UV Curing Tube Purging for Optical Fiber Coatings
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Solution Overview
Problem
Atmospheric oxygen interferes with the UV curing process of optical fiber coatings, leading to incomplete curing and deposit buildup in UV curing tubes, which attenuates the curing light and requires frequent tube replacement.
Innovation Solution
A method involving the use of a purge gas comprising oxygen to selectively clean the inner surface of the UV curing tube, while maintaining an inert environment around the optical fiber, by controlling the flow rates of inert and purge gases to prevent deposit buildup and ensure complete curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high power UV curing lamp is used to quickly cure the coating, then the curing speed is improved, but the temperature inside the curing tube increases causing coating material to volatize and form deposits on the tube surface
Solution Approach 1:
The harmful oxygen is extracted from the curing environment by introducing a nitrogen purge gas flow that sweeps across the inner surface of the curing tube, removing oxygen that would otherwise react with volatized coating material to form peroxide radicals and deposits
Solution Approach 2:
A nitrogen purge gas is introduced as an intermediary substance that flows across the inner surface of the curing tube, serving as a protective barrier between the volatized coating material and the tube surface, preventing deposit formation while allowing UV light transmission
2Reliability
If the coated fiber is cured in an inert environment to prevent oxygen interference, then the curing completeness is improved, but the cost and complexity of maintaining the inert environment increases
Solution Approach 1:
A nitrogen purge gas flow system is implemented using pneumatic principles, where pressurized nitrogen gas is introduced through inlet means and flows through the curing tube via controlled pressure differential, creating an inert atmosphere without requiring complex vacuum or sealed chamber systems
Solution Approach 2:
The nitrogen purge gas serves multiple functions simultaneously: it maintains an inert atmosphere to prevent oxygen interference with curing, sweeps volatized coating material away from the tube surface to prevent deposits, and can be easily integrated with existing curing lamp and fiber draw systems
3Illumination intensity
If the center tube is made of UV transparent quartz to allow UV light transmission, then the curing effectiveness is improved, but the tube is susceptible to coating deposits that attenuate the UV light
Solution Approach 1:
A nitrogen purge gas flow is introduced before and during the curing process to sweep across the inner surface of the quartz tube, preventing volatized coating material from condensing and forming deposits on the tube surface, thereby maintaining UV light transmission throughout the tube's operational life
Solution Approach 2:
The heat generated by the UV curing lamp, which causes coating material to volatize and potentially form deposits, is converted into a benefit by using the associated gas flow to actively sweep away volatized material, transforming a harmful thermal effect into a useful cleaning mechanism
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances curing efficiency by maintaining clear UV transmission through the tube, allowing for more complete curing of optical fiber coatings and extending the tube's operational life by reducing the need for frequent replacements.
Implementation Method 1
purging at least a portion of an inner surface of the cure tube with a purge gas comprising oxygen
Implementation Method 2
exposing the coated optical fiber to radiation
Data Source
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AI summary
Certain embodiments of the invention may include systems and methods for purging UV curing tubes. According to an exemplary embodiment of the invention, a method is provided for curing a coated optical fiber (102). The method is characterized by drawing the coated optical fiber (102) through an gas chamber (104) filled with a predetermined gas (108), drawing the fiber (102) through a cure tube (106) coupled to the gas chamber (104), and purging at least a portion of an inner surface of the cure tube (106) with a purge gas (112) as the coated optical fiber is drawn through the cure tube (106).