire is usually described by the term "functional integrity". Flat cables are basically particularly suitable for functional integrity, as shown in the publication EP 2 375 505 A1 is known. In conventional round cables, the wires are twisted together. In case of fire, therefore, after the conductor insulation has burnt, the wire conductors come to lie at the intersection points. In the case of flat cables, however, core conductors run without crossing points in the cable. Therefore, a flat cable behaves in terms of the risk of short circuit from the outset cheaper. In addition, a flat cable has virtually no internal stress, as they are typical for twisted round cable, so has no pronounced tendency as the round cable to discard when burning the insulation.

In the prior art, there are various proposals for fire-resistant flat cable. The already mentioned document EP 2 375 505 A1 describes, for example, a flat cable, in which the wire conductors are included without the usual wire insulation of a fire-resistant insulating layer directly on the metallic surface of the wire conductors. The insulating layer comprises an upper and a lower half, which surround the wire conductors in each case in cross-section semicircular. Between the core conductors are the fire - resistant insulating layers in the middle plane of the Flat cable glued together, ie between the wire conductors is fire-resistant fire-resistant insulating material arranged.

The publication US 2009/0078446 A1 describes another fire-resistant cable, in which the core conductors are surrounded by a core insulation as a whole. This common core insulation acts as a cladding mechanically fixing the conductor conductor. The common insulation is made of a polymer that can be converted in case of fire at least on the surface in a ceramic state. The common insulation is surrounded by an outer jacket, which leaves fire-resistant ash in case of fire.

The publication JP H01117204 A describes a fire-resistant flat cable in which the individual wire conductors (strands) are wrapped with a glass mica tape. The conductors are wound side by side and are held together by a surrounding layer of polyethylene. This layer is surrounded by a fire-resistant coat, which in turn is surrounded by a fabric cover.

In tunnels and buildings, cables are often used on metallic cable support systems, e.g. metallic cable racks lying out.

SUMMARY OF THE INVENTION

The present invention provides a flat cable with short circuit prevention in case of fire even when laying on an electrically conductive support body. The flat cable comprises at least two cores, an intermediate sheath, at least one fire-resistant insulating layer and an outer sheath. The at least two wires run parallel to each other in a plane. The cores each have a core conductor and a core insulation which is annular in cross-section, wherein in at least one of the cores the core insulation comprises insulating material extruded directly onto the core conductor and insulating in case of fire. The intermediate sheath encloses the cores as a whole and thereby encloses the core insulation directly on the outside thereof. The intermediate sheath engages between two cores of a flat side of the flat cable to the other flat side. The outer jacket surrounds the intermediate jacket and defines the outer contour of the flat cable. At least one fire-resistant insulating layer is arranged between the intermediate casing and the outer casing.

Another aspect relates to the use of a flat cable described above on an electrically conductive support body, wherein the flat cable is oriented so that the at least one fire-resistant insulating layer comes to rest between the wires and the support body.

Another aspect relates to a method for producing a flat cable with short circuit prevention in case of fire, even when laying on an electrically conductive cable support. The method comprises producing cores with a core insulation arranged directly on a wire conductor, ring-shaped in cross-section, applying an intermediate sheath to at least two cores, applying at least one fire-resistant insulating layer to the outside of the intermediate sheath and applying an outer sheath to the intermediate sheath together with the fire-resistant insulating layer , The production of cores with a core insulation arranged directly on a conductor, in cross-section annular insulation comprises producing the core insulation, an encapsulation of the core conductor with an insulating in the event of fire insulating material with an extruder. The intermediate sheath is applied to a plurality of cores running parallel to one another in a plane, of which at least one core is equipped with the insulating in the event of fire insulating material, so that it encloses the cores in total, while the core insulations wrapped directly on the outside and between two Veins from one flat side of the flat cable to the other flat side passes through. The outer jacket defines the outer contour of the flat cable.

Other features will be apparent from the disclosed apparatus and methods, or will become apparent to those skilled in the art from the following description of the examples and the accompanying drawings.

GENERAL EXPLANATION, ALSO CONCERNING OPTIONAL EMBODIMENTS OF THE INVENTION

The flat cable according to the invention is provided for short-circuit avoidance in case of fire, even when laid on an electrically conductive supporting body, for example a metallic (i.e., electrically conductive) cable rack.

Short circuit can be caused by electrical contact between two wire conductors. In the event of a fire, fire-resistant cable insulation does not burn due to high ambient temperatures or direct flame exposure.

In embodiments as a single-phase flat cable this has e.g. two or three wires (a live wire, a wire for the neutral wire and possibly a wire for the protective conductor), in embodiments as a three-phase flat cable are e.g. four or five cores (one core per phase, and one conductor for the neutral conductor and, if necessary, one conductor for the protective conductor). The individual wires include a wire conductor and a core insulation.

The individual core conductors of the flat cable have a cross-sectionally annular core insulation. In the case of the lead-carrying conductor (s) and optionally also the neutral conductor and / or the protective conductor, ie at least one core of the flat cable, the core insulation comprises, in the event of fire, ceramising insulating material which is extruded directly onto the conductor surface, ie without additional intermediate layer. In case of fire ceramizing insulating materials are known in the art, such as from P. Eyerer et al., Polymer Engineering Technologies and Practice, Springer-Verlag, 2008, p. 111 . Keyword "Ceramizing polymers ", and KW Thomson et al., In the firing line, European Coatings Journal, 2006, 12, pp. 34-39 , The insulating material is, for example, a thermoplastic with one or more ceramizing additives in case of fire, which form a ceramic crust when the plastic burns. The additives may be, for example, silicate material, metal or semimetal oxides (such as SiO ₂ , Al ₂ O ₃ ), or other suitable ceramizing materials such as zinc borate, or mixtures thereof. The ceramizing plastic is applied, for example as a melt directly to the surface of the wire conductor, and surrounds the wire conductor in cross-section annular. If, in case of fire, the plastic of the core insulation burns off, the ceramizing additive forms the said insulating crust, which then still ensures a certain electrical insulation.

Furthermore, the flat cable comprises an intermediate sheath made of plastic, which surrounds the outside of the core insulation, for example, the intermediate sheath can be extruded onto the core insulation, and enclose the cores in total. This creates a substantially rectangular plastic block, in which the individual wires are embedded. Due to the essentially rectangular plastic block, a plastic penetration occurs between the cores arranged in parallel. The passage extends between each two of the wires from one of the flat sides of the plastic block to the other flat side. The penetration ensures a spacing between the centers of the individual wires, which is larger than the diameter of a wire. Thus, the veins do not touch, but run under one Distance from each other, and are defined by the swept intermediate sheath held at this distance. The thus ensured spacing of the wires acts preventively in case of fire against short circuit, since the wires are already apart from the outset and so less easily touch in case of fire, ie, in electrical contact with each other can. The ensured by the penetration, relatively large vein spacing thus acts with the other described measures for short circuit prevention (ceramizing core insulation, fire-resistant insulating layer outside the intermediate sheath) together.

Due to the above-mentioned properties favorable for fire-functional integrity of a flat cable, this version is equipped with spaced wires with ceramic core insulation in case of fire to avoid short circuits between two wire conductors sufficient. In case of fire, two ceramic core insulation layers are located between two live core conductors. It has been recognized, however, that with flat cables running on metallic cable support systems, short circuits can also occur between one or more core conductors and the electrically conductive support bodies. Between a core conductor and such an electrically conductive support body is in the event of fire, only a ceramicized core insulation. On the one hand to keep the thickness of the ceramic core insulation as low as possible and on the other hand to ensure sufficient electrical insulation in case of fire down to an electrically conductive support body, it was recognized that it is favorable to provide a further short-circuit preventing measure directed thereto for the case of fire.

As additional protection against short circuits in case of fire by contact of wire conductors with an electrically conductive supporting body of the flat cable, e.g. a cable tray made of metal, the flat cable comprises at least one fire-resistant insulating layer.

In some embodiments, the flat cable comprises a single fire-resistant insulating layer, in other embodiments, it comprises more than one such insulating layer, wherein the plurality of layers, for example, lie directly on one another and thus form a layer structure.

The at least one insulating layer is non-flammable and dimensionally stable upon exposure to fire, i. it retains its insulating property even in case of fire, for example in a kiln test at 750 ° C for at least 15 min at.

The fire-resistant insulating layer or the plurality of fire-resistant insulating layers are arranged outside of the intermediate sheath; It ensures (or ensure) so that in case of fire, an electrical insulation between the wires and the metallic support body of the flat cable. The fire-resistant insulating layer extends e.g. over the entire surface between the respective outer wires of the flat cable and thus covers all the wires of the flat cable together with the wire gaps.

This structure is surrounded by an outer protective layer, the outer sheath, which defines the outer contour of the flat cable and, where appropriate, gives the cable resistance to aggressive substances and mechanical damage during normal operation and can be marked and labeled in color.

The cable described thus avoids not only direct short circuits between adjacent wires in case of fire, but also due to the reinforced fire-resistant equipment for flat side and those to a metallic support body. It is because of the relatively economical use of ceramizing plastic cheaper than known cable to produce.

As has already been stated, the ceramic insulating material of the wire insulation in some embodiments comprises a plastic which is mixed with keramiserendem additive. Here, the plastic, a flexible, non-halogenated thermoplastic polymer such as polyethylene, polypropylene, ethylene-propylene-diene (EPDM), acrylonitrile-butadiene-styrene, polyamides, polylactate, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, polystyrene, polyetheretherketone, or mixtures thereof, which is mixed with the ceramizing additive. The core conductors can be overmolded with a melt of the ceramizing additive added plastic, so as to obtain the wires including the ceramic core insulation. As mentioned above, suitable, in case of fire ceramizing additives are known; see for Example P.Eyerer et al., Polymer Engineering Technologies and Practice, Springer-Verlag, 2008, p. 111 . Keyword "Ceramizing polymers ", and KW Thomson et al., In the firing line, European Coatings Journal, 2006, 12, pp. 34-39 , The ceramizing additives are, for example, silicate material, metal or semimetal oxide (such as SiO ₂ , Al ₂ O ₃ ), or other suitable ceramizing material such as zinc borate, or mixtures thereof.

In some embodiments, the ceramizing additive forms in case of fire, i. at temperatures at which the plastic in which the additive is burned off, an insulating crust. In other words, the plastic is mixed with one or more crusting agents that leave a stable, non-conductive ash in case of fire. -

In some embodiments, in the at least one core, which is equipped with in the event of fire keramisierendem insulating material, the core insulation in its entire thickness of the extruded, in the event of fire keramisierendem insulating material. This leads to a relatively thick insulating crust in case of fire.

In other embodiments, the core insulation in the at least one core with ceramic in the event of fire insulating material, however, constructed in two layers. Only an inner part of the core insulation is made of the extruded, in the event of fire ceramizing insulating material, while an outer part of the core insulation is made of non-fire-resistant plastic, so burns in case of fire. As mentioned above, a flat cable has inherently favorable fire performance characteristics (due to the absence of conductor crossovers and internal stresses); Due to these properties and by cooperation with the fire-resistant insulating layer outside the intermediate sheath, it is sufficient to form only a part of the core insulation fireproof. In order for the insulating crust formed by fire to lie directly on the wire conductor, it is the inner layer of the two-layered wire insulation that is produced from the insulating material which ceramises in the event of fire. By this measure, therefore, the required amount of ceramic insulating material is minimized. On the other hand, the equipment of the cores with a non-fire resistant plastic sheath in addition to the fire-resistant facilitates that the conditions of normal operation (non-fire), such as strength, elasticity, resistance to aggressive substances, etc.) to core insulation can be more easily satisfied than alone with a fire resistant cladding.

It can be seen from the above statements that in at least one of the cores of the flat cable, the core insulation comprises an insulating material which ceramises in the event of fire. This expresses the fact that not all wires of the flat cable have to be equipped with this fire-resistant insulating material, but includes the possibility of a fire resistant equipment of all wires.

In some embodiments, all the wires of the flat cable are equipped with in the event of fire keramisierendem insulating material.

In other embodiments, however, only a portion of the cores of the flat cable is equipped with in the event of fire keramisierendem insulating material, while one or more cores of the flat cable, the core insulation is made entirely of non-fire-resistant plastic, so that it completely burns in case of fire. The non-fire-resistant cores may be those cores which are intended to carry no voltage, that is, for example, around the conductor forming the protective conductor. Namely, fire-resistant insulation is not required with such a core because it is at the same (earth) potential as e.g. an electrically conductive cable rack is located, and therefore in case of loss of insulation in case of fire, a conductor contact e.g. with the cable rack has no short circuit result. By this measure, therefore, the required amount of ceramic insulating material is minimized.

Strictly speaking, the core forming the neutral conductor is not exactly at ground potential, since in the case of a three-phase system (and not least in a single-phase system) which is not exactly phase-compensated, a current flow takes place in the neutral conductor, the i.A. leads to a non-zero voltage of the neutral to ground. In some embodiments, therefore, the core forming the neutral conductor is equipped with insulating in the event of fire Keramisierendem. In other embodiments, however, the voltage applied to the neutral voltage is considered to be negligible, so that (even) the core forming the neutral conductor is not equipped fireproof.

In some embodiments, the intermediate sheath is made of a ceramizing in case of fire insulating material or plastic.

By equipping the flat cable with the fire-resistant insulating layer outside the intermediate sheath but can be dispensed with such a ceramic version of the intermediate sheath. In some embodiments, the plastic of the intermediate jacket is so a non-fire-resistant plastic that burns in the event of fire. The intermediate sheath thus leaves, in contrast to the wire insulation of the live conductors, no insulating crust, or other insulating layer. Thus, in the event of fire, the intermediate sheath does not provide any fire-resistant insulation (such as additional encrustation) in the region of the penetration between the cores, in addition to that of the core insulation. The intermediate coat thus makes no contribution to the fire protection; it rather serves (only) to stabilize the flat cable and the spacing of the wires in normal operation (ie in non-fire). In case of fire, the wires come to rest with the insulating crust formed from the wire insulation on the fire-resistant insulating layer.

The same applies to the outer sheath: This can also be made of a ceramizing in case of fire insulating material or plastic. By equipping the flat cable with the fire-resistant insulating layer outside the intermediate sheath can be dispensed with such a ceramic version of the outer sheath. In some embodiments, the plastic of the outer shell is therefore a non-fire resistant plastic that burns in the event of fire. The outer sheath thus leaves, in contrast to the wire insulation, no insulating crust, or other insulating layer.

In some embodiments, the intermediate jacket is extruded directly and without an intermediate layer on the outside, so the surface, the core insulation. A plastic melt is extruded directly onto the parallel juxtaposed wires and thereby forms the above-described penetration between two cores and ensures their spacing. Thus, only the plastic of the passage of the intermediate sheath is located between two wires outside of the ring core in cross-section insulation. The thus ensured spacing of the wires acts preventively in case of fire against short circuit, since the wires are already far apart from the outset and thus less easily touch, i. can be in electrical contact with each other, can.

In some embodiments, the spacing of adjacent wires from outside to outside of the adjacent wire insulation is at least equal to the wire radius. In the event that the adjacent wires have different radii, the "core radius" is understood to mean the average radius of the two wires. This relatively large vein spacing is particularly preventive against short circuit, and thus cooperates with the other measures described for short-circuit prevention.

In some embodiments, the fire-resistant insulating layer completely surrounds the intermediate jacket in the form of one or more windings, ie it is present on both flat sides of the flat cable.

In other embodiments, the fire-resistant insulating layer is formed as a two-part insert on the two flat sides in each case between the intermediate jacket and the outer jacket. In this case, the fire-resistant insulating layer may be provided only on the flat sides of the flat cable (i.e., not on the narrow sides thereof), or may extend to the area of the narrow sides.

In yet other embodiments, the flat cable, however, on only one side of a fire-resistant insulating layer. Also in these embodiments, the fire-resistant insulating layer may be provided on only one flat side of the flat cable (i.e., not on the narrow sides thereof), or may extend in the region of the narrow sides.

In the embodiments with fire-resistant insulating layer on only one of the two flat sides of the flat cable is in laying the flat cable on an electrically conductive support body of the flat cable, e.g. Metal planks to ensure that the cable with the said flat side with the fire-resistant insulating layer to the electrically conductive support body, i. oriented downwards. This ensures that the fire-resistant insulating layer is in case of fire between the wire conductors and the electrically conductive support body.

In order to facilitate the said orientation of the flat cable with the fire-resistant insulating layer in the latter embodiments, the outer sheath in some of these embodiments, no 180 ° symmetry to the side with the at least one fire-resistant insulating layer by an asymmetrical configuration of the outer contour of the outer shell of to make outward visible.

The following explanation: A flat cable, in which the two possible orientations would be indistinguishable from the outside, had a 180 ° symmetry about an axis of symmetry in the middle of the cable in the cable longitudinal direction (because the two orientations correspond to a rotation of the cable through 180 ° about the said axis of symmetry ). 180 ° symmetry means that a Flat cable can be turned around this axis, without its outer cross-sectional shape would differ in these two orientations.

In order to break the 180 ° symmetry, in these embodiments, for example, various edge roundings of the essentially rectangular contour of the flat cable and / or an index nose and / or a recess on one or more of the outer sides of the outer jacket can be used. By such a refraction of the symmetry is visible from the outside, how to orient the flat cable, so that the fire-resistant insulating layer is below.

In some embodiments, the at least one fire-resistant insulating layer comprises a fire-resistant and electrically insulating mineral material, which prevents electrical contact between the wire conductors and the support body for the flat cable in case of fire. In some embodiments, the mineral is a silicate.

For example, the fire-resistant insulating layer comprises a mica layer. Mica is a fissile aluminosilicate that is electrically insulating and fire resistant.

For ease of processing, in some of the mica layer designs, the refractory insulating layer may be a flexible carrier tape, e.g. include a glass cloth tape. The mica layer may be glued to the flexible carrier tape. The flexible carrier tape is e.g. applied together with the mica layer in the preparation of the flat cable on the intermediate jacket, e.g. ironed.

The present description also relates to a use of the flat cable, in which it is designed on an electrically conductive support body. It is oriented so that the at least one fire-resistant insulating layer between the wires and the support body comes to rest. If the flat cable has a fire-resistant insulating layer on both flat sides, then it does not matter with which orientation the flat cable is laid. If, on the other hand, the fire-resistant insulating layer has only one flat side, the cable is oriented with the insulating layer to the carrier body, as mentioned above.

It is also possible to lay several flat cables in parallel one above the other, ie to stack the flat cables on the support body. Even with this use is in embodiments with only on a flat side existing fire-resistant insulating layer, the orientation of the stacked flat cable chosen so that each side is the fire-resistant insulating layer on the underside of the flat cable.

In the present specification, an example of a suitable method for manufacturing the flat cable described above is also given. The method comprises the overmolding of core conductors with insulating in the event of fire insulating material, with an extruder. The core insulation thus obtained encloses the conductors therefore with an annular cross-section directly on the surface thereof and thus represents a continuous fire-resistant protective layer with respect to the conductor surface.

Then the intermediate jacket is made. In some embodiments of the method, this is also done by extrusion, e.g. the individual wires are parallel to each other in a plane from each other with an extruder with a plastic coating so that the plastic envelops the wires as a whole. The plastic melt is e.g. Extruded directly onto the outside of the wire insulation and produces a substantially rectangular plastic block in which the wires are cast, the intermediate sheath. In this case, as described above, the wires are so far apart that the intermediate sheath penetrates the cores from one of its flat sides to the opposite flat side.

Then, the at least one fire-resistant insulating layer is applied to the outside of the intermediate jacket. The refractory insulating layer may be bonded to the intermediate jacket, for example, by being glued or ironed onto the intermediate jacket. It is also possible to first add insulating layer and intermediate sheath without such connection, i. put on each other, and to provide a connection between the two only by the outer sheath, the e.g. can also be extruded.

Finally, the outer sheath is applied to the intermediate sheath together with the fire-resistant insulating layer; it defines the outer contour of the flat cable, depending on the arrangement of the fire-resistant insulating layer between the intermediate jacket and outer jacket. As mentioned, in some embodiments of the method, this can also be done by extrusion, by providing the intermediate sheath together with the cores lying therein together with the fire-resistant insulating layer with an extruder with a plastic coating which forms the outer sheath.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1

einen schematischen Aufbau einer Ausführungsform des Flachkabels in einer schrägen Seitenansicht zeigt,

Fig. 2

schematisch einen Querschnitt der Ausführungsform von Fig. 1 zeigt,

Fig. 3

eine Ausführungsform einer Kabelpritsche zur Verlegung des Flachkabels zeigt,

Fig. 4

schematisch einen Querschnitt einer Ausführungsform des Flachkabels mit zweischichtigen Aderisolierungen bei einem Teil der Adern auf einer Kabelpritsche im Nicht-Brandfall zeigt,

Fig. 5

schematisch einen Querschnitt der Ausführungsform des Flachkabels von Fig. 4 auf der Kabelpritsche während bzw. nach einem Brandfall zeigt,

Fig. 6

schematisch eine beispielhafte Ausführungsform eines Verfahrens zur Herstellung des Flachkabels zeigt.

In the following, examples of the present invention are also explained with reference to the attached drawing, in which:

Fig. 1

shows a schematic structure of an embodiment of the flat cable in an oblique side view,

Fig. 2

schematically a cross section of the embodiment of Fig. 1 shows,

Fig. 3

shows an embodiment of a cable rack for laying the flat cable,

Fig. 4

schematically shows a cross section of an embodiment of the flat cable with two-layer core insulation in a part of the wires on a cable rack in the event of fire,

Fig. 5

schematically a cross section of the embodiment of the flat cable of Fig. 4 on the cable rack during or after a fire,

Fig. 6

schematically shows an exemplary embodiment of a method for producing the flat cable.

The drawings and the description of the drawings relate to examples of the invention and not to the invention itself.

DESCRIPTION OF EXEMPLARY EMBODIMENTS ACCORDING TO THE DRAWING

Fig. 1 shows an exemplary embodiment of a flat cable 1 with short circuit avoidance in case of fire, even when laying on an electrically conductive support body.

The flat cable 1 has in the three-phase system shown here by way of example, for example, five parallel wires 7, which run side by side in a plane at a fixed distance from each other. Each of these five wires 7 consists of a metallic core conductor 2 in the middle and a core insulation surrounding this ring 3. In the in Fig. 1 As shown, the core insulation 3 are each constructed of a single layer of insulating material. The insulating material is mineral staggered plastic. The minerals burn at typical temperatures, above the normal operating temperature, when the plastic matrix in which they are located burns (above 200 ° - 300 ° C), a ceramic crust, which prevents a short circuit between the wire conductors 2. The same applies to two-layer core insulation according to the embodiment of 4 and 5 for the inner layer.

The three left veins 7 are used in the in the Fig. 1 . 2 . 4, 5 shown flat cable 1, for example, as a phase conductor, while the right center of the core 7, for example, the neutral conductor and the right outside vein 7, for example, the protective conductor. For some of the Fig. 1 and 2 In the embodiments illustrated, all cores 7 are of identical design, ie they have the same conductor cross-section, the same fire-resistant (ceramizing) core insulation and the same core spacings. Others by the Fig. 1 and 2 In contrast, only the three live wires, that is, the phase conductors are equipped with fire resistant (ceramizing) wire insulation, while the core insulation of the protective conductor is made entirely of non-fire resistant plastic. The neutral conductor is generally not completely de-energized; in some embodiments, it has fire-resistant core insulation (such as the phase conductors), but in other embodiments, non-fire-resistant core insulation (such as the protective conductor).

The individual wires 7 are embedded in a non-fire resistant intermediate sheath 4 made of plastic. The intermediate casing 4 surrounds the wires 7 on all sides and in each case forms a passage between the individual wires 7 from one of the flat sides of the flat cable 1 to the other flat side.

The penetration of the intermediate sheath 4 ensures the parallel spacing of the wires 7 in normal operation and ensures in case of fire due to the distance between the wires 7 for additional short-circuit avoidance between the individual wire conductors. 2

Due to this compact construction of the cable interior with a continuous plastic block formed by the intermediate jacket 4, in which the individual wires 7 are embedded, a support structure is created which gives the entire flat cable 1 stability. Through the combination of the two flat sides on the penetration lifting, ie peeling, the top or bottom of the flat cable 1 is prevented.

On one of the two flat sides of the flat cable 1, the underside of the flat cable 1, is located outside of the intermediate sheath 4, a fire-resistant insulating layer 5, e.g. made of mica, if necessary on a glass cloth tape. In case of fire, when the intermediate jacket 4 and the outer jacket 6 mentioned below are completely burned down, this insulating layer 5 provides a remaining electrical insulation between the wires 7 and the optionally conductive contact surface of the flat cable 1.

The entire structure described is finally surrounded by a non-fire resistant outer sheath 6 made of plastic, which protects the flat cable 1 from aggressive substances and mechanical damage.

The outer sheath 6 gives the flat cable 1 its outer contour. The flat cable 1 has an index nose 8 on one of the two narrow sides of the outer jacket 6. The asymmetrical outer contour of the flat cable 1, when later laying the flat cable 1, ensures that the side with the fire-resistant insulating layer 5, i. the mica layer is visible from the outside, so that the flat cable 1 is laid with this layer 5 down.

Fig. 2 shows a schematic cross section of the exemplary embodiment of a flat cable 1 with short circuit prevention in case of fire, even when laying on an electrically conductive support body, which is described above.

The flat cable 1 has e.g. five wires 7, wherein the wires 7 have a designated "21" diameter. The distance "22" between the centers of two adjacent wire conductors 2 is at least 1.5 times the wire diameter 21.

The space between two adjacent wires 7 is filled by the passage of the intermediate jacket 4 from a flat side of the flat cable 1 to the other. The intermediate casing 4 completely surrounds all wire insulation 3. At the side edges of the intermediate jacket 4 have fillets 25.

On a flat side of the flat cable 1 is located on the outside of the intermediate jacket 4, a fire-resistant insulating layer 5 in the form of a mica layer having a width 28 which extends at least from the outer edge of one of the two outer wires 7 to that of the other outer wire 7 and so electrical insulation between the wires 7 and one electrically conductive substrate in case of fire (ie burned intermediate jacket 4 and outer jacket 6) guaranteed.

Said electrically conductive support body for the flat cable 1 may, for example, a metallic cable rack 9 according to Fig. 3 be. The example shown is a metal perforated metal cable tray with flanged upper edges.

The 4 and 5 show a schematic cross section of an embodiment of the flat cable 1 with two-layer core insulation on the cable rack 9 in the normal state, ie in non-fire ( Fig. 4 ) or in case of fire ( Fig. 5 ). The 4 and 5 together with associated description meet in an analogous manner to the single-layer embodiment of Fig. 1 and 2 to. The 4 and 5 thus illustrate the use of the embodiment of the Fig. 1 and 2 on an electrically conductive cable support before and after a fire.

At the in Fig. 4 exemplified two-layer core insulation, the core insulation of the live wires 7 (here the phase conductor and the neutral conductor) on an inner layer of the core insulation 3, which is made of ceramic in the event of fire, ie fireproof plastic, and an outer layer of the core insulation 10 made of non-fire-resistant plastic , The fire-resistant inner layer 3 is extruded directly onto the core conductor 2, while the non-fire-resistant outer layer 10 surrounds the inner layer 3.

This fire-resistant training of the core insulation can be provided with all wires 7, but can also be limited to the on live conductors (possibly including the neutral conductor). The latter is in the 4 and 5 by way of example, in which the protective conductor 7a (on the right in the picture on the right) has a uniform (ie single-layered) core insulation made of non-fire-resistant plastic 10.

The flat cable 1 lies in the event of non-fire flat on the cable tray 9, wherein the fire-resistant insulating layer 5 down, i. oriented to the bearing surface of the flat cable 1.

In the in Fig. 5 illustrated fire, ie after the substantially residue-free burning of the non-fire-resistant layer 10 of the wire insulation (or the entire Core insulation 10 of the protective conductor 7a), the intermediate sheath 4 and the outer sheath 6 remains of the fire-resistant (ceramizing) layer of the core insulation 3, the intermediate sheath 4, the fire-resistant insulating layer 5 and the outer sheath 6 only an insulating crust 3 'to each of the live conductor 2 and the insulating layer 5 left. The wires 7 'then lie with the insulating crust 3' directly on the fire-resistant insulating layer 5. The protective conductor 7a 'does not form such a crust; the conductor 2 of the protective conductor 7a 'therefore lies directly on the fire-resistant insulating layer 5.

For the insulation of the wires 7 'with each other, the insulating crusts 3' provide. The insulating crusts 3 'and, in addition, the insulating layer 5 ensure insulation from the metallic cable tray 9. As already mentioned, the fire-resistant insulating layer 5 extends with the width 28 (FIG. Fig. 2 ) at least below the entire surface in which the wires 7 ', 7a' of the flat cable 1 extend. In other words, the fire-resistant insulating layer 5 extends at least over the entire width of the flat cable 1, in the case of fire veins 7 ', 7a' rest.

The same applies in case of fire for the embodiment of Fig. 1 and 2 in the variant with single-layer wire insulation with the proviso that not only the inner layer of the wire insulation forms an insulating crust, but the entire thickness of the wire insulation, since they are mixed over their entire thickness with ceramizing additives.

The FIGS. 6A to C illustrate steps of an exemplary manufacturing method of the flat cable 1 for both embodiments of the Fig. 1 / 2 and Fig. 4/5 , The FIGS. 6A and 6C show a suitable extrusion device for this purpose in side view; Fig. 6B shows such in plan view. For the sake of simplicity, the manufacturing method is shown here with reference to a cable with only three wires 7.

First, the fire-resistant core insulation 3 or the fire-resistant inner layer 3 of the core insulation is sprayed onto the core conductor 2. Fig. 6 A shows the production of a single wire 7. The other required wires 7 are prepared accordingly. The core insulation 3 or the inner layer 3 of the core insulation is sprayed onto the core conductor 2 by extrusion of a plastics melt mixed with a ceramic additive in the event of fire directly. For this purpose, the core conductor 2, eg copper wire, is mechanically stretched by an unwinding drum 31 through an extruder 37, namely pulled centrally through a shaping extruder die 35. The extruder die 35 is circular and has a diameter which substantially corresponds to the outer diameter 21 of the core and the outer diameter of the inner layer 3, respectively. The amount of plastic melt extruded per unit time and the feed rate of the copper wire are matched to each other, so that the outer diameter of the sprayed core insulation substantially the desired value, namely the nozzle diameter (core outer diameter 21 and Outside diameter of the inner layer 3) corresponds. The plastic coating solidifies by cooling after exiting from the extruder die 35, and thus forms the ceramic insulation in the event of fire core insulation 3. The wire 7 is wound on a take-up drum 33. The said mechanical stress is achieved by means of the take-off and take-up reels 31 and 33, respectively.

In embodiments with two-layer core insulation ( 4 and 5 ), the outer layer of the core insulation 10 is extruded from non-fire-resistant plastic to the inner layer 3 in a further analog extrusion process.

Non-fire resistant cores 7a are prepared in an analogous manner in an extrusion process by extruding the core insulation 10 of non-fire resistant plastic directly onto the conductor 2.

Then takes place according to Fig. 6B the injection of the (eg not fire-resistant) intermediate sheath 4 on the wires 7 and 7a, here three wires 7. It takes place by extrusion of a plastic melt (containing, for example, no ceramizing additives) directly on the wires 7. For this purpose, the required number of wires 7 (here three wires 7) parallel to each other in a plane in that distance corresponding to the later distance in the produced flat cable 1 (distance 22 in Fig. 2 ), mechanically stretched from one unwinding drum 41, 41 ', 41 "by a further extruder 47, namely pulled centrally through a shaping extruder die 45. The extruder die 45 corresponds in shape essentially to the outer contour of the intermediate jacket 4 to be produced Intermediate vein intersecting, and the veins 7 completely embedding intermediate coat 4. The amount of extruded per unit time plastic melt and the feed rate of the wires 7 are in turn so matched to each other that the outer dimensions of the sprayed intermediate jacket 4th essentially correspond to the desired values, namely the nozzle dimensions or the thickness and width of the intermediate jacket 4. The plastic coating solidifies by cooling after exiting the extruder die 45, thus forming the intermediate sheath 4 on the wires. The resulting intermediate product 50 (intermediate casing 4 with the embedded wires 7) is wound onto a take-up drum 43. The said mechanical stress is achieved by means of the take-off and take-up drums 41, 41 ', 41 "and 43, respectively.

Finally, the spraying of the (eg fire-resistant) outer jacket 6 onto the intermediate product 50 and a fire-resistant insulating layer 5 is carried out. This is again carried out by extrusion of a plastic melt (containing, for example, no ceramizing additives) onto the intermediate product 50 and the fire-resistant insulating layer 5 Fig. 6C , For this purpose, the intermediate product 50 with the applied insulating layer 5 is mechanically stretched by a respective unwinding drum 51, 58 by a further extruder 57, namely pulled centrally through a shaping extruder die 55. In the illustrated embodiment, the fire-resistant insulating layer 5 is placed on one side only on the intermediate product 50. In other embodiments variants, the fire-resistant insulating layer 5 is placed on both sides of the intermediate product 50; this can be done, for example, by unwinding two fire-resistant insulating tapes from unwinding reels in the manner of the unwinding reel 58 shown, or by wrapping the intermediate product 50 with a fire-resistant insulating tape before this third extrusion process. The extruder nozzle 55 corresponds in shape essentially to the outer contour of the flat cable 1 to be produced. Thus, the intermediate jacket 4 including the fire-resistant insulating layer 5 embeds the outer jacket 6. The amount of plastic melt extruded per unit time and the feed rate of intermediate product 50 and insulating layer 5 are again matched to one another that the outer dimensions of the outer jacket 6 substantially corresponds to the desired values, namely the nozzle dimensions or the thickness and width of the flat cable 1. The plastic coating solidifies by cooling after exiting the extruder die 55, and thus forms the outer sheath 6. The resulting finished flat cable 1 is wound onto a take-up drum 53. The said mechanical stress is achieved by means of the take-off and Aufwickeltrommeln 51 and 53, respectively.

All publications cited in this specification are incorporated by reference.

Although certain products and processes in accordance with the teachings of the invention have been described herein, the scope of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention which fall within the scope of the appended claims, either literally or under the doctrine of equivalence.

Claims (18)

Flat cable (1) with short-circuit prevention in case of fire, even when laying on an electrically conductive support body, comprising: at least two cores (7, 7a) parallel to each other in a plane; wherein the cores (7, 7a) each have a core conductor (2) and a core insulation (3, 10) of annular cross-section, the core insulation (3, 10) being directly applied to the core conductor (2) in at least one of the cores (7). comprises extruded, in case of fire ceramising insulating material; an intermediate casing (4), which encloses the cores (7, 7a) as a whole and thereby encloses the core insulation (3, 10) directly on its outer side, wherein the intermediate casing (4) between each two cores (7, 7a) from a flat side of the Flat cable to the other flat side passes through; an outer sheath (6) surrounding the intermediate sheath (4) and defining the outer contour of the flat cable (1); at least one fire-resistant insulating layer (5), which is arranged on the outside of the intermediate casing (4) and lies between the intermediate casing (4) and the outer casing (6). Flat cable (1) according to claim 1, wherein the ceramic insulating material comprises plastic and at least one ceramizable additive. Flat cable (1) according to claim 2, wherein the ceramizable additive forms an insulating crust in case of fire when the plastic burns. Flat cable (1) according to one of claims 1 to 3, wherein in the at least one core (7) with insulating in the event of fire insulating the core insulation in its entire thickness (3) from the extruded, in the event of fire keramisierenden insulating material is made. A flat cable (1) according to any one of claims 1 to 3, wherein in the at least one core (7) with insulating material firing in the event of fire, an inner part (3) of the core insulation is produced from the extruded, in the event of fire ceramizing insulating material, while an outer part ( 10) of the core insulation is made of non-fire-resistant plastic. Flat cable (1) according to one of claims 1 to 5, in which - All wires (7) are equipped with in case of fire ceramizing insulating material; or - Only a portion of the wires (7) are equipped with fire-ceramising insulating, while in one or more wires (7a), which are intended to carry no voltage, the core insulation (10) is made of non-fire-resistant plastic, the Burns in case of fire. Flat cable (1) according to one of claims 1 to 6, wherein the intermediate casing (4) is made of non-fire-resistant plastic which burns in the event of fire without leaving an insulating crust or insulating layer. Flat cable (1) according to one of claims 1 to 7, wherein the intermediate casing (4) is extruded directly onto the outer side of the core insulation (3, 10). Flat cable (1) according to one of claims 1 to 8, wherein the distance between adjacent wires (7, 7a) through which the intermediate casing (4) engages, measured from outside to outside of the wire insulation (3, 10) at least the radius of the wires ( 7, 7a) corresponds. Flat cable (1) according to one of claims 1 to 7, wherein the at least one fire-resistant insulating layer (5) is arranged on both flat sides of the flat cable (1). Flat cable (1) according to one of claims 1 to 10, wherein the at least one fire-resistant insulating layer (5) is arranged only on one of the two flat sides of the flat cable (1). Flat cable (1) according to one of claims 1 to 11, wherein the outer sheath (6) of the flat cable (1) has a shape which has no 180 ° symmetry, so that thereby the flat side of the cable to which the at least one fire-resistant insulating layer (5) is arranged, can be seen from the outside. A flat cable (1) according to any one of claims 1 to 12, wherein the at least one fire-resistant insulating layer (5) comprises a refractory insulating mineral. A flat cable (1) according to any one of claims 1 to 13, wherein the at least one fire-resistant insulating layer (5) comprises silicate. A flat cable (1) according to any one of claims 1 to 14, wherein the at least one fire-resistant insulating layer (5) is a mica layer. Use of a flat cable (1) according to one of claims 1 to 15, such that the flat cable (1) is laid on an electrically conductive support body, wherein the flat cable (1) is oriented such that between the wires (7, 7a) and the support body, the at least one fire-resistant insulating layer (5) comes to rest. Method for producing a flat cable (1) with short-circuit prevention in case of fire, even when laying on an electrically conductive cable support, comprising: Manufacture of cores (7) with a directly on a core conductor (2) arranged in cross-section core insulation (3, 10), wherein the production of the core insulation (3, 10) encapsulating a core conductor (2) with a ceramizing in case of fire insulating material comprising an extruder (37); Application of an intermediate sheath (4) on a plurality of cores (7, 7a), of which at least one core (7) is equipped with the insulating material ceramized in the event of fire, wherein the cores (7, 7a) run parallel to each other in a plane, wherein the intermediate sheath (4) encloses the cores (7, 7a) as a whole and thereby encloses the core insulation (3, 10) directly on the outside thereof, and in each case passes through between two cores (7, 7a) from one flat side of the flat cable to the other flat side; Applying at least one fire-resistant insulating layer (5) on the outside of the intermediate jacket (4); Applying an outer sheath (6) on the intermediate sheath (4) together with fire-resistant insulating layer (5), which defines the outer contour of the flat cable (1). Method for producing a flat cable (1) according to Claim 17, with further features according to one of Claims 1 to 15.

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