Apparatus and method for manufacturing optical fiber

Abstract

To provide an apparatus and method for manufacturing an optical fiber, which suppresses an inflow of air into a cooling apparatus for cooling using a hydrogen gas.SOLUTION: An apparatus for manufacturing an optical fiber includes: a drawing furnace for heating and melting a base material of an optical fiber and drawing it into a wire; a cooling device for cooling the drawn glass fiber; a reserve chamber provided at an upper end of the cooling device; a hydrogen gas supply device for supplying a hydrogen gas into the cooling device; and an inert gas supply device for supplying an inert gas into the reserve chamber.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Documents 1 and 2 disclose optical fiber drawing devices in which a glass fiber drawn from a drawing furnace is cooled by a cooling device supplied with helium (He) gas.

[0003] Patent Document 3 discloses an optical fiber drawing apparatus in which a glass fiber drawn from a drawing furnace is cooled by a cooling device to which hydrogen gas is supplied. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-103649 A [Patent Document 2] JP 2005-119901 A [Patent Document 3] Japanese Patent Application Publication No. 6-157065 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, in optical fiber manufacturing equipment, the use of hydrogen gas, which is easy to obtain and has high thermal conductivity, instead of helium gas as an inert gas for cooling glass fibers is being considered. However, hydrogen gas is flammable, and the explosive concentration range of hydrogen in the atmosphere is 4 to 75%, so explosion-proof measures are required.

[0006] An object of the present disclosure is to provide an optical fiber manufacturing apparatus and method that suppresses the inflow of air into a cooling device that uses hydrogen gas for cooling. [Means for solving the problem]

[0007] The optical fiber manufacturing apparatus of the present disclosure comprises: a drawing furnace for heating and melting the optical fiber preform and drawing it; a cooling device for cooling the drawn glass fiber; A spare chamber provided at an upper end of the cooling device; a hydrogen gas supply device for supplying hydrogen gas into the cooling device; an inert gas supply device for supplying an inert gas into the preliminary chamber; It is equipped with: Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an optical fiber manufacturing apparatus and method that suppresses the inflow of air into a cooling device that uses hydrogen gas for cooling. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of an optical fiber manufacturing apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing an example of the configuration of the auxiliary chamber and the cooling device of the optical fiber manufacturing apparatus of FIG. [Diagram 3] FIG. 3 is a schematic diagram showing a configuration example of a preliminary chamber and a cooling device of an optical fiber manufacturing apparatus according to the first modification. [Figure 4] FIG. 4 is a schematic diagram showing a configuration example of a preliminary chamber and a cooling device of an optical fiber manufacturing apparatus according to the second modification. [Diagram 5] FIG. 5 is a schematic diagram showing a configuration example of a preliminary chamber and a cooling device of an optical fiber manufacturing apparatus according to the third modification. [Figure 6] FIG. 6 is a conceptual diagram showing the configuration of an optical fiber manufacturing apparatus according to the second embodiment. [Figure 7] FIG. 7 is a schematic diagram showing a configuration example of a cooling device of the optical fiber manufacturing apparatus of FIG. [Figure 8] FIG. 8 is a schematic diagram showing a configuration example of a preliminary chamber and a cooling device of an optical fiber manufacturing apparatus according to the fourth modification. [Figure 9] FIG. 9 is a schematic diagram showing a configuration example of a preliminary chamber and a cooling device of an optical fiber manufacturing apparatus according to the fifth modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Description of the embodiments of the present disclosure] First, the contents of the embodiments of the present disclosure will be listed and described. The optical fiber manufacturing apparatus of the present disclosure comprises: (1) a drawing furnace for heating and melting an optical fiber preform and drawing it; a cooling device for cooling the drawn glass fiber; A spare chamber provided at an upper end of the cooling device; a hydrogen gas supply device for supplying hydrogen gas into the cooling device; an inert gas supply device for supplying an inert gas into the preliminary chamber; It is equipped with:

[0011] According to the above configuration, the glass fiber passes through the preliminary chamber to which the inert gas is supplied immediately before entering the cooling device, so that the air that is pulled by the glass fiber traveling at high speed and clings to the glass fiber is replaced with the inert gas in the preliminary chamber, thereby making it possible to prevent the air from flowing into the cooling device that uses hydrogen gas for cooling.

[0012] In this specification, the expression "provided at the upper end of the cooling device" is not limited to a configuration in which the auxiliary chamber is provided only at the upper end of the cooling device, but also includes a configuration in which at least a portion of the auxiliary chamber is provided at the upper end of the cooling device.

[0013] (2) In the above (1), a plurality of the auxiliary chambers are stacked on the upper end of the cooling device, The inert gas supply device may be configured to supply the inert gas to each of the plurality of auxiliary chambers.

[0014] According to the above-mentioned configuration, by providing a plurality of preliminary chambers, the atmosphere around the glass fiber can be more reliably replaced with the inert gas.

[0015] (3) In the above (1) or (2), an oxygen concentration meter may be provided for measuring the oxygen concentration in the preliminary chamber.

[0016] According to the above configuration, by measuring the oxygen concentration in the preliminary chamber, it is possible to confirm the effect of replacing the air (oxygen) in the preliminary chamber with the inert gas.

[0017] (4) In the above (3), the hydrogen gas supply device may stop supplying hydrogen gas to the cooling device when the oxygen concentration value measured by the oxygen concentration meter exceeds a predetermined value.

[0018] According to the above configuration, even if the oxygen concentration in the spare chamber increases, the supply of hydrogen gas to the cooling device can be stopped, thereby preventing an explosion of hydrogen gas due to air flowing into the cooling device.

[0019] (5) In any one of the above (1) to (4), the preliminary chamber may be configured to cover the entire cooling device.

[0020] According to the above configuration, when the cooling device is made into a double housing, the outer housing can be used as a spare chamber. In addition, since the lower end of the cooling device is also covered by the spare chamber, the hydrogen gas drawn by the glass fiber extending from the cooling device can be replaced with an inert gas.

[0021] (6) An optical fiber manufacturing apparatus according to the present disclosure, A drawing furnace for heating and melting the optical fiber preform and drawing it. a cooling device for cooling the drawn glass fiber; a hydrogen gas supply device for supplying hydrogen gas into the cooling device; a hydrogen gas recovery device that recovers the hydrogen gas supplied into the cooling device; It is equipped with A hydrogen gas recovery port for recovering the hydrogen gas within the cooling device is provided at the bottom of the cooling device.

[0022] According to the above configuration, hydrogen gas is collected from the vicinity of the opening where the glass fiber of the cooling device exits, so that hydrogen gas pulled by the glass fiber running inside the cooling device can be prevented from leaking out of the cooling device.

[0023] (7) In the above (6), a spare chamber is provided at the upper end of the cooling device; an inert gas supply device for supplying an inert gas into the preliminary chamber; The present invention may also include:

[0024] According to the above configuration, the glass fiber passes through the preliminary chamber to which the inert gas is supplied immediately before entering the cooling device, so that the air that is pulled by the glass fiber traveling at high speed and clings to the glass fiber is replaced with the inert gas in the preliminary chamber, thereby making it possible to prevent the air from flowing into the cooling device that uses hydrogen gas for cooling.

[0025] (8) In the above item (7), the preliminary chamber may be configured to cover the entire cooling device.

[0026] According to the above configuration, when the cooling device is made into a double housing, the outer housing can be used as a spare chamber. In addition, since the lower end of the cooling device is also covered by the spare chamber, the hydrogen gas drawn by the glass fiber extending from the cooling device can be replaced with an inert gas.

[0027] (9) A method for manufacturing an optical fiber comprising the steps of: a drawing process of heating and melting an optical fiber preform and drawing the optical fiber preform; a cooling step of cooling the drawn glass fiber by passing the glass fiber through a cooling device supplied with hydrogen gas; and a replacement step of replacing the atmosphere around the glass fiber with the inert gas by passing the glass fiber through a preliminary chamber that is disposed at the upper end of the cooling device and to which an inert gas is supplied, prior to the cooling step.

[0028] According to the above method, the glass fiber passes through a preliminary chamber to which an inert gas is supplied immediately before entering the cooling device, so that the air that is pulled by the glass fiber traveling at high speed and clings to the glass fiber is replaced with the inert gas in the preliminary chamber, thereby making it possible to prevent the air from flowing into the cooling device that uses hydrogen gas for cooling.

[0029] (10) A method for manufacturing an optical fiber comprising the steps of: a drawing process of heating and melting an optical fiber preform and drawing the optical fiber preform; a cooling step of cooling the drawn glass fiber by passing the glass fiber through a cooling device supplied with hydrogen gas; and a recovery step of recovering the hydrogen gas in the lower part of the cooling device.

[0030] According to the above method, hydrogen gas is collected from the vicinity of the opening where the glass fiber of the cooling device exits, so that hydrogen gas pulled by the glass fiber running inside the cooling device can be prevented from leaking out of the cooling device.

[0031] [Details of the embodiment of the present disclosure] Specific examples of optical fiber manufacturing apparatuses and optical fiber manufacturing methods according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is intended to include all modifications within the meaning and scope of the claims as set forth in the claims. In addition, the scale of each drawing used in the following description has been appropriately changed so that each component can be recognized.

[0032] [First embodiment] (Optical fiber manufacturing equipment 1) Fig. 1 is a schematic diagram showing the configuration of an optical fiber manufacturing apparatus 1 according to a first embodiment. As illustrated in Fig. 1, the optical fiber manufacturing apparatus 1 includes a drawing furnace 2, a preliminary chamber 3, a cooling device 4, a resin applying device 5, a resin curing device 6, a winding device 7, an inert gas supplying device 8, a hydrogen gas supplying device 9, and a control device 10.

[0033] The drawing furnace 2 includes a furnace core tube 21 and a heater 22. The optical fiber preform G supplied into the furnace core tube 21 is heated and melted by the heater 22, and is drawn so as to continuously obtain a glass fiber G1 having a predetermined outer diameter.

[0034] The preliminary chamber 3 is provided at the upper end of the cooling device 4. An inert gas is supplied into the preliminary chamber 3 from an inert gas supply device 8 through a gas pipe 81. The glass fiber G1 drawn in the drawing furnace 2 passes through the preliminary chamber 3. When the glass fiber G1 passes through the preliminary chamber 3, the air that has been pulled by the glass fiber G1 and has clung to the periphery of the glass fiber G1 is replaced with the inert gas. The inert gas is, for example, argon gas or nitrogen gas.

[0035] The cooling device 4 is configured to cool the glass fiber G1. Hydrogen gas is supplied into the cooling device 4 from a hydrogen gas supply device 9 via a gas pipe 91. Although a part of the gas pipe 91a is not shown in FIG. 1, the gas pipe 91a is connected to the hydrogen gas supply device 9. The glass fiber G1 that has passed through the preliminary chamber 3 passes through the cooling device 4. The glass fiber G1 is cooled by hydrogen gas while passing through the cooling device 4. An inert gas is supplied into the cooling device 4 from an inert gas supply device 8 via a gas pipe 82. The inside of the cooling device 4 is made positively pressurized by the inert gas.

[0036] The resin applying device 5 is configured to apply resin around the glass fiber G1. The resin curing device 6 is configured to harden the resin applied around the glass fiber G1. The optical fiber G2 with the hardened resin is wound by the winding device 7.

[0037] The control device 10 controls the operation of each device. For example, the control device 10 adjusts the drawing speed of the glass fiber G1 by controlling the operation of the drawing furnace 2 and the winding device 7. For example, the control device 10 adjusts the supply amount of hydrogen gas supplied to the cooling device 4 by controlling the operation of the hydrogen gas supply device 9. The control device 10 is composed of, for example, a general-purpose computer having a general-purpose memory and a general-purpose microprocessor that operates in cooperation with the general-purpose memory.

[0038] Next, the configurations of the preliminary chamber 3 and the cooling device 4 will be described in detail with reference to FIG. 2, the preparatory chamber 3 is disposed at the upper end of the cooling device 4 in a state of contact with the upper end of the cooling device 4. A first opening 31 through which the glass fiber G1 enters is provided at the upper end of the preparatory chamber 3. A second opening 32 through which the glass fiber G1 exits is provided at the lower end of the preparatory chamber 3. The drawn glass fiber G1 enters the preparatory chamber 3 from the first opening 31, passes through the preparatory chamber 3, and exits from the second opening 32.

[0039] A gas supply port 33 for supplying an inert gas is provided on a side surface of the preliminary chamber 3. One end of a gas pipe 81 is connected to the gas supply port 33. The other end of the gas pipe 81 is connected to an inert gas supply device 8 (see FIG. 1). The inert gas supplied from the inert gas supply device 8 passes through the gas pipe 81 and is supplied from the gas supply port 33 into the preliminary chamber 3.

[0040] A first opening 41 through which the glass fiber G1 enters is provided at the upper end of the cooling device 4. The first opening 41 is formed so as to communicate with the second opening 32 of the preliminary chamber 3. A second opening 42 through which the glass fiber G1 exits is provided at the lower end of the cooling device 4. The glass fiber G1 that has passed through the preliminary chamber 3 enters the cooling device 4 from the first opening 41, passes through the cooling device 4, and exits from the second opening 42.

[0041] A gas supply port 43 for supplying an inert gas is provided on the side of the cooling device 4. In this example, the gas supply port 43 is provided below the center in the longitudinal direction (the vertical direction in the figure). One end of a gas pipe 82 is connected to the gas supply port 43. The other end of the gas pipe 82 is connected to an inert gas supply device 8 (see FIG. 1). The inert gas supplied from the inert gas supply device 8 is supplied through the gas pipe 82 to the preliminary chamber 3 from the gas supply port 43.

[0042] A gas supply port 44 for supplying hydrogen gas is provided on the side of the upper part of the cooling device 4. One end of a gas pipe 91 is connected to the gas supply port 44. The other end of the gas pipe 91 is connected to a hydrogen gas supply device 9 (see FIG. 1). Hydrogen gas supplied from the hydrogen gas supply device 9 passes through the gas pipe 91 and is supplied from the gas supply port 44 into the cooling device 4. In this example, the gas supply port 44a and the gas supply port 44b are provided at positions facing each other, and hydrogen gas supplied from the hydrogen gas supply device 9 passes through the gas pipes 91a and 91b and is supplied from the gas supply ports 44a and 44b into the cooling device 4. In this example, the gas pipes 91a and 91b extend inward from the gas supply ports 44a and 44b, and supply hydrogen gas to a position closer to the glass fiber G1.

[0043] The cooling device 4 has therein a cooling passage 45. A cooling medium flows within the cooling passage 45.

[0044] [Optical fiber manufacturing method] Next, a method for manufacturing an optical fiber using the optical fiber manufacturing apparatus 1 will be described.

[0045] First, the optical fiber preform G is heated, melted, and drawn in the drawing furnace 2 (drawing process). Specifically, the optical fiber preform G is suspended in the furnace tube 21 by a preform suspension mechanism (not shown), and the lower part of the optical fiber preform G is heated and melted by the heater 22. The molten optical fiber preform G becomes a glass fiber G1 having a predetermined outer diameter by the weight and tensile force of the molten glass, and is continuously drawn.

[0046] The drawn glass fiber G1 passes continuously through a preliminary chamber 3 before passing through a cooling device 4. An inert gas is supplied into the preliminary chamber 3 from an inert gas supplying device 8, and the atmosphere around the glass fiber G1 passing through the preliminary chamber 3 is replaced with the inert gas (replacement step). For example, the inert gas creates a positive pressure in the preliminary chamber 3, and the atmosphere pulled by the glass fiber G1 is prevented from flowing into the preliminary chamber 3.

[0047] The glass fiber G1 that has passed through the preliminary chamber 3 passes continuously through the cooling device 4. Since the cooling device 4 is provided at the lower end of the preliminary chamber 3, the glass fiber G1 that has passed through the preliminary chamber 3 enters the cooling device 4 without being exposed to the atmosphere. Hydrogen gas is supplied into the cooling device 4 from a hydrogen gas supply device 9, and the glass fiber G1 passing through the cooling device 4 is cooled by the hydrogen gas (cooling step). In this example, the hydrogen gas is cooled by a cooling solvent flowing through a cooling passage 45, and the glass fiber G1 passing through the cooling device 4 is cooled by the cooled hydrogen gas.

[0048] In addition, an inert gas is supplied into the cooling device 4 from an inert gas supply device 8, and the inert gas creates positive pressure inside the cooling device 4, thereby preventing the air pulled by the glass fiber G1 from flowing into the cooling device 4.

[0049] A resin is applied around the glass fiber G1 that has passed through the cooling device 4 by a resin application device 5. The resin applied around the glass fiber G1 is then hardened by a resin hardening device 6 to form the optical fiber G2. The optical fiber G2 is wound up by a winding device 7.

[0050] Here, hydrogen gas used as the refrigerant gas in the cooling device 4 is easier to obtain than helium gas, and has a higher thermal conductivity than helium gas, so that the glass fiber G1 can be cooled efficiently. As a result, even when the drawing speed of the glass fiber G1 is high, the glass fiber G1 can be sufficiently cooled, improving the productivity of the optical fiber G2. On the other hand, hydrogen gas is a flammable gas, and will explode if mixed with air (oxygen) at a concentration above a certain value.

[0051] According to the optical fiber manufacturing apparatus 1 and the optical fiber manufacturing method of the first embodiment, the glass fiber G1 passes through the preliminary chamber 3 to which an inert gas is supplied immediately before entering the cooling device 4, so that the air that has been pulled by the glass fiber G1 traveling at high speed and clung to the periphery of the glass fiber G1 is replaced with the inert gas in the preliminary chamber 3. This makes it possible to prevent air from flowing into the cooling device 4 to which hydrogen gas is supplied.

[0052] In addition, in this embodiment, since an inert gas is supplied into the cooling device 4, the inside of the cooling device 4 is made positively pressurized, and it is possible to further prevent the air pulled by the glass fiber G1 from flowing into the cooling device 4. The hydrogen gas is diluted with the inert gas in the cooling device 4 and is discharged from the second opening 42. The flow rates of the inert gas and hydrogen gas supplied into the cooling device 4 are set so that an explosion will not occur even if the hydrogen gas mixes with the air.

[0053] In this embodiment, the inside of the preliminary chamber 3 is made positively pressurized by the inert gas to prevent the air pulled by the glass fiber G1 from flowing into the preliminary chamber 3. However, for example, a gas exhaust port (not shown) may be provided in the preliminary chamber 3 so that the air pulled by the glass fiber G1 and flowing into the preliminary chamber 3 is pushed out by the inert gas and discharged from the gas exhaust port.

[0054] (Variation 1) In the above-described first embodiment, one pre-chamber 3 is disposed at the upper end of the cooling device 4. However, a plurality of pre-chambers 3 may be stacked and disposed at the upper end of the cooling device 4.

[0055] Fig. 3 shows a configuration example of an optical fiber manufacturing apparatus 1A according to Modification 1. The optical fiber manufacturing apparatus 1A according to Modification 1 differs from the optical fiber manufacturing apparatus 1 shown in Fig. 2 in the configuration of the preliminary chamber 3. For convenience of explanation, explanations of members having the same reference numbers as members already explained in the explanation of the first embodiment above will be omitted.

[0056] 3, in the optical fiber manufacturing apparatus 1A according to the first modification, two preliminary chambers 3a, 3b are arranged in a stacked manner at the upper end of the cooling device 4. Specifically, the preliminary chamber 3b is arranged at the upper end of the cooling device 4, and the preliminary chamber 3a is arranged at the upper end of the preliminary chamber 3b.

[0057] A first opening 31a through which the glass fiber G1 enters is provided at the top end of the preliminary chamber 3a. A second opening 32a through which the glass fiber G1 exits is provided at the bottom end of the preliminary chamber 3a. A gas supply port 33a for supplying an inert gas is provided at a side of the preliminary chamber 3a. One end of a gas pipe 81a is connected to the gas supply port 33a. The other end of the gas pipe 81a is connected to an inert gas supply device 8 (see FIG. 1). The inert gas supplied from the inert gas supply device 8 is supplied into the preliminary chamber 3 from the gas supply port 33a through the gas pipe 81a.

[0058] A first opening 31b for the glass fiber G1 to enter is provided at the upper end of the preliminary chamber 3b. The first opening 31b is formed so as to communicate with the second opening 32a of the preliminary chamber 3a. A second opening 32b for the glass fiber G1 to exit is provided at the lower end of the preliminary chamber 3b. The second opening 32b is formed so as to communicate with the first opening 41 of the cooling device 4. A gas supply port 33b for supplying an inert gas is provided at the side of the preliminary chamber 3b. One end of a gas pipe 81b is connected to the gas supply port 33b. The other end of the gas pipe 81b is connected to the inert gas supply device 8 (see FIG. 1). The inert gas supplied from the inert gas supply device 8 is supplied into the preliminary chamber 3 from the gas supply port 33b through the gas pipe 81b.

[0059] The glass fiber G1 drawn by the drawing furnace 2 passes successively through the preliminary chambers 3a and 3b before passing through the cooling device 4. An inert gas is supplied into the preliminary chamber 3a from an inert gas supply device 8, and the atmosphere around the glass fiber G1 passing through the preliminary chamber 3a is replaced with the inert gas.

[0060] In addition, an inert gas is supplied from an inert gas supply device 8 into the preliminary chamber 3b, and the atmosphere around the glass fiber G1 passing through the preliminary chamber 3b is replaced with the inert gas.

[0061] According to the optical fiber manufacturing apparatus 1A of the first variant, the glass fiber G1 passes through two preliminary chambers 3a, 3b to which an inert gas is supplied just before entering the cooling device 4, so that the atmosphere around the glass fiber G1 can be more reliably replaced with an inert gas.

[0062] In this modified example, each of the preliminary chambers 3a and 3b may be provided with a gas exhaust port (not shown), and the air that has been pulled by the glass fiber G1 and flowed into the preliminary chambers 3a and 3b may be pushed out by an inert gas and discharged from the gas exhaust port.

[0063] In this modification, three or more pre-chambers 3 may be stacked on top of each other on the upper end of the cooling device 4.

[0064] (Variation 2) In the above-described first embodiment, the preliminary chamber 3 is provided only at the upper end of the cooling device 4. However, the preliminary chamber 3 may be provided so as to cover the entire cooling device 4 including the side and lower end of the cooling device 4 in addition to the upper end of the cooling device 4.

[0065] Fig. 4 shows an example of the configuration of an optical fiber manufacturing apparatus 1B according to Modification 2. The optical fiber manufacturing apparatus 1B according to Modification 2 differs from the optical fiber manufacturing apparatus 1 shown in Fig. 2 in the configuration of the preliminary chamber 3. For convenience of explanation, explanations of members having the same reference numbers as those already explained in the explanation of the first embodiment above will be omitted.

[0066] As illustrated in FIG. 4, an optical fiber manufacturing apparatus 1B according to the second modification includes a preliminary chamber 3A configured to cover the entire cooling device 4. As shown in FIG.

[0067] A first opening 31A for the glass fiber G1 to enter is provided at the top end of the preliminary chamber 3A. A second opening 32A for the glass fiber G1 to exit is provided at the bottom end of the preliminary chamber 3A. A gas supply port 33A for supplying an inert gas is provided at a side of the preliminary chamber 3A. One end of a gas pipe 81 is connected to the gas supply port 33A. The other end of the gas pipe 81 is connected to an inert gas supply device 8 (see FIG. 1). The inert gas supplied from the inert gas supply device 8 is supplied into the preliminary chamber 3 from the gas supply port 33A through the gas pipe 81.

[0068] The glass fiber G1 drawn by the drawing furnace 2 enters the preliminary chamber 3A before passing through the cooling device 4. An inert gas is supplied into the preliminary chamber 3A from an inert gas supplying device 8, and the atmosphere around the glass fiber G1 passing through the preliminary chamber 3A is replaced with the inert gas. For example, the inert gas creates a positive pressure inside the preliminary chamber 3A, thereby preventing the atmosphere pulled by the glass fiber G1 from flowing into the preliminary chamber 3A.

[0069] The glass fiber G1 that has passed through the upper part of the preliminary chamber 3A passes continuously through the cooling device 4. Since the preliminary chamber 3 is provided so as to cover the entire cooling device 4, the glass fiber G1 passes through the cooling device 4 without being exposed to the atmosphere. Hydrogen gas is supplied into the cooling device 4 from a hydrogen gas supply device 9, and the glass fiber G1 passing through the cooling device 4 is cooled by the hydrogen gas.

[0070] The glass fiber G1 that has passed through the cooling device 4 passes through the preliminary chamber 3A again. Since the inert gas is supplied from the inert gas supply device 8 into the preliminary chamber 3A, the hydrogen gas pulled by the glass fiber G1 exiting from the second opening 42 of the cooling device 4 is replaced with the inert gas. For example, the inert gas creates a positive pressure inside the preliminary chamber 3A, thereby preventing the hydrogen gas pulled by the glass fiber G1 from flowing out of the cooling device 4. The hydrogen gas is diluted with the inert gas in the cooling device 4, and is further diluted with the inert gas in the preliminary chamber 3A before being discharged from the first opening 31A or the second opening 32A. Since the hydrogen gas is sufficiently diluted with the inert gas before being discharged from the preliminary chamber 3A, it does not mix with the atmosphere and explode.

[0071] According to the optical fiber manufacturing apparatus 1B of the second modification, when the cooling device 4 is provided in a double housing, the outer housing can be used as the spare chamber 3A. In addition, since the lower end of the cooling device 4 is also covered by the spare chamber 3A, the hydrogen gas drawn by the glass fiber G1 exiting from the cooling device 4 can be replaced with an inert gas.

[0072] (Variation 3) Fig. 5 shows a configuration example of an optical fiber manufacturing apparatus 1C according to Modification 3. The optical fiber manufacturing apparatus 1C according to Modification 3 has a configuration in which an oxygen concentration meter 11 is added to the optical fiber manufacturing apparatus 1 shown in Fig. 2. For convenience of explanation, explanations of members having the same reference numbers as members already explained in the explanation of the first embodiment above will be omitted.

[0073] 5, in the optical fiber manufacturing apparatus 1C according to the third modification, an oxygen concentration meter 11 is disposed in the preliminary chamber 3. The oxygen concentration meter 11 is configured to measure the oxygen concentration in the preliminary chamber 3. The hydrogen gas supply device 9 is configured to stop the supply of hydrogen gas to the cooling device 4 when the oxygen concentration measured by the oxygen concentration meter 11 exceeds a predetermined value.

[0074] Specifically, oxygen concentration meter 11 outputs information on the measured oxygen concentration value to control device 10. When control device 10 determines that the oxygen concentration value in preliminary chamber 3 obtained by oxygen concentration meter 11 has exceeded a predetermined value, it outputs a control signal to hydrogen gas supply device 9 to stop the supply of hydrogen gas to cooling device 4. Hydrogen gas supply device 9 stops the supply of hydrogen gas to cooling device 4 based on the control signal.

[0075] According to the optical fiber manufacturing apparatus 1C of the third modification, the oxygen concentration in the preliminary chamber 3 is measured, whereby the effect of replacing the air (oxygen) in the preliminary chamber 3 with the inert gas can be confirmed.

[0076] Furthermore, even if the oxygen concentration in the preliminary chamber 3 increases, the supply of hydrogen gas into the cooling device 4 can be stopped, thereby preventing an explosion of hydrogen gas due to the inflow of air into the cooling device 4.

[0077] [Second embodiment] Next, an optical fiber manufacturing apparatus 1D according to a second embodiment will be described with reference to Fig. 6. For convenience of explanation, explanations of members having the same reference numbers as those already explained in the first embodiment will be omitted.

[0078] Fig. 6 shows an example of the configuration of an optical fiber manufacturing apparatus 1D according to the second embodiment. Fig. 7 shows the configuration of a cooling device 4A of the optical fiber manufacturing apparatus 1D.

[0079] As illustrated in FIG. 6, the optical fiber manufacturing apparatus 1D includes a drawing furnace 2, a cooling device 4A, a resin application device 5, a resin hardening device 6, a winding device 7, an inert gas supply device 8, a hydrogen gas supply device 9, a control device 10, and a hydrogen gas recovery device 12.

[0080] The glass fiber G1 drawn in the drawing furnace 2 passes through a cooling device 4A. Hydrogen gas is supplied into the cooling device 4A from a hydrogen gas supply device 9 through a gas pipe 91. The glass fiber G1 is cooled by the hydrogen gas while passing through the cooling device 4A. In addition, an inert gas is supplied into the cooling device 4A from an inert gas supply device 8 through a gas pipe 82. The inside of the cooling device 4A is made positively pressurized by the inert gas.

[0081] As illustrated in FIG. 7, a gas recovery port 46 for recovering hydrogen gas is provided on the side surface of the lower part of the cooling device 4A. One end of a gas pipe 121 is connected to the gas recovery port 46. The other end of the gas pipe 121 is connected to the hydrogen gas recovery device 12 (see FIG. 6). A mixed gas containing hydrogen gas and an inert gas supplied into the cooling device 4A is sucked from the gas recovery port 46 and recovered in the hydrogen gas recovery device 12. In this example, the gas recovery port 46a and the gas recovery port 46b are provided at positions facing each other, and the mixed gas sucked from the gas recovery port 46a and the gas recovery port 46b is recovered in the hydrogen gas recovery device 12 through the gas pipes 121a and 121b. Note that, although a part of the gas pipe 121b is not shown in FIG. 6, the gas pipe 121b is connected to the hydrogen gas recovery device 12. In this example, the gas pipes 121a and 121b extend more inward than the gas recovery ports 46a and 46b, and recover the hydrogen gas at a position closer to the glass fiber G1.

[0082] In the optical fiber manufacturing method using such an optical fiber manufacturing apparatus 1D, first, the optical fiber preform G is heated and melted in the drawing furnace 2 and drawn (drawing step).

[0083] The glass fiber G1 drawn in the drawing furnace 2 passes continuously through the cooling device 4A. Hydrogen gas is supplied into the cooling device 4A from a hydrogen gas supply device 9, and the glass fiber G1 passing through the cooling device 4A is cooled by the hydrogen gas (cooling step). In this example, the hydrogen gas is cooled by a cooling solvent flowing through a cooling passage 45, and the glass fiber G1 passing through the cooling device 4A is cooled by the cooled hydrogen gas.

[0084] In addition, an inert gas is supplied into the cooling device 4A from an inert gas supply device 8, and the inert gas creates positive pressure inside the cooling device 4A, thereby preventing the air pulled by the glass fiber G1 from flowing into the cooling device 4A.

[0085] At the bottom of the cooling device 4A, a mixed gas containing hydrogen gas and an inert gas inside the cooling device 4A is sucked in through the gas recovery port 46, and the sucked mixed gas passes through the gas piping 121 and is recovered in the hydrogen gas recovery device 12 (recovery process).

[0086] According to the optical fiber manufacturing apparatus 1D and the optical fiber manufacturing method of the second embodiment, hydrogen gas is recovered just before the second opening 42 of the cooling device 4A, so that the hydrogen gas carried by the glass fiber G1 traveling within the cooling device 4A can be prevented from leaking out of the cooling device 4A.

[0087] The hydrogen gas recovery device 12 may be configured to separate and purify hydrogen gas from the mixed gas sucked through the gas recovery port 46, and regenerate the hydrogen gas into a reusable state. The hydrogen gas recovery device 12 and the hydrogen gas supply device 9 may be connected by piping (not shown), and the hydrogen gas regenerated by the hydrogen gas recovery device 12 may be supplied to the hydrogen gas supply device 9.

[0088] (Variation 4) In the above-described second embodiment, the optical fiber manufacturing apparatus 1D may have one or more pre-chambers 3 disposed at the upper end of the cooling device 4A, like the optical fiber manufacturing apparatus 1 according to the first embodiment.

[0089] Fig. 8 shows a configuration example of an optical fiber manufacturing apparatus 1E according to Modification 4. The optical fiber manufacturing apparatus 1E according to Modification 4 has a configuration in which a preliminary chamber 3 is added to the optical fiber manufacturing apparatus 1D shown in Fig. 7. For convenience of explanation, explanations of members having the same reference numbers as the members already explained in the explanations of the first and second embodiments above will be omitted.

[0090] As illustrated in Fig. 8, the optical fiber manufacturing apparatus 1E includes a pre-chamber 3 provided at the upper end of the cooling device 4A. The pre-chamber 3 is disposed at the upper end of the cooling device 4A in a state of contact with the upper end of the cooling device 4A. The upper end of the pre-chamber 3 is provided with a first opening 31 through which the glass fiber G1 enters. The lower end of the pre-chamber 3 is provided with a second opening 32 through which the glass fiber G1 exits. The drawn glass fiber G1 enters the pre-chamber 3 from the first opening 31, passes through the pre-chamber 3, and exits from the second opening 32.

[0091] A gas supply port 33 for supplying an inert gas is provided on a side surface of the preliminary chamber 3. The inert gas is, for example, argon gas or nitrogen gas. One end of a gas pipe 81 is connected to the gas supply port 33. The other end of the gas pipe 81 is connected to an inert gas supply device 8 (see FIG. 6). The inert gas supplied from the inert gas supply device 8 is supplied into the preliminary chamber 3 from the gas supply port 33 through the gas pipe 81.

[0092] The glass fiber G1 drawn in the drawing furnace 2 passes continuously through the preliminary chamber 3 before passing through the cooling device 4A. An inert gas is supplied into the preliminary chamber 3 from an inert gas supply device 8, and the atmosphere around the glass fiber G1 passing through the preliminary chamber 3 is replaced with the inert gas (replacement step). For example, the inert gas creates a positive pressure in the preliminary chamber 3 of the cooling device 4A, and the atmosphere pulled by the glass fiber G1 is prevented from flowing into the preliminary chamber 3.

[0093] The glass fiber G1 that has passed through the preliminary chamber 3 passes continuously through the cooling device 4A. Since the cooling device 4A is provided at the lower end of the preliminary chamber 3, the glass fiber G1 that has passed through the preliminary chamber 3 enters the cooling device 4A without being exposed to the atmosphere. Hydrogen gas is supplied into the cooling device 4A from a hydrogen gas supply device 9, and the glass fiber G1 passing through the cooling device 4A is cooled by the hydrogen gas (cooling step). In this example, the hydrogen gas is cooled by a cooling solvent flowing through a cooling passage 45, and the glass fiber G1 passing through the cooling device 4A is cooled by the cooled hydrogen gas.

[0094] According to the optical fiber manufacturing apparatus 1E and the optical fiber manufacturing method of the fourth modification, the glass fiber G1 passes through the preliminary chamber 3 to which an inert gas is supplied immediately before entering the cooling device 4A, so that the air that has been pulled by the glass fiber G1 traveling at high speed and clung to the periphery of the glass fiber G1 is replaced with the inert gas in the preliminary chamber 3. This makes it possible to prevent the air from flowing into the cooling device 4A that uses hydrogen gas for cooling.

[0095] (Variation 5) In the above-mentioned variant example 4, the preliminary chamber 3 is provided only at the upper end of the cooling device 4A, but the preliminary chamber 3 may be provided so as to cover the entire cooling device 4A, including the upper end as well as the sides and lower end of the cooling device 4A.

[0096] Fig. 9 shows a configuration example of an optical fiber manufacturing apparatus 1F according to Modification 5. The optical fiber manufacturing apparatus 1F according to Modification 5 differs from the optical fiber manufacturing apparatus 1E shown in Fig. 8 in the configuration of the preliminary chamber 3. For convenience of explanation, explanations of members having the same reference numbers as those already explained in the explanations of Modifications 2 and 4 above will be omitted.

[0097] As illustrated in FIG. 9, an optical fiber manufacturing apparatus 1F according to the fifth modification includes a preliminary chamber 3A configured to entirely cover a cooling device 4A.

[0098] A first opening 31A for the glass fiber G1 to enter is provided at the top end of the preliminary chamber 3A. A second opening 32A for the glass fiber G1 to exit is provided at the bottom end of the preliminary chamber 3A. A gas supply port 33A for supplying an inert gas is provided at the side of the preliminary chamber 3A. One end of a gas pipe 81 is connected to the gas supply port 33A. The other end of the gas pipe 81 is connected to an inert gas supply device 8 (see FIG. 6). The inert gas supplied from the inert gas supply device 8 is supplied from the gas supply port 33A through the gas pipe 81 into the preliminary chamber 3A.

[0099] The glass fiber G1 drawn by the drawing furnace 2 enters the preliminary chamber 3A before passing through the cooling device 4A. An inert gas is supplied into the preliminary chamber 3A from an inert gas supply device 8, and the atmosphere around the glass fiber G1 passing through the upper part of the preliminary chamber 3A is replaced with the inert gas. For example, the inert gas creates a positive pressure inside the preliminary chamber 3, thereby preventing the atmosphere pulled by the glass fiber G1 from flowing into the preliminary chamber 3.

[0100] The glass fiber G1 that has passed through the upper part of the preliminary chamber 3A passes continuously through the cooling device 4A. Since the preliminary chamber 3A is provided so as to cover the entire cooling device 4A, the glass fiber G1 passes through the cooling device 4A without being exposed to the atmosphere. Hydrogen gas is supplied into the cooling device 4A from a hydrogen gas supply device 9, and the glass fiber G1 passing through the cooling device 4A is cooled by the hydrogen gas.

[0101] The glass fiber G1 that has passed through the cooling device 4A passes through the preliminary chamber 3A again. Since an inert gas is supplied into the preliminary chamber 3A from an inert gas supplying device 8, the hydrogen gas pulled by the glass fiber G1 exiting from the second opening 42 of the cooling device 4A is replaced with the inert gas. For example, the inside of the preliminary chamber 3 is made positively pressurized by the inert gas, so that the hydrogen gas pulled by the glass fiber G1 is prevented from flowing out of the cooling device 4A.

[0102] According to the optical fiber manufacturing apparatus 1F of the fifth modification, when the cooling device 4A is configured as a double housing, the outer housing can be used as the spare chamber 3A. In addition, since the lower end of the cooling device 4A is also covered by the spare chamber 3A, the hydrogen gas drawn by the glass fiber G1 exiting from the second opening 42 of the cooling device 4A can be replaced with an inert gas.

[0103] Although the present disclosure has been described in detail and with reference to specific embodiments, it is clear to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present disclosure. 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 disclosure. [Explanation of symbols]

[0104] 1: Optical fiber manufacturing equipment 1A: Optical fiber manufacturing equipment 1B: Optical fiber manufacturing equipment 1C: Optical fiber manufacturing equipment 1D: Optical fiber manufacturing equipment 1E: Optical fiber manufacturing equipment 1F: Optical fiber manufacturing equipment 2: Wire drawing furnace 3: Spare room 3a: Spare room 3A: Spare room 3b: Preparatory room 4: Cooling device 4A: Cooling device 5: Resin application device 6:Resin curing equipment 7: Winding device 8: Inert gas supply device 9: Hydrogen gas supply device 10: Control device 11: Oxygen concentration meter 12: Hydrogen gas recovery device 21: Furnace tube 22: Heater 31:First opening 31a: First opening 31A: First opening 31b: First opening 32:Second opening 32a:Second opening 32A:Second opening 32b:Second opening 33: Gas supply port 33a: Gas supply port 33A: Gas supply port 33b: Gas supply port 41:First opening 42:Second opening 43: Gas supply port 44: Gas supply port 44a: Gas supply port 44b: Gas supply port 45: Cooling passage 46: Gas recovery port 46a: Gas recovery port 46b: Gas recovery port 81: Gas piping 81a: Gas piping 81b: Gas piping 82: Gas piping 91: Gas piping 91a: Gas piping 91b: Gas piping 121: Gas piping 121a: Gas piping 121b: Gas piping G: Optical fiber base material G1: Glass fiber G2: Optical fiber

Claims

1. a drawing furnace for heating and melting the optical fiber preform and drawing it; a cooling device for cooling the drawn glass fiber; A spare chamber provided at an upper end of the cooling device; a hydrogen gas supply device for supplying hydrogen gas into the cooling device; an inert gas supply device for supplying an inert gas into the preliminary chamber; An optical fiber manufacturing apparatus comprising:

2. A plurality of the auxiliary chambers are stacked on an upper end of the cooling device, 2. The optical fiber manufacturing apparatus according to claim 1, wherein the inert gas supply device is configured to supply the inert gas to each of the plurality of auxiliary chambers.

3. 3. The optical fiber manufacturing apparatus according to claim 1, further comprising an oxygen concentration meter for measuring an oxygen concentration in the preliminary chamber.

4. 4. The optical fiber manufacturing apparatus according to claim 3, wherein the hydrogen gas supply device stops supplying hydrogen gas to the cooling device when the oxygen concentration value measured by the oxygen concentration meter exceeds a predetermined value.

5. 3. The optical fiber manufacturing apparatus according to claim 1, wherein the auxiliary chamber is configured to cover the entire cooling device.

6. A drawing furnace for heating and melting the optical fiber preform and drawing it. a cooling device for cooling the drawn glass fiber; a hydrogen gas supply device for supplying hydrogen gas into the cooling device; a hydrogen gas recovery device that recovers the hydrogen gas supplied into the cooling device; Equipped with an optical fiber manufacturing apparatus, wherein a hydrogen gas recovery port for recovering the hydrogen gas within the cooling device is provided at a lower portion of the cooling device;

7. A spare chamber provided at an upper end of the cooling device; an inert gas supply device for supplying an inert gas into the preliminary chamber; 7. The optical fiber manufacturing apparatus according to claim 6, comprising:

8. The optical fiber manufacturing apparatus according to claim 7 , wherein the preliminary chamber is configured to cover the entire cooling device.

9. a drawing process of heating and melting an optical fiber preform and drawing the optical fiber preform; a cooling step of cooling the drawn glass fiber by passing the glass fiber through a cooling device supplied with hydrogen gas; and a replacement step of, prior to the cooling step, passing the glass fiber through a preliminary chamber that is disposed at an upper end of the cooling device and to which an inert gas is supplied, thereby replacing the atmosphere around the glass fiber with the inert gas.

10. a drawing process of heating and melting an optical fiber preform and drawing the optical fiber preform; a cooling step of cooling the drawn glass fiber by passing the glass fiber through a cooling device supplied with hydrogen gas; and a recovery step of recovering the hydrogen gas inside the cooling device at a lower portion of the cooling device.

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