JP2003119034A - Manufacturing method and manufacturing apparatus for glass fine particle deposit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method which is capable of stably feeding clean air into a glass particulate deposit manufacturing apparatus, preventing the intrusion of impurity gas and decreasing the number of foreign matters intruding into a glass particulate deposit and an apparatus for the same. SOLUTION: This manufacturing method for the glass particulate deposit is a method of manufacturing the glass particulate deposit by using the glass particulate deposit manufacturing apparatus installed in a manufacturing building and depositing the glass particulates formed by a burner for synthesizing the glass particulates on a starting rod, in which the deposition of the glass particulates is performed while the clean air generated in a clean air generator for taking the air from an intake port opened outside the building into the building and cleaning the air is introduced into the apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a glass fine particle deposit by a vapor phase synthesis method, and more particularly to a method and an apparatus for producing a glass fine particle deposit which prevents an impurity gas from flowing into the production apparatus.

[0002]

2. Description of the Related Art In a method for producing a glass fine particle deposit by a vapor phase synthesis method such as an OVD method (external method), SiCl ₄ or GeCl ₄ as a glass raw material is supplied to a burner for synthesizing glass fine particles to burn flame. Glass fine particles such as SiO ₂ and GeO ₂ produced by the decomposition reaction are deposited on a rotating starting rod to produce a glass fine particle deposit body. In such a manufacturing method, when outside air containing dust or an impurity gas that corrodes a metal flows into the manufacturing apparatus for depositing glass particles, the metal inside the apparatus is corroded and the metal-based dust in the atmosphere inside the apparatus is dusted. When the number of the glass particles increases and the glass particles are deposited in such an atmosphere, metallic foreign matters are mixed in the glass particle deposit body. The optical fiber preform obtained by dehydrating and vitrifying such a glass particle deposit has abnormal points due to the above-mentioned bubbles and foreign matters, and frequently breaks during the fiber strength test after drawing.

Various methods have been studied for preventing foreign substances from adhering to the deposit particles during the deposition of the glass particles, and a method of introducing clean air into the reactor during the deposition of the glass particles has also been proposed. For example, Japanese Patent Laid-Open No. 5-1169
Japanese Patent Publication No. 79 discloses a method of spraying a clean gas flow over the entire length of a glass rod for a core to prevent foreign matters from adhering to a portion not hit by a flame when a glass particulate deposit is manufactured by the OVD method. There is.

[0004]

In the method of using such clean air, air having a reduced dust number is usually used by using a clean air generator having a high performance filter. The apparatus for producing a glass particle deposit is usually installed in the same building as a related apparatus such as a sintering device that heats a glass particle deposit in a post-process to a high temperature to form a transparent glass. In these devices, chlorine gas, SiC
_{l 4, GeCl 4, Cl 2} , and the gas to corrode metals such as SiF ₄ is frequently used, in the case where some trouble has occurred in some cases these special gas leaks, in their clean air generator Inhalation may damage the clean air generator, or it may mix in the clean air generator into the glass particulate deposit production equipment, corrode the metal material inside the equipment, and cause foreign matter to be generated. is there.

The present invention solves the above problems in the prior art, and even if there is a leak of a metal corrosive gas in the building in which the apparatus for producing glass particle deposits is installed,
An object of the present invention is to provide a method for producing a glass particle deposit body and an apparatus for the same, which can prevent the mixture of an impurity gas into the apparatus for producing a glass particle deposit body and reduce the number of foreign matters mixed in the glass particle deposit body. is there.

[0006]

The present invention provides the following methods (1) and (2) as means for solving the above problems. (1) Glass particulates are produced by supplying glass raw material to a burner for synthesizing glass particulates by using a glass particulate deposit manufacturing apparatus installed in a building and depositing glass particulates produced by flame hydrolysis on a rotating starting rod. In the method for producing a deposit, glass particles are deposited while introducing clean air generated by a clean air generator that takes in and purifies air from an intake opening opened to the outside of the building into the apparatus. And a method for producing a glass particulate deposit.

(2) A glass fine particle deposit manufacturing apparatus installed in a building, wherein a glass raw material is supplied to a burner for synthesizing glass fine particles to deposit glass fine particles produced by flame hydrolysis on a rotating starting rod. In a device for producing a glass particulate deposit, a clean air introducing pipe for introducing clean air generated by a clean air generator for taking in and purifying air from an intake opening opened to the outside of the building is connected. Characteristic glass particle deposit manufacturing apparatus.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The method and apparatus of the present invention are described below.
The case of manufacturing a glass particle deposit by the VD method will be described as an example with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing the outline of the apparatus configuration according to one embodiment of the present invention. The glass particulate deposit manufacturing apparatus (hereinafter, also simply referred to as a deposit manufacturing apparatus) 1 shown in FIG. An upper chimney 3 having an upper lid for loading and unloading the glass particle deposit body 15 and a glass particle deposit body 1
It is composed of a lower chimney 4 for reciprocating the movement 5.
A CA introduction pipe 9 for introducing clean air (CA) from a clean air (CA) generator 7 to the upper chimney 3 and the lower chimney 4.
Is installed. The CA introducing pipe 9 may be attached to either the upper chimney 3 or the lower chimney 4.

The CA generator 7 is an air purifying device equipped with a high-performance filter having a dust removing capacity according to the number of dusts in the required clean air, and filters the air taken in from the intake port 8 to remove the dusts. A device that removes the clean air and supplies it as clean air into the device through the connecting pipe 10 and the CA introducing pipe 9, and a device that is generally used for clean rooms can be used. CA generator 7 in this example
The intake port 8 is open outside the building in which the deposit manufacturing apparatus 1 is installed.

In this apparatus, starting rods prepared by welding dummy rods 14 to the upper and lower sides of a glass rod 13 respectively are held by a supporting rod 11 and are rotated by an elevating and lowering device 12 while reciprocating up and down, while surrounding burners. The glass fine particles synthesized in 5 are deposited to manufacture the glass fine particle deposit body 15. The burner 5 is a burner for synthesizing glass particles, which has a glass raw material ejection port such as SiCl ₄ , a flammable gas ejection port such as H ₂ , an auxiliary combustion gas ejection port such as O ₂ and an inert gas ejection port such as Ar. It can be preferably used.

Through the period in which the glass particles are deposited, clean air obtained by filtering the air sucked from the CA generator 7 from the building outside where the deposit manufacturing apparatus 1 is installed is supplied into the deposit manufacturing apparatus 1. To As a result, even if a corrosive gas generated during dehydration of glass raw material deposits or transparent glass vitrification leaks into the building where the deposit manufacturing apparatus 1 is installed due to some trouble, The gas is sucked into the CA generator 7 and does not corrode the CA generator 7 itself or the inside of the deposit body manufacturing apparatus 1, and the glass fine particles can be deposited in a clean environment.

[0012]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. (Example 1) A glass particulate deposit body was manufactured using the glass particulate deposit manufacturing apparatus 1 having the configuration shown in FIG.
Diameter 30mm with core / cladding, length 500m
A starting rod was manufactured by using a core rod (glass rod 13) of m and welding dummy rods 14 made of quartz glass on both sides. The starting rod was installed vertically while rotating at 40 rpm, and it was moved up and down at a speed of 200 mm / min.
A glass particle deposit 15 was prepared by sequentially depositing glass particles generated from the burner 5 for synthesizing glass particles while performing a traverse motion of mm. During the deposition of the glass particles, a clean air of 100 pieces / CF (about 0.0035 pieces / cm ³ ) of dust having a size of 0.3 μm or more from the CA generator 7 whose intake port 8 opens outside the building ( The number of dust is measured by the intensity of scattered light from particles using a laser particle counter), and the inside of the reaction vessel 2 is set to −20 Pa.
The negative pressure was maintained.

As the burners 5, three burners having a diameter of 30 mm are installed at intervals of 150 mm, and SiCl ₄ : ₄ SLM (standard liter / min) as a raw material and H ₂ for forming a flame are provided in each burner 5. 80 SLM and O ₂ : 40 SLM, and Ar: 2 as a seal gas
The operation of supplying the SLM and manufacturing the glass particulate deposit 15 of the target deposition weight (6.0 kg) was repeated.
During the continuous production, SiCl was used in the deposit production equipment 1 inside the building.
_{Although 4} gas leaked, various equipment parts such as the CA introduction pipe 9 did not corrode, and the operation could be continued. The produced glass fine particle deposit 15 was heated at a high temperature to be transparent vitrified, and then fiberized in order, but a screening test (a stretch rate of about 2% in the fiber longitudinal direction was performed on the preform before and after gas leakage. The frequency of disconnection in the fiber strength test for removing the low-strength portion by applying a load (1.9 kg for 1 second) does not change, and is 10 on average.
The frequency was once at 0 km.

(Comparative Example 1) The installation position of the CA generator 7 is
The glass fine particle deposit 15 was repeatedly manufactured in the same manner as in Example 1 except that the intake port 8 was opened in the same building as the deposit manufacturing apparatus 1 1 m above the lid of the apparatus. During the continuous production, S
As a result of the leakage of iCl ₄ gas, corrosion occurred in various equipment parts such as the CA introduction pipe 9. When the manufactured glass particle deposit 15 was heated at a high temperature to be transparent vitrified, and then fiberized, the preform before and after the gas leakage changed the disconnection frequency during the screening test, and the pre-gas leakage was 100 km before the gas leakage. The result was once, and 10 times at 100 km after gas leakage.

[0015]

EFFECTS OF THE INVENTION According to the present invention, it is possible to prevent the impurity gas from being mixed into the apparatus for producing glass particle deposits, and to reduce the number of foreign substances mixed in the object for glass particulate deposits. In the building where is installed, due to some trouble, chlorine gas, SiCl ₄ ,
Provided is a method for manufacturing a glass particle deposit body and an apparatus for the same, which does not increase the number of foreign substances mixed in the glass particle deposit body even when a corrosive gas such as GeCl ₄ , Cl ₂ , SiF ₄ leaks. It

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an outline of a device configuration according to one embodiment of the present invention.

Claims (2)

[Claims] 1. A glass fine particle deposit manufacturing apparatus installed in a building is used to supply a glass raw material to a burner for synthesizing glass fine particles to deposit glass fine particles produced by flame hydrolysis on a rotating starting rod. In the method for producing a glass particle deposit, the glass particles are deposited while introducing clean air generated by a clean air generator that takes in and purifies air from an intake opening opened outside the building into the apparatus. A method for producing a glass particulate deposit, comprising: 2. An apparatus for producing a glass particle deposit body installed in a building, wherein a glass raw material is supplied to a burner for synthesizing glass particles, and glass particles produced by flame hydrolysis are deposited on a rotating starting rod. In an apparatus for producing a glass particulate deposit, a clean air introducing pipe for introducing clean air generated by a clean air generator for taking in and purifying air from an intake opening opened to the outside of the building is connected An apparatus for manufacturing glass particulate deposits.