Resin supply device for optical fiber and method for manufacturing optical fiber

Abstract

To make it easy to keep a temperature of a resin in a piping constant so as to improve a yield and a production efficiency, even during a production time of optical fibers, during production stop of the optical fibers, and during a time from the production stop and production start of the optical fiber.SOLUTION: A resin feeder for optical fibers comprises a first tank for feeding a resin to a resin-coated die for an optical fiber through a resin feeding pipe, and a second tank for supplementing the resin to the first tank through a resin replenishment pipe, and supplies the resin to the resin-coated die. The resin feeding pipe includes a pipe branch portion, a circulation resin pipe for returning the resin from the pipe branch portion to the second tank, a first valve provided between the pipe branch portion and the resin-coated die, and a second valve provided in the circulation resin pipe.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an optical fiber resin supplying device and an optical fiber manufacturing method. [Background technology]

[0002] Patent Document 1 discloses an optical fiber resin supplying device that supplies resin to a resin-coating die for optical fiber, the device comprising a first tank that supplies resin to the resin-coating die through a resin supply pipe, and a second tank that supplies resin to the first tank through a resin refill pipe, and is provided with a circulating resin pipe that returns resin to the second tank from a connection point of the resin supply pipe to the resin-coating die. The optical fiber resin supplying device disclosed in Patent Document 1 uses a piping whose connection destination can be changed, and connects the piping to the resin-coating die during optical fiber production, and changes the connection destination so that the piping becomes part of the circulating resin pipe when optical fiber production is stopped.

[0003] Patent Document 2 discloses a method for manufacturing an optical fiber, which includes a resin coating step of supplying resin to a resin coating section through a pipe, and passing a glass fiber or a coated fiber through the resin coating section to coat the resin on the outer periphery of the glass fiber or the coated fiber, in which, in the resin coating step, a fluid at a constant temperature is caused to flow around the resin coating section to keep the temperature of the resin coating section constant, and a heating section provided on the outer periphery of at least a portion of the pipe is controlled so that the resin temperature in the pipe becomes a target temperature. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-209370 A [Patent Document 2] JP 2018-48050 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the optical fiber resin supplying device described in Patent Document 1 and the optical fiber manufacturing method described in Patent Document 2, the flow of resin in the piping stops at least during the period from when the optical fiber manufacturing is stopped to when the optical fiber manufacturing is enabled, making it difficult to keep the temperature of the resin in the piping constant. Therefore, when starting to coat the glass fiber, the temperature of the resin provided to the resin coating die 40 is not appropriate, leading to a decrease in yield and a decrease in production efficiency.

[0006] An object of the present disclosure is to provide an optical fiber resin supply device and an optical fiber manufacturing method that can easily maintain the temperature of resin in piping constant during optical fiber manufacturing, when optical fiber manufacturing is stopped, and during the period from the stop of optical fiber manufacturing to the start of optical fiber manufacturing, thereby improving yield and production efficiency. [Means for solving the problem]

[0007] An optical fiber resin supplying device according to one aspect of the present disclosure includes: An optical fiber resin supplying device for supplying resin to a resin-coating die for an optical fiber, the device comprising: a first tank for supplying resin to the resin-coating die through a resin supply pipe; and a second tank for supplying resin to the first tank through a resin supply pipe, the device supplying resin to the resin-coating die, The resin supply pipe is A piping branch portion; a circulating resin pipe that returns resin from the pipe branch to the second tank; A first valve provided between the pipe branching portion and the resin-coated die; and a second valve provided in the circulation resin pipe.

[0008] A method for producing an optical fiber according to one aspect of the present disclosure includes the steps of: 1. A method for manufacturing an optical fiber, comprising: coating a glass fiber with an optical fiber resin supplied from an optical fiber resin supply device; and curing the coated optical fiber resin to manufacture an optical fiber, comprising the steps of: The optical fiber resin supply device includes: The apparatus includes a first tank that supplies resin to a resin coating die for an optical fiber through a resin supply pipe, and a second tank that supplies resin to the first tank through a resin supply pipe, The resin supply pipe is a piping branching section, a circulating resin piping for returning resin from the piping branching section to the second tank, a first valve provided between the piping branching section and the resin-coated die, and a second valve provided on the circulating resin piping, When manufacturing an optical fiber, the first valve is opened and the second valve is closed to control the resin temperature in the resin supply pipe to a target temperature; When no optical fiber is to be manufactured, the first valve is closed and the second valve is opened to control the resin temperature in the resin supply pipe to a target temperature. Effect of the Invention

[0009] According to the configuration disclosed above, it is easy to keep the temperature of the resin in the piping constant during the production of the optical fiber, when the production of the optical fiber is stopped, and during the period from the stop of the production of the optical fiber to the start of the production, thereby making it possible to improve yield and production efficiency. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing an optical fiber resin supplying device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described. An optical fiber resin supplying device according to one aspect of the present disclosure includes: An optical fiber resin supplying device for supplying resin to a resin-coating die for an optical fiber, the device comprising: a first tank for supplying resin to the resin-coating die through a resin supply pipe; and a second tank for supplying resin to the first tank through a resin supply pipe, the device supplying resin to the resin-coating die, The resin supply pipe is A piping branch portion; a circulating resin pipe that returns resin from the pipe branch to the second tank; A first valve provided between the pipe branching portion and the resin-coated die; and a second valve provided in the circulation resin pipe. With this configuration, the flow of resin in the piping can be maintained during the production of the optical fiber, when production of the optical fiber is stopped, and during the period from the stop of production of the optical fiber to the start of production. This makes it easier to keep the temperature of the resin in the piping constant, and the resin temperature can be maintained within a range suitable for the production of optical fiber, thereby improving yield and production efficiency.

[0012] In the optical fiber resin supplying device, The first valve and the second valve are preferably pinch valves. A pinch valve is a valve that blocks the inside of a tube through which resin flows by pressing and pinching the tube from the outside, and does not open or close the tube by providing a member inside the tube. Therefore, with this configuration, for example, it is less likely that resin will adhere to the inside of the tube and solidify, so it is possible to prevent situations in which part of the solidified resin flows into the resin coating die and gets mixed into the coating of the optical fiber, or the flow rate of resin passing through the part where the valve is installed decreases over time. In addition, maintenance is made easier and the frequency of maintenance can be reduced.

[0013] The optical fiber resin supply device includes: a temperature control unit that keeps the temperature of the resin-coated die constant by flowing a fluid at a constant temperature around the resin-coated die; a heating unit that heats an outer periphery of at least a part of the resin supply pipe between the first tank and the pipe branching portion; a temperature measuring unit for measuring a resin temperature in the resin supply pipe between the heating unit and the pipe branching unit; A control unit that controls the heating unit so that the resin temperature measured by the temperature measuring unit becomes a target temperature; It is preferable that the compound further comprises: According to this configuration, since the resin temperature in the resin supply pipe is measured, the temperature can be controlled with higher accuracy. In addition, even when the optical fiber is not being manufactured, the resin flow can be maintained, and the resin temperature can be maintained in a range suitable for manufacturing the optical fiber with higher accuracy.

[0014] The optical fiber resin supply device includes: In the circulating resin pipe, a flow rate adjusting pinch valve; It is preferable that the compound further comprises: According to this configuration, the flow rate of the resin returning to the second tank can be adjusted in the same manner as the flow rate of the resin supply pipe 20 during the manufacture of the optical fiber, for example, so that it becomes easy to maintain the resin temperature constant when the manufacture of the optical fiber is stopped.

[0015] The optical fiber resin supply device includes: In the circulating resin pipe, a flow rate measuring device and It is preferable that the compound further comprises: According to this configuration, by measuring the flow rate of the resin returning to the second tank, for example, it becomes possible to control the flow rate of the resin returning to the second tank with higher accuracy.

[0016] A method for producing an optical fiber according to one aspect of the present disclosure includes the steps of: 1. A method for manufacturing an optical fiber, comprising: coating a glass fiber with an optical fiber resin supplied from an optical fiber resin supply device; and curing the coated optical fiber resin to manufacture an optical fiber, comprising the steps of: The optical fiber resin supply device includes: The apparatus includes a first tank that supplies resin to a resin coating die for an optical fiber through a resin supply pipe, and a second tank that supplies resin to the first tank through a resin supply pipe, The resin supply pipe is a piping branching section, a circulating resin piping for returning resin from the piping branching section to the second tank, a first valve provided between the piping branching section and the resin-coated die, and a second valve provided on the circulating resin piping, When manufacturing an optical fiber, the first valve is opened and the second valve is closed to control the resin temperature in the resin supply pipe to a target temperature; When no optical fiber is to be manufactured, the first valve is closed and the second valve is opened to control the resin temperature in the resin supply pipe to a target temperature. With this configuration, the flow of resin in the piping can be maintained during the production of the optical fiber, when production of the optical fiber is stopped, and during the period from the stop of production of the optical fiber to the start of production. This makes it easier to keep the temperature of the resin in the piping constant, and the resin temperature can be maintained within a range suitable for the production of optical fiber, thereby improving yield and production efficiency.

[0017] [Details of the embodiment of the present disclosure] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, examples of embodiments of an optical fiber resin supplying device and an optical fiber manufacturing method according to the present disclosure will be described with reference to the drawings.

[0018] (Optical fiber resin supply device) First, an optical fiber resin supplying device according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an optical fiber resin supplying device 1 (hereinafter also referred to as "supplying device 1") according to an embodiment of the present disclosure. The supplying device 1 includes a first tank 11, a second tank 13, a resin refill pipe 15, a resin supply pipe 20, a temperature adjustment unit 31, a heating unit 32, a temperature measurement unit 33, and a control unit 34. The resin supply pipe 20 includes a pipe branching unit 21, a first valve 22, a circulating resin pipe 23, a second valve 24, a third valve 25, and a flow rate measuring device 26.

[0019] The second tank 13 is a sub-tank that supplies resin to the first tank 11. Liquid resin is stored inside the second tank 13. The resin in the second tank 13 can be heated by a second tank heater 14 provided on at least a part of the outer periphery of the second tank 13. The resin in the second tank 13 is pressurized by, for example, high-pressure nitrogen gas or the like, and is sent to the first tank 11 through a resin supply pipe 15 that connects the second tank 13 and the first tank 11.

[0020] The first tank 11 is a main tank that supplies resin to the resin-coating die 40. The first tank 11 stores the same liquid resin as that stored in the second tank 13. The resin in the first tank 11 can be heated by a first tank heater 12 provided on at least a portion of the outer periphery of the first tank 11. The resin in the first tank 11 is pressurized, for example, by high-pressure nitrogen gas or the like, and is sent to the resin-coating die 40 via a resin supply pipe 20 connected to the first tank 11.

[0021] The heating unit 32 heats at least a part of the outer periphery of the resin supply pipe 20 between the first tank 11 and the pipe branching unit 21. The heating unit 32 is, for example, a tape heater wrapped around the outer periphery of the resin supply pipe 20. Note that the resin supply pipe 15 and the circulating resin pipe 23 may also be provided with a tape heater or the like for heating the resin in the pipes.

[0022] The temperature measuring unit 33 measures the resin temperature in the resin supply pipe 20 between the heating unit 32 and the pipe branching unit 21. The temperature measuring unit 33 is preferably a thermocouple provided in the resin supply pipe 20. The resin temperature measured by the temperature measuring unit 33 is transmitted to the control unit 34, for example.

[0023] The control unit 34 controls the heating unit 32 so that the resin temperature measured by the temperature measuring unit 33 becomes the target temperature. The control unit 34 indirectly adjusts the resin temperature in the resin coating die 40 and / or the resin temperature in the circulation resin pipe 23 by making the resin temperature measured by the temperature measuring unit 33 become the target temperature. The target temperature can be appropriately determined depending on the type of resin used for coating, the desired coating diameter, etc. Note that the resin temperature is a value correlated with the resin viscosity, and the higher the resin temperature, the smaller the resin viscosity becomes. Therefore, between the case where the desired diameter is thick and the case where the desired diameter is thin, the target temperature is higher in the case where the desired diameter is thin.

[0024] Furthermore, since the resin temperature is a value correlated with the resin viscosity as described above, a viscosity measuring meter that measures the resin viscosity in the resin supply pipe 20 may be provided instead of the temperature measuring unit 33, and the heating unit 32 may be controlled based on the measured viscosity. From a similar viewpoint, a flow measuring meter that measures the flow rate of the resin in the resin supply pipe 20 may be provided instead of or in addition to the temperature measuring unit 33, and the degree of heating by the heating unit 32 or the degree of opening or closing of at least one of the first valve 22, the second valve 24, and the third valve 25 may be controlled based on the measured flow rate. As the flow measuring meter, one similar to the flow measuring instrument 26 described later may be used.

[0025] The position of the temperature measuring unit 33 is preferably close to the resin-coating die 40, for example, from the viewpoint of making it easier to adjust the resin temperature in the resin-coating die 40. That is, the position of the temperature measuring unit 33 is preferably close to the pipe branching portion 21. From the same viewpoint as above, the position of the pipe branching portion 21 is also preferably close to the resin-coating die 40.

[0026] In the resin supply pipe 20, a first valve 22 is provided on a path from the pipe branching section 21 to the resin-coated die 40. The first valve 22 is preferably located near the pipe branching section 21. When the first valve 22 is open, all or a part of the liquid resin heated by the heating section 32 is supplied to the resin-coated die 40. The temperature adjustment section 31 is provided around the resin-coated die 40. The temperature adjustment section 31 suppresses fluctuations in the resin temperature by, for example, flowing a fluid at a constant temperature around the resin-coated die 40 to keep the temperature of the resin-coated die 40 constant.

[0027] The resin-coating die 40 stores liquid resin supplied through the resin supply pipe 20. A glass fiber 41 formed by drawing an optical fiber preform passes through the resin-coating die 40, so that resin is applied to the outer periphery of the glass fiber 41. The applied resin is cured by ultraviolet light irradiated from an ultraviolet irradiation device (not shown) as necessary to become a coated glass fiber 42. The coated glass fiber 42 can become an optical fiber to be a product. The coated glass fiber 42 may have two or more coating layers. When the coating layer is two or more, the resin-coating die 40 may be a die capable of simultaneously applying two or more layers, or another resin-coating die and a supply device 1 may be provided downstream of the resin-coating die 40.

[0028] In the resin supply pipe 20, a path connecting the pipe branching portion 21 to the second tank 13 becomes a circulation resin pipe 23 for returning the resin to the second tank 13. A second valve 24 is provided in the circulation resin pipe 23. The second valve 24 is preferably located close to the pipe branching portion 21. When the second valve 24 is open, all or a part of the liquid resin heated by the heating unit 32 is transferred to the second tank 13 through the circulation resin pipe 23.

[0029] The first valve 22 and the second valve 24 are controlled to open and close based on, for example, a signal transmitted from the control unit 34. The first valve 22 and the second valve 24 are preferably, for example, pinch valves. A pinch valve is a valve that can block the flow inside a flexible tube by pinching the tube. When a pinch valve is used, at least a part of the path through which the resin flows is formed by a flexible material.

[0030] A third valve 25 is provided downstream of the second valve 24 in the circulation resin pipe 23. The degree of opening and closing of the third valve 25 is controlled, for example, based on a signal transmitted from the control unit 34. The third valve 25 is a valve for adjusting the flow rate of the resin, and is preferably a pinch valve capable of adjusting the flow rate. The pinch valve capable of adjusting the flow rate is, for example, a pinch valve capable of adjusting the amount of pressing of a flexible tube.

[0031] The first valve 22 and the second valve 24 may also be pinch valves capable of adjusting the flow rate. When the second valve 24 is a pinch valve capable of adjusting the flow rate, the flow rate of the resin in the circulation resin pipe 23 can be adjusted by the second valve 24, so that the third valve 25 does not need to be provided.

[0032] A flow rate measuring device 26 is provided downstream of the third valve 25 in the circulating resin pipe 23. The flow rate measuring device 26 is preferably one that can measure the flow rate of the resin without the sensor part coming into contact with the resin, and specifically, is preferably a clamp-on type ultrasonic flow meter that can be attached to the outside of the pipe for use.

[0033] The flow rate measured by the flow rate measuring instrument 26 is transmitted to, for example, the control unit 34. The control unit 34 controls the degree of opening and closing of the third valve 25 so that the flow rate of the resin measured by the flow rate measuring instrument 26 becomes a desired value. The desired value is, for example, a preferred flow rate of the resin flowing through the resin supply pipe 20 in the case of producing the coated glass fiber 42 with the first valve 22 open and the second valve 24 closed.

[0034] (Optical fiber manufacturing method) The method for manufacturing an optical fiber according to this embodiment will be described below with reference to Fig. 1. The method for manufacturing an optical fiber according to this embodiment is a method for manufacturing an optical fiber (coated glass fiber 42) by coating a glass fiber 41 with a resin for optical fiber supplied from an optical fiber resin supplying device 1 and curing the coated resin.

[0035] In the manufacturing method according to this embodiment, when an optical fiber is manufactured, the supply device 1 operates in a first mode, which will be described later, and when an optical fiber is not manufactured, the supply device 1 operates in a second mode, which will be described later. When an optical fiber is not manufactured, for example, supply of the glass fiber 41 to the resin-coated die 40 is stopped. In the manufacturing method according to this embodiment, the first mode and the second mode are alternately repeated.

[0036] In the first mode, the resin transferred from the first tank 11 is heated by the heating unit 32. The degree of heating by the heating unit 32 is controlled by the control unit 34 so that the resin temperature measured by the temperature measuring unit 33 becomes the target temperature. As described above, when a viscosity measuring meter or a flow measuring meter is used instead of or in addition to the temperature measuring unit 33, the heating unit 32 may be controlled so that the measured resin viscosity or resin flow rate becomes the target value.

[0037] In the first mode, resin is supplied to the resin-coating die 40. In the first mode, for example, the first valve 22 is controlled to be opened and the second valve 24 is controlled to be closed. When controlled in this manner, the resin heated by the heating unit 32 does not proceed downstream of the second valve 24, but is supplied to the resin-coating die 40 and used to coat the glass fiber 41.

[0038] Note that, even in the first mode, the second valve 24 may be opened for the purpose of controlling the flow rate of the resin supplied to the resin-coating die 40. When the second valve 24 is opened, it is preferable to control the degree of opening / closing of the second valve 24 so that the flow rate of the resin flowing downstream of the second valve 24 is less than the flow rate of the resin flowing downstream of the first valve 22. It is preferable that the control of the degree of opening / closing of the second valve 24 in the first mode is performed based on, for example, the line speed of the glass fiber 41 or the coated glass fiber 42.

[0039] In the second mode, as in the first mode, the resin transferred from the first tank 11 is heated by the heating unit 32. The degree of heating by the heating unit 32 is controlled by the control unit 34 so that the resin temperature measured by the temperature measuring unit 33 becomes the target temperature. As described above, when a viscosity measuring meter or a flow measuring meter is used instead of or in addition to the temperature measuring unit 33, the heating unit 32 may be controlled so that the measured resin viscosity or resin flow rate becomes the target value.

[0040] On the other hand, in the second mode, the supply of resin to the resin-coating die 40 is stopped. That is, in the second mode, the first valve 22 is controlled to be closed and the second valve 24 is controlled to be opened. Therefore, the resin heated by the heating unit 32 does not proceed downstream of the first valve 22, but returns to the second tank 13 via the circulation resin pipe 23.

[0041] In the second mode, it is preferable to control the degree of opening and closing of the third valve 25 based on the flow rate of the resin measured by the flow rate measuring instrument 26. That is, in the second mode, it is preferable to control the flow rate of the resin in the circulation resin pipe 23.

[0042] In the optical fiber manufacturing method according to this embodiment, even in the second mode in which no optical fiber is manufactured, resin continues to flow through the resin supply pipe 20. Moreover, the resin that continues to flow through the resin supply pipe 20 is controlled to have a temperature, etc. suitable for being supplied to the resin-coated die 40. Therefore, even immediately after switching to the first mode in order to manufacture an optical fiber, the temperature, etc. of the resin flowing through the resin supply pipe 20 remains at a temperature, etc. suitable for being supplied to the resin-coated die 40.

[0043] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. Furthermore, the number, position, shape, etc. of the components described above are not limited to the above embodiments, and can be changed to the number, position, shape, etc. that are suitable for implementing the present invention. [Explanation of symbols]

[0044] 1: Optical fiber resin supply device (supply device) 11: First Tank 12: First tank heater 13: Second Tank 14: Second tank heater 15: Resin supply piping 20: Resin supply piping 21: Pipe branch section 22: First valve 23:Resin piping for circulation 24: 2nd valve 25: 3rd valve 26:Flow rate measuring device 31: Temperature control section 32: Heating part 33:Temperature measurement part 34: Control unit 40: Resin-coated die 41: Glass fiber 42: Coated glass fiber

Claims

1. An optical fiber resin supplying device for supplying resin to a resin-coating die for an optical fiber, comprising: a first tank for supplying resin to the resin-coating die through a resin supply pipe; and a second tank for replenishing resin to the first tank through a resin replenishing pipe, the device comprising: The resin supply pipe is A piping branch portion; a circulating resin pipe that returns resin from the pipe branch to the second tank; A first valve provided between the pipe branching portion and the resin-coated die; A second valve provided in the circulating resin pipe. Resin supply device for optical fiber.

2. the first valve and the second valve are pinch valves; 2. The optical fiber resin supplying device according to claim 1.

3. a temperature control unit that keeps the temperature of the resin-coated die constant by flowing a fluid at a constant temperature around the resin-coated die; a heating unit configured to heat an outer periphery of at least a portion of the resin supply pipe between the first tank and the pipe branching portion; a temperature measuring unit for measuring a resin temperature in the resin supply pipe between the heating unit and the pipe branching unit; A control unit that controls the heating unit so that the resin temperature measured by the temperature measuring unit becomes a target temperature; 3. The optical fiber resin supplying device according to claim 1, further comprising:

4. In the circulating resin pipe, a flow rate adjusting pinch valve; The optical fiber resin supplying device according to claim 1 , further comprising:

5. In the circulating resin pipe, a flow rate measuring device and The optical fiber resin supplying device according to claim 4, further comprising:

6. 1. A method for manufacturing an optical fiber, comprising: coating a glass fiber with an optical fiber resin supplied from an optical fiber resin supply device; and curing the coated optical fiber resin to manufacture an optical fiber, comprising the steps of: The optical fiber resin supply device includes: The present invention includes a first tank that supplies resin to a resin coating die for an optical fiber through a resin supply pipe, and a second tank that supplies resin to the first tank through a resin supply pipe, The resin supply pipe is a piping branching section, a circulating resin piping for returning resin from the piping branching section to the second tank, a first valve provided between the piping branching section and the resin-coated die, and a second valve provided on the circulating resin piping, When manufacturing an optical fiber, the first valve is opened and the second valve is closed to control the resin temperature in the resin supply pipe to a target temperature; When no optical fiber is to be manufactured, the first valve is closed and the second valve is opened, and the resin temperature in the resin supply pipe is controlled to be a target temperature. A method for manufacturing optical fiber.

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