DE3012321A1 - TWO OR MULTIPLE CABLE - Google Patents

Abstract

The conductor core (1) of each wire is in each case surrounded by a pore-free insulating layer (2). All the wires are stranded together with filler material (3). An enveloping foil winding (4) produces a round, compact conductor bundle. The screening braid (5) which is wound around the conductor bundle also, for its part, has a metal foil (6) wound around it. A pore-free protective sheath (8) is extruded around the screen (6) after insertion of a tearing wire (7). The triple insulation results in good resistance to external physical and chemical influences. The metal strip (6) which is wound around the screening braid (5) leads to advantageous closed screening with respect to electrical and magnetic fields and helps to dissipate local heat effects, in addition to which the sheath material cannot anchor itself between the wires of the screening braid, which has an advantageous effect in the event of the cable being subjected to alternating bending stress. <IMAGE>

Description

Two-core or multi-core cable

The present invention relates to a two or more conductor cable according to the preamble of claim 1.

For thermoelectric measuring devices are in particular related with thermocouples compensating conductor cable for temperature measurement as a connection line used between thermocouple, reference junction and measuring device. Lately is also the temperature measurement with the inclusion of process computers for control or used for regulation. A measurement signal transmission is therefore always higher Requirements regarding decoupling, freedom from interference and other external influences. Mechanical and physical environmental influences, along with chemically aggressive compounds, often act from the outside on the cable. In addition, the demand for thinner cables that use the occurring harmful influences and due to the trends towards Compact design may take up less space.

Particularly high demands are placed on signal conductor cables or

on cables for measuring, controlling and regulating (called MSR cables) for example placed in power stations, where strong electric and magnetic fields produce high resistance Can interfere with measuring circuits. The known conductors of this type usually have insulation made of plastomers and elastomers or impregnated glass fiber. But these cables are Sensitive to moisture, corrosion and lubricants, some of them do not hold up very high temperatures and take up a lot of space, the latter especially, if the insulation is for a test voltage of 2000 V in accordance with the applicable test regulations must be made relatively thick-walled.

The object of the invention is therefore to construct a heat-resistant cable with high abrasion and notch resistance as well as high immunity to interference, that takes up little space, works for a long time at temperatures of up to around 4000 C remains, offers high security in the event of fire, oil and chemical resistant and not is hygroscopic and so guarantees the proper transmission of signals and Provides tension.

According to the invention, this object is achieved in a two- or multi-conductor cable according to the characterizing part of claim 1 fulfilled.

An exemplary embodiment of the invention is described below with reference to FIG Drawing explained. Show it: Fig. 1 is a cross-sectional view through a cable according to the invention and FIG. 2 a perspective view of the cable according to Fig. 1 with partially cut and partially twisted wraps.

In the cable shown are two conductors 1 made of copper, aluminum or other suitable metal combinations available as twisted stranded conductors. Each individual conductor 1 is provided with an insulation 2 made of a fluorocarbon, which enables a pore-free layer with the smallest possible wall thickness and a high breakdown voltage guaranteed.

Such a fluorocarbon is, for example, FEP, "Tefzel" etc.

This also leads to a good resistance to water and Oil, phosphate esters etc. also at higher temperatures, but also too good mechanical ones Properties at very low temperatures. By briefly twisting the two insulated conductors 1 are known to be low interference from external fields held. The filler material 3, e.g. made of glass fibers, is included in the stranding, results in an approximately circular cable cross-section.

One wrapped around this bundle of cores 1 and filler material 3 Tape 4 made of a polyimide film, which is also used as a composite film educated can be, leads to a smooth outer surface and at the same time forms another Heat shield.

This insulated wire bundle is coaxially wrapped with a braided shield 5. This braided shield 5 has various advantages, one of which is the shielding effect against electric and magnetic fields and the rapid dissipation of heat in a locally concentrated strong warming are particularly to be emphasized.

If, in addition, care is taken that the stranded bundles of the wires 1 and the stranded shield 5 have the same cross-sections, this brings advantages in the Connection technology by using only one size of terminal or cable lug got to. So that this advantage is retained even with smaller diameters of the conductor cores can be, a wrapping 6 with a metal foil is on the braided shield 5, e.g. made of copper, so that the braided shielding, which is complex in the manufacturing process be unnecessary. This improves both the shielding and the dissipation and achieved the advantageous embodiment with the same diameters, thereby substantial Assembly costs are saved.

A tear wire is placed over this now practically circular strand of wires 7 is also inserted when applying the jacket 8, which enables effortless removal of the Jacket at the connection points. The jacket 8 again consists of one selected, extrudable fluorocarbon to achieve the same advantageous physical and chemical properties as they are already used for core insulation be cited.

It has been shown that the influence of electrical and magnetic Interference fields is minimized by this structure.

The metal foil 6 forms an outwardly closed one over the braid 5 Surface and also has the advantage that the jacket material is not between the individual stranded wires can penetrate. Thus, it is also easy to remove the sheath insulation guaranteed.

For the core insulation is also to achieve the same, through the test specifications prescribed dielectric strength compared to conventional ones Insulation materials about half the wall thickness of the insulation are sufficient.

Claims (4)

Claims ½) Two- or multi-conductor cables for the transmission of electrical Signals for measured values, control commands or control processes with short-stranded and shielded, electrically insulated conductors under a heat-resistant outer jacket, characterized by individually insulated conductors (1), which together with filler material (3) are appropriately stranded short-looped to form a rounded cable body a first wrapping (4) of the cable body with polyimide tape, through a second Wrapping (5) with a shield conductor function, by a third wrapping (6) with a conductive metal foil, through a tear wire (7) and through one made of a fluorocarbon existing protective sheath (8). 2. Cable according to claim 1, characterized in that the conductor (1) and the second wrapping (5) each consist of stranded wire, and that all strand bundles have at least approximately the same cross-sections. 3. Cable according to claim 1, characterized in that the third Wrapping (6) is made from a copper, aluminum or mu-metal tape, - serves as a shield and with the second, serves as a shield conductor connection Wrapping (5) is galvanically connected. 4. Cable according to one of claims 1 to 3, characterized in that that the insulation (2) of the conductor (1) also consists of a fluorocarbon, so that to achieve the same dielectric strength compared to other insulating materials about half the wall thickness of the insulation is sufficient.