Purge Device for Optical Fiber Draw System
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Solution Overview
Problem
The existing fiber draw systems face issues with optical fiber breaks due to graphite and SiO particles that cause erosion and deposition in the furnace, leading to flaws and defects in the fiber, which are exacerbated by particulates transported into the slow-cooling device, resulting in increased product losses and defects.
Innovation Solution
An optical fiber production system that includes a slow-cooling treatment device with a purge gas system, where an inert gas is used to flush the preform and fiber, and a nozzle assembly that injects purge gas to strip the boundary layer and particles from the fiber, reducing their entry into the slow-cooling treatment device, thereby minimizing fiber breaks and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If graphite is used in the fiber draw furnace for high temperature operation, then the furnace can operate at high temperatures, but graphite erosion and SiO particle formation occur causing fiber breaks and defects
Solution Approach 1:
A water-cooled shield is introduced as an intermediary component between the graphite furnace wall and the optical fiber. This shield acts as a protective barrier that intercepts SiO particles and prevents them from adhering to the fiber surface, thereby eliminating the harmful effect while maintaining the high temperature operation capability
Solution Approach 2:
An inert gas atmosphere (argon or nitrogen) is maintained in the furnace to prevent oxidation reactions. This inert environment suppresses the formation of SiO vapor and particles by preventing the oxidation of silicon from the graphite crucible, thereby reducing the harmful particulate matter that causes fiber breaks
2Temperature
If the slow-cooling treatment device has a small diameter to maintain controlled cooling, then cooling control is improved, but particles are in closer proximity to the fiber increasing point defects and breaks
Solution Approach 1:
A water-cooled shield is positioned within the slow-cooling treatment device to create a protected zone around the fiber. This shield serves as an intermediary barrier that blocks SiO particles from reaching the fiber surface during the slow-cooling process, allowing the device to maintain its small diameter for controlled cooling while preventing particle-induced defects
Solution Approach 2:
The harmful SiO particles are effectively removed from the vicinity of the fiber by the water-cooled shield, which captures and retains particles away from the fiber path. This extraction of harmful particles from the critical zone allows the fiber to cool in a protected environment
3Productivity
If equipment and process changes are made to improve fiber draw, then production capabilities are enhanced, but the number of particulates flowing into the slow-cooling device increases
Solution Approach 1:
The water-cooled shield serves as a universal protective intermediary that can be integrated into various fiber draw configurations. It effectively intercepts particles regardless of the specific equipment changes or process parameters, thereby decoupling productivity enhancements from particulate generation issues
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
The system effectively reduces the number of particles entering the slow-cooling treatment device by over 90%, leading to increased fiber yield and reduced defects, while maintaining a controlled cooling rate and pressure to enhance fiber quality.
Implementation Method 1
flushing the preform and the fiber with an inert gas flow for protecting the preform and the fiber from contamination
Implementation Method 2
a nozzle assembly that injects purge gas to strip the boundary layer and particles from the fiber
Implementation Method 3
The system effectively reduces the number of particles entering the slow-cooling treatment device by over 90%
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An optical fiber production system is provided which includes a slow-cooling device and a purge device positioned above the slow-cooling device. The purge device includes a tube defining an inlet. An optical fiber extends through the slow-cooling device and the purge device. The purge device is configured to inject a purge gas through the inlet and against the optical fiber.