| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a method for producing an optical fiber in which reduction in fiber strength can be decreased to prevent disconnection. <P>SOLUTION: The method includes: sequentially providing a clean air chamber 23 for slowly cooling a glass fiber 13 drawn out of a wire drawing furnace 21 and a forced cooling chamber 25 for subjecting the glass fiber to forced cooling; monitoring on-line the cleanliness in the clean air chamber 23 and the forced cooling chamber 25; simultaneously monitoring the inner pressure of both the chambers 23 and 25; and controlling the amounts of clean air 31 and dried air 33 to be supplied to both the chambers 23 and 25, respectively, so that the amount of dust having a diameter of 0.5 μm or more in the clean air chamber 23 and the forced cooling chamber 25 is kept at ten pieces per cubic meter or less, and the inner pressure of the forced cooling chamber 25 is kept higher than that of the clean air chamber 23 and the inner pressures of both the chambers 23 and 25 are higher than that of the outside 29 of the chambers. <P>COPYRIGHT: (C)2012,JPO&INPIT |
