Gas furnace design for low-temperature and low-speed fiber drawing process

A kind of fiber drawing machine based on gas furnace is introduced in this paper. Furnace vents were designed with a special eccentric angle and elevation angle to form a specific size focus ring. The high temperature area of the furnace is focused on gas ring. Different heating furnace structure for different preform dimension can be obtained by changing the eccentric angle and elevation angle. Gas heating source was selected through analysis and comparison of hydrocarbons and acetylene gas temperature characteristics. In the experiments, we draw out a hollow fiber at about 1280°C and got a minimum optical fiber drawing speed of 1m / min. The furnace temperature can also be set below this temperature by gas selection and flow control to draw out various low temperature optical fiber.