OPTICAL FIBER COATING DIE ASSEMBLY HAVING INLET TUBE

• US 20190322578A1
• Filed: 04/10/2019
• Published: 10/24/2019
• Est. Priority Date: 04/20/2018
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Bookbinder, Dana Craig, Stainer, Darren Andrew, Tandon, Pushkar, Tandon, Ruchi, Wakefield, Bryan William
• Granted Patent: US 11,518,709 B2
• Time in Patent Office: Days
• CPC Class Codes: C03B 37/025 from reheated softened tubes, rods, fibres or filaments , e.g. drawing fibres from preforms draw-down of tubes, rods or preforms to reduced diameter preforms C03B37/0124
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C03C 2218/13 from melts
• CPC Class Codes: C03C 25/105 Organic claddings
• CPC Class Codes: C03C 25/1065 Multiple coatings
• CPC Class Codes: C03C 25/12 General methods of coating; Devices therefor
• CPC Class Codes: C03C 25/18 Extrusion
• CPC Class Codes: G02B 6/4486 Protective covering

Abstract

An optical fiber coating die assembly is provided. The optical fiber coating die assembly includes a housing defining a guide chamber having an inlet for receiving optical fiber and an outlet, a guide die located at the outlet of the guide chamber, and a sizing die. The optical fiber coating die assembly also includes a coating applicator disposed between the guide die and the sizing die, and a tube operatively coupled to the inlet of the guide chamber and axially aligned with the chamber to receive the optical fiber fed into the guide chamber and provide a barrier to air flow.

Claims

1. An optical fiber coating die assembly comprising:

a housing defining a guide chamber having;

an inlet for receiving optical fiber and an outlet;

a guide die located at the outlet of the guide chamber;

a sizing die;

a coating applicator disposed between the guide die and the sizing die; and

a tube operatively coupled to the inlet of the guide chamber and axially aligned with the guide chamber structured to receive the optical fiber fed into the guide chamber and provide a barrier to air flow, wherein the tube has a length of at least 5 centimeters.

2. The coating die assembly of claim 1, wherein the housing receives a purge gas that flows into the guide chamber and exits tube inlet.

3. The coating die assembly of claim 2, wherein the purge gas comprises carbon dioxide.

4. The coating die assembly of claim 2, wherein the purge gas has a gas flow rate of at least 1 SLPM.

5. The coating die assembly of claim 1, wherein the tube has a length in the range of 5-25 centimeters.

6. The coating die assembly of claim 5, wherein the tube has a length in the range of 5-12 centimeters.

7. The coating die assembly of claim 1, wherein the tube has an internal cylindrical bore with an internal diameter in the range of 0.7 millimeters to 5.0 millimeters.

8. The coating die assembly of claim 7, wherein the internal diameter is in the range of 1-3 millimeters.

9. The coating die assembly of claim 1, wherein the tube has an internal taper angle at an inlet end in the range of 3-20 degrees and the taper has a length of more than 1 centimeter.

10. The coating die assembly of claim 9, wherein the internal taper angle is in the range of 3-10 degrees.

11. An optical fiber coating die assembly comprising:

a housing defining at least a portion of a guide chamber for receiving optical fiber at an inlet, wherein the guide chamber has a length greater than 10 centimeters;

a guide die located at an exit of the guide chamber;

a sizing die; and

a coating applicator disposed between the guide die and the sizing die.

12. The coating die assembly of claim 11, wherein the guide chamber comprises a first cylindrical bore formed in the housing and a second cylindrical bore defined by an extension tube coaxially aligned with the first cylindrical bore.

13. The coating die assembly of claim 12, wherein the extension tube has a length in the range of 5-25 centimeters.

14. The coating die assembly of claim 12, wherein the extension tube has an internal taper angle at an inlet end in the range of 3-20 degrees and the taper has a length of more than 1 centimeter.

15. The coating die assembly of claim 14, wherein the internal taper angle is in the range of 3-10 degrees.

16. The coating die assembly of claim 11, wherein the housing is structured to receive a purge gas that flows into the exit of the guide chamber and exits the inlet.

17. The coating die assembly of claim 16, wherein the purge gas comprises carbon dioxide.

18. The coating die assembly of claim 12, wherein the extension tube has a cylindrical bore with an internal diameter in the range of 0.7 millimeters to 5.0 millimeters.

19. A method of coating an optical fiber, comprising the steps of:

drawing the optical fiber into a tube having an internal cylindrical bore and a length of at least 5 centimeters;

drawing the optical fiber from the tube into a guide chamber in a housing of a coating die assembly;

flowing a purge gas into the guide chamber and exiting the tube at an inlet;

passing the optical fiber through a guide die;

coating the optical fiber with a coating layer using a coating applicator; and

exiting the optical fiber through a sizing die.

20. The method of claim 19, wherein the optical fiber is drawn in a first direction at a draw speed greater than 40 meters per second and the purge gas flows at a rate of at least 1 SLPM in a second direction opposite the first direction.