JPH1087347A - Uv curing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an UV curing device which is capable of exhibiting a steam adherence preventing effect of an UV curing resin to the inner surface of an inner tube even at a latter half part side of the inner tube. SOLUTION: An optical fiber coated with the UV curing resin 2 passing along a center in the inner tube 1 is irradiated with UV by an UV ray source 3 from outside of the inner tube 1. An innert gas is blown off in the center direction of the inner tube 1 by an innert gas blowing-off means 6 at one opening 1a side of the inner tube 1 and an adherence preventing gas is blown off by an adherence preventing gas blowing-off means 7 so as to flow along the inner wall of the inner tube 1. At another opening 1b side of the inner tube 1, the innert gas is sucked from a center of the opening 1b by an inert gas suction means 18 and the adherence preventing gas is sucked along the inner periphery of the inner tube 1 by an adherence preventing gas suction means 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet curing apparatus for irradiating an ultraviolet curing resin coated optical fiber passing through an inner tube with ultraviolet light from outside the inner tube to cure the ultraviolet curing resin on the surface of the optical fiber. Things.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a conventional ultraviolet curing apparatus of this kind. This ultraviolet curing apparatus irradiates ultraviolet rays from outside the inner tube 1 to an inner tube 1 made of quartz glass through which ultraviolet rays pass and an ultraviolet curing resin coated optical fiber 2 passing along the center of the inner tube 1. An ultraviolet light source 3 such as an ultraviolet lamp; an elliptical mirror 4 for reflecting ultraviolet light emitted from the ultraviolet light source 3 so as to impinge on an ultraviolet-curable resin-coated optical fiber 2 in the inner tube 1; Case 5 for housing ultraviolet light source 3 and mirror 4
And an inert gas blowing means 6 for blowing an inert gas such as nitrogen gas toward the center of the inner tube 1 on one opening 1a side of the inner tube 1; An anti-adhesion gas blowing means 7 for blowing out an anti-adhesion gas such as nitrogen gas along the inner wall of the tube 1 is provided.

[0003] The inert gas blowing means 6 has a gas container 9 having a through hole 8 for the ultraviolet-curable resin-coated optical fiber 2 at the center thereof, and the inside of the gas container 9 is concentric with the ultraviolet-curable resin-coated optical fiber 2. A partition 10 for partitioning the inner chamber 9a and the outer chamber 9b, a gas blowing hole 11 dispersed and opened in a circumferential direction of the partition 10, and a gas supply port 12 for supplying an inert gas from the outside to the outer chamber 9b. And one piece which is inserted into the center of one opening 1a of the inner pipe 1 from the bottom of the gas container 9 in communication with the inner chamber 9a and blows out an inert gas along the center of the inner pipe 1. And a gas blowing nozzle 13 formed of a pipe.

The anti-adhesion gas blowing means 7 has a through hole 14 for a gas blowing nozzle 13 at the center and is disposed on the outer periphery of the lower part of the gas blowing nozzle 13 and has a case centered on one opening 1a of the inner pipe 1. Gas container 1 installed on 5
5, a gas supply port 16 for supplying an anti-adhesion gas such as nitrogen gas from the outside into the gas container 15, and an anti-adhesion along the inner wall of one opening 1a of the inner tube 1 from the bottom of the gas container 15. And a gas blowing nozzle body 17 having a plurality of gas blowing holes 17a in the circumferential direction for blowing gas.

Prior to such an ultraviolet curing apparatus, there is provided a drawing step of drawing an optical fiber from an optical fiber preform,
A resin coating step of coating the optical fiber obtained in the drawing step with an ultraviolet-curable resin is provided, and the ultraviolet-curable resin-coated optical fiber 2 is formed through these steps.

The ultraviolet-curable resin-coated optical fiber 2 thus obtained passes through the center of the inner tube 1 through the through hole 8 of the inert gas blowing means 6 and the center of the gas blowing nozzle 13. When the ultraviolet curable resin-coated optical fiber 2 passes through the center of the inner tube 1, the ultraviolet light emitted from the ultraviolet light source 3 is irradiated to cure the ultraviolet curable resin. Such curing of the ultraviolet curable resin needs to be performed in a state where oxygen is removed from around the ultraviolet curable resin coated optical fiber 2. For this reason, the inert gas is blown along the center of the inner tube 1 by the inert gas blowing means 6 to perform the operation in an atmosphere excluding oxygen. Also, at this time, the ultraviolet curable resin coated on the surface of the optical fiber is partially evaporated by the irradiation of ultraviolet light and adheres to the inner surface of the inner tube 1, and the transparency of the inner tube 1, that is, the transmitted dose of the ultraviolet light gradually increases. As a result, the curing efficiency of the ultraviolet curable resin decreases, so that an adhesion preventing gas is caused to flow along the inner wall of the inner tube 1 to prevent adhesion of the resin vapor.

[0007]

However, in such a conventional ultraviolet curing apparatus, an inert gas G1 flowing through the center of the inner tube 1 and an adhesion preventing gas flowing along the inner wall of the tube 1 as shown in FIG. G2 is mixed with the latter half of the inner tube 1 so that the effect of the adhesion preventing gas G2 cannot be obtained.

[0008] It is an object of the present invention to provide an ultraviolet curing apparatus capable of exerting the effect of preventing the vapor of the ultraviolet curing resin from adhering to the inner surface of the inner tube even in the latter half of the inner tube.

[0009]

SUMMARY OF THE INVENTION The present invention provides an inner tube through which ultraviolet rays pass, and an ultraviolet ray for irradiating ultraviolet rays from outside the inner tube to an ultraviolet-curable resin-coated optical fiber passing along the center of the inner tube. A light source, an inert gas blowing means for blowing an inert gas toward the center of the inner tube at one opening side of the inner tube, and adhering along the inner wall of the inner tube at one opening side of the inner tube. The present invention is to improve an ultraviolet curing apparatus provided with an adhesion prevention gas blowing means for blowing out a prevention gas.

In the ultraviolet curing device according to the present invention,
An inert gas suction means which is opened at the center of the opening on the other opening side of the inner pipe and sucks an inert gas; and an opening along the inner circumference of the inner pipe on the other opening side of the inner pipe. And an anti-adhesion gas suction means for sucking the anti-adhesion gas.

With this configuration, the inert gas can be sucked by the inert gas suction means at the center of the other opening of the inner tube, and the adhesion preventing gas can be sucked along the inner periphery of the other opening of the inner tube. The adhesion preventing gas can be sucked by the means. Therefore, the anti-adhesion gas can smoothly descend along the inner circumference of the other of the inner tubes, and the effect of the anti-adhesion gas can be exerted on the rear half of the inner tube.

[0012]

1 and 2 (A) and 2 (B) show a first embodiment of an ultraviolet curing apparatus according to the present invention. Parts corresponding to those in FIG. 4 described above are denoted by the same reference numerals.

In the ultraviolet curing device of this embodiment, the structure on the upper side of the inner tube 1 is the same as that of FIG. In the device of this example,
An inert gas suction means 18 for opening the center of the opening 1b at the lower end opening 1b side, which is the other opening 1b side of the inner tube 1, for sucking an inert gas; An anti-adhesion gas suction means 19 that opens along the inner periphery of the inner tube 1 on the side of the opening 1b and suctions the anti-adhesion gas is provided.

The inert gas suction means 18 is provided with a gas container 21 having a through hole 20 of the ultraviolet-curable resin-coated optical fiber 2 at the center, and the inside of the gas container 21 is concentric with the ultraviolet-curable resin-coated optical fiber 2. A partition wall 22 for partitioning into an inner chamber 21a and an outer chamber 21b, a gas suction hole 23 distributed and opened in a circumferential direction of the partition wall 22,
A gas exhaust port 24 for sucking out and exhausting the inert gas;
From one pipe that is inserted into the center of the other opening 1b of the inner pipe 1 from the upper part of the gas container 21 in communication with the inner chamber 21a and sucks an inert gas along the center of the inner pipe 1 And a gas suction nozzle 25.

The anti-adhesion gas suction means 19 includes a gas container 26 provided concentrically on the outer periphery of the gas suction nozzle 25 on the gas container 21 and an inner pipe at the outer periphery of the gas suction nozzle 25. An annular gas suction nozzle body 27 that opens along the inner periphery of 1 and sucks an anti-adhesion gas, and a gas exhaust port 28 that suctions the inside of the gas container 26 from the outside and exhausts the anti-adhesion gas. I have.

The gas suction nozzle 27 is shown in FIG.
As shown in (B), a through hole 30 is provided at the center of the disc body 29 to penetrate the gas suction nozzle 25, and a large number of gas suction holes 31 are provided along the outer periphery of the disc body 29. ing.

In such an ultraviolet curing apparatus, on one side of the opening 1a of the inner tube 1, an inert gas is flowed along the center of the inner tube 1 by the inert gas blowing means 6, and the inner wall of the inner tube 1 Flow the anti-adhesion gas along. In particular, the anti-adhesion gas flowing along the inner wall of the inner tube 1 has a higher flow rate than the inert gas flowing along the center.

On the other hand, on the other opening 1b side of the inner tube 1,
At the center thereof, the inert gas is sucked by the inert gas suction means 18, and the adhesion preventing gas suction means 1 is drawn along the inner circumference of the inner pipe 1.
At 9, the anti-adhesion gas is sucked. Therefore, unlike the conventional case, the anti-adhesion gas can smoothly descend along the inner circumference of the inner tube 1 even on the other side of the inner tube 1, and the effect of the anti-adhesion gas can be reduced even in the rear half of the inner tube 1. Can be demonstrated.

In this case, nitrogen gas may be used as the anti-adhesion gas, but carbon dioxide gas (CO.sub.2) is preferable when flowing from the top to the bottom so that it can be easily lowered even with a small amount.

According to experiments, the ultraviolet curing apparatus of the present example enabled continuous drawing for 1000 km or 3 to 4 days.

FIG. 3 shows another example of the gas suction nozzle body 27. In the gas suction nozzle body 27 of this example,
Each gas suction hole 31 is provided to be inclined in the circumferential direction of the disk body 29. Similarly, in the gas blowing nozzle body 17, each gas blowing hole 17a is provided to be inclined in the circumferential direction.

When the gas blowing holes 17a and the gas suction holes 31 are provided so as to be inclined in the circumferential direction as described above, the anti-adhesion gas can be swirled along the inner wall of the inner pipe 1, and the anti-adhesion gas can be removed. The flow can be more stable than the parallel flow.

Some constituent features of the inventions disclosed in the present specification are as follows.

(1) An inner tube through which ultraviolet rays pass, an ultraviolet light source for irradiating ultraviolet rays from outside the inner tube to an ultraviolet curing resin-coated optical fiber passing along the center of the inner tube, An inert gas blowing means for blowing an inert gas toward the center of the inner tube at one opening side, and an adhesion preventing gas flowing along the inner wall of the inner tube at one opening side of the inner tube. An ultraviolet curing device having an adhesion preventing gas blowing means for blowing the inert gas, wherein an inert gas suction means for opening the center of the opening on the other opening side of the inner tube and sucking the inert gas; An ultraviolet curing device, further comprising: an anti-adhesion gas suction unit that opens along the inner circumference of the inner tube on the other opening side of the inner tube and suctions the anti-adhesion gas.

(2) The anti-adhesion gas blowing means is configured to blow the anti-adhesion gas so as to swirl and flow along the inner wall, and the anti-adhesion gas suction means swirls along the inner wall. An ultraviolet curing device characterized in that it is capable of sucking a flowing adhesion preventing gas.

(3) The flow rate of the anti-adhesion gas blown by the anti-adhesion gas blowing means is set to be faster than the flow rate of the inert gas blown by the inert gas suction means. The ultraviolet curing device according to (1) or (2).

(4) The ultraviolet curing device according to (1), (2) or (3), wherein the adhesion preventing gas is carbon dioxide.

[0028]

In the ultraviolet curing apparatus according to the present invention, an inert gas suction means which opens at the center of the other opening on the other opening side of the inner tube and sucks an inert gas, and the other of the inner tube. Anti-adhesion gas suction means for opening the inner pipe along the inner circumference of the inner pipe and sucking the anti-adhesion gas is provided at the center of the other opening side of the inner pipe. Thus, the inert gas can be sucked, and the anti-adhesion gas can be sucked by the anti-adhesion gas suction means along the inner circumference on the other opening side of the inner tube. For this reason, the anti-adhesion gas can smoothly descend along the inner circumference of the inner tube even on the other side of the inner tube,
The effect of preventing the vapor of the ultraviolet curable resin from adhering to the inner surface of the inner tube can also be exerted on the rear half side of the inner tube.
Therefore, according to the present invention, the continuous drawing time of the optical fiber can be extended as compared with the related art, and the optical fiber can be drawn efficiently.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first example of an embodiment of an ultraviolet curing device according to the present invention.

FIG. 2A is a plan view of a gas suction nozzle used in the first example, and FIG. 2B is a longitudinal sectional view of FIG.

FIG. 3 is a longitudinal sectional view of another example of the gas suction nozzle body used in the present invention.

FIG. 4 is a longitudinal sectional view of a conventional ultraviolet curing device.

FIG. 5 is an explanatory diagram of a gas flow flowing through a conventional ultraviolet curing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner tube 1a One opening 1b The other opening 2 UV curable resin coated optical fiber 3 UV light source 4 Mirror 5 Case 6 Inert gas blowing means 7 Anti-adhesion gas blowing means 8 Through-hole 9 Gas container 9a Inner chamber 9b Outside Chamber 10 Partition wall 11 Gas blowout hole 12 Gas supply port 13 Gas blowout nozzle 14 Through hole 15 Gas container 16 Gas supply port 17 Gas blowout nozzle body 17a Gas blowout hole 18 Inert gas suction means 19 Adhesion prevention gas suction means 20 Throughhole 21 Gas container 21a Inner chamber 21b Outer chamber 22 Partition wall 23 Gas suction hole 24 Gas exhaust port 25 Gas suction nozzle 26 Gas container 27 Gas suction nozzle body 28 Gas exhaust port 29 Disc body 30 Through hole 31 Gas suction hole

Claims (1)

[Claims] 1. An inner tube through which ultraviolet light passes, an ultraviolet light source for irradiating an ultraviolet curing resin-coated optical fiber passing along the center of the inner tube with ultraviolet light from outside the inner tube, and one of the inner tubes An inert gas blowing means for blowing an inert gas toward the center of the inner pipe at the opening side of the inner pipe, and an anti-adhesion gas flowing along the inner wall of the inner pipe at one opening side of the inner pipe. An ultraviolet curing device provided with an anti-adhesion gas blowing unit that blows out, wherein an inert gas suction unit that opens at the center of the opening on the other opening side of the inner tube and sucks the inert gas; An ultraviolet curing device, further comprising: an anti-adhesion gas suction unit that opens along the inner periphery of the inner tube on the other opening side of the inner tube and sucks the anti-adhesion gas.