JPH0930817A - Burner for glass formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the flame using LNG to be stabilized by providing turbulent flow-generating members to a third nozzle which jets LNG and surrounds a first nozzle jetting a raw material gas for producing glass and a second nozzle jetting oxygen. SOLUTION: Four nozzles 11 arranged on the center of a burner have each a double-tube structure to jet out a raw material gas for producing glass, namely a silicon tetrachloride and argon mixed gas. A nozzle 12 for jetting out argon gas is set so that it may annularly surround the nozzle 11 and twelve nozzles 13 for jetting out oxygen are arranged on the periphery of the nozzles 11 and 12. Another cylindrical nozzle 14 of a large diameter for jetting LNG is set so that it may surround these nozzles 11-13 to jet out LNG between nozzles 12, 13 and the like. The turbulent flow generator 21 of a lattice structure is arranged at the top position of the nozzle 14 so that the intersection points of the lattice structure come to the position of the nozzles 12, 23. The turbulent flow generator 21 is made of metallic round rods.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a burner that produces glass particles by a gas phase reaction.

[0002]

2. Description of the Related Art In the VAD method or the like for producing a glass base material for an optical fiber, glass raw material gas such as silicon tetrachloride is introduced into a flame to generate fine particles of glass (silicon dioxide) by a hydrolysis reaction. , Deposit this. A burner is used to generate the flame and cause a hydrolysis reaction. Combustion gas and raw material gas carried as a carrier gas are sent to the burner. Oxygen and hydrogen are generally used as the combustion gas.

By the way, in recent years, natural gas (hereinafter abbreviated as LNG) has been considered as an alternative fuel for hydrogen. This is because LNG is a liquid, is easy to store and manage, and has a low cost.

[0004]

SUMMARY OF THE INVENTION However, LNG
When using to create a flame, there is a problem that the flame is easily blown off. Since the combustion speed of LNG is slower than that of hydrogen, if the flow velocity of gas is set to be higher than a certain level, the flow velocity of LNG will exceed the combustion velocity, resulting in the situation where the flame is blown off and disappears. . For this reason, it is difficult to maintain a stable flame state required for deposition by using the burner that has been used conventionally as it is.

In this case, of course, if the flow rate of LNG is decreased, the blowout of the flame will be eliminated, but then the flow rate of LNG will be insufficient and the high temperature necessary for the glass formation reaction cannot be maintained, and stable glass fine particles will be formed. I can't. Also, in order to reduce the flow velocity while securing the flow rate,
It seems fine to increase the nozzle diameter, but if this is done, the flame will spread too much, and the device will become too large to be used in practice.

The present invention provides a burner for producing glass having an improved structure, which can maintain a stable flame state by using LNG as a combustion gas and thus can produce glass at low cost. With the goal.

[0007]

In order to achieve the above-mentioned object, in order to achieve the above-mentioned object, in a burner for glass production according to the present invention, a first nozzle for ejecting a glass raw material gas, A second nozzle for ejecting oxygen, a large cylindrical third nozzle for ejecting LNG surrounding the first and second nozzles, and a third nozzle provided near the ejection port of the third nozzle The turbulent flow generating material is provided.

Since LNG is ejected from the third nozzle and oxygen is ejected from the second nozzle arranged in the third nozzle, a flame is generated in the vicinity of the ejection port of the third nozzle. Then, since the glass raw material gas is fed into the flame from the first nozzle arranged in the third nozzle, glass fine particles are generated by the reaction in the flame. A turbulent flow generating material is attached to the ejection port of the third nozzle, and therefore, when LNG is ejected from this ejection port, a turbulent flow is generated. Therefore, this turbulent flow slows down the flow rate of LNG. As a result, it is possible to prevent the flame from blowing off while ensuring a sufficient LNG flow rate to keep the high temperature flame stable.

The above turbulent flow generating material is
It can also be used as a support material for holding and fixing the first and second nozzles.

Further, the turbulent flow generating material can be attached to a cap-shaped attachment body which is detachably attached to the tip of the third nozzle. This facilitates maintenance such as replacement of the turbulent flow generating material.

[0011]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially enlarged perspective view of the tip of the burner for producing glass according to the present invention (in the vicinity of the ejection port), FIG. 2 is a front view of this burner as seen from the ejection port side, and FIG. 3 is a schematic sectional view. As shown in these figures, the glass producing burner is configured as an assembly of a plurality of nozzles.

The four nozzles 11 located in the center are for jetting the raw material gas, and here, silicon tetrachloride and argon gas are jetted. A nozzle 12 for ejecting argon gas is provided so as to surround the nozzle 11 concentrically. And such a nozzle 1 having four concentric circle structures
12 nozzles 13 for ejecting oxygen are arranged around 1 and 12. And these nozzles 11, 12, 13
A cylindrical nozzle 14 having a large diameter is provided so as to surround the. This nozzle 14 is for jetting LNG, and jets LNG from the gap between the nozzles 12, 13 and the like.

As shown in FIG. 3, each of these gases is supplied from the rear end of the burner.

And here, these nozzles 12,
The turbulent flow generating materials 21 arranged in a grid pattern with the positions of 13 as intersections are attached to the tip portion of the nozzle 14. The turbulent flow generating material 21 can be composed of a round rod-shaped metal body or the like.

The LNG is the nozzle 1 of the nozzle 14.
Although it is ejected from the portion (the gap between them) excluding 2 and 13, it hits the turbulent flow generating material 21 in the shape of a round bar and produces turbulent flow.
Therefore, even if jetting is performed at a high flow velocity to secure the flow rate, the velocity is slowed by the turbulent flow. Therefore, the flame generated by the jetted LNG and oxygen becomes stable and is not blown away. Required LN
Since the G flow rate is secured, the flame temperature is sufficient. The glass raw material gas ejected from the nozzle 11 is introduced into this flame, so that the glass particles are stably generated.

As described above, the turbulent flow generation material 21 causes the LNG
A turbulent flow is generated in the turbulent flow, and the flow velocity is slowed down to form a stable flame. At the intersection of the grid, the assembly of nozzles 11 and 12 and the nozzle 1
Since the nozzles 3 are positioned, these nozzles are also supported by the turbulent flow generating material 21 and fixed in the nozzles 14. In this way, the turbulent flow generation material 2
1 is also used as a support material, and the nozzles 11 and 1
It is possible to prevent the positions 2 and 13 of the nozzle 14 from being displaced.

FIG. 4 is a schematic perspective view of another embodiment. Here, the turbulent flow generation material 21 is attached to the cap-shaped attachment body 22 in a grid pattern. The cap-shaped attachment body 22 is detachably attached to the tip of the nozzle 14. Therefore, here, the nozzles 11, 12, and 13 are not held by the turbulent flow generating material 21, but when a problem occurs, the cap-shaped mounting body 22 is attached to the nozzle 1.
4 can be easily removed from the tip and replaced with another one. When dirt or the like adheres to the turbulent flow generation material 21, if it is removed, the cleaning operation is easy. Further, by replacing the turbulent flow generating material 21 having another cross-sectional shape and cross-sectional size with the cap-shaped mounting body 22 having another arrangement density according to the flow condition of LNG, etc., the optimum one for the flow condition can be obtained. It can also be mounted as appropriate.

The above description is for the embodiment of the present invention, and can be variously modified. First, the turbulent flow generating material 21 is not limited to one having a circular cross section. The cross-sectional shape, the diameter size, and the like can be optimally selected according to the LNG flow rate conditions and the like. Turbulence generator 21
The arrangement of is not limited to the grid shape, and the number and the like are not limited to those illustrated. Next, the applied burner structure is not limited to the above. If the nozzle 11 for ejecting the glass raw material gas and the nozzle 13 for ejecting the oxygen are separated from each other to some extent or more, the nozzle 12 for ejecting the argon gas is unnecessary, and in addition, the positions and the number of the nozzles 11, 12, 13 are It is optional.

[0019]

EXAMPLES Further, specific examples will be described in detail. First, set the diameter of the nozzles 11 and 13 to 1 mm to 2 mm.
m, the diameter of the nozzle 12 is 3 mm to 4 mm, and the diameter of the nozzle 14 is 30 mm to 40 mm. In addition, the turbulent flow generation material 2
1 is composed of a round rod-shaped metal having a diameter of 1 mm. And
At the time of depositing the glass particles, 4 liters / minute of silicon tetrachloride using argon gas as a carrier is supplied from the nozzle 11.
Argon gas was ejected from the nozzle 12 at a flow rate of 1.5 liters / minute, oxygen was ejected from the nozzle 13 at 50 liters / minute, and LNG was ejected from the nozzle 14 at a rate of 30 liters / minute.

When a flame is actually generated by such a burner to produce glass fine particles, and the glass fine particles are deposited to produce a glass preform for an optical fiber,
The surface temperature of the base material can be raised up to 1000 ℃,
Good deposition was achieved as in the case of using hydrogen as the combustion gas. It was confirmed that the optical fiber made of this glass base material was as good as the ordinary optical fiber in its strand characteristics.

[0021]

As described above, according to the burner for producing glass of the present invention, LNG is used as a combustion gas in place of conventional hydrogen to stably form a high temperature flame and stabilize glass fine particles. Can be generated. As described above, since it is possible to generate glass fine particles comparable to the case where hydrogen is used by using LNG, it is possible to reduce the manufacturing cost of glass.

[Brief description of drawings]

FIG. 1 is a schematic partially enlarged perspective view of an embodiment of a glass forming burner according to the present invention.

FIG. 2 is a schematic front view of the burner of the same form.

FIG. 3 is a schematic sectional view of the burner of the same form.

FIG. 4 is a schematic perspective view of another form of burner.

[Explanation of symbols]

 11 Nozzle for Injecting Raw Material Gas 12 Nozzle for Injecting Argon Gas 13 Oxygen Ejecting Nozzle 14 LNG Ejecting Nozzle 21 Turbulent Flow Generating Material 22 Cap-shaped Attachment

Claims (3)

[Claims] 1. A first nozzle for ejecting a glass raw material gas, a second nozzle for ejecting oxygen, and a large cylindrical LNG surrounding the first and second nozzles. And a turbulent flow generating material provided in the vicinity of the ejection port of the third nozzle. 2. The glass producing apparatus according to claim 1, wherein the turbulent flow generating material is also used as a supporting material for holding and fixing the first and second nozzles in the third nozzle. For burners. 3. The burner for glass production according to claim 1, wherein the turbulent flow generating material is attached to a cap-shaped attachment body detachably attached to the tip of the third nozzle.