Claims:
STATEMENT OF CLAIMS

We claim:

1. A composite cable comprising:
a circular central strength member (10);
one or more optical fiber sub groups (9) and one or more insulated metallic conductor sub groups (8) stranded around said circular strength member (10), wherein said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8) are located near an outer periphery of the composite cable;
a sheath enveloping said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8),
whereby said composite cable is powered by one of Direct Current (D.C.) power supply and Alternating Current (A.C.) power supply.

2. The composite cable as claimed in claim 1 further comprising a jelly, wherein said jelly is filled between one or more optical fiber sub groups (9) and one or more insulated metallic conductor sub groups (8).

3. The composite cable as claimed in claim 1 further comprising a layer of tape (7).

4. The composite cable as claimed in claim 1, wherein said one or more insulated metallic conductor sub groups (8) has one or more conductors, wherein each conductor of said one or more conductors is colored.

5. The composite cable as claimed in claim 1, wherein said one or more insulated metallic conductor sub groups (8) are colored.

6. The composite cable as claimed in claim 1, wherein said one or more optical fiber sub groups (9) comprises one or more buffer tubes, wherein each buffer tube of said one or more buffer tubes have one or more optical fibers, wherein said one or more buffer tubes has jelly.

7. The composite cable as claimed in claim 1 further comprising a jacket, wherein said jacket is defined by an inner periphery and an outer periphery, wherein said jacket has one or more ripcords (11) placed at said inner periphery of said jacket.

8. The composite cable as claimed in claim 1, wherein an operational temperature range is -90 to +990 degree Celsius.

9. The composite cable as claimed in claim 1 has an operating voltage of 48V DC.

10. The composite cable as claimed in claim 1 further comprising a metallic shield layer.

11. The composite cable as claimed in claim 1 is a flame retardant cable.

12. A composite cable comprising:
a circular central strength member (10), wherein said circular strength member (10) is a non-metallic anti-buckling fiber reinforce plastic;
one or more optical fiber sub groups (9) and one or more insulated metallic conductor sub groups (8) stranded around said circular strength member (10), wherein said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8) are located near an outer periphery of the composite cable, wherein each optical fiber sub group of said one or more optical fiber sub groups (9) have one or more colored fibers;
a sheath enveloping said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8).

13. The composite cable as claimed in claim 12 further comprising a jelly, wherein said jelly is filled between one or more optical fiber sub groups (9) and one or more insulated metallic conductor sub groups (8).

14. The composite cable as claimed in claim 12 further comprising a layer of tape (7).

15. The composite cable as claimed in claim 12, wherein said one or more insulated metallic conductor sub groups (8) has one or more conductors, wherein each conductor of said one or more conductors is colored.

16. The composite cable as claimed in claim 12, wherein said one or more insulated metallic conductor sub groups (8) are colored.

17. The composite cable as claimed in claim 12, wherein said one or more optical fiber sub groups (9) comprises one or more buffer tubes, wherein each buffer tube of said one or more buffer tubes have one or more optical fibers, wherein said one or more buffer tubes has jelly.

18. The composite cable as claimed in claim 12, wherein the composite cable has a permanent bending radius of 20D.

19. The composite cable as claimed in claimed 12 is suitable for underground installation.

20. The composite cable as claimed in claim 12 further comprising a jacket, wherein said jacket is made of one or a high density poly-ethylene (HDPE), a medium density poly-ethylene (MDPE), PVC, LSZH, thermoplastics and nylon.

21. A composite cable comprising:
a circular central strength member (10);
one or more optical fiber sub groups (9) and one or more metallic conductor sub groups (8) stranded around said circular strength member (10), wherein said one or more optical fiber sub groups (9) has one or more gel filled buffer tubes, wherein each of said one or more gel filled buffer tubes has one or more optical fibers, wherein said one or more metallic conductor sub groups (8) has one or more insulated copper conductors, wherein said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8) are located near an outer periphery of the composite cable;
a layer of tape (7) enveloping said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8); and
a sheath enveloping said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8).

22. The composite cable as claimed in claim 21 further comprising a jelly, wherein said jelly is filled between one or more optical fiber sub groups (9) and one or more insulated metallic conductor sub groups (8).

23. The composite cable as claimed in claim 21 further comprising a layer of tape (7).

24. The composite cable as claimed in claim 21, wherein said one or more insulated metallic conductor sub groups (8) has one or more conductors, wherein each conductor of said one or more conductors is colored.

25. The composite cable as claimed in claim 21, wherein said one or more insulated metallic conductor sub groups (8) are colored.

26. The composite cable as claimed in claim 21, wherein said one or more optical fiber sub groups (9) comprises one or more buffer tubes, wherein each buffer tube of said one or more buffer tubes have one or more optical fibers, wherein said one or more buffer tubes has jelly.

27. The composite cable as claimed in claim 21, wherein said composite cable has a permanent bending radius of 20D.

28. The composite cable as claimed in claim 21, wherein said composite has a weight in a range of 90-370 kg/km.

29. The composite cable as claimed in claim 21, wherein said composite cable has a nominal diameter in a range of 9 mm to 31.56 mm.

30. The composite cable as claimed in claim 21 further comprising a jacket, wherein said jacket is defined by an inner periphery and an outer periphery, wherein said jacket has one or more ripcords (11) placed at said inner periphery of said jacket.

31. A composite cable comprising:
a circular central strength member (10), wherein said circular strength member (10) is an up coated non-metallic fiber reinforced plastic;
one or more optical fiber sub groups (9) and one or more metallic conductor sub groups (8) stranded around said circular strength member (10), wherein said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8) are located near an outer periphery of the composite cable;
a sheath enveloping said one or more optical fiber sub groups (9) and said one or more insulated metallic conductor sub groups (8),
whereby said composite cable has a kink resistance of 20D.

32. The composite cable as claimed in claim 31 further comprising a jelly, wherein said jelly is filled between one or more optical fiber sub groups (9) and one or more insulated metallic conductor sub groups (8).

33. The composite cable as claimed in claim 31 further comprising a layer of tape (7).

34. The composite cable as claimed in claim 31, wherein said one or more insulated metallic conductor sub groups (8) has one or more conductors, wherein each conductor of said one or more conductors is colored.

35. The composite cable as claimed in claim 31, wherein said one or more insulated metallic conductor sub groups (8) are colored.

36. The composite cable as claimed in claim 31, wherein said one or more optical fiber sub groups (9) comprises one or more buffer tubes, wherein each buffer tube of said one or more buffer tubes have one or more optical fibers, wherein said one or more buffer tubes has jelly.

37. The composite cable as claimed in claim 31 further comprising a jacket, wherein said jacket is made of one or a high density poly-ethylene (HDPE), a medium density poly-ethylene (MDPE), PVC, LSZH, thermoplastics and nylon.

38. The composite cable as claimed in claim 31 further comprising a metallic shield layer.

39. The composite cable as claimed in claim 31 is rodent proof.

40. The composite cable as claimed in claim 31, wherein said composite cable has an operating temperature range of -90 to 990 degree Celsius.

41. The composite cable as claimed in claim 31, wherein said composite cable has an outer diameter of 9- 61 mm.

42. The composite cable as claimed in claim 31, wherein said composite cable has a crush resistance of 1900-5100 N, 600 sec.

43. The composite cable as claimed in claim 31, wherein said composite cable has a tensile strength 3000-7000 N.

Dated: 5th Day of February, 2019 Signature
Arun Kishore Narasani. Patent Agent.
IN/PA/1049
, Description:CROSS-REFERENCE OF RELATED APPLICATION
This application is a patent-of-addition of Indian application Ser. No. 1913/MUM/2006, filed on Nov. 20, 2006, the disclosures of which are hereby incorporated by reference in their entirety.
FIELD OF INVENTION

This invention relates to an optical fibre / metallic conductor composite cable.
More particularly this invention relates to an optical fibre / metallic conductor composite cable in which optical fibres for optic signal transmission and quads of copper conductors for signal transmission are used to achieve better and optimized optic as well as communication transmission of signals with screening effect to nullify the electro magnetic and electrostatic interference.

BACKGROUND OF THE INVENTION
An optical fibre / metallic conductor composite cable is known in the prior art such as US Pat No. 5268971 which comprises a cable core with optical fiber subgroup and an insulated metallic conductor subgroup. The optical fiber subgroup can be a loose tube construction, a slotted core construction, a unitube/monotube construction or a tight buffer tube construction. The individual insulated wires of the insulated metallic conductor sub group extend longitudinally within the composite cable. Preferably, the optical fiber subgroup is on the outer periphery of the cable core to provide easy accessibility, but it can be centrally located.

The cables for the transmission of information having both optical fiber and metallic conductor components, thereby reducing the costs involved in removing the existing copper cables and installing optical fiber cables.

Contains at least one metallic subgroup. Stress free operating window for cable contraction and tensile elongation. Optical fiber subgroup extends along the periphery of cable core. Corrugated metallic shield between cable core and jacket with water flooding compound. Optical fiber subgroup separated from metallic subgroup but binded together. No fiber overlength - tight tube construction.

A hybrid cable is also known in the prior art such as US Pat No.4365865 which comprises a plurality of optical fibers and metal conductors wound at a common lay angle. At last the metal conductors are sheathed by a fiber-reinforced resin and are prevented thereby from hockling.

The invention related to a cable that satisfies the need for an assembly which enables the fabrication of small - diameter hybrid cables that are flexible and yet immune to hockling of the contained metal conductors.

Optical fibers helically wound with sheathed metal conductors formed of a metal core surrounded by an adherent sheath of fiber - reinforced resin. Fibers of the reinforced resin are fibers selected from the group consisting of glass and aromatic polyamide fibers. Resin of the fiber-reinforced resin is a thermoset epoxy resin. Fibers of the sheath of the optical fiber and the fibers of the sheath of the metal conductor are the same. Resin of the sheath of the optical fiber and the resin of the sheath of the metal conductor are the same resin.

A composite fiber optic and electrical cable is also known in the prior art such as US Pat No.4365865 with properties which facilitates separation of the electrical components from the cable. The electrical conductors can be readily connected between a power supply and signal repeater or other electrical device.

Outer protective jacket of a sound polymer material has a melting temperature lower than the melting temperature of first polymer material. First polymer material is polyester and second polymer material is polyethylene. At least one strength member comprises an elongate steel wire. Transverse cross section of the cable is substantially circular, elliptical or trilobal in shape. Atleast one of the insulating layers includes indicia for indicating a polarity of the electrical power conductor. Indicia on the outer jacket for indicating a polarity of the conductor in a predetermined positional relationship to marking indicia.

A composite cable for conveying electrical and optical energy is also known in the prior art such as US Pat No. 6236789, to electrically energized units of an optical fiber network. Primarily to satisfy the need for a composite cable which is compact, has a small diameter, is lightweight, mechanically protects the optical fibers from damage, is scalable in terms of optical fiber and electrical conductor capacity, allows for ease of mid-span or taut-sheath fiber access without harm to either the fibers or the conductors, optimizes use of overall cable diameter for conveying electrical energy.

S-Z stranded electrical conductors around buffer tubes with optical fibers to provide a layer of conductors having a radial thickness substantially equal to the thickness of a conductor. Number of pairs of electrical conductors is less than the number of optical fibers. Resistance of the conductors and hence the gauge is selected so that the voltage drop does not exceed the predetermined value. Each conductor has a resistance and size to provide the predetermined electrical current and predetermined electrical voltage required by the electrically energized units without overheating. Pair of conductors has a safe current carrying capacity. Pair of conductors has indicia thereon and the bundles of optical fibers have indicia for identifying the electrically corresponding conductors. Buffer tube is S-Z stranded around the strength member with reversal points spaced apart by less than said predetermined longitudinal length.

A hybrid cable for distributing communications signal and power is also known in the prior art such as US Pat No.5677974, consuming time at splicing and terminal points to separate the optical fiber and metallic conductors from each other and other cable components, and a network for distributing optical signals and equipments-energizing power over wide areas.

Optical fiber is in hollow conduit. Insulated power conductors are disposed around the hollow conduit. Sheath having one or more layers encase the power conductors for providing both structural protection and dielectric properties. The conduit for facilitating the pulling of optical fiber comprises a lubricated surface. Hollow conduit comprises polyethylene. Insulated power conductors are disposed helically around the plastic conduit. A method of distributing power and optical signals to remote location

DESCRIPTION OF THE RELATED ART
All these composite or hybrid cables known in the prior art are not very much suitable for transmitting railway signaling and communication where uninterrupted communication on live status of railways become the need of passengers throughout the journey and does not meet established optical, electrical and handling standards and also does not provide proper protection of the metallic conductor from the lightning and high voltage problem.

SUMMARY
The main object of this invention is to obviate the shortcomings and limitation of the prior art composite / hybrid cables and to provide an optical Fibre / Metallic conductor composite cable in which optical fiber / quad conductor are used in one sheath to reduce extra cost of separate installation of copper conductor cables and optical fiber cables for especially for the railways for the purpose of signaling and communication.

Another object of this invention is to provide easy access of conductors or fibers without disturbing another media. This is achieved by S-Z stranded core design, which is the best design for Mid Span Access which neglects unwanted fiber joints at Copper conductor access.

It is anticipated that the present invention would be applicable for use in many different types of installations including all types of outdoor installation. More particularly the present invention is highly expected to be of use for railway signaling and communication where uninterrupted communication and online status of railways becomes the need of passenger throughout the journey.

Another object of the present invention to provide an optical fiber/metallic conductor composite cable meets established optical, electrical and handling standards.

Another object of the present invention is to provide an optical fiber/metallic conductor composite cable having fiber and metallic subgroups which can be easily separated and routed.

Another object is to provide protection of the metallic conductor of copper wires from the lightning and high voltage problem.

A further object is to provide such a cable which may be easily and economically fabricated and will enjoy a long life in operation.

BRIEF DESCRIPTION OF DRAWING(S)

The invention will now be described with reference to accompanying drawing wherein fig. 1 shows a cross sectional view of an optical fibre / metallic conductor composite cable according to an embodiment of this invention.

DETAILED DESCRIPTION OF INVENTION
Referring to fig 1 an optical fibre / metallic conductor composite cable according to an embodiment of this invention comprises an outer sheath layer (1) preferably made of polyethylene. A corrugated steel tape armouring (2) is provided to make the composite cable rodent - proof since such cables are buried directly and the outer sheath material which is generally polyethylene is prone to rodent attack. A core (6) is provided with an optical fiber sub- group (9) and an insulated metallic conductor sub-group (8).

The optical fibre sub group (9) consists of used tubes containing optical fibers and metallic conductor sub-group (8) consist of a group of four copper conductors twisted around each other forming a quad of copper conductors.

A central strength member (10) is provided to fulfill the tensile strength requirement of the composite cable.

The optical fiber loose tube and Quad conductors are preferably S-Z stranded so as to run helically parallel to one another. This makes both fiber and conductor always located on the outer periphery of the cable core for easy mid-span access during taping or branching. Simultaneously S-Z stranding of Quad conductors and loose tubes reduces extra process of manufacturing cable core and hence make the cost effective manufacturing.

The Quad conductors stranded together are coated by insulating material of different colour for the easy identification. Quad conductors are bonded together by coloured conductor binder. Preferably each conductor is made of 0.9 mm solid circular copper wire. These conductors are insulated by polyethylene insulation, which are also color coded. Pitch of the Quad is maintained so that it gives better result for electrical parameters. Packing density is precisely maintained for better electric parameters of Quad conductors.

Loose buffer tubes consist of optical fibers or ribbon fibers, all made of thermoplastics such as PBT. The empty space between the loose tube and optical fibers is filled with thixotropic jelly, which allows fiber movement in the tube and blocks water to contact the optical fibers.

Loose tubes & Quad Insulated copper conductor wires are stranded around the Central strength member (10) preferably made of fibre reinforced plastic (FRP). Flooding jelly is applied to fill the air gap between loose tubes and Quad conductors, which protect the cable core from water penetration.

Polyester tape (7) is wrapped over the cable core to protect the jelly from spreading out of the core. It is wrapped by using the two binders, to make loose tubes (9) and quad conductors (8) intact over the central strength member (10).

A protective sheathing of Polyethylene (PE) material is applied over the core, (5) which is having better dielectric constant. An armour preferably made of aluminium circular cross-section wires (4) shield this construction. These wires are helically stranded over the construction to reduce the screening effect on the Quad conductors, i.e., to protect the metallic copper conductors from the lightning damage and problems due to induced voltage. An intermediate layer of Polyethylene sheathing (3) is provided over the aluminium circular wires. Ripcords (11) are placed diagonally opposite to each other, below the sheath of optical Fibre / Metallic conductor composite cable for the easy tearing of the sheath material.

In an embodiment of the present invention, the optical fiber cable comprises an optical fiber sub group (9) and a metallic conductor sub-group (8) in a single sheath, wherein the metallic conductor subgroup comprises a plurality of copper conductors in a twisted manner. A circular central strength member (10) is provided that helps in locating both the optical fiber subgroup (9) and the metallic conductor subgroup (8) on the outer periphery of the cable core (6) and providing tensile strength to the cable. The metallic conductor sub-group (8) preferably is an insulated metallic conductor sub-group. In a preferred embodiment, the metallic conductor subgroup (8) comprises four copper conductors that are color coded for easy identification. In yet another embodiment, the metallic conductor subgroup (8) is color coded. The plurality of copper conductors are insulated by polyethylene insulation and the like materials.

The circular central strength member is preferably made of fiber reinforced plastic material (FRP). According to an embodiment, the FRPs are manufactured using high heat resistance E-glass fibers. In another embodiment, the FRPs are upcoated. In other words, the FRPs are coated with materials such as Ethylene Acrylic Acid Copolymer (EAA), High Density Poly-Ethylene Material (HDPE), Medium Density Poly-Ethylene Material (MDPE), Low Smoke Zero Halogen (LSZH) and the like. The FRPs helps in maintaining high degree of stiffness and prevents cable buckling.

In an embodiment, the FRP is a non-metallic anti-buckling FRP. In yet another embodiment, the FRP is a metallic anti-buckling FRP.

The optical fibers are placed in a loose buffer tube. The empty space between the loose tube and optical fibers is filled with jelly, which allows fiber movement in the tube and blocks water to contact the optical fibers. A flooding jelly is applied to fill the air gap between the loose tubes and quad conductors. The jelly includes, but not limited to, thixotropic jelly. A polyester tape (7) or a water blocking/swellable tape is wrapped over the cable core (6) to protect the jelly from spreading out of the core and to eliminate water ingression inside the cable core (6).

The optical fiber cable comprises a plurality of rip cords placed in the jacket to allow a quick stripping of the jacket and mid-span access. The optical fiber cable further comprises a metallic shielding including, but not limited to, a copper foil shielding, and an aluminium foil shielding. The metallic shielding allows potential equalization and a safe installation with regard to lightning strikes.

The optical fiber cable provided in the present invention combines the optical fiber and DC power that provides the DC power of about 48V. The optical fiber cable of the present disclosure is suitable for underground installation, thus are made rodent proof. According to an embodiment, the permanent bending radius of the optical fiber cable is 20D. The cable weight ranges from 90 to 370 kg/km. The nominal diameter of the optical fiber cable is 9 mm to 31.56 mm. The optical fiber cable of the present invention has a kink resistance up to 20D. The operating temperature of the optical fiber cable ranges from 90 to 990 degree Celsius.
temp range -40 to +75 degree (need clarification)

Further, the outer diameter of the optical fiber cable ranges from 9 mm to 61 mm. The optical fiber cable of the present invention has a crush resistance of 1900-5100 N, 600 sec and a tensile strength of 3000 to 7000N.

According to an embodiment, the jacket is made of a high density poly-ethylene material (hereinafter "HDPE"). In another embodiment of the present disclosure, the jacket is made of a medium density poly-ethylene material (hereinafter "MDPE"). In yet another embodiment of the present disclosure, the jacket is made of any suitable material such as PVC, LSZH, thermoplastics, nylon, water absorbing material, flame retardant and the like.
The expression ‘jacket’ or ‘outer sheath’ may be used inter-exchangeably in the present disclosure.

The above description with reference to figure is given just to understand the invention rather than to limit its scope.