摘要 |
In an optical fiber manufacturing method, the cooling device and the coating device are connected in an airtight manner and by preventing a cooling gas, flowing inside the cooling device, from flowing into the coating device by a meniscus of resin inside of the coating device, a flow of the cooling gas inside the cooling device is discharged to an outside of an upper end of the cooling device as an upward stream; helium gas as the cooling gas flows into a lower portion of the cooling device and carbon dioxide gas as the cooling gas which is separated from the helium gas flows into a side lower than a position where the helium gas flows in, during the forcible cooling; and a flow rate of the helium gas and a flow rate of the carbon dioxide gas are individually controlled. |