Fiber optic cable with composite polymeric/metallic armor
View Patent ↗A fiber optic cable includes: a plurality of optical fibers; a tube circumferentially surrounding the optical fibers, the tube being formed of a first polymeric material; an armor circumferentially surrounding and fixed relative to the tube, the armor being formed of a metallic material; and a jacket circumferentially surrounding the armor, the jacket being formed of a second polymeric material. In this configuration, the cable can provide the requisite mechanical, electrical, handling and connectorizing properties for use in applications such as pavement crossings.
1. A fiber optic cable, comprising:
a plurality of optical fibers;
a tube circumferentially surrounding the optical fibers, the tube being formed of a first polymeric material;
an armor circumferentially surrounding and fixed relative to the tube to form a composite structure, the armor being formed of a metallic material, wherein the armor includes a longitudinally-disposed welded seam; and
a jacket circumferentially surrounding the armor, the jacket being formed of a second polymeric material.
2. The fiber optic cable defined in claim 1 , wherein the first polymeric material comprises a material selected from the group consisting of: polypropylene, polyethylene and polybutyl terephthalate.
3. The fiber optic cable defined in claim 1 , further comprising a water-blocking material within the tube interspersed with the plurality of optical fibers.
4. The fiber optic cable defined in claim 3 , wherein the water-blocking material is a filling gel.
5. The fiber optic cable defined in claim 3 , wherein the water-blocking material is a dry powder.
6. The fiber optic cable defined in claim 1 , wherein the armor is formed of a metallic material selected from the group consisting of: stainless steel; copper; and aluminum.
7. The fiber optic cable defined in claim 1 , wherein the armor is formed of copper.
8. The fiber optic cable defined in claim 1 , wherein the armor has a thickness of between about 0.008 and 0.020 inches.
9. The fiber optic cable defined in claim 8 , wherein the armor has an outer diameter of between about 0.230 and 0.350 inches.
10. The fiber optic cable defined in claim 1 , further comprising a layer of superabsorbant polymer powder between the tube and the armor.
11. The fiber optic cable defined in claim 10 wherein the superabsorbant powder is applied in a hot melt matrix material.
12. The fiber optic cable defined in claim 1 , wherein the armor is fixed to the tube via an interference fit.
13. The fiber optic cable defined in claim 1 , wherein the second polymeric material comprises medium density polyethylene.
14. The fiber optic cable defined in claim 1 , wherein the cable has a length of between about 50 and 1,000 feet.
15. A method of installing a fiber optic cable at a field site, comprising the steps of:
forming an elongate slot in an installation substrate;
positioning a fiber optic cable of claim 1 in the installation substrate; and covering the slot and fiber optic cable with additional installation substrate material to embed the fiber optic cable therein.
16. The method defined in claim 15 , wherein the installation substrate comprises a material selected from the group consisting of: pavement; asphalt; cement; concrete; and soil.
17. The fiber optic cable defined in claim 1 , wherein the armor has a thickness of between about 0.008 inch and 0.020 inch.
18. The fiber optic cable defined in claim 17 , wherein the armor has an outer diameter of between about 0.23 inch and 0.35 inch.
19. The fiber optic cable defined in claim 17 , wherein the jacket has a thickness of between about 0.020 and 0.070 inch.
20. An fiber optic cable installation site, comprising:
an installation substrate; and
a fiber optic cable embedded in the installation substrate, the fiber optic cable comprising:
a plurality of optical fibers;
a tube circumferentially surrounding the optical fibers, the tube being formed of a first polymeric material;
an armor circumferentially surrounding and fixed relative to the tube to form a composite structure, the armor being formed of a metallic material; and
a jacket circumferentially surrounding the armor, the jacket being formed of a second polymeric material;
wherein the installation substrate includes a cap that is exposed to the atmosphere, and wherein the cap comprises a material selected from the group consisting of: pavement; asphalt; cement; and concrete.
21. The fiber optic cable installation site defined in claim 20 , wherein the installation substrate comprises a material selected from the group consisting of: pavement; asphalt; cement; concrete; and soil.
22. The fiber optic cable installation site defined in claim 20 , wherein the first polymeric material comprises a material selected from the group consisting of: polypropylene, polyethylene and polybutyl terephthalate.
23. The fiber optic cable installation site defined in claim 20 , wherein further comprising a water-blocking material within the tube interspersed with the plurality of optical fibers.
24. The fiber optic cable installation site defined in claim 23 , wherein the water-blocking material is a filling gel.
25. The fiber optic cable installation site defined in claim 23 , wherein the water-blocking material is a dry powder.
26. The fiber optic cable installation site defined in claim 20 , wherein the armor is formed of a metallic material selected from the group consisting of: stainless steel; copper; and aluminum.
27. The fiber optic cable installation site defined in claim 20 , wherein the armor is formed of copper.
28. The fiber optic cable installation site defined in claim 20 , wherein the armor includes a longitudinally-disposed welded seam.
29. The fiber optic cable installation site defined in claim 20 , wherein the armor has a thickness of between about 0.008 and 0.020 inches.
30. The fiber optic cable installation site defined in claim 29 , wherein the armor has an outer diameter of between about 0.230 and 0.350 inches.
31. The fiber optic cable installation site defined in claim 20 , further comprising an adhesive layer between the tube and the armor to fix the tube relative to the armor.
32. The fiber optic cable installation site defined in claim 31 , wherein the adhesive layer comprises ethylene acrylic acid.
33. The fiber optic cable installation site defined in claim 20 , wherein the armor is fixed to the tube via an interference fit.
34. The fiber optic cable installation site defined in claim 20 , wherein the second polymeric material that forms the jacket comprises medium density polyethylene.
35. The fiber optic cable installation site defined in claim 20 , wherein the cable has a length of between about 50 and 1,000 ft.
36. A method of manufacturing a fiber optic cable, comprising the steps of:
providing a plurality of optical fibers residing in a tube formed of a first polymeric material;
forming a metallic armor to circumferentially surround and be fixed relative to the tube such that the tube and armor form a composite structure, wherein the step of forming a metallic armor comprises bending a thin metallic strip around the tube;
welding a longitudinally-disposed seam formed by lateral edges of the thin metallic strip; and forming a jacket of a second polymeric material to circumferentially surround the armor.
37. The method defined in claim 36 , wherein the first polymeric material is selected from the group consisting of: polypropylene, polyethylene and polybutyl terephthalate.
38. The method defined in claim 36 , wherein the thin metallic strip has a thickness of between about 0.008 and 0.020 inches.
39. The method defined in claim 36 , further comprising the step of swaging the metallic armor to cause it shrink in diameter.
40. The method defined in claim 39 , wherein the step of forming a polymeric jacket comprises extruding the second polymeric material around the armor.
41. The method defined in claim 36 , wherein the tube includes an adhesive layer that adheres to the armor.
42. A fiber optic cable, comprising:
a plurality of optical fibers;
a tube circumferentially surrounding the optical fibers, the tube being formed of a first polymeric material;
an armor circumferentially surrounding and fixed relative to the tube to form a composite structure, the armor being formed of a metallic material, wherein the armor includes a longitudinally-disposed welded seam; and
a jacket circumferentially surrounding the armor, the jacket being formed of a second polymeric material;
the fiber optic cable further comprising an adhesive layer between the tube and the armor to fix the tube relative to the armor.