EP3054457B1 - Cable for use in fuel area - Google Patents

Description

The invention relates to a cable which is suitable for use in the fuel sector or in areas in which fuels can occur.

In practice, electrical or optical cables and wires should withstand various influences, in particular mechanical and chemical influences. Good fire resistance of the cables is also required for various applications in order to maintain functionality in the event of a fire. The properties of the individual functional units of the cable, the electrical or optical conductors, the conductor insulation, any shielding and the cable sheath must therefore be designed in accordance with the requirements.

There are high demands on the mechanical and chemical resistance particularly when using cables in the offshore area, in oil and gas drilling or in shipbuilding and seafaring. In this area of application, cables are often routed through zones in which fuels or residues of fuels are present. There are often fuel residues in dirt residues, in the soil and in particular in materials that are extracted from the soil. Easily combustible oil components are usually present in the drilling mud that accumulates at a drilling site.

Cables that are intended for these areas of application must have a high resistance to various chemical substances, including sea water, hydrocarbons, oils, drilling fluids and mud, especially drilling mud.

Cable requirements are specified by national and international standards, with the NEK (Norsk Elektroteknisk Committee) 606 standard usually being used.

• "Bohrschlamm" bezeichnet ein Fluid mit komplexer Mixtur welches im Zusammenhang mit Öl- und/oder Gasbohrungen sowie sonstigen Erdbohrungen produziert und/oder angewendet wird.
• "Schlammbeständig" bezeichnet die Beständigkeit gegenüber Bohrschlamm gemäss NEK 606:2004.

The following definitions are used for the following explanations:

• "Drilling mud" means a fluid with a complex mixture which is produced and / or used in connection with oil and / or gas drilling and other earth drilling.
• "Sludge resistant" refers to the resistance to drilling mud in accordance with NEK 606: 2004.

Due to the possible flammability of drilling mud and the like, it is necessary that the cables are prepared for the event of fire and provided with a flame-retardant protective cover. A corresponding cable is from the EP2115093B1 known.

Fires in these areas of application often have serious consequences for people, the environment and materials, which is why it would be desirable to improve technical equipment and the cables used so that such accidents can be avoided or the effects of incidents reduced.

The present invention is based on the object of providing a further improved cable which can be used in areas in which fuels are present or can occur.

In particular, a cable should be created with properties that reduce the risk of fire and explosions occurring in particular in these hazardous areas.

The cable should also be resistant to sludge.

Furthermore, the cable should have good temperature resistance and be usable in a wide temperature range at least between -40 ° C and + 80 ° C.

This object is achieved with a cable which has the features specified in claim 1. Advantageous embodiments of the invention are specified in further claims.

The cable, which is intended for use in fuel areas, comprises at least one electrical and / or at least one optical conductor, an insulation layer which encloses the at least one conductor and an outer jacket which encloses the aforementioned components.

According to the invention, the outer jacket is made from a polymer mixture which contains an antistatic additive.

Laboratory studies have shown that static discharges can occur on the outer surface of the cable sheath (also called outer sheath), which can contribute to the ignition of a fuel, in particular a gaseous fuel, which is present in a sufficiently high concentration. It was found that static discharges can occur between the cable sheath and a third body as well as between differently charged outer surfaces of different sections of the cable sheath, e.g. if different turns of the cable lie on top of each other.

By doping the outer sheath with the antistatic additive, this source of danger is excluded and prevents static discharges and thus caused Sparks appear on the surface of the cable jacket, causing fires or explosions.

In a preferred embodiment, the antistatic additive is added to the jacket material in such an amount that a surface resistance of the outer jacket results which is less than 10 ⁹ ohms and greater than 10 ⁴ ohms. The antistatic additive is particularly preferably added to the jacket material in such an amount that the surface resistance of the outer jacket is less than 10 ⁸ ohms and greater than 10 ⁷ ohms. This suitable choice of admixing the objective results in an outer jacket which on the one hand has the desired insulation properties and on the other hand does not show any static discharges.

In a further preferred embodiment, the outer jacket is constructed from a plurality of, preferably at least two, layers. The outer casing preferably comprises an upper layer which is made of a material to which the antistatic additive is mixed in such a way that a surface resistance of the outer casing results which is between 10 ⁹ ohms and 10 ⁴ ohms, preferably between 10 ⁸ ohms and 10 ⁷ ohms.

The at least one underlayer, on the other hand, is made from another material which is optimized with regard to the required mechanical, chemical or electrical properties of the cable. Compared to a single-layer outer jacket, various properties can be optimized using this multi-layer cable jacket.

The material of the underlayer is preferably chosen such that the cable complies with the IEC standards regarding flame retardancy 60332-1 and / or 60332-3 or an analog test protocol.

The outer jacket or the top layer are preferably produced by means of an extrusion process.

The individual conductors which are contained in the cable can each be enclosed individually or in groups by a layer which serves to shield against electromagnetic radiation.

In a further preferred embodiment, the outer sheath or, if the cable sheath has a multilayer structure, at least the upper layer of the cable sheath is designed to be sludge-resistant in accordance with NEK 606: 2009.

In a preferred embodiment, the outer jacket is made of a polymer-based material, preferably a thermoplastic polymer, more preferably a thermoplastic polyurethane.

According to the invention, the proportion by weight of the antistatic additive in the polymer mixture for the material of the outer jacket is selected such that a surface resistance of the outer jacket results which is between 10 ⁹ ohms and 10 ⁴ ohms, preferably between 10 ⁸ ohms and 10 ⁷ ohms. The proportion by weight of the antistatic additive is preferably 0.1% to 10%, more preferably 0.1% to 2%.

• Fig. 1 einen Querschnitt durch ein erfindungsgemässes Kabel;
• Fig. 2 einen Querschnitt durch eine weitere Ausführungsform eines erfindungsgemässen Kabels;

The invention is explained in more detail below with reference to drawings. It shows:

• Fig. 1 a cross section through an inventive cable;
• Fig. 2 a cross section through a further embodiment of a cable according to the invention;

Fig. 1 shows a cross section of a cable 10 according to the invention. An electrical conductor 1 is surrounded by a uniform insulation layer 2. An outer jacket 3 is applied to the insulation layer 2. Alternatively, an optical conductor 1 can be used instead of the electrical conductor 1. Likewise, further polymer-based layers or braided shields can be arranged between the insulation layer 2 and the outer jacket 3, which serve for shielding.

Fig. 2 shows a cross section of a cable 10 according to the invention in a further preferred embodiment. Several electrical or optical conductors 1 are each surrounded by an insulation layer 2. The insulated conductors 1 are interconnected by an inner jacket 4 or worshiped in an inner jacket 4. An optional shield 5 is preferably arranged between the inner jacket 4 and the lower layer of the outer jacket 3a. The outer sheath of the cable 10 consists of an outer top layer 3 and a bottom layer 3a. The lower layer 3a and the upper layer 3 of the outer jacket can also be implemented in a single layer. The number of conductors 1 can be selected as required.

The invention is explained in more detail below on the basis of exemplary embodiments:

Examples 1 to 6 and Comparative Examples 7 and 8

The material for the outer jacket of a cable according to the invention was manufactured in accordance with Table 1. The compounding of the base material and the antistatic or the antistatic additive was carried out in each case using the dry blend process. The Elastollan® materials were purchased from BASF, the antistatic agent 110346 NP TPU AS Masterbatch from PolyOne.

Table 2 shows measured values for relevant material parameters for Examples 1-8. Examples 1-6 according to the invention show good mechanical values in comparison to comparative examples 7 and 8. The addition of the antistatic additive only slightly reduces the tensile strength and elongation at break.

Table 3 shows the surface resistance of Examples 1-8 after the materials were subjected to aging in salt water in accordance with UL 1309. The surface resistance is reduced by storage in salt water, but examples 1-6 according to the invention are in the desired resistance range between n * 10 ⁹ ohms and m * 10 ⁷ ohms both before and after storage in salt water.

Table 4 shows the tensile strength and elongation at break of Examples 1-8 after the materials have been aged in air for 7 days at 110 ° C, in accordance with EN 60811-1-2 Section 8.1.3.1. The changes are in the range permitted by the standard.

Table 5 shows the tensile strength and the elongation at break of Examples 1-8 after the materials had been aged for 7 days at 100 ° C. in the reference oil IRM 903, in accordance with NEK 606: 2009. The changes are in the range permitted by the standard. <b> Table 1: </b> Example No. Base material Antistatic Weight percent antistatic 1 (according to the invention) Elastollan® 1198 A 10 FHF Elastollan® Konz V2925 0.5% 2 (according to the invention) Elastollan® 1198 A 10 FHF Elastollan® Konz V2925 1.0% 3 (according to the invention) Elastollan® 1198 A 10 FHF Elastollan® Konz V2925 3.0% 4 (according to the invention) Elastollan® 1198 A 10 FHF 110346 NP TPU AS masterbatch 2.0% 5 (according to the invention) Elastollan® 1198 A 10 FHF 110346 NP TPU AS masterbatch 10.0% 6 (according to the invention) Elastollan® 1185 A Elastollan® Konz V2925 1.0% 7 (state of the art) Elastollan® 1198 A 10 FHF - 0 8 (state of the art) Elastollan® 1185 A - 0 No. Surface resistance [Ω] according to IEC 60093 Tensile strength [MPa] according to DIN EN ISO 527-2 Elongation at break [%] according to DIN EN ISO 527-2 1 9.5 x 10 ⁷ 21.16 490.45 2nd 3.8 x 10 ⁷ 18.22 448.54 3rd 1.6 x 10 ⁷ 15.38 421.85 4th 8.0 x 10 ⁷ 20.91 492.14 5 1.1 x 10 ⁷ 14.13 421.21 6 1.6 x 10 ⁷ April 43 610.45 7 7.0 x 10 ⁹ 24.41 500.92 8th 3.4 x 10 ⁹ 45.19 610.04 No. Surface resistance [Ω] according to IEC 60093 1 4.8 x 10 ⁷ 2nd 2.0 x 10 ⁷ 3rd 7.7 x 10 ⁷ 4th 6.6 x 10 ⁷ 5 1.5 x 10 ⁷ 6 1.1 x 10 ⁷ 7 3.1 x 10 ⁸ 8th 4.7 x 10 ⁸ No. Tensile strength [MPa] according to DIN EN ISO 527-2 Elongation at break [%] according to DIN EN ISO 527-2 1 20.94 467.64 2nd 18.22 433.82 3rd 15.38 389.31 4th 20.91 469.77 5 13.24 410.51 6 37.44 595.03 7 11/22 471.84 8th 39.41 593.49 No. Tensile strength [MPa] according to DIN EN ISO 527-2 Elongation at break [%] according to DIN EN ISO 527-2 1 20.39 455.15 2nd 18.42 446.04 3rd 15.90 434.91 4th 20.28 465.54 5 15.75 461.13 6 41.45 620.09 7 December 23 463.19 8th 48.59 608.78

Reference list

1

electrical conductor

2nd

Insulation layer

3rd

Outer jacket

3a

Lower layer of the outer jacket

4th

Inner jacket

5

shielding

10th

electric wire

Claims (7)

1. Cable (10) for use in the fuel sector, with

   - at least one electrical and / or at least one optical conductor (1);

   - An insulation layer (2) which surrounds the conductor (1) ;

   - An outer jacket (3), which encloses the aforementioned components and which is made from a polymer mixture that is based on a thermoplastic polymer and that comprises an antistatic additive ,
   characterized in that the outer jacket (3) comprises at least one lower layer (3a) and an upper layer (3b), the upper layer (3b) being mud-resistant according to norm NEK 606:2009 and comprising the antistatic additive and that the thermoplastic polymer is a thermoplastic polyurethane.
2. Cable (10) according to claim 1, characterized in that the surface resistance of the outer jacket (3) is less than 10⁹ Ohm and more than 10⁴ Ohm.
3. Cable (10) according to claim 2, characterized in that the surface resistance of the outer jacket (3) is in the range between 10⁷ Ohm and 10⁸ Ohm.
4. Cable (10) according to one of claims 1 to 3, characterized in that the at least one lower layer (3a) is designed to be flame-retardant or highly flame-retardant in accordance with one of the standards IEC 60332-1 and IEC 60332-3.
5. Cable (10) according to one of claims 1 to 4, characterized in that at least two conductors (1) are provided, which are surrounded by a shield (5).
6. Cable (10) according to one of claims 1 to 5, characterized in that the outer jacket (3) or the top layer (3b) is an extrusion product.
7. Cable (10) according to one of claims 1 to 6, characterized in that the proportion by weight of the antistatic additive in the polymer mixture is between 0.1% and 10%, preferably between 0.1% and 2%.

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