GB2168230A - Apparatus for curing UV-curable resin - Google Patents

Abstract

A furnace for curing a resin coat on an optical fibre 1 by ultra-violet light comprises a tube 3 through which the fibre passes, the tube 3 and a cooling duct 5 being separable into at least two portions. <IMAGE>

Description

SPECIFICATION Apparatus for curing UV-curable resin Field of the Invention The present invention relates to an improved construction of an apparatus for curing an ultraviolet (UV) - curable resin coat on an optical fiber, during the process of optical fiber production, "UV-curable resin" means the resin that can be cured by Ultraviolet light.

Background of the Invention Aconventional apparatusforcuring a UV-curable resin coat on an optical fiber is shown schematically in FIGURES 1A and 1 B wherein FIGURE 1A is a profile view and FIGURE 1B is a plan view. As shown, optical fiber 1 with a UV-curable resin coat is fed into UV furnace where the fiber is illuminated with UV lamp 6 to cause an accelerated curing ofthe resin coat. At the sametime, UVfurnace 5, UV lamp 6 and electrical components8,forturning on oroffthe lamp,are cooled by external airthat is fed into the system through filter7 and discharged through duct9. Inthis instance, the optical fiber 1 must be insensitive to the stream of cooling air and the UV-curable resin coat on the fiber must be effectively cu red by UV radiation.

In orderto meet these reqirements, optical fiber 1 is isolated from the stream of cooling air by means of glass pipe 3 and a rubber sealant 11 that separates the interior of sealing cases 2 and 4from the space where cooling airflows, and at the sametime,the spacethat is defined by the sealing cases 2 and 4through which the optical fiber 1 passes is filled with purging N2 gas 10that prevents external airfrom coming into that space. An inert gas such as N2 gas 10 that is blown into the fiber channel prevents the energy of UV radiation from being spent in the reaction forming 02, thus increasing the efficiency of curing the UV resin coat.

Continuous production of an elongated material such as optical fibers always starts with a drawing operation wherein the optical fiber is drawn through a channel formed by sealing case 2, glass pipe 2 and sealing case 4. The fiber being drawn is either an uncoated glass preform of a coated fiber, and the glass preform involves considerable difficulty in handling, because, first fall, it is verythin (100-200 um in diameter) and secondly, it will easily stick to the wall of the glass pipe owing to static electricity or volatile components in the UV resin coat.

This difficultly is particularly great today where the use of nore than one unit of UV furnace is the usual practice to meet the need for high-speed coating operations.

From an operation viewpoint, the only feasible equipment layout isto arrange a plurality of UV furnaces in the vertical direction, and so, as the number of the UV furnaces that have to be set up is increased, a more complicated layout becomes necessary as is borne out by the use of ladders with a view to ensuring an adequate working spaceforoperators.

As described above, the conventional apparatus for curing a UV-curable resin coat on an optical fiber involves several problems and objects which slow manufacturing speed and increase costs, thereby causing inefficiency.

Summary of the Invention The present invention improves the efficiency ofthe fiberdrawing operation, by providing a simpler setup apparatus, and realizing a more effective use of working space. The apparatus of the present invention for curing a UV-curable resin is characterized in that a structural unitthatforms a passage or space which provides the UV curing effect for the material or product two be cured is arranged so that it can be divided into two or nore sections either automatically or manually.

Thus, the present invention for cu ring a UV-curable resin coat on an optical fiber is divided into two or more sections so that the fiber drawing operation, which is the first step ofthe UV curing process, may be accomplished with greater ease leading to operational efficencies.

Brief description of the Drawings FIGURES 1A and 1 B are profile and plan views, respectively, of a conventional UV apparatus; and FIGURES 2A and 2B are profile and plan views, respectively, of a UV curing apparatus in accordance with one example ofthe present invention.

Detailed description of the Invention An embodiment of the present invention will now be described with reference to FIGURES 2A and 2B. As shown, structural units that form channels and spaces which provide the UV curing effect, namely, a sealing case 2, glass pipe 3, sealing case 4, rubber seal 11 and a UVfurnace 5, are each divided into, for example, two sections.

The divided components are so designed that they can independently or simultaneously move away from ortowardthe path line ofthe optical fiber 1 . The movement ofthe divided components may be realized automatically or manually. The structural units of the apparatus mentioned above may also be divided into three or more sectionswithout affecting the purpose ofthe invention.

The present invention as envisaged by the illustrated embodiment providesforgreaterease in performing the fiber drawing operation which is the first step of the UV curing process in a UVfurnace. If the direction in which the divided structural units of the UVfurnace separate away from the path line ofthe optical fiber is indicated by the notation " UV Furnace Open" while the direction in which the separated units come close together to make an integral entity is indicated by "UV Furnace Closed", an operator who wants to conductthe firstfiber drawing operation may simply put the apparatus into the state of "UV Furnace Open" and pull the optical fiberthrough the apparatus along its path line. The operatorthen restores the invention to the state of "UV Furnace Closed" and will usethe UVfurnace in the same manneras employed in the prior artforthe curing operation. This advantage of the present invention is not lost even if a plurality of UVfurnaces are set up in a vertical arrangement.

Accordingly, two primary advantages of the present invention are: (1) the efficency of operation of the separable UVfurnace is significantly improved over conventional UV furnaces; and (2) the effort to ensure necessary working space is not as highly dependent onthe layout and number of UV furnaceswhenthe present invention is used.

Claims (4)

1. An aparatus forcuring a curable resin coat on a fiber by using ultra-violet light, said apparatus comprising: a furnace for receiving said resin coatedfiberwhich is to be cured, said furnace being separatable into two or more portions; a glass pipe disposed within said furnace, said resin coated fiber being positioned within said glass pipe during the curing operation, said glass pipe being separable into two or more portions; and glass pipe sealing cases forsealing the two ends of said glass pipe from the interior said furnace, each one of said glass pipe sealing cases being separable into two or more portions.

2. An apparatus as in claim 1, further comprising: an ultra violet lamp disposed within one of said two or more furnace portions; and control means disposed within said one furnace portion for switching on and offsaid ultra violet lamp.

3. An apparatus as in claim 1, further comprising: means for introducing cooling air being disposed in one of said two or more furnace portions; meansforexhausting said cooling air being disposed in another one of said two or morefurnace portions; and means for introducing an inert gas within said glass pipe said inert gas introducing means being mounted overran assembly of said glass pipe portions.

4. An apparatus for curing a resin coated fiber by using ultra-violet light su bstantially as hereinbefore described with reference to Figures 2a and 2b of the accompanying drawings.