Wiredrawing method and wiredrawing device for outer diameter fluctuation optical fiber perform

Abstract

The invention relates to a wiredrawing method and a wiredrawing device for an outer diameter fluctuation optical fiber perform, particularly a large-size outer diameter fluctuation optical fiber perform. Compared with an existing wiredrawing method, the wiredrawing method has the different points that a radial seal adjustable device is arranged at a furnace mouth at the upper end of a heating cavity of a wiredrawing furnace; and in the wiredrawing process, the optical fiber perform is clung to the radial seal adjustable device, so that a radial gap between the optical fiber perform and the radial seal adjustable device, i.e. the difference between the outer diameter of the optical fiber perform and the seal aperture of the radial seal adjustable device, is kept in the range of 0 to 0.2mm. According to the invention, the radial gap between the large-size perform with nonuniform outer diameter variation and the radial seal adjustable device is always kept in a small allowable gap range or tends to zero in the wiredrawing feeding process, so that the wiredrawing quality is ensured and the technical difficult problem that the large-size outer diameter fluctuation optical fiber perform cannot be directly subjected to wiredrawing processing is solved; and the yield and the processing efficiency of optical fibers are further improved and the stringiness of the single perform is also improved, so that the optical fiber manufacturing cost is further reduced.

Description

Technical field [0001] The invention relates to a method and a matching device for drawing an optical fiber preform with fluctuating outer diameter, especially large-size fluctuating outer diameter, and belongs to the technical field of optical fiber processing and manufacturing. Background technique [0002] With the development of the optical fiber preform manufacturing process, the size of the optical fiber preform is getting larger and larger. At present, the drawing length of a single optical fiber preform can reach 3500~4200km, or even 8000km, which is very effective for increasing the production capacity of optical fiber and reducing the cost of optical fiber manufacturing. However, for some large-size preforms, such as the porous glass optical fiber preforms manufactured by the external vapor deposition (OVD) process, after dehydroxylation heating treatment, they will become transparent with relatively large fluctuations in the axial outer diameter. Preform. Normally, f...

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Problems solved by technology

[0003] However, for the preform whose outer diameter fluctuates greatly in the axial direction, the gap between the preform and the glass ring will depend on the change of the outer diameter of the preform itself. If the gap between the larger outer diameter of the preform and the glass ring Within the acceptable range, it will inevitably cause the gap between the small outer diameter of the preform and the glass ri

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