JP2003340265A - Method and apparatus for vaporizing liquid raw material, and apparatus for producing glass base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a high quality glass base material by controlling the change in the amount of a liquid raw material to be supplied to a burner in the vaporization of the liquid raw material by a bubbling method. <P>SOLUTION: In an apparatus for vaporizing the liquid raw material by introducing carrier gas with its flow rate controlled into the raw material, a lower part heater 2 for heating a liquid phase part and an upper part heater 3 for heating a gas phase part are different from each other. In this way, the temperature increase in gas of low specific heat can be controlled so that the change in the amount of raw material gas to be supplied to the apparatus which uses the raw material gas can be controlled. By supplying the liquid raw material continuously from a raw material supply system 10 on the basis of the level detection results of a level sensor 9, the temperature of liquid and gas in a container 1 can be controlled surely, so that the amount of the raw material to be supplied can be stabilized. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid raw material vaporizer, a liquid raw material vaporization method, and a glass base material manufacturing apparatus using the liquid raw material vaporizer, and more specifically to a liquid raw material such as a glass raw material. The present invention relates to a liquid raw material vaporizing apparatus and method adapted to be vaporized and used for producing a glass preform used for an optical fiber and the like, and a glass preform producing apparatus having the liquid raw material vaporizer.

[0002]

2. Description of the Related Art As a method of manufacturing a cylindrical glass preform used for manufacturing optical fibers, for example, the VAD method (vapor phase axis method) is known. FIG. 6 is a diagram for explaining a method for manufacturing a porous glass base material by the VAD method.
Reference numeral 30 is a reactor vessel, 31 is a suspender (seed rod mounting means), 32 is a seed rod, 33 is a glass porous base material, 34 is a core burner (first burner), and 35 (second burner) is a clad burner. is there. In the configuration shown in FIG. 6, the core burner 34 for the core is used as the burner for producing the glass fine particles.
And a clad burner 35 for clad, the core burner 34 forms a core portion of the optical fiber, and the clad burner 35 forms a clad portion that becomes a clad of the optical fiber.

[0003] VAD method, glass raw material gas by chloride such as SiCl _4, the dopant source gas such as GeCl _4, is ejected fuel gas such as H _2, and a combustion supporting gas such as O ₂ from the burner, the burner flame By hydrolyzing and oxidizing in the base material, a base material is formed by SiO ₂ glass fine particles. At this time, as is well known, the porous glass base material used for manufacturing the optical fiber has a refractive index n2 of the cladding.
On the other hand, since it is necessary to increase the refractive index n1 of the core within a predetermined range, for example, GeCl ₄ is supplied as a raw material to the core burner 34, and G generated by the oxidation reaction in the flame is
A method of doping SiO ₂ with eO ₂ is used.

The glass raw material gas ejected from each of the burners 34 and 35 is deposited on the rotating seed rod 32, and the seed rod 32 is gradually pulled upward to grow the raw material by fine glass particles. A porous glass base material 33 is obtained. Porous glass base material 33 obtained after this
After being dehydrated, it is heated and sintered in a high temperature atmosphere to form a transparent glass.

As a method of supplying the raw material gas to each of the burners 34 and 35 as described above, a bubbling method and a raw material direct feeding method are known. In the bubbling method, a metal or glass container containing a glass liquid raw material such as SiCl ₄ and a liquid raw material for a dopant such as GeCl ₄ is separately prepared, and a gas flow controller such as MFC (mass flow controller) is used. Flow rate controlled N ₂ gas or A
A carrier gas consisting of an inert gas such as r gas is forcibly ventilated into each container, and the raw material is vaporized by bubbling. Each vaporized source gas is vaporized and diffused in the carrier gas, and is sent to the core burner 34 and the clad burner 35 as a mixed gas of the source gas and the carrier gas. Here, as described above, glass raw material gas such as SiCl ₄ is supplied to the clad burner 35 together with reactive gas such as H ₂ and O _2, and glass such as SiCl ₄ is supplied to the core burner 34. The raw material gas and a dopant raw material gas such as GeCl ₄ are further mixed and fed together with a reactive gas such as H 2 and O ₂ .

On the other hand, in the direct feed method, a vaporization vessel containing a silicon compound such as SiCl ₄ is prepared, heating steam is introduced into the vaporization vessel via an electric heating tube, and indirect heating by latent heat of condensation of the heating steam is performed. Is used to vaporize a silicon compound such as SiCl ₄ and send the gas to the core burner 34 and the clad burner 35. At this time, for the core burner 34, a doping material such as GeCl ₄ is similarly vaporized by heating steam and mixed with the SiCl ₄ gas for the core at a predetermined ratio through a flow rate controller, and the mixed gas is fed to the core burner 34. Send air.

That is, in the raw material direct delivery method, the carrier gas is not used, and the raw material is heated at a temperature above the boiling point to be vaporized, and then the flow rate is controlled by the mass flow controller. On the other hand, in the bubbling method, the flow rate of a carrier gas is controlled in advance by a mass flow controller, and a bubbler container (raw material gas vaporization tank)
By bubbling inside, a constant flow rate of the raw material is sent out by an amount corresponding to the vapor pressure with respect to the carrier gas.

The direct feed method has the advantage of canceling atmospheric pressure fluctuations and temperature fluctuations in the bubbler container as described above, and is ideal in principle. However, the glass main raw material made of a silicon compound such as SiCl ₄ has a large gas flow rate and can be stably supplied to the burner, but the gas used as a dopant such as GeCl ₄ has a small flow rate, and therefore is directly fed from the raw material. Even if the method is used, there is a problem that stable supply is difficult.

That is, in order to supply a small amount of raw material by the direct raw material feeding method, a mass flow controller for controlling a low flow rate is required. However, the accuracy of the flow rate control of the mass flow controller becomes a problem, and it is difficult to stabilize a small supply amount of the dopant raw material. In addition, the boiling point of GeCl ₄ used as a dopant material is 84.0 ° C.
It has a high boiling point with respect to the boiling point of iCl ₄ of 57.6 ° C.
That is, since the heating temperature is relatively high in order to vaporize the high boiling point raw material, it is necessary to ensure the thermal stability of the raw material supply system including the mass flow controller, and also in terms of equipment cost and maintenance. There's a problem.

Further, when the gas is supplied at a low flow rate like the dopant raw material, if the temperature of the pipe between the raw material supply device and the burner changes, the effect on the actual flow rate fluctuation is inevitably large. When the raw material gas has a high temperature and a low flow rate, when mixing with other gas on the upstream side of the burner, concentration unevenness occurs at the mixing point due to convection, etc., and the flow rate of the raw material gas supplied to the burner fluctuates. Occurs.

On the other hand, in the bubbling method, there is an inherent problem that the actual flow rate of the raw material gas changes with the fluctuation of the gas phase pressure of the bubbler container. In order to solve such a problem, for example, in the bubbling method disclosed in JP-A-8-283026, the pressure inside the bubbler container is 0.098 to 0.09 in gauge pressure.
There is disclosed a technique for reducing the influence of the vapor phase pressure fluctuation as described above by raising the pressure to about 196 MPa (1-2 kg / cm ³ ).

By using the method described in the above publication, the disturbance due to the fluctuation of the gas phase pressure can be canceled. However, the fluctuation of the actual flow rate of the raw material due to the fluctuation of the gas phase temperature in the bubbler container has not been solved, and it has been difficult to stably supply the raw material with time. So far, no prior art has been disclosed in which such fluctuations in the gas phase temperature are suppressed.

Although a liquid phase and a gas phase coexist in the bubbler container, this point is not taken into consideration in the conventional technique even though the liquid and gas have different heat capacities. Making adjustments. Generally, the temperature control of a bubbler container needs to compensate for the latent heat of vaporization of the raw material due to bubbling.Therefore, an indirect heating method such as a constant temperature bath cannot follow the temperature change due to the latent heat at the start of bubbling. This causes periodic temperature fluctuations. Therefore,
It is common to use a method of directly heating the circumference of the bubbler container using a mantle heater.

However, if the entire bubbler container is heated by one mantle heater to adjust the temperature, the gas is easily heated, and the temperature of the gas largely fluctuates, resulting in a volume change. Normally, an element called a condenser that is controlled at a temperature lower than that of the bubbler container is arranged downstream of the gas flow path from the bubbler container, and the vapor pressure is controlled to be constant here, but it is supplied from the bubbler container. It cannot cope with the volume change of gas. Therefore, the flow rate of the source gas supplied to the burner fluctuates due to the volume change caused by the temperature change of the gas phase.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and suppresses the fluctuation of the raw material supply amount to the burner in the vaporization of the liquid raw material by the bubbling method, thereby achieving high quality. It is an object of the present invention to provide a liquid raw material vaporization method, a liquid raw material vaporization apparatus, and a glass base material production apparatus using the vaporization apparatus, which are capable of producing a glass base material.

[0016]

A liquid source vaporizer of the present invention includes a container for storing a liquid source, a flow rate control means for controlling a unit flow rate of carrier gas, and a carrier gas whose flow rate is controlled by the flow rate control means. A means for introducing the liquid raw material housed in the container, a heater for heating the container, a temperature control means for controlling the temperature of the heater, and a mixed gas of the liquid raw material vaporized gas and a carrier gas for cooling. A gas cooling means for controlling the temperature to a predetermined temperature, the temperature of the heater is controlled to a predetermined temperature by the temperature control means, by passing the carrier gas as bubbles in the liquid, the liquid raw material into the carrier gas In a liquid source vaporizer that is vaporized and diffused to generate a mixed gas of a carrier gas and a gas obtained by vaporizing a liquid source, a heater is a liquid phase in which the liquid source is stored. And a heater for vapor phase arranged corresponding to the vapor phase portion above the container, and the temperature control means includes a heater for liquid phase and a heater for vapor phase. Are individually controlled in temperature.

In the liquid raw material vaporization method of the present invention, a container containing the liquid raw material is heated and controlled to a predetermined temperature, and a carrier gas whose unit flow rate is controlled is introduced into the container and passed as bubbles in the liquid. By this, the liquid raw material is vaporized and diffused into the carrier gas to generate a mixed gas of the carrier gas and the gas in which the liquid raw material is vaporized, and the generated mixed gas is cooled and controlled to a predetermined temperature. In the method, the heater comprises a liquid-phase heater arranged corresponding to a liquid-phase portion in which a liquid raw material is stored, and a vapor-phase heater arranged corresponding to a vapor-phase portion above the container. Then
The liquid phase heater and the vapor phase heater are individually temperature-controlled.

The apparatus for producing a glass base material of the present invention comprises a liquid raw material vaporizer for individually vaporizing and diffusing a glass liquid raw material and a dopant liquid material into a carrier gas to form a mixed gas, and a mixture cooled to a predetermined temperature. It has a burner for introducing a gas together with a reactive gas of oxygen and hydrogen, and a seed rod mounting means for mounting a seed rod for depositing glass fine particles synthesized by the oxyhydrogen reaction in the burner and allowing the seed rod to move up and down. A device for producing a glass preform for producing a glass preform by pulling up the seed rod while depositing the glass fine particles on the seed rod, the liquid raw material vaporizing device vaporizing at least a liquid raw material for a dopant as described above. The liquid raw material vaporizer according to the present invention is used.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a view showing an embodiment of a bubbling device according to the present invention, in which 1 is a container, 2a is a lower heater, 2b is an upper heater,
3 is a heat insulating material, 4 is a metal plate for heat conduction, 5 is a first power supply system, 6 is a first temperature measurement control system, 7 is a second power supply system, and 8 is a second temperature measurement control system. , 9 are liquid level sensors, 10
Is a raw material supply system, 11 is a raw material supply pipe from the raw material supply system to the container, 12 is a heater for heating the raw material supply pipe, 13
Is a pipe for introducing a carrier gas into the container, 14 is a pipe for supplying gas from the container to the glass synthesizing device, 15 is a condenser as a gas cooling means, 16 is a circulating water supply pipe for the condenser, and 17 is a condenser to the temperature controller. A circulating water discharge pipe 18 is a liquid raw material, and 19 is an MFC (mass flow controller) which is a flow rate control means.

Using the bubbling device shown in FIG. 1, a container 1
GeCl ₄ is sealed in and the carrier gas (Ar) is introduced through the carrier gas introduction pipe 13 inserted into the container 1 to perform bubbling. The container 1 has a cylindrical shape with an inner diameter of 350 mm and a height of 400 mm, and in order to keep the temperature inside the container 1 constant, the heating temperature is adjusted using a mantle heater. In this embodiment, a lower heater 2a for heating the liquid phase portion and an upper heater 2b for heating the gas phase portion.
Are respectively configured with different mantle heaters, temperature measurement control systems 6 and 8 as temperature control means are individually installed, and each power supply system 5 and 7 is based on a control signal of each temperature measurement control system 6 and 8. Power is supplied from. In this way, the lower heater 2a and the upper heater 2b are individually and individually temperature-controlled.

Further, in this embodiment, for heat conduction, heat is conducted from the wall surface of the container 1 to the gas phase region above the liquid surface of the liquid raw material so that the gas in the gas phase can be efficiently heated. The metal plate 4 was installed. Further, a condenser 15 is installed in the gas supply pipe 14 from the container 1 to the glass synthesizing device, and the circulating water whose temperature is controlled by a temperature controller (not shown) is supplied to the pipe 1.
6, the circulating water is returned to the temperature controller by an exhaust pipe 17.

Further, in this embodiment, a liquid level sensor 9 and a raw material replenishing system 10 for replenishing the raw material into the container 1 based on the liquid level detection signal from the liquid level sensor 9 are provided. The liquid level sensor 9 is adapted to detect the liquid level height in the container 1. The liquid level sensor 9 transfers a detection signal based on the liquid level detection result by the liquid level sensor 9 to the raw material replenishing system 10 and the raw material replenishing system 10
On the basis of the input detection signal, the material is continuously replenished so that the liquid surface of the liquid material in the container 1 is always maintained at a predetermined position. A heater 12 is provided in a raw material supply pipe 11 from the raw material supply system 10 to the container 1 to control the raw material temperature in the raw material supply passage. The liquid level sensor 9
The type is not limited to that type, and a float type or an ultrasonic type can be appropriately used.

Using the above bubbling device, the above V
A glass porous base material was manufactured by the AD method. The above
The bling device is a bubbling device for relatively low flow rate dopants.
The bubbler container for glass raw materials has a conventional structure.
I used the one that I made. GeC for the bubbler container for dopant
l_FourSupplying liquid raw materials for dopants, and also glass raw materials
For the bubbler container, use SiCl_FourOf glass liquid raw materials
I paid. And the gas by the mass flow controller 19
The inert gas Ar whose flow rate is controlled by the flow rate controller
Bubbling raw materials by forcibly ventilating each container
Was vaporized. SiC for the clad burner 35
l_FourReaction gas H₂, O ₂With air
However, for the core burner 34, SiCl_FourGlass raw material
Gas and GeCl_FourFurther mixing with the dopant source gas of
Then reaction gas H₂, O₂With the air.

Thus, the core made of SiO ₂ containing GeO ₂ as a dopant and the SiO ₂ containing no dopant
A glass porous preform (soot) for an optical fiber having a clad made of was prepared.

The carrier gas flow rate of the bubbling device for the dopant was 107 cm ³ / min, and the lower heater 2a was used.
Both the upper heater 2b and the upper heater 2b were set to 40 ° C., and the raw material was vaporized by bubbling. Also capacitor 1
It was cooled so that the temperature of the gas became 30 ° C. by the circulating water circulated in No. 5. This kept the vapor pressure of the raw material gas in the gas constant.

FIG. 2 is a diagram showing the refractive index distribution in the radial direction of the transparent glass base material which is made transparent by dehydration sintering of the glass base material manufactured according to this embodiment. The glass porous preform produced using the bubbling apparatus according to this example as described above was heat-treated in a dehydration sintering furnace to be a transparent vitrification. As a result of measuring the refractive index distribution of the obtained transparent glass base material using a preform analyzer, the refractive index distribution as shown in FIG. 2 was obtained. As shown in FIG. 2, the difference Δn (core Δn) between the refractive index of the clad made by the second burner 35 and the refractive index of the core made by the first burner 34 is 0.45% of the refractive index of the clad. Met.

FIG. 3 is a diagram showing the refractive index distribution in the longitudinal direction of the transparent glass preform which is made transparent by dehydration sintering of the glass preform manufactured according to this example. Using the refractive index difference Δn between the core and the clad as described above as a parameter,
As a result of investigating the stability of the refractive index distribution in the longitudinal direction of the transparent glass base material, as shown in FIG. 3, the fluctuation range of Δn is 0.00
It was confirmed to be extremely stable at 6%.

Therefore, as in the present embodiment, the liquid and the gas in the bubbling device are heated by different heaters and the respective heaters are controlled to suppress the temperature rise of the gas having a relatively small specific heat. It becomes possible to suppress the fluctuation of the raw material supply amount to the burner. In addition, by continuously replenishing the raw materials during bubbling to keep the height of the liquid surface constant, it is possible to more reliably control the temperature of the liquid and gas in the container. Can be stabilized.

The heater structure of the bubbling apparatus according to the present invention can be applied not only to the bubbler container for the dopant raw material having a small flow rate but also to the bubbler container for the glass raw material having a large flow rate.

(Comparative Example) FIG. 4 is a view for explaining a comparative example for the bubbling device according to the present invention.
2 is a heater for heating which is commonly used regardless of liquid phase or vapor phase, 21 is a temperature measurement control system of the heater, 22 is an electric power supply system, and other parts having the same functions as in FIG. The same reference numeral as 1 is attached.

In this comparative example, bubbling is performed by using a common mantle heater (heating heater 2), a temperature measurement control system 21, and a power supply system 22 without providing separate upper and lower heaters as in the above embodiment. Heat the device. The liquid raw material for dopant was vaporized by such a bubbling device, and was fed to the same VAD device as in Example 1 to prepare a glass porous base material.

FIG. 5 is a diagram showing the refractive index distribution in the longitudinal direction of a transparent glass preform which is made transparent by dehydration sintering of the glass preform produced in this comparative example. As a result of measuring the refractive index distribution in the longitudinal direction of the transparent glass base material produced using the bubbling device according to the comparative example, as shown in FIG. 5, Δn is periodically increased with a fluctuation range of about 0.01%. It has fluctuated.

[0033]

As is apparent from the above description, according to the present invention, the liquid and the gas in the bubbling device are heated by different heaters, and the heaters are controlled so that the gas having a small specific heat can be obtained. It is possible to suppress the temperature rise of the above, and it is possible to suppress the fluctuation of the raw material supply amount to the burner. In addition, by continuously replenishing the raw materials during bubbling to keep the height of the liquid surface constant, it is possible to more reliably control the temperature of the liquid and gas in the container. Can be stabilized.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a bubbling device according to the present invention.

FIG. 2 is a diagram showing a refractive index distribution in a radial direction of a transparent glass base material which is made transparent by dehydration sintering of the glass base material manufactured according to this example.

FIG. 3 is a view showing a refractive index distribution in a longitudinal direction of a transparent glass base material which is made transparent by dehydration sintering of the glass base material manufactured according to this example.

FIG. 4 is a diagram for explaining a comparative example with respect to the bubbling device according to the present invention.

FIG. 5 is a view showing a refractive index distribution in a longitudinal direction of a transparent glass base material which is made transparent by dehydration sintering of the glass base material manufactured by this comparative example.

FIG. 6 is a diagram for explaining a method for manufacturing a porous glass preform by the VAD method.

[Explanation of Codes] 1 ... Container, 2 ... Heating heater, 2a ... Lower heating heater,
2b ... Top heater, 3 ... Insulation material, 4 ... Heat conduction metal plate, 5 ... First power supply system, 6 ... First temperature measurement control system, 7 ... Second power supply system, 8 ... Second 2 temperature measurement control system, 9 ... liquid level sensor, 10 ... raw material supply system, 11 ... raw material supply pipe, 12 ... heater, 13 ... carrier gas introduction pipe, 14 ... gas supply pipe, 15 ... condenser, 16 ...
Circulating water supply pipe, 17 ... Circulating water discharge pipe, 18 ... Liquid raw material, 19 ... MFC (mass flow controller) 20 ...
Heating heater, 21 ... Temperature measurement control system, 22 ... Power supply system, 34 ... First burner, 35 ... Second burner.

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[Procedure amendment]

[Submission date] May 31, 2002 (2002.5.3)
1)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Miki Nakaura             Kiyohara Industrial Park 18-5 Kiyohara, Utsunomiya City, Tochigi Prefecture             Harazumi Electric Co., Ltd. (72) Inventor, Miki Yagi             Kiyohara Industrial Park 18-5 Kiyohara, Utsunomiya City, Tochigi Prefecture             Harazumi Electric Co., Ltd. F-term (reference) 4G014 AH01 AH04                 4G068 DA10 DB03 DB26 DC04 DD01

Claims (7)

[Claims] 1. A container for storing a liquid raw material, a flow rate control means for controlling a unit flow rate of a carrier gas, and a means for introducing a carrier gas whose flow rate is controlled by the flow rate control means into the liquid raw material stored in the container. A heater for heating the container, temperature control means for controlling the temperature of the heater, and gas cooling for cooling the mixed gas of the gas in which the liquid raw material is vaporized and the carrier gas to a predetermined temperature. Means for controlling the temperature of the heater to a predetermined temperature by the temperature control means, and passing the carrier gas as bubbles in the liquid, thereby vaporizing and diffusing the liquid raw material into the carrier gas. A liquid raw material vaporizer configured to generate a mixed gas of the carrier gas and a gas obtained by vaporizing the liquid raw material, wherein the heater is the liquid raw material. Is composed of a liquid-phase heater arranged corresponding to the liquid-phase portion in which is stored, and a vapor-phase heater arranged corresponding to the vapor-phase portion of the upper part of the container, and the temperature control means comprises: A liquid raw material vaporizer characterized in that the temperature of each of the liquid phase heater and the vapor phase heater is individually controlled. 2. A liquid level detection sensor for detecting the liquid level of the liquid raw material housed in the container, and a liquid level level in the container kept constant based on a liquid level detection result by the liquid level detection sensor. The liquid raw material vaporizer according to claim 1, further comprising: a means for supplying a liquid raw material. 3. A heat conducting metal plate for efficiently conducting the heat generated by the heater to the gas in the vapor phase portion is disposed in a space corresponding to the vapor phase portion inside the container. The liquid raw material vaporizer according to claim 1 or 2. 4. The liquid raw material is controlled by heating a container containing the liquid raw material to a predetermined temperature, introducing a carrier gas having a controlled unit flow rate into the container, and passing the carrier gas as bubbles in the liquid. A method for vaporizing a liquid raw material, wherein a mixed gas of the carrier gas and a gas obtained by vaporizing the liquid raw material is generated by vaporizing and diffusing into the carrier gas, and the generated mixed gas is cooled and controlled to a predetermined temperature. The heater is composed of a liquid-phase heater arranged corresponding to a liquid-phase portion in which the liquid raw material is stored, and a vapor-phase heater arranged corresponding to a vapor-phase portion above the container. The temperature of the liquid phase heater and the temperature of the gas phase heater are individually controlled. 5. The liquid level of the liquid raw material housed in the container is detected by a liquid level detection sensor, and the liquid level in the container is kept constant based on the liquid level detection result of the liquid level detection sensor. The liquid raw material vaporization method according to claim 4, wherein a liquid raw material is supplied. 6. A heat conducting metal plate for efficiently conducting heat generated by the heater to a gas in the vapor phase portion, in a space corresponding to the vapor phase portion inside the container. 6. The liquid raw material vaporization method according to claim 4 or 5. 7. A liquid raw material vaporizer for individually vaporizing and diffusing a glass liquid raw material and a dopant liquid material into a carrier gas to form a mixed gas, and the reactivity of the mixed gas cooled to a predetermined temperature with oxygen and hydrogen. A burner introduced together with gas, and a seed rod for depositing glass fine particles synthesized by the oxyhydrogen reaction in the burner are attached, and the seed rod has a seed rod attachment means capable of moving up and down. A glass base material manufacturing apparatus adapted to manufacture a glass base material by pulling up the seed rod while depositing glass fine particles, wherein the liquid raw material vaporization apparatus vaporizes at least a liquid raw material for a dopant.
An apparatus for producing a glass base material, wherein the liquid raw material vaporizer according to any one of 3) is used.