KR20040040056A - Burner for making fine particles for deposition of silica particles - Google Patents

Abstract

PURPOSE: A burner for producing fine particles for deposition of silica particles is provided to produce a preform having improved doping quality and less soot loss by the specific design of the burner. By using the burner, it is possible to provide a large quantity of uniform soot particles and uniform doping concentration over the whole flame range, and prevent condensation which is caused by increase in flow rate and wart-like defect on the surface of a preform which is caused by a turbulent flow. CONSTITUTION: The burner comprises: a cylindrical body(11); a central chamber(30) which is formed in the center of the body and has a spiral channel(34) to supply a glass making raw material and a mixed gas with oxygen to the upper part of the body; a first oxygen gas supply passage(40) which surrounds the central chamber at a certain distance and supplies the oxygen gas to the upper part of the body; a second oxygen gas supply passage(50) which surrounds the first gas supply passage at a certain distance and supplies the oxygen gas to the upper part of the body; and a hydrogen gas supply passage(60) which surrounds the second oxygen gas supply passage and supplies the hydrogen gas to the upper part of the body. Nozzles(32,42,52,62) for the chamber, the first and the second oxygen gas supply passages, and the hydrogen gas supply passage, respectively are provided on the top of the body in the form of concentric circles.

Description

BURNER FOR MAKING FINE PARTICLES FOR DEPOSITION OF SILICA PARTICLES}

The present invention relates to a burner, and more particularly to a burner for preparing fine powder for the deposition of silica particles used in the preparation of preforms of optical fibers.

In general, flame hydrolysis has been widely used as a method of forming glass particles, and in particular, it has been used as a method of manufacturing an optical fiber base material by applying the optical fiber.

Methods for manufacturing optical fibers or acoustic waveguide fibers include Modified Chemical Vapor Deposition (MCVD), Vapor Axial Deposition (VAD), Outside Vapor Deposition; OVD) or other hybrid process. The most commonly used materials are SiCl ₄ or halogen-containing raw materials including Si, and dopants for controlling the refractive index of the core are POCl ₃ and BCl _3. GeCl ₄ and the like have been used. In addition, as a gas used as a heat source for causing oxidation and hydrolysis reactions, hydrogen (H ₂ ), methane, propane, butane, or a mixed gas of two or more kinds was used, and a flammable gas for maintaining the temperature of the flame. Combustion supporting gas (O ₂ ) has been used.

In the OVD process, halogenated raw materials such as SiCl ₄ form silica soot particles at about 1100 ° C. in an evaporated state by oxidation and hydrolysis reactions as shown in the following equation.

SiCl ₄ + 2O ₂ ---> SiO ₂ + 2Cl ₂ (oxidation reaction)

SiCl ₄ + 2H ₂ O ---> SiO ₂ + 4HCl (hydrolysis)

The particles thus formed are gradually grown into spherical particles while colliding and agglomerating along the air stream of the flame and attached to the outer circumferential surface of the target rod or mandrel to increase their diameter, and in the VAD method, axial growth occurs to increase porosity. Porous) forms a base material.

The porous base material is manufactured as a transparent optical fiber preform through sintering in an atmosphere of helium and chlorine gas in a furnace maintaining a temperature of 1400 ~ 1600 ℃.

The details of particle adhesion in OVD and VAD processes are as follows. In general, the particle attachment process is achieved by the impact of particles of high temperature and fine SiO ₂ sprayed from a circular flame generator on a relatively low woolen rod. Known. At this time, due to the combustion of hydrogen and oxygen emitted from the burner, oxidation reaction of SiCl ₄ and hydrolysis by flame occurs near the burner surface to form SiO ₂ particles having a size of 0.1 μm. These particles collide, fuse, and aggregate. The particles grow to about 0.2 ~ 0.3μm and move with the hot gas emitted from the burner. These particles also pass around the rod and become attached to the relatively low wool due to temperature gradient effects. Particle adhesion by thermophoresis is determined by the flow and temperature field of the flame, and the flow and temperature field also depend on the temperature of the cylinder.

Unlike the MCVD method, the OVD method and the VAD method are a process of attaching SiO ₂ particles generated to the outer circumferential surface of the target rod without growing the glass particles in the tube. Likewise, it is determined by the flame flow and temperature field by the burner. Therefore, the design technology of the burner, which is the source of generating the chute, is a core technology. Particularly, when the core is deposited, the particle stream line determines the refractive index distribution, so the internal structure of the burner and the design of the nozzle are very important. .

To date, a number of burner designs have been devised and known, and a brief description of typical burner designs is US 4,165,223, US 3,642,521, US 3,565,345, US 3,698,936, US 4,810,189, US 5,599,371, and US4,474,593 are concentric. The technique using a tube is disclosed.

However, in the conventionally disclosed technique, as pointed out in US Pat. No. 4,801,322, the conventional burner has a problem in that the formed glass particles adhere to the surface of the burner and the particles grow to block the nozzle of the burner. In order to solve this problem, a method of blocking by an inert gas may be used, but in this case, as pointed out in US Pat. No. 4,474,593, a problem of temperature drop in the flame occurs seriously, which is inevitably a cause of disturbing the deposition condition during deposition. .

As a method for solving the above problems, US 4,165,223 can simultaneously use oxygen (O ₂ ) as an oxidation reaction and a heat source using oxygen (O ₂ ) as a blocking gas that can simultaneously solve the burner surface adhesion and temperature drop problem of glass particles. It was made.

In addition to the recent prior art, US 6,363,746 discloses "Method and Apparatus for making Multi-Component Glass soot". The present invention uses a method of installing a cylindrical structure in which a plurality of holes are designed inside the center nozzle, and jetting liquid glass raw material by jetting oxygen gas, which is a carrier gas. However, in the method of supplying liquid raw materials, the generation of preform loose skin due to drop formation is inevitable depending on the flow rate, and the liquid injection is performed when the flow rate of carrier gas is increased to increase the deposition efficiency. Drop formation due to (Liquid jetting) occurs more severely, making it impossible to use as an optical fiber preform. In addition, when the pressure difference between the liquid raw material gas and the carrier gas is different, there is a concern that the carrier gas line may be contaminated. Therefore, the liquid transportation method is not preferable as a method for increasing the deposition efficiency. In addition, the inclined design of the gas nozzle in the burner to the center has the effect that the flame is collected, and thus the positive effect can be obtained at the initial deposition. However, when the flames are collected, the distance between the flames and the rods changes as the deposition proceeds, and the collected flames cannot be spread again beyond the focal length, which is not preferable.

According to the recent trend of increasing the size of the preform, as the size of the preform increases, the distance from the burner is inevitably closer, so that the nozzle is inclined to be designed in a preferable direction.

As another type of burner, US 5,599,371 discloses "Method of Using Precision Burners for Oxidizing Halide-Free Silicon-Containing Compounds". In this patent, nitrogen is used as the first shield gas, which, as pointed out earlier, causes the core flame temperature to drop significantly, making it difficult to form particles at very high levels in the burner. As a result, in the above-described technique, the particle size is small, so that dehydration is difficult, and this has been one cause of incomplete sintering during sintering. In addition, the above-described invention has a disadvantage in that the structure inside the burner is very complicated, so that the design is difficult and the manufacturing and maintenance costs are high.

The present invention was devised to solve the above problems, and by producing a silica particle through a unique structural design inside the burner, the silica particles can be produced in a preform of excellent quality with little loss of doping quality and a large number of soot It is an object to provide a burner for preparing fine powder for vapor deposition.

More specifically, in the burner described above, the mixing of source gas and oxygen is made as smooth as possible so that a uniform amount of soot particles are formed, and when a dopant is used, a uniform doping concentration can be obtained in the entire flame section. Even if this increases, the condensation caused by the temperature decrease inside the burner does not occur. In addition, in the burner described above, the type of the blocking gas is selected to prevent the flame temperature caused by the inert gas, the preform surface irregularities (Wart like defect or Lizard skin) due to the turbulence are formed, and the burner structure is simplified. At the same time, the internal structure is designed to prevent the flame from shifting in a specific direction so that the gas is sprayed simply and uniformly so that the glass particles are uniformly formed, grow, and adhere to the preform. Do not make the focus in the vertical direction.

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a perspective view showing the appearance of a burner according to the present invention;

2 is a cross-sectional view showing the internal structure of the burner according to the present invention.

3 is a plan view showing a gas nozzle arranged on the upper surface of the burner shown in FIG.

FIG. 4 is a diagram showing a modification of the burner shown in FIG. 2. FIG.

<Explanation of symbols for the main parts of the drawings>

10. Burner 12. Burner top cover 20. Glass raw material gas inlet pipe

22. Oxygen gas inlet pipe 24. Doping material inlet pipe 30. Central chamber

32. Central nozzle 34. Spiral flow path 36. Central chamber heating device

40. First oxygen gas inlet pipe 42. First oxygen gas nozzle 44. First oxygen gas filter

46,56,66..pinhole 50..second oxygen gas inlet pipe 52..second oxygen gas nozzle

54. Second filter for oxygen gas 60. Hydrogen gas inlet pipe 62. Hydrogen gas nozzle

64. Hydrogen gas filter

In order to achieve the above object, a burner for preparing fine powder for silica particle deposition according to the present invention has a cylindrical body, a central chamber which is formed at the center of the body and supplies a mixed gas of glass raw material and oxygen to the upper part of the body, It is installed to surround the central chamber at a predetermined interval, the first oxygen gas supply path for supplying the oxygen gas to the upper portion of the body, the oxygen gas is installed to surround the first oxygen gas supply path at a predetermined interval the upper portion of the body And a second oxygen gas supply path for supplying the gas, and a hydrogen gas supply path for supplying the hydrogen gas to the upper portion of the body by being installed to surround the second oxygen gas supply path at a predetermined interval.

Preferably, a spiral flow passage is formed in the central chamber for improving the mixing of the mixed gas.

In addition, the central chamber may be provided with a central chamber heating device for preventing the liquefaction of the mixed gas.

In addition, the central chamber heating apparatus is preferably a heating coil installed around the central chamber.

Preferably, the central chamber supplies a mixture of the doping material together with the glass raw material gas and the oxygen gas.

At this time, the amount of oxygen supplied from the first oxygen gas supply path is preferably mixed with the mixed gas supplied from the central chamber but maintained so that the soot does not adhere to the upper surface of the body.

In addition, the amount of oxygen supplied from the second oxygen gas supply path is preferably controlled to maintain a constant temperature of the flame generated on the body.

In the burner described above, it is also preferable that the first and second oxygen gas supply paths and the hydrogen gas supply paths each consist of independent chambers.

Preferably, a plurality of fine nozzles are formed at upper ends of the first and second oxygen gas supply paths and the hydrogen gas supply path to inject each gas to the upper portion of the body through the fine nozzles.

In this case, the fine nozzles are preferably arranged concentrically around the central chamber nozzle, and the fine nozzles for the first and second oxygen gas supply paths and the hydrogen gas supply path are alternately arranged in two or more rows, respectively. Also preferred.

In addition, the fine nozzle may be connected to the pinhole extending by a predetermined length in a predetermined direction to the inside of the body so that the flame generated on the upper portion of the body has a direction.

In addition, a filter may be installed inside the first and second oxygen gas supply paths and the hydrogen gas supply path to prevent local concentration of the injection pressure, and the filter may be a silica glass filter having a porosity of 50 to 150 μm. Preferably, the filter is a silica glass filter having a porosity of 100 ~ 120μm.

According to another aspect of the present invention, a cylindrical body, a central chamber disposed in the center of the body and a spiral flow path is formed therein, at a predetermined interval between the central chamber, the central chamber for mixing the glass raw material and oxygen to supply to the upper portion of the body A second oxygen gas installed to surround the first oxygen gas supply path for supplying the oxygen gas to the upper part of the body and the first oxygen gas supply path at a predetermined interval to supply the oxygen gas to the upper part of the body A supply path, and a hydrogen gas supply path installed to surround the second oxygen gas supply path at predetermined intervals to supply hydrogen gas to the upper portion of the body, the central chamber, the first and second oxygen gas supply paths, and Nozzles for gas injection are respectively formed at the upper end of the hydrogen gas supply path, and the nozzles are formed in concentric circles around the central chamber nozzle. Is value.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 and 2 are views showing the configuration of a burner for preparing fine powder for silica particle deposition according to the present invention, respectively. Referring to the drawings, the burner 10 for producing fine powder of the present invention has a substantially cylindrical body 11, the cylindrical body 11 is composed of a multi-layer independent chamber to be described later. In addition, the upper cover 12 is installed on the upper end of the body 11, the upper cover 12 may be installed independently for each independent chamber, or may be made of a single body covering all the independent chambers at once. In some cases, the top cover 12 may not be used.

In the center of the body 11 is disposed a central chamber 30 for supplying the glass raw material and oxygen gas. The central chamber 30 traverses up and down the center of the body 11, and the inlet pipes 20 and 22 for introducing the glass raw material gas and the oxygen gas are installed at the lower end thereof. When the doping material is to be supplied in the silica particle deposition process, an inlet tube 24 for the doping material may be additionally installed at the lower end of the central chamber 30.

The central chamber nozzle 32 is formed at the upper end of the central chamber 30. The nozzle 32 serves to eject the mixed gas supplied through the central chamber 30 to the upper portion of the cylindrical body 11. Preferably, the central chamber nozzle 32 is located at the center of the top surface of the cylindrical body 11.

At this time, the spiral chamber 34 for mixing the glass raw material gas and oxygen gas introduced into the central chamber 30 may be formed. The spiral passage 34 may be manufactured by forming a spiral protrusion on the inner wall of the central chamber 30, or installing a spiral blade in the central chamber 30. In general, although the mixed gas passing through the central chamber 30 is partially mixed by its own flow, the natural flow alone does not guarantee uniform mixing of the glass raw material gas and the oxygen gas. However, when the spiral flow path 34 is formed in the central chamber 30 as described above, the glass raw material gas and the oxygen gas pass through the spiral flow path 34 to form a strong whirlpool vortex. When the mixture is mixed and eventually ejected to the top of the burner 10 through the nozzle 32, it is possible to maintain a constant mixing ratio at all times. This is an important factor for achieving a uniform deposition effect when manufacturing the preform for the optical fiber in the future.

The central chamber 30 may also be provided with a central chamber heater 36. The glass raw material gas introduced into the central chamber 30 in a gaseous state may change into a liquid phase when the temperature decreases while passing through the central chamber 30. The glass raw material turned into a liquid phase may be sprayed in a drop form when it is sprayed through the nozzle 32, thereby causing deterioration of the quality of the preform. Therefore, the heating device 36 for the central chamber keeps the glass raw material from liquefying by maintaining the temperature in the central chamber 30 at a predetermined temperature or more. In particular, since the mixed gas introduced into the central chamber 30 has a tendency to decrease in temperature as the flow rate increases, the heating device 36 changes the heating temperature according to the flow rate of the mixed gas, or the flow rate is higher than a predetermined reference. Can only be controlled to perform the heating function. Through this process, the heating device 36 prevents the liquefaction of the glass raw material to prevent the soot generation efficiency from lowering, and also prevents the flame temperature from lowering.

The first oxygen gas supply path 40 is disposed around the central chamber 30. The first oxygen gas supply path 40 is composed of a chamber independent from the central chamber 30, and a first oxygen gas inlet pipe 41 for introducing oxygen gas is connected to one lower side thereof. A plurality of fine nozzles 42 are installed at the upper end of the first oxygen gas supply path 40 to eject oxygen gas introduced into the first oxygen gas inlet pipe 41 to the upper portion of the burner 10. At this time, the oxygen gas supplied through the first oxygen gas supply path 40 is partially supplied to the mixed gas ejected from the central chamber 30 to assist combustion, and the mixed gas is diffused to the outside so that the soot is burner 10. ) To prevent adhesion to the surface. That is, the oxygen gas closer to the center of the oxygen gas supplied from the first oxygen gas supply path 40 participates in the oxidation reaction of oxygen (O ₂ ) injected from the central chamber 30, but the oxygen gas close to the outer circumferential surface is By oxidizing prematurely by the flame generated on the outer circumferential surface, the soot is generated and prevented from being deposited on the surface of the burner in advance. Accordingly, the amount of oxygen gas supplied to the first oxygen gas inlet pipe 41 is mixed with the mixed gas ejected from the central chamber 30 in consideration of the above-described aspects, and the generated soot adheres to the burner 10 surface. It is desirable to determine it in an amount sufficient to prevent it.

The fine nozzle 42 is disposed in a circle around the nozzle 32 for the central chamber at the upper surface of the burner 10. The fine nozzles 42 have a smaller diameter than the central chamber nozzles 32, are arranged in two or more circles, and the fine nozzles 42 in each row are alternately arranged as shown in FIG. The structure of the fine nozzle 42 makes a uniform oxygen gas region around the mixed gas injected from the nozzle 32 for the central chamber, and in particular, the uniformity of the ejected oxygen gas due to the staggered arrangement of the fine nozzles 42. The castle is maximized.

The first oxygen gas supply path 40 is further provided with an oxygen gas filter 44 under the fine nozzle 42. In general, the gas injected in the multi-layer chamber is asymmetrically biased at the top of the burner due to the pressure injected in each chamber. This is usually because when the gas is injected, the pressure difference between the gas pressure before being ejected and the gas pressure after being ejected is so large that local concentration of pressure occurs. However, if the filter 44 is installed just below the fine nozzle 42 as described above, the pressure of the gas is uniformly distributed during the passage of the filter 44 so that the local pressure during the passage of the fine nozzle 42 is achieved. This can prevent the phenomenon of concentration.

It is preferable to use a glass filter (Glass filter) as the filter 44, fine pores are formed in the glass filter itself to perform a filtering function through the pores. At this time, the pore size of the glass filter 44 has a close relationship with the injection pressure of the gas. If the pore size is too small, the flow of the gas is blocked to raise the pressure inside the burner more than necessary. If the pore size is too large, the filtering effect is reduced too much. Therefore, the pore size of the glass filter 44 is preferably about 80 ~ 150μm, more preferably about 100 ~ 120μm pore size.

A pin hole 46 may also be formed below the fine nozzle 42. The pinhole 46 extends by a predetermined length from the upper surface of the burner 10 to the inside of the burner 10 and is connected to each of the fine nozzles 42. When the filter 44 is installed, the pinhole 46 is preferably disposed above the filter 44. The pinhole 46 induces a flow of oxygen gas ejected to the upper portion of the burner 10 through the fine nozzle 42, for which the pinhole 46 has an appropriate direction. That is, the oxygen gas passing through the fine nozzle 42 has a constant directionality by setting the direction of the pinhole 46. The direction of oxygen gas is determined by the type of flame desired, deposition intensity, flame temperature and other conditions. It is preferable that the length of the pinhole 46 is about 1-10 mm, More preferably, it has a length of about 2-6 mm. If the pinhole 46 is too short, the property of inducing gas flow is degraded, and if the pinhole 46 is too long, the pressure of the pinhole 46 rises.

The second oxygen gas supply path 50 is disposed outside the first oxygen gas supply path 40. The second oxygen gas supply path 50 is composed of a chamber independent from the central chamber 30 and the first oxygen gas supply path 40, and a second oxygen gas inlet pipe 51 for introducing oxygen gas to one side of the lower part. Is connected. Similarly to the first oxygen gas supply path 40, a plurality of fine nozzles 52 are installed at the upper end of the second oxygen gas supply path 50 to supply the oxygen gas introduced into the second oxygen gas inlet pipe 51. Blows off to the top of the burner (10). At this time, the oxygen gas supplied through the second oxygen gas supply path 50 may react as an oxidizing agent of the glass raw material supplied from the central chamber 30, but substantially does not contain oxygen (Combustion supporting gas) required to make a flame. The role of supply is more important. Therefore, the amount of oxygen gas supplied through the second oxygen gas inlet pipe 51 is determined to be an amount capable of keeping the temperature of the flame generated by the burner 10 constant.

The fine nozzle 52 is circularly disposed around the fine nozzle 42 for the first oxygen gas supply path on the upper surface of the burner 10. The fine nozzle 52 has a diameter smaller than that of the central chamber nozzle 32, similarly to the above-described fine nozzle 42 for oxygen gas supply path, is arranged in two or more rows, and the fine nozzles 52 in each row. ) Are staggered from each other as shown in FIG. 3. The structure of the fine nozzle 52 makes an additional uniform oxygen gas region around the oxygen gas injected from the first oxygen gas supply fine nozzle 42. In addition, the staggered arrangement of the fine nozzles 52 is for making the oxygen gas ejected uniform.

In the second oxygen gas supply path 50, an oxygen gas filter 54 is provided below the fine nozzle 52, similarly to the first oxygen gas supply path 40. The filter 54 installed directly under the fine nozzle 52 uniformly distributes the pressure of the gas passing through the filter 54 to prevent local pressure from being concentrated while the gas passes through the fine nozzle 52. do.

It is preferable to use a glass filter (Glass filter) as the filter 54, the pore size of the glass filter 54 is preferably about 80 ~ 150μm, similar to the filter 44 for the first oxygen gas supply path, more Preferably it has a pore size of about 100 ~ 120μm.

A pin hole 56 may also be formed below the fine nozzle 52. The pinhole 56 extends by a predetermined length from the upper surface of the burner 10 to the inside of the burner 10 like the pinhole 46 for the first oxygen gas supply path, and is connected to each of the fine nozzles 52. . When the filter 54 is installed, the pinhole 56 is preferably disposed above the filter 54. The pinhole 56 induces a flow of oxygen gas ejected to the upper portion of the burner 10 through the fine nozzle 52. To this end, the pinhole 56 has an appropriate directionality, whereby the oxygen gas passing through the fine nozzle 52 has a constant directionality. The direction of oxygen gas is determined by the type of flame desired, deposition intensity, flame temperature and other conditions. It is preferable that the length of the pinhole 56 is about 1-10 mm, More preferably, it has a length of about 2-6 mm.

The hydrogen gas supply path 60 is disposed outside the second oxygen gas supply path 50. The hydrogen gas supply path 60 is composed of a chamber independent from the central chamber 30 and the first and second oxygen gas supply paths 40 and 50, and introduces a combustible gas such as hydrogen gas into one lower side. Hydrogen gas inlet pipe 61 is connected to. Hydrogen gas flowed into the hydrogen gas inlet pipe 61 by installing a plurality of fine nozzles 62 at the upper end of the hydrogen gas supply path 60 similarly to the first and second oxygen gas supply paths 40 and 50. To the top of the burner (10). At this time, the hydrogen gas supplied through the hydrogen gas supply path 60 is for supplying heat required for the reaction, and has a flame having a temperature sufficient for the reaction with the oxygen gas supplied to the second oxygen gas supply path 50. Will be provided.

The fine nozzle 62 is circularly disposed around the fine nozzle 52 for the second oxygen gas supply path on the upper surface of the burner 10. The fine nozzles 62 have a diameter smaller than that of the central chamber nozzles 32, similarly to the above-described fine nozzles 42 and 52 for the first and second oxygen gas supply paths, and are arranged in two or more rows and are circular. The fine nozzles 62 in rows are staggered from one another as shown in FIG. 3. The structure of the fine nozzle 62 makes a uniform hydrogen gas region around the second nozzle for supplying oxygen gas. The staggered arrangement of the fine nozzles 62 is for making the hydrogen gas ejected uniform.

The hydrogen gas supply path 60 is further provided with a hydrogen gas filter 64 under the fine nozzle 62 similarly to the first and second oxygen gas supply paths 40 and 50. The filter 64 installed directly under the fine nozzle 62 can uniformly distribute the pressure of the gas passing through the filter 64 to prevent local pressure from being concentrated while the gas passes through the fine nozzle 62. Will be.

It is preferable to use a glass filter (Glass filter) as the filter 64, the pore size of the glass filter 64 is about 80 ~ 150μm, similar to the first and second oxygen gas supply path filter (44, 54) It is preferred, and more preferably has a pore size of about 100 ~ 120μm.

A pin hole 66 may also be formed below the fine nozzle 62. The pinhole 66 extends by a predetermined length from the upper surface of the burner 10 to the inside of the burner 10, similarly to the pinholes 46 and 56 for the first and second oxygen gas supply paths, respectively. ) Are connected to each other. When the filter 64 is installed, the pinhole 66 is preferably disposed above the filter 64. The pinhole 66 induces a flow of hydrogen gas ejected to the upper portion of the burner 10 through the fine nozzle 62. To this end, the pinhole 66 has an appropriate directionality, whereby the hydrogen gas passing through the fine nozzle 62 has a constant directionality. The direction of hydrogen gas is determined by the type of flame desired, deposition intensity, flame temperature and other conditions. It is preferable that the length of the pinhole 66 is about 1-10 mm, More preferably, it has a length of about 2-6 mm.

FIG. 3 shows the arrangement of the nozzles 32, 42, 52, 62 in the burner 10 of the present invention configured as described above. As shown in FIG. 3, the fine nozzles 42, 52, and 62 of the respective supply paths 40, 50, and 60 on the upper surface of the body of the burner 10 are disposed concentrically about the nozzle 32 for the central chamber. It can be seen that. The nozzles 32, 42, 52, and 62 are spaced apart from each other at regular intervals to inject gases independently from each other, but perform complementary functions. In addition, the gas order supplied from the burner 10 of the present invention is very important in consideration of the conversion efficiency of the silica particles and the deposition on the burner surface, and particularly, the first oxygen gas supply path 40 adjacent to the central chamber 30. Oxygen gas is supplied from the oxygen gas from the mixed gas supplied from the central chamber 30 to supplement the role of maintaining the temperature of the flame and at the same time performs a blocking function to prevent the deposition of the burner surface of the silica particles Done. Therefore, by using the oxygen gas as the blocking gas in this way, not only can the flame temperature be lowered, but also the soot is attached to the burner to prevent growth. In addition, the oxygen gas supplied from the second oxygen gas supply path 50 is mainly used to maintain the temperature of the flame, and the hydrogen gas supply path 60 generates a flame to generate a condition that may cause oxidation and hydrolysis reactions. Used to provide In addition, the fine nozzles 42, 52, and 62 of each supply path are alternately arranged in two or more rows, respectively, so that the gas injected from the same circumference can be uniformly maintained. ) Helps gases through each of the supply paths 40, 50, and 60 simultaneously play more than one role.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

For example, the first oxygen gas inlet tube 40 and the second oxygen gas inlet tube 50 which perform the same role of supplying oxygen in the above-described fine powder burner of the present invention may be integrated into one path. have. This modified configuration is shown in FIG. 4 is the same as the burner shown in FIGS. 1 to 3, but only an oxygen gas that supplies oxygen gas to the first oxygen gas nozzle 42 and the second oxygen gas nozzle 52 inside the burner. There is a difference in that the inlet pipe 100 consists of one path. Although this variant differs in the path for supplying the oxygen gas, the arrangement of each nozzle 32, 42, 52, 62 is substantially the same as that shown in FIG. Therefore, the present modified example performs substantially the same function as the burners shown in FIGS. 1 to 3, and substantially the same effect can be obtained.

The fine powder burner for depositing silica particles according to the present invention as described above has a very high conversion efficiency from flame to soot because gas phase mixing is performed first in the central chamber even if the flow rate of the source gas is increased. In case of using a dopant, the dopant may be uniformly distributed in the sprayed soot particles.

In addition, since the heating device is installed in the central chamber together, the temperature in the central chamber can be kept constant, and even if the flow rate of the raw material gas increases, the internal temperature decreases so that the raw material gas does not liquefy. No nozzle contamination due to liquefaction occurs.

In addition, a filter installed in each supply path helps to simplify the overall structure of the burner while suppressing partial concentration of gas pressure, so that a uniform gas flow can be obtained at the burner nozzle, which is particularly effective when increasing the flow rate of the gas. . The uniform gas injection also affects the flight trajectory of the particles, and thus has the advantage of obtaining uniformity of the preform.

In addition, the burner of the present invention supplies gas in the order of mixed gas, oxygen gas, oxygen gas, and hydrogen gas from an independent chamber, so that the gases from each chamber perform complementary functions with each other, thereby improving deposition efficiency of silica particles. Of course, various problems that have been raised conventionally have been overcome. In particular, the oxygen gas ejected from the first oxygen gas supply path adjacent to the central chamber assists in the oxidation of the mixed gas and simultaneously serves as a blocking gas to prevent flame temperature drop and to prevent the soot from adhering to the burner. Oxygen gas ejected from the second oxygen gas supply path disposed in the serves to maintain a constant temperature of the flame, hydrogen gas also provides a condition that can form a flame to cause oxidation and hydrolysis reaction Each gas is linked to each other to increase the deposition efficiency of the silica particles.

In addition, since the fine nozzles arranged in two or more rows are used for the oxygen gas and the hydrogen gas ejection, it is possible not only to provide a uniform gas concentration but also to perform each role more effectively.

Claims (25)

Cylindrical body 11; A central chamber 30 formed at the center of the body to supply a mixed gas of glass raw material and oxygen to the upper portion of the body; A first oxygen gas supply path 40 installed to surround the central chamber at predetermined intervals to supply oxygen gas to an upper portion of the body; A second oxygen gas supply path 50 installed to surround the first oxygen gas supply path at predetermined intervals to supply oxygen gas to an upper portion of the body; And And a hydrogen gas supply path (60) installed to surround the second oxygen gas supply path at a predetermined interval to supply hydrogen gas to an upper portion of the body. The method of claim 1, The central chamber (30) is burner for producing fine powder for the deposition of silica particles, characterized in that the spiral channel 34 is formed to improve the mixing of the mixed gas therein. The method of claim 2, Burner for fine powder deposition for silica particles, characterized in that the central chamber (30) is provided with a means (36) for heating the central chamber (30) to prevent the liquefaction of the mixed gas. The method of claim 3, The central chamber heating means (36) is a fine powder burner for silica particle deposition, characterized in that the heating coil is installed around the central chamber (30). The method of claim 2, The central chamber 30 is a fine powder burner for depositing silica particles, characterized in that for supplying a mixture of the doping material with a glass raw material gas and oxygen gas. The method of claim 1, The amount of oxygen supplied from the first oxygen gas supply path 40 is mixed with the mixed gas supplied from the central chamber 30, but maintained so that a soot does not adhere to the upper surface of the body 11. Burner for preparing fine powder for silica particle deposition. The method of claim 1, The amount of oxygen supplied from the second oxygen gas supply path (50) is controlled to maintain the temperature of the flame generated on the body (11) to a fine powder burner for the deposition of silica particles. The method according to any one of claims 1 to 7, The first and second oxygen gas supply path (40, 50) and the hydrogen gas supply path (60) is a burner for producing fine powder for silica particle deposition, characterized in that each consisting of a separate chamber. The method of claim 8, A plurality of fine nozzles 42, 52, and 62 are formed at an upper end of the first and second oxygen gas supply paths 40 and 50 and the hydrogen gas supply path 60, respectively. Burner for preparing fine powder for silica particle deposition, characterized in that the injection to the top of the body (11). The method of claim 9, The fine nozzle (42, 52, 62) is a fine powder burner for the deposition of silica particles, characterized in that arranged in a concentric circle around the center chamber nozzle (32). The method of claim 10, Silica particles, characterized in that the fine nozzles 42, 52, 62 for the first and second oxygen gas supply paths 40, 50 and the hydrogen gas supply path 60 are alternately arranged in two or more rows. Burner for preparing fine powder for evaporation. The method of claim 11, The fine nozzles 42, 52, and 62 are pinholes 46, 56, and 66 extending by a predetermined length in a predetermined direction to the inside of the body 11 such that the flame generated on the body 11 has a directionality. Burner for preparing fine powder for silica particle deposition, characterized in that connected. The method of claim 9, Filters 44, 54, and 64 are installed in the first and second oxygen gas supply paths 40 and 50 and the hydrogen gas supply path 60 to prevent local concentration of injection pressure. Burner for preparing fine powder for silica particle deposition. The method of claim 13, The filter (44, 54, 64) is a fine powder burner for silica particle deposition, characterized in that the silica glass filter having a porosity of 50 ~ 150μm. The method of claim 13, The filter (44, 54, 64) is a fine powder burner for silica particle deposition, characterized in that the silica glass filter having a porosity of 100 ~ 120μm. Cylindrical body 11; A central chamber (30) disposed at the center of the body and having a spiral flow path (34) formed therein to mix glass raw material and oxygen and to supply the upper portion of the body; A first oxygen gas supply path 40 installed to surround the central chamber at predetermined intervals to supply oxygen gas to an upper portion of the body; A second oxygen gas supply path 50 installed to surround the first oxygen gas supply path at predetermined intervals to supply oxygen gas to an upper portion of the body; And A hydrogen gas supply path 60 installed to surround the second oxygen gas supply path at a predetermined interval to supply hydrogen gas to an upper portion of the body, Nozzles 32, 42, 52, and 62 for gas injection are respectively disposed on the upper ends of the central chamber 30, the first and second oxygen gas supply paths 40 and 50, and the hydrogen gas supply path 60. Formed, The nozzle is a fine powder burner for depositing silica particles, characterized in that arranged in a concentric circle around the nozzle for the central chamber (32). The method of claim 16, The nozzles 42, 52, and 62 for the first and second oxygen gas supply paths 40 and 50 and the hydrogen gas supply path 60 are disposed in two or more rows, respectively, and two or more rows for each path. Burner for preparing fine powder for silica particle deposition, characterized in that the nozzles (42, 52, 62) are alternately arranged. The method of claim 17, A burner for preparing fine powder for silica particle deposition, characterized in that a filter (44, 54, 64) is installed below the nozzle (42, 52, 62) to prevent local concentration of the injection pressure. The method of claim 18, The filter (44, 54, 64) is a fine powder burner for silica particle deposition, characterized in that the silica glass filter having a porosity of 50 ~ 150μm. The method of claim 18, The filter (44, 54, 64) is a fine powder burner for silica particle deposition, characterized in that the silica glass filter having a porosity of 100 ~ 120μm. Cylindrical body 11; A central chamber 30 formed at the center of the body to supply a mixed gas of glass raw material and oxygen to the upper portion of the body; An oxygen gas supply path 100 installed to surround the central chamber at predetermined intervals and supply oxygen gas to an upper portion of the body; And It is installed so as to surround the oxygen gas supply path at a predetermined interval and includes a hydrogen gas supply path 60 for supplying hydrogen gas to the upper portion of the body, The central nozzle 32 for the injection of the mixed gas is formed at the upper end of the central chamber 30, The first oxygen gas nozzle 42 and the second oxygen gas nozzle 52 for the injection of oxygen gas is formed on the upper end of the oxygen gas supply path 100, The first oxygen gas nozzle is arranged concentrically around the center nozzle around the central nozzle, and the second oxygen gas nozzle is concentrically around the central nozzle around the first oxygen gas nozzle. Will be placed, Hydrogen gas nozzle 62 for the injection of hydrogen gas is formed at the upper end of the hydrogen gas supply path 60, The hydrogen gas nozzle is a fine powder burner for depositing silica particles, characterized in that arranged in a concentric circle around the center nozzle around the second oxygen gas nozzle. The method of claim 21, The nozzles 42, 52, and 62 for the first and second oxygen gas supply paths 40 and 50 and the hydrogen gas supply path 60 are disposed in two or more rows, respectively, and two or more rows for each path. Burner for preparing fine powder for silica particle deposition, characterized in that the nozzles (42, 52, 62) are alternately arranged. The method of claim 22, A burner for preparing fine powder for silica particle deposition, characterized in that a filter (44, 54, 64) is installed below the nozzle (42, 52, 62) to prevent local concentration of the injection pressure. The method of claim 23, wherein The filter (44, 54, 64) is a fine powder burner for silica particle deposition, characterized in that the silica glass filter having a porosity of 50 ~ 150μm. The method of claim 23, wherein The filter (44, 54, 64) is a fine powder burner for silica particle deposition, characterized in that the silica glass filter having a porosity of 100 ~ 120μm.