JPH09156966A - Feeding of optical fiber coating resin and apparatus for feeding optical fiber coating resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for supplying resins to coating dies during the primary resin coating and the secondary resin coating on an optical fiber. SOLUTION: The first feeding path 21 and the second feeding path 22 are constructed in such a manner that the primary coating resin for an optical fiber can be fed at a determined rate by either of the first feeding path 21 or the second feeding path, which are interchangeable. When a foreign material is detected in the primary coating resin fed from the first feeding path 21, the feeding path 21 for the primary coating resin is changed to the second feeding path 22. Thus, the primary coating resin is fed from the second feeding path 22, and at the same time, the primary coating resin containing the foreign material and remaining in the first feeding path 21 is disposed. Further, when a foreign material is detected in the primary coating resin fed from the second feeding path 22, the feeding path for the primary coating resin is changed to the first feeding path 21. Thus, the primary coating resin is fed from the first feeding path 21, and the primary coating resin containing the foreign material and remaining in the second feeding path 22 is disposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating die for uniformly and stably coating an optical fiber preform on a surface of an optical fiber whose diameter has been reduced by heating and melting it in a heating furnace such as an electric furnace. The present invention relates to an optical fiber coating resin supply method and apparatus for supplying coating resin to an optical fiber.

[0002]

2. Description of the Related Art Optical fibers are manufactured by heating and melting an optical fiber preform in a heating furnace such as an electric furnace and drawing it out to make it smaller in diameter. Since there is a significant difference in the characteristics, a primary coating, a secondary coating, etc. are applied to improve the mechanical characteristics and ease of handling of the optical fiber core wire. The spinning of the optical fiber is performed by, for example, the optical fiber drawing device 1 as shown in FIG. 5 disclosed in Japanese Patent Laid-Open No. 1-166009. In this optical fiber drawing apparatus 1, a quartz glass-based optical fiber preform 2 is heated and melted in a heating furnace 3 or the like to form a pulling (referred to as drawing) optical fiber 4, which is cooled in a cooler 5. The heating furnace 3 is constituted by an electric furnace or the like, and the furnace is filled with an inert gas, and the optical fiber preform is heated and melted in the inert gas atmosphere. The cooler 5 is a cooler for primary coating that cools the optical fiber 4 drawn from the heating furnace 3 and spun into a predetermined wire diameter. For example, a low-temperature inert gas such as helium gas is blown onto the optical fiber 4. Is cooling.

In this cooler 5, the spun optical fiber 4 is cooled, but if it is left as it is, the surface is easily scratched and the mechanical strength is weak. Therefore, in the primary coating die 6, an acrylic acid salt or acrylic acid is used. ester,
An acrylate resin (UV curable resin) such as an acrylic acid resin is applied as a primary coating, and ultraviolet rays (heat is applied when the resin coated on the optical fiber 4 is a thermosetting resin) are irradiated with light in the curing furnace 8. The optical fiber 7 is obtained by curing the UV curable resin coated on the fiber 4. The primary coating resin is supplied to the primary coating die 6 from the resin tank 14 via the resin supply pipe line 13.
The supply of the primary coating resin from the resin tank 14 is performed by supplying air from the air supply port 15 into the resin tank 14.

The optical fiber 7 obtained by curing the UV curable resin coated on the surface of the optical fiber is cooled in the cooler 9. The cooler 9 is a cooler for secondary coating that cools the optical fiber 7 coated with the UV curable resin, and cools the optical fiber 7 by blowing a low temperature inert gas such as helium gas. In this cooler 9, the surface of the cooled optical fiber 7 is easily scratched and the mechanical strength is weak, so that the secondary coating die 1
At 0, a silicone resin or UV curable resin is applied as a secondary coating, and ultraviolet rays are irradiated in the curing furnace 11 to cure the UV curable resin coated on the optical fiber 7 to obtain the optical fiber core wire 12.

Like the primary coating die 6, the secondary coating die 10 is also adapted to be supplied with the primary coating resin from the resin tank 17 via the resin supply pipe 16. The supply of the primary coating resin from the resin tank 17 is performed by supplying air from the air supply port 18 into the resin tank 17.

[0006]

Thus, the optical fiber 4 spun into a predetermined wire diameter by the primary coating die 6 and the secondary coating die 10 is coated with resin (silicone resin) to protect it. The silicon resin coating of the optical fiber silicon resin wire is usually performed in one system with the connection tube from the primary coating resin storage tank to the primary coating die 6 and the connection tube from the secondary coating resin storage tank to the secondary coating die 10. I will not remove it while drawing. Therefore, when the primary coating die 6 is coated with the primary coating resin, and when the secondary coating die 10 is coated with the secondary coating resin, it is known that foreign matter, bubbles, etc. are mixed in the pressure-feeding coating resin. However, there is no way to remove foreign matter, bubbles, etc., resulting in coating as it is, which is also a cause of deterioration of product quality.

An object of the present invention is to remove foreign matters, bubbles and the like mixed in the pressure-feeding coating resin without stopping the drawing of the optical fiber, so that the optical fiber can be applied to the optical fiber during the primary resin coating and the secondary resin coating. It is to prevent coating and improve product quality.

[0008]

In the method for supplying an optical fiber coating resin according to the present invention, an optical fiber preform heated and melted in an inert gas atmosphere is spun to form an optical fiber having a predetermined diameter. For primary cooling,
This primary-cooled optical fiber is primary-coated with a heat- or ultraviolet-curable resin, and the coating resin of the optical fiber coated with this primary resin is cured with heat or ultraviolet rays to be secondary-cooled, and this secondary-cooled optical fiber is In a method for producing an optical fiber, wherein a coating resin is secondarily coated with a heat- or ultraviolet-curable resin, and the coating resin of the optical fiber coated with the secondary resin is cured by heat or ultraviolet rays. It is configured such that the coating resin can be supplied from the two supply paths of the first supply path and the second supply path by supplying a constant amount, and whether there is a foreign substance in the primary coating resin supplied from the first supply path. When the presence of foreign matter in the primary coating resin is detected, the supply path of the primary coating resin is switched to the second supply path, and the primary coating resin is supplied from the second supply path and the first coating resin is supplied. 1 The primary coating resin containing foreign matter in the supply route is discarded, and it is detected whether or not the foreign substance is present in the primary coating resin supplied from the second supply route, and the foreign substance is present in the primary coating resin. When the primary coating resin is detected, the supply route of the primary coating resin is switched to the first supply route, the primary coating resin is supplied from the first supply route, and the primary coating resin mixed with the foreign matter in the second supply route is detected. Discard the
Every time a foreign substance in the primary coating resin is detected, the supply path of the primary coating resin is alternately switched between the first supply path and the second supply path to supply the primary coating resin.

In the method of supplying the optical fiber coating resin according to the second aspect of the present invention, the secondary coating resin of the optical fiber is switched from two supply paths, a third supply path and a fourth supply path. When the presence of foreign matter in the secondary coating resin supplied from the third supply path is detected and the presence of foreign matter in the secondary coating resin is detected, The supply path of the next coating resin is switched to the fourth supply path, the secondary coating resin is supplied from the fourth supply path, and the secondary coating resin mixed with the foreign matter in the third supply path is discarded. Then, it is detected whether or not there is a foreign substance in the secondary coating resin supplied from the fourth supply route, and when it is detected that there is a foreign substance in the secondary coating resin, the supply route of the secondary coating resin is changed. Switching to the third supply path, the third supply path And the secondary coating resin containing the foreign matter in the fourth supply path are discarded, and the secondary coating resin supply path is opened every time the foreign matter in the secondary coating resin is detected. The third supply path and the fourth supply path are alternately switched to supply the secondary coating resin.

In the optical fiber coating resin supply device according to the third aspect of the present invention, the optical fiber preform is heated and melted in an inert gas atmosphere, an optical fiber having a predetermined diameter is drawn out, and the gas is cooled. A device for supplying a primary coating resin to a primary coating die for primary coating with a heat- or ultraviolet-curing resin, which is a resin that stores the primary coating resin and delivers a fixed amount of the primary coating resin by adjusting the air pressure with an automatic regulator. A tank; a first supply line connected to the resin tank and having an overflow valve; a first foreign matter detector attached to the first supply line; and an overflow valve connected to the resin tank A second supply line, a second foreign matter detector attached to the second supply line, the first supply line and the second supply line A three-way valve for switching between the first supply line and the second supply line, the one end being connected to the three-way valve, the other end being connected to the primary coating die, and the first supply pipe Inside the primary coating resin by means of a resin supply pipeline for supplying the primary coating resin supplied from a channel or the second supply pipeline to the primary coating die and the first foreign matter detector or the second foreign matter detector. When the presence of foreign matter is detected, the three-way valve is operated to switch the primary coating resin supply pipeline to the first supply pipeline or the second supply pipeline, and the overflow valve of the supply pipeline on the foreign matter detected side is detected. Is opened for a certain period of time and the automatic regulator is controlled to adjust the air pressure so that the primary coating resin supplied to the primary coating die has a constant amount.

According to a fourth aspect of the present invention, there is provided an optical fiber coating resin supplying device, wherein:
A flow rate measuring device for measuring the flow rate of the primary coating resin is provided, the measured flow rate value is taken into the control device, and the automatic regulator is adjusted so that the flow rate of the primary coating resin flowing in the resin supply pipe becomes a predetermined flow rate. Is controlled.

In the optical fiber coating resin supply device according to the fifth aspect of the present invention, the optical fiber preform is heated and melted in an inert gas atmosphere, and an optical fiber having a predetermined diameter is drawn out and gas cooled, A primary coating of a heat or UV curable resin, the primary coating resin of the optical fiber coated with this primary resin is cured by heat or UV rays and then secondary cooled, and then a thermal or UV curable resin is applied on the primary coating resin. A device for supplying a secondary coating resin to a secondary coating die for secondary coating of a resin tank, which stores the secondary coating resin and sends a fixed amount of the secondary coating resin by adjusting the air pressure by an automatic regulator. A third supply line connected to the resin tank and provided with an overflow valve, a first foreign matter detector attached to the third supply line, and the resin tank A fourth supply line connected with an overflow valve, a second foreign matter detector attached to the fourth supply line, connected to the third supply line and the fourth supply line And the third supply line and the fourth
Of the three-way valve for switching the supply pipeline, and one end of which is connected to the three-way valve, the other end of which is connected to the secondary coating die, and which is supplied from the third supply pipeline or the fourth supply pipeline. The three-way valve when the presence of foreign matter in the secondary coating resin is detected by the third foreign matter detector or the fourth foreign matter detector by a resin supply pipe for supplying the secondary coating resin coming to the secondary coating die. To switch the supply line of the secondary coating resin to the third supply line or the fourth supply line, open the overflow valve of the supply line on the side where the foreign matter is detected for a certain period of time, and control the automatic regulator. Then, a controller for adjusting the air pressure so that the secondary coating resin supplied to the secondary coating die has a constant amount.

In the optical fiber coating resin supply device according to the sixth aspect of the present invention, the resin supply pipe is provided with:
A flow rate measuring device for measuring the flow rate of the secondary coating resin is provided, and the measured flow rate value is taken into the control device so that the flow rate of the secondary coating resin flowing in the resin supply pipe becomes a predetermined flow rate. It is designed to control an automatic regulator.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of an optical fiber coating resin supply method and an optical fiber coating resin supply apparatus according to the present invention. In the figure, those denoted by the same reference numerals as those of the conventional example shown in FIG. 5 have the same members and the same functions. In the figure, 19 is a flow rate measuring device, which is provided in the resin supply pipeline 13 and measures the flow rate of the primary coating resin conveyed in the resin supply pipeline 13. Reference numeral 20 denotes a three-way valve, which is connected to the resin supply pipeline 13. The three-way valve 20 is connected to a first supply pipeline 21 and a second supply pipeline 22. This three-way valve 20
Is for switching the first supply pipeline 21 and the second supply pipeline 22 to connect to the resin supply pipeline 13.
Reference numeral 23 is a first foreign matter detector attached to the first supply pipeline 21, which detects foreign matter such as resin clumps and bubbles in the primary coating resin traveling in the first supply pipeline 21. In general, the presence or absence of foreign matter is detected from the laser that irradiates and transmits the laser. Reference numeral 24 denotes a second foreign matter detector attached to the second supply pipeline 22, and like the first foreign matter detector 23, a resin present in the primary coating resin traveling in the second supply pipeline 22. It detects foreign matter such as lumps and air bubbles, and generally detects the presence of foreign matter from a laser that irradiates and transmits a laser.

Reference numeral 25 is an overflow valve provided in the first supply pipeline 21, and there is a foreign matter in the primary coating resin traveling in the first supply pipeline 21 by the first foreign matter detector 23. This is a valve for discarding this foreign substance when the is detected. Reference numeral 26 is an overflow valve provided in the second supply line 22 and is used as a second foreign matter detector 24.
This is a valve for discarding foreign matter when it is detected that there is foreign matter in the primary coating resin traveling in the second supply pipe line 22.

Reference numeral 27 is an automatic regulator provided at the air supply port 15, and foreign matter is contained in the primary coating resin running in the supply path currently connected by the three-way valve 20, for example, the first supply pipeline 21. When the presence is detected, the three-way valve 20 is operated to switch the connection relationship with the resin supply pipeline 13 to the second supply pipeline 22, the overflow valve 25 is opened, and the inside of the first supply pipeline 21 is opened. When the primary coating resin containing the foreign matter is discarded, the pressure for supplying the primary coating resin to the second supply pipeline 22 decreases, so that the flow rate of the primary coating resin supplied to the second supply pipeline 22 decreases. This is for adjusting the air pressure to be supplied into the resin tank 14 so as to be maintained at a predetermined amount.

Reference numeral 28 denotes a control device, which is the first foreign matter detector 2
3. When the presence of foreign matter in the primary coating resin is detected by the second foreign matter detector 24, the three-way valve 20 is operated to change the supply channel of the primary coating resin to the first supply pipeline 21 or the second pipeline.
Of the primary coating resin to be supplied to the primary coating die 6 by controlling the automatic regulator 27 by opening the overflow valve 25 or the overflow valve 26 of the foreign material detection side of the supply pipeline for a certain period of time. The air pressure is adjusted so that

This resin supply line 13 and the flow rate measuring device 19
A three-way valve 20, a first supply line 21, a second supply line 22, a first foreign matter detector 23, a second foreign matter detector 24, an overflow valve 25, and an overflow valve. 26, the resin tank 14, and the air supply port 15
The automatic regulator 27 and the control device 28 constitute an optical fiber coating resin supply device 29.

The operation of the optical fiber coating resin supply device 29 thus constructed will be described with reference to the control flow of the control device 28 shown in FIGS. First, in step 30, the three-way valve 20 is operated to set it on the first supply conduit 21 side, and in step 31, the first foreign matter detector 23 is operated. When the production line is started in this state, the silica glass optical fiber preform 2 is heated and melted in the heating furnace 3 filled with the inert gas,
An optical fiber 4 having a predetermined diameter is obtained by drawing. The optical fiber 4 obtained by drawing is gas cooled in the primary cooler 5. The optical fiber 4 cooled in the primary cooler 5 is
In the primary coating die 6, an acrylate resin (UV curable resin) such as an acrylic acid salt, an acrylic acid ester or an acrylic acid resin is coated as a primary coating. The primary coating resin is supplied from the resin tank 14 through the first supply pipeline 21, through the three-way valve 20 and from the resin supply pipeline 13 to the primary coating die 6.

In step 32, the first supply line 2
It is detected whether or not there is a foreign substance in the primary coating resin flowing through 1. When it is detected in this step 32 that there is a foreign substance in the primary coating resin flowing through the first supply pipeline 21, in step 33 the three-way valve 20 is operated to supply the second supply from the side of the first supply pipeline 21. At the same time when the resin supply path is switched to the side of the conduit 22, the second foreign matter detector 24 is activated.

Then, in step 34, the overflow valve 25 is opened and the primary coating resin in the first supply line 21 is discarded. At this time, the overflow valve 2
When the valve 5 is opened, the pressure of the second supply pipe line 22 which is switched by operating the three-way valve 20 is lowered, so that the automatic regulator 27 is controlled to supply a constant amount of the primary coating resin to the primary coating die 6. I am trying to become. The primary coating resin to be discarded is the resin from the first foreign matter detector 23 to the overflow valve 25. By discarding this resin, the foreign matter mixed in the primary coating resin can be removed. If the time required to remove the foreign matter mixed in the primary coating resin is obtained in advance, it can be determined that the foreign matter has been removed by the passage of that time.

Therefore, in step 35, it is determined whether or not a predetermined time (the time required for removing the foreign matter mixed in the primary coating resin, which has been obtained in advance) has elapsed since the overflow valve 25 was opened. When it is determined in step 35 that the predetermined time has elapsed since the overflow valve 25 was opened, the overflow valve 25 of the first supply pipeline 21 is closed in step 36 shown in FIG.

Then, in step 37, it is detected whether or not there is a foreign substance in the primary coating resin flowing through the second supply conduit 22. When it is detected in this step 37 that there is a foreign substance in the primary coating resin flowing through the second supply pipeline 22, the three-way valve 20 is operated in step 38 to supply the first supply from the second supply pipeline 22 side. At the same time when the resin supply path is switched to the pipe 21 side, the first foreign matter detector 23 is activated.

Then, in step 40, the overflow valve 26 is opened and the primary coating resin in the second supply line 22 is discarded. The primary coating resin to be discarded is the resin from the second foreign matter detector 24 to the overflow valve 26. By discarding this resin, the foreign matter mixed in the primary coating resin can be removed. The time until the foreign matter mixed in the primary coating resin is removed is determined in advance from the speed of the primary coating resin flowing in the second supply pipeline 22 and the distance from the second foreign matter detector 24 to the overflow valve 26. Can be set.

Therefore, in step 40, it is judged whether or not a predetermined time (the time until the foreign matter mixed in the primary coating resin is removed from the inside of the second supply conduit 22) has elapsed since the overflow valve 26 was opened. To do. When it is determined in step 40 that the predetermined time has elapsed since the overflow valve 26 was opened, the overflow valve 26 of the second supply conduit 22 is closed in step 41 and the process returns to step 32 shown in FIG.

As described above, when the presence of foreign matter is detected in one of the supply pipelines while the primary coating resin is currently being supplied from the one supply pipeline to the resin supply pipeline, the other supply pipeline is detected. When switching to the supply of the primary coating resin from and operating, while supplying from the other supply pipeline to the resin supply pipeline,
When the presence of foreign matter is detected in the other supply pipeline, the supply of the primary coating resin is switched to the one supply pipeline, and when the presence of foreign matter is detected again in the one supply pipeline, the other supply pipeline is detected. By alternately switching the two supply pipelines to the passage, foreign matter mixed in the primary coating resin is prevented from being coated on the optical fiber 4.

FIG. 4 shows another embodiment of an optical fiber coating resin supply method and an optical fiber coating resin supply apparatus according to the present invention. In the figure, the same members as those in the embodiment shown in FIG.
They have the same function. In the figure, reference numeral 42 denotes a flow rate measuring device, which is provided in the resin supply pipeline 16 and measures the flow rate of the secondary coating resin conveyed in the resin supply pipeline 16. Reference numeral 43 is a three-way valve, which is a resin supply line 16
The three-way valve 43 is connected to a third supply line 44 and a fourth supply line 45. The three-way valve 43 is for connecting the resin supply pipeline 16 by switching between the third supply pipeline 44 and the fourth supply pipeline 45. 46 is the third attached to the third supply line 44
Is a foreign matter detector for detecting foreign matter such as resin clumps and bubbles in the secondary coating resin traveling in the third supply pipe line 44. The presence or absence of foreign matter is detected. 47 is the fourth
With a fourth foreign matter detector attached to the supply line 45 of
Similar to the third foreign matter detector 46, the third foreign matter detector 46 detects foreign matter such as resin clumps and bubbles in the secondary coating resin traveling in the fourth supply conduit 45.

Reference numeral 48 is an overflow valve provided in the third supply conduit 44, and foreign matter is present in the secondary coating resin traveling in the third supply conduit 44 by the third foreign matter detector 46. This is a valve for discarding this foreign substance when it is detected. 49 is an overflow valve provided in the fourth supply conduit 45, and a fourth foreign matter detector 47
This is a valve for discarding foreign matter when it is detected that there is foreign matter in the secondary coating resin traveling in the fourth supply conduit 45.

Reference numeral 50 denotes an automatic regulator provided in the air supply port 15, which is a supply path currently connected by the three-way valve 43, for example, a third foreign matter detector 46
When it is detected that there is a foreign substance in the secondary coating resin flowing in the supply pipeline 44, the three-way valve 43 is operated to connect the resin supply pipeline 16 and the third supply pipeline 44. Is switched to the connection relationship between the resin supply pipeline 16 and the fourth supply pipeline 45, the overflow valve 48 is opened, and the secondary coating resin containing the foreign matter in the third supply pipeline 44 is discarded. Since the pressure for supplying the secondary coating resin to the fourth supply pipeline 45 decreases, the resin tank is kept so that the flow rate of supplying the secondary coating resin to the fourth supply pipeline 45 is maintained at a predetermined amount. It is for adjusting the air pressure supplied to the inside of 14.

Reference numeral 51 is a control device, which is the third foreign matter detector 4
6. When the presence of foreign matter in the secondary coating resin is detected by the fourth foreign matter detector 47, the three-way valve 43 is operated to change the supply channel of the secondary coating resin to the first supply pipeline 21 or the above. Second
Of the secondary coating resin supplied to the primary coating die 6 by controlling the automatic regulator 50 by opening the overflow valve 48 or the overflow valve 49 of the supply pipeline on the side where the foreign matter is detected for a certain period of time. The air pressure is adjusted so that the amount becomes equal.

The resin supply pipe 16 and the flow rate measuring device 42
A three-way valve 43, a third supply line 44, a fourth supply line 45, a third foreign matter detector 46, a fourth foreign matter detector 47, an overflow valve 48, and an overflow valve. 49, resin tank 17, and air supply port 18
The automatic regulator 50 and the control device 51 constitute an optical fiber coating resin supply device 52.

The optical fiber coating resin supply device 52 thus constructed operates in the same manner as the optical fiber coating resin supply device 29.

[0033]

EFFECTS OF THE INVENTION According to the present invention, the foreign matter mixed in the pumping coating resin without stopping the drawing of the optical fiber
By removing bubbles and the like, it is possible to prevent the optical fiber from being coated during the primary resin coating and the secondary resin coating, and to improve the quality of the product.

[Brief description of the drawings]

FIG. 1 is a method for supplying an optical fiber coating resin according to the present invention,
FIG. 2 is an overall schematic diagram showing an embodiment of a supply device for an optical fiber coating resin.

FIG. 2 is a control flowchart of the control device shown in FIG.

FIG. 3 is a control flowchart of the control device shown in FIG.

FIG. 4 is a method for supplying an optical fiber coating resin according to the present invention,
FIG. 5 is an overall schematic diagram showing another embodiment of the optical fiber coating resin supply device.

FIG. 5 is an overall schematic diagram showing a conventional optical fiber drawing device.

[Explanation of symbols]

1 …………………………………………………… Optical fiber drawing device 2 ……………………………………………… Optical fiber preform 3 …… ………………………………………… Heating furnace 4 ……………………………………………… Optical fiber 5 ………………………… …………………… Cooler 6 ……………………………………………… Primary coating die 7 ……………………………………………… … Optical fiber 8 …………………………………………………… Curing furnace 9 ……………………………………………… Cooler 10 ………… ……………………………………… Secondary coating die 11 ……………………………………………… Curing furnace 12 …………………………………… …………… Optical fiber core wire 13 ………………………………………………… Resin supply line 14 ………………………………………………… Resin tank 15 ……………………………………………… Air supply port 16 ………………………… ………………………… Resin supply line 17 ……………………………………………… Resin tank 18 ……………………………………………… Air supply port 19 ……………………………………………… Flow rate measuring device 20 ……………………………………………… 3-way valve 21 ……………… …………………………………… First supply route 22 ……………………………………………… Second supply route 23 ……………………………… …………………… First foreign matter detector 24 ……………………………………………… Second foreign matter detector 25 …………………………………… ……………… Overflow valve 26 ……………………………………………… Overflow valve 27 ……………………………………………… Automatic regulator 28 ……………………………………………… Control unit 29 ……………………… …………………… Optical fiber coating resin supply device 42 ……………………………………………… Flowmeter 43 ……………………………………… ………… Three-way valve 44 ……………………………………………… 1st supply path 45 ……………………………………………… Second Supply path 46 …………………………………………………… 1st foreign matter detector 47 ………………………………………………… Second foreign matter detector 48 ………………………………………………… Overflow valve 49 …………………………………………… Overflow valve 50 ……………………… …………………… Automatic regulator 51 …………………… ........................... controller 52 supply apparatus ................................................... optical fiber coating resin

Claims (6)

[Claims] 1. An optical fiber preform that is heated and melted in an inert gas atmosphere is spun to draw out an optical fiber of a predetermined diameter and is primarily cooled, and a heat- or UV-curable resin is primarily applied to the primary-cooled optical fiber. The primary resin coated optical fiber coating resin is cured with heat or ultraviolet rays to be secondarily cooled, and the secondary cooled optical fiber coating resin is secondarily coated with a heat or ultraviolet ray curable resin. Then, in the optical fiber manufacturing method in which the coating resin of the optical fiber coated with the secondary resin is cured by heat or ultraviolet rays, the primary coating resin of the optical fiber is divided into a first supply path and a second supply path. It is configured so that a fixed amount can be supplied by switching from the supply path, and whether or not there is a foreign matter in the primary coating resin supplied from the first supply path is detected, and the presence of a foreign matter in the primary coating resin is detected. Then, the supply path of the primary coating resin is switched to the second supply path, the primary coating resin is supplied from the second supply path, and the primary coating resin mixed with foreign matter in the first supply path is discarded. Then, if it is detected whether or not there is a foreign matter in the primary coating resin supplied from the second supply path, and if there is a foreign matter in the primary coating resin, the supply path of the primary coating resin is set to the first Each time the primary coating resin in the second supply path is discarded and the primary coating resin in the second supply path is discarded, and the foreign material in the primary coating resin is detected. A method for supplying an optical fiber coating resin, characterized in that the primary coating resin is supplied by alternately switching the supply path of the primary coating resin between the first supply path and the second supply path. 2. The secondary coating resin for the optical fiber is configured so that a fixed amount can be supplied by switching from two supply paths, a third supply path and a fourth supply path, and is supplied from the third supply path. The presence of foreign matter in the secondary coating resin is detected, and when the presence of foreign matter in the secondary coating resin is detected, the supply path of the secondary coating resin is switched to the fourth supply path, and In the secondary coating resin supplied from the fourth supply path, the secondary coating resin supplied from the fourth supply path is discarded, and the secondary coating resin mixed with the foreign matter in the third supply path is discarded. When it is detected that there is a foreign substance in the secondary coating resin and when there is a foreign substance in the secondary coating resin, the supply route of the secondary coating resin is switched to the third supply route, and the While supplying the next coating resin, the foreign matter in the fourth supply path is mixed. The secondary coating resin is discarded by discarding the entered secondary coating resin and switching the supply route of the secondary coating resin between the third supply route and the fourth supply route alternately every time a foreign substance in the secondary coating resin is detected. The method for supplying an optical fiber coating resin according to claim 1, wherein the supply of the optical fiber coating resin is performed. 3. An optical fiber preform is heated and melted in an inert gas atmosphere, an optical fiber having a predetermined diameter is drawn out and gas cooled, and then a primary coating die for primary coating with a thermosetting or ultraviolet curable resin is primary coated. A device for supplying a resin, comprising a resin tank for storing a primary coating resin and delivering a constant amount of the primary coating resin by adjusting an air pressure by an automatic regulator, and a first tank equipped with an overflow valve connected to the resin tank. A supply line, a first foreign matter detector attached to the first supply line, a second supply line connected to the resin tank and provided with an overflow valve, and a second supply line. Second attached
Foreign matter detector, a three-way valve connected to the first supply line and the second supply line to switch between the first supply line and the second supply line, and one end of the three-way valve And the other end is connected to the primary coating die, and a resin supply pipeline for supplying the primary coating resin supplied from the first supply pipeline or the second supply pipeline to the primary coating die. And the first foreign matter detector or the second
When the presence of foreign matter in the primary coating resin is detected by the foreign matter detector, the three-way valve is operated to switch the supply channel of the primary coating resin to the first supply pipeline or the second supply pipeline.
A control device that opens the overflow valve of the supply pipe on the foreign substance detection side for a certain period of time and controls the automatic regulator to adjust the air pressure so that the primary coating resin supplied to the primary coating die has a constant amount. An optical fiber coating resin supply device characterized by the above. 4. A primary coating resin flowing in the resin supply pipe, wherein a flow rate measuring device for measuring a flow rate of the primary coating resin is provided in the resin supply pipe, and the measured flow rate value is taken into the control device. 4. The automatic regulator is controlled so that the flow rate of the predetermined amount becomes a predetermined flow rate.
The optical fiber coating resin supply device described. 5. An optical fiber preform is heated and melted in an inert gas atmosphere, an optical fiber having a predetermined diameter is drawn out and cooled with gas, and then a heat or ultraviolet curable resin is primarily coated, and this primary resin coating is performed. After the primary coating resin of the optical fiber is cured by heat or ultraviolet rays and secondarily cooled, the secondary coating resin is supplied to the secondary coating die that secondarily coats the primary coating resin with the heat or ultraviolet curing resin. A third supply pipe having a resin tank for storing a secondary coating resin and delivering a fixed amount of the secondary coating resin by adjusting an air pressure by an automatic regulator, and an overflow valve connected to the resin tank Line, a first foreign matter detector attached to the third supply line, a fourth supply line equipped with an overflow valve connected to the resin tank, and the fourth supply line. A second foreign matter detector attached to the supply line, and a three-way switch connected between the third supply line and the fourth supply line to switch between the third supply line and the fourth supply line. A valve, one end of which is connected to the three-way valve and the other end of which is connected to the secondary coating die, and the secondary coating resin supplied from the third supply pipe line or the fourth supply pipe line is added. When the presence of foreign matter in the secondary coating resin is detected by the resin supply pipe for supplying the secondary coating die and the third foreign matter detector or the fourth foreign matter detector, the three-way valve is operated to perform the secondary coating. The resin supply pipeline is switched to the third supply pipeline or the fourth supply pipeline, and the overflow valve of the supply pipeline on the foreign object detection side is opened for a certain period of time.
A controller for controlling an automatic regulator to adjust air pressure so that the secondary coating resin supplied to the secondary coating die has a constant amount, and an optical fiber coating resin supply device. 6. A flow meter for measuring the flow rate of the secondary coating resin is provided in the resin supply conduit, the measured flow rate value is taken into the control device, and the secondary flowing in the resin supply conduit is provided. 6. The automatic regulator is controlled so that the flow rate of the coating resin becomes a predetermined flow rate.
The optical fiber coating resin supply device described.