WO1999048112A1

WO1999048112A1 - Cable

Info

Publication number: WO1999048112A1
Application number: PCT/CZ1998/000041
Authority: WO
Inventors: Pavel Kupilik
Original assignee: Pavel Kupilik
Priority date: 1998-03-16
Filing date: 1998-10-16
Publication date: 1999-09-23
Also published as: SK97498A3; CZ80198A3; CZ285783B6; SK282879B6

Abstract

The cable, which has increased resistivity to fire progagation and/or the cable being able to operate during fire, consisting of a core (7), formed by at least one conductor (3), where the outer surface of said core (7) can be wrapped around by a foil (5), said cable core (7) being envelopped by a sheath (6). The space inside the sheath (6), envelopping the core (7) with at least one conductor (3) being formed by a central portion (1) and insulation (2), is filled with filling composition (4) in a form of a granulated material composed of 60 to 62 mass per cent of SiO2, 29 to 31 mass per cent of MgO, 1.25 mass per cent of A12O3, at most 1.0 mass per cent of Fe2O3 and of trace elements such as Zn, Ti, Ba and Zr in a form of oxides, the amount of which is at most 1 mass per cent.

Description

Cable

Field of technics

The invention relates to a cable which has increased resistance to fire propagation or a cable which is able to function during fire.

State of the art

The presently produced fire retarding and fireproof cables make use of plastifying thermoplastic compositions containing specific amount of complementing fire-retarding essences as starting material (e.g. magnesium and calcium or aluminium hydroxides, respectively) above all which do not generate dangerous products when burning. For the time being, higher price of these raw materials does not enable the wide-scale employing of halogenless and fire-retarding cables in common conditions even at the very cost of greater risk of damage due to fire rise in strucftires.

The electric conductors insulation as based on ceramics utilization is being applied in electric heat supplies and leads with slided beads to heating bodies above all .Coaxial cable internal central portions are being insulated in the same way.

Due to small flexibility of condutors made in this way with unsufficient insulation homoge- nity, these applications are progressively less used with respect to great amount of work and some limitations in proper production, too.

Essence of llie invention

The above mentioned disadvantages are suppressed by a cable which is more resistant to fire propagation and which is able lo function in lire. The cable consists of a core formed of al least one conductor where the outer core surface can be wrapped round by a foil, (he cable core being envelopped by a sheath.

The essence of the invention is rooted in that the space inside the sheath, in which there is a core consisting of at least one conductor formed by a central portion and an insulation, is filled by filling composition consisting of granulated material composed of 60 to 62 mass per cent of Si0₇, 29 to 31 mass per cent of MgO, at most 1.25 mass per cent of AI2O3, at most 1.0 mass per cent of Fe2U3 as well as of trace elements Zn, Ti, Ba and Zr in a form of oxides in an amount of at most 1 mass per cent. In an advantageous design the cable core consists of at least one communication cable component and on the conductor outer surface, the non-drying and non-aggressive solution of the silicon oil type is deposited.

Fire-retarding and fireproof cables, produced presently by adding and utilizing the application of granulated filling composition according to the invention, will further improve the cable features and simultaneously cut off the total cable price.

In case of fire penetrating into the cable system, the design, according to the invention, reduces the optical density of smoke generated during cable burning. By this, the design makes easier the fire localization and improves and accelerates the fire liquidation as well.

Another advantage stands for retarding the time instant in which the final cable destruction and function capability loss occur when the cable is exposed to fire.

Survey of figures on the drawings

The invention is explained, in more detail, by means of drawings where at Figs I to 4 (he cable is presented in cross section and in elevation.

Examples on invention realization Example 1

The copper central portion 1 of the conductor 3 of the one-conductor cable is provided with an uninterrupted insulation 2 of the conductor 3, said insulation consisting of plastic insulating composition.

The filling composition 4, in a form of granules composed of 62 mass per cent of SiCb, 29 mass per cent of MgO, 1.25 mass per cent of AI2O3, 1.0 mass per cent of Fe2θ3 and trace elements as Zn, Ti, Ba and Zr in a form of oxides in an amount of 1 mass per cent, the rest being impurities, has been deposited on the conductor 3 over its total circumference. The cable core 7, set up in (his way, is provided with the cable sheath 6.

Example 2

In the multiconductor cable, consisting of conductive central portions 1 insulated by means of a continuous insulation 2, all free spaces among individual conductors 3 are filled and on the whole circumference of these conductors 3, spliced in rope, a filling composition has been deposited in a form of granules consisting of 60 mass per cent of SiCb, 31 mass per cent of

MgO, 1.25 mass per cent of AI2O , 1.0 mass per cent of Fe2U3 and trace elements as Zn, Ti,

Ba and Zr,in a form of oxides in an amount of 1 mass per cent. The rest consists of impurities.

- 2 - The cable core 7,consrructed in this way, is wrapped round by a foil 5 which reinforces the whole set of cable core 7 and, simultaneously, prevents the dropping out of the filling composition 4 in granulated form until the technologic process of making the sheat 6, in which the whole cable core 7 is enclosed, has been completed.

Example 3

A multiconductor cable, composed of conducting central portions J_, provided with wrapping round by a glass-mica layer 8 and insulated by uninterrupted insulation 2, has a cable conductor 3, being spliced in rope in positions 9, all free spaces of the cable core 7 being filled by filling composition 4 in a granulated form. In this case the composition consists of 61 mass per cent of Siθ2, 30 mass per cent of MgO, 0.75 mass per cent of Abθ3, 0.75 mass per cent of Fe2U3 and trace elements Zn, Ti, Ba and Zr, always in a fonn of oxides, in an amount of 0.75 mass per cent. The rest consists of impurities.

The filling composition 4 is being deposited upon the last position 9 of spliced conductors 3 in the cable core 7 by drawing through along with pouring the filling composition 4, in granulated fonn, into the position 9, of conductors 3, moistered by silicon oil. The cable core 7 is provided with cable sheath 6.

Example 4

The communication cable is set up of components _K) formed by stranding of at lest two conductors 3 consisting of a central portion _]_ and of the insulation 2.

The cable components J_0 are spliced in rope and, in free spaces and especially on the circumference, are provided with filling composition 4 in a form of granulated material consisting of 62 mass per cent of SiC , 30 mass per cent of MgO, 1.0 mass per cent of AI2O , 0 90 mass per cent of Fe2θ and trace elements as Zn, Ti, Ba and Zr, in a fonn of oxides, alwys in an amount of 0.5 mass per cent, the rest being impurities.

The filling composition 4 is prevenled from dropping out before and during following cable core 7 processing, by the foil 5_ which enveloppes the cable core 7. The cable core 7 is provided with a cable shieth 6.

By making use of the filling composition 4, in a fonn of granulated material, the original features are ensured in cables in nonnal operation. In case of exposition to fire, the filling composition 4 is gradually sintered along with making further burning impossible and with fixing the position of the central portion i in the cable core 7 and with fonning the sintered insulation of the central portion 1 after burning down of organic parts of the mixture of structural cable components.

- 3 - During exposition to fire, the filling composition 4 does not liberate any dangerous elements, and from temperatures about 600°C, individual phases of its gradual sintering start to take place.

Utilization in industry

Making use of this design is given a reason especially in wide-scale cable application in structures in which further damage, due to fire propagation along the cabling of electric wiring, can be supposed in case of fire.

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Claims

PATENT CLAIMS

1. The cable which has increased resistivity to fire propagation and/or the cable being able to operate during fire, consisting of a core (7), which is formed by at least one conductor (3), where the outer surface of said core (7) can be wrapped around by a foil (5), said cable core (7) being envelopped by a sheath (6), characterized in that, the space inside said sheath (6), envelopping said core (7) with at least one conductor (3), fanned by a central portion (1) and insulation (2), is filled with filling composition (4) in the fonn of a granulated material which is composed of 60 to 62 mass per cent of Si╬╕2, 29 to 31 mass per cent of

MgO, at most 1.25 mass per cent of AI2O , at most 1.0 mass per cent of Fe₇0 and of trace elements as Zn, Ti, Ba and Zr in a fonn of oxides the amount of which is at most 1 mass per cent.

2. The cable of Claim 1, characterized in that, the core (7) is formed by at least one component (10) of the communication cable.

3. The cable of Claims 1 and 2, characterized in that, the non-drying and non- aggressive solution of a type of silicon oil is deposited on the outer surface of the conductor (3).

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