Glass particle deposit manufacturing equipment

Abstract

To provide an apparatus for manufacturing a glass fine particle deposit, capable of preventing a burner for preparing the glass fine particle deposit from deteriorating and damaging.SOLUTION: An apparatus for manufacturing a glass fine particle deposit includes a burner for forming glass particles for preparing the glass fine particle deposit by supplying a glass raw material into flame. The burner includes a metal burner body, and a tubular hood for controlling influence on an air current to the flame formed by the burner body. The hood is attached to the burner body so as to extend in an ejection direction of ejecting the glass raw material from the burner body. The hood is formed of a material having a thermal expansion coefficient larger than that of silica glass and equal to or less than that of metal forming the burner body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus for manufacturing a soot glass deposit body. [Background technology]

[0002] Patent Document 1 discloses an apparatus for manufacturing a porous preform for optical fiber, in which an airflow regulating member for regulating the influence of airflow on the flame is attached to the outer periphery of the tip of a burner. Patent Document 2 discloses a metal burner for producing porous glass made of a heat-resistant alloy material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-172545 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-076982 Summary of the Invention [Problem to be solved by the invention]

[0004] There is room for improvement in extending the life of the hood, which serves as an airflow restricting member attached to a burner for producing an optical fiber preform as disclosed in Patent Documents 1 and 2.

[0005] Therefore, an object of the present disclosure is to provide a soot glass deposit body manufacturing apparatus that can prevent deterioration and damage to a burner used to manufacture the soot glass deposit body. [Means for solving the problem]

[0006] An apparatus for manufacturing a soot glass deposit body according to one aspect of the present disclosure includes: 1. An apparatus for producing a soot glass deposit body, comprising: a burner for generating glass soot for producing a soot glass deposit body by supplying a glass raw material into a flame, The burner includes a metal burner body and a tubular hood for regulating the influence of airflow on the flame formed by the burner body; the hood is attached to the burner body so as to extend in a jetting direction in which the glass raw material jets from the burner body, The hood is made of a material having a thermal expansion coefficient greater than that of quartz glass and less than or equal to that of the metal forming the burner body. [Effects of the Invention]

[0007] According to the above configuration, it is possible to provide an apparatus for manufacturing a soot glass deposit body that can prevent deterioration and damage to the burner used to manufacture the soot glass deposit body. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of a soot glass deposit manufacturing apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a core synthesis burner used in the production apparatus shown in FIG. [Figure 3] FIG. 3 is a perspective view showing a bracket and a hood that constitute the core synthesis burner. [Figure 4] FIG. 4 is a diagram showing a first modified example of the core synthesis burner. [Figure 5] FIG. 5 is a diagram showing a second modified example of the core synthesis burner. [Figure 6] FIG. 6 is a diagram showing a conventional example of a core synthesis burner. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Description of Embodiments of the Present Disclosure) First, embodiments of the present disclosure will be listed and described. An apparatus for manufacturing a soot glass deposit body according to one aspect of the present disclosure includes: (1) A glass soot deposit manufacturing apparatus including a burner for generating glass soot for producing a glass soot deposit by supplying glass raw material into a flame, The burner includes a metal burner body and a tubular hood for regulating the influence of airflow on the flame formed by the burner body; the hood is attached to the burner body so as to extend in a jetting direction in which the glass raw material jets from the burner body, The hood is made of a material having a thermal expansion coefficient greater than that of quartz glass and less than or equal to that of the metal forming the burner body. According to the above configuration, damage to the hood due to the difference in thermal expansion coefficient with the metal burner body is unlikely to occur, and therefore it is possible to provide an apparatus for manufacturing a glass soot deposit body that can prevent deterioration and damage to the burner used to manufacture the glass soot deposit body.

[0010] (2) The material forming the hood may be either silicon carbide or silicon nitride. The above configuration prevents damage to the hood due to differences in the thermal expansion coefficient between the hood and the metal forming the burner body. Also, by suppressing adhesion of glass particles to the inner wall surface of the hood, the generation of surface irregularities on the inner wall surface can be prevented, and deformation of the deposition surface of the glass particle deposit body due to these surface irregularities can be suppressed.

[0011] (3) The hood is a cylindrical portion extending in the ejection direction; The nozzle may include a tapered portion located closer to the ejection direction than the cylindrical portion and having an inner diameter that increases toward the ejection direction. According to the above-mentioned configuration, the range of the flame impinging on the deposition surface of the glass soot deposit body can be appropriately expanded, and the bulk density of the glass soot deposit body can be further increased. In addition, since the distance between the tapered portion of the hood and the flame ejected from the tapered portion can be increased, deterioration of the tip of the tapered portion of the hood due to the flame can be suppressed.

[0012] (4) The hood may be detachable from the burner body. According to the above configuration, if the hood deteriorates due to the influence of a flame or the like, the deteriorated hood can be removed and replaced with a new hood. In other words, if the hood deteriorates, it is only necessary to replace the hood and not the burner body, which reduces costs.

[0013] (5) A flange portion protruding radially outward from the end of the hood is formed, The flange portion may be detachably fixed to the burner body. According to the above-described configuration, the hood is firmly fixed to the burner body by the flange portion formed on the hood, which prevents the hood from shifting in position relative to the burner body, thereby enabling the production of a stable soot glass deposit body without distortion.

[0014] (6) The flange portion may be fixed to the burner body by a metal bolt. According to the above configuration, the use of metal bolts minimizes the effects of thermal expansion, making it difficult for the fixation between the burner body and the hood to loosen, and more reliably preventing the hood from shifting out of position relative to the burner body.

[0015] (7) Further comprising a fixing jig that is detachably fixed to the burner body, The hood may be fixed to the burner body by clamping the flange portion between the burner body and the fixing jig with the outer surface of the flange portion covered by the fixing jig. According to the above configuration, the hood can be easily detached from the burner body, making it easy to disassemble the burner for cleaning.

[0016] (8) The burner body and the hood may be used in a core synthesis burner for the VAD method. The configuration of the present disclosure is preferably applied to a core synthesis burner, which has a large effect on optical fiber characteristics.

[0017] (Details of the embodiments of the present disclosure) Specific examples of a soot glass deposit manufacturing apparatus according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0018] FIG. 1 is a configuration diagram showing an example of a soot glass deposit manufacturing apparatus according to an embodiment of the present disclosure. In the following embodiments, the VAD (Vapor Phase Axial Deposition) method will be described as an example of a method for producing a glass soot deposit body, but the method is not limited to the VAD method. Similar to the VAD method, this embodiment can also be applied to a method for depositing glass soot from a glass raw material by utilizing a flame pyrolysis reaction, such as an OVD (Outside Vapor Phase Deposition) method.

[0019] As shown in FIG. 1, the apparatus 1 for manufacturing a glass soot deposit of this embodiment includes a reaction vessel 2. A support rod 3 is suspended from above the reaction vessel 2 inside the vessel, and a dummy glass rod (starting rod) 4 is attached to the underside of the support rod 3. Glass soot is deposited on the dummy glass rod 4 to form a glass soot deposit (optical fiber preform) M. The upper end of the support rod 3 is held by an elevator device 10, which moves the support rod 3 up and down as it rotates. The elevator device 10 is controlled by a control unit 20. An exhaust pipe 5 is attached to the side wall of the reaction vessel 2.

[0020] A core synthesis burner 6 and a clad synthesis burner 7 are provided at the bottom inside the reaction vessel 2. The tips of the core synthesis burner 6 and the clad synthesis burner 7 protrude into the reaction vessel 2. The core synthesis burner 6 and the clad synthesis burner 7 are supplied with raw material gas, flame-forming gas (flammable gas and combustion-supporting gas), etc., respectively. The flow rates of the gases supplied to the core synthesis burner 6 and the clad synthesis burner 7 are controlled by an MFC (Mass Flow Controller) 21. The MFC 21 controls the gas supply amount based on control signals sent from the control unit 20. Liquid raw material contained in a raw material container 11 is vaporized and supplied to the core synthesis burner 6 and the clad synthesis burner 7 as raw material gas. The flame-forming gas is supplied to the core synthesis burner 6 and the clad synthesis burner 7 from a gas supply device 12.

[0021] Fig. 2 is a partial cross-sectional view in the length direction of the core synthesis burner 6. Fig. 3 is a perspective view showing a bracket 63 and a hood 64 that constitute the core synthesis burner 6. 2 and 3, the core synthesis burner 6 includes a core synthesis burner body 61 (an example of a burner body) and a hood 64 that is detachably fixed to the burner body 61. The burner body 61 has a burner base 62 and a bracket 63 that is attached to the periphery of the burner base 62.

[0022] Although the internal structure of the burner base 62 is not shown, it is, for example, a component in which a plurality of gas outlet pipes of different diameters are concentrically arranged. That is, the core synthesis burner 6 is preferably, for example, a multi-tube burner in which at least a central port for flowing glass raw material and at least one gas outlet port for a flammable gas or a combustion supporting gas are concentrically arranged so as to surround the central port. The burner base 62 is formed so that a predetermined range of a tip portion 62a on the gas outlet side (right side in FIG. 2) has a smaller diameter than a base portion 62b. That is, a step portion 62c is formed at the boundary between the tip portion 62a and the base portion 62b of the burner base 62. The burner base 62 is, for example, a metal component made of stainless steel or the like.

[0023] The bracket 63 is a member configured in a substantially cylindrical shape. The inner diameter of the bracket 63 is formed so as to be slightly larger than the outer diameter of the tip portion 62a of the burner base 62. On the other hand, the inner diameter of the bracket 63 is formed so as to be smaller than the outer diameter of the root portion 62b of the burner base 62. The bracket 63 is attached to the periphery of the tip portion 62a of the burner base 62. Flange portions 65, 66 that protrude radially outward are provided at both ends of the bracket 63. The bracket 63 is fixed to the burner base 62 by bolting one flange portion 65 of the flange portions 65, 66 to a step portion 62c of the burner base 62 with a bolt 68. The bracket 63 and the bolt 68 are metal members made of, for example, stainless steel, titanium, or the like.

[0024] The hood 64 is a tubular member for regulating the influence of the airflow of the flame formed by the core synthesis burner 6. The hood 64 includes a cylindrical portion 64A and a tapered portion 64B. The cylindrical portion 64A is formed so as to extend in the ejection direction of the glass frit ejected from the burner body 61 when the hood 64 is attached to the burner body 61. The inner diameter of the cylindrical portion 64A is formed so as to be slightly larger than the outer diameter of the tip portion 62a of the burner base 62. This configuration makes it easy to fix the burner base 62 and the hood 64 with the tip portion 62a of the burner base 62 inserted inside the cylindrical portion 64A. The cylindrical portion 64A is attached around the tip portion 62a of the burner base 62 so as to have the same central axis as the central axis of the burner base 62.

[0025] The tapered portion 64B is formed to extend from the end of the cylindrical portion 64A on the ejection direction side toward the ejection direction side. The tapered portion 64B is formed so that the inner diameter increases toward the tip, which is on the ejection direction side. An opening 64C is formed at the tip of the tapered portion 64B. The glass raw material gas and the like ejected from the burner body 61 passes through the inside of the cylindrical portion 64A and the tapered portion 64B and is ejected from the opening 64C to the outside of the hood 64.

[0026] A flange portion 67 protruding radially outward is provided at the end of the cylindrical portion 64A opposite to the tapered portion 64B (the end on the left side in FIG. 2). The hood 64 is detachably fixed to the burner body 61 by fastening the flange portion 67 to the flange portion 66 of the bracket 63 with bolts 69.

[0027] In this example, the material for forming the hood 64 is preferably, for example, silicon carbide (SiC) or silicon nitride (Si3N4) from the viewpoint of high heat resistance, and silicon nitride is more preferable from the viewpoint of thermal shock resistance. Note that the material for the hood 64 is not limited to these, and from the viewpoint of thermal expansion, other materials having a thermal expansion coefficient close to that of the metal, such as stainless steel, that constitutes the burner base 62 and the bracket 63 can be used. Specifically, the material for the hood 64 can be, for example, a material having a thermal expansion coefficient that is greater than that of quartz glass and less than that of the metal that constitutes the burner base 62 and the bracket 63. The thermal expansion coefficient of quartz glass, which has been conventionally used as the material for the hood 64 (0.5 × 10 -6 / ℃), and the thermal expansion coefficient of metals such as stainless steel (9×10 -6 ~15×10 -6 It is preferable to use a material with a thermal expansion coefficient of 3.7 × 10 / °C or less. The thermal expansion coefficient of silicon carbide is 3.7 × 10 -6 ~4.6×10 -6 / ℃, and the thermal expansion coefficient of silicon nitride is 2.4×10 -6 ~3.5×10 -6 / ° C. For example, the hood 64 may be made of alumina (aluminum oxide) or zirconia (zirconium oxide).

[0028] In this example, the hood 64 is made of, for example, silicon nitride, so the cylindrical portion 64A and tapered portion 64B can be made thicker than in the case of a hood made of quartz glass. The cylindrical portion 64A and tapered portion 64B of the hood 64 each have a thickness of approximately 5 mm. The bolts 69 used to attach the hood 64 to the bracket 63 are metal members made of, for example, stainless steel or titanium.

[0029] The fixing surface of the bracket 63 to which the flange portion 67 of the hood 64 is fixed, i.e., the outer surface 66a (the right end in FIG. 2 ) of the flange portion 66 of the bracket 63, is located at a position spaced a predetermined distance L from the gas ejection side end 62d of the burner base 62 toward the root portion 62b in the axial direction of the burner base 62. The predetermined distance L is preferably 0 mm or more and 100 mm or less. More preferably, the predetermined distance L is 50 mm. A gasket 70 made of carbon or fluororesin, for example, Teflon (registered trademark), is provided between the flange portion 67 of the hood 64 and the fixing surface 66a of the flange portion 66 of the bracket 63. The gasket 70 may be formed, for example, in a ring shape.

[0030] (Method of manufacturing glass particle deposit body) As shown in Figure 1, the manufacturing apparatus 1 for glass particle deposit (optical fiber preform) M configured as described above supplies glass raw material to a core synthesis burner 6 and a cladding synthesis burner 7, generates glass particles by oxidation or hydrolysis reaction in the flames formed by each burner, and deposits the glass particles on the tip or outer periphery of a rotating dummy glass rod 4 to produce the glass particle deposit M.

[0031] A glass raw material gas and a flame-forming gas are supplied to the core synthesis burner 6. The glass raw material gas contains, for example, silicon tetrachloride (SiCl4) or siloxane. The glass raw material gas preferably contains, for example, germanium tetrachloride as a dopant. When silicon tetrachloride and germanium tetrachloride are used as the glass raw material gas, glass particles mainly composed of silica (SiO2) and germanium dioxide (GeO2) are generated in the flame of the core synthesis burner 6. The flame-forming gas is, for example, an oxyhydrogen gas, which contains hydrogen, a flammable gas, and oxygen, a combustion-supporting gas.

[0032] The glass raw material gas supplied to the core synthesis burner 6 is ejected from the burner body 61, and together with the flame formed by the flame formation gas, passes through the cylindrical portion 64A and the tapered portion 64B of the hood 64 and is ejected from the opening 64C to the outside of the hood 64. The glass particles generated in this process are deposited on the deposition surface in the ejection direction.

[0033] The deposition surface refers to the surface on the dummy glass rod 4 at the beginning of the deposition process, and after the glass particle deposit M has been deposited on the dummy glass rod 4, it refers to the surface on the glass particle deposit M. In the region of the glass particle deposit M where a sufficient amount of glass particles that will become the core have been deposited, glass particles that will become the clad are later deposited by the clad synthesis burner 7.

[0034] As described above, the manufacturing apparatus 1 for a glass soot deposit M according to this embodiment includes a core synthesis burner 6 that supplies glass raw material into a flame to generate glass soot for producing the glass soot deposit M. The core synthesis burner 6 includes a metal burner body 61 and a tubular hood 64 for regulating the influence of airflow on the flame formed by the burner body 61. The hood 64 is attached to the burner body 61 so as to extend from the burner body 61 in the ejection direction of the glass raw material. The hood 64 is made of a material (e.g., silicon carbide, silicon nitride, alumina, or zirconia) having a thermal expansion coefficient that is greater than that of quartz glass and less than or equal to that of the metal forming the burner body 61.

[0035] While it is possible to use heat-resistant quartz glass as a material for forming the hood, quartz glass is vulnerable to impacts and breaks relatively frequently. Furthermore, when a quartz glass hood is fixed to a metal burner body, cracks are likely to occur in the hood, especially in the flange area, due to the difference in thermal expansion coefficients between quartz glass and metal. In contrast, according to the configuration of this embodiment, the hood 64 is formed using a material having a thermal expansion coefficient closer to that of the metal material forming the burner body 61 than quartz glass, such as silicon carbide, silicon nitride, alumina, or zirconia. That is, the core synthesis burner 6 is formed using a hood 64 that is more shock resistant than a quartz glass hood and is less susceptible to cracks in the flange portion 67 due to the difference in thermal expansion coefficient with the metal burner body 61. Therefore, it is possible to prevent deterioration and damage to the hood 64 during the manufacturing process of the glass soot deposit M, and it is possible to achieve a longer life for the core synthesis burner 6.

[0036] Furthermore, when a quartz glass hood is used, some of the glass particles generated by the burner body may adhere to the inner wall surface of the hood as excess soot, causing surface irregularities on the inner wall surface. The surface irregularities caused by the adhesion of soot to the inner wall surface may change the ejection direction and amount of the flame and glass particles, which may lead to deformation of the deposition surface of the glass particle deposit body M. In contrast, when the hood 64 is formed using silicon carbide, silicon nitride, alumina, or zirconia, as in this embodiment, the surface roughness of the inner wall surface of the hood 64 is smaller than when quartz glass is used. As a result, less soot adheres to the inner wall surface of the hood 64. As a result, the inner wall surface of the hood 64 does not change over time, such as becoming uneven, and deformation of the deposition surface of the glass soot deposit M due to soot adhesion to the hood 64 can be prevented.

[0037] Furthermore, in the manufacturing apparatus 1 according to this embodiment, the hood 64 includes a cylindrical portion 64A extending in the ejection direction of the glass soot, and a tapered portion 64B located on the tip (ejection direction) side of the cylindrical portion 64A and having an inner diameter that increases toward the tip. This configuration allows the range of the flame that strikes the deposition surface of the glass soot deposit M to be appropriately expanded, thereby increasing the bulk density of the glass soot deposit M. Furthermore, the distance between the opening 64C of the hood 64 and the flame ejected from the opening 64C can be increased, thereby preventing the vicinity of the opening 64C from being deteriorated by the flame.

[0038] Moreover, the hood 64 according to this embodiment is detachable from the burner body 61, specifically the bracket 63. With this configuration, if the hood 64 deteriorates due to the influence of a flame or the like, the deteriorated hood 64 can be removed and replaced with a new hood 64. In other words, if the hood 64 deteriorates, it is only necessary to replace the hood 64, rather than the entire core synthesis burner 6, which allows for cost reduction.

[0039] Incidentally, a conventional method for fixing the hood to the burner body has been to attach tape 310 or the like to the burner body 301 and the hood 302, as shown in Fig. 6. However, the fixing force of the tape 310 is not always sufficient, and for example, when cleaning dirt adhering to the tip of the burner body 301 or the hood 302, the attachment angle or attachment position of the hood 302 may shift. If the attachment position of the hood 302 changes, the direction of the glass particles ejected from the burner body 301 also changes, making it difficult to produce a stable glass particle deposit body M without distortion.

[0040] In contrast, in the manufacturing apparatus 1 according to the above embodiment, a flange 67 that protrudes radially outward from the hood 64 is formed on the end of the cylindrical portion 64A of the hood 64, and the flange 67 is detachably fixed to the burner body 61. In this way, by fixing the flange 67 formed on the cylindrical portion 64A of the hood 64 to the bracket 63 of the burner body 61, the hood 64 can be firmly fixed to the burner body 61. Therefore, it is possible to prevent the hood 64 from shifting in position relative to the burner body 61. This makes it possible to reliably suppress the influence of airflow on the flame of the core synthesis burner 6 in the reaction vessel 2, and to produce a stable glass soot deposit body M without distortion.

[0041] Furthermore, in the manufacturing apparatus 1, the flange portion 67 of the hood 64 is fixed to the burner body 61 with metal bolts 69. With this configuration, the hood 64 can be reliably fixed to the burner body 61 without loosening. In addition, since the generation of impurities due to bolt corrosion can be prevented, the adhesion of impurities to the soot glass deposit M can be suppressed.

[0042] In the embodiment shown in FIGS. 2 and 3, the core synthesis burner 6 has been described, but the clad synthesis burner 7 can also be configured in the same manner as in this embodiment.

[0043] (Example) The present disclosure will be described in more detail below with reference to examples and comparative examples according to the present disclosure. However, the present disclosure is not limited to the following examples.

[0044] (Production Example 1) In Production Example 1, a glass soot deposit was produced using a conventional core synthesis burner with a quartz glass hood attached to a metal burner body. The glass raw material gas used was a gas containing silicon tetrachloride and germanium tetrachloride. The flame-forming gas used was hydrogen gas and oxygen gas.

[0045] (Production Example 2) As Production Example 2, a soot glass deposit was produced using a core synthesis burner according to an embodiment of the present disclosure, in which a hood made of silicon nitride (Si3N4) was attached to a metal burner body. The soot glass deposit was produced using the same method as Production Example 1, except that a hood made of silicon nitride was used instead of a quartz glass hood.

[0046] (evaluation) In Production Examples 1 and 2, the percentage of glass soot deposit bodies manufactured whose deposition surfaces had deformations exceeding a predetermined range (deformation incidence) and the number of hood breakages per year in one glass soot deposit body manufacturing apparatus equipped with a core synthesis burner were evaluated. First, the deformation incidence rate of the deposition surfaces of the glass soot deposit bodies was 5.5% in Production Example 1 and 1.5% in Production Example 2. Furthermore, the number of hood breakages was 0.9 / unit per year in Production Example 1 and 0 / unit per year in Production Example 2. Thus, it was confirmed that the deformation incidence rate of glass soot deposit bodies and the breakage incidence rate of hoods can be significantly reduced by using a material having a thermal expansion coefficient closer to that of metal, such as silicon nitride, instead of quartz glass, as the material for forming the hood.

[0047] (First Modification) Next, a first modified example of the core synthesis burner will be described with reference to FIG. In the core synthesis burner 6 in the above-described embodiment, a bracket 63 is provided to fix the hood 64 to the burner body 61, and the hood 64 is bolted to the bracket 63, but this configuration is not limited to this. For example, the hood may be bolted directly to the burner base without a bracket.

[0048] Fig. 4 is a cross-sectional view showing the configuration of a core synthesis burner 106 according to a first modified example. As shown in Fig. 4, the core synthesis burner 106 comprises a burner body 161 for core synthesis and a hood 164 that is detachable from the burner body 161. The burner body 161 has a burner base 162. The burner base 162 is, for example, a metal member.

[0049] The hood 164 is fixed to the burner base 162 (burner body 161) by fastening a flange portion 167 to a step portion 162c of the burner base 162 with bolts 169. The hood 164 is made of, for example, silicon nitride (Si3N4). The bolts 169 are made of, for example, stainless steel or titanium.

[0050] In the configuration of the core synthesis burner 106 of this modified example, the flange portion 167 of the hood 164 is directly fixed to the burner base 162 of the burner body 161. Even with this configuration, the same effects as when the core synthesis burner 6 of the above embodiment is used can be obtained.

[0051] (Second Modification) Next, a second modified example of the core synthesis burner will be described with reference to FIG. Fig. 5 is a cross-sectional view showing the configuration of a core synthesis burner 206 according to a second modified example. As shown in Fig. 5, the core synthesis burner 206 includes a burner body 261 for core synthesis, a hood 264 that is detachable from the burner body 261, and a fixing jig 81 for fixing the hood 264 to the burner body 261.

[0052] A flange portion 91 protruding radially outward is provided at the end portion on the gas ejection side (the right side in FIG. 5) of the burner body 261. The outer peripheral surface of the flange portion 91 is threaded.

[0053] The hood 264 is formed of, for example, silicon nitride, similar to the hood 64 of the above embodiment. One end (the left end in FIG. 5) of the hood 264 is provided with a flange portion 267 that protrudes radially outward. The other end (the right end in FIG. 5) of the hood 264 is not enlarged in diameter, unlike the hood 64 of the above embodiment.

[0054] The fixing jig 81 is a cylindrical member made of, for example, the same metal as the burner body 261. The fixing jig 81 has a bottom 82 on one end side along the axial direction of the burner body 261. A hole 83 is formed in the center of the bottom 82. The diameter of the hole 83 is formed to be slightly larger than the outer diameter of the cylindrical portion of the hood 264 other than the flange portion 267. The inner peripheral surface on the other end side of the fixing jig 81 is threaded. The fixing jig 81 is attached to the periphery of the flange portion 91 of the burner body 261 by screwing it into the flange portion 91. In other words, the fixing jig 81 is detachably fixed to the burner body 261.

[0055] In the second modified example, the hood 264 is attached to the burner body 261 as follows. First, the hood 264 is inserted into the hole 83 of the fixing jig 81 from the end opposite to the side where the flange portion 267 is provided. In this state, the gas ejection side end of the burner body 261 is inserted into the hood 264, and the fixing jig 81 is screwed onto the flange portion 91 of the burner body 261. As a result, the flange portion 267 of the hood 264 is pressed against the bottom portion 82 of the fixing jig 81 and comes into contact with the surface 91a of the flange portion 91 of the burner body 261. In this way, with the outer peripheral surface of the flange portion 267 of the hood 264 covered by the fixing jig 81, the flange portion 267 is sandwiched between the bottom portion 82 of the fixing jig 81 and the flange portion 91 of the burner body 261, and the hood 264 is fixed to the burner body 261.

[0056] As described above, the core synthesis burner 206 of the second modified example includes the fixing jig 81 that is detachably fixed to the burner body 261. The core synthesis burner 206 is configured such that the flange portion 267 of the hood 264 is sandwiched between the flange portion 91 of the burner body 261 and the bottom portion 82 of the fixing jig 81 with the outer peripheral surface of the flange portion 267 of the hood 264 covered by the fixing jig 81, thereby fixing the hood 264 to the burner body 261. In this way, by fixing the flange portion 91 of the hood 264 using a member other than a bolt, the hood 264 can be easily detached. In addition, because the fixing jig 81 is screwed onto the flange portion 91 of the burner body 261, the hood 264 can be easily detached from the burner body 261, and the core synthesis burner 206 can be easily disassembled for cleaning, etc.

[0057] Although the present disclosure has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present disclosure. 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]

[0058] 1: Glass particle deposit manufacturing equipment 2: Reaction vessel 3: Support rod 4: Dummy glass rod (starting rod) 5: Exhaust pipe 6,106,206,300: Core synthesis burner 7: Burner for clad synthesis 10: Lifting device 11: Raw material container 12: Gas supply device 20: Control unit 21:MFC (Mass Flow Controller) 61, 161, 261, 301: Burner body for core synthesis (example of burner body) 62,162: Burner base 62a, 162a: Tip part 62b,162b: Root part 62c, 162c: Stepped section 62d: End 63: Bracket 64,164,264,302: Food 64A: Cylindrical part 64B: Tapered section 64C: Opening 65, 66, 67, 91, 167, 267: Flange part 66a, 91a: Surface (fixed surface) 68, 69, 169: Bolt 70: Gasket 81: Fixture 82: Bottom 83: Hole 310: Tape M: Glass particle deposit (optical fiber base material)

Claims

1. 1. An apparatus for producing a soot glass deposit body, comprising: a burner for generating glass soot for producing a soot glass deposit body by supplying a glass raw material into a flame, The burner includes a metal burner body and a tubular hood for regulating the influence of airflow on the flame formed by the burner body; the hood is attached to the burner body so as to extend in a jetting direction in which the glass raw material jets from the burner body, the hood is formed from a material having a thermal expansion coefficient greater than that of quartz glass and less than or equal to that of a metal forming the burner body; the material forming the hood is one of silicon carbide and silicon nitride; The hood is detachable from the burner body, A flange portion protruding radially outward from the end of the hood is formed, The flange portion is detachably fixed to the burner body.

2. The hood is a cylindrical portion extending in the ejection direction; 2. The apparatus for manufacturing a soot glass deposit body according to claim 1, further comprising: a tapered portion located on the ejection direction side of said cylindrical portion, said tapered portion having an inner diameter increasing toward said ejection direction side.

3. 2. The apparatus for manufacturing a soot glass deposit body according to claim 1, wherein the flange portion is fixed to the burner body by a metal bolt.

4. Further provided is a fixing jig that is detachably fixed to the burner body, 2. The glass soot deposit body manufacturing apparatus of claim 1, wherein the hood is fixed to the burner body by clamping the flange portion between the burner body and the fixing jig with the outer surface of the flange portion covered by the fixing jig.

5. 5. The apparatus for manufacturing a soot glass deposit body according to claim 1, wherein the burner body and the hood are used in a burner for core synthesis in a VAD method.

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