Heating furnace for a device for drawing a plastic optical fiber
AssigneeSumitomo Wiring Systems, Ltd.
InventorShinichi Matsumoto
Life of this patent
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Abstract
A heating furnace is used in a drawing device for drawing a base material made of plastic. The base material is fed into the heating furnace, melted under heat and drawn into a plastic optical fiber. The heating furnace is divided into a pre-heating zone located upstream and a heat-melting zone located downstream in the advancing direction of the base material and of the plastic optical fiber made therefrom. The preheating zone includes a pre-heater for pre-heating the base material, while the heat-melting zone includes a melting heater for melting the base material. Both zones are controllable independently so as to give an appropriate temperature for each zone.
Claims20
A heating furnace for use in a drawing device for drawing a base material made of plastic, the base material being fed into said heating furnace, melted under heat and drawn into a plastic optical fiber, said heating furnace comprising:
- a pre-heating zone located upstream, said pre-heating zone comprising a pre-heater for pre-heating the base material;
- and
- a heat-melting zone located downstream in the advancing direction of the base material and of the plastic optical fiber made therefrom, said heat-melting zone comprising a melting heater for melting the base material,
- wherein said furnace is configured such that said pre-heating zone and said heat-melting zone are insulated from one another and are controllable independently so as to allow an appropriate temperature for each zone.
A method for enhancing the drawing line speed of a furnace used in a drawing device for drawing a base material into an optical fiber, said method comprising:
- feeding a base material into a pre-heating zone of the furnace, said pre-heating zone including a pre-heater for pre-heating said base material;
- setting the temperature in said pre-heating zone to be lower than the glass transition temperature of said base material;
- heating said base material to a predetermined temperature inside said pre-heating zone;
- passing said base material from said pre-heating zone to a heat-melting zone, said heat-melting zone including a melting heater for melting said base material;
- insulating said pre-heating zone from said heat-melting zone;
- setting the temperature in said heat-melting zone to be higher than the glass transition temperature of said base material so as to melt it;
- and
- melting said base material in said heat melting zone while simultaneously drawing said base material into an optical fiber,
- whereby the drawing line speed of the furnace can be increased without slowing down the heat transfer to the base material, cutting off the optical fiber, or deteriorating the accuracy of the diameter of the optical fiber.
Dependencies are inferred from the claim text.