JP2003183035A - Manufacturing device for glass fine particle deposition body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing device for a glass fine particle deposition body capable of shielding heat without disturbing gas flow in a reaction vessel, and capable of reducing heat load to the reaction vessel, and also capable of effectively exhausting floating soot, capable of preventing generation of bubbles at the time of vitrification. <P>SOLUTION: The manufacturing device provided with the reaction vessel, in which a starting material 2 is placed horizontally and freely rotatably, a burner 3 for deposition is reciprocated along and parallel to the starting material 2, is constituted such that the reaction vessel 1 sucks air from a whole bottom surface, and exhausts it from its upper part, and heat shielding plates 4 are provided detachably along the starting material 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a glass particulate deposit used for producing a glass particulate deposit as a raw material for an optical fiber.

[0002]

2. Description of the Related Art A glass particle deposit for optical fibers (hereinafter referred to simply as a deposit) is, for example, an external vapor deposition method (O).
By the VD method), glass raw materials such as tetrachlorosilane are supplied and hydrolyzed into the flame of the burner reciprocating along the rotating starting member, and the resulting glass particles (soot) are generated on the starting member. It is manufactured by depositing on. At this time, the fine glass particles (soot) floating in the reaction vessel without being deposited on the starting member and the hydrogen chloride gas produced as a byproduct,
It is discharged from the system through an exhaust pipe attached to the reaction vessel.

[0003]

Conventionally, when the air flow in the reaction vessel is rectified without a circulating flow, the amount of glass particles adhering to the inner wall surface of the reaction vessel is reduced, and the adhered matter is peeled off and deposited on the deposit. It is said that bubbles generated in the product due to falling can be reduced. In Japanese Unexamined Patent Application Publication No. 13-019437, the structure of the reaction vessel is configured so that a rectified air flow is introduced from the bottom and discharged from the top, so that the rectified state is more effectively maintained by the upward flow generated by the reaction heat. It is said that the generation of bubbles can be suppressed.

On the other hand, if the number of burners is increased or the amount of combustion gas supplied to the burners is increased in order to increase the production speed, the temperature of the reaction vessel rises, causing a problem that the reaction vessel is deformed or damaged. This heat is mainly transferred from the deposition surface to the reaction vessel by radiation, so in order to lower the temperature of the reaction vessel, it is necessary to increase the distance between the wall of the reaction vessel (hereinafter referred to as the vessel wall) and the deposition surface. Occurs. As a result, the cross-sectional area of the reaction vessel increases and a large amount of gas needs to be introduced into and discharged from the reaction vessel in order to maintain the rectified state.

Since the gas in the reaction vessel contains hydrogen chloride gas produced by the reaction, the exhaust gas needs to be discharged out of the system after the cleaning treatment, and the increase in the exhaust gas treatment amount is a factor of cost increase. Become. Further, in order to reduce the heat load on the reaction vessel, it is effective to install a heat shield plate. Japanese Patent No. 2888448 discloses a device for fixing a heat shield plate loosely with respect to a reaction vessel. However, this device has a problem that stagnation occurs between the heat shield plate and the reaction container, soot is likely to adhere during this period, and this easily causes bubbles in the product. Further, in order to prevent stagnation, it is necessary to separate the heat shield plate from the reaction container, but in this case, there is a problem that it becomes an obstacle when the manufactured glass particle deposit is taken out from the reaction container.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and it is possible to shield heat without disturbing the air flow in the reaction vessel and reduce the heat load on the reaction vessel. It is intended to provide an apparatus for manufacturing a deposited body, which can efficiently discharge floating soot and can prevent generation of bubbles and the like during vitrification.

[0007]

That is, in the apparatus for producing a deposit according to the present invention, a burner is reciprocally moved in parallel to a starting member arranged horizontally and rotatably along the starting member so that fine glass particles are generated. An apparatus for spraying and producing a deposit in a reaction container is characterized in that the reaction container is configured so that air is taken in from the entire bottom surface and exhausted from the upper part and has a removable heat shield plate. Removable means that the heat shield plate can be moved to a place where it does not interfere with the stack when the stack is taken out. In the manufacturing apparatus of the present invention, a heat shield plate is disposed vertically between the inner wall of the reaction vessel and the deposition surface, and further, a moving mechanism for moving the heat shield plate in parallel along the starting member and a heat shield plate. It is preferable to provide an attaching / detaching mechanism capable of removing the plate. The heat shield plate is preferably made of quartz glass or a double structure of quartz glass and infrared absorbing glass.

Further, it is preferable that the manufacturing apparatus of the present invention is provided with a housing portion for drawing out and housing the heat shield plate. It is preferable that the exhaust port is provided over a length not less than the moving range of the burner that reciprocates along the starting member, and that the upper part of the reaction vessel is formed so that the flow path of the air flow becomes gradually narrower toward the exhaust port. . The method for manufacturing a deposit according to the present invention is manufactured using the manufacturing apparatus having the above configuration.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a model of an apparatus for producing a deposit according to the present invention.
The starting member (deposit) 2 is arranged horizontally and rotatably. A deposition burner 3 is provided below the starting member (deposit) 2.
The heat shield plate 4 is disposed between the deposition surface of the deposition burner 3 on the deposit body 2 and the inner wall of the reaction vessel 1 in parallel and vertically along the starting member. An inlet 5 for airflow is provided at the bottom of the reaction vessel 1, and an exhaust port 6 for exhaust gas is provided at the top of the reaction vessel 1. In addition to reducing the heat load on the reaction vessel, the heat shield plate 4 also has a rectifying function of rectifying the air flow sucked from the intake port 5.

The production apparatus of the present invention is an apparatus for producing a deposit by spraying fine glass particles by reciprocally moving the deposition burner in parallel along a horizontally arranged starting member.
In order to carry out stable deposition by rectifying the air flow in the reaction vessel, it is configured so that air is taken in from the entire bottom surface of the reaction vessel and discharged from the top. In addition, intake is performed from a large number of small holes provided over almost the entire area of the bottom of the reaction vessel, for example.

It is desirable that the exhaust port provided in the upper portion of the reaction vessel has a length equal to or longer than the region of the flame of the deposition burner that reciprocates along the starting member. Further, as shown in FIG. 1, it is preferable that the upper portion of the reaction container has a structure in which the flow path of the air flow is gradually narrowed toward the exhaust port so that the air flow is not disturbed and the speed of the air flow gradually increases. The effect of suppressing the attachment of soot to the vessel wall of the reaction container is obtained. The air flow in the reaction vessel is exhausted from the exhaust port without disturbing the rectified state.

In order to reduce the heat load received by the reaction vessel, that is, in order to suppress the radiant heat received by the vessel wall,
A heat shield is installed between the deposition surface and the vessel wall. The heat shield plate is installed in the rectified air flow, and the distance between the heat shield plate and the vessel wall is set to 20% or more of the distance between the deposition surface and the vessel wall so that the air flow does not cause stagnation. To do. If the distance between the heat shield plate and the deposition surface is too close to the deposition surface, soot generated from the deposition surface easily adheres to the heat shield plate, so that the distance between the deposition surface and the vessel wall is 40%. It is desirable to set it to be at least%.

The heat shield plate is preferably made of a material having a light-transmitting property and heat resistance so that the deposition surface can be observed.
Examples include quartz glass. It is more effective to use a double structure in which infrared absorbing glass is arranged on the side of the quartz glass wall. The heat shield plate is provided with columns at both ends of the heat shield plate 4,
It is good to have a structure that stands upright on the bottom of the reaction vessel,
It is installed vertically along the air flow from below and parallel to the starting member. For example, as shown in FIGS. 2A and 2B, a slide guide 7 provided at the bottom of the reaction container
It is installed by housing the legs 9 of the pillar 8. When taking out the stack, the plurality of heat shield plates 4 are sequentially drawn into and housed in the housing unit 10 so as not to disturb the work. The heat may be shielded by moving one heat shield plate 4 in accordance with the movement of the deposition burner.

[0014]

Example 1 Using the deposit manufacturing apparatus shown in FIG. 1, a quartz glass heat shield plate was installed parallel and vertically along a starting member. The installation positions of the heat shield plates at this time are positions where the distance between the device wall and the heat shield plate and the distance between the heat shield plate and the starting member are 800 mm and 800 mm, respectively.
As a starting member, a quartz glass rod with an outer diameter of 50 mmφ and a length of 4000 mm adjusted for the core was attached to the gripping mechanism of the device, 20 burners were attached, and each burner was made of SiC.
l ₄ : 30 g / min, O ₂ : 20 liters / min, H ₂ : 60
By supplying liter / min, glass fine particles generated by the flame hydrolysis reaction were attached and deposited on the core starting member to obtain a deposit having an outer diameter of 400 mmφ. During the deposition, the deposition state could be observed through a quartz glass heat shield plate. Further, the temperature of the device remained below 250 ° C., and the coating of the device did not discolor. When the obtained deposit was sintered and made into a transparent glass, no bubbles were generated.

(Example 2) A deposit was produced in the same manner as in Example 1 except that a heat shield plate having a double structure of quartz glass and infrared absorbing glass was used. During the deposition, the deposition state could be observed through the heat shield plate. The temperature of the device remained below 220 ° C., and the coating of the device did not discolor. When the obtained deposit was sintered and made into a transparent glass, no bubbles were generated.

Comparative Example 1 A deposit was manufactured in the same manner as in Example 1 except that the heat shield plate was not used. During the deposition, the temperature of the device became 350 ° C. or higher, and since the heat resistant temperature of the coating exceeded 280 ° C., the coating discolored and came off. When this deposit was sintered and made into a transparent glass, a large amount of bubbles were generated in the glass base material.

[0017]

The manufacturing apparatus of the present invention having the above structure is
Glass particles (soot) that have not adhered during glass particle deposition
Since the foreign matter that has peeled off or peeled off is not mixed in the product, there is no bubble or impurity contamination in the product. Also, by providing the heat shield plate, the heat load on the reaction vessel can be greatly reduced, the distance between the vessel wall and the deposition surface can be shortened, the apparatus can be downsized, and the life of the apparatus can be shortened. It can be extended significantly.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a model of a deposition body manufacturing apparatus of the present invention.

FIG. 2A is a front view showing a heat shield plate, and FIG.
FIG. 3 is a plan view schematically showing a slide guide that guides the legs of the heat shield plate.

[Explanation of symbols]

1. Reaction vessel 2. Starting material (deposit) 3. Deposition burner 4. Heat shield plate 5. Intake 6. exhaust port 7. Slide guide 8. Pillar 9. leg 10. Housing

Claims (11)

[Claims] 1. An apparatus for producing a glass particle deposit in a reaction vessel by spraying glass particles onto a horizontally and rotatably arranged starting member by reciprocating a burner in parallel along the starting member. An apparatus for producing glass particulate deposits, characterized in that the reaction container is constructed so as to intake air from the entire bottom surface and exhaust air from the top, and has a removable heat shield plate. 2. The apparatus for producing a glass fine particle deposit according to claim 1, wherein the movable heat shield plate is disposed between the inner wall of the reaction container and the deposition surface. 3. The apparatus for producing a glass particle deposit according to claim 1, wherein the heat shield plate is arranged vertically. 4. The apparatus for producing a glass particulate deposit body according to claim 1, further comprising a housing portion for drawing out and housing the heat shield plate. 5. The apparatus for producing a glass particulate deposit body according to claim 1, further comprising an attachment / detachment mechanism capable of detaching the heat shield plate. 6. The apparatus for producing a glass particle deposit according to claim 1, further comprising a moving mechanism that moves the heat shield plate in parallel along the starting member. 7. The heat shield plate is made of quartz glass.
7. The manufacturing apparatus for a glass particle deposit according to any one of 1 to 6. 8. The apparatus for producing a glass fine particle deposit according to claim 1, wherein the heat shield plate has a double structure of quartz glass and infrared absorbing glass. 9. The apparatus for producing a glass fine particle deposit according to claim 1, wherein the exhaust port is provided over a length not less than a moving range of the burner that reciprocates along the starting member. 10. The apparatus for producing a glass fine particle deposit according to claim 1, wherein an upper part of the reaction vessel is formed so that a flow path of the air flow becomes gradually narrower toward the exhaust port. 11. A method for producing a glass fine particle deposit, which is produced using the apparatus for producing a glass fine particle deposit according to any one of claims 1 to 10.