Glass fine particle manufacturing device and fire-extinguishing part

Abstract

To provide a glass fine particle manufacturing device that can suppress damage to the device due to backfire, and to provide a fire-extinguishing part.SOLUTION: A glass fine particle manufacturing device includes: a vaporizer for vaporizing a raw material containing an organic silicon to generate a raw material gas; a burner part for burning a premixed gas in which the raw material gas and oxygen are mixed to generate glass fine particles; piping for connecting the vaporizer to the burner part; and a fire-extinguishing part for extinguishing fire propagating in a direction toward the vaporizer from the burner part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus for producing glass particles and a fire extinguishing section. [Background technology]

[0002] Patent Document 1 discloses a glass particle manufacturing apparatus including a vaporizer, a burner unit, and a pipe connecting them. In this apparatus, the vaporizer first vaporizes a raw material containing organic silicon to generate a raw material gas. Then, at an oxygen junction located in the vaporizer or the pipe, the raw material gas and oxygen are mixed to generate a premixed gas. Finally, the burner unit combusts the premixed gas to generate glass particles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-143107 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, organic silicon used in the manufacturing apparatus of Patent Document 1 has a boiling point higher than its flash point. Therefore, a premixed gas containing heated and vaporized organic silicon and oxygen can easily ignite and burn. Therefore, in the part of the piping where the premixed gas exists, a backfire phenomenon may occur in which a fire propagates in the opposite direction to the direction of gas flow. Such a fire propagating in the opposite direction (backfire) may damage the piping and equipment located between the burner and the vaporizer. In addition, even if the above-mentioned oxygen confluence point is downstream of the vaporizer, oxygen may flow back toward the vaporizer as the backfire propagates, and the backfire may reach the vaporizer.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a glass soot manufacturing apparatus and a fire extinguishing section that are capable of suppressing damage to the apparatus due to flashback. [Means for solving the problem]

[0006] In order to solve the above problems, the glass particle manufacturing apparatus according to aspect 1 of the present invention includes a vaporizer that vaporizes a raw material containing organic silicon to generate a raw material gas, a burner unit that burns a premixed gas containing the raw material gas and oxygen to generate glass particles, piping that connects the vaporizer and the burner unit, and a fire extinguishing unit that extinguishes a flame propagating from the burner unit toward the vaporizer.

[0007] According to the first aspect of the present invention, damage to the glass soot manufacturing apparatus caused by flashback can be suppressed.

[0008] In a second aspect of the present invention, in the glass soot manufacturing apparatus of the first aspect, the fire extinguishing section is provided in at least one of the vaporizer and the piping.

[0009] In addition, in a third aspect of the present invention, in the glass soot manufacturing apparatus of the second aspect, an oxygen junction where the raw material gas and the oxygen join to generate the premixed gas is located in the piping, and the fire extinguishing unit is provided in a portion of the piping between the vaporizer and the oxygen junction.

[0010] In addition, in a fourth aspect of the present invention, in the glass soot manufacturing apparatus of the second aspect, an oxygen junction where the raw material gas and the oxygen join to generate the premixed gas is located in the piping, and the fire extinguishing unit is provided in a portion of the piping between the burner unit and the oxygen junction.

[0011] A fifth aspect of the present invention is directed to the glass soot production apparatus according to any one of the first to fourth aspects, wherein a material constituting the fire extinguishing section has a melting point equal to or higher than a boiling point of the raw material gas.

[0012] In addition, a sixth aspect of the present invention is the glass soot production apparatus according to any one of the first to fifth aspects, wherein the extinguishing part includes an extinguishing part having a converted line width, a converted mesh hole width, and an average thickness, and the converted line width is q M [mm], and the equivalent mesh hole width is d M [mm] and the average thickness is T [mm], T≦5×q M In this case, the following equation (a) holds, and T>5×q M In this case, the following equation (b) holds. 0.85×q M -0.7 ×Td M ≧0 …(a) 0.85×q M -0.7 x5xq M -d M ≧0 …(b)

[0013] A seventh aspect of the present invention is directed to the glass soot production apparatus of the sixth aspect, wherein the equivalent mesh hole width is at least twice the equivalent diameter of the organosilicon.

[0014] In addition, an eighth aspect of the present invention is the glass soot production apparatus of the seventh aspect, wherein the equivalent mesh hole width is 10 times or more the equivalent diameter of the organosilicon.

[0015] In order to solve the above problems, a fire extinguishing unit according to a ninth aspect of the present invention is a fire extinguishing unit for extinguishing a flame propagating in a pipe, the fire extinguishing unit includes a fire extinguishing part having a converted line width, a converted mesh hole width, and an average thickness, and the converted line width is defined as q M [mm], and the equivalent mesh hole width is d M [mm] and the average thickness is T [mm], T≦5×q M In this case, the following equation (a) holds, and T>5×q M In this case, the following equation (b) holds. (a): 0.85 [mm] × q M -0.7 ×Td M ≧0 (b): 0.85 [mm] × q M -0.7 x5xqM -d M ≧0

[0016] According to the ninth aspect of the present invention, damage to the device caused by a flame (for example, a flashback) propagating through a pipe in which a fire extinguishing section is provided can be suppressed. Effect of the Invention

[0017] According to the above-described aspects of the present invention, it is possible to provide a glass soot manufacturing apparatus and a fire extinguishing section that are capable of suppressing damage to the apparatus due to flashback. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing a glass soot manufacturing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a modification of FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III shown in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line IV-IV shown in FIG. [Diagram 5] 1 is a graph showing the change in mesh hole width d capable of extinguishing flashback when the wire diameter r of the fire extinguishing component is changed. [Figure 6] FIG. 13 is a diagram showing the settings in Test Example 2. [Figure 7] 1 is a graph showing the change in mesh hole width d capable of extinguishing flashback when the average thickness of the fire extinguishing component is changed. [Figure 8] FIG. 2 shows a fire extinguishing component having a general shape. [Figure 9] FIG. 13 is a diagram for explaining a method for calculating the converted line width and the converted mesh hole width. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a glass soot manufacturing apparatus and a fire extinguishing unit according to an embodiment of the present invention will be described with reference to the drawings.

[0020] As shown in FIG. 1, the glass soot manufacturing apparatus 10 according to this embodiment includes a first introduction section 1, a second introduction section 2, a third introduction section 3, a vaporizer 4, a pipe 5, a burner section 6, and a fire extinguishing section 7.

[0021] The glass particle manufacturing apparatus 10 is an apparatus that generates glass particles G from a raw material containing organic silicon. The glass particle manufacturing apparatus 10 may be included in a glass base material manufacturing apparatus that manufactures a glass base material by depositing glass particles G (soot). The glass base material may be, for example, a porous glass base material. The glass base material may be a glass base material for optical fiber (optical fiber base material). However, the glass particle manufacturing apparatus 10 does not have to be an apparatus used in a glass base material manufacturing apparatus. Hereinafter, the glass particle manufacturing apparatus 10 may be simply referred to as "manufacturing apparatus 10".

[0022] An example of the organic silicon contained in the raw material of the glass particles G (hereinafter, sometimes referred to as "raw silicon") is alkylcyclosiloxane. In particular, octamethylcyclotetrasiloxane (OMCTS) can be suitably used as the raw silicon. OMCTS is also called "D4". Here, "D" represents a (CH3)2-Si-O- unit (hereinafter, sometimes referred to as "D unit"). "D4" means a structure in which four D units are connected in a ring shape. D4(C8H 24 O4Si4) is widely used industrially and is easily available, making it suitable for use as raw silicon. 18 O3Si3) and D5(C 10 H 30 However, as long as the glass particles G can be produced, the raw materials are not limited to these examples and can be changed as appropriate.

[0023] The first introduction part 1 supplies a raw material containing organic silicon to the vaporizer 4. The first introduction part 1 according to this embodiment includes a tank 1a, a flow rate control device 1b, and an introduction pipe 1p.

[0024] The inlet pipe 1p connects the tank 1a, the flow control device 1b, and the vaporizer 4 to one another. More specifically, the first introduction part 1 according to this embodiment has two inlet pipes 1p. One of the two inlet pipes 1p connects the tank 1a and the flow control device 1b. The other of the two inlet pipes 1p connects the flow control device 1b and the vaporizer 4.

[0025] The tank 1a stores a raw material containing organic silicon. The tank 1a supplies the raw material to the flow rate control device 1b through an inlet pipe 1p. When stored in the tank 1a, the raw material containing organic silicon is in a liquid state.

[0026] The flow rate control device 1b introduces the raw material supplied from the tank 1a through the introduction pipe 1p to the vaporizer 4. In addition, the flow rate control device 1b controls the flow rate of the raw material (organic silicon) introduced into the vaporizer 4, for example, by controlling the flow rate of the raw material discharged from the flow rate control device 1b to the introduction pipe 1p.

[0027] The second introduction section 2 supplies a carrier gas to the vaporizer 4. The carrier gas is a gas for carrying a raw material gas or a premixed gas, which will be described later, toward the burner section 6. The carrier gas may be an inert gas, such as argon. Alternatively, the carrier gas may be an active gas, such as oxygen. The carrier gas may be a mixed gas in which an inert gas and an active gas are mixed.

[0028] Although detailed illustration is omitted, the second introduction section 2 may include a carrier gas storage section (such as a tank or cylinder) for storing the carrier gas, and an introduction pipe connecting the carrier gas storage section to the vaporizer 4, etc.

[0029] The vaporizer 4 vaporizes a raw material containing organic silicon to generate a raw material gas. Specifically, the vaporizer 4 according to this embodiment vaporizes the raw material supplied from the first introduction part 1 to generate a raw material gas. The vaporizer 4 according to this embodiment discharges the generated raw material gas to a pipe 5.

[0030] Although detailed illustration is omitted, the vaporizer 4 may have, for example, an internal pipe through which the raw material and raw material gas flow, and a heating unit (heater, etc.) that heats the internal pipe. The heating unit heats the internal pipe, whereby the raw material flowing through the internal pipe is heated and vaporized.

[0031] The third introduction part 3 supplies oxygen to the pipe 5. Hereinafter, the oxygen supplied from the third introduction part 3 may be referred to as "raw oxygen". The raw oxygen is supplied to the pipe 5 and mixed with the raw gas. By mixing the raw oxygen with the raw gas, a flammable premixed gas is obtained.

[0032] The third introduction part 3 may include an oxygen storage part (such as a tank or a cylinder) (not shown) that stores raw oxygen, and an introduction pipe 3p that connects the oxygen storage part and the piping 5. In this embodiment, the introduction pipe 3p is connected to an intermediate part of the piping 5 (oxygen junction point P described later).

[0033] The piping 5 connects the vaporizer 4 and the burner unit 6. The piping 5 according to this embodiment has an oxygen junction point P. The oxygen junction point P is located in the middle of the piping 5. The oxygen junction point P is a point where the oxygen supplied from the third introduction part 3 merges with the raw material gas to generate a premixed gas.

[0034] Hereinafter, the portion of the piping 5 located upstream (on the vaporizer 4 side) of the oxygen junction P may be referred to as the upstream portion 5a. Similarly, the portion of the piping 5 located downstream (on the burner section 6 side) of the oxygen junction P may be referred to as the downstream portion 5b. Mainly the raw material gas and the carrier gas flow in the upstream portion 5a. Mainly the premixed gas and the carrier gas flow in the downstream portion 5b.

[0035] The pipe 5 may be heated by a heating unit (heater, etc.) not shown. This configuration can suppress liquefaction (re-liquefaction) of the raw material gas in the pipe 5. If the raw material gas is heated excessively, the raw material gas may polymerize. Therefore, it is preferable that the heating unit heats the pipe 5 (raw material gas) at a temperature at which the raw material gas does not polymerize.

[0036] The burner unit 6 burns the premixed gas to generate glass particles G. Specifically, the burner unit 6 according to this embodiment burns the premixed gas supplied from the pipe 5 with an oxyhydrogen flame to generate glass particles G (SiO2).

[0037] The extinguishing unit 7 extinguishes a flame (backfire) propagating from the burner unit 6 toward the vaporizer 4. The extinguishing unit 7 is disposed, for example, in the piping 5. The extinguishing unit 7 may be disposed in the upstream portion 5a of the piping 5 (see FIG. 1 ), or in the downstream portion 5b of the piping 5. The extinguishing unit 7 may be disposed in both the upstream portion 5a and the downstream portion 5b of the piping 5. Alternatively, the extinguishing unit 7 may be disposed in the vaporizer 4 (for example, the above-mentioned internal piping not shown). The extinguishing unit 7 may be provided in both the vaporizer 4 and the piping 5. That is, the extinguishing unit 7 may be provided in at least one of the vaporizer 4 and the piping 5.

[0038] As shown in Fig. 3, the fire extinguishing section 7 according to this embodiment has a mesh-like structure. The fire extinguishing section 7 is formed with a plurality of ventilation holes 70h through which air and flame can pass by penetrating the fire extinguishing section 7. When viewed from the direction in which the piping 5 extends (the direction in which the flame propagates), the area of ​​each ventilation hole 70h is smaller than the area of ​​the region surrounded by the inner circumferential surface 5c of the piping 5. In the following description, the direction in which the piping 5 extends (the direction in which the flame propagates) may be referred to as the propagation direction X.

[0039] Generally, there is a positive correlation between the propagation speed of a flame and temperature. Therefore, if the propagation speed of the flame is sufficiently slowed, the flame can be extinguished. In the extinguishing section 7 according to this embodiment, when the flame passes through the extinguishing section 7, the flame is divided by the multiple vent holes 70h. Since the propagation speed of the divided flame is slow, the flame can be extinguished by making the vent holes 70h sufficiently small. In addition, when the flame passes through the vent holes 70h, the state of the flame flow changes from turbulent flow to laminar flow. Since the laminar flow is slower than the turbulent flow, this effect also contributes to extinguishing the fire.

[0040] The material constituting the fire extinguishing section 7 preferably has a melting point higher than the boiling point of the organic silicon contained in the raw material. Examples of the material constituting the fire extinguishing section 7 include metal and ceramic. In particular, it is preferable to adopt a metal as the material constituting the fire extinguishing section 7. This is because metal has a higher thermal conductivity than ceramic and the like, and the temperature of the flame is reduced by the heat conduction from the flame to the fire extinguishing section 7, and this temperature reduction is thought to contribute to fire extinguishing.

[0041] A specific configuration of the fire extinguishing section according to this embodiment will be described below. As shown in Fig. 3 and Fig. 4, the fire extinguishing section according to this embodiment has a fire extinguishing component .

[0042] 3 and 4, each extinguishing component 70 is fixed to the inner circumferential surface 5c of the pipe 5. The extinguishing component 70 is fixed, for example, by being attached to the inner circumferential surface 5c of the pipe 5. However, as long as the extinguishing component 70 can be fixed to the pipe 5, the fixing method is not particularly limited and can be changed as appropriate.

[0043] 3, each extinguishing component 70 has a plurality of wires 71. The wires 71 may be made of a metal such as SUS. In the extinguishing component 70 according to the present embodiment, the plurality of wires 71 are arranged in a mesh pattern, so that ventilation holes 70h are formed between the wires 71. Each ventilation hole 70h penetrates the extinguishing component 70 in the propagation direction X.

[0044] Specifically, the multiple wires 71 include multiple vertical wires 71a and multiple horizontal wires 71b. The vertical wires 71a extend in a direction intersecting (for example, perpendicular to) the propagation direction X. The horizontal wires 71b extend in a direction intersecting (for example, perpendicular to) both the propagation direction X and the direction in which the vertical wires 71a extend. A space surrounded by two adjacent vertical wires 71a and two adjacent horizontal wires 71b serves as an air hole 70h.

[0045] The space surrounded by the inner circumferential surface 5c of the pipe 5 and at least one of the wires 71a and 71b also corresponds to the vent hole 70h through which air and flame can pass. Hereinafter, such a vent hole 70h facing the inner circumferential surface 5c may be referred to as an outer hole 70h2. The outer hole 70h2 is also the vent hole 70h located at the outermost periphery among the multiple vent holes 70h. In addition, among the multiple vent holes 70h, the vent holes 70h other than the outer hole 70h2 may be referred to as an inner hole 70h1. That is, the inner hole 70h1 is the vent hole 70h surrounded by two adjacent vertical wires 71a and two adjacent horizontal wires 71b.

[0046] In the extinguishing section 7 (extinguishing component 70) according to this embodiment, the wires 71 are arranged so that the inner holes 70h1 form a mesh pattern M when viewed from the propagation direction X. The term "mesh pattern M" in this specification means that each inner hole 70h1 has a substantially square shape, and the inner holes 70h1 are arranged at substantially equal intervals in a two-dimensional lattice shape. The term "substantially square shape" in this specification also includes cases where the shape can be considered to be a square shape if manufacturing errors are removed. Similarly, the term "substantially equal intervals" in this specification also includes cases where the shape can be considered to be equal intervals if manufacturing errors are removed.

[0047] The extinguishing component 70 according to the present embodiment has a mesh hole width d [mm], a line width q [mm], and an average thickness T [mm] as parameters related to the extinguishing performance of the extinguishing component 70 (fire extinguishing section 7). The mesh hole width d is the length of one side of the inner hole 70h1 having a substantially square shape when viewed from the propagation direction X (see FIG. 3). The line width q is the width of the portion other than the ventilation hole 70h when the extinguishing component 70 is viewed from the propagation direction X (see FIG. 3). In the present embodiment, the line width q is equal to the diameter of the wire 71 (hereinafter referred to as the wire diameter r). The average thickness T is the average value of the thickness (dimension in the propagation direction X) of the extinguishing component 70 (see FIG. 4). In the present embodiment, the average thickness T can be considered to be equal to the wire diameter r.

[0048] The conditions that the parameters d, q, and T should preferably satisfy will be described below using specific test examples.

[0049] (Test Example 1) The manufacturing apparatus 10 shown in FIG. 1 was used. OMCTS was used as the raw silicon. Oxygen was used as the carrier gas. In the mixed gas, the mixture ratio R (molar ratio n1 / n2) of the amount of substance (n1) of the D unit contained in OMCTS to the amount of substance (n2) of oxygen was adjusted to 0.79.

[0050] Under these conditions, flashback was caused by gradually reducing the flow rate of the premixed gas supplied to the burner section 6. When the flow rate (flow velocity) of the premixed gas is equal to or greater than the flame propagation speed, the flame attempting to propagate upstream is pushed back by the premixed gas, and no flashback occurs. When the flow rate (flow velocity) of the premixed gas is less than the flame propagation speed, the premixed gas is unable to push the flame back downstream. This causes the flame to propagate upstream, resulting in a flashback phenomenon. Note that the maximum flashback propagation speed in this test example was 5 m / s.

[0051] As the extinguishing section 7, only one extinguishing part 70 shown in FIG. 3 was placed in the upstream part 5a of the pipe 5. The material forming the extinguishing part 70 (wire 71) was SUS. Six types of extinguishing parts 70 with different wire diameters r were prepared. The wire diameters r of the prepared extinguishing parts 70 were 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm, respectively. Then, for each of the six types of extinguishing parts 70 (extinguishing section 7), the mesh hole width d at which flashback was extinguished was confirmed.

[0052] When a flashback occurs, the premixed gas present upstream of the extinguishing section 7 burns, and soot (glass particles G) adheres to the portion of the inner circumferential surface 5c of the pipe 5 upstream of the extinguishing section 7. In this test example, whether or not the fire was extinguished by the extinguishing section 7 was determined by checking whether such soot adhesion occurred before and after the extinguishing section 7 (upstream and downstream).

[0053] Figure 5 is a graph summarizing the results of confirming the mesh hole width d at which flashback is extinguished in this test example. Each of the plotted points in Figure 5 indicates the maximum mesh hole width d at which flashback can be extinguished for the corresponding wire diameter r. Curve C is an approximation curve of the plotted points. Curve C is expressed by the following formula (1). d=0.85×r 0.3 …(1)

[0054] Here, the region A1 above the curve C corresponds to the case where the fire extinguishing unit 7 (fire extinguishing component 70) is unable to extinguish the flashback and the flashback passes through the fire extinguishing unit 7. The region B1 below the curve C corresponds to the case where the fire extinguishing unit 7 (fire extinguishing component 70) is able to extinguish the flashback. The region B1 below the curve C is expressed by the following formula (2). Formula (2) corresponds to the condition where the fire extinguishing unit 7 can extinguish the flashback when the fire extinguishing unit 7 includes only one fire extinguishing component 70 of FIG. 3 (when the line width q and average thickness T are both equal to the wire diameter r). 0.85×r 0.3 -d≧0 …(2)

[0055] That is, in this test example, it was found that the smaller the mesh hole width d and the thicker the wire diameter r, the easier it is to extinguish flashbacks. Also, as shown in Fig. 5, the larger the wire diameter r, the less improvement in fire extinguishing performance is achieved by increasing the wire diameter r. This is thought to be because the larger the wire diameter r, the smaller the total cross-sectional area of ​​the entire fire extinguishing component 70 through which the flame can pass becomes, and the faster the flashback attempts to pass through the fire extinguishing section 7.

[0056] In this test example, the line width q and average thickness T of the fire extinguishing component 70 are both equal to the wire diameter r. For this reason, in this test example, it is difficult to separate the effect of the line width q on the fire extinguishing performance of the fire extinguishing part 7 from the effect of the average thickness T on the fire extinguishing performance of the fire extinguishing part 7. Therefore, an experiment shown in the following test example 2 was conducted.

[0057] (Test Example 2) A plurality of extinguishing components 70 of FIG. 3 with a wire diameter r of 0.2 mm were prepared. As shown in FIG. 6, the plurality of extinguishing components 70 were arranged overlapping each other without any gaps in the propagation direction X. The number of extinguishing components 70 included in the extinguishing unit 7 was changed between 1 and 10, and the mesh hole width d at which the backfire was extinguished was confirmed for each case. Changing the number of extinguishing components 70 can be regarded as increasing the average thickness T while keeping the wire width q constant (wire diameter r) in the extinguishing component 70 shown in FIG. 3. The conditions other than the wire diameter r and the number (average thickness T) of the extinguishing components 70 were regarded as being the same as those in the above-mentioned test example 1.

[0058] Fig. 7 is a graph summarizing the results of confirming the mesh hole width d at which flashbacks are extinguished in this test example. Each of the plotted points in Fig. 7 indicates the maximum mesh hole width d at which flashbacks could be extinguished for the average thickness T of the corresponding extinguishing component 70. The area A2 above the plotted points corresponds to the case where the fire extinguishing section 7 (fire extinguishing component 70) was unable to extinguish the flashbacks and the flashbacks passed through the fire extinguishing section 7. The area B2 below the plotted points corresponds to the case where the fire extinguishing section 7 (fire extinguishing component 70) was able to extinguish the flashbacks.

[0059] As shown in Fig. 6, in a region where the average thickness T is 5 times the wire diameter r or less, the maximum mesh hole width d capable of extinguishing flashback was approximately proportional to the average thickness T. On the other hand, in a region where the average thickness T is more than 5 times the wire diameter r, the mesh hole width d capable of extinguishing flashback did not change substantially even when the average thickness T was increased. It was also confirmed that in the case of fire extinguishing components 70 having other wire diameters r, when the average thickness T was more than 5 times the wire diameter r, the mesh hole width d capable of extinguishing flashback did not change substantially.

[0060] The reason why this phenomenon occurs is considered as follows. First, as the average thickness T increases, the vent hole 70h formed in the extinguishing component 70 becomes longer (the dimension in the propagation direction X becomes larger). In a region where the length of the vent hole 70h is equal to or less than a certain value, the longer the vent hole 70h, the more laminar the flashback passing through the vent hole 70h becomes, and the slower the propagation speed of the flashback becomes. Therefore, the longer the vent hole 70h, the better the fire extinguishing performance of the extinguishing component 70. On the other hand, when the vent hole 70h reaches a certain length, the flashback passing through the vent hole 70h becomes sufficiently laminar, and even if the vent hole 70h is further lengthened, the propagation speed of the flame does not change. Therefore, it is considered that even if the vent hole 70h is lengthened (i.e., even if the fire extinguishing component 70 is made larger than a certain value), the fire extinguishing performance of the fire extinguishing component 70 does not change. It is believed that this test example experimentally clarified that the average thickness T at which flashback is sufficiently laminarized and fire extinguishing performance reaches its maximum value is five times the wire diameter r.

[0061] Considering the results of Test Example 2, the above-mentioned formula (2), and the fact that the wire diameter r is equal to the wire width q in the fire extinguishing component 70 in Fig. 3, the conditions under which the fire extinguishing unit 7 can extinguish a flashback are as follows: That is, the conditions under which the fire extinguishing unit 7 including the fire extinguishing component 70 can extinguish a flashback are that the following formula (3) holds when T <= 5 x q, and that the following formula (4) holds when T > 5 x q. 0.85×q -0.7 ×Td≧0 …(3) 0.85×q -0.7 ×5×qd≧0 …(4)

[0062] As shown in formulas (3) and (4), the larger the line width q, the smaller the mesh hole width d capable of extinguishing a flashback. The reason for this is considered as follows. That is, the larger the line width q, the smaller the total cross-sectional area of ​​the entire fire extinguishing component 70 through which the flame can pass, and the speed at which the flashback attempts to pass through the fire extinguishing section 7 increases. Therefore, in order to extinguish a flashback, it is considered necessary to slow down the propagation speed of the flashback by thickening the fire extinguishing component 70 or reducing the mesh hole width d.

[0063] In the extinguishing component 70 described above, the wires 71 are arranged in a mesh pattern, and the inner hole 70h1 forms a mesh pattern M when viewed from the propagation direction X. However, the configuration of the extinguishing component 70 can be appropriately changed as long as a plurality of vent holes 70h (inner holes 70h1) are formed through the extinguishing section 7 to allow air and flames to pass in the propagation direction X. For example, the vent holes 70h (inner holes 70h1) do not need to form the mesh pattern M. For example, the extinguishing component 70 may have a crimped ribbon shape, a perforated plate shape, a porous shape, or the like.

[0064] Hereinafter, conditions equivalent to the above-mentioned formula (3) and formula (4) will be considered for the extinguishing component 70 in which the ventilation hole 70h (inner hole 70h1) does not constitute the mesh pattern M. In the following description, the extinguishing component 70 in which the ventilation hole 70h (inner hole 70h1) does not constitute the mesh pattern M may be referred to as a "fire extinguishing component 70' having a normal shape" or simply as a "fire extinguishing component 70'". The number of the outer holes 70h2 is sufficiently smaller than the number of the inner holes 70h1. Therefore, it is considered that the influence of the shape of the outer holes 70h2, etc. on the fire extinguishing performance of the extinguishing component 70' can be ignored. In the following discussion, the shape of the outer holes 70h2, etc. are also ignored.

[0065] In this embodiment, the converted line width q M and equivalent mesh hole width d M and the average thickness T are introduced. The average thickness T is defined in the same way as in the case of the fire extinguishing component 70 described above. The converted line width q M is a parameter equivalent to the line width q, which is a parameter of the fire extinguishing component 70. M is a parameter equivalent to the mesh hole width d, which is a parameter of the fire extinguishing component 70. When a plurality of ventilation holes 70h (inner holes 70h1) constitute the mesh pattern M, the converted line width q M corresponds to the line width q, and the equivalent mesh hole width d M corresponds to the mesh hole width d.

[0066] Specifically, it is considered that the multiple ventilation holes 70h (the inner holes 70h1) of the fire extinguishing component 70′ are deformed into the mesh pattern M while maintaining the total cross-sectional area (the sum of the cross-sectional areas) in a cross section perpendicular to the propagation direction X. M , d M corresponds to the parameters q and d in the transformed mesh pattern M. Hereinafter, the conversion parameters q M , d M will be explained in detail.

[0067] First, as shown in FIG. 8, a cubic region with a side length of D is extracted from the fire extinguishing component 70'. In this case, the cubic region does not include the outer hole 70h2, but includes only the inner hole 70h1. The value of the length D is arbitrary. For example, the cubic region may be extracted so that the value of the length D is equal to the average thickness T of the fire extinguishing component 70'.

[0068] Here, if the open porosity of the fire extinguishing part 70' is p, the total volume V of the ventilation holes 70h included in the cubic region is void is expressed by the following equation (5).

[0069]

number

[0070] The average volume of one vent hole 70h is v void Then, the average number of pores contained in the cubic region (average number of pores) is N c is expressed by the following equation (6).

[0071]

number

[0072] Here, the multiple air holes 70h (inner holes 70h1) included in the cubic region are transformed into a mesh pattern M as shown in Fig. 9. That is, the shape and arrangement of the air holes 70h (inner holes 70h1) are changed so as to satisfy the following conditions (A) to (E). (A) The number of inner holes 70h1 is the average number of pores N c Matches. (B) The volume of each inner hole 70h1 is the average volume v void Matches. (C) Each inner hole 70h1 has a square shape when viewed in the propagation direction X. (D) Each inner hole 70h1 penetrates the cubic region in the propagation direction X. (E) The multiple inner holes 70h1 included in the cubic shape are arranged at equal intervals in a two-dimensional lattice pattern when viewed from the propagation direction X.

[0073] According to the conditions (A), (C), and (E), the cubic region has a surface facing the propagation direction X, and the plurality of inner holes 70h1 are N c 1 / 2 ×N c 1 / 2 Therefore, the following formula (7) is established. Furthermore, the following formula (8) can be derived from formula (7).

[0074]

number

[0075] From the conditions (B), (C), and (D), the following formula (9) is established. From the formula (9), the following formula (10) is derived. By combining the formulas (8) and (10), the reduced line width q M and equivalent mesh hole width d M That is, the open porosity p and the average volume v of the fire extinguishing component 70' can be calculated. void Based on this, the conversion parameter q M , d M can be calculated (see also equations (5) and (6)).

[0076]

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[0077] Average volume v voidcan be calculated based on the following formulas (11) to (13) according to the shape of the ventilation hole 70h (inner hole 70h1). Formula (11) corresponds to the case where the inner hole 70h1 has a rectangular prism shape (for example, when the fire extinguishing component 70' has a mesh-like structure). Formula (12) corresponds to the case where the inner hole 70h1 has a cylindrical shape (for example, when the fire extinguishing component 70' is a porous plate). Formula (13) corresponds to the case where the inner hole 70h1 can be approximated by a spherical shape (for example, when the fire extinguishing component 70' is a porous body). In formulas (11) to (13), d e is the average value of the diameters of the air holes 70h (the inner holes 70h1) (average pore diameter).

[0078]

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[0079] In the above formula (13), it is assumed that the cubic region is extracted so that the length D of one side of the cubic region is equal to the average thickness T of the fire extinguishing component 70'. Even if the shape of the inner hole 70h1 does not fit the above example, if the shape of the inner hole 70h1 is known, the average volume v can be calculated based on the known shape. void It is possible to calculate

[0080] The conversion parameter q calculated above M , d M By applying the above formulas (3) and (4), the condition under which the fire extinguishing unit 7 can extinguish a flashback when the fire extinguishing unit 7 includes the fire extinguishing component 70′ is obtained. That is, T≦5×q M In this case, the following equation (a) holds, and T>5×q M In this case, the condition for extinguishing flashback by fire extinguishing unit 7 including fire extinguishing component 70' is that the following formula (b) is satisfied. 0.85×q M -0.7 ×Td M ≧0 …(a) 0.85×q M -0.7 x5xq M -d M ≧0 …(b)

[0081] In addition, the equivalent mesh hole width d M is preferably at least twice the equivalent diameter of the organic silicon (raw silicon) contained in the raw material, and more preferably at least 10 times the equivalent diameter. M This is because when the equivalent diameter of the organic silicon approaches that of the organic silicon, the organic silicon is likely to clog the fire extinguishing component 70. Note that the equivalent diameter of alkylcyclosiloxane, which is an example of organic silicon, is about 1 nm.

[0082] Next, the operation of the manufacturing apparatus 10 and the fire extinguishing component 70 configured as above will be described.

[0083] Conventionally, for example, a glass particle manufacturing apparatus disclosed in Patent Document 1 is known. Here, the organosilicon used in the manufacturing apparatus has a boiling point higher than its flash point. For example, in the case of OMCTS, the boiling point is 175°C and the flash point is 51°C. Therefore, in the part of the pipe where the premixed gas exists, a flashback phenomenon may occur. The flashback may damage various equipment (pipes, vaporizer, etc.) equipped in the manufacturing apparatus.

[0084] To address this issue, the manufacturing apparatus 10 according to this embodiment is provided with a fire extinguishing component 70 capable of extinguishing flashback. This reduces the possibility that various pieces of equipment (such as the vaporizer 4 and the piping 5) provided in the manufacturing apparatus 10 will be damaged by flashback. In particular, even if the piping 5 is heated by a heating unit (not shown) or the like and is prone to flashback, the fire extinguishing component 70 can suppress damage to the manufacturing apparatus 10 caused by flashback.

[0085] As described above, the glass soot manufacturing apparatus 10 according to this embodiment includes the vaporizer 4 that vaporizes a raw material containing organic silicon to generate a raw material gas, the burner unit 6 that burns a premixed gas in which the raw material gas and oxygen are mixed to generate glass soot G, the pipe 5 that connects the vaporizer 4 and the burner unit 6, and the extinguishing unit 7 that extinguishes a flame propagating from the burner unit 6 toward the vaporizer 4. This configuration can suppress damage to the glass soot manufacturing apparatus 10 due to backfire.

[0086] Moreover, the fire extinguishing section 7 may be provided in at least one of the vaporizer 4 and the pipe 5. According to this configuration, damage to the vaporizer 4 due to flashback can be reliably suppressed.

[0087] Further, an oxygen junction P where the raw material gas and oxygen (raw material oxygen) join to generate a premixed gas may be located in the pipe 5, and the fire extinguishing unit 7 may be provided in a portion of the pipe 5 between the vaporizer 4 and the oxygen junction P (i.e., the upstream portion 5a). According to this configuration, the fire extinguishing unit 7 can be introduced into the glass soot manufacturing apparatus 10 without changing the configuration of the downstream portion 5b from that of the conventional apparatus.

[0088] Furthermore, the fire extinguishing unit 7 may be provided in a portion of the pipe 5 between the burner unit 6 and the oxygen junction P (i.e., the downstream portion 5b). With this configuration, the area that is damaged by flashback can be made smaller than when the fire extinguishing unit 7 is provided in the upstream portion 5a, for example.

[0089] Furthermore, the material constituting the fire extinguishing section 7 may have a melting point equal to or higher than the boiling point of the raw material gas. This configuration can suppress damage (melting) of the fire extinguishing section 7 due to backfire, and suppress deterioration of the fire extinguishing performance of the fire extinguishing section 7.

[0090] In addition, the extinguishing section 7 has a converted line width q M , equivalent mesh hole width d M , and a fire extinguishing component 70 having an average thickness T, T≦5×q M In the case of T>5×q, the above formula (a) is valid. M In this case, the above formula (b) may be established. According to this configuration, damage to the manufacturing apparatus 10 due to flashback can be more reliably suppressed.

[0091] In addition, the equivalent mesh hole width d M may be at least twice the equivalent diameter of the organosilicon. This configuration can prevent the fire extinguishing component 70 from clogging.

[0092] In addition, the equivalent mesh hole width d M may be 10 times or more the equivalent diameter of the organosilicon. With this configuration, clogging of the fire extinguishing component 70 can be further suppressed.

[0093] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0094] 3 may have, in addition to the wires 71, an annular frame portion fixed to the inner circumferential surface 5c of the pipe 5. Each wire 71 may be fixed to the frame portion. In this case, the space surrounded by the frame portion and at least one wire 71 corresponds to the outer hole 70h2 described above.

[0095] Furthermore, when the carrier gas contains oxygen, the production apparatus 10 does not need to include the third introduction part 3 for introducing oxygen into the pipe 5. In this case, the oxygen junction P where the raw material gas and oxygen (raw material oxygen) join to generate a premixed gas is located in the vaporizer 4.

[0096] Moreover, the fire extinguishing section 7 may have a plurality of fire extinguishing components 70 (70') arranged in the propagation direction X at intervals.

[0097] Furthermore, the fire extinguishing unit 7 may be provided in a pipe of an apparatus other than the pipe 5 of the glass soot manufacturing apparatus 10. In this case, the fire extinguishing unit 7 can suppress damage to the apparatus caused by a flame (e.g., a backfire) propagating through the pipe in which the fire extinguishing unit 7 is provided. Even when the fire extinguishing unit 7 is provided in the apparatus, the fire extinguishing unit 7 has at least one fire extinguishing component 70, and the parameter q is set so that the conditions of the above-mentioned formulas (a) and (b) are satisfied. M , d M , T, and N may be set. This makes it possible to more reliably suppress damage to the device due to flashback.

[0098] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate. [Explanation of symbols]

[0099] 10... Manufacturing device 4... Vaporizer 5... Piping 6... Burner section 7... Fire extinguishing section 70, 70'... Fire extinguishing parts q M …Converted line width d M …Equivalent mesh hole width T…Average thickness

Claims

1. a vaporizer for vaporizing a raw material containing organic silicon to generate a raw material gas; a burner unit that burns a premixed gas obtained by mixing the raw material gas and oxygen to generate glass particles; A pipe connecting the vaporizer and the burner unit; and a fire extinguishing unit that extinguishes a flame propagating from the burner unit toward the vaporizer. Glass particle manufacturing equipment.

2. The fire extinguishing unit is provided in at least one of the vaporizer and the piping.

2. The glass soot manufacturing apparatus according to claim 1.

3. an oxygen junction where the raw material gas and the oxygen are joined to generate the premixed gas is located in the pipe; The fire extinguishing unit is provided in a portion of the piping between the vaporizer and the oxygen junction point.

3. The glass soot manufacturing apparatus according to claim 2.

4. an oxygen junction where the raw material gas and the oxygen are joined to generate the premixed gas is located in the pipe; The fire extinguishing unit is provided in a portion of the piping between the burner unit and the oxygen confluence point.

3. The glass soot manufacturing apparatus according to claim 2.

5. The material constituting the fire extinguishing section has a melting point equal to or higher than the boiling point of the raw material gas. The glass soot manufacturing apparatus according to claim 1 .

6. The extinguishing section includes a fire extinguishing component having a converted line width, a converted mesh hole width, and an average thickness; The converted line width is q Ｍ [mm], and the equivalent mesh hole width is d Ｍ [mm] and the average thickness is T [mm], T≦5×q Ｍ In the case of T>5×q, the following formula (a) is satisfied: Ｍ In this case, the following formula (b) is satisfied: The glass soot manufacturing apparatus according to claim 1 . 0.85×q Ｍ －０．７ ×T-d Ｍ ≧0 …(a) 0.85×q Ｍ －０．７ ×5×q Ｍ -d Ｍ ≧0 …(b)

7. The equivalent mesh pore width is at least twice the equivalent diameter of the organic silicon.

7. The glass soot manufacturing apparatus according to claim 6.

8. The reduced mesh pore width is 10 times or more the equivalent diameter of the organosilicon; The glass soot manufacturing apparatus according to claim 7.

9. A fire extinguishing unit for extinguishing a flame propagating in a pipe, The extinguishing section includes a fire extinguishing component having a converted line width, a converted mesh hole width, and an average thickness; The converted line width is q Ｍ [mm], and the equivalent mesh hole width is d Ｍ [mm] and the average thickness is T [mm], T≦5×q Ｍ In the case of T>5×q, the following formula (a) is satisfied: Ｍ In this case, the following formula (b) is satisfied: Fire department. (a):0.85[mm]×q Ｍ －０．７ ×T-d Ｍ ≧0 (b):0.85[mm]×q Ｍ －０．７ ×5×q Ｍ -d Ｍ ≧0

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