JP2013006767A - Apparatus and method for production of optical fiber preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for production of an optical fiber preform capable of inhibiting generation of bubbles therein.SOLUTION: The apparatus 1 for production of an optical fiber preform is provided with the burners 30 and 40 to deposit glass microparticles onto a target member 20 arranged in a reaction vessel 10, and is characterized by comprising: a booth 50 including the reaction vessel 10; a partition plate 51 to partition the interior of the booth 50 into a first space 50a and a second space 50b; and an air supplying unit 60 to supply clean air into the first space 50a. The reaction vessel 10 and the burners 30 and 40 are arranged in the first space 50a. The partition plate 51 has a plurality of through-holes 51a mutually communicating the first and second spaces 50a and 50b, an exhaust unit 70 is provided to exhaust air in the second space 50b.

Description

  The present invention relates to an optical fiber preform manufacturing apparatus and an optical fiber preform manufacturing method.

As a method for manufacturing an optical fiber preform, a VAD method and an external method are known. FIG. 7 is a vertical sectional view showing a schematic configuration of a conventional optical fiber preform manufacturing apparatus using the VAD method.
As shown in FIG. 7, the optical fiber preform manufacturing apparatus 101 deposits glass particles in the axial direction on the reaction vessel 110, the target member 120 provided in the reaction vessel 110, and the tip (downward) of the target member 120. A core burner 130 and a clad burner 140 are provided. In the conventional optical fiber preform manufacturing apparatus using the external attachment method, the core burner 130 is not provided, but only the clad burner 140 is provided.

  The target member 120 is a rod-shaped member made of, for example, quartz and extends in the vertical direction and is provided in the reaction vessel 110. The target member 120 is supported by the column 122 via the holding part 121. The column 122 is provided with a drive device (not shown) that rotates the target member 120 around its central axis and moves it in the direction of the central axis. The core burner 130 is a burner that deposits glass fine particles serving as a core in the axial direction on the tip (downward) of the target member 120 to generate the core soot S1. The clad burner 140 is a burner that generates clad soot S2 by depositing glass fine particles serving as a clad on the outer periphery of the core soot S1. The core soot S1 and the clad soot S2 are generated in the axial direction at the tip (downward) of the target member 120, whereby the optical fiber porous preform S (hereinafter simply referred to as the porous preform S) is manufactured. The produced porous preform S is subjected to a dehydration process by heating and a transparent vitrification process to become an optical fiber preform. Furthermore, an optical fiber is manufactured by drawing an optical fiber preform after providing an insufficient cladding as required.

  The manufactured optical fiber preform is required to be free from bubbles as much as possible. This is because the bubbles reduce the strength of the optical fiber after drawing and increase the light transmission loss. As a cause of the generation of bubbles in the optical fiber preform, for example, dust is mixed in the porous preform S being manufactured. In order to suppress the generation of bubbles, a reaction vessel is provided in a booth, and clean air, that is, clean air, is introduced into the booth to reduce dust in the reaction vessel (for example, Patent Document 1). reference). That is, as shown in FIG. 7, the optical fiber preform manufacturing apparatus 101 includes a booth 150 in which the reaction vessel 110 is contained, an air supply device 160 for supplying clean air into the booth 150, and the reaction vessel 110. An exhaust device 180 that exhausts air to the outside is provided. The exhaust device 180 is connected to a reaction vessel exhaust port 111 formed in the reaction vessel 110.

  Clean air is supplied into the booth 150 by the operation of the air supply device 160. An opening having a diameter larger than the diameter of the cladding burner 140 is provided on the side wall of the reaction vessel 110, and the clean air supplied into the booth 150 from the gap is inserted into the opening. Is configured to enter the reaction vessel 110. Since the air in the reaction vessel 110 is discharged to the outside by the operation of the exhaust device 180, the clean air supplied into the booth 150 is discharged to the outside through the reaction vessel 110. Therefore, the optical fiber preform manufacturing apparatus 101 including the booth 150, the air supply device 160, and the exhaust device 180 can reduce the number of dust in the reaction vessel 110. Therefore, a certain effect that the number of dusts mixed in the porous preform S can be reduced and bubbles in the optical fiber preform can be suppressed is obtained.

However, during maintenance of the optical fiber preform manufacturing apparatus 101, dust enters the booth 150 because workers enter the booth 150 and perform work. In addition, glass fine particles that could not be deposited on the target member 120 may adhere to the inner surface of the reaction vessel 110, or soot cracking may occur in the porous base material S during production, and soot powder may be generated.
For this reason, it is necessary to clean the reaction vessel 110 and the booth 150. The cleaning work is also performed when the worker enters the booth 150.

Dust such as soot powder generated during maintenance or cleaning adheres to the inner surface (particularly the floor surface 151) of the booth 150. When the production of the porous base material S is started again after the maintenance or cleaning, there is a possibility that an air flow is generated in the booth 150 due to the operation of the air supply device 160 and dust adhering to the inner surface of the booth 150 is wound up. Further, since the exhaust device 180 exhausts the air in the reaction container 110 through the reaction container exhaust port 111, an air flow from the booth 150 toward the reaction container 110 is generated. By riding on such an air flow, the rolled up dust enters the reaction vessel 110 and is mixed into the porous base material S being manufactured. That is, there has been a problem that the number of bubbles in the manufactured optical fiber preform increases after maintenance or cleaning.
In addition, since bubbles are increased in the optical fiber preform, it is necessary to resume production after a certain period of time after performing maintenance or cleaning. Therefore, there has been a problem that the processing capability of the optical fiber preform manufacturing apparatus 101 is reduced.

Japanese Patent Laid-Open No. 7-300332

  The present invention has been made in view of such a conventional situation, and can discharge the dust in the booth without passing through the reaction container, suppress the intrusion of the dust into the reaction container, and the optical fiber mother. An object of the present invention is to provide an optical fiber preform manufacturing apparatus and an optical fiber manufacturing method capable of suppressing the generation of bubbles in the material.

  An optical fiber preform manufacturing apparatus according to the present invention is an optical fiber preform manufacturing apparatus provided with a burner for depositing glass fine particles on a target member disposed in a reaction container, and a booth that contains the reaction container; A partition plate that divides the interior of the booth into a first space and a second space; and an air supply unit that supplies clean air into the first space, wherein the reaction vessel and the burner are The partition plate is disposed in the first space, and the partition plate has a plurality of through holes that communicate the first space and the second space with each other, and exhausts the air in the second space. Means are provided, and the plurality of through holes are formed over the entire surface of the partition plate.

At the time of maintenance and cleaning of the optical fiber preform manufacturing apparatus, an operator enters the booth to perform maintenance and cleaning of the reaction vessel. In addition, soot cracks may occur in the porous base material produced in the reaction vessel. In such a case, soot fine particles, that is, soot powder is generated, so it is necessary to clean the generated soot powder. . Due to maintenance and cleaning, dust such as soot powder is generated in the booth, and the generated dust adheres to the partition plate in the booth. If the production of the porous base material is started in this state and clean air is introduced into the first space from the air supply device, there is a risk that air flows in the first space and winds up dust adhering to the partition plate. is there.
However, the partition plate in the present invention has a plurality of through holes. Furthermore, exhaust means for exhausting air in the second space is provided, and by the operation of the exhaust means, air flows from the first space to the second space through the plurality of through holes. That is, most of the air in the first space can flow into the second space without passing through the reaction vessel. Even if the dust adhering to the partition plate is rolled up, the air travels from the first space to the second space, and the dust moves to the second space through the plurality of through holes. Therefore, even if the production of the porous base material is started with the dust attached to the partition plate, the number of dust entering the reaction vessel can be reduced, and the dust can be mixed into the porous base material being manufactured. Can be suppressed. As described above, there is an effect that the generation of bubbles in the optical fiber preform formed by converting the porous preform into a transparent glass by heating can be suppressed.

1 is a vertical sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus using a VAD method in a first embodiment of the present invention. It is a vertical sectional view showing a schematic structure of an optical fiber preform manufacturing apparatus using an external attachment method in the first embodiment of the present invention. It is a vertical sectional view showing a schematic structure of an optical fiber preform manufacturing apparatus using a VAD method in a second embodiment of the present invention. It is a vertical sectional view showing a schematic structure of an optical fiber preform manufacturing apparatus using a VAD method in a third embodiment of the present invention. It is a vertical sectional view showing a schematic structure of an optical fiber preform manufacturing apparatus using a VAD method in a fourth embodiment of the present invention. It is a vertical sectional view showing a schematic structure of an optical fiber preform manufacturing device using a VAD method in a fifth embodiment of the present invention. It is a vertical sectional view showing a schematic configuration of a conventional optical fiber preform manufacturing apparatus using the VAD method.

  Hereinafter, an optical fiber preform manufacturing method and an optical fiber manufacturing method according to the present invention will be described in detail with reference to the drawings. In addition, in order to make the features of the present invention easier to understand, the drawings used in the following description may show the main parts in an enlarged manner for convenience, and the dimensional ratios of the respective components are actually It is not always the same.

<First embodiment>
FIG. 1 is a vertical sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus 1 using the VAD method in the present embodiment. Note that the vertical direction in FIG. 1 is the vertical direction.
As shown in FIG. 1, the optical fiber preform manufacturing apparatus 1 is an apparatus for manufacturing an optical fiber porous preform S (hereinafter simply referred to as “porous preform S”), which includes a reaction vessel 10, Target member 20, core burner 30 (burner), clad burner 40 (burner), booth 50, air supply device 60 (air supply device), first exhaust device 70 (exhaust device), and second exhaust device 80.

  The reaction vessel 10 is a vessel containing the produced porous base material S. The reaction vessel 10 is formed with an opening (not shown), and the inside and outside of the reaction vessel 10 communicate with each other. The reaction vessel 10 is provided with a reaction vessel exhaust port 11. The reaction vessel exhaust port 11 is a vent for discharging the gas in the reaction vessel 10 toward the outside.

  The target member 20 is a rod-shaped member that extends in the vertical direction and is provided in the reaction vessel 10, and the porous base material S is manufactured in the axial direction at the tip (downward) thereof. The target member 20 is arranged so as to partially protrude from the reaction vessel 10. The target member 20 is manufactured using, for example, quartz. The target member 20 is supported by the column 22 (rigid member) via the holding portion 21. The column 22 is provided with a drive device (not shown) that rotates the target member 20 around its central axis and moves it in the direction of the central axis. The column 22 is a columnar rigid member extending in the vertical direction, and is installed outside the booth 50.

The core burner 30 deposits glass particles in the axial direction on the tip (downward) of the target member 20 to generate the core soot S1. The nozzle tip of the core burner 30 is disposed so as to protrude into the reaction vessel 10 from an opening provided in the reaction vessel 10 and is installed obliquely upward. The core burner 30 includes a glass raw material gas such as silicon tetrachloride (SiCl ₄ ) or germanium tetrachloride (GeCl ₄ ) for generating glass fine particles, a fuel gas such as hydrogen, and an oxygen gas used for combustion of the fuel gas. And a carrier gas made of an inert gas such as argon. In order to give a refractive index distribution to the optical fiber, the composition of the glass raw material gas supplied to the core burner 30 and a clad burner 40 described later is different from each other. For example, germanium tetrachloride (GeCl ₄ ) A dopant raw material is supplied. In the core burner 30, glass fine particles are generated from the glass raw material gas by oxidation reaction, hydrolysis reaction, or the like in the combustion gas generated by the combustion of the fuel gas and the oxygen gas.

The clad burner 40 is for depositing glass fine particles on the outer periphery of the core soot S1 to generate the clad soot S2. The porous base material S includes a core soot S1 and a clad soot S2. The clad burner 40 is disposed above the core burner 30 in the vertical direction. The nozzle tip of the clad burner 40 is disposed so as to protrude into the reaction vessel 10 from an opening provided in the reaction vessel 10. Similar to the core burner 30, the clad burner 40 is supplied with a glass raw material gas, a fuel gas, an oxygen gas, and a carrier gas. Examples of the glass source gas include silicon tetrachloride (SiCl ₄ ). In the cladding burner 40, glass fine particles are generated from the glass raw material gas by an oxidation reaction or the like in the combustion gas generated by the combustion of the fuel gas and oxygen gas. A plurality of the clad burners 40 may be provided.

The booth 50 contains the reaction vessel 10 and forms a space in which clean air, that is, clean air flows. The booth 50 is provided with a partition plate 51 that divides the internal space into a first space 50a and a second space 50b. In addition, the 1st space 50a and the 2nd space 50b are distribute | arranged in order toward the gravitational direction. That is, the partition plate 51 is disposed below the reaction vessel 10 in the vertical direction. The partition plate 51 is a part that serves as a scaffold for workers who enter the apparatus during maintenance or cleaning of the optical fiber preform manufacturing apparatus 1.
The partition plate 51 has a plurality of through holes 51a penetrating in the plate thickness direction. That is, the plurality of through holes 51a are arranged so as to communicate the first space 50a and the second space 50b with each other. In the present embodiment, the plurality of through holes 51 a are formed over the entire surface of the partition plate 51.

  In the first space 50a of the booth 50, the reaction vessel 10, the core burner 30, and the cladding burner 40 are arranged. Although not shown, the reaction vessel 10 is fixed to the side wall of the booth 50 or the column 22. In addition, the reaction vessel exhaust port 11 of the reaction vessel 10 is provided through the side wall of the booth 50, and is configured so that the air in the reaction vessel 10 can be discharged outside without passing through the first space 50a. The core burner 30 is fixed to the partition plate 51 via the first support member 31. Although not shown, the cladding burner 40 is fixed to the side wall of the booth 50.

  A booth exhaust port 52 is formed in the booth 50. The booth exhaust port 52 is provided in communication with the second space 50b and is a vent for discharging the gas in the second space 50b to the outside. A bottom surface 53 is arranged below the partition plate 51 in the booth 50 in the vertical direction. The bottom surface 53 forms part of the inner surface that forms the second space 50 b in the booth 50.

The air supply device 60 is a device that supplies clean air (air from which dust has been removed by a filter or the like) into the first space 50 a of the booth 50. When the air supply device 60 supplies clean air, the inside of the first space 50a is maintained at a clean degree of, for example, about class 1000. The air supply device 60 in FIG. 1 is provided on the upper surface of the booth 50 and in the vicinity of the upper surface of the side wall of the booth 50. In addition, the structure provided only in the upper surface of the booth 50, or only the upper surface vicinity in the side wall of the booth 50 may be sufficient, and the one air supply apparatus 60 provided may be sufficient.
The air supply port 61 through which the air supply device 60 supplies clean air into the first space 50a of the booth 50 is a hole opened in the top plate or side wall of the booth 50, and a plurality of air supply ports 61 may be provided. . The air supply port 61 is disposed above the core burner 30 and the clad burner 40. In other words, the flow of clean air supplied from the air supply device 60 is supplied to the first space 50a through the air supply port 61, and then passes through the position where the core burner 30 and the clad burner 40 are arranged, and further partitioned. The air supply port 61, the core burner 30, the cladding burner 40, and the partition plate 51 are arranged so as to pass through the plurality of through holes 51a in the plate 51 and be introduced into the second space 50b.

  The first exhaust device 70 is a device that exhausts air in the second space 50 b via the booth exhaust port 52.

  The second exhaust device 80 is a device that sucks air in the reaction vessel 10 through the reaction vessel exhaust port 11. In addition, since the air in the reaction vessel 10 includes combustion gas, exhaust gas, and the like generated in the core burner 30 and the clad burner 40, it is preferable to provide an exhaust gas purification device or the like in the second exhaust device 80.

Next, the manufacturing method of the optical fiber porous base material S using the optical fiber base material manufacturing apparatus 1 in this embodiment is demonstrated.
By the operation of a drive device (not shown) provided in the column 22, the target member 20 moves from the lower side in the vertical direction toward the upper side while rotating around its central axis. As the target member 20 moves, glass particles generated in the combustion gas of the core burner 30 and the clad burner 40 accumulate in the axial direction on the tip (downward) of the target member 20. The core soot S1 is generated by the glass particles supplied from the core burner 30, and the clad soot S2 is generated by the glass particles supplied from the cladding burner 40. Since the core burner 30 is provided below the cladding burner 40 in the vertical direction, the core soot S1 is first generated at the tip (downward) of the target member 20 moving from below to above, and then the core soot S1. The clad soot S2 is generated on the outer periphery of the. Therefore, the porous base material S in which the core soot S1 is disposed in the central portion and the clad soot S2 is disposed in the outer peripheral portion is manufactured.

Next, the effect | action which suppresses the number of the dust in the reaction container 10 in this embodiment is demonstrated.
Clean air is supplied from the air supply device 60 into the first space 50a. Further, the second exhaust device 80 discharges the air in the reaction vessel 10 through the reaction vessel exhaust port 11 to the outside of the booth 50 without passing through the first space 50a. Since an opening (not shown) is formed in the reaction vessel 10, a flow of clean air from the first space 50a into the reaction vessel 10 is formed.
That is, the number of dust in the reaction container 10 can be suppressed. In the case where no opening is provided due to the configuration of the apparatus, the effect of the present application is also obtained when a gap is formed in the structure of the reaction vessel 10.

At the time of maintenance and cleaning of the optical fiber preform manufacturing apparatus 1, an operator enters the booth 50 and performs maintenance or cleaning of the reaction vessel 10, the core burner 30, the cladding burner 40, and the like. Due to maintenance or cleaning, dust such as soot powder is generated in the booth 50, and the generated dust falls in the direction of gravity and adheres to the upper surface of the partition plate 51.
However, the partition plate 51 of the booth 50 in the present embodiment is formed with a plurality of through holes 51a penetrating in the plate thickness direction, and dust adhering to the upper surface of the partition plate 51 is passed through the plurality of through holes 51a. It can be dropped toward the second space 50b, and dust on the upper surface of the partition plate 51 can be easily cleaned. The dust falling toward the second space 50 b accumulates on the bottom surface 53 of the booth 50.

However, even if the partition plate 51 is cleaned, dust may remain on the upper surface of the partition plate 51. In this state, the production of the porous base material S is started, and when clean air is supplied from the air supply device 60 into the first space 50a, an air flow is generated in the first space 50a and attached to the partition plate 51. There is a risk of rolling up dust.
However, the partition plate 51 has a plurality of through holes 51a. Further, the first exhaust device 70 is connected to the booth exhaust port 52, and the air in the second space 50 b is discharged to the outside through the booth exhaust port 52 by the operation of the first exhaust device 70. When the air in the second space 50b is discharged from the booth exhaust port 52, an air flow from the first space 50a toward the second space 50b is generated through the plurality of through holes 51a. That is, the air in the first space 50a can flow into the second space 50b without passing through the reaction vessel 10. Even if the dust adhering to the upper surface of the partition plate 51 is rolled up, the air travels from the first space 50a toward the second space 50b, and the dust moves to the second space 50b through the through hole 51a. Therefore, even if the production of the porous base material S is started with the dust adhered to the partition plate 51, the number of dusts entering the reaction vessel 10 can be reduced, and the dust in the porous base material S being manufactured can be reduced. Can be prevented from being mixed. As described above, the generation of bubbles in the optical fiber preform formed by converting the porous preform S into a transparent glass by heating can be suppressed.

  Further, after the clean air flow supplied from the air supply port 61 of the air supply device 60 is supplied to the first space 50a, it passes through the position where the core burner 30 and the clad burner 40 are arranged, and further the partition plate 51. The air supply port 61, the core burner 30, the cladding burner 40, and the partition plate 51 are arranged so as to pass through the plurality of through holes 51a and be introduced into the second space 50b. Therefore, the core burner 30 and the clad burner 40 are arranged in the flow of clean air from the air supply port 61 toward the second space 50b, and dust generated around the core burner 30 and the clad burner 40 is placed in the second space 50b. Can be discharged towards.

Since the plurality of through holes 51 a are formed on the entire surface of the partition plate 51, the air flow from the first space 50 a toward the second space 50 b occurs over the entire surface of the partition plate 51. That is, the air flow in the plurality of through holes 51a is a flow parallel to the vertical direction (laminar flow) from the first space 50a to the second space 50b, and the corners between the side walls of the booth 50 and the partition plate 51 Further, air stagnation that may occur around the first support member 31 that supports the core burner 30 can be prevented, and dust can be discharged to the second space 50b over the entire surface of the partition plate 51.
Further, since air flows from the first space 50a to the second space 50b through the plurality of through holes 51a, dust accumulated on the bottom surface 53 of the booth 50 rises and enters the first space 50a again. Can be prevented.

  Further, since dust can be moved to the second space 50b through the plurality of through holes 51a using the air flow from the first space 50a to the second space 50b, there are still many in the first space 50a after maintenance and cleaning. Even in the state where the dust is present, these dusts can be quickly discharged into the second space 50b. Therefore, it is possible to shorten or eliminate a certain waiting time (time for dropping dust) that has been secured until the production of the porous base material S is started after maintenance and cleaning. That is, the processing capacity of the porous preform S using the optical fiber preform manufacturing apparatus 1 can be improved.

By the way, in the production of the porous base material S, combustion gas is generated from the core burner 30 and the cladding burner 40, and glass fine particles are generated by the heat of the combustion gas. Since this combustion gas is introduced into the reaction vessel 10, the temperature inside the reaction vessel 10 and the first space 50 a communicating with the inside of the reaction vessel 10 rises. In other words, the reaction vessel 10 and the booth 50 are heated, and deterioration due to heat proceeds, so that dust may be generated from the deteriorated reaction vessel 10 and the booth 50. The reaction vessel 10 is generally made of quartz or metal, but may be made of metal such as SUS (stainless steel) or aluminum.
Further, the booth 50, the core burner 30, and the cladding burner 40 may be deformed or loosened by being heated by the combustion gas. Due to such deformation or looseness, the direction in which the glass fine particles are supplied in the core burner 30 and the clad burner 40 is changed, which may cause variations in quality and optical characteristics in the porous base material S being manufactured and soot cracks. .
However, in the optical fiber preform manufacturing apparatus 1 of the present embodiment, air flows from the first space 50a in which the core burner 30 and the cladding burner 40 are disposed through the plurality of through holes 51a toward the second space 50b. Arise. Therefore, the heat of the combustion gas can be efficiently discharged toward the second space 50b, so that the thermal deterioration of the reaction vessel 10 and the booth 50 can be suppressed. That is, the generation of dust due to thermal degradation can be suppressed. Moreover, since the heat of combustion gas can be efficiently discharged toward the second space 50b, thermal deformation or loosening of the booth 50, the core burner 30, and the cladding burner 40 can be suppressed. That is, quality variations, soot cracks, and the like in the porous base material S can be prevented and suppressed.
Further, although a transparent member is generally used for the booth 50, a plastic plate (such as an acrylic plate or a vinyl chloride plate) that does not have high heat resistance but is inexpensive can be used for this member. The apparatus cost of the manufacturing apparatus 1 can be reduced.

  In addition, although the partition plate 51 in this embodiment is distribute | arranged to the vertical direction lower direction of the reaction container 10, it is not limited to such a structure, It partitions in the position different from the vertical direction lower direction of the reaction container 10. The structure in which the board 51 is provided may be sufficient. Even in such a configuration, the dust adhering to the partition plate 51 can be discharged from the first space 50a to the second space 50b without passing through the reaction vessel 10, so that the number of dusts entering the reaction vessel 10 can be reduced. And the generation of bubbles in the manufactured optical fiber preform can be suppressed.

The optical fiber preform manufacturing apparatus 1 in the present embodiment is a manufacturing apparatus using the VAD method, but is not limited to this, and is an optical fiber preform manufacturing apparatus using an external method. Also good. FIG. 2 is a vertical cross-sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus 1A using an external method in the present embodiment. In FIG. 2, the same elements as those in the optical fiber preform manufacturing apparatus 1 shown in FIG.
In the optical fiber preform manufacturing apparatus 1 </ b> A shown in FIG. 2, a target member 20 is provided inside the reaction vessel 10. In the external method, glass particles are deposited around the target member 20. The target member 20 may be a rod-shaped glass composed of a core or a part of a core and a clad, or a dummy member that is pulled out later. A plurality of clad burners 40 may be provided, and a dopant raw material such as germanium tetrachloride (GeCl ₄ ) may be supplied as necessary.

  As described above, according to the present embodiment, the dust in the booth 50 can be discharged without passing through the reaction container 10, the dust is prevented from entering the reaction container 10, and bubbles are generated in the optical fiber preform. There is an effect that it can be suppressed.

<Second embodiment>
FIG. 3 is a vertical sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus 1B using the VAD method in the present embodiment. In FIG. 3, the same elements as those of the first embodiment shown in FIG.
The core burner 30 in the present embodiment is disposed on the partition plate 51 via the first support member 31. Further, the first support member 31 is configured to sandwich an elastic member 32. The elastic member 32 is made of rubber or resin having elasticity, and is a member for absorbing the vibration when the partition plate 51 vibrates and suppressing the vibration of the core burner 30.

Since a plurality of through holes 51a are formed in the partition plate 51, the rigidity thereof is lower than that in the case where there is no through hole 51a. Therefore, there is a possibility that the partition plate 51 vibrates with the operation of the device (for example, the air supply device 60) provided in the booth 50. When the partition plate 51 vibrates, the core burner 30 fixed to the partition plate 51 via the first support member 31 vibrates, the glass fine particle supply direction from the core burner 30 is not stable, and the manufactured optical fiber porous material is porous. There is a risk that the quality of the base material S may vary.
However, the first support member 31 in this embodiment is provided with an elastic member 32, and even if the partition plate 51 vibrates, the elastic member 32 absorbs the vibration and prevents the core burner 30 from vibrating. Can be suppressed. Therefore, according to the present embodiment, the quality of the porous base material S can be stabilized by preventing and suppressing the vibration of the core burner 30.

<Third embodiment>
FIG. 4 is a vertical sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus 1C using the VAD method in the present embodiment. In FIG. 4, the same elements as those of the first embodiment shown in FIG.
The core burner 30 in the present embodiment is fixed to the bottom surface 53 of the booth 50 via the second support member 33. The second support member 33 includes a plurality of rod-like members extending in the vertical direction, and the rod-like members are inserted through the through holes 51 a of the partition plate 51 in a non-contact state. That is, the second support member 33 is arranged in a non-contact state with the partition plate 51.
Further, a space indicated by a symbol h is formed between the core burner 30 and the partition plate 51.

Since the second support member 33 is arranged in a non-contact state with the partition plate 51, even if the partition plate 51 vibrates, the vibration is not transmitted to the second support member 33, resulting in the vibration of the core burner 30. Can be prevented. Therefore, according to the present embodiment, vibrations of the core burner 30 can be prevented, and the quality of the porous base material S can be stabilized.
In addition, since the gap h is formed between the core burner 30 and the partition plate 51, there is an effect that cleaning around the core burner 30 is facilitated. Furthermore, it is possible to suppress the stagnation in the air flow from the first space 50 a to the second space 50 b around the core burner 30, and to prevent / suppress the accumulation of dust around the core burner 30.
In addition, although the 2nd support member 33 in this embodiment is being fixed to the bottom face 53, it is not limited to this, The structure fixed to the side wall of the booth 50 may be sufficient.

<Fourth embodiment>
FIG. 5 is a vertical sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus 1D using the VAD method in the present embodiment. In FIG. 5, the same elements as those of the first embodiment shown in FIG.
The core burner 30 in the present embodiment is fixed to the column 22 disposed outside the booth 50 via the third support member 34. Although not shown, the third support member 34 is provided through the side wall of the booth 50. The third support member 34 is arranged in a non-contact state with the partition plate 51.
Further, a space indicated by a symbol h is formed between the core burner 30 and the partition plate 51.

Since the third support member 34 is arranged in a non-contact state with the partition plate 51, even if the partition plate 51 vibrates, the vibration is not transmitted to the third support member 34, resulting in the vibration of the core burner 30. Can be prevented. Therefore, according to the present embodiment, vibrations of the core burner 30 can be prevented, and the quality of the porous base material S can be stabilized.
In addition, since the gap h is formed between the core burner 30 and the partition plate 51, there is an effect that cleaning around the core burner 30 is facilitated. Furthermore, it is possible to suppress the stagnation in the air flow from the first space 50 a to the second space 50 b around the core burner 30, and to prevent / suppress the accumulation of dust around the core burner 30.

<Fifth embodiment>
FIG. 6 is a vertical cross-sectional view showing a schematic configuration of an optical fiber preform manufacturing apparatus 1E using the VAD method in the present embodiment. In FIG. 6, the same elements as those in the first embodiment shown in FIG.
The core burner 30 in the present embodiment is fixed to the outer surface of the reaction vessel 10 via the fourth support member 35. The reaction vessel 10 is fixed to the side wall of the booth 50 or the column 22 and is arranged in a non-contact state with the partition plate 51. Therefore, the fourth support member 35 is arranged in a non-contact state with the partition plate 51.
Further, a space indicated by a symbol h is formed between the core burner 30 and the partition plate 51.

Since the fourth support member 35 is arranged in a non-contact state with the partition plate 51, even if the partition plate 51 vibrates, the vibration is not transmitted to the fourth support member 35, resulting in the vibration of the core burner 30. Can be prevented. Therefore, according to the present embodiment, vibrations of the core burner 30 can be prevented, and the quality of the porous base material S can be stabilized.
In addition, since the gap h is formed between the core burner 30 and the partition plate 51, there is an effect that cleaning around the core burner 30 is facilitated. Furthermore, it is possible to suppress the stagnation in the air flow from the first space 50 a to the second space 50 b around the core burner 30, and to prevent / suppress the accumulation of dust around the core burner 30.

<Example>
In each apparatus shown in Table 1, a soot base material was manufactured and then subjected to dehydration and transparent vitrification treatment to obtain an optical fiber base material having an outer diameter of 100 mm and an effective length of 1000 mm. The time from cleaning to the start of production was immediately and 2 hours later, 5 base materials were manufactured, and the average number of bubbles of 5 base materials was counted. In addition, the number of bubbles in the base material produced immediately after soot cracking was counted. The maximum temperature at the side wall of the booth 50 is also measured. Further, the fluctuation of MFD (Mode Field Diameter) expected when the manufactured base material is coated with a clad of a certain magnification to make an optical fiber was estimated from the measurement result of the refractive index distribution of the base material. This was based on Comparative Example 1.
As shown in Table 1, the supply amount of clean air from the air supply device 60 is adjusted.
This was based on Comparative Example 1.

Consider the above embodiment.
When Example 1 is compared with Comparative Example 1 and Comparative Example 2, even if the supply amount of clean air is increased, the MFD fluctuation does not increase, but rather decreases, and the effect of heat countermeasures can be seen. Air bubbles in the base material manufactured immediately after cleaning and in the base material manufactured immediately after soot cracking are reduced, and the effect of air bubble reduction is also seen. Therefore, the effect of reducing bubbles can be increased without affecting the deposition of glass particles.
Further, in Comparative Example 1, when about 100 base materials were generated, it was observed that the side walls of the booth 50 were distorted by heat, and the number of bubbles in the base material showed an increasing tendency. When the cleanliness in the booth 50 was measured, it was less than class 1000, but there were about class 3500, and the cleanliness was lowered. However, in Example 1, even when 100 base materials were generated, the distortion of the side wall of the booth 50 was not observed, and the number of bubbles did not increase.

Comparing Example 2 and Example 3, the opening area of the partition plate 51 (opening area of the through hole 51a) is wide (opening area ratio 36% → 74% (opening area of the through hole 51a with respect to the area of the partition plate 51). When the clean air flow rate is increased, the MFD fluctuation tends to be slightly larger in the second embodiment than in the first embodiment, but the MFD fluctuation is small in the third embodiment.
Even if the opening area of the partition plate 51 is increased and the clean air flow rate is increased, the characteristic fluctuation due to the vibration of the core burner does not occur.

When Example 2 and Example 4 are compared, if the opening area of the partition plate 51 is widened to increase the amount of clean air ventilation, Example 2 tends to have a slightly larger MFD variation than Example 1. However, in Example 4, the MFD fluctuation is small.
Even if the opening area of the partition plate 51 is increased and the amount of clean air flow is increased, the characteristic variation due to the vibration of the core burner 30 does not occur.

  According to Example 5, the bubble reduction effect is further increased.

  As mentioned above, although the optical fiber preform manufacturing apparatus and the optical fiber preform manufacturing method have been described, the present invention is not limited to this, and can be appropriately changed without departing from the spirit of the invention.

  The present invention is widely applicable to an optical fiber preform manufacturing apparatus and an optical fiber preform manufacturing method.

  DESCRIPTION OF SYMBOLS 1 Optical fiber preform manufacturing apparatus, 10 Reaction container, 20 Target member, 22 Column (rigid member), 30 Core burner (burner), 31 1st support member, 32 Elastic member, 33 2nd support member, 34 3rd support member , 35 fourth support member, 40 clad burner (burner), 50 booth, 50a first space, 50b second space, 51 partition plate, 51a through hole, 60 air supply device (air supply means), 61 air supply port, 70 First exhaust device (exhaust means)

Claims (8)

An optical fiber preform manufacturing apparatus comprising a burner for depositing glass particles on a target member arranged in a reaction vessel,
A booth containing the reaction vessel;
A partition plate that divides the interior of the booth into a first space and a second space;
An air supply means for supplying clean air into the first space,
The reaction vessel and the burner are arranged in the first space,
The partition plate has a plurality of through holes that communicate the first space and the second space with each other;
Exhaust means for exhausting air in the second space is provided;
The apparatus for manufacturing an optical fiber preform, wherein the plurality of through holes are formed over the entire surface of the partition plate.   2. The optical fiber preform manufacturing apparatus according to claim 1, wherein the first space and the second space are sequentially arranged in the direction of gravity. After the air flow is supplied from the air supply means to the first space through the air supply port, the air flow passes through the position where the burner is disposed, and further passes through the plurality of through holes in the partition plate. As introduced into the second space,
The optical fiber preform manufacturing apparatus according to claim 1 or 2, wherein the air supply port, the burner, and the partition plate are arranged. A plurality of the burners;
A part of the burner is arranged on the partition plate via a first support member,
The optical fiber preform manufacturing apparatus according to any one of claims 1 to 3, wherein the first support member includes an elastic member. A plurality of the burners;
4. The light according to claim 1, wherein a part of the burner is fixed to an inner surface of the booth that forms the second space via a second support member. 5. Fiber preform manufacturing equipment. A plurality of the burners;
4. The optical fiber according to claim 1, wherein a part of the burner is fixed to a rigid member disposed outside the booth via a third support member. 5. Base material manufacturing equipment. A plurality of the burners;
4. The optical fiber preform manufacturing apparatus according to claim 1, wherein a part of the burner is fixed to an outer surface of the reaction vessel via a fourth support member. 5. Using the optical fiber preform manufacturing apparatus according to any one of claims 1 to 7,
The air is supplied to the first space, then passed through the position where the burner is disposed, and further passed through the plurality of through holes in the partition plate and introduced into the second space. An optical fiber preform manufacturing method comprising manufacturing a fiber preform.

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