Gas leak proof corrugated sheath design for reducing friction in optical fiber cables

Patent metadata

Field	Value
Publication number	US-11624883-B2
Application number	US-202117214861-A
Country	US
Kind code	B2
Filing date	Jun 7, 2021
Priority date	Oct 27, 2020
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

A gas leak proof corrugated sheath design for reducing friction in an optical fiber cable (100) includes a plurality of ribbons (102) in a plurality of ribbon bundles (104), one or more water swellable yarns (110), a first layer (106), one or more ripcords (108), one or more strength members (112) and a second layer (114). The first layer, surrounding the plurality of ribbon bundles by the second layer having a plurality of ribs (116) and a plurality of grooves (118) to reduce number of contact points between the optical fiber cable and a duct to reduce coefficient of friction between the second layer and an inner surface of the duct.

First claim

What is claimed is:

1. A corrugated sheath for an optical fiber cable, comprising:
a plurality of ribs on an external surface of the corrugated sheath, wherein the plurality of ribs is defined by corrugation ratio up to 11%, wherein a number of ribs per unit outer diameter of the optical fiber cable is 1.2 to 6.2.

2. The corrugated sheath as claimed in claim 1 , wherein the corrugation ratio is defined as

N
g

*
W
*
H
*
100

π
⁡
(

OD
2

-

ID
2

)

*
0.25

wherein,
N g =number of grooves
W=width of groove
H=depth of groove
OD=outer diameter of the corrugated sheath
ID=Inner diameter of the corrugated sheath.

3. The corrugated sheath as claimed in claim 1 , wherein the corrugated sheath ensures no gas leak from a joint closure box filled with air or any other gas with a gauge pressure of 0.3±0.03 bar.

4. The corrugated sheath as claimed in claim 1 , wherein a temperature inside a gas sealing system is in a range of 15° to 25° C.

5. The corrugated sheath as claimed in claim 1 , wherein a tracer gas used for testing is 5% Hydrogen and 95% Nitrogen or any other tracer gas.

6. The corrugated sheath as claimed in claim 1 , wherein the plurality of ribs has a height up to 0.3 mm.

7. The corrugated sheath as claimed in claim 1 , wherein a distance between successive ribs of the plurality of ribs is 0.2 to 2.5 mm.

8. The corrugated sheath as claimed in claim 1 , wherein the corrugated sheath has one or more strength members embedded into the corrugated sheath.

9. The corrugated sheath as claimed in claim 1 is used in the optical fiber cable, wherein the optical fiber cable has a central strength member.

10. The corrugated sheath as claimed in claim 1 , wherein all ribs of the plurality of ribs are of same height and all grooves of a plurality of grooves are of same depth.

11. The corrugated sheath as claimed in claim 1 , wherein an inner surface of the corrugated sheath is smooth or non-corrugated.

12. The corrugated sheath as claimed in claim 1 , wherein the optical fiber cable further comprises a first layer, wherein the first layer is a tape layer.

13. The corrugated sheath as claimed in claim 12 , wherein the tape layer is composed of a polyester, a polyacrylate swelling powder, and a corrosion inhibitor.

14. The corrugated sheath as claimed in claim 1 , wherein the optical fiber cable comprises a plurality of ribbons, a plurality of ribbon bundles, a first layer, one or more ripcords, one or more water swellable yarns, one or more strength members and a second layer.

15. The corrugated sheath as claimed in claim 14 , wherein the one or more ripcords is placed between the first layer and the second layer.

16. The corrugated sheath as claimed in claim 15 , wherein the plurality of ribbons have a pitch of 250 μm.

17. The corrugated sheath as claimed in claim 14 , wherein the one or more strength members are embedded in the second layer.

18. The corrugated sheath as claimed in claim 17 , wherein the one or more strength members is made of a fiber reinforced plastic (FRP) or an aramid reinforced plastic (ARP).

19. The corrugated sheath as claimed in claim 14 , wherein the water swellable yarn is located in a core of the optical fiber cable.

Assignees

• Sterlite Tech Ltd

Inventors

• Sahoo Kishore
• Shukla Vikash

Classifications

• G02B6/567

  for ribbon cables · CPC title

• G02B6/4435 Primary

  Corrugated mantle · CPC title

• G02B6/52 Primary

  using fluid, e.g. air · CPC title

• G02B6/4434

  Central member to take up tensile loads · CPC title

• G02B6/4498

  Physics · mapped topic