Apparatus and method for manufacturing optical fiber preform

Abstract

To provide an apparatus and method for manufacturing an optical fiber preform, capable of efficiently collecting germanium from exhaust gas when manufacturing the optical fiber preform.SOLUTION: An apparatus for manufacturing an optical fiber preform obtained by blowing and depositing glass fine particles on a target rotating in a reaction vessel includes a glass fine particle collection part for collecting glass fine particles from exhaust gas including the glass fine particles exhausted from a first exhaust port. The reaction vessel includes the first exhaust port and a second exhaust port for exhausting the exhaust gas including non-deposited glass fine particles; the first exhaust port is arranged in the direction in which a first burner ejects a first glass raw material; and the second exhaust port is arranged at a position distant from the first burner rather than the first exhaust port.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Germanium (Ge) is used as a raw material for various industrial products, such as semiconductor materials for diodes and the like, and as an additive for the core of glass optical fibers. The price of Ge has been rising sharply in recent years. For example, Patent Document 1 discloses a technique for recovering Ge. Patent Document 1 discloses a technique for recovering fine particles containing Ge using a bag filter, purifying the recovered fine particles with hydrochloric acid gas, and reusing them in the optical fiber manufacturing process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-2088 A Summary of the Invention [Problem to be solved by the invention]

[0004] During the manufacture of optical fibers, some of the germanium, which is an additive to the core of the optical fiber, is not used in the production of the core and is discharged as exhaust gas. The amount of germanium contained in the exhaust gas is very small, so it has not been easy to efficiently recover the germanium.

[0005] An object of the present disclosure is to provide an apparatus and method for manufacturing an optical fiber preform that can efficiently recover germanium from exhaust gases during the manufacture of an optical fiber preform. [Means for solving the problem]

[0006] The manufacturing apparatus for an optical fiber preform according to the present disclosure comprises: a first burner for spraying a first glass raw material containing a germanium compound to synthesize germanium-containing glass particles; a second burner for injecting a second glass raw material not containing a germanium compound to synthesize germanium-free glass particles; a reaction vessel having the first burner and the second burner disposed therein; An apparatus for manufacturing an optical fiber preform, comprising: the reaction vessel has a first exhaust port and a second exhaust port for discharging exhaust gas containing undeposited glass particles; the first exhaust port is arranged in a direction in which the first burner sprays the first glass frit, the second exhaust port is disposed at a position farther from the first burner than the first exhaust port, an exhaust gas treatment unit for treating the exhaust gas containing glass particles discharged from the second exhaust port; and a glass particle recovery section that recovers glass particles from the exhaust gas containing glass particles discharged from the first exhaust port.

[0007] The method for producing an optical fiber preform according to the present disclosure uses the above-mentioned optical fiber preform manufacturing apparatus to deposit glass particles on a target rotating within the reaction vessel to produce an optical fiber preform. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an apparatus and method for manufacturing an optical fiber preform that can efficiently recover germanium from exhaust gas during the manufacture of an optical fiber preform. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the state of production of an optical fiber preform inside a reaction vessel according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing the configuration of an apparatus for manufacturing an optical fiber preform according to the first embodiment of the present disclosure. [Diagram 3]FIG. 3 is a diagram showing the configuration of an apparatus for manufacturing an optical fiber preform according to the second embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram showing the configuration of an apparatus for manufacturing an optical fiber preform according to the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. The manufacturing apparatus for an optical fiber preform according to the embodiment includes: (1) a first burner for spraying a first glass raw material containing a germanium compound to synthesize germanium-containing glass particles; a second burner for injecting a second glass raw material not containing a germanium compound to synthesize germanium-free glass particles; a reaction vessel having the first burner and the second burner disposed therein; An apparatus for manufacturing an optical fiber preform, comprising: the reaction vessel has a first exhaust port and a second exhaust port for discharging exhaust gas containing undeposited glass particles; the first exhaust port is arranged in a direction in which the first burner sprays the first glass frit, the second exhaust port is disposed at a position farther from the first burner than the first exhaust port, an exhaust gas treatment unit for treating the exhaust gas containing glass particles discharged from the second exhaust port; and a glass particle recovery section that recovers glass particles from the exhaust gas containing glass particles discharged from the first exhaust port.

[0011] According to the manufacturing apparatus having the above-described configuration, exhaust gas containing a large amount of glass particles containing a high concentration of germanium can be selectively recovered by the first exhaust port, and then the glass particles can be recovered in the glass particle recovery section, thereby enabling efficient recovery of germanium.

[0012] (2) The manufacturing apparatus for the optical fiber preform described above in (1) is The first exhaust port and the second exhaust port may be inlets of a first exhaust pipe and a second exhaust pipe, respectively, that are formed by providing a partition inside one exhaust pipe.

[0013] According to the manufacturing apparatus having the above-described configuration, instead of providing separate exhaust pipes connected to the reaction vessel, one exhaust pipe is partitioned and arranged as a first exhaust pipe and a second exhaust pipe, whereby glass microparticles containing germanium at high concentrations can be selectively recovered, thereby reducing the cost of recovering germanium.

[0014] (3) The manufacturing apparatus for the optical fiber preform according to (1) or (2) above, The glass particle recovery section may include a ceramic filter or a bag filter.

[0015] The use of a ceramic filter allows the device to be made more compact. In addition, when the exhaust gas contains fluorine, the use of a bag filter allows the glass particles to be collected more effectively. It is preferable to use a bag filter that has excellent heat resistance.

[0016] (4) Any one of the above-mentioned (1) to (3) manufacturing apparatus for optical fiber preforms, The glass particle recovery section may be configured to recover glass particles deposited on a filter by backwashing.

[0017] Backwashing makes it possible to recover glass particles while suppressing an increase in pressure loss in the filter due to clogging.

[0018] (5) Any one of the above (1) to (4) manufacturing apparatus for optical fiber preforms, The apparatus may further include a collector for collecting liquid contained in the exhaust gas discharged from the glass particle recovery section.

[0019] The collection section can collect liquids such as hydrochloric acid in which germanium may be dissolved, thereby improving the amount of germanium recovered.

[0020] (6) Any one of the optical fiber preform manufacturing apparatuses (1) to (5) above, The glass particle recovery section may include a water-repellent filter.

[0021] The water-repellent filter can prevent an aqueous solution such as hydrochloric acid, which dissolves glass particles, from passing through, thereby improving the efficiency of recovering germanium.

[0022] (7) Any one of the optical fiber preform manufacturing apparatuses (1) to (6) above, The glass soot recovery section may be configured to be capable of adjusting the temperature so as not to lower the temperature of the exhaust gas discharged from the first exhaust port.

[0023] By configuring the filter to be temperature adjustable so as not to lower the temperature of the exhaust gas, it is possible to prevent hydrochloric acid from being generated by moisture contained in the exhaust gas, and to prevent germanium contained in the glass microparticles from passing through the filter.

[0024] (8) Any one of the above-mentioned (1) to (7) manufacturing apparatus for optical fiber preforms, The glass particle recovery section may be configured to recover glass particles deposited on a filter by backwashing, and to be able to perform the deposition of the glass particles on the filter and the recovery of the glass particles deposited on the filter by backwashing in parallel.

[0025] By being able to carry out the deposition of glass particles on the filter and the recovery of the glass particles deposited on the filter by backwashing in parallel, the recovery of the glass particles can be carried out continuously, thereby improving the efficiency of recovery of germanium.

[0026] (9) An apparatus for manufacturing an optical fiber preform according to any one of (1) to (8) above, The exhaust gas treatment device may further include a non-recovery circuit for sending exhaust gas from an exhaust pipe connecting the first exhaust port and the glass particle recovery section to the exhaust gas treatment section without passing through the glass particle recovery section.

[0027] By providing the non-recovery circuit, even if an abnormality occurs in the glass particle recovery section, the production of the optical fiber preform in the reaction vessel can be continued.

[0028] The method for producing an optical fiber preform according to the embodiment includes the steps of: (10) Using any one of the optical fiber preform manufacturing apparatuses (1) to (9) above, glass particles are deposited on a target rotating in the reaction vessel to manufacture an optical fiber preform.

[0029] According to the manufacturing method having the above-described configuration, exhaust gas containing a large amount of glass particles containing a high concentration of germanium is selectively recovered by the first exhaust port, and then the glass particles are recovered in the glass particle recovery section, thereby making it possible to manufacture an optical fiber preform while efficiently recovering germanium.

[0030] [Details of the embodiment of the present disclosure] First embodiment Hereinafter, the details of a first embodiment of the optical fiber preform manufacturing apparatus and method of manufacturing an optical fiber preform according to the present disclosure will be described with reference to the drawings. Fig. 1 is a diagram showing the manufacturing process of an optical fiber preform 10 inside a reaction vessel 20 according to the first embodiment. Fig. 2 is a diagram showing the configuration of an optical fiber preform manufacturing apparatus 1 according to the first embodiment. As shown in Fig. 2, the manufacturing apparatus 1 includes a reaction vessel 20, an exhaust gas treatment unit 50, and a glass microparticle recovery unit 60.

[0031] The reaction vessel 20 is configured to manufacture the optical fiber preform 10 by spraying and depositing glass particles on a target rotating therein according to the vapor axial deposition (VAD) method (FIG. 1). A first burner 22 and a second burner 24 are arranged inside the reaction vessel 20. The first burner 22 sprays a first glass raw material 32 containing a germanium compound to synthesize germanium-containing glass particles 33. The synthesized germanium-containing glass particles 33 are sprayed on the target. The second burner 24 sprays a second glass raw material 34 not containing a germanium compound to synthesize germanium-free glass particles 35. The synthesized germanium-free glass particles 35 are sprayed on the target. The first burner 22 and the second burner 24 are arranged so that the germanium-containing glass particles 33 are deposited on the core portion of the optical fiber preform 10 and the germanium-free glass particles 35 are deposited on the cladding portion of the optical fiber preform 10.

[0032] The reaction vessel 20 has a first exhaust port 42 and a second exhaust port 44 for discharging exhaust gas containing undeposited glass particles (FIG. 1). The first exhaust port 42 and the second exhaust port 44 are arranged on the opposite side of the first burner 22 and the second burner 24 across the optical fiber preform 10. The first exhaust port 42 is arranged in the direction in which the first burner 22 injects the first glass raw material 32. Here, the "direction in which the burner injects the glass raw material" does not only refer to the direction in which the raw material injection port of the burner faces. In the case where an air inlet (not shown) is arranged in the reaction vessel 20 to facilitate the introduction of glass particles into the exhaust port, the direction refers to the direction changed from the direction in which the raw material injection port of the burner faces due to air from the air inlet. The second exhaust port 44 is arranged at a position farther away from the first burner 22 than the first exhaust port 42.

[0033] The first exhaust port 42 and the second exhaust port 44 are the inlets of the first exhaust pipe 41 and the second exhaust pipe 43, respectively, which are formed by providing a partition 46 inside one exhaust pipe (FIG. 1). That is, the first exhaust port 42 and the second exhaust port 44 are adjacent to each other with the partition 46 in between. From another perspective, the opening of one hood is divided into the first exhaust port 42 and the second exhaust port 44 by the partition 46. By dividing one exhaust pipe and arranging it as the first exhaust pipe 41 and the second exhaust pipe 43, costs can be reduced. However, the first exhaust pipe 41 and the second exhaust pipe 43 may be arranged as independent pipes, and the first exhaust port 42 and the second exhaust port 44 may be arranged separately.

[0034] Although not particularly limited, the sizes of the first exhaust port 42 and the second exhaust port 44 may be set so that their area ratio is 5:5 to 2:8. The size of the first exhaust port 42 may be 50 mm or more and 300 mm or less in width, and 100 mm or more and 300 mm or less in height. The size of the second exhaust port 44 may be 100 mm or more and 300 mm or less in width, and 100 mm or more and 600 mm or less in height.

[0035] In addition, the partition 46 may be provided with a vent hole to suppress pressure fluctuations in the first exhaust pipe 41 and the second exhaust pipe 43. The size of the vent hole may be set to a size such that the glass particles collected in each exhaust pipe do not easily move to another exhaust pipe. In addition, although the end of the partition 46 extends to the end of the first exhaust port 42 and the second exhaust port 44 in FIG. 1, the partition 46 may be shortened so that the end of the partition 46 is located farther from the optical fiber preform 10 than the end of the first exhaust port 42 and the second exhaust port 44. By shortening the partition 46, it is possible to suppress the accumulation of the glass particles on the partition 46.

[0036] The first exhaust pipe 41 is connected to the glass particle recovery section 60, and the second exhaust pipe 43 is connected to the exhaust gas treatment section 50 (FIG. 2). The exhaust gas treatment section 50 is configured to treat the exhaust gas containing glass particles discharged from the second exhaust port 44. As described later, the exhaust gas from the glass particle recovery section 60 returned to the second exhaust pipe 43 is also configured to treat it. It is preferable that the exhaust gas containing glass particles discharged from the second exhaust port 44 is sent to the exhaust gas treatment section 50 and treated in its entirety without flowing into the glass particle recovery section 60, but if it is a small amount, a part of it may flow into the glass particle recovery section 60. In addition, the manufacturing apparatus 1 is provided with a non-recovery circuit 64 for sending the exhaust gas from the exhaust pipe connecting the first exhaust port 42 and the glass particle recovery section 60 to the exhaust gas treatment section 50 without passing through the glass particle recovery section 60. By providing the non-recovery circuit 64, even if an abnormality occurs in the glass particle recovery section 60, the manufacturing of the optical fiber preform 10 in the reaction vessel 20 can be continued.

[0037] The glass particle recovery section 60 is configured to recover glass particles 70 from the exhaust gas discharged from the first exhaust port 42 (FIG. 2). The glass particle recovery section 60 includes a filter 62, and is configured to recover glass particles 70 accumulated on the filter 62 by backwashing with compressed air sent from a compressor 66. The backwashing method makes it possible to recover glass particles 70 while suppressing an increase in pressure loss in the filter 62 due to clogging. During backwashing, the circuit passing through the exhaust fan 68 is closed and the relief circuit 67 is opened.

[0038] The filter 62 is, for example, a ceramic filter or a bag filter. When a ceramic filter is used, the device can be made smaller. When fluorine is contained in the exhaust gas, the glass particles 70 can be suitably collected by using a bag filter. It is preferable to use a bag filter with excellent heat resistance. The filter 62 may also be a water-repellent filter made of a fluorine-based resin or the like. A water-repellent filter can prevent an aqueous solution such as hydrochloric acid, which dissolves the glass particles, from passing through, thereby improving the efficiency of collecting germanium.

[0039] The glass particle recovery section 60 may be configured to be temperature adjustable so as not to lower the temperature of the exhaust gas discharged from the first exhaust port 42. Although it depends on the configuration of the filter 62, if the filter is a ceramic filter, the inside of the glass particle recovery section 60 may be set to 500 degrees or more. For example, if the filter is a Teflon-based filter, the inside of the glass particle recovery section 60 may be set to 240 degrees or less. The exhaust gas discharged from the first exhaust port 42 is, for example, about 200 degrees when it enters the glass particle recovery section 60. When the temperature drops, hydrochloric acid is generated by the moisture contained in the exhaust gas, which dissolves the glass particles and may pass through the filter. Therefore, the temperature inside the glass particle recovery section 60 may be set to 100 degrees or more, preferably 150 degrees or more. A specific method of temperature adjustment may be to provide a heater in the glass particle recovery section 60.

[0040] The exhaust gas from which the glass particles 70 have been separated in the glass particle recovery section 60 is returned to the second exhaust pipe 43 and sent to the exhaust gas treatment section 50 for treatment. The exhaust gas from which the glass particles 70 have been separated in the glass particle recovery section 60 may be treated without being returned to the second exhaust pipe 43. Although the glass particle recovery section 60 is shown as a separate device from the exhaust gas treatment section 50 in FIG. 2, the exhaust gas treatment section 50 may be configured to include the glass particle recovery section 60 as part of its functions.

[0041] According to the manufacturing apparatus 1 having the above-described configuration, exhaust gas containing a large amount of glass particles containing a high concentration of germanium can be selectively recovered by the first exhaust port 42, and then the glass particles 70 can be recovered in the glass particle recovery section 60, thereby making it possible to efficiently recover germanium.

[0042] In addition, in the method for manufacturing an optical fiber preform according to this embodiment, the manufacturing apparatus 1 is used to deposit glass particles on a target rotating in a reaction vessel 20 to manufacture an optical fiber preform 10. By using the manufacturing apparatus 1, glass particles containing germanium at a high concentration are selectively collected by the first exhaust port 42, and then the glass particles 70 are collected in the glass particle collection section 60, so that the optical fiber preform 10 can be manufactured while efficiently collecting germanium.

[0043] Second Embodiment Next, details of a second embodiment of the optical fiber preform manufacturing apparatus and method of manufacturing an optical fiber preform according to the present disclosure will be described with reference to Fig. 3. Fig. 3 is a diagram showing the configuration of an optical fiber preform manufacturing apparatus 101 according to the second embodiment. The manufacturing apparatus 101 differs from the manufacturing apparatus 1 in that it is provided with two glass particle recovery sections 60, the circuit through which the exhaust gas passes is changed, and a collector section 80, which will be described later, is provided. Therefore, in the following description, parts that are common to the manufacturing apparatus 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[0044] In the manufacturing apparatus 101, a circuit is configured so that exhaust gas is supplied to each of the two glass particle recovery sections 60 from the first exhaust pipe 41 of the reaction vessel 20. The exhaust gas discharged from the two glass particle recovery sections 60 passes through a common exhaust fan 68. The manufacturing apparatus 101 includes a collector 80 that collects liquid contained in the exhaust gas discharged from the glass particle recovery section 60. The collector 80 is disposed downstream of the exhaust fan 68 in the flow direction of the exhaust gas. The collector 80 collects, for example, hydrochloric acid that can dissolve glass particles. Since hydrochloric acid may also contain germanium, by collecting such liquid with the collector 80, germanium can be recovered by performing a separate germanium recovery operation. The glass particle recovery section 60 and the collector 80 can improve the recovery amount of germanium. The collector 80 may be composed of a normal liquid trap or a cold trap. In this embodiment, the collection section 80 is positioned downstream of the exhaust fan 68 in the flow direction of the exhaust gas, but when the temperature of the exhaust gas is low, it may be positioned upstream to suppress corrosion of the exhaust fan, or it may be positioned both upstream and downstream.

[0045] The two glass particle recovery units 60 of the manufacturing apparatus 101 are configured to recover the glass particles 70 deposited on the filter 62 by backwashing. The backwashing of the two glass particle recovery units 60 can be performed independently. The manufacturing apparatus 101 is configured to be able to perform deposition of the glass particles 70 on the filter 62 and recovery of the glass particles 70 deposited on the filter 62 by backwashing in parallel. That is, one glass particle recovery unit 60 can deposit the glass particles 70 on the filter 62, and the other glass particle recovery unit 60 can recover the glass particles 70 deposited on the filter 62 by backwashing. This allows the glass particles 70 to be continuously recovered, improving the recovery efficiency of germanium.

[0046] Third embodiment Next, details of a third embodiment of the optical fiber preform manufacturing apparatus and method of manufacturing an optical fiber preform according to the present disclosure will be described with reference to Fig. 4. Fig. 4 is a diagram showing the configuration of an optical fiber preform manufacturing apparatus 201 according to the third embodiment. The manufacturing apparatus 201 differs from the manufacturing apparatus 101 in that it is provided with four reaction vessels 20 and that the circuit through which the exhaust gas passes is changed. Therefore, in the following description, parts common to the manufacturing apparatus 101 are denoted by the same reference numerals and description thereof will be omitted as appropriate.

[0047] In the manufacturing apparatus 201, a circuit is configured so that exhaust gas discharged from the first exhaust pipes 41 of the four reaction vessels 20 is collected and supplied to each of the two glass particle recovery sections 60. In the manufacturing apparatus 201, a non-recovery circuit 64 corresponding to each of the four reaction vessels 20 is provided. By providing the non-recovery circuit 64 for each of the four reaction vessels 20, the supply of glass particles from each reaction vessel 20 to the glass particle recovery section 60 can be controlled according to the operating status of the glass particle recovery section 60. EXAMPLES

[0048] Specific examples of the present disclosure will be described below, but the present disclosure is not limited to these examples. In the reaction vessel 20 shown in FIG. 1, soot (fine glass particles) was sprayed onto a target for a predetermined time to produce an optical fiber preform 10. After the completion of sooting, the soot deposited in the first exhaust pipe 41 and the second exhaust pipe 43 was collected and the concentration of germanium contained in the soot was measured. The measurement was performed by a sewage test method and an ICP emission spectrometry method. The concentration of germanium contained in the soot deposited in the first exhaust pipe 41 was 4.67% by mass, whereas the concentration of germanium contained in the soot deposited in the second exhaust pipe 43 was 0.22% by mass. This confirmed that the first exhaust port 42 can selectively collect glass particles containing germanium at a high concentration.

[0049] The present disclosure has been described above based on specific embodiments and examples, but the present invention is not limited to these examples, and is indicated by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0050] In the above-mentioned second and third embodiments, the deposition of glass particles on the filter and the recovery of the glass particles deposited on the filter by backwashing can be performed in parallel by using two glass particle recovery units 60, but the present disclosure is not limited to this embodiment. A plurality of filters 62 may be provided inside one glass particle recovery unit 60, and each filter 62 may be configured to be independently backwashed, so that the deposition of glass particles on the filter and the recovery of the glass particles deposited on the filter by backwashing can be performed in parallel. [Explanation of symbols]

[0051] 1,101,201: manufacturing equipment, 10: optical fiber base material, 20: reaction vessel, 22: first burner, 24: second burner, 32: first glass raw material, 33: germanium-containing glass particles, 34: second glass raw material, 35: germanium-free glass particles, 41: first exhaust pipe, 42: first exhaust port, 43: second exhaust pipe, 44: second exhaust port, 46: partition, 50: exhaust gas treatment unit, 60: glass particle recovery unit, 62: filter, 64: non-recovery circuit, 66: compressor, 67: relief circuit, 68: exhaust fan, 70: glass particles, 80: collection unit

Claims

1. a first burner for spraying a first glass raw material containing a germanium compound to synthesize germanium-containing glass particles; a second burner for injecting a second glass raw material not containing a germanium compound to synthesize germanium-free glass particles; a reaction vessel having the first burner and the second burner disposed therein; An apparatus for manufacturing an optical fiber preform, comprising: the reaction vessel has a first exhaust port and a second exhaust port for discharging exhaust gas containing undeposited glass particles; the first exhaust port is arranged in a direction in which the first burner sprays the first glass frit, the second exhaust port is disposed at a position farther from the first burner than the first exhaust port, an exhaust gas treatment unit for treating the exhaust gas containing glass particles discharged from the second exhaust port; a glass particle recovery section that recovers glass particles from the exhaust gas containing glass particles discharged from the first exhaust port; a collecting section for collecting liquid contained in the exhaust gas discharged from the glass particle recovery section; An apparatus for manufacturing an optical fiber preform comprising:

2. 2. The optical fiber preform manufacturing apparatus of claim 1, wherein the first exhaust port and the second exhaust port are inlets of a first exhaust pipe and a second exhaust pipe, respectively, formed by providing a partition inside a single exhaust pipe.

3. 3. The apparatus for manufacturing an optical fiber preform according to claim 1, wherein the glass particle recovery section includes a ceramic filter or a bag filter.

4. 4. The apparatus for manufacturing an optical fiber preform according to claim 1, wherein the glass particle recovery unit is configured to recover glass particles deposited on a filter by backwashing.

5. 5. The apparatus for manufacturing an optical fiber preform according to claim 1, wherein the glass particle recovery section includes a water-repellent filter.

6. 6. The optical fiber preform manufacturing apparatus according to claim 1, wherein the glass particle recovery section is configured to be capable of adjusting a temperature so as not to lower the temperature of the exhaust gas discharged from the first exhaust port.

7. 7. The optical fiber preform manufacturing apparatus according to claim 1, wherein the glass particle recovery section is provided with a filter, and is configured to recover glass particles accumulated on the filter by backwashing, so that the deposition of the glass particles on the filter and the recovery of the glass particles accumulated on the filter by backwashing can be performed in parallel.

8. 8. The optical fiber preform manufacturing apparatus according to claim 1, further comprising a non-recovery circuit for sending exhaust gas from an exhaust pipe connecting the first exhaust port and the glass particle recovery section to the exhaust gas treatment section without passing through the glass particle recovery section.

9. 9. A method for manufacturing an optical fiber preform, comprising depositing glass particles on a target rotating in a reaction vessel by using the optical fiber preform manufacturing apparatus according to claim 1 to manufacture an optical fiber preform.

Images