JP2007126340A - Method for manufacturing deposited body of glass fine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a deposited body of a glass fine particle under excellent manufacturing conditions by preventing the degradation of the tip of a burner while cutting down the expense of an inert gas or nitrogen gas to reduce the manufacturing cost of a product. <P>SOLUTION: The method for manufacturing the deposited body 19 of the glass fine particle comprises the steps of: producing a glass fine particle by using the burner 7 provided with: a port P1 arranged in the center for jetting a gaseous glass raw material; ports P2, P4 arranged outside the port P1 for jetting combustible gas; and ports P3, P5 arranged outside the port P1 for jetting a combustion supporting gas; and depositing the produced glass fine particle on a glass rod 11. When the distance between the port for the combustible gas and the adjacent port for the combustion supporting gas (the thickness of a pipe 32b, a pipe 32c or a pipe 32d) is defined as W (mm) and the flow rate of the combustible gas to be jetted from the port for the combustible gas is defined as V (m/second), the flow velocity V of the combustible gas is made to satisfy 0.3&le;V/W and kept to the extent that the burner 7 does not reach a red-hot state. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention uses a glass synthesis burner that generates glass fine particles in an oxyhydrogen flame by ejecting a glass raw material gas, a combustible gas, and a combustion-supporting gas. The present invention relates to a method for producing a glass particulate deposit to be formed.

  An example of a glass product is an optical fiber. An optical fiber preform for obtaining an optical fiber is a glass particulate deposit by depositing glass particulates (called soot) generated by a vapor phase synthesis method on a starting rod. It is obtained by dehydrating and sintering to form a transparent glass. As a method of forming this glass fine particle deposit, there is a method in which the glass fine particles generated by the glass synthesis burner are deposited in the radial direction or the axial direction of the starting rod while rotating the long starting rod around the axis. is there.

  As an example of a method for producing a glass particulate deposit using such a glass synthesis burner, a mixed gas obtained by adding an inert gas or nitrogen gas to hydrogen gas and an oxygen gas are respectively supplied from ports adjacent to the burner. It is known to supply (for example, refer to Patent Document 1).

JP 11-79774 A

  By the way, the burner for glass synthesis reacts the jetted combustible gas and the combustion-supporting gas to generate an oxyhydrogen flame in the vicinity of the burner tip. Therefore, the tip of the burner deteriorates due to the heat of the flame. . In the above-mentioned Patent Document 1, by supplying a mixed gas obtained by adding an inert gas or nitrogen gas to hydrogen gas, the hydrogen gas is diluted and an oxyhydrogen flame is formed in a portion away from the nozzle tip of the burner. Although it is described that deterioration of the burner tip is suppressed, the use of a large amount of inert gas or nitrogen gas increases the cost, and a separate gas supply facility is required. Furthermore, dilution of the hydrogen gas lowers the temperature of the oxyhydrogen flame and makes the flame unstable, and the glass particle generation efficiency tends to decrease, and the deposition surface temperature decreases and the deposition conditions change. End up.

  Accordingly, an object of the present invention is to reduce the cost of using an inert gas or nitrogen gas, to suppress the manufacturing cost of the product, to prevent deterioration of the burner tip, and to manufacture a glass particulate deposit under favorable manufacturing conditions. It is an object of the present invention to provide a method for producing a glass fine particle deposit capable of being applied.

  The method for producing a glass particulate deposit according to the present invention that can solve the above-described problems is a glass raw material gas port that is disposed in the center and ejects a glass raw material gas, and is disposed outside the glass raw material gas port and is combustible. Glass fine particles are generated by a glass synthesis burner equipped with a combustible gas port for injecting gas, and a port for inflammable gas that is disposed outside the glass raw material gas port and injects inflammable gas. A method for producing a glass fine particle deposit by depositing glass fine particles on a rod to form a glass fine particle deposit, wherein the distance between the adjacent combustible gas port and the combustion-supporting gas port is W (mm) , When the flow rate of the combustible gas ejected from the combustible gas port is V (m / min), the flow rate V of the combustible gas is in a relationship satisfying 0.3 ≦ V / W, and Serial glass synthesizing burner is characterized in that the flow rate is not red hot.

  In the method for producing a glass fine particle deposit according to the present invention, it is preferable that the material of the burner for glass synthesis is quartz and V / W ≦ 5 is satisfied.

  Further, in the method for producing a glass particulate deposit according to the present invention, an inert gas that has a vacant port between the adjacent flammable gas port and the flammable gas port, and is ejected from the vacant port. Alternatively, the flow rate of the nitrogen gas is preferably 5% by volume or less of the flow rate of the combustible gas ejected from the adjacent combustible gas port.

  According to the method for producing a glass particulate deposit according to the present invention, the ratio of the flow velocity V of the combustible gas ejected from the combustible gas port to the distance W between the adjacent combustible gas port and the support gas port. 0.3 or more, the distance W between the flammable gas port and the flammable gas port is not too wide, and the reaction between the flammable gas and the flammable gas is favorably performed. The flow rate V of the combustible gas is ensured so as to stabilize the flame. Therefore, the temperature of the oxyhydrogen flame and the temperature of the deposition surface on which the glass fine particles are deposited can be maintained to improve the generation efficiency of the glass fine particles, and the glass fine particle deposit can be produced under good production conditions. Furthermore, since the flow velocity V of the combustible gas is suppressed so that the glass synthesis burner does not become red hot, deterioration of the burner tip can be suppressed. Therefore, deterioration of the burner tip can be suppressed without the need to use a large amount of inert gas or nitrogen gas, and the manufacturing cost of the product can be suppressed.

  Hereinafter, an example of an embodiment of a method for producing a glass fine particle deposit according to the present invention will be described with reference to the drawings. In the present embodiment, a VAD method will be described as an example of a method for manufacturing a glass fine particle deposit.

FIG. 1: has shown the schematic of the manufacturing apparatus which can implement the manufacturing method of the glass fine particle deposit body based on this invention, (a) is a schematic front view, (b) has shown the figure seen from the bottom face. .
As shown in FIG. 1, the glass particle deposit manufacturing apparatus 10 includes a reaction vessel 1, and an opening / closing plate 5 having an expandable / contractible opening 5 a is provided on the upper portion of the reaction vessel 1. Yes. A suspending device 13 is installed on the outer upper side of the reaction vessel 1, and the seed bar 12 is suspended by the suspending device 13. A glass rod 11 is attached to the suspended seed rod 12, and the glass rod 11 is introduced into the reaction vessel 1 through the opening 5a.

The suspension device 13 allows the glass rod 11 attached to the seed rod 12 to be axially rotated and moved in the axial direction. Moreover, the suspending device 13 is configured so that the movement speed of the glass rod 11 in the axial direction can be changed.
When glass particles are deposited on the outer periphery of the glass rod 11, a glass particle deposit 19 having the glass rod 11 at the center can be produced.
At the lower part of the reaction vessel 1, a burner (glass synthesis burner) 7 for generating glass particles and an exhaust port 9 for discharging undeposited glass particles in the reaction vessel 1 are provided.

The burner 7 has a multi-port structure in which a gas outlet has a plurality of ports, and a combustion gas or a glass raw material gas is blown out from each port, and the glass raw material is oxidized in a flame generated by the combustion gas. Glass particles are produced by reaction or hydrolysis reaction. Here, the combustion gas supplied to the burner 7 mainly includes a combustible gas and a combustion-supporting gas, and examples of the combustible gas include hydrogen and examples of the combustion-supporting gas include oxygen. An example of the glass raw material gas is silicon tetrachloride (SiCl ₄ ).

In FIG. 2, the schematic front view of the burner for glass synthesis used for this embodiment is shown.
As shown in FIG. 2, the burner 7 includes a plurality of cylindrical pipes 32a, 32b, 32c, 32d, and 32e having different diameters arranged concentrically.

  In the burner 7 provided with these pipes 32a, 32b, 32c, 32d, and 32e, the inner space of the pipe 32a at the center is formed as a port P1 for blowing out glass raw material gas, and each pipe 32a, 32b, The gaps 32c, 32d and 32e are formed as ports P2, P3, P4 and P5 from the inside, respectively. The material of the pipes 32a, 32b, 32c, 32d, and 32e constituting the burner 7 is quartz, but may be a metal.

The burner 7 is connected to piping for supplying combustion gas and glass raw material gas to the ports P1 to P5, and gas flow controllers 15, 16, and 17 are attached to the middle of the piping. The combustion gas and the glass raw material gas can be separately supplied to the ports P1 to P5 of the burner 7.
In the present embodiment, the port P1 disposed at the center is a glass raw material gas port for ejecting glass raw material gas, and the ports P2 and P4 disposed outside the port P1 are combustible for ejecting combustible gas. It is a gas port, and ports P3 and P5 arranged outside the port P1 are ports for combustion-supporting gas for ejecting combustion-supporting gas.

  In addition, a projector 2 is provided outside the reaction vessel 1 toward the bottom surface of the glass particulate deposit 19 formed by the burner 7, and receives light at a position where the light beam 18 from the projector 2 can be received. A container 3 is arranged (see FIG. 1B). The position of the deposition surface of the glass particulate deposit 19 is detected by the projector 2 and the light receiver 3. The light receiver 3 is connected to the control device 4 via a line 21. Further, the control device 4 is connected to the suspension device 13 via a line 25.

Next, a method for manufacturing a glass particulate deposit using this manufacturing apparatus 10 will be described below.
First, the glass rod 11 is attached to the tip of the seed rod 12, and the seed rod 12 is suspended from the suspension device 13. Then, the suspension device 13 is operated, and the glass rod 11 is lowered so that the distance between the glass particle 11 deposition start point of the glass rod 11 and the outlet of the burner 7 becomes a desired distance.
On the other hand, the gas flow controllers 15, 16, and 17 supply combustion-supporting gas (oxygen), combustible gas (hydrogen), and glass raw material gas (silicon tetrachloride) to the ports P 1 to P 5 of the burner 7.

  The glass rod 11 is rotated about its axis, and an oxyhydrogen flame is emitted from the burner 7 toward the glass rod 11. In this oxyhydrogen flame, glass fine particles are generated by an oxidation reaction or hydrolysis reaction of silicon tetrachloride. The glass rod 11 is pulled up at a predetermined speed while adhering the generated glass particles to the outer periphery of the glass rod 11, and the glass particle deposit 19 is gradually formed and grown.

  In this embodiment, the distance between adjacent flammable gas ports and the flammable gas ports (that is, the thickness of the pipes 32b, 32c, and 32d) is W (mm), and the flammable gas ports (ports). When the flow rate of the combustible gas ejected from P2, P4) is V (m / min), the flow rate V of the combustible gas is adjusted so as to satisfy the relationship of 0.3 ≦ V / W. As a result, the distance W between the combustible gas port and the combustion-supporting gas port is not excessively wide, and the reaction between the combustible gas and the combustion-supporting gas is satisfactorily performed and the oxyhydrogen flame is stabilized. The flow velocity V of combustible gas is secured. Therefore, the temperature of the oxyhydrogen flame can be maintained to improve the generation efficiency of the glass fine particles, and the temperature of the deposition surface on which the glass fine particles are deposited is not lowered, so that the manufacturing conditions of the glass fine particle deposit are not changed.

  Further, the flow rate V of the combustible gas is suppressed so that the glass synthesis burner does not become red hot. In the case of the present embodiment, the material of the pipes 32a, 32b, 32c, 32d, and 32e constituting the burner 7 is quartz, and V / W ≦ 5 is satisfied so that the burner 7 is not heated red by the heat of the oxyhydrogen flame. The flow velocity V of the combustible gas ejected from the ports P2 and P4 is suppressed. Note that the temperature at which the quartz glows red is about 1100 ° C. Thereby, deterioration of the front-end | tip part of the burner 7 can be suppressed without using inert gas, the service life of the burner 7 can be extended, and the manufacturing cost of a product can be held down.

Further, when the glass particles are deposited, the position of the deposition surface of the glass particle deposit 19 is detected by the projector 2 and the light receiver 3. The received light amount data detected by the light receiver 3 is sent to the control device 4, and the lifting speed of the glass rod 11 is controlled with respect to the suspension device 13 so that the received light amount becomes constant.
In this way, by adjusting the pulling speed of the glass rod 11, the outer diameter of the glass fine particle deposit 19 deposited on the glass rod 11 is deposited so as to be uniform over the longitudinal direction.

  In the above embodiment, an example in which no inert gas or nitrogen gas is used has been described. However, an inert gas or nitrogen gas may be used in the method for producing a glass particulate deposit according to the present invention. In that case, the burner which has a vacant port between the port for adjacent flammable gas and the port for flammable gas is used, and the flow rate of the inert gas or nitrogen gas ejected from the vacant port is adjacent. It is good to set it as 5 volume% or less of the flow volume of the combustible gas ejected from the port for combustible gases.

  For example, as shown in FIG. 3, a vacant port P6 is provided in a pipe 32d between a port P4 that is a flammable gas port and a port P5 that is a flammable gas port. A small amount of inert gas or nitrogen gas may be ejected. At that time, the flow rate of the inert gas or nitrogen gas is set to 5% by volume or less of the flow rate of the combustible gas ejected from the adjacent port P4.

  Thus, by flowing the inert gas or nitrogen gas at a slight flow rate compared to the combustible gas, the effect of lowering the temperature of the tip portion of the burner 7 can be sufficiently obtained, and the inert gas or nitrogen gas is applied. Costs can be kept extremely low. Further, at such a flow rate, the oxyhydrogen flame does not become unstable, and the temperature of the deposition surface on which the glass particles are deposited hardly decreases. Therefore, it is possible to manufacture the glass fine particle deposit 19 in a good state without changing the manufacturing conditions.

The glass synthesis burner used in the present invention is not limited to a circular cross section, and may be a rectangular cross section. Further, the multi-pipe structure may have any number of layers.
Furthermore, in the present embodiment, the burner 7 having a concentric multi-tube structure has been described as an example, but the glass synthesis burner used in the present invention may not be concentric. For example, like a burner 41 shown in FIG. 4, a port P8 as a combustible gas port for injecting a combustible gas around a pipe 42a forming a port P7 as a glass raw material gas port disposed in the center. In addition, a plurality of pipes 42c forming a port P9 as a port for supporting a combustion gas in the port P8 for ejecting a combustion supporting gas are arranged on the same circle. You may do it. In the burner 41, the plurality of pipes 42 c are disposed so as to be inclined toward the center with respect to the central axis of the burner 41 so that the focal point in the jetting direction overlaps one place on the central axis of the burner 41. . When the burner 41 having such a structure is used, the flame energy can be concentrated at a target position while suppressing the spread of the oxyhydrogen flame.

  In the above embodiment, the VAD method in which the glass particles 11 are deposited in the axial direction of the glass rod 11 while pulling up the glass rod 11 has been described as an example. However, the glass particles are deposited in a layered manner in the radial direction on the glass rod 11. It can also be applied to the OVD method.

  Glass fine particle deposits were manufactured by synthesizing glass fine particles with the burner 7 having a five-pipe structure shown in FIGS. Silicon tetrachloride is supplied to port P1, hydrogen is supplied to port P2 at a flow rate of 1.4 m / sec, oxygen is supplied to port P3 at a flow rate of 4.8 m / sec, and hydrogen is supplied to port P4. The gas was supplied at 5.6 m / sec, and oxygen was supplied to port P5 at a flow rate of 5.0 m / sec. Further, the distance between the ports P2 and P3 (that is, the thickness of the pipe 32b), the distance between the ports P3 and P4 (that is, the thickness of the pipe 32c), and the distance between the ports P4 and P5 (that is, the thickness of the pipe 32d) are 3 mm, respectively. did. When the glass fine particles were synthesized under such conditions, the temperature of the tip portion of the burner 7 was the highest between the ports P4 and P5 (pipe 32d) and was 710 ° C.

  Further, when the distance between the ports P4 and P5 is set to 1 mm and 3 mm, the hydrogen flow rate condition of the port P4 is changed, and the red heat state and the oxyhydrogen flame state (stability) of the tip portion of the burner 7 are changed. confirmed. The results are shown in Table 1. In Table 1, the flame stability is indicated by ◯ for a well-stabilized state, by Δ for a slightly disturbed state, and by × for an unstable state.

  As shown in Table 1, in Example 2, Example 3, Example 7, and Example 8 satisfying 0.3 ≦ V / W ≦ 5, the burner tip is not heated enough to become red hot, and the flame may become unstable. It is prevented. On the other hand, in Example 1, Example 5 and Example 6 in which V / W is less than 0.3, the flame state became unstable. In Examples 4 and 9 where V / W exceeded 5, the burner tip was red hot.

  Also, using a burner 41 provided with a port P6 (see FIG. 3) with a gap of 1 mm in the pipe 32d (thickness 3 mm) between the ports P4 and P5, glass particles are synthesized while jetting nitrogen gas from the port P6. did. And the nitrogen flow rate of port P6 was changed, and the red hot state and the state (stability) of the oxyhydrogen flame of the front-end | tip part of the burner 7 were confirmed. The results are shown in Table 2.

  When Example 10 and Example 11 shown in Table 2 are compared, the effect of lowering the temperature at the tip of the burner can be sufficiently obtained by flowing a very small amount (5%) of the nitrogen flow rate with respect to the hydrogen flow rate. It was confirmed that the surface temperature hardly changed. Further, as in Example 12, when nitrogen was flowed at a flow rate of 25% with respect to the hydrogen flow rate, the deposition surface temperature was greatly lowered, and the manufacturing conditions of the glass particulate deposits were greatly changed.

BRIEF DESCRIPTION OF THE DRAWINGS The manufacturing apparatus which can implement the manufacturing method of the glass fine particle deposition body which concerns on this invention is shown, (a) is a schematic front view, (b) is the figure seen from the bottom face. It is a front view of the burner shown in FIG. It is a fragmentary sectional enlarged view which shows the other example of a form of the burner shown in FIG. It is the elements on larger scale which show the other example of a form of the burner shown in FIG.

Explanation of symbols

7 Burner 4 Control device 10 Glass particle deposit manufacturing device 11 Glass rod (starting rod)
19 Glass particulate deposit P1-P9 Port

Claims (3)

A glass raw material gas port for ejecting glass raw material gas disposed in the center, a combustible gas port for ejecting combustible gas disposed outside the glass raw material gas port, and a glass raw material gas port. Production of glass particulate deposits in which glass particulates are generated by a glass synthesis burner equipped with a gas for combustion supporting gas jetting and a glass particulate deposit is formed by depositing glass particulates on a starting rod. A method,
When the distance between the adjacent flammable gas port and the flammable gas port is W (mm) and the flow rate of the flammable gas ejected from the flammable gas port is V (m / min) The method for producing a glass particulate deposit, wherein the flow rate V of the combustible gas satisfies a relationship satisfying 0.3 ≦ V / W, and the flow rate is such that the glass synthesis burner does not red heat.   The method for producing a glass fine particle deposit according to claim 1, wherein the glass synthesis burner is made of quartz and satisfies V / W≤5.   There is a vacant port between the adjacent flammable gas port and the flammable gas port, and the flow rate of the inert gas or nitrogen gas ejected from the vacant port is changed to the adjacent flammable gas port. The method for producing a glass particulate deposit according to claim 1 or 2, wherein the flow rate is 5% by volume or less of the flow rate of the combustible gas ejected from the glass.

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